Beyond Linux® From Scratch (System V Edition)

Version r11.0-1090

The BLFS Development Team

Copyright © 1999-2022, The BLFS Development Team

All rights reserved.

This book is licensed under a Creative Commons License.

Computer instructions may be extracted from the book under the MIT License.

Linux® is a registered trademark of Linus Torvalds.

Published 2022-05-06

Revision History
Revision r11.0-1090 2022-05-06 Ongoing Release
Revision 11.0 2021-09-01 Twenty-fourth Release
Revision 10.1 2021-03-01 Twenty-third Release
Revision 10.0 2020-09-01 Twenty-second Release
Revision 9.1 2020-03-01 Twenty-first Release
Revision 9.0 2019-09-01 Twentieth release
Revision 8.4 2019-03-01 Nineteenth release
Revision 8.3 2018-09-01 Eighteenth release
Revision 8.2 2018-03-02 Seventeenth release
Revision 8.1 2017-09-01 Sixteenth release
Revision 8.0 2017-02-25 Fifteenth release
Revision 7.10 2016-09-07 Fourteenth release
Revision 7.9 2016-03-08 Thirteenth release
Revision 7.8 2015-10-01 Twelfth release
Revision 7.7 2015-03-06 Eleventh release
Revision 7.6 2014-09-23 Tenth release
Revision 7.5 2014-03-05 Ninth release
Revision 7.4 2013-09-14 Eighth release
Revision 6.3 2008-08-24 Seventh release
Revision 6.2 2007-02-14 Sixth release
Revision 6.1 2005-08-14 Fifth release
Revision 6.0 2005-04-02 Fourth release
Revision 5.1 2004-06-05 Third release
Revision 5.0 2003-11-06 Second release
Revision 1.0 2003-04-25 First release

Abstract

This book follows on from the Linux From Scratch book. It introduces and guides the reader through additions to the system including networking, graphical interfaces, sound support, and printer and scanner support.


Dedication

This book is dedicated to the LFS community

Table of Contents

Preface

Having helped out with Linux From Scratch for a short time, I noticed that we were getting many queries as to how to do things beyond the base LFS system. At the time, the only assistance specifically offered relating to LFS were the LFS hints (https://www.linuxfromscratch.org/hints). Most of the LFS hints are extremely good and well written but I (and others) could still see a need for more comprehensive help to go Beyond LFS — hence BLFS.

BLFS aims to be more than the LFS-hints converted to XML although much of our work is based around the hints and indeed some authors write both hints and the relevant BLFS sections. We hope that we can provide you with enough information to not only manage to build your system up to what you want, whether it be a web server or a multimedia desktop system, but also that you will learn a lot about system configuration as you go.

Thanks as ever go to everyone in the LFS/BLFS community; especially those who have contributed instructions, written text, answered questions and generally shouted when things were wrong!

Finally, we encourage you to become involved in the community; ask questions on the mailing list or news gateway and join in the fun on #lfs and #lfs-support at Libera. You can find more details about all of these in the Introduction section of the book.

Enjoy using BLFS.

Mark Hymers
markh <at> linuxfromscratch.org
BLFS Editor (July 2001–March 2003)

I still remember how I found the BLFS project and started using the instructions that were completed at the time. I could not believe how wonderful it was to get an application up and running very quickly, with explanations as to why things were done a certain way. Unfortunately, for me, it wasn't long before I was opening applications that had nothing more than "To be done" on the page. I did what most would do, I waited for someone else to do it. It wasn't too long before I am looking through Bugzilla for something easy to do. As with any learning experience, the definition of what was easy kept changing.

We still encourage you to become involved as BLFS is never really finished. Contributing or just using, we hope you enjoy your BLFS experience.

Larry Lawrence
larry <at> linuxfromscratch.org
BLFS Editor (March 2003–June 2004)

The BLFS project is a natural progression of LFS. Together, these projects provide a unique resource for the Open Source Community. They take the mystery out of the process of building a complete, functional software system from the source code contributed by many talented individuals throughout the world. They truly allow users to implement the slogan Your distro, your rules.

Our goal is to continue to provide the best resource available that shows you how to integrate many significant Open Source applications. Since these applications are constantly updated and new applications are developed, this book will never be complete. Additionally, there is always room for improvement in explaining the nuances of how to install the different packages. To make these improvements, we need your feedback. I encourage you to participate on the different mailing lists, news groups, and IRC channels to help meet these goals.

Bruce Dubbs
bdubbs <at> linuxfromscratch.org
BLFS Editor (June 2004–December 2006 and February 2011–now)

My introduction to the [B]LFS project was actually by accident. I was trying to build a GNOME environment using some how-tos and other information I found on the web. A couple of times I ran into some build issues and Googling pulled up some old BLFS mailing list messages. Out for curiosity, I visited the Linux From Scratch web site and shortly thereafter was hooked. I've not used any other Linux distribution for personal use since.

I can't promise anyone will feel the sense of satisfaction I felt after building my first few systems using [B]LFS instructions, but I sincerely hope that your BLFS experience is as rewarding for you as it has been for me.

The BLFS project has grown significantly the last couple of years. There are more package instructions and related dependencies than ever before. The project requires your input for continued success. If you discover that you enjoy building BLFS, please consider helping out in any way you can. BLFS requires hundreds of hours of maintenance to keep it even semi-current. If you feel confident enough in your editing skills, please consider joining the BLFS team. Simply contributing to the mailing list discussions with sound advice and/or providing patches to the book's XML will probably result in you receiving an invitation to join the team.

Randy McMurchy
randy <at> linuxfromscratch.org
BLFS Editor (December 2006–January 2011)

Foreword

This version of the book is intended to be used when building on top of a system built using the LFS book. Every effort has been made to ensure accuracy and reliability of the instructions. Many people find that using the instructions in this book after building the current stable or development version of LFS provides a stable and very modern Linux system.

Enjoy!

Randy McMurchy
August 24th, 2008

Who Would Want to Read this Book

This book is mainly aimed at those who have built a system based on the LFS book. It will also be useful for those who are using other distributions, but for one reason or another want to manually build software and are in need of some assistance. Note that the material contained in this book, in particular the dependency listings, is based upon the assumption that you are using a base LFS system with every package listed in the LFS book already installed and configured. BLFS can be used to create a range of diverse systems and so the target audience is probably nearly as wide as that of the LFS book. If you found LFS useful, you should also like this!

Since Release 7.4, the BLFS book version matches the LFS book version. This book may be incompatible with a previous or later release of the LFS book.

Organization

This book is divided into the following parts.

Part I - Introduction

This part contains information which is essential to the rest of the book.

Part II - Post LFS Configuration and Extra Software

Here we introduce basic configuration and security issues. We also discuss a range of editors, file systems, and shells which aren't covered in the main LFS book.

Part III - General Libraries and Utilities

In this section we cover libraries which are often needed by the rest of the book as well as system utilities. Information on Programming (including recompiling GCC to support its full range of languages) concludes this part.

Part IV - Basic Networking

Here we cover how to connect to a network when you aren't using the simple static IP setup given in the main LFS book. Networking libraries and command-line networking tools are also covered here.

Part V - Servers

Here we deal with setting up mail and other servers (such as FTP, Apache, etc.).

Part VI - X + Window Managers

This part explains how to set up a basic X Window System installation along with some generic X libraries and Window managers.

Part VII - KDE

For those who want to use the K Desktop Environment or some parts of it, this part covers it.

Part VIII - GNOME

GNOME is the main alternative to KDE in the Desktop Environment arena.

Part IX - Xfce

Xfce is a lightweight alternative to GNOME and KDE.

Part X - LXDE

LXDE is another lightweight alternative to GNOME and KDE.

Part XI - X Software

Office programs and graphical web browsers are important to most people. They, along with some generic X software can be found in this part of the book.

Part XII - Multimedia

Here we cover setting multimedia libraries and drivers along with some audio, video and CD-writing programs.

Part XIII - Printing, Scanning and Typesetting (PST)

The PST part of the book covers document handling with applications like Ghostscript, CUPS and DocBook to installing texlive.

Appendices

The Appendices cover information which doesn't belong in the main book; they are mainly there as a reference.

Part I. Introduction

Chapter 1. Welcome to BLFS

The Beyond Linux From Scratch book is designed to carry on from where the LFS book leaves off. But unlike the LFS book, it isn't designed to be followed straight through. Reading the Which sections of the book? part of this chapter should help guide you through the book.

Please read most of this part of the book carefully as it explains quite a few of the conventions used throughout the book.

Which Sections of the Book Do I Want?

Unlike the Linux From Scratch book, BLFS isn't designed to be followed in a linear manner. This is because LFS provides instructions on how to create a base system which is capable of turning into anything from a web server to a multimedia desktop system. BLFS attempts to guide you in the process of going from the base system to your intended destination. Choice is very much involved.

Everyone who reads the book will want to read certain sections. The Introduction part, which you are currently reading, contains generic information. Especially take note of the information in Chapter 2, Important Information, as this contains comments about how to unpack software, issues related to using different locales and various other aspects which apply throughout the book.

The part on Post LFS Configuration and Extra Software is where most people will want to turn next. This deals with not just configuration but also Security (Chapter 4, Security), File Systems (Chapter 5, File Systems and Disk Management), Editors (Chapter 6, Editors) and Shells (Chapter 7, Shells). Indeed, you may wish to reference certain parts of this chapter (especially the sections on Editors and File Systems) while building your LFS system.

Following these basic items, most people will want to at least browse through the General Libraries and Utilities part of the book. This part contains information on many items which are prerequisites for other sections of the book as well as some items (such as Chapter 13, Programming) which are useful in their own right. Note that you don't have to install all of these libraries and packages found in this part to start with as each BLFS installation procedure tells you which packages it depends upon so you can choose the program you want to install and see what it needs.

Likewise, most people will probably want to look at the Networking part. It deals with connecting to the Internet or your LAN (Chapter 14, Connecting to a Network) using a variety of methods such as DHCP and PPP, and with items such as Networking Libraries (Chapter 17, Networking Libraries) and various basic networking programs and utilities.

Once you have dealt with these basics, you may wish to configure more advanced network services. These are dealt with in the Servers part of the book. Those wanting to build servers should find a good starting point there. Note that this section also contains information on various database packages.

The next parts of the book principally deal with desktop systems. This portion of the book starts with a part talking about Graphical Components. This part also deals with some generic X-based libraries (Chapter 25, Graphical Environment Libraries). After this, KDE and GNOME are given their own parts which are followed by one on X Software.

The book then moves on to deal with Multimedia packages. Note that many people may want to use the ALSA-1.2.6 instructions from this chapter quite near the start of their BLFS journey; they are placed here simply because it is the most logical place for them.

The final part of the main BLFS book deals with Printing, Scanning and Typesetting. This is useful for most people with desktop systems and even those who are creating mainly server systems will find it useful.

We hope you enjoy using BLFS and find it useful.

Conventions Used in this Book

Typographical Conventions

To make things easy to follow, there are a number of conventions used throughout the book. Following are some examples:

./configure --prefix=/usr

This form of text is designed to be typed exactly as seen unless otherwise noted in the surrounding text. It is also used to identify references to specific commands.

install-info: unknown option
`--dir-file=/mnt/lfs/usr/info/dir'

This form of text (fixed width text) is showing screen output, probably a result from issuing a command. It is also used to show filenames such as /boot/grub/grub.conf

Emphasis

This form of text is used for several purposes in the book but mainly to emphasize important points or to give examples as to what to type.

https://www.linuxfromscratch.org/

This form of text is used for hypertext links external to the book such as HowTos, download locations, websites, etc.

SeaMonkey-2.53.11.1

This form of text is used for links internal to the book such as another section describing a different package.

cat > $LFS/etc/group << "EOF"
root:x:0:
bin:x:1:
......
EOF

This type of section is used mainly when creating configuration files. The first command (in bold) tells the system to create the file $LFS/etc/group from whatever is typed on the following lines until the sequence EOF is encountered. Therefore, this whole section is generally typed as seen.

<REPLACED TEXT>

This form of text is used to encapsulate text that should be modified and is not to be typed as seen, or copy and pasted. Note that the square brackets are not part of the text, but should be substituted for as well.

root

This form of text is used to show a specific system user or group reference in the instructions.

Conventions Used for Package Dependencies

When packages are created, the authors depend on prior work. In order to build a package in BLFS, these dependencies must be built prior to the desired package. For each package, any prerequisite packages are listed in one or more separate sections: Required, Recommended, and Optional.

Required Dependencies

These dependencies are the minimum prerequisite packages required to build the package. Omitted from the list are packages in LFS and required dependencies of other required packages.

Recommended Dependencies

These dependencies are those that the BLFS editors have determined are important to give the package reasonable capabilities. Package installation instructions assume they are installed. If a recommended package is not desired, the instructions may need to be modified to accommodate the missing package.

Optional Dependencies

These dependencies are those that the package may use. Integration of optional dependencies may be automatic by the package or may need additional instructions not presented by BLFS. Optional packages may be listed without corresponding BLFS instructions. In this case it is up to the user to determine appropriate installation instructions.

Conventions Used for Kernel Configuration Options

Some packages have specific needs regarding the kernel configuration. The general layout is the following:

Master section --->
  Subsection --->
    [*]     Required parameter                     [CONFIG_REQU_PAR]
    <*>     Required parameter (not as module)     [CONFIG_REQU_PAR_NMOD]
    <*/M>   Required parameter (could be a module) [CONFIG_REQU_PAR_MOD]
    <*/M/ > Optional parameter                     [CONFIG_OPT_PAR]
    [ ] Incompatible parameter                     [CONFIG_INCOMP_PAR]
    < > Incompatible parameter (even as module)    [CONFIG_INCOMP_PAR_MOD]

[CONFIG_...] on the right gives the name of the option, so you can easily check whether it is set in your config file. The meaning of the various entries is:

Master section top level menu item
Subsection submenu item
Required parameter the option could be either built-in or not selected: it must be selected
Required parameter (not as module) the option could be either built-in, module, or not selected: it must be selected as built-in
Required parameter (could be a module) the option could be either built-in, module, or not selected: it must be selected, either as built-in or module
Optional parameter rarely used: the option could be either built-in, module, or not selected: it may be selected at will
Incompatible parameter the option could be either built-in or not selected: it must not be selected
Incompatible parameter (even as module) the option could be either built-in, module, or not selected: it must not be selected

Note that, depending on other selections, the angle brackets (<>) may appear as braces ({}), if the option cannot be unselected, or even dashes (-*- or -M-), when the choice is imposed. The help text about the option specifies the other selections on which this option relies, and how those other selections are set.

SBU values in BLFS

As in LFS, each package in BLFS has a build time listed in Standard Build Units (SBUs). These times are relative to the time it took to build binutils in LFS and are intended to provide some insight into how long it will take to build a package. Most times listed are for a single processor or core to build the package. In some cases, large, long running builds tested on multi-core systems have SBU times listed with comments such as '(parallelism=4)'. These values indicate testing was done using multiple cores. Note that while this speeds up the build on systems with the appropriate hardware, the speedup is not linear and to some extent depends on the individual package and specific hardware used.

For packages which use ninja (e.g. anything using meson) or rust, by default all cores are used so similar comments will be seen on such packages even when the build time is minimal.

Where even a parallel build takes more than 15 SBU, on certain machines the time may be considerably greater even when the build does not use swap. In particular, different micro-architectures will build some files at different relative speeds and this can introduce delays when certain make targets wait for another file to be created. Where a large build uses a lot of C++ files, processors with Simultaneous Multi Threading will share the Floating Point Unit and can take 45% longer than when using four 'prime' cores (measured on an intel i7 using taskset and keeping the other cores idle).

Some packages do not support parallel builds and using -j1 for the make command is required. Packages that are known to have such limits are marked as such in the text.

Book Version

This is BLFS-BOOK version r11.0-1090 dated May 6th, 2022. This is the svn branch of the BLFS book, currently targeting the LFS development book. For development versions, if this version is older than a month, it's likely that your mirror hasn't been synchronized recently and a newer version is probably available for download or viewing. Check one of the mirror sites at https://www.linuxfromscratch.org/mirrors.html for an updated version.

Mirror Sites

The BLFS project has a number of mirrors set up world-wide to make it easier and more convenient for you to access the website. Please visit the https://www.linuxfromscratch.org/mirrors.html website for the list of current mirrors.

Getting the Source Packages

Within the BLFS instructions, each package has two references for finding the source files for the package—an HTTP link and an FTP link (some packages may only list one of these links). Every effort has been made to ensure that these links are accurate. However, the World Wide Web is in continuous flux. Packages are sometimes moved or updated and the exact URL specified is not always available.

To overcome this problem, the BLFS Team, with the assistance of Oregon State University Open Source Lab, has made an HTTP/FTP site available through world wide mirrors. See https://www.linuxfromscratch.org/blfs/download.html#sources for a list. These sites have all the sources of the exact versions of the packages used in BLFS. If you can't find the BLFS package you need at the listed addresses, get it from these sites.

We would like to ask a favor, however. Although this is a public resource for you to use, please do not abuse it. We have already had one unthinking individual download over 3 GB of data, including multiple copies of the same files that are placed at different locations (via symlinks) to make finding the right package easier. This person clearly did not know what files he needed and downloaded everything. The best place to download files is the site or sites set up by the source code developer. Please try there first.

Change Log

Current release: r11.0-1090 – May 6th, 2022

Changelog Entries:

  • May 6th, 2022

    • [xry111] - Update to vim-8.2.4814 (security fix). Sync with LFS.

    • [pierre] - Update to libreoffice-7.3.3. Fixes #16515.

  • May 5th, 2022

    • [pierre] - Update to poppler-22.05.0. Fixes #16516.

    • [bdubbs] - Update to libnotify-0.7.12. Fixes #16517.

    • [bdubbs] - Update to wireshark-3.6.5. Fixes #16512.

    • [bdubbs] - Update to xfsprogs-5.16.0. Fixes #16509.

    • [xry111] - Update to sqlite-autoconf-3380400 (3.38.4). Fixes #16514.

    • [timtas] - Update to openldap-2.6.2. Fixes #16513.

  • May 3rd, 2022

    • [bdubbs] - Update to libxcb-1.15. Fixes #16505.

    • [bdubbs] - Update to xcb-proto-1.15. Fixes #16506.

  • May 3rd, 2022

    • [bdubbs] - Update to libxml2-2.9.14. Fixes #16500.

    • [bdubbs] - Update to gstreamer-1.20.2 gst-plugins-base gst-plugins-good gst-plugins-bad gst-plugins-ugly gst-libav gstreamer-vaapi. Fixes #16504.

    • [ken] - Update to firefox-91.9.0 (security fix) and js-91.9.0. Fixes #16498.

    • [timtas] - Update to unixODBC-2.3.10. Fixes #16501.

  • May 2, 2022

    • [bdubbs] - Update to gdb-12.1. Fixes #16496.

    • [bdubbs] - Update to icewm-2.9.7. Fixes #16497.

    • [bdubbs] - Update to freetype-2.12.1. Fixes #16495.

  • May 1, 2022

    • [bdubbs] - Update to LWP (Perl module libwww-perl-6.64). Fixes #16492.

    • [ken] - Update to asymptote-2.79. Addresses #16207.

    • [ken] - Update to dvisvgm-2.13.3. Fixes #16167.

    • [ken] - Update to texlive-2022. Fixes #16240.

  • April 30, 2022

    • [bdubbs] - Update to libX11-1.8. Fixes #16490.

    • [bdubbs] - Update to gcc-11.3.0. Fixes #16445.

    • [bdubbs] - Update to Jinja2-3.1.2. Fixes #16487.

    • [pierre] - Update to pipewire-0.3.51. Fixes #16489.

    • [pierre] - Update to nss-3.78. Fixes #16483.

    • [pierre] - Update to ModemManager-1.18.8. Fixes #16486.

    • [pierre] - Update to libqmi-1.30.6. Fixes #16485.

    • [pierre] - Update to libmbim-1.26.4. Fixes #16484.

    • [pierre] - Update to pidgin-2.4.19 (security fix). Fixes #16488.

  • April 28th, 2022

    • [bdubbs] - Update to nano-6.3. Fixes #16481.

    • [bdubbs] - Update to gnome-desktop-42.1. Fixes #16480.

    • [bdubbs] - Update to libnotify-0.7.11. Fixes #16479.

    • [bdubbs] - Update to gtk-4.6.3. Fixes #16482.

    • [bdubbs] - Update to sqlite-autoconf-3380300 (3.38.3). Fixes #16478.

    • [bdubbs] - Update to postfix-3.7.2. Fixes #16477.

    • [bdubbs] - Update to curl-7.83.0. Fixes #16476.

    • [bdubbs] - Update to lsof_4.95.0. Fixes #16475.

  • April 27th, 2022

    • [bdubbs] - Update to zenity-3.42.1. Fixes #16473.

    • [bdubbs] - Update to fetchmail-6.4.30. Fixes #16472.

    • [bdubbs] - Update to node-16.15.0. Fixes #16471.

    • [bdubbs] - Update to btrfs-progs-v5.17. Fixes #16470.

  • April 26th, 2022

    • [bdubbs] - Update to gnome-control-center-42.1. Fixes #16469.

    • [bdubbs] - Update to SDL2-2.0.22. Fixes #16468.

    • [bdubbs] - Update to gnupg-2.3.6. Fixes #16467.

    • [pierre] - Update to java-18.0.1 binary. Fixes #16453.

    • [pierre] - Update to OpenJDK-18.0.1. Part of #16453.

  • April 25th, 2022

    • [pierre] - JS-91 needs the same fix as firefox for 32 bit machines.

    • [bdubbs] - Update to harfbuzz-4.2.1. Fixes #16465.

    • [bdubbs] - Update to Pygments-2.12.0. Fixes #16466.

  • April 24th, 2022

    • [bdubbs] - Update to imlib2-1.9.0. Fixes #16464.

    • [bdubbs] - Update to eog-42.1. Fixes #16463.

    • [bdubbs] - Update to proftpd-1.3.7d. Fixes #16462.

  • April 23rd, 2022

    • [bdubbs] - Update to libhandy-1.6.2. Fixes #16461.

    • [bdubbs] - Update to gnome-maps-42.1. Fixes #16460.

    • [bdubbs] - Update to nautilus-42.1.1. Fixes #16459.

    • [bdubbs] - Update to libadwaita-1.1.1. Fixes #16458.

    • [bdubbs] - Update to vala-0.56.1. Fixes #16457.

    • [bdubbs] - Update to evolution iand evolution-data-server 3.44.1. Fixes #16454.

  • April 22nd, 2022

    • [xry111] - Update to librsvg-2.54.1. Fixes #16456.

    • [bdubbs] - Update to thunderbird-91.8.1. Fixes #16438.

    • [bdubbs] - Update to gvfs-1.50.1. Fixes #16455.

    • [bdubbs] - Update to gnumeric-1.12.52. Fixes #16430.

    • [bdubbs] - Update to goffice-0.10.52. Fixes #16429.

    • [bdubbs] - Update to gspell-1.10.0. Fixes #16431.

    • [bdubbs] - Update to libseccomp-2.5.4. Fixes #16451.

    • [bdubbs] - Update to at-spi2-core-2.44.1. Fixes #16450.

    • [bdubbs] - Update to epiphany-42.2. Fixes #16449.

    • [bdubbs] - Update to gtksourceview-5.4.1. Fixes #16448.

    • [bdubbs] - Update to gnupg-2.3.5. Fixes #16447.

  • April 21st, 2022

    • [bdubbs] - Update to vlc-3.0.17.4. Fixes #16444.

    • [bdubbs] - Update to bind and bind-utilities-9.18.2. Fixes #16442.

    • [bdubbs] - Update to webkitgtk-2.36.1. Fixes #16446.

    • [bdubbs] - Update to jasper-3.0.3. Fixes #16435.

    • [timtas] - Update to qemu-7.0.0. Fixes #16434.

    • [bdubbs] - Update to xorgproto-2022.1. Fixes #16443.

    • [bdubbs] - Update to libinput-1.20.1 (Xorg driver). Fixes #16440.

    • [bdubbs] - Update to libaio-0.3.113. Fixes #16439.

    • [bdubbs] - Update to xauth-1.1.2 (Xorg app). Fixes #16437.

    • [bdubbs] - Update to cbindgen-0.23.0. Fixes #16436.

    • [bdubbs] - Update to postfix-3.7.1. Fixes #16428.

  • April 20th, 2022

    • [timtas] - Update to xfce4-terminal-1.0.2. Fixes #16441.

  • April 19th, 2022

    • [pierre] - Update to git-2.36.0. Fixes #16427.

    • [pierre] - Update to pciutils-3.8.0. Fixes #16426.

    • [pierre] - Update to parted-3.5. Fixes #16425.

    • [renodr] - Archive Amtk.

    • [renodr] - Archive Tepl.

    • [renodr] - Fix building Inkscape with poppler-22.04.0. Fixes #16433.

  • April 18th, 2022

    • [bdubbs] - Update to pygobject-3.42.1 (Python module). Fixes #16424.

  • April 16th, 2022

    • [bdubbs] - Update to evince-42.2. Fixes #16422.

    • [bdubbs] - Update to enchant-2.3.3. Fixes #16420.

    • [bdubbs] - Update to epiphany-42.1. Fixes #16403.

    • [bdubbs] - Update to gcr-3.41.0. Fixes #16421.

    • [bdubbs] - Update to xfce4-panel-4.16.4. Fixes #16423.

    • [bdubbs] - Update to rsync-3.2.4. Fixes #16418.

    • [bdubbs] - Update to pcre2-10.40. Fixes #16417.

    • [bdubbs] - Update to libnl-3.6.0. Fixes #16419.

  • April 15th, 2022

    • [ken] - Update to mutt-2.2.3 (Security Update). Fixes #16406.

    • [renodr] - Update to ruby-3.1.2 (Security Update). Fixes #16405.

    • [renodr] - Update to git-2.35.3 (Security Update). Fixes #16402.

  • April 14th, 2022

    • [bdubbs] - Update to gptfdisk-1.0.9. Fixes #16415.

    • [bdubbs] - Update to pango-1.50.7. Fixes #16414.

    • [bdubbs] - Update to php-8.1.5. Fixes #16413.

    • [bdubbs] - Update to glib-2.72.1. Fixes #16412.

    • [bdubbs] - Update to pipewire-0.3.50. Fixes #16411.

    • [bdubbs] - Update to json-c-0.16. Fixes #16410.

    • [bdubbs] - Update to boost_1_79_0. Fixes #16409.

    • [bdubbs] - Update to llvm-14.0.1. Fixes #16408.

    • [bdubbs] - Update to cmake-3.23.1. Fixes #16404.

    • [bdubbs] - Update to libcap-2.64. Fixes #16397.

    • [timtas] - Update to xfce4-terminal-1.0.1. Fixes #16407.

  • April 12th, 2022

    • [bdubbs] - Update to valgrind-3.19.0. Fixes #16401.

    • [bdubbs] - Update to links-2.26. Fixes #16399.

    • [bdubbs] - Update to libnma-1.8.38. Fixes #16392.

    • [bdubbs] - Update to icu4c-71_1-src. Fixes #16389.

    • [bdubbs] - Update to openssh-9.0p1. Includes ssh-askpass. Fixes #16387.

    • [bdubbs] - Update to mercurial-6.1.1. Fixes #16378.

  • April 12th, 2022

    • [bdubbs] - Update to umockdev-0.17.9. Fixes #16396.

    • [bdubbs] - Update to libusb-1.0.26. Fixes #16395.

    • [bdubbs] - Update to XML-LibXSLT-2.000000 (Perl module). Fixes #16394.

    • [bdubbs] - Update to libarchive-3.6.1. Fixes #16393.

    • [bdubbs] - Update to xclock-1.1.1. Fixes #16391.

    • [bdubbs] - Update to python-dbusmock-0.27.5 (Python module). Fixes #16390.

    • [bdubbs] - Update to libgpg-error-1.45. Fixes #16388.

    • [bdubbs] - Update to xdpyinfo-1.3.3 (Xorg App). Fixes #16386.

    • [bdubbs] - Update to xfsprogs-5.15.0. Fixes #16384.

    • [bdubbs] - Update to cups-filters-1.28.15. Fixes #16376.

    • [bdubbs] - Update to mupdf-1.19.1. Fixes #16383.

    • [bdubbs] - Update to ghostscript-9.56.1. Fixes #16375.

    • [timtas] - Update to subversion-1.14.2. Fixes #16398.

    • [renodr] - Fix a typo in babl's meson.build file that causes it to not build. Reported by John Burrell.

  • April 11th, 2022

    • [pierre] - Update to rust-1.60.0. Fixes #16400.

    • [pierre] - Add a note about the extracted directories in LLVM. Fixes #16385.

  • April 10th, 2022

    • [ken] - Update to qtwebengine-5.15.9 (Security fix). Fixes #16277.

    • [pierre] - Update to epiphany-42.0. Fixes #16249.

    • [pierre] - Update to gucharmap-14.0.3. Fixes #16335.

    • [pierre] - Update to gnome-weather-42.0. Fixes #16295.

    • [pierre] - Update to gnome-terminal-3.44.0. Fixes #16334.

    • [pierre] - Update to gnome-system-monitor-42.0. Fixes #16287.

    • [pierre] - Update to gnome-nettool-42.0. Fixes #16380.

    • [pierre] - Update to gnome-maps-42.0. Fixes #16286.

    • [pierre] - Update to gnome-disk-utility-42.0. Fixes #16264.

    • [pierre] - Update to gnome-calculator-42.0. Fixes #16285.

    • [pierre] - Update to file-roller-3.42.0. Fixes #16294.

    • [pierre] - Update to evolution-3.44.0. Fixes #16263.

    • [pierre] - Update to evince-42.1. Fixes #16262.

    • [pierre] - Update to eog-42.0. Fixes #16278.

    • [pierre] - Update to baobab-42.0. Fixes #16293.

    • [pierre] - Update to yelp-42.1. Fixes second part of #16289.

    • [pierre] - Update to yelp-xsl-42.0. Fixes first part of #16289.

    • [pierre] - Update to vte-0.68.0. Fixes #16333.

    • [pierre] - Update to nautilus-42.0. Fixes #16282.

    • [pierre] - Update to trackers-miner-3.3.0. Fixes second part of #16283.

    • [pierre] - Update to libpeas-1.32.0. Fixes #16261.

    • [pierre] - Update to gnome-user-doc-42.0. Fixes #16290.

    • [pierre] - Update to gnome-shell-extensions-42.0. Fixes second part of #16269.

    • [pierre] - Update to gnome-backgrouns-42.0. Fixes #16303.

    • [pierre] - Update to gnome-shell-42.0. Fixes part of #16269.

    • [pierre] - Update to gnome-control-center-42.0. Fixes #16275.

    • [pierre] - Update to mutter-42.0. Fixes #16270.

    • [pierre] - Update to zenity-3.42.0. Fixes #16358.

  • April 9th, 2022

    • [pierre] - Update to gnome-bluetooth-42.0. Fixes #16259.

    • [pierre] - Update to gvfs-1.50.0. Fixes #16260.

    • [pierre] - Update to gnome-settings-daemon-42.1. Fixes #16301.

    • [pierre] - Update to gnome-session-42.0. Fixes #16306.

    • [pierre] - Update to gdm-42.0. Fixes #16305.

    • [pierre] - Update to folks-0.15.5. Fixes #16314.

    • [pierre] - Update to evolution-data-server-3.44.0. Fixes #16258.

    • [pierre] - Update to libgweather-4.0.0. Fixes #16268.

  • April 8th, 2022

    • [pierre] - Update to gnome-online-accounts-3.44.0. Fixes #16349.

    • [pierre] - Update to tracker-3.3.0. Partially fixes #16283.

    • [pierre] - Update to gnome-desktop-42.0. Fixes #16274.

    • [pierre] - Update to gjs-1.72.0. Fixes #16288.

    • [pierre] - Update to gsettings-desktop-schemas-42.0. Fixes #16272.

  • April 7th, 2022

    • [bdubbs] - Update to libmnl-1.0.5. Fixes #16379.

    • [bdubbs] - Update to python-dbusmock-0.27.4 (Python module). Fixes #16373.

    • [bdubbs] - Update to libqalculate-4.1.1. Fixes #16372.

    • [timtas] - Update to thunderbird-91.8.0. Fixes #16381.

  • April 5th, 2022

    • [ken] - Update to firefox-91.8.0 (security update) and JS-91.8.0. Fixes #16374.

    • [timtas] - Update to emacs-28.1. Fixes #16371.

  • April 3rd, 2022

    • [bdubbs] - Update to xclock-1.1.0. Fixes #16370.

    • [bdubbs] - Update to setxkbmap-1.3.3 (Xorg app). Fixes #16369.

    • [bdubbs] - Update to mkfontscale-1.2.2 (xorg app). Fixes #16368.

    • [bdubbs] - Update to mutt-2.2.2. Fixes #16344.

    • [bdubbs] - Update to fetchmail-6.4.29. Fixes #16292.

  • April 3rd, 2022

    • [bdubbs] - Update to gnupg-2.3.4. Fixes #14876.

    • [bdubbs] - Add -Dgpl=enabled to gst-plugins-{bad,ugly}. Fixes #16322.

    • [bdubbs] - Update to gstreamer-1.20.1. Includes gst-plugins-{base,good,bad,ugly}, gstlibav, and gstreamer-vaapi. Fixes #16233.

    • [bdubbs] - Update to thunar-4.16.11. Fixes #16365.

    • [bdubbs] - Update to iceauth-1.0.9 (Xorg App). Fixes #16367.

    • [bdubbs] - Update to libXcursor-1.2.1 (Xorg Library). Fixes #16364.

    • [bdubbs] - Update to libX11-1.7.5 (Xorg Library). Fixes #1636.

    • [bdubbs] - Update to poppler-22.04.0. Fixes #16361.

    • [bdubbs] - Update to mousepad-9.5.9. Fixes #16362.

    • [bdubbs] - Update to twm-1.0.12. Fixes #16363.

  • April 2nd, 2022

    • [bdubbs] - Update to gedit-42.0. Fixes #16360.

    • [bdubbs] - Update to xfce4-terminal-1.0.0. Fixes #16359.

  • April 1st, 2022

    • [bdubbs] - Update to freetype-2.12.0. Fixes #16356.

    • [bdubbs] - Update to fontconfig-2.14.0. Fixes #16355.

    • [bdubbs] - Update to xwayland-22.1.1. Fixes #16357.

    • [bdubbs] - Update to libreoffice-7.3.2.2. Fixes #16353.

    • [bdubbs] - Update to nss-3.77. Fixes #16354.

  • March 31st, 2022

    • [bdubbs] - Update to ghostscript-9.56.0. Fixes #16352.

    • [bdubbs] - Update to libX11-1.7.4 (Xorg library). Fixes #16351.

    • [bdubbs] - Update to harfbuzz-4.2.0. Fixes #16350.

    • [bdubbs] - Update to atk-2.38.0. Fixes #16348.

    • [bdubbs] - Update to pipewire-0.3.49. Fixes #16347.

    • [bdubbs] - Update to mlt-7.6.0. Fixes #16346.

    • [bdubbs] - Update to cmake-3.23.0. Fixes #16345.

  • March 30th, 2022

    • [bdubbs] - Update to Python-3.10.4. Fixes #16321.

    • [bdubbs] - Update to Jinja2-3.1.1 (Python module). Fixes #16320.

  • March 29th, 2022

    • [bdubbs] - Update to HTML-Parser-3.78 (Perl module). Fixes #16343.

    • [bdubbs] - Update to libgcrypt-1.10.1. Fixes #16342.

    • [bdubbs] - Update to nss-3.76.1. Fixes #16341.

    • [bdubbs] - Update to gparted-1.4.0. Fixes #16340.

  • March 28th, 2022

    • [bdubbs] - Update to cups-filters-1.28.13. Fixes #16338.

    • [bdubbs] - Update to libsndfile-1.1.0. Fixes #16337.

    • [bdubbs] - Update to frei0r-plugins-1.8.0. Fixes #16336.

    • [bdubbs] - Update to mc-4.8.28. Fixes #16331.

    • [bdubbs] - Update to shared-mime-info-2.2. Fixes #16330.

    • [timtas] - Update to at-3.2.5. Fixes #16332.

  • March 27th, 2022

    • [bdubbs] - Update to libXvMC-1.0.13 (Xorg library). Fixes #16329.

    • [bdubbs] - Update to sqlite-autoconf-3380200 (3.38.2). Fixes #16328.

  • March 26th, 2022

    • [bdubbs] - Update to libnma-1.8.36. Fixes #16327.

    • [bdubbs] - Update to cbindgen-0.21.0. Fixes #16326.

    • [bdubbs] - Update to libwacom-2.2.0. Fixes #16325.

    • [bdubbs] - Update to libevdev-1.12.1 (Xorg driver). Fixes #16324.

    • [bdubbs] - Update to seamonkey-2.53.11.1. Fixes #16323.

    • [bdubbs] - Update to llvm-14.0.0. Fixes #16315.

  • March 25th, 2022

    • [bdubbs] - Update to wireshark-3.6.3. Fixes #16319.

    • [bdubbs] - Update to harfbuzz-4.1.0. Fixes #16318.

    • [bdubbs] - Update to umockdev-0.17.8. Fixes #16317.

    • [bdubbs] - Update to inih-r55. Fixes #16316.

    • [bdubbs] - Update to glib-networking-2.72.0. Fixes #16313.

    • [bdubbs] - Update to python-dbusmock-0.27.3. Fixes #16311.

    • [bdubbs] - Update to highlight-4.2. Fixes #16310.

    • [bdubbs] - Update to babl-0.1.92. Fixes #16309.

    • [bdubbs] - Update to webkitgtk-2.36.0. Fixes #16304.

    • [ken] - Fix x265 when git has not been installed.

  • March 24th, 2022

    • [bdubbs] - Update to sysprof-3.44.0. Fixes #16299.

    • [bdubbs] - Add libunwind-1.6.2 in support of sysprof-3.44.0.

    • [bdubbs] - Add libadwaita-1.1.0 in support of GNOME-42. Fixes #16271.

    • [bdubbs] - Update to network-manager-applet-1.26.0. Fixes #16308.

    • [bdubbs] - Update to NetworkManager-1.36.4. Fixes #16312.

  • March 22nd, 2022

    • [bdubbs] - Update to libportal-0.6. Fixes #16307.

    • [bdubbs] - Update to pango-1.50.6. Fixes #16300.

    • [bdubbs] - Update to adwaita-icon-theme-42.0. Fixes #16302.

    • [bdubbs] - Update to cairo-1.17.6. Fixes #16298.

    • [bdubbs] - Update to libepoxy-1.5.10. Fixes #16297.

    • [bdubbs] - Update to graphene-1.10.8. Fixes #16296.

    • [bdubbs] - Update to libgsf-1.14.49. Fixes #16291.

    • [renodr] - Update to krb5-1.19.3. Fixes #16228.

    • [renodr] - Update to Samba-4.16.0. Fixes #16234.

    • [renodr] - Add the JSON perl module for Samba.

    • [bdubbs] - Enable gtk4 library for libnma. Fixes #16273.

    • [bdubbs] - Update to libhandy-1.6.1. Fixes #16266.

    • [bdubbs] - Update to libdazzle-3.44.0. Fixes #16257.

    • [renodr] - Update to Thunderbird-91.7.0 (Security Update). Fixes #16216.

  • March 21st, 2022

    • [bdubbs] - Update to gtksourceview-5.4.0. Fixes #16256.

    • [bdubbs] - Update to gtksourceview-4.8.3. Fixes #16255.

    • [bdubbs] - Update to gtk4-4.6.2. Fixes #16254.

    • [bdubbs] - Update to at-spi2-core-2.44.0. Fixes #16252.

  • March 20th, 2022

    • [bdubbs] - Update to vala-0.56.0. Fixes #16279.

    • [bdubbs] - Update to glib-2.72.0. Fixes #16267.

    • [bdubbs] - Update to gobject-introspection-1.72.0. Fixes #16251.

    • [bdubbs] - Update to php-8.1.4. Fixes #16248.

    • [bdubbs] - Update to liblinear-244. Fixes #16247.

    • [bdubbs] - Update to gnutls-3.7.4. Fixes #16246.

    • [bdubbs] - Update to bluez-5.64. Fixes #16242.

    • [xry111] - Update to Python-3.10.3. Fixes #16243.

  • March 19th, 2022

    • [timtas] - Update to gdk-pixbuf-2.42.8. Fixes #16253.

  • March 18th, 2022

    • [bdubbs] - Update to node-16.14.2. Fixes #16241.

    • [timtas] - Added optional x265 dependency for heif support in imlib2-1.8.1.

  • March 17th, 2022

    • [xry111] - Update to librsvg-2.54.0. Fixes #16244.

    • [bdubbs] - Update to bind-9.18.1. Fixes #16239.

    • [bdubbs] - Update to imlib2-1.8.1. Fixes #16238.

    • [bdubbs] - Update to stunnel-5.63. Fixes #16236.

    • [bdubbs] - Update to httpd-2.4.53 (security update). Fixes #16232.

    • [bdubbs] - Update to HTML-Parser-3.77 (Perl module). Fixes #16231.

    • [bdubbs] - Update to ibus-1.5.26. Fixes #16230.

    • [bdubbs] - Update to libqalculate-4.1.0. Fixes #16229.

  • March 16th, 2022

    • [renodr] - Update to fetchmail-6.4.28. Fixes #16200.

    • [renodr] - Update to NetworkManager-1.36.2. Fixes #16170.

    • [xry111] - Update to MarkupSafe-2.1.1 (Python module). Fixes #16237.

  • March 15th, 2022

    • [timtas] - Add transmission-3.00-pidfile_doc-1.patch.

    • [xry111] - Update to vim-8.2.4567 (security fix). Sync with LFS.

  • March 14th, 2022

    • [ken] - Update to firefox-91.7.1 (and js-91.7.1). Fixes #16225.

    • [bdubbs] - Update to evince-41.4. Fixes #16227.

  • March 13th, 2022

    • [bdubbs] - Update to sqlite-autoconf-3380100 (3.38.1). Fixes #16224.

    • [bdubbs] - Update to qpdf-10.6.3. Fixes #16223.

    • [pierre] - Update to tracker-miners-3.2.2. Fixes #16203.

  • March 12th, 2022

    • [bdubbs] - Update to vlc-3.0.17.3 Fixes #16222.

    • [bdubbs] - Update to librsvg-2.52.7. Fixes #16221.

    • [xry111] - Update to harfbuzz-4.0.1. Fixes #16220.

    • [pierre] - Allow elogind to exit when dbus is closed. Fixes #16177.

  • March 11th, 2022

    • [bdubbs] - Update to dhcp-4.4.3. Fixes #16213.

  • March 10th, 2022

    • [bdubbs] - Update to Mako-1.2.0 (Python module). Fixes #16219.

    • [bdubbs] - Update to harfbuzz-4.0.0. Fixes #16183.

    • [bdubbs] - Update to xine-lib-1.2.12. Fixes #16217.

    • [bdubbs] - Update to xterm-372. Fixes #16215.

    • [bdubbs] - Update to upower-v0.99.17. Fixes #16212.

    • [bdubbs] - Update to vlc-3.0.17. Fixes #16211.

    • [bdubbs] - Archive libuninameslist.

    • [bdubbs] - Update to fontforge-20220308. Fixes #16210.

    • [bdubbs] - Update to libvdpau-1.5 (Xorg driver). Fixes #16208.

    • [bdubbs] - Update to libuv-v1.44.1. Fixes #16205.

  • March 9th, 2022

    • [bdubbs] - Update to pycairo-1.21.0 (Python module). Fixes #16206.

    • [bdubbs] - Update to xscreensaver-6.03. Fixes #16180.

    • [bdubbs] - Update to sysstat-12.5.6. Fixes #16179.

    • [bdubbs] - Update to libreoffice-7.3.1.3. Fixes #16191.

  • March 8th, 2022

    • [renodr] - Fix CVE-2022-26485 in Seamonkey. Fixes #16202.

    • [renodr] - Fix building Inkscape with poppler-22.03.0. Fixes #16209.

    • [renodr] - Update to curl-7.82.0. Fixes #16198.

    • [renodr] - Update to thunderbird-91.6.2 (Security Update). Fixes #16201.

    • [bdubbs] - Update to gpgme-1.17.1. Fixes #16204.

    • [bdubbs] - Update to pango-1.50.5. Fixes #16199.

    • [bdubbs] - Update to cmake-3.22.3. Fixes #16196.

    • [ken] - Update to firefox-91.7.0 (security update). Fixes #16197.

    • [bdubbs] - Refine instructions for SCons-4.3.0. Fixes #16195.

    • [bdubbs] - Update to gtk+-3.24.33. Fixes #16194.

    • [bdubbs] - Update to pipewire-0.3.48. Fixes #16192.

    • [renodr] - Update to ruby-3.1.1. Fixes #16143.

    • [renodr] - Update to nss-3.76. Fixes #16193.

  • March 7th, 2022

    • [bdubbs] - Update to sudo-1.9.10. Fixes #16188.

    • [bdubbs] - Update to umockdev-0.17.7. Fixes #16186.

    • [bdubbs] - Update to poppler-22.03.0. Fixes #16184.

    • [bdubbs] - Update to HTTP-Daemon-6.14 (Perl Module). Fixes #16189.

    • [bdubbs] - Update to python-dbusmock-0.26.1 (Python module). Fixes #16174.

    • [bdubbs] - Update to nghttp2-1.47.0. Fixes #16164.

    • [bdubbs] - Update to sqlite-autoconf-3380000 (3.38.0). Fixes #16159.

    • [bdubbs] - Update to unrar-6.1.6. Fixes #16158.

    • [bdubbs] - Update to gegl-0.4.36. Fixes #16154.

    • [bdubbs] - Update to babl-0.1.90. Fixes #16153.

  • March 6th, 2022

    • [pierre] - Update to upower-0.99.16. Fixes #16168.

    • [pierre] - Update to bubblewrap-0.6.1. Fixes #16169.

    • [pierre] - Update to accountsservice-22.08.8. Fixes #16181.

    • [pierre] - Update to wget-1.21.3. Fixes #16176.

    • [pierre] - Update to smartmontools-7.3. Fixes #16182.

    • [pierre] - Update to openssh-8.9p1 with ssh-askpass. Fixes #16163.

    • [pierre] - Update to mesa-21.3.7. Fixes #16162.

    • [pierre] - Update to graphviz-3.0.0. Fixes #16178.

    • [pierre] - Update to libjpeg-turbo-2.1.3. Fixes #16173.

    • [xry111] - Download polkit from FDO GitLab and run its test suite.

    • [xry111] - Update to JS-91.6.0. Fixes #15368.

    • [xry111] - Add polkit-0.120 patch for JS-91. Addresses #15368.

    • [xry111] - Update to Gjs-1.71.90. Addresses #15368.

  • March 5th, 2022

    • [renodr] - Update to Business-ISSN-1.005 (Perl Module). Fixes #16140.

    • [renodr] - Update to asciidoc-10.1.4. Fixes #16134.

    • [renodr] - Update to lxml-4.8.0. Fixes #16135.

    • [renodr] - Update to Mercurial-6.1. Fixes #16142.

  • March 3rd, 2022

    • [renodr] - Update to seamonkey-2.53.11 (Security Update). Fixes #16185.

    • [renodr] - Update to flac-1.3.4 (Security Update). Fixes #16148.

    • [renodr] - Update to cyrus-sasl-2.1.28 (Security Update). Fixes #16160.

    • [renodr] - Fix CVE-2021-4115 in Polkit. Fixes #16151.

    • [bdubbs] - Update to icewm-2.9.6. Fixes #16166.

    • [bdubbs] - Update to xterm-371. Fixes #16171.

    • [bdubbs] - Update to xf86-video-amdgpu-22.0.0 (Xorg driver). Fixes #16165.

    • [bdubbs] - Update to libva-2.14.0 (Xorg driver). Fixes #16152.

    • [bdubbs] - Update to libinput 1.20.0 (Xorg driver). Fixes #16149.

    • [bdubbs] - Update to MarkupSafe-2.1.0 (Python module). Fixes #16141.

  • March 2nd, 2022

    • [xry111] - Update to vim-8.2.4489 (security fixes). Sync with LFS.

    • [xry111] - Update to dbus-1.14.0. Fixes #16172.

  • March 1st, 2022

    • [bdubbs] - Release of BLFS-11.1.

Mailing Lists

The linuxfromscratch.org server is hosting a number of mailing lists that are used for the development of the BLFS book. These lists include, among others, the main development and support lists.

For more information regarding which lists are available, how to subscribe to them, archive locations, etc., visit https://www.linuxfromscratch.org/mail.html.

BLFS Wiki

The BLFS Project has created a Wiki for users to comment on pages and instructions at https://wiki.linuxfromscratch.org/blfs/wiki. Comments are welcome from all users.

The following are the rules for posting:

  • Users must register and log in to edit a page.

  • Suggestions to change the book should be made by creating a new ticket, not by making comments in the Wiki.

  • Questions with your specific installation problems should be made by subscribing and mailing to the BLFS Support Mailing List at mailto:blfs-support AT linuxfromscratch D0T org.

  • Discussions of build instructions should be made by subscribing and mailing to the BLFS Development List at mailto:blfs-dev AT linuxfromscratch D0T org.

  • Inappropriate material will be removed.

Asking for Help and the FAQ

If you encounter a problem while using this book, and your problem is not listed in the FAQ (https://www.linuxfromscratch.org/faq), you will find that most of the people on Internet Relay Chat (IRC) and on the mailing lists are willing to help you. An overview of the LFS mailing lists can be found in Mailing lists. To assist us in diagnosing and solving your problem, include as much relevant information as possible in your request for help.

Things to Check Prior to Asking

Before asking for help, you should review the following items:

  • Is the hardware support compiled into the kernel or available as a module to the kernel? If it is a module, is it configured properly in modprobe.conf and has it been loaded? You should use lsmod as the root user to see if it's loaded. Check the sys.log file or run modprobe <driver> to review any error message. If it loads properly, you may need to add the modprobe command to your boot scripts.

  • Are your permissions properly set, especially for devices? LFS uses groups to make these settings easier, but it also adds the step of adding users to groups to allow access. A simple usermod -G audio <user> may be all that's necessary for that user to have access to the sound system. Any question that starts out with It works as root, but not as ... requires a thorough review of permissions prior to asking.

  • BLFS liberally uses /opt/<package>. The main objection to this centers around the need to expand your environment variables for each package placed there (e.g., PATH=$PATH:/opt/kde/bin). In most cases, the package instructions will walk you through the changes, but some will not. The section called Going Beyond BLFS is available to help you check.

Things to Mention

Apart from a brief explanation of the problem you're having, the essential things to include in your request are:

  • the version of the book you are using (being r11.0-1090),

  • the package or section giving you problems,

  • the exact error message or symptom you are receiving,

  • whether you have deviated from the book or LFS at all,

  • if you are installing a BLFS package on a non-LFS system.

(Note that saying that you've deviated from the book doesn't mean that we won't help you. It'll just help us to see other possible causes of your problem.)

Expect guidance instead of specific instructions. If you are instructed to read something, please do so. It generally implies that the answer was way too obvious and that the question would not have been asked if a little research was done prior to asking. The volunteers in the mailing list prefer not to be used as an alternative to doing reasonable research on your end. In addition, the quality of your experience with BLFS is also greatly enhanced by this research, and the quality of volunteers is enhanced because they don't feel that their time has been abused, so they are far more likely to participate.

An excellent article on asking for help on the Internet in general has been written by Eric S. Raymond. It is available online at http://www.catb.org/~esr/faqs/smart-questions.html. Read and follow the hints in that document and you are much more likely to get a response to start with and also to get the help you actually need.

Credits

Many people have contributed both directly and indirectly to BLFS. This page lists all of those we can think of. We may well have left people out and if you feel this is the case, drop us a line. Many thanks to all of the LFS community for their assistance with this project.

Current Editors

  • Bruce Dubbs

  • Pierre Labastie

  • DJ Lucas

  • Ken Moffat

  • Douglas Reno

Contributors and Past Editors

The list of contributors is far too large to provide detailed information about the contributions for each contributor. Over the years, the following individuals have provided significant inputs to the book:

  • Timothy Bauscher

  • Daniel Bauman

  • Jeff Bauman

  • Andy Benton

  • Wayne Blaszczyk

  • Paul Campbell

  • Nathan Coulson

  • Jeroen Coumans

  • Guy Dalziel

  • Robert Daniels

  • Richard Downing

  • Manuel Canales Esparcia

  • Jim Gifford

  • Manfred Glombowski

  • Ag Hatzimanikas

  • Mark Hymers

  • James Iwanek

  • David Jensen

  • Jeremy Jones

  • Seth Klein

  • Alex Kloss

  • Eric Konopka

  • Larry Lawrence

  • Chris Lynn

  • Andrew McMurry

  • Randy McMurchy

  • Denis Mugnier

  • Billy O'Connor

  • Fernando de Oliveira

  • Alexander Patrakov

  • Olivier Peres

  • Andreas Pedersen

  • Henning Rohde

  • Matt Rogers

  • James Robertson

  • Henning Rohde

  • Chris Staub

  • Jesse Tie-Ten-Quee

  • Ragnar Thomsen

  • Thomas Trepl

  • Tushar Teredesai

  • Jeremy Utley

  • Zack Winkles

  • Christian Wurst

  • Igor Živković

General Acknowledgments

  • Fernando Arbeiza

  • Miguel Bazdresch

  • Gerard Beekmans

  • Oliver Brakmann

  • Jeremy Byron

  • Ian Chilton

  • David Ciecierski

  • Jim Harris

  • Lee Harris

  • Marc Heerdink

  • Steffen Knollmann

  • Eric Konopka

  • Scot McPherson

  • Ted Riley

Contact Information

Please direct your emails to one of the BLFS mailing lists. See Mailing lists for more information on the available mailing lists.

Chapter 2. Important Information

This chapter is used to explain some of the policies used throughout the book, to introduce important concepts and to explain some issues you may see with some of the included packages.

Notes on Building Software

Those people who have built an LFS system may be aware of the general principles of downloading and unpacking software. Some of that information is repeated here for those new to building their own software.

Each set of installation instructions contains a URL from which you can download the package. The patches; however, are stored on the LFS servers and are available via HTTP. These are referenced as needed in the installation instructions.

While you can keep the source files anywhere you like, we assume that you have unpacked the package and changed into the directory created by the unpacking process (the 'build' directory). We also assume you have uncompressed any required patches and they are in the directory immediately above the 'build' directory.

We can not emphasize strongly enough that you should start from a clean source tree each time. This means that if you have had an error during configuration or compilation, it's usually best to delete the source tree and re-unpack it before trying again. This obviously doesn't apply if you're an advanced user used to hacking Makefiles and C code, but if in doubt, start from a clean tree.

Building Software as an Unprivileged (non-root) User

The golden rule of Unix System Administration is to use your superpowers only when necessary. Hence, BLFS recommends that you build software as an unprivileged user and only become the root user when installing the software. This philosophy is followed in all the packages in this book. Unless otherwise specified, all instructions should be executed as an unprivileged user. The book will advise you on instructions that need root privileges.

Unpacking the Software

If a file is in .tar format and compressed, it is unpacked by running one of the following commands:

tar -xvf filename.tar.gz
tar -xvf filename.tgz
tar -xvf filename.tar.Z
tar -xvf filename.tar.bz2

Note

You may omit using the v parameter in the commands shown above and below if you wish to suppress the verbose listing of all the files in the archive as they are extracted. This can help speed up the extraction as well as make any errors produced during the extraction more obvious to you.

You can also use a slightly different method:

bzcat filename.tar.bz2 | tar -xv

Finally, you sometimes need to be able to unpack patches which are generally not in .tar format. The best way to do this is to copy the patch file to the parent of the 'build' directory and then run one of the following commands depending on whether the file is a .gz or .bz2 file:

gunzip -v patchname.gz
bunzip2 -v patchname.bz2

Verifying File Integrity

Generally, to verify that the downloaded file is complete, many package maintainers also distribute md5sums of the files. To verify the md5sum of the downloaded files, download both the file and the corresponding md5sum file to the same directory (preferably from different on-line locations), and (assuming file.md5sum is the md5sum file downloaded) run the following command:

md5sum -c file.md5sum

If there are any errors, they will be reported. Note that the BLFS book includes md5sums for all the source files also. To use the BLFS supplied md5sums, you can create a file.md5sum (place the md5sum data and the exact name of the downloaded file on the same line of a file, separated by white space) and run the command shown above. Alternately, simply run the command shown below and compare the output to the md5sum data shown in the BLFS book.

md5sum <name_of_downloaded_file>

MD5 is not cryptographically secure, so the md5sums are only provided for detecting unmalicious changes to the file content. For example, an error or truncation introduced during network transfer, or a stealth update to the package from the upstream (updating the content of a released tarball instead of making a new release properly).

There is no 100% secure way to make sure the genuity of the source files. Assuming the upstream is managing their website correctly (the private key is not leaked and the domain is not hijacked), and the trust anchors have been set up correctly using make-ca-1.10 on the BLFS system, we can reasonably trust download URLs to the upstream official website with https protocol. Note that BLFS book itself is published on a website with https, so you should already have some confidence in https protocol or you wouldn't trust the book content.

If the package is downloaded from an unofficial location (for example a local mirror), checksums generated by cryptographically secure digest algorithms (for example SHA256) can be used to verify the genuity of the package. Download the checksum file from the upstream official website (or somewhere you can trust) and compare the checksum of the package from unofficial location with it. For example, SHA256 checksum can be checked with the command:

Note

If the checksum and the package are downloaded from the same untrusted location, you won't gain security enhancement by verifying the package with the checksum. The attacker can fake the checksum as well as compromising the package itself.

sha256sum -c file.sha256sum

If GnuPG-2.3.6 is installed, you can also verify the genuity of the package with a GPG signature. Import the upstream GPG public key with:

gpg --recv-key keyID

keyID should be replaced with the key ID from somewhere you can trust (for example, copy it from the upstream official website using https). Now you can verify the signature with:

gpg --recv-key file.sig file

The advantage of GnuPG signature is, once you imported a public key which can be trusted, you can download both the package and its signature from the same unofficial location and verify them with the public key. So you won't need to connect to the official upstream website to retrieve a checksum for each new release. You only need to update the public key if it's expired or revoked.

Creating Log Files During Installation

For larger packages, it is convenient to create log files instead of staring at the screen hoping to catch a particular error or warning. Log files are also useful for debugging and keeping records. The following command allows you to create an installation log. Replace <command> with the command you intend to execute.

( <command> 2>&1 | tee compile.log && exit $PIPESTATUS )

2>&1 redirects error messages to the same location as standard output. The tee command allows viewing of the output while logging the results to a file. The parentheses around the command run the entire command in a subshell and finally the exit $PIPESTATUS command ensures the result of the <command> is returned as the result and not the result of the tee command.

Using Multiple Processors

For many modern systems with multiple processors (or cores) the compilation time for a package can be reduced by performing a "parallel make" by either setting an environment variable or telling the make program how many processors are available. For instance, a Core2Duo can support two simultaneous processes with:

export MAKEFLAGS='-j2'

or just building with:

make -j2

If you have applied the optional sed when building ninja in LFS, you can use:

export NINJAJOBS=2

when a package uses ninja, or just:

ninja -j2

but for ninja, the default number of jobs is <N>+2, where <N> is the number of processors available, so that using the above commands is rather for limiting the number of jobs (see below for why this could be necessary).

Generally the number of processes should not exceed the number of cores supported by the CPU. To list the processors on your system, issue: grep processor /proc/cpuinfo.

In some cases, using multiple processes may result in a 'race' condition where the success of the build depends on the order of the commands run by the make program. For instance, if an executable needs File A and File B, attempting to link the program before one of the dependent components is available will result in a failure. This condition usually arises because the upstream developer has not properly designated all the prerequisites needed to accomplish a step in the Makefile.

If this occurs, the best way to proceed is to drop back to a single processor build. Adding '-j1' to a make command will override the similar setting in the MAKEFLAGS environment variable.

Note

When running the package tests or the install portion of the package build process, we do not recommend using an option greater than '-j1' unless specified otherwise. The installation procedures or checks have not been validated using parallel procedures and may fail with issues that are difficult to debug.

Important

Another problem may occur with modern CPU's, which have a lot of cores. Each job started consumes memory, and if the sum of the needed memory for each job exceeds the available memory, you may encounter either an OOM (Out of Memory) kernel interrupt or intense swapping that will slow the build beyond reasonable limits.

Some compilations with g++ may consume up to 2.5 GB of memory, so to be safe, you should restrict the number of jobs to (Total Memory in GB)/2.5, at least for big packages such as LLVM, WebKitGtk, QtWebEngine, or libreoffice.

Automated Building Procedures

There are times when automating the building of a package can come in handy. Everyone has their own reasons for wanting to automate building, and everyone goes about it in their own way. Creating Makefiles, Bash scripts, Perl scripts or simply a list of commands used to cut and paste are just some of the methods you can use to automate building BLFS packages. Detailing how and providing examples of the many ways you can automate the building of packages is beyond the scope of this section. This section will expose you to using file redirection and the yes command to help provide ideas on how to automate your builds.

File Redirection to Automate Input

You will find times throughout your BLFS journey when you will come across a package that has a command prompting you for information. This information might be configuration details, a directory path, or a response to a license agreement. This can present a challenge to automate the building of that package. Occasionally, you will be prompted for different information in a series of questions. One method to automate this type of scenario requires putting the desired responses in a file and using redirection so that the program uses the data in the file as the answers to the questions.

Building the CUPS package is a good example of how redirecting a file as input to prompts can help you automate the build. If you run the test suite, you are asked to respond to a series of questions regarding the type of test to run and if you have any auxiliary programs the test can use. You can create a file with your responses, one response per line, and use a command similar to the one shown below to automate running the test suite:

make check < ../cups-1.1.23-testsuite_parms

This effectively makes the test suite use the responses in the file as the input to the questions. Occasionally you may end up doing a bit of trial and error determining the exact format of your input file for some things, but once figured out and documented you can use this to automate building the package.

Using yes to Automate Input

Sometimes you will only need to provide one response, or provide the same response to many prompts. For these instances, the yes command works really well. The yes command can be used to provide a response (the same one) to one or more instances of questions. It can be used to simulate pressing just the Enter key, entering the Y key or entering a string of text. Perhaps the easiest way to show its use is in an example.

First, create a short Bash script by entering the following commands:

cat > blfs-yes-test1 << "EOF"
#!/bin/bash

echo -n -e "\n\nPlease type something (or nothing) and press Enter ---> "

read A_STRING

if test "$A_STRING" = ""; then A_STRING="Just the Enter key was pressed"
else A_STRING="You entered '$A_STRING'"
fi

echo -e "\n\n$A_STRING\n\n"
EOF
chmod 755 blfs-yes-test1

Now run the script by issuing ./blfs-yes-test1 from the command line. It will wait for a response, which can be anything (or nothing) followed by the Enter key. After entering something, the result will be echoed to the screen. Now use the yes command to automate the entering of a response:

yes | ./blfs-yes-test1

Notice that piping yes by itself to the script results in y being passed to the script. Now try it with a string of text:

yes 'This is some text' | ./blfs-yes-test1

The exact string was used as the response to the script. Finally, try it using an empty (null) string:

yes '' | ./blfs-yes-test1

Notice this results in passing just the press of the Enter key to the script. This is useful for times when the default answer to the prompt is sufficient. This syntax is used in the Net-tools instructions to accept all the defaults to the many prompts during the configuration step. You may now remove the test script, if desired.

File Redirection to Automate Output

In order to automate the building of some packages, especially those that require you to read a license agreement one page at a time, requires using a method that avoids having to press a key to display each page. Redirecting the output to a file can be used in these instances to assist with the automation. The previous section on this page touched on creating log files of the build output. The redirection method shown there used the tee command to redirect output to a file while also displaying the output to the screen. Here, the output will only be sent to a file.

Again, the easiest way to demonstrate the technique is to show an example. First, issue the command:

ls -l /usr/bin | more

Of course, you'll be required to view the output one page at a time because the more filter was used. Now try the same command, but this time redirect the output to a file. The special file /dev/null can be used instead of the filename shown, but you will have no log file to examine:

ls -l /usr/bin | more > redirect_test.log 2>&1

Notice that this time the command immediately returned to the shell prompt without having to page through the output. You may now remove the log file.

The last example will use the yes command in combination with output redirection to bypass having to page through the output and then provide a y to a prompt. This technique could be used in instances when otherwise you would have to page through the output of a file (such as a license agreement) and then answer the question of do you accept the above?. For this example, another short Bash script is required:

cat > blfs-yes-test2 << "EOF"
#!/bin/bash

ls -l /usr/bin | more

echo -n -e "\n\nDid you enjoy reading this? (y,n) "

read A_STRING

if test "$A_STRING" = "y"; then A_STRING="You entered the 'y' key"
else A_STRING="You did NOT enter the 'y' key"
fi

echo -e "\n\n$A_STRING\n\n"
EOF
chmod 755 blfs-yes-test2

This script can be used to simulate a program that requires you to read a license agreement, then respond appropriately to accept the agreement before the program will install anything. First, run the script without any automation techniques by issuing ./blfs-yes-test2.

Now issue the following command which uses two automation techniques, making it suitable for use in an automated build script:

yes | ./blfs-yes-test2 > blfs-yes-test2.log 2>&1

If desired, issue tail blfs-yes-test2.log to see the end of the paged output, and confirmation that y was passed through to the script. Once satisfied that it works as it should, you may remove the script and log file.

Finally, keep in mind that there are many ways to automate and/or script the build commands. There is not a single correct way to do it. Your imagination is the only limit.

Dependencies

For each package described, BLFS lists the known dependencies. These are listed under several headings, whose meaning is as follows:

  • Required means that the target package cannot be correctly built without the dependency having first been installed.

  • Recommended means that BLFS strongly suggests this package is installed first for a clean and trouble-free build, that won't have issues either during the build process, or at run-time. The instructions in the book assume these packages are installed. Some changes or workarounds may be required if these packages are not installed.

  • Optional means that this package might be installed for added functionality. Often BLFS will describe the dependency to explain the added functionality that will result.

Using the Most Current Package Sources

On occasion you may run into a situation in the book when a package will not build or work properly. Though the Editors attempt to ensure that every package in the book builds and works properly, sometimes a package has been overlooked or was not tested with this particular version of BLFS.

If you discover that a package will not build or work properly, you should see if there is a more current version of the package. Typically this means you go to the maintainer's web site and download the most current tarball and attempt to build the package. If you cannot determine the maintainer's web site by looking at the download URLs, use Google and query the package's name. For example, in the Google search bar type: 'package_name download' (omit the quotes) or something similar. Sometimes typing: 'package_name home page' will result in you finding the maintainer's web site.

Stripping One More Time

Warning

If you did not strip programs and libraries in LFS, the following will probably make your system unusable. To avoid that, run the instructions at ../../../../lfs/view/development/chapter08/strippingagain.html instead. After the critical files are stripped using those instructions, the instructions below can be run any time new packages are installed.

In LFS, stripping of debugging symbols was discussed a couple of times. When building BLFS packages, there are generally no special instructions that discuss stripping again. It is probably not a good idea to strip an executable or a library while it is in use, so exiting any windowing environment is a good idea. Then you can do:

find /usr/{bin,lib,sbin} \
    -type f \( -name \*.so* -a ! -name \*dbg \) \
    -exec strip --strip-unneeded {} \;

If you install programs in other directories such as /opt or /usr/local, you may want to strip the files there too.

For more information on stripping, see http://www.technovelty.org/linux/stripping-shared-libraries.html.

Working with different build systems

There are now three different build systems in common use for converting C or C++ source code into compiled programs or libraries and their details (particularly, finding out about available options and their default values) differ. It may be easiest to understand the issues caused by some choices (typically slow execution or unexpected use of, or omission of, optimizatons) by starting with the CFLAGS and CXXFLAGS environment variables. There are also some programs which use rust.

Most LFS and BLFS builders are probably aware of the basics of CFLAGS and CXXFLAGS for altering how a program is compiled. Typically, some form of optimization is used by upstream developers (-O2 or -O3), sometimes with the creation of debug symbols (-g), as defaults.

If there are contradictory flags (e.g. multiple different -O values), the last value will be used. Sometimes this means that flags specified in environment variables will be picked up before values hardcoded in the Makefile, and therefore ignored. For example, where a user specifies '-O2' and that is followed by '-O3' the build will use '-O3'.

There are various other things which can be passed in CFLAGS or CXXFLAGS, such as forcing compilation for a specific microarchitecture (e.g. -march=amdfam10, -march=native) or specifying a specific standard for C or C++ (-std=c++17 for example). But one thing which has now come to light is that programmers might include debug assertions in their code, expecting them to be disabled in releases by using -DNDEBUG. Specifically, if Mesa-21.3.7 is built with these assertions enabled, some activities such as loading levels of games can take extremely long times, even on high-class video cards.

Autotools with Make

This combination is often described as 'CMMI' (configure, make, make install) and is used here to also cover the few packages which have a configure script that is not generated by autotools.

Sometimes running ./configure --help will produce useful options about switches which might be used. At other times, after looking at the output from configure you may need to look at the details of the script to find out what it was actually searching for.

Many configure scripts will pick up any CFLAGS or CXXFLAGS from the environment, but CMMI packages vary about how these will be mixed with any flags which would otherwise be used (variously: ignored, used to replace the programmer's suggestion, used before the programmer's suggestion, or used after the programmer's suggestion).

In most CMMI packages, running 'make' will list each command and run it, interspersed with any warnings. But some packages try to be 'silent' and only show which file they are compiling or linking instead of showing the command line. If you need to inspect the command, either because of an error, or just to see what options and flags are being used, adding 'V=1' to the make invocation may help.

CMake

CMake works in a very different way, and it has two backends which can be used on BLFS: 'make' and 'ninja'. The default backend is make, but ninja can be faster on large packages with multiple processors. To use ninja, specify '-G Ninja' in the cmake command. However, there are some packages which create fatal errors in their ninja files but build successfully using the default of Unix Makefiles.

The hardest part of using CMake is knowing what options you might wish to specify. The only way to get a list of what the package knows about is to run cmake -LAH and look at the output for that default configuration.

Perhaps the most-important thing about CMake is that it has a variety of CMAKE_BUILD_TYPE values, and these affect the flags. The default is that this is not set and no flags are generated. Any CFLAGS or CXXFLAGS in the environment will be used. If the programmer has coded any debug assertions, those will be enabled unless -DNDEBUG is used. The following CMAKE_BUILD_TYPE values will generate the flags shown, and these will come after any flags in the environment and therefore take precedence.

  • Debug : '-g'

  • Release : '-O3 -DNDEBUG'

  • RelWithDebInfo : '-O2 -g -DNDEBUG'

  • MinSizeRel : '-Os -DNDEBUG'

CMake tries to produce quiet builds. To see the details of the commands which are being run, use 'make VERBOSE=1' or 'ninja -v'.

Meson

Meson has some similarities to CMake, but many differences. To get details of the defines that you may wish to change you can look at meson_options.txt which is usually in the top-level directory.

If you have already configured the package by running meson and now wish to change one or more settings, you can either remove the build directory, recreate it, and use the altered options, or within the build directory run meson configure, e.g. to set an option:

meson configure -D<some_option>=true

If you do that, the file meson-private/cmd_line.txt will show the last commands which were used.

Meson provides the following buildtype values, and the flags they enable come after any flags supplied in the environment and therefore take precedence.

  • plain : no added flags. This is for distributors to supply their own CLFAGS, CXXFLAGS and LDFLAGS. There is no obvious reason to use this in BLFS.

  • debug : '-g' - this is the default if nothing is specified in either meson.build or the command line. However it results large and slow binaries, so we should override it in BLFS.

  • debugoptimized : '-O2 -g' : this is the default specified in meson.build of some packages.

  • release : '-O3 -DNDEBUG' (but occasionally a package will force -O2 here)

Although the 'release' buildtype is described as enabling -DNDEBUG, and all CMake Release builds pass that, it has so far only been observed (in verbose builds) for Mesa-21.3.7. That suggests that it might only be used when there are debug assertions present.

The -DNDEBUG flag can also be provided by passing -Db_ndebug=true.

To see the details of the commands which are being run in a package using meson, use 'ninja -v'.

Rustc and Cargo

Most released rustc programs are provided as crates (source tarballs) which will query a server to check current versions of dependencies and then download them as necessary. These packages are built using cargo --release. In theory, you can manipulate the RUSTFLAGS to change the optimize-level (default is 3, like -O3, e.g. -Copt-level=3) or to force it to build for the machine it is being compiled on, using -Ctarget-cpu=native but in practice this seems to make no significant difference.

If you find an interesting rustc program which is only provided as unpackaged source, you should at least specify RUSTFLAGS=-Copt-level=2 otherwise it will do an unoptimized compile with debug info and run much slower.

The rust developers seem to assume that everyone will compile on a machine dedicated to producing builds, so by default all CPUs are used. This can often be worked around, either by exporting CARGO_BUILD_JOBS=<N> or passing --jobs <N> to cargo. For compiling rustc itself, specifying --jobs <N> on invocations of x.py (together with the CARGO_BUILD_JOBS environment variable, which looks like a "belt and braces" approach but seems to be necessary) mostly works. The exception is running the tests when building rustc, some of them will nevertheless use all online CPUs, at least as of rustc-1.42.0.

Optimizing the build

Many people will prefer to optimize compiles as they see fit, by providing CFLAGS or CXXFLAGS. For an introduction to the options available with gcc and g++ see https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html and https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html and info gcc.

Some packages default to '-O2 -g', others to '-O3 -g', and if CFLAGS or CXXFLAGS are supplied they might be added to the package's defaults, replace the package's defaults, or even be ignored. There are details on some desktop packages which were mostly current in April 2019 at https://www.linuxfromscratch.org/~ken/tuning/ - in particular, README.txt, tuning-1-packages-and-notes.txt, and tuning-notes-2B.txt. The particular thing to remember is that if you want to try some of the more interesting flags you may need to force verbose builds to confirm what is being used.

Clearly, if you are optimizing your own program you can spend time to profile it and perhaps recode some of it if it is too slow. But for building a whole system that approach is impractical. In general, -O3 usually produces faster programs than -O2. Specifying -march=native is also beneficial, but means that you cannot move the binaries to an incompatible machine - this can also apply to newer machines, not just to older machines. For example programs compiled for 'amdfam10' run on old Phenoms, Kaveris, and Ryzens : but programs compiled for a Kaveri will not run on a Ryzen because certain op-codes are not present. Similarly, if you build for a Haswell not everything will run on a SandyBridge.

There are also various other options which some people claim are beneficial. At worst, you get to recompile and test, and then discover that in your usage the options do not provide a benefit.

If building Perl or Python modules, or Qt packages which use qmake, in general the CFLAGS and CXXFLAGS used are those which were used by those 'parent' packages.

Options for hardening the build

Even on desktop systems, there are still a lot of exploitable vulnerabilities. For many of these, the attack comes via javascript in a browser. Often, a series of vulnerabilities are used to gain access to data (or sometimes to pwn, i.e. own, the machine and install rootkits). Most commercial distros will apply various hardening measures.

For hardening options which are reasonably cheap, there is some discussion in the 'tuning' link above (occasionally, one or more of these options might be inappropriate for a package). These options are -D_FORTIFY_SOURCE=2, -fstack-protector=strong, and (for C++) -D_GLIBCXX_ASSERTIONS. On modern machines these should only have a little impact on how fast things run, and often they will not be noticeable.

In the past, there was Hardened LFS where gcc (a much older version) was forced to use hardening (with options to turn some of it off on a per-package basis. What is being covered here is different - first you have to make sure that the package is indeed using your added flags and not over-riding them.

The main distros use much more, such as RELRO (Relocation Read Only) and perhaps -fstack-clash-protection. You may also encounter the so-called 'userspace retpoline' (-mindirect-branch=thunk etc.) which is the equivalent of the spectre mitigations applied to the linux kernel in late 2018). The kernel mitigations caused a lot of complaints about lost performance, if you have a production server you might wish to consider testing that, along with the other available options, to see if performance is still sufficient.

Whilst gcc has many hardening options, clang/LLVM's strengths lie elsewhere. Some options which gcc provides are said to be less effective in clang/LLVM.

The /usr Versus /usr/local Debate

Should I install XXX in /usr or /usr/local?

This is a question without an obvious answer for an LFS based system.

In traditional Unix systems, /usr usually contains files that come with the system distribution, and the /usr/local tree is free for the local administrator to manage. The only really hard and fast rule is that Unix distributions should not touch /usr/local, except perhaps to create the basic directories within it.

With Linux distributions like Red Hat, Debian, etc., a possible rule is that /usr is managed by the distribution's package system and /usr/local is not. This way the package manager's database knows about every file within /usr.

LFS users build their own system and so deciding where the system ends and local files begin is not straightforward. So the choice should be made in order to make things easier to administer. There are several reasons for dividing files between /usr and /usr/local.

  • On a network of several machines all running LFS, or mixed LFS and other Linux distributions, /usr/local could be used to hold packages that are common between all the computers in the network. It can be NFS mounted or mirrored from a single server. Here local indicates local to the site.

  • On a network of several computers all running an identical LFS system, /usr/local could hold packages that are different between the machines. In this case local refers to the individual computers.

  • Even on a single computer, /usr/local can be useful if you have several distributions installed simultaneously, and want a place to put packages that will be the same on all of them.

  • Or you might regularly rebuild your LFS, but want a place to put files that you don't want to rebuild each time. This way you can wipe the LFS file system and start from a clean partition every time without losing everything.

Some people ask why not use your own directory tree, e.g., /usr/site, rather than /usr/local?

There is nothing stopping you, many sites do make their own trees, however it makes installing new software more difficult. Automatic installers often look for dependencies in /usr and /usr/local, and if the file it is looking for is in /usr/site instead, the installer will probably fail unless you specifically tell it where to look.

What is the BLFS position on this?

All of the BLFS instructions install programs in /usr with optional instructions to install into /opt for some specific packages.

Optional Patches

As you follow the various sections in the book, you will observe that the book occasionally includes patches that are required for a successful and secure installation of the packages. The general policy of the book is to include patches that fall in one of the following criteria:

  • Fixes a compilation problem.

  • Fixes a security problem.

  • Fixes a broken functionality.

In short, the book only includes patches that are either required or recommended. There is a Patches subproject which hosts various patches (including the patches referenced in the books) to enable you to configure your LFS the way you like it.

BLFS Boot Scripts

The BLFS Bootscripts package contains the init scripts that are used throughout the book. It is assumed that you will be using the BLFS Bootscripts package in conjunction with a compatible LFS-Bootscripts package. Refer to ../../../../lfs/view/development/chapter09/bootscripts.html for more information on the LFS-Bootscripts package.

The BLFS Bootscripts package will be used throughout the BLFS book for startup scripts. Unlike LFS, each init script has a separate install target in the BLFS Bootscripts package. It is recommended you keep the package source directory around until completion of your BLFS system. When a script is requested from BLFS Bootscripts, simply change to the directory and as the root user, execute the given make install-<init-script> command. This command installs the init script to its proper location (along with any auxiliary configuration scripts) and also creates the appropriate symlinks to start and stop the service at the appropriate run-level.

Note

You should review each bootscript before installation to ascertain that it satisfies your need. Also verify that the start and stop symlinks it creates match your preferences.

Note

From time to time the bootscripts are updated to accommodate new packages or to make minor corrections. All versions of the bootscripts are located at https://anduin.linuxfromscratch.org/BLFS/blfs-bootscripts/.

About Libtool Archive (.la) files

Files with a .la extension

In LFS we installed a package, libtool, that is used by many packages to build on a variety of Unix platforms. This includes platforms such as AIX, Solaris, IRIX, HP-UX, and Cygwin as well as Linux. The origins of this tool are quite dated. It was intended to manage libraries on systems with less advanced capabilities than a modern Linux system.

On a Linux system, libtool specific files are generally unneeded. Normally libraries are specified in the build process during the link phase. Since a linux system uses the Executable and Linkable Format (ELF) for executables and libraries, information needed to complete the task is embedded in the files. At run time the program loader can query the appropriate files and properly load and execute the program.

The problem is that libtool usually creates one or more text files for package libraries called libtool archives. These small files have a ".la" extension and contain information that is similar to that embedded in the libraries. When building a package that uses libtool, the process automatically looks for these files. If a package is updated and no longer uses the .la file, then the build process can break.

The solution is to remove the .la files. However there is a catch. Some packages, such as ImageMagick-7.1.0-25, use a libtool function, lt_dlopen, to load libraries as needed during execution and resolve their dependencies at run time. In this case, the .la files should remain.

The script below, removes all unneeded .la files and saves them in a directory, /var/local/la-files by default, not in the normal library path. It also searches all pkg-config files (.pc) for embedded references to .la files and fixes them to be conventional library references needed when an application or library is built. It can be run as needed to clean up the directories that may be causing problems.

cat > /usr/sbin/remove-la-files.sh << "EOF"
#!/bin/bash

# /usr/sbin/remove-la-files.sh
# Written for Beyond Linux From Scratch
# by Bruce Dubbs <bdubbs@linuxfromscratch.org>

# Make sure we are running with root privs
if test "${EUID}" -ne 0; then
    echo "Error: $(basename ${0}) must be run as the root user! Exiting..."
    exit 1
fi

# Make sure PKG_CONFIG_PATH is set if discarded by sudo
source /etc/profile

OLD_LA_DIR=/var/local/la-files

mkdir -p $OLD_LA_DIR

# Only search directories in /opt, but not symlinks to directories
OPTDIRS=$(find /opt -mindepth 1 -maxdepth 1 -type d)

# Move any found .la files to a directory out of the way
find /usr/lib $OPTDIRS -name "*.la" ! -path "/usr/lib/ImageMagick*" \
  -exec mv -fv {} $OLD_LA_DIR \;
###############

# Fix any .pc files that may have .la references

STD_PC_PATH='/usr/lib/pkgconfig
             /usr/share/pkgconfig
             /usr/local/lib/pkgconfig
             /usr/local/share/pkgconfig'

# For each directory that can have .pc files
for d in $(echo $PKG_CONFIG_PATH | tr : ' ') $STD_PC_PATH; do

  # For each pc file
  for pc in $d/*.pc ; do
    if [ $pc == "$d/*.pc" ]; then continue; fi

    # Check each word in a line with a .la reference
    for word in $(grep '\.la' $pc); do
      if $(echo $word | grep -q '.la$' ); then
        mkdir -p $d/la-backup
        cp -fv  $pc $d/la-backup

        basename=$(basename $word )
        libref=$(echo $basename|sed -e 's/^lib/-l/' -e 's/\.la$//')

        # Fix the .pc file
        sed -i "s:$word:$libref:" $pc
      fi
    done
  done
done

EOF

chmod +x /usr/sbin/remove-la-files.sh

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/la-files

Libraries: Static or shared?

Libraries: Static or shared?

The original libraries were simply an archive of routines from which the required routines were extracted and linked into the executable program. These are described as static libraries (libfoo.a). On some old operating systems they are the only type available.

On almost all Linux platforms there are also shared libraries (libfoo.so) - one copy of the library is loaded into virtual memory, and shared by all the programs which call any of its functions. This is space efficient.

In the past, essential programs such as a shell were often linked statically so that some form of minimal recovery system would exist even if shared libraries, such as libc.so, became damaged (e.g. moved to lost+found after fsck following an unclean shutdown). Nowadays, most people use an alternative system install or a Live CD if they have to recover. Journaling filesystems also reduce the likelihood of this sort of problem.

Developers, at least while they are developing, often prefer to use static versions of the libraries which their code links to.

Within the book, there are various places where configure switches such as --disable-static are employed, and other places where the possibility of using system versions of libraries instead of the versions included within another package is discussed. The main reason for this is to simplify updates of libraries.

If a package is linked to a dynamic library, updating to a newer library version is automatic once the newer library is installed and the program is (re)started (provided the library major version is unchanged, e.g. going from libfoo.so.2.0 to libfoo.so.2.1. Going to libfoo.so.3 will require recompilation - ldd can be used to find which programs use the old version). If a program is linked to a static library, the program always has to be recompiled. If you know which programs are linked to a particular static library, this is merely an annoyance. But usually you will not know which programs to recompile.

Most libraries are shared, but if you do something unusual, such as moving a shared library to /lib accidentally breaking the .so symlink in /usr/lib while keeping the static library in /lib, the static library will be silently linked into the programs which need it.

One way to identify when a static library is used, is to deal with it at the end of the installation of every package. Write a script to find all the static libraries in /usr/lib or wherever you are installing to, and either move them to another directory so that they are no longer found by the linker, or rename them so that libfoo.a becomes e.g. libfoo.a.hidden. The static library can then be temporarily restored if it is ever needed, and the package needing it can be identified. You may choose to exclude some of the static libraries from glibc if you do this (libc_nonshared.a, libg.a, libieee.a, libm.a, libpthread_nonshared.a, librpcsvc.a, libsupc++.a) to simplify compilation.

If you use this approach, you may discover that more packages than you were expecting use a static library. That was the case with nettle-2.4 in its default static-only configuration: It was required by GnuTLS-3.0.19, but also linked into package(s) which used GnuTLS, such as glib-networking-2.32.3.

Many packages put some of their common functions into a static library which is only used by the programs within the package and, crucially, the library is not installed as a standalone library. These internal libraries are not a problem - if the package has to be rebuilt to fix a bug or vulnerability, nothing else is linked to them.

When BLFS mentions system libraries, it means shared versions of libraries. Some packages such as Firefox-91.9.0 and ghostscript-9.56.1 include many other libraries. When they link to them, they link statically so this also makes the programs bigger. The version they ship is often older than the version used in the system, so it may contain bugs - sometimes developers go to the trouble of fixing bugs in their included libraries, other times they do not.

Sometimes, deciding to use system libraries is an easy decision. Other times it may require you to alter the system version (e.g. for libpng-1.6.37 if used for Firefox-91.9.0). Occasionally, a package ships an old library and can no longer link to the current version, but can link to an older version. In this case, BLFS will usually just use the shipped version. Sometimes the included library is no longer developed separately, or its upstream is now the same as the package's upstream and you have no other packages which will use it. In those cases, you might decide to use the included static library even if you usually prefer to use system libraries.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/libraries

Locale Related Issues

This page contains information about locale related problems and issues. In the following paragraphs you'll find a generic overview of things that can come up when configuring your system for various locales. Many (but not all) existing locale related problems can be classified and fall under one of the headings below. The severity ratings below use the following criteria:

  • Critical: The program doesn't perform its main function. The fix would be very intrusive, it's better to search for a replacement.

  • High: Part of the functionality that the program provides is not usable. If that functionality is required, it's better to search for a replacement.

  • Low: The program works in all typical use cases, but lacks some functionality normally provided by its equivalents.

If there is a known workaround for a specific package, it will appear on that package's page. For the most recent information about locale related issues for individual packages, check the User Notes in the BLFS Wiki.

The Needed Encoding is Not a Valid Option in the Program

Severity: Critical

Some programs require the user to specify the character encoding for their input or output data and present only a limited choice of encodings. This is the case for the -X option in Enscript-1.6.6, the -input-charset option in unpatched Cdrtools-3.02a09, and the character sets offered for display in the menu of Links-2.26. If the required encoding is not in the list, the program usually becomes completely unusable. For non-interactive programs, it may be possible to work around this by converting the document to a supported input character set before submitting to the program.

A solution to this type of problem is to implement the necessary support for the missing encoding as a patch to the original program or to find a replacement.

The Program Assumes the Locale-Based Encoding of External Documents

Severity: High for non-text documents, low for text documents

Some programs, nano-6.3 or JOE-4.6 for example, assume that documents are always in the encoding implied by the current locale. While this assumption may be valid for the user-created documents, it is not safe for external ones. When this assumption fails, non-ASCII characters are displayed incorrectly, and the document may become unreadable.

If the external document is entirely text based, it can be converted to the current locale encoding using the iconv program.

For documents that are not text-based, this is not possible. In fact, the assumption made in the program may be completely invalid for documents where the Microsoft Windows operating system has set de facto standards. An example of this problem is ID3v1 tags in MP3 files (see the BLFS Wiki ID3v1Coding page for more details). For these cases, the only solution is to find a replacement program that doesn't have the issue (e.g., one that will allow you to specify the assumed document encoding).

Among BLFS packages, this problem applies to nano-6.3, JOE-4.6, and all media players except Audacious-4.1.

Another problem in this category is when someone cannot read the documents you've sent them because their operating system is set up to handle character encodings differently. This can happen often when the other person is using Microsoft Windows, which only provides one character encoding for a given country. For example, this causes problems with UTF-8 encoded TeX documents created in Linux. On Windows, most applications will assume that these documents have been created using the default Windows 8-bit encoding.

In extreme cases, Windows encoding compatibility issues may be solved only by running Windows programs under Wine.

The Program Uses or Creates Filenames in the Wrong Encoding

Severity: Critical

The POSIX standard mandates that the filename encoding is the encoding implied by the current LC_CTYPE locale category. This information is well-hidden on the page which specifies the behavior of Tar and Cpio programs. Some programs get it wrong by default (or simply don't have enough information to get it right). The result is that they create filenames which are not subsequently shown correctly by ls, or they refuse to accept filenames that ls shows properly. For the GLib-2.72.1 library, the problem can be corrected by setting the G_FILENAME_ENCODING environment variable to the special "@locale" value. Glib2 based programs that don't respect that environment variable are buggy.

The Zip-3.0 and UnZip-6.0 have this problem because they hard-code the expected filename encoding. UnZip contains a hard-coded conversion table between the CP850 (DOS) and ISO-8859-1 (UNIX) encodings and uses this table when extracting archives created under DOS or Microsoft Windows. However, this assumption only works for those in the US and not for anyone using a UTF-8 locale. Non-ASCII characters will be mangled in the extracted filenames.

The general rule for avoiding this class of problems is to avoid installing broken programs. If this is impossible, the convmv command-line tool can be used to fix filenames created by these broken programs, or intentionally mangle the existing filenames to meet the broken expectations of such programs.

In other cases, a similar problem is caused by importing filenames from a system using a different locale with a tool that is not locale-aware (e.g., OpenSSH-9.0p1). In order to avoid mangling non-ASCII characters when transferring files to a system with a different locale, any of the following methods can be used:

  • Transfer anyway, fix the damage with convmv.

  • On the sending side, create a tar archive with the --format=posix switch passed to tar (this will be the default in a future version of tar).

  • Mail the files as attachments. Mail clients specify the encoding of attached filenames.

  • Write the files to a removable disk formatted with a FAT or FAT32 filesystem.

  • Transfer the files using Samba.

  • Transfer the files via FTP using RFC2640-aware server (this currently means only wu-ftpd, which has bad security history) and client (e.g., lftp).

The last four methods work because the filenames are automatically converted from the sender's locale to UNICODE and stored or sent in this form. They are then transparently converted from UNICODE to the recipient's locale encoding.

The Program Breaks Multibyte Characters or Doesn't Count Character Cells Correctly

Severity: High or critical

Many programs were written in an older era where multibyte locales were not common. Such programs assume that C "char" data type, which is one byte, can be used to store single characters. Further, they assume that any sequence of characters is a valid string and that every character occupies a single character cell. Such assumptions completely break in UTF-8 locales. The visible manifestation is that the program truncates strings prematurely (i.e., at 80 bytes instead of 80 characters). Terminal-based programs don't place the cursor correctly on the screen, don't react to the "Backspace" key by erasing one character, and leave junk characters around when updating the screen, usually turning the screen into a complete mess.

Fixing this kind of problems is a tedious task from a programmer's point of view, like all other cases of retrofitting new concepts into the old flawed design. In this case, one has to redesign all data structures in order to accommodate to the fact that a complete character may span a variable number of "char"s (or switch to wchar_t and convert as needed). Also, for every call to the "strlen" and similar functions, find out whether a number of bytes, a number of characters, or the width of the string was really meant. Sometimes it is faster to write a program with the same functionality from scratch.

Among BLFS packages, this problem applies to xine-ui-0.99.13 and all the shells.

The Package Installs Manual Pages in Incorrect or Non-Displayable Encoding

Severity: Low

LFS expects that manual pages are in the language-specific (usually 8-bit) encoding, as specified on the LFS Man DB page. However, some packages install translated manual pages in UTF-8 encoding (e.g., Shadow, already dealt with), or manual pages in languages not in the table. Not all BLFS packages have been audited for conformance with the requirements put in LFS (the large majority have been checked, and fixes placed in the book for packages known to install non-conforming manual pages). If you find a manual page installed by any of BLFS packages that is obviously in the wrong encoding, please remove or convert it as needed, and report this to BLFS team as a bug.

You can easily check your system for any non-conforming manual pages by copying the following short shell script to some accessible location,

#!/bin/sh
# Begin checkman.sh
# Usage: find /usr/share/man -type f | xargs checkman.sh
for a in "$@"
do
    # echo "Checking $a..."
    # Pure-ASCII manual page (possibly except comments) is OK
    grep -v '.\\"' "$a" | iconv -f US-ASCII -t US-ASCII >/dev/null 2>&1 \
        && continue
    # Non-UTF-8 manual page is OK
    iconv -f UTF-8 -t UTF-8 "$a" >/dev/null 2>&1 || continue
    # Found a UTF-8 manual page, bad.
    echo "UTF-8 manual page: $a" >&2
done
# End checkman.sh

and then issuing the following command (modify the command below if the checkman.sh script is not in your PATH environment variable):

find /usr/share/man -type f | xargs checkman.sh

Note that if you have manual pages installed in any location other than /usr/share/man (e.g., /usr/local/share/man), you must modify the above command to include this additional location.

Going Beyond BLFS

The packages that are installed in this book are only the tip of the iceberg. We hope that the experience you gained with the LFS book and the BLFS book will give you the background needed to compile, install and configure packages that are not included in this book.

When you want to install a package to a location other than /, or /usr, you are installing outside the default environment settings on most machines. The following examples should assist you in determining how to correct this situation. The examples cover the complete range of settings that may need updating, but they are not all needed in every situation.

  • Expand the PATH to include $PREFIX/bin.

  • Expand the PATH for root to include $PREFIX/sbin.

  • Add $PREFIX/lib to /etc/ld.so.conf or expand LD_LIBRARY_PATH to include it. Before using the latter option, check out http://xahlee.org/UnixResource_dir/_/ldpath.html. If you modify /etc/ld.so.conf, remember to update /etc/ld.so.cache by executing ldconfig as the root user.

  • Add $PREFIX/man to /etc/man_db.conf or expand MANPATH.

  • Add $PREFIX/info to INFOPATH.

  • Add $PREFIX/lib/pkgconfig to PKG_CONFIG_PATH. Some packages are now installing .pc files in $PREFIX/share/pkgconfig, so you may have to include this directory also.

  • Add $PREFIX/include to CPPFLAGS when compiling packages that depend on the package you installed.

  • Add $PREFIX/lib to LDFLAGS when compiling packages that depend on a library installed by the package.

If you are in search of a package that is not in the book, the following are different ways you can search for the desired package.

Some general hints on handling new packages:

  • Many of the newer packages follow the ./configure && make && make install process. Help on the options accepted by configure can be obtained via the command ./configure --help.

  • Most of the packages contain documentation on compiling and installing the package. Some of the documents are excellent, some not so excellent. Check out the homepage of the package for any additional and updated hints for compiling and configuring the package.

  • If you are having a problem compiling the package, try searching the LFS archives at https://www.linuxfromscratch.org/search.html for the error or if that fails, try searching Google. Often, a distribution will have already solved the problem (many of them use development versions of packages, so they see the changes sooner than those of us who normally use stable released versions). But be cautious - all builders tend to carry patches which are no longer necessary, and to have fixes which are only required because of their particular choices in how they build a package. You may have to search deeply to find a fix for the package version you are trying to use, or even to find the package (names are sometimes not what you might expect, e.g. ghostscript often has a prefix or a suffix in its name), but the following notes might help, particularly for those who, like the editors, are trying to build the latest versions and encountering problems:

    • Arch http://www.archlinux.org/packages/ - enter the package name in the 'Keywords' box, select the package name, select the 'Source Files' field, and then select the PKGBUILD entry to see how they build this package.

    • Debian http://ftp.uk.debian.org/debian/pool (use your country's version if there is one) - the source will be in .tar.gz tarballs (either the original upstream .orig source, or else a dfsg containing those parts which comply with debian's free software guidelines) accompanied by versioned .diff.gz or .tar.gz additions. These additions often show how the package is built, and may contain patches. In the .diff.gz versions, any patches create files in debian/patches.

    • Fedora package source gets reorganized from time to time. At the moment the package source for rpms is at https://src.fedoraproject.org/projects/rpms/%2A and from there you can try putting a package name in the search box. If the package is found you can look at the files (specfile to control the build, various patches) or the commits. If that fails, you can download an srpm (source rpm) and using rpm2cpio (see the Tip at the bottom of the page). For rpms go to https://dl.fedoraproject.org/pub/fedora/linux/ and then choose which repo you wish to look at - development/rawhide is the latest development, or choose releases for what was shipped in a release, updates for updates to a release, or updates/testing for the latest updates which might work or might have problems.

    • Gentoo - the mirrors for ebuilds and patches seem to be well-hidden, and they change frequently. Also, if you have found a mirror, you need to know which directory the application has been assigned to. The ebuilds themselves can be found at http://packages.gentoo.org/ - use the search field. If there are any patches, a mirror will have them in the files/ directory. Depending on your browser, or the mirror, you might need to download the ebuild to be able to read it. Treat the ebuild as a sort of pseudo-code / shell combination - look in particular for sed commands and patches, or hazard a guess at the meanings of the functions such as dodoc.

    • openSUSE provide a rolling release, some package versions are in http://download.opensuse.org/source/tumbleweed/repo/oss/src/ but others are in ../update/openSUSE-current/src - the source only seems to be available in source rpms.

    • Slackware - the official package browser is currently broken. The site at http://slackbuilds.org/ has current and previous versions in their unofficial repository with links to homepages, downloads, and some individual files, particularly the .SlackBuild files.

    • Ubuntu ftp://ftp.ubuntu.com/ubuntu/pool/ - see the debian notes above.

    If everything else fails, try the blfs-support mailing-list.

Tip

If you have found a package that is only available in .deb or .rpm format, there are two small scripts, rpm2targz and deb2targz that are available at https://anduin.linuxfromscratch.org/BLFS/extras/deb2targz.tar.bz2 and https://anduin.linuxfromscratch.org/BLFS/extras/rpm2targz.tar.bz2 to convert the archives into a simple tar.gz format.

You may also find an rpm2cpio script useful. The Perl version in the linux kernel archives at http://lkml.indiana.edu/hypermail/linux/kernel/0210.2/att-0093/01-rpm2cpio works for most source rpms. The rpm2targz script will use an rpm2cpio script or binary if one is on your path. Note that rpm2cpio will unpack a source rpm in the current directory, giving a tarball, a spec file, and perhaps patches or other files.

Part II. Post LFS Configuration and Extra Software

Chapter 3. After LFS Configuration Issues

The intention of LFS is to provide a basic system which you can build upon. There are several things about tidying up the system which many people wonder about once they have done the base install. We hope to cover these issues in this chapter.

Most people coming from non-Unix like backgrounds to Linux find the concept of text-only configuration files slightly strange. In Linux, just about all configuration is done via the manipulation of text files. The majority of these files can be found in the /etc hierarchy. There are often graphical configuration programs available for different subsystems but most are simply pretty front ends to the process of editing a text file. The advantage of text-only configuration is that you can edit parameters using your favorite text editor, whether that be vim, emacs, or any other editor.

The first task is making a recovery boot device in Creating a Custom Boot Device because it's the most critical need. Hardware issues relevant to firmware and other devices is addressed next. The system is then configured to ease addition of new users, because this can affect the choices you make in the two subsequent topics—The Bash Shell Startup Files and The vimrc Files.

The remaining topics, Customizing your Logon with /etc/issue and Random number generation are then addressed, in that order. They don't have much interaction with the other topics in this chapter.

Creating a Custom Boot Device

Decent Rescue Boot Device Needs

This section is really about creating a rescue device. As the name rescue implies, the host system has a problem, often lost partition information or corrupted file systems, that prevents it from booting and/or operating normally. For this reason, you must not depend on resources from the host being "rescued". To presume that any given partition or hard drive will be available is a risky presumption.

In a modern system, there are many devices that can be used as a rescue device: floppy, cdrom, usb drive, or even a network card. Which one you use depends on your hardware and your BIOS. In the past, a rescue device was thought to be a floppy disk. Today, many systems do not even have a floppy drive.

Building a complete rescue device is a challenging task. In many ways, it is equivalent to building an entire LFS system. In addition, it would be a repetition of information already available. For these reasons, the procedures for a rescue device image are not presented here.

Creating a Rescue Floppy

The software of today's systems has grown large. Linux 2.6 no longer supports booting directly from a floppy. In spite of this, there are solutions available using older versions of Linux. One of the best is Tom's Root/Boot Disk available at http://www.toms.net/rb/. This will provide a minimal Linux system on a single floppy disk and provides the ability to customize the contents of your disk if necessary.

Creating a Bootable CD-ROM

There are several sources that can be used for a rescue CD-ROM. Just about any commercial distribution's installation CD-ROMs or DVDs will work. These include RedHat, Ubuntu, and SuSE. One very popular option is Knoppix.

Also, the LFS Community has developed its own LiveCD available at https://www.linuxfromscratch.org/livecd/. This LiveCD, is no longer capable of building an entire LFS/BLFS system, but is still a good rescue CD-ROM. If you download the ISO image, use xorriso to copy the image to a CD-ROM.

The instructions for using GRUB2 to make a custom rescue CD-ROM are also available in LFS Chapter 10.

Creating a Bootable USB Drive

A USB Pen drive, sometimes called a Thumb drive, is recognized by Linux as a SCSI device. Using one of these devices as a rescue device has the advantage that it is usually large enough to hold more than a minimal boot image. You can save critical data to the drive as well as use it to diagnose and recover a damaged system. Booting such a drive requires BIOS support, but building the system consists of formatting the drive, adding GRUB as well as the Linux kernel and supporting files.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/CreatingaCustomBootDevice

About Console Fonts

An LFS system can be used without a graphical desktop, and unless or until you install a graphical environment you will have to work in the console. Most, if not all, PCs boot with an 8x16 font - whatever the actual screen size. There are a few things you can do to alter the display on the console. Most of them involve changing the font, but the first alters the commandline used by grub.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/aboutconsolefonts

Setting a smaller screen size in grub

Modern screens often have a lot more pixels then the screens used in the past. If your screen is 1600 pixels wide, an 8x16 font will give you 200 columns of text - unless your monitor is enormous, the text will be tiny. One of the ways to work around this is to tell grub to use a smaller size, such as 1024x768 or 800x600 or even 640x480. Even if your screen does not have a 4:3 aspect ratio, this should work.

To try this, you can reboot and edit grub's command-line to insert a 'video=' parameter between the 'root=/dev/sdXn' and 'ro', for example root=/dev/sda2 video=1024x768 ro based on the example in LFS section 10.4.4 : ../../../../lfs/view/development/chapter10/grub.html.

If you decide that you wish to do this, you can then (as the root user) edit /boot/grub/grub.cfg.

Using the standard psf fonts

In LFS the kbd package is used. The fonts it provides are PC Screen Fonts, usually called PSF, and they were installed into /usr/share/consolefonts. Where these include a unicode mapping table, the file suffix is often changed to .psfu although packages such as terminus-font (see below) do not add the 'u'. These fonts are usually compressed with gzip to save space, but that is not essential.

The initial PC text screens had 8 colours, or 16 colours if the bright versions of the original 8 colours were used. A PSF font can include up to 256 characters (technically, glyphs) while allowing 16 colours, or up to 512 characters (in which case, the bright colours will not be available). Clearly, these console fonts cannot be used to display CJK text - that would need thousands of available glyphs.

Some fonts in kbd can cover more than 512 codepoints ('characters'), with varying degrees of fidelity: unicode contains several whitespace codepoints which can all be mapped to a space, varieties of dashes can be mapped to a minus sign, smart quotes can map to the regular ASCII quotes rather than to whatever is used for "codepoint not present or invalid", and those cyrillic or greek letters which look like latin letters can be mapped onto them, so 'A' can also do duty for cyrillic A and greek Alpha, and 'P' can also do duty for cyrillic ER and greek RHO. Unfortunately, where a font has been created from a BDF file (the method in terminus and debian's console-setup ) such mapping of additional codepoints onto an existing glyph is not always done, although the terminus ter-vXXn fonts do this well.

There are over 120 combinations of font and size in kbd: often a font is provided at several character sizes, and sometimes varieties cover different subsets of unicode. Most are 8 pixels wide, in heights from 8 to 16 pixels, but there are a few which are 9 pixels wide, some others which are 12x22, and even one (latarcyrheb-sun32.psfu) which has been scaled up to 16x32. Using a bigger font is another way of making text on a large screen easier to read.

Testing different fonts

You can test fonts as a normal user. If you have a font which has not been installed, you can load it with :

setfont /path/to/yourfont.ext

For the fonts already installed you only need the name, so using gr737a-9x16.psfu.gz as an example:

setfont gr737a-9x16

To see the glyphs in the font, use:

showconsolefont

If the font looks as if it might be useful, you can then go on to test it more thoroughly.

When you find a font which you wish to use, as the root user) edit /etc/sysconfig/console as described in LFS section 9.6.5 ../../../../lfs/view/development/chapter09/usage.html. .

For fonts not supplied with the kbd package you will need to optionally compress it / them with gzip and then install it / them as the root user.

Editing fonts using psf-tools

Although some console fonts are created from BDF files, which is a text format with hex values for the pixels in each row of the character, there are more-modern tools available for editing psf fonts. The psftools package allows you to dump a font to a text representation with a dash for a pixel which is off (black) and a hash for a pixel which is on (white). You can then edit the text file to add more characters, or reshape them, or map extra codepoints onto them, and then create a new psf font with your changes.

Using fonts from Terminus-font

The Terminus Font package provides fixed-width bitmap fonts designed for long (8 hours and more per day) work with computers. Under 'Character variants' on that page is a list of patches (in the alt/ directory). If you are using a graphical browser to look at that page, you can see what the patches do, e.g. 'll2' makes 'l' more visibly different from 'i' and '1'.

By default terminus-fonts will try to create several types of font, and it will fail if bdftopcf from Xorg Applications has not been installed. The configure script is only really useful if you go on to install all the fonts (console and X11 bitmap) to the correct directories, as in a distro. To build only the PSF fonts and their dependencies, run:

make psf

This will create more than 240 ter-*.psf fonts. The 'b' suffix indicates bright, 'n' indicates normal. You can then test them to see if any fit your requirements. Unless you are creating a distro, there seems little point in installing them all.

As an example, to install the last of these fonts, you can gzip it and then as the root user:

install -v -m644 ter-v32n.psf.gz /usr/share/consolefonts

About Firmware

On some recent PCs it can be necessary, or desirable, to load firmware to make them work at their best. There is a directory, /lib/firmware, where the kernel or kernel drivers look for firmware images.

Currently, most firmware can be found at a git repository: http://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/tree/. For convenience, the LFS Project has created a mirror, updated daily, where these firmware files can be accessed via wget or a web browser at https://anduin.linuxfromscratch.org/BLFS/linux-firmware/.

To get the firmware, either point a browser to one of the above repositories and then download the item(s) which you need, or install git-2.36.0 and clone that repository.

For some other firmware, particularly for Intel microcode and certain wifi devices, the needed firmware is not available in the above repository. Some of this will be addressed below, but a search of the Internet for needed firmware is sometimes necessary.

Firmware files are conventionally referred to as blobs because you cannot determine what they will do. Note that firmware is distributed under various different licenses which do not permit disassembly or reverse-engineering.

Firmware for PCs falls into four categories:

  • Updates to the CPU to work around errata, usually referred to as microcode.

  • Firmware for video controllers. On x86 machines this is required for ATI devices (Radeon and AMDGPU chips) and may be useful for Intel (Skylake and later) and Nvidia (Kepler and later) GPUs.

    ATI Radeon and AMGPU devices all require firmware to be able to use KMS (kernel modesetting - the preferred option) as well as for Xorg. For old radeon chips (before the R600), the firmware is still in the kernel source.

    Intel integrated GPUs from Skylake onwards can use firmware for GuC (the Graphics microcontroller), and also for the HuC (HEVC/H265 microcontroller which offloads to the GPU) and the DMC (Display Microcontroller) to provide additional low-power states. The GuC and HuC have had a chequered history in the kernel and updated firmware may be disabled by default, depending on your kernel version. Further details may be found at 01.org and Arch linux.

    Nvidia GPUs from Kepler onwards require signed firmware, otherwise the nouveau driver is unable to provide hardware acceleration. Nvidia has now released firmware up to Turing (most, maybe all, GTX16xx and RTX20xx GPUs) to linux-firmware, and kernels from linux-5.6 should support it, although Mesa support may require a development version until Mesa-20.2 is released. Note that faster clocks than the default are not enabled by the released firmware.

  • Firmware updates for wired network ports. Mostly they work even without the updates, but probably they will work better with the updated firmware. For some modern laptops, firmware for both wired ethernet (e.g. rtl_nic) and also for bluetooth devices (e.g. qca) is required before the wired network can be used.

  • Firmware for other devices, such as wifi. These devices are not required for the PC to boot, but need the firmware before these devices can be used.

Note

Although not needed to load a firmware blob, the following tools may be useful for determining, obtaining, or preparing the needed firmware in order to load it into the system: cpio-2.13, git-2.36.0, pciutils-3.8.0, and Wget-1.21.3

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/aboutfirmware

Microcode updates for CPUs

In general, microcode can be loaded by the BIOS or UEFI, and it might be updated by upgrading to a newer version of those. On linux, you can also load the microcode from the kernel if you are using an AMD family 10h or later processor (first introduced late 2007), or an Intel processor from 1998 and later (Pentium4, Core, etc), if updated microcode has been released. These updates only last until the machine is powered off, so they need to be applied on every boot.

Intel provide updates of their microcode for Skylake and later processors as new vulnerabilities come to light, and have in the past provided updates for processors from SandyBridge onwards, although those are no-longer supported for new fixes. New versions of AMD firmware are rare and usually only apply to a few models, although motherboard manufacturers get extra updates which maybe update microcode along with the changes to support newer CPUs and faster memory.

There are two ways of loading the microcode, described as 'early' and 'late'. Early loading happens before userspace has been started, late loading happens after userspace has started. Not surprisingly, early loading is preferred, (see e.g. an explanatory comment in a kernel commit noted at x86/microcode: Early load microcode on LWN.) Indeed, it is needed to work around one particular erratum in early Intel Haswell processors which had TSX enabled. (See Intel Disables TSX Instructions: Erratum Found in Haswell, Haswell-E/EP, Broadwell-Y .) Without this update glibc can do the wrong thing in uncommon situations.

It is still possible to manually force late loading of microcode, either for testing or to prevent having to reboot. You will need to reconfigure your kernel for either method. The instructions here will create a kernel .config to suite early loading, before forcing late loading to see if there is any microcode. If there is, the instructions then show you how to create an initrd for early loading.

To confirm what processor(s) you have (if more than one, they will be identical) look in /proc/cpuinfo.

If you are creating an initrd to update firmware for different machines, as a distro would do, go down to 'Early loading of microcode' and cat all the Intel blobs to GenuineIntel.bin or cat all the AMD blobs to AuthenticAMD.bin. This creates a larger initrd - for all Intel machines in the 20200609 update the size is 3.0 MB compared to typically 24 KB for one machine.

Intel Microcode for the CPU

The first step is to get the most recent version of the Intel microcode. This must be done by navigating to https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/releases/ and downloading the latest file there. As of this writing the most secure version of the microcode is microcode-20220207. Extract this file in the normal way, the microcode is in the intel-ucode directory, containing various blobs with names in the form XX-YY-ZZ. There are also various other files, and a releasenote.

In the past, intel did not provide any details of which blobs had changed versions, but now the release note details this.

The recent firmware for older processors is provided to deal with vulnerabilities which have now been made public, and for some of these such as Microarchitectural Data Sampling (MDS) you might wish to increase the protection by disabling hyperthreading, or alternatively to disable the kernel's default mitigation because of its impact on compile times. Please read the online documentation at https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/index.html.

Now you need to determine your processor's identity to see if there is any microcode for it. Determine the decimal values of the cpu family, model and stepping by running the following command (it will also report the current microcode version):

head -n7 /proc/cpuinfo

Convert the cpu family, model and stepping to pairs of hexadecimal digits. For a Skylake i3 6100 (described as Intel(R) Core(TM) i3-6100 CPU) the relevant values are cpu family 6, model 94, stepping 3 so in this case the required identification is 06-5e-03. A look at the blobs will show that there is one for this CPU (although for older issues it might have already been applied by the BIOS). If there is a blob for your system then test if it will be applied by copying it (replace <XX-YY-ZZ> by the identifier for your CPU) to where the kernel can find it:

mkdir -pv /lib/firmware/intel-ucode
cp -v intel-ucode/<XX-YY-ZZ> /lib/firmware/intel-ucode

Now that the Intel microcode has been prepared, use the following options when you configure the kernel to load Intel microcode:

General Setup --->
  [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support [CONFIG_BLK_DEV_INITRD]
Processor type and features  --->
  [*] CPU microcode loading support  [CONFIG_MICROCODE]
  [*]      Intel microcode loading support [CONFIG_MICROCODE_INTEL]

After you have successfully booted the new system, force late loading by using the command:

echo 1 > /sys/devices/system/cpu/microcode/reload

Then use the following command to see if anything was loaded: (N.B. the dates when microcode was created may be months ahead of when it was released.)

dmesg | grep -e 'microcode' -e 'Linux version' -e 'Command line'

This old example showing the very old BIOS firmware version was created by temporarily booting without microcode, to show the current Firmware Bug messages, then the late load shows it being updated to revision 0xea which was current at that time.

[    0.000000] Linux version 5.12.8 (lfs@leshp) (gcc (GCC) 11.1.0,
               GNU ld (GNU Binutils) 2.36.1)
               #2 SMP PREEMPT Fri Jun 4 01:25:02 BST 2021
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-5.12.8-sda11 root=/dev/sda11 ro
               resume=/dev/sda10
[    0.028741] [Firmware Bug]: TSC_DEADLINE disabled due to Errata;
               please update microcode to version: 0xb2 (or later)
[    0.115716] SRBDS: Vulnerable: No microcode
[    0.115826] MDS: Vulnerable: Clear CPU buffers attempted, no microcode
[    0.389005] microcode: sig=0x506e3, pf=0x2, revision=0x74
[    0.389030] microcode: Microcode Update Driver: v2.2.
[   70.089502] microcode: updated to revision 0xea, date = 2021-01-25
[   70.089528] x86/CPU: CPU features have changed after loading microcode,
               but might not take effect.
[   70.089530] microcode: Reload completed, microcode revision: 0xea

If the microcode was not updated, there is no new microcode for this system's processor. If it did get updated, you can now proceed to the section called “Early loading of microcode”.

AMD Microcode for the CPU

Begin by downloading a container of firmware for your CPU family from https://anduin.linuxfromscratch.org/BLFS/linux-firmware/amd-ucode/. The family is always specified in hex. Families 10h to 14h (16 to 20) are in microcode_amd.bin. Families 15h, 16h and 17h have their own containers. Create the required directory and put the firmware you downloaded into it as the root user:

mkdir -pv /lib/firmware/amd-ucode
cp -v microcode_amd* /lib/firmware/amd-ucode

When you configure the kernel, use the following options to load AMD microcode:

General Setup --->
  [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support [CONFIG_BLK_DEV_INITRD]
Processor type and features  --->
  [*] CPU microcode loading support  [CONFIG_MICROCODE]
  [*]      AMD microcode loading support [CONFIG_MICROCODE_AMD]

After you have successfully booted the new system, force late loading by using the command:

echo 1 > /sys/devices/system/cpu/microcode/reload

Then use the following command to see if anything was loaded:

dmesg | grep -e 'microcode' -e 'Linux version' -e 'Command line'

This historic example from an old Athlon(tm) II X2 shows it has been updated. At that time, all CPUs were still reported in the microcode details on AMD machines (the current position for AMD machines where newer microcode is available is unknown) :

[    0.000000] Linux version 4.15.3 (ken@testserver) (gcc version 7.3.0 (GCC))
               #1 SMP Sun Feb 18 02:08:12 GMT 2018
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-4.15.3-sda5 root=/dev/sda5 ro
[    0.307619] microcode: CPU0: patch_level=0x010000b6
[    0.307671] microcode: CPU1: patch_level=0x010000b6
[    0.307743] microcode: Microcode Update Driver: v2.2.
[  187.928891] microcode: CPU0: new patch_level=0x010000c8
[  187.928899] microcode: CPU1: new patch_level=0x010000c8

If the microcode was not updated, there is no new microcode for this system's processor. If it did get updated, you can now proceed to the section called “Early loading of microcode”.

Early loading of microcode

If you have established that updated microcode is available for your system, it is time to prepare it for early loading. This requires an additional package, cpio-2.13 and the creation of an initrd which will need to be added to grub.cfg.

It does not matter where you prepare the initrd, and once it is working you can apply the same initrd to later LFS systems or newer kernels on this same machine, at least until any newer microcode is released. Use the following commands:

mkdir -p initrd/kernel/x86/microcode
cd initrd

For an AMD machine, use the following command (replace <MYCONTAINER> with the name of the container for your CPU's family):

cp -v /lib/firmware/amd-ucode/<MYCONTAINER> kernel/x86/microcode/AuthenticAMD.bin

Or for an Intel machine copy the appropriate blob using this command:

cp -v /lib/firmware/intel-ucode/<XX-YY-ZZ> kernel/x86/microcode/GenuineIntel.bin

Now prepare the initrd:

find . | cpio -o -H newc > /boot/microcode.img

You now need to add a new entry to /boot/grub/grub.cfg and here you should add a new line after the linux line within the stanza. If /boot is a separate mountpoint:

initrd /microcode.img

or this if it is not:

initrd /boot/microcode.img

If you are already booting with an initrd (see the section called “About initramfs”), you should run mkinitramfs again after putting the appropriate blob or container into /lib/firmware as explained above. Alternatively, you can have both initrd on the same line, such as initrd /microcode.img /other-initrd.img (adapt that as above if /boot is not a separate mountpoint).

You can now reboot with the added initrd, and then use the same command to check that the early load worked:

dmesg | grep -e 'microcode' -e 'Linux version' -e 'Command line'

If you updated to address vulnerabilities, you can look at /sys/devices/system/cpu/vulnerabilities/ to see what is now reported.

The places and times where early loading happens are very different in AMD and Intel machines. First, an old example of an Intel (Skylake) with early loading:

[    0.000000] microcode: microcode updated early to revision 0xea, date = 2021-01-25
[    0.000000] Linux version 5.12.8 (lfs@leshp) (gcc (GCC) 11.1.0,
               GNU ld (GNU Binutils) 2.36.1) #2 SMP PREEMPT Fri Jun 4 01:25:02 BST 2021
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-5.12.8-sda11 root=/dev/sda11 ro
               resume=/dev/sda10
[    0.381420] microcode: sig=0x506e3, pf=0x2, revision=0xea
[    0.381479] microcode: Microcode Update Driver: v2.2.

A historic AMD example:

[    0.000000] Linux version 4.15.3 (ken@testserver) (gcc version 7.3.0 (GCC))
               #2 SMP Sun Feb 18 02:32:03 GMT 2018
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-4.15.3-sda5 root=/dev/sda5 ro
[    0.307619] microcode: microcode updated early to new patch_level=0x010000c8
[    0.307678] microcode: CPU0: patch_level=0x010000c8
[    0.307723] microcode: CPU1: patch_level=0x010000c8
[    0.307795] microcode: Microcode Update Driver: v2.2.

Firmware for Video Cards

Firmware for ATI video chips (R600 and later)

These instructions do NOT apply to old radeons before the R600 family. For those, the firmware is in the kernel's /lib/firmware/ directory. Nor do they apply if you intend to avoid a graphical setup such as Xorg and are content to use the default 80x25 display rather than a framebuffer.

Early radeon devices only needed a single 2K blob of firmware. Recent devices need several different blobs, and some of them are much bigger. The total size of the radeon firmware directory is over 500K — on a large modern system you can probably spare the space, but it is still redundant to install all the unused files each time you build a system.

A better approach is to install pciutils-3.8.0 and then use lspci to identify which VGA controller is installed.

With that information, check the RadeonFeature page of the Xorg wiki for Decoder ring for engineering vs marketing names to identify the family (you may need to know this for the Xorg driver in BLFS — Southern Islands and Sea Islands use the radeonsi driver) and the specific model.

Now that you know which controller you are using, consult the Radeon page of the Gentoo wiki which has a table listing the required firmware blobs for the various chipsets. Note that Southern Islands and Sea Islands chips use different firmware for kernel 3.17 and later compared to earlier kernels. Identify and download the required blobs then install them:

mkdir -pv /lib/firmware/radeon
cp -v <YOUR_BLOBS> /lib/firmware/radeon

There are actually two ways of installing this firmware. BLFS, in the 'Kernel Configuration for additional firmware' section part of the Xorg ATI Driver-19.1.0 section gives an example of compiling the firmware into the kernel - that is slightly faster to load, but uses more kernel memory. Here we will use the alternative method of making the radeon driver a module. In your kernel config set the following:

Device Drivers --->
  Graphics support --->
      Direct Rendering Manager --->
        [*] Direct Rendering Manager (XFree86 ... support)  [CONFIG_DRM]
      [M] ATI Radeon                                        [CONFIG_DRM_RADEON]

Loading several large blobs from /lib/firmware takes a noticeable time, during which the screen will be blank. If you do not enable the penguin framebuffer logo, or change the console size by using a bigger font, that probably does not matter. If desired, you can slightly reduce the time if you follow the alternate method of specifying 'y' for CONFIG_DRM_RADEON covered in BLFS at the link above — you must specify each needed radeon blob if you do that.

Firmware for Nvidia video chips

Some Nvidia graphics chips need firmware updates to take advantage of all the card's capability. These are generally the GeForce 8, 9, 9300, and 200-900 series chips. For more exact information, see https://nouveau.freedesktop.org/wiki/VideoAcceleration/#firmware.

First, the kernel Nvidia driver must be activated:

Device Drivers --->
  Graphics support --->
      Direct Rendering Manager --->
        <*> Direct Rendering Manager (XFree86 ... support)  [CONFIG_DRM]
      <*/M> Nouveau (NVIDIA) cards                          [CONFIG_DRM_NOUVEAU]

The steps to install the Nvidia firmware are:

wget https://raw.github.com/imirkin/re-vp2/master/extract_firmware.py
wget http://us.download.nvidia.com/XFree86/Linux-x86/325.15/NVIDIA-Linux-x86-325.15.run
sh NVIDIA-Linux-x86-325.15.run --extract-only
python extract_firmware.py
mkdir -p /lib/firmware/nouveau
cp -d nv* vuc-* /lib/firmware/nouveau/

Firmware for Network Interfaces

The kernel likes to load firmware for some network drivers, particularly those from Realtek (the /lib/linux-firmware/rtl_nic/) directory, but they generally appear to work without it. Therefore, you can boot the kernel, check dmesg for messages about this missing firmware, and if necessary download the firmware and put it in the specified directory in /lib/firmware so that it will be found on subsequent boots. Note that with current kernels this works whether or not the driver is compiled in or built as a module, there is no need to build this firmware into the kernel. Here is an example where the R8169 driver has been compiled in but the firmware was not made available. Once the firmware had been provided, there was no mention of it on later boots.

dmesg | grep firmware | grep r8169
[    7.018028] r8169 0000:01:00.0: Direct firmware load for rtl_nic/rtl8168g-2.fw failed with error -2
[    7.018036] r8169 0000:01:00.0 eth0: unable to load firmware patch rtl_nic/rtl8168g-2.fw (-2)

Firmware for Other Devices

Identifying the correct firmware will typically require you to install pciutils-3.8.0, and then use lspci to identify the device. You should then search online to check which module it uses, which firmware, and where to obtain the firmware — not all of it is in linux-firmware.

If possible, you should begin by using a wired connection when you first boot your LFS system. To use a wireless connection you will need to use a network tools such as Wireless Tools-29 and wpa_supplicant-2.10.

Different countries have different regulations on the radio spectrum usage of wireless devices. You can install a firmware to make the wireless devices obey local spectrum regulations, so you won't be inquired by local authority or find your wireless NIC jamming the frequencies of other devices (for example, remote controllers). The regulatory database firmware can be downloaded from https://kernel.org/pub/software/network/wireless-regdb/. To install it, simply extract regulatory.db and regulatory.db.p7s from the tarball into /lib/firmware. The access point would send a country code to your wireless NIC, and wpa_supplicant-2.10 would tell the kernel to load the regulation of this country from regulatory.db, and enforce it.

Firmware may also be needed for other devices such as some SCSI controllers, bluetooth adaptors, or TV recorders. The same principles apply.

About Devices

Although most devices needed by packages in BLFS and beyond are set up properly by udev using the default rules installed by LFS in /etc/udev/rules.d, there are cases where the rules must be modified or augmented.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/aboutdevices

Multiple Sound Cards

If there are multiple sound cards in a system, the "default" sound card becomes random. The method to establish sound card order depends on whether the drivers are modules or not. If the sound card drivers are compiled into the kernel, control is via kernel command line parameters in /boot/grub/grub.cfg. For example, if a system has both an FM801 card and a SoundBlaster PCI card, the following can be appended to the command line:

snd-fm801.index=0 snd-ens1371.index=1

If the sound card drivers are built as modules, the order can be established in the /etc/modprobe.conf file with:

options snd-fm801 index=0
options snd-ens1371 index=1

USB Device Issues

USB devices usually have two kinds of device nodes associated with them.

The first kind is created by device-specific drivers (e.g., usb_storage/sd_mod or usblp) in the kernel. For example, a USB mass storage device would be /dev/sdb, and a USB printer would be /dev/usb/lp0. These device nodes exist only when the device-specific driver is loaded.

The second kind of device nodes (/dev/bus/usb/BBB/DDD, where BBB is the bus number and DDD is the device number) are created even if the device doesn't have a kernel driver. By using these "raw" USB device nodes, an application can exchange arbitrary USB packets with the device, i.e., bypass the possibly-existing kernel driver.

Access to raw USB device nodes is needed when a userspace program is acting as a device driver. However, for the program to open the device successfully, the permissions have to be set correctly. By default, due to security concerns, all raw USB devices are owned by user root and group usb, and have 0664 permissions (the read access is needed, e.g., for lsusb to work and for programs to access USB hubs). Packages (such as SANE and libgphoto2) containing userspace USB device drivers also ship udev rules that change the permissions of the controlled raw USB devices. That is, rules installed by SANE change permissions for known scanners, but not printers. If a package maintainer forgot to write a rule for your device, report a bug to both BLFS (if the package is there) and upstream, and you will need to write your own rule.

There is one situation when such fine-grained access control with pre-generated udev rules doesn't work. Namely, PC emulators such as KVM, QEMU and VirtualBox use raw USB device nodes to present arbitrary USB devices to the guest operating system (note: patches are needed in order to get this to work without the obsolete /proc/bus/usb mount point described below). Obviously, maintainers of these packages cannot know which USB devices are going to be connected to the guest operating system. You can either write separate udev rules for all needed USB devices yourself, or use the default catch-all "usb" group, members of which can send arbitrary commands to all USB devices.

Before Linux-2.6.15, raw USB device access was performed not with /dev/bus/usb/BBB/DDD device nodes, but with /proc/bus/usb/BBB/DDD pseudofiles. Some applications (e.g., VMware Workstation) still use only this deprecated technique and can't use the new device nodes. For them to work, use the "usb" group, but remember that members will have unrestricted access to all USB devices. To create the fstab entry for the obsolete usbfs filesystem:

usbfs  /proc/bus/usb  usbfs  devgid=14,devmode=0660  0  0

Note

Adding users to the "usb" group is inherently insecure, as they can bypass access restrictions imposed through the driver-specific USB device nodes. For instance, they can read sensitive data from USB hard drives without being in the "disk" group. Avoid adding users to this group, if you can.

Udev Device Attributes

Fine-tuning of device attributes such as group name and permissions is possible by creating extra udev rules, matching on something like this. The vendor and product can be found by searching the /sys/devices directory entries or using udevadm info after the device has been attached. See the documentation in the current udev directory of /usr/share/doc for details.

SUBSYSTEM=="usb_device", SYSFS{idVendor}=="05d8", SYSFS{idProduct}=="4002", \
  GROUP:="scanner", MODE:="0660"

Note

The above line is used for descriptive purposes only. The scanner udev rules are put into place when installing SANE-1.0.32.

Devices for Servers

In some cases, it makes sense to disable udev completely and create static devices. Servers are one example of this situation. Does a server need the capability of handling dynamic devices? Only the system administrator can answer that question, but in many cases the answer will be no.

If dynamic devices are not desired, then static devices must be created on the system. In the default configuration, the /etc/rc.d/rcS.d/S10udev boot script mounts a tmpfs partition over the /dev directory. This problem can be overcome by mounting the root partition temporarily:

Warning

If the instructions below are not followed carefully, your system could become unbootable.

mount --bind / /mnt
cp -a /dev/* /mnt/dev
rm /etc/rc.d/rcS.d/{S10udev,S50udev_retry}
umount /mnt

At this point, the system will use static devices upon the next reboot. Create any desired additional devices using mknod.

If you want to restore the dynamic devices, recreate the /etc/rc.d/rcS.d/{S10udev,S50udev_retry} symbolic links and reboot again. Static devices do not need to be removed (console and null are always needed) because they are covered by the tmpfs partition. Disk usage for devices is negligible (about 20–30 bytes per entry.)

Devices for DVD Drives

If the initial boot process does not set up the /dev/dvd device properly, it can be installed using the following modification to the default udev rules. As the root user, run:

sed '1d;/SYMLINK.*cdrom/ a\
KERNEL=="sr0", ENV{ID_CDROM_DVD}=="1", SYMLINK+="dvd", OPTIONS+="link_priority=-100"' \
/lib/udev/rules.d/60-cdrom_id.rules > /etc/udev/rules.d/60-cdrom_id.rules

Configuring for Adding Users

Together, the /usr/sbin/useradd command and /etc/skel directory (both are easy to set up and use) provide a way to assure new users are added to your LFS system with the same beginning settings for things such as the PATH, keyboard processing and other environmental variables. Using these two facilities makes it easier to assure this initial state for each new user added to the system.

The /etc/skel directory holds copies of various initialization and other files that may be copied to the new user's home directory when the /usr/sbin/useradd program adds the new user.

Useradd

The useradd program uses a collection of default values kept in /etc/default/useradd. This file is created in a base LFS installation by the Shadow package. If it has been removed or renamed, the useradd program uses some internal defaults. You can see the default values by running /usr/sbin/useradd -D.

To change these values, simply modify the /etc/default/useradd file as the root user. An alternative to directly modifying the file is to run useradd as the root user while supplying the desired modifications on the command line. Information on how to do this can be found in the useradd man page.

/etc/skel

To get started, create an /etc/skel directory and make sure it is writable only by the system administrator, usually root. Creating the directory as root is the best way to go.

The mode of any files from this part of the book that you put in /etc/skel should be writable only by the owner. Also, since there is no telling what kind of sensitive information a user may eventually place in their copy of these files, you should make them unreadable by "group" and "other".

You can also put other files in /etc/skel and different permissions may be needed for them.

Decide which initialization files should be provided in every (or most) new user's home directory. The decisions you make will affect what you do in the next two sections, The Bash Shell Startup Files and The vimrc Files. Some or all of those files will be useful for root, any already-existing users, and new users.

The files from those sections that you might want to place in /etc/skel include .inputrc, .bash_profile, .bashrc, .bash_logout, .dircolors, and .vimrc. If you are unsure which of these should be placed there, just continue to the following sections, read each section and any references provided, and then make your decision.

You will run a slightly modified set of commands for files which are placed in /etc/skel. Each section will remind you of this. In brief, the book's commands have been written for files not added to /etc/skel and instead just sends the results to the user's home directory. If the file is going to be in /etc/skel, change the book's command(s) to send output there instead and then just copy the file from /etc/skel to the appropriate directories, like /etc, ~ or the home directory of any other user already in the system.

When Adding a User

When adding a new user with useradd, use the -m parameter, which tells useradd to create the user's home directory and copy files from /etc/skel (can be overridden) to the new user's home directory. For example (perform as the root user):

useradd -m <newuser>

About System Users and Groups

Throughout BLFS, many packages install programs that run as daemons or in some way should have a user or group name assigned. Generally these names are used to map a user ID (uid) or group ID (gid) for system use. Generally the specific uid or gid numbers used by these applications are not significant. The exception of course, is that root has a uid and gid of 0 (zero) that is indeed special. The uid values are stored in /etc/passwd and the gid values are found in /etc/group.

Customarily, Unix systems classify users and groups into two categories: system users and regular users. The system users and groups are given low numbers and regular users and groups have numeric values greater than all the system values. The cutoff for these numbers is found in two parameters in the /etc/login.defs configuration file. The default UID_MIN value is 1000 and the default GID_MIN value is 1000. If a specific uid or gid value is not specified when creating a user with useradd or a group with groupadd the values assigned will always be above these cutoff values.

Additionally, the Linux Standard Base recommends that system uid and gid values should be below 100.

Below is a table of suggested uid/gid values used in BLFS beyond those defined in a base LFS installation. These can be changed as desired, but provide a suggested set of consistent values.

Table 3.1. UID/GID Suggested Values

Name uid gid
bin 1
lp 9
adm 16
atd 17 17
messagebus 18 18
lpadmin   19
named 20 20
gdm 21 21
fcron 22 22
systemd-journal 23 23
apache 25 25
smmsp 26 26
polkitd 27 27
rpc 28 28
exim 31 31
postfix 32 32
postdrop 33
sendmail 34
mail 34
vmailman 35 35
news 36 36
kdm 37 37
fetchmail 38
mysql 40 40
postgres 41 41
dovecot 42 42
dovenull 43 43
ftp 45 45
proftpd 46 46
vsftpd 47 47
rsyncd 48 48
sshd 50 50
stunnel 51 51
dhcpcd 52 52
svn 56 56
svntest 57
git 58 58
games 60 60
kvm 61
wireshark 62
lightdm 63 63
sddm 64 64
lightdm 65 65
scanner 70
colord 71 71
systemd-journal-gateway 73 73
systemd-journal-remote 74 74
systemd-journal-upload 75 75
systemd-network 76 76
systemd-resolve 77 77
systemd-timesync 78 78
systemd-coredump 79 79
uuidd 80 80
systemd-oom 81 81
ldap 83 83
avahi 84 84
avahi-autoipd 85 85
netdev 86
ntp 87 87
unbound 88 88
plugdev 90
wheel 97
anonymous 98
nobody 65534
nogroup 65534

The Bash Shell Startup Files

The shell program /bin/bash (hereafter referred to as just "the shell") uses a collection of startup files to help create an environment. Each file has a specific use and may affect login and interactive environments differently. The files in the /etc directory generally provide global settings. If an equivalent file exists in your home directory it may override the global settings.

An interactive login shell is started after a successful login, using /bin/login, by reading the /etc/passwd file. This shell invocation normally reads /etc/profile and its private equivalent ~/.bash_profile (or ~/.profile if called as /bin/sh) upon startup.

An interactive non-login shell is normally started at the command-line using a shell program (e.g., [prompt]$/bin/bash) or by the /bin/su command. An interactive non-login shell is also started with a terminal program such as xterm or konsole from within a graphical environment. This type of shell invocation normally copies the parent environment and then reads the user's ~/.bashrc file for additional startup configuration instructions.

A non-interactive shell is usually present when a shell script is running. It is non-interactive because it is processing a script and not waiting for user input between commands. For these shell invocations, only the environment inherited from the parent shell is used.

The file ~/.bash_logout is not used for an invocation of the shell. It is read and executed when a user exits from an interactive login shell.

Many distributions use /etc/bashrc for system wide initialization of non-login shells. This file is usually called from the user's ~/.bashrc file and is not built directly into bash itself. This convention is followed in this section.

For more information see info bash -- Nodes: Bash Startup Files and Interactive Shells.

Note

Most of the instructions below are used to create files located in the /etc directory structure which requires you to execute the commands as the root user. If you elect to create the files in user's home directories instead, you should run the commands as an unprivileged user.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/bash-shell-startup-files

/etc/profile

Here is a base /etc/profile. This file starts by setting up some helper functions and some basic parameters. It specifies some bash history parameters and, for security purposes, disables keeping a permanent history file for the root user. It also sets a default user prompt. It then calls small, single purpose scripts in the /etc/profile.d directory to provide most of the initialization.

For more information on the escape sequences you can use for your prompt (i.e., the PS1 environment variable) see info bash -- Node: Printing a Prompt.

cat > /etc/profile << "EOF"
# Begin /etc/profile
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>
# modifications by Dagmar d'Surreal <rivyqntzne@pbzpnfg.arg>

# System wide environment variables and startup programs.

# System wide aliases and functions should go in /etc/bashrc.  Personal
# environment variables and startup programs should go into
# ~/.bash_profile.  Personal aliases and functions should go into
# ~/.bashrc.

# Functions to help us manage paths.  Second argument is the name of the
# path variable to be modified (default: PATH)
pathremove () {
        local IFS=':'
        local NEWPATH
        local DIR
        local PATHVARIABLE=${2:-PATH}
        for DIR in ${!PATHVARIABLE} ; do
                if [ "$DIR" != "$1" ] ; then
                  NEWPATH=${NEWPATH:+$NEWPATH:}$DIR
                fi
        done
        export $PATHVARIABLE="$NEWPATH"
}

pathprepend () {
        pathremove $1 $2
        local PATHVARIABLE=${2:-PATH}
        export $PATHVARIABLE="$1${!PATHVARIABLE:+:${!PATHVARIABLE}}"
}

pathappend () {
        pathremove $1 $2
        local PATHVARIABLE=${2:-PATH}
        export $PATHVARIABLE="${!PATHVARIABLE:+${!PATHVARIABLE}:}$1"
}

export -f pathremove pathprepend pathappend

# Set the initial path
export PATH=/usr/bin

# Attempt to provide backward compatibility with LFS earlier than 11
if [ ! -L /bin ]; then
        pathappend /bin
fi

if [ $EUID -eq 0 ] ; then
        pathappend /usr/sbin
        if [ ! -L /sbin ]; then
                pathappend /sbin
        fi
        unset HISTFILE
fi

# Setup some environment variables.
export HISTSIZE=1000
export HISTIGNORE="&:[bf]g:exit"

# Set some defaults for graphical systems
export XDG_DATA_DIRS=${XDG_DATA_DIRS:-/usr/share/}
export XDG_CONFIG_DIRS=${XDG_CONFIG_DIRS:-/etc/xdg/}
export XDG_RUNTIME_DIR=${XDG_RUNTIME_DIR:-/tmp/xdg-$USER}

# Setup a red prompt for root and a green one for users.
NORMAL="\[\e[0m\]"
RED="\[\e[1;31m\]"
GREEN="\[\e[1;32m\]"
if [[ $EUID == 0 ]] ; then
  PS1="$RED\u [ $NORMAL\w$RED ]# $NORMAL"
else
  PS1="$GREEN\u [ $NORMAL\w$GREEN ]\$ $NORMAL"
fi

for script in /etc/profile.d/*.sh ; do
        if [ -r $script ] ; then
                . $script
        fi
done

unset script RED GREEN NORMAL

# End /etc/profile
EOF

The /etc/profile.d Directory

Now create the /etc/profile.d directory, where the individual initialization scripts are placed:

install --directory --mode=0755 --owner=root --group=root /etc/profile.d

/etc/profile.d/bash_completion.sh

Note

Using the bash completion script below is controversial. Not all users like it. It adds many (usually over 1000) lines to the bash environment and makes it difficult to use the 'set' command to examine simple environment variables. Omitting this script does not interfere with the ability of bash to use the tab key for file name completion.

This script imports bash completion scripts, installed by many other BLFS packages, to allow TAB command line completion.

cat > /etc/profile.d/bash_completion.sh << "EOF"
# Begin /etc/profile.d/bash_completion.sh
# Import bash completion scripts

# If the bash-completion package is installed, use its configuration instead
if [ -f /usr/share/bash-completion/bash_completion ]; then

  # Check for interactive bash and that we haven't already been sourced.
  if [ -n "${BASH_VERSION-}" -a -n "${PS1-}" -a -z "${BASH_COMPLETION_VERSINFO-}" ]; then

    # Check for recent enough version of bash.
    if [ ${BASH_VERSINFO[0]} -gt 4 ] || \
       [ ${BASH_VERSINFO[0]} -eq 4 -a ${BASH_VERSINFO[1]} -ge 1 ]; then
       [ -r "${XDG_CONFIG_HOME:-$HOME/.config}/bash_completion" ] && \
            . "${XDG_CONFIG_HOME:-$HOME/.config}/bash_completion"
       if shopt -q progcomp && [ -r /usr/share/bash-completion/bash_completion ]; then
          # Source completion code.
          . /usr/share/bash-completion/bash_completion
       fi
    fi
  fi

else

  # bash-completions are not installed, use only bash completion directory
  if shopt -q progcomp; then
    for script in /etc/bash_completion.d/* ; do
      if [ -r $script ] ; then
        . $script
      fi
    done
  fi
fi

# End /etc/profile.d/bash_completion.sh
EOF

Make sure that the directory exists:

install --directory --mode=0755 --owner=root --group=root /etc/bash_completion.d

For a more complete installation, see https://wiki.linuxfromscratch.org/blfs/wiki/bash-shell-startup-files#bash-completions.

/etc/profile.d/dircolors.sh

This script uses the ~/.dircolors and /etc/dircolors files to control the colors of file names in a directory listing. They control colorized output of things like ls --color. The explanation of how to initialize these files is at the end of this section.

cat > /etc/profile.d/dircolors.sh << "EOF"
# Setup for /bin/ls and /bin/grep to support color, the alias is in /etc/bashrc.
if [ -f "/etc/dircolors" ] ; then
        eval $(dircolors -b /etc/dircolors)
fi

if [ -f "$HOME/.dircolors" ] ; then
        eval $(dircolors -b $HOME/.dircolors)
fi

alias ls='ls --color=auto'
alias grep='grep --color=auto'
EOF

/etc/profile.d/extrapaths.sh

This script adds some useful paths to the PATH and can be used to customize other PATH related environment variables (e.g. LD_LIBRARY_PATH, etc) that may be needed for all users.

cat > /etc/profile.d/extrapaths.sh << "EOF"
if [ -d /usr/local/lib/pkgconfig ] ; then
        pathappend /usr/local/lib/pkgconfig PKG_CONFIG_PATH
fi
if [ -d /usr/local/bin ]; then
        pathprepend /usr/local/bin
fi
if [ -d /usr/local/sbin -a $EUID -eq 0 ]; then
        pathprepend /usr/local/sbin
fi

if [ -d /usr/local/share ]; then
        pathprepend /usr/local/share XDG_DATA_DIRS
fi

# Set some defaults before other applications add to these paths.
pathappend /usr/share/man  MANPATH
pathappend /usr/share/info INFOPATH
EOF

/etc/profile.d/readline.sh

This script sets up the default inputrc configuration file. If the user does not have individual settings, it uses the global file.

cat > /etc/profile.d/readline.sh << "EOF"
# Setup the INPUTRC environment variable.
if [ -z "$INPUTRC" -a ! -f "$HOME/.inputrc" ] ; then
        INPUTRC=/etc/inputrc
fi
export INPUTRC
EOF

/etc/profile.d/umask.sh

Setting the umask value is important for security. Here the default group write permissions are turned off for system users and when the user name and group name are not the same.

cat > /etc/profile.d/umask.sh << "EOF"
# By default, the umask should be set.
if [ "$(id -gn)" = "$(id -un)" -a $EUID -gt 99 ] ; then
  umask 002
else
  umask 022
fi
EOF

/etc/profile.d/i18n.sh

This script sets an environment variable necessary for native language support. A full discussion on determining this variable can be found on the LFS Bash Shell Startup Files page.

cat > /etc/profile.d/i18n.sh << "EOF"
# Set up i18n variables
export LANG=<ll>_<CC>.<charmap><@modifiers>
EOF

Other Initialization Values

Other initialization can easily be added to the profile by adding additional scripts to the /etc/profile.d directory.

/etc/bashrc

Here is a base /etc/bashrc. Comments in the file should explain everything you need.

cat > /etc/bashrc << "EOF"
# Begin /etc/bashrc
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>
# updated by Bruce Dubbs <bdubbs@linuxfromscratch.org>

# System wide aliases and functions.

# System wide environment variables and startup programs should go into
# /etc/profile.  Personal environment variables and startup programs
# should go into ~/.bash_profile.  Personal aliases and functions should
# go into ~/.bashrc

# Provides colored /bin/ls and /bin/grep commands.  Used in conjunction
# with code in /etc/profile.

alias ls='ls --color=auto'
alias grep='grep --color=auto'

# Provides prompt for non-login shells, specifically shells started
# in the X environment. [Review the LFS archive thread titled
# PS1 Environment Variable for a great case study behind this script
# addendum.]

NORMAL="\[\e[0m\]"
RED="\[\e[1;31m\]"
GREEN="\[\e[1;32m\]"
if [[ $EUID == 0 ]] ; then
  PS1="$RED\u [ $NORMAL\w$RED ]# $NORMAL"
else
  PS1="$GREEN\u [ $NORMAL\w$GREEN ]\$ $NORMAL"
fi

unset RED GREEN NORMAL

# End /etc/bashrc
EOF

~/.bash_profile

Here is a base ~/.bash_profile. If you want each new user to have this file automatically, just change the output of the command to /etc/skel/.bash_profile and check the permissions after the command is run. You can then copy /etc/skel/.bash_profile to the home directories of already existing users, including root, and set the owner and group appropriately.

cat > ~/.bash_profile << "EOF"
# Begin ~/.bash_profile
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>
# updated by Bruce Dubbs <bdubbs@linuxfromscratch.org>

# Personal environment variables and startup programs.

# Personal aliases and functions should go in ~/.bashrc.  System wide
# environment variables and startup programs are in /etc/profile.
# System wide aliases and functions are in /etc/bashrc.

if [ -f "$HOME/.bashrc" ] ; then
  source $HOME/.bashrc
fi

if [ -d "$HOME/bin" ] ; then
  pathprepend $HOME/bin
fi

# Having . in the PATH is dangerous
#if [ $EUID -gt 99 ]; then
#  pathappend .
#fi

# End ~/.bash_profile
EOF

~/.profile

Here is a base ~/.profile. The comments and instructions for using /etc/skel for .bash_profile above also apply here. Only the target file names are different.

cat > ~/.profile << "EOF"
# Begin ~/.profile
# Personal environment variables and startup programs.

if [ -d "$HOME/bin" ] ; then
  pathprepend $HOME/bin
fi

# Set up user specific i18n variables
#export LANG=<ll>_<CC>.<charmap><@modifiers>

# End ~/.profile
EOF

~/.bashrc

Here is a base ~/.bashrc.

cat > ~/.bashrc << "EOF"
# Begin ~/.bashrc
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>

# Personal aliases and functions.

# Personal environment variables and startup programs should go in
# ~/.bash_profile.  System wide environment variables and startup
# programs are in /etc/profile.  System wide aliases and functions are
# in /etc/bashrc.

if [ -f "/etc/bashrc" ] ; then
  source /etc/bashrc
fi

# Set up user specific i18n variables
#export LANG=<ll>_<CC>.<charmap><@modifiers>

# End ~/.bashrc
EOF

~/.bash_logout

This is an empty ~/.bash_logout that can be used as a template. You will notice that the base ~/.bash_logout does not include a clear command. This is because the clear is handled in the /etc/issue file.

cat > ~/.bash_logout << "EOF"
# Begin ~/.bash_logout
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>

# Personal items to perform on logout.

# End ~/.bash_logout
EOF

/etc/dircolors

If you want to use the dircolors capability, then run the following command. The /etc/skel setup steps shown above also can be used here to provide a ~/.dircolors file when a new user is set up. As before, just change the output file name on the following command and assure the permissions, owner, and group are correct on the files created and/or copied.

dircolors -p > /etc/dircolors

If you wish to customize the colors used for different file types, you can edit the /etc/dircolors file. The instructions for setting the colors are embedded in the file.

Finally, Ian Macdonald has written an excellent collection of tips and tricks to enhance your shell environment. You can read it online at http://www.caliban.org/bash/index.shtml.

The /etc/vimrc and ~/.vimrc Files

The LFS book installs Vim as its text editor. At this point it should be noted that there are a lot of different editing applications out there including Emacs, nano, Joe and many more. Anyone who has been around the Internet (especially usenet) for a short time will certainly have observed at least one flame war, usually involving Vim and Emacs users!

The LFS book creates a basic vimrc file. In this section you'll find an attempt to enhance this file. At startup, vim reads the global configuration file (/etc/vimrc) as well as a user-specific file (~/.vimrc). Either or both can be tailored to suit the needs of your particular system.

Here is a slightly expanded .vimrc that you can put in ~/.vimrc to provide user specific effects. Of course, if you put it into /etc/skel/.vimrc instead, it will be made available to users you add to the system later. You can also copy the file from /etc/skel/.vimrc to the home directory of users already on the system, such as root. Be sure to set permissions, owner, and group if you do copy anything directly from /etc/skel.

" Begin .vimrc

set columns=80
set wrapmargin=8
set ruler

" End .vimrc

Note that the comment tags are " instead of the more usual # or //. This is correct, the syntax for vimrc is slightly unusual.

Below you'll find a quick explanation of what each of the options in this example file means here:

  • set columns=80: This simply sets the number of columns used on the screen.

  • set wrapmargin=8: This is the number of characters from the right window border where wrapping starts.

  • set ruler: This makes vim show the current row and column at the bottom right of the screen.

More information on the many vim options can be found by reading the help inside vim itself. Do this by typing :help in vim to get the general help, or by typing :help usr_toc.txt to view the User Manual Table of Contents.

Customizing your Logon with /etc/issue

When you first boot up your new LFS system, the logon screen will be nice and plain (as it should be in a bare-bones system). Many people however, will want their system to display some information in the logon message. This can be accomplished using the file /etc/issue.

The /etc/issue file is a plain text file which will also accept certain escape sequences (see below) in order to insert information about the system. There is also the file issue.net which can be used when logging on remotely. ssh however, will only use it if you set the option in the configuration file and will not interpret the escape sequences shown below.

One of the most common things which people want to do is clear the screen at each logon. The easiest way of doing that is to put a "clear" escape sequence into /etc/issue. A simple way of doing this is to issue the command clear > /etc/issue. This will insert the relevant escape code into the start of the /etc/issue file. Note that if you do this, when you edit the file, you should leave the characters (normally '^[[H^[[2J') on the first line alone.

Note

Terminal escape sequences are special codes recognized by the terminal. The ^[ represents an ASCII ESC character. The sequence ESC [ H puts the cursor in the upper left hand corner of the screen and ESC 2 J erases the screen. For more information on terminal escape sequences see http://rtfm.etla.org/xterm/ctlseq.html

The following sequences are recognized by agetty (the program which usually parses /etc/issue). This information is from man agetty where you can find extra information about the logon process.

The issue file can contain certain character sequences to display various information. All issue sequences consist of a backslash (\) immediately followed by one of the letters explained below (so \d in /etc/issue would insert the current date).

b   Insert the baudrate of the current line.
d   Insert the current date.
s   Insert the system name, the name of the operating system.
l   Insert the name of the current tty line.
m   Insert the architecture identifier of the machine, e.g., i686.
n   Insert the nodename of the machine, also known as the hostname.
o   Insert the domainname of the machine.
r   Insert the release number of the kernel, e.g., 2.6.11.12.
t   Insert the current time.
u   Insert the number of current users logged in.
U   Insert the string "1 user" or "<n> users" where <n> is the
    number of current users logged in.
v   Insert the version of the OS, e.g., the build-date etc.

Random Number Generation

The Linux kernel supplies a random number generator which is accessed through /dev/random and /dev/urandom. Programs that utilize the random and urandom devices, such as OpenSSH, will benefit from these instructions.

When a Linux system starts up without much operator interaction, the entropy pool (data used to compute a random number) may be in a fairly predictable state. This creates the real possibility that the number generated at startup may always be the same. In order to counteract this effect, you should carry the entropy pool information across your shut-downs and start-ups.

Install the /etc/rc.d/init.d/random init script included with the blfs-bootscripts-20210826 package.

make install-random

Chapter 4. Security

Security takes many forms in a computing environment. After some initial discussion, this chapter gives examples of three different types of security: access, prevention and detection.

Access for users is usually handled by login or an application designed to handle the login function. In this chapter, we show how to enhance login by setting policies with PAM modules. Access via networks can also be secured by policies set by iptables, commonly referred to as a firewall. The Network Security Services (NSS) and Netscape Portable Runtime (NSPR) libraries can be installed and shared among the many applications requiring them. For applications that don't offer the best security, you can use the Stunnel package to wrap an application daemon inside an SSL tunnel.

Prevention of breaches, like a trojan, are assisted by applications like GnuPG, specifically the ability to confirm signed packages, which recognizes modifications of the tarball after the packager creates it.

Finally, we touch on detection with a package that stores "signatures" of critical files (defined by the administrator) and then regenerates those "signatures" and compares for files that have been changed.

Vulnerabilities

About vulnerabilities

All software has bugs. Sometimes, a bug can be exploited, for example to allow users to gain enhanced privileges (perhaps gaining a root shell, or simply accessing or deleting other user's files), or to allow a remote site to crash an application (denial of service), or for theft of data. These bugs are labelled as vulnerabilities.

The main place where vulnerabilities get logged is cve.mitre.org. Unfortunately, many vulnerability numbers (CVE-yyyy-nnnn) are initially only labelled as "reserved" when distributions start issuing fixes. Also, some vulnerabilities apply to particular combinations of configure options, or only apply to old versions of packages which have long since been updated in BLFS.

BLFS differs from distributions—there is no BLFS security team, and the editors only become aware of vulnerabilities after they are public knowledge. Sometimes, a package with a vulnerability will not be updated in the book for a long time. Issues can be logged in the Trac system, which might speed up resolution.

The normal way for BLFS to fix a vulnerability is, ideally, to update the book to a new fixed release of the package. Sometimes that happens even before the vulnerability is public knowledge, so there is no guarantee that it will be shown as a vulnerability fix in the Changelog. Alternatively, a sed command, or a patch taken from a distribution, may be appropriate.

The bottom line is that you are responsible for your own security, and for assessing the potential impact of any problems.

The editors now issue Security Advisories for packages in BLFS (and LFS), which can be found at BLFS Security Advisories, and grade the severity according to what upstream reports, or to what is shown at nvd.nist.gov if that has details.

To keep track of what is being discovered, you may wish to follow the security announcements of one or more distributions. For example, Debian has Debian security. Fedora's links on security are at the Fedora wiki. Details of Gentoo linux security announcements are discussed at Gentoo security. Finally, the Slackware archives of security announcements are at Slackware security.

The most general English source is perhaps the Full Disclosure Mailing List, but please read the comment on that page. If you use other languages you may prefer other sites such as heise.de (German) or cert.hr (Croatian). These are not linux-specific. There is also a daily update at lwn.net for subscribers (free access to the data after 2 weeks, but their vulnerabilities database at lwn.net/Vulnerabilities is unrestricted).

For some packages, subscribing to their 'announce' lists will provide prompt news of newer versions.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/vulnerabilities

make-ca-1.10

Introduction to make-ca

Public Key Infrastructure (PKI) is a method to validate the authenticity of an otherwise unknown entity across untrusted networks. PKI works by establishing a chain of trust, rather than trusting each individual host or entity explicitly. In order for a certificate presented by a remote entity to be trusted, that certificate must present a complete chain of certificates that can be validated using the root certificate of a Certificate Authority (CA) that is trusted by the local machine.

Establishing trust with a CA involves validating things like company address, ownership, contact information, etc., and ensuring that the CA has followed best practices, such as undergoing periodic security audits by independent investigators and maintaining an always available certificate revocation list. This is well outside the scope of BLFS (as it is for most Linux distributions). The certificate store provided here is taken from the Mozilla Foundation, who have established very strict inclusion policies described here.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

make-ca Dependencies

Required

p11-kit-0.24.1 (required at runtime to generate certificate stores from trust anchors)

Optional (runtime)

nss-3.78 (to generate a shared NSSDB)

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/make-ca

Installation of make-ca

The make-ca script will download and process the certificates included in the certdata.txt file for use as trust anchors for the p11-kit-0.24.1 trust module. Additionally, it will generate system certificate stores used by BLFS applications (if the recommended and optional applications are present on the system). Any local certificates stored in /etc/ssl/local will be imported to both the trust anchors and the generated certificate stores (overriding Mozilla's trust). Additionally, any modified trust values will be copied from the trust anchors to /etc/ssl/local prior to any updates, preserving custom trust values that differ from Mozilla when using the trust utility from p11-kit to operate on the trust store.

To install the various certificate stores, first install the make-ca script into the correct location. As the root user:

make install &&
install -vdm755 /etc/ssl/local

As the root user, after installing p11-kit-0.24.1, download the certificate source and prepare for system use with the following command:

Note

If running the script a second time with the same version of certdata.txt, for instance, to update the stores when make-ca is upgraded, or to add additional stores as the requisite software is installed, replace the -g switch with the -r switch in the command line. If packaging, run make-ca --help to see all available command line options.

/usr/sbin/make-ca -g

You should periodically update the store with the above command, either manually, or via a cron job. If you've installed Fcron-3.2.1 and completed the section on periodic jobs, execute the following commands, as the root user, to create a weekly cron job:

cat > /etc/cron.weekly/update-pki.sh << "EOF" &&
#!/bin/bash
/usr/sbin/make-ca -g
EOF
chmod 754 /etc/cron.weekly/update-pki.sh

Configuring make-ca

For most users, no additional configuration is necessary, however, the default certdata.txt file provided by make-ca is obtained from the mozilla-release branch, and is modified to provide a Mercurial revision. This will be the correct version for most systems. There are several other variants of the file available for use that might be preferred for one reason or another, including the files shipped with Mozilla products in this book. RedHat and OpenSUSE, for instance, use the version included in nss-3.78. Additional upstream downloads are available at the links included in /etc/make-ca.conf.dist. Simply copy the file to /etc/make-ca.conf and edit as appropriate.

About Trust Arguments

There are three trust types that are recognized by the make-ca script, SSL/TLS, S/Mime, and code signing. For OpenSSL, these are serverAuth, emailProtection, and codeSigning respectively. If one of the three trust arguments is omitted, the certificate is neither trusted, nor rejected for that role. Clients that use OpenSSL or NSS encountering this certificate will present a warning to the user. Clients using GnuTLS without p11-kit support are not aware of trusted certificates. To include this CA into the ca-bundle.crt, email-ca-bundle.crt, or objsign-ca-bundle.crt files (the GnuTLS legacy bundles), it must have the appropriate trust arguments.

Adding Additional CA Certificates

The /etc/ssl/local directory is available to add additional CA certificates to the system trust store. This directory is also used to store certificates that were added to or modified in the system trust store by p11-kit-0.24.1 so that trust values are maintained across upgrades. Files in this directory must be in the OpenSSL trusted certificate format. Certificates imported using the trust utility from p11-kit-0.24.1 will utilize the x509 Extended Key Usage values to assign default trust values for the system anchors.

If you need to override trust values, or otherwise need to create an OpenSSL trusted certificate manually from a regular PEM encoded file, you need to add trust arguments to the openssl command, and create a new certificate. For example, using the CAcert roots, if you want to trust both for all three roles, the following commands will create appropriate OpenSSL trusted certificates (run as the root user after Wget-1.21.3 is installed):

wget http://www.cacert.org/certs/root.crt &&
wget http://www.cacert.org/certs/class3.crt &&
openssl x509 -in root.crt -text -fingerprint -setalias "CAcert Class 1 root" \
        -addtrust serverAuth -addtrust emailProtection -addtrust codeSigning \
        > /etc/ssl/local/CAcert_Class_1_root.pem &&
openssl x509 -in class3.crt -text -fingerprint -setalias "CAcert Class 3 root" \
        -addtrust serverAuth -addtrust emailProtection -addtrust codeSigning \
        > /etc/ssl/local/CAcert_Class_3_root.pem &&
/usr/sbin/make-ca -r

Overriding Mozilla Trust

Occasionally, there may be instances where you don't agree with Mozilla's inclusion of a particular certificate authority. If you'd like to override the default trust of a particular CA, simply create a copy of the existing certificate in /etc/ssl/local with different trust arguments. For example, if you'd like to distrust the "Makebelieve_CA_Root" file, run the following commands:

openssl x509 -in /etc/ssl/certs/Makebelieve_CA_Root.pem \
             -text \
             -fingerprint \
             -setalias "Disabled Makebelieve CA Root" \
             -addreject serverAuth \
             -addreject emailProtection \
             -addreject codeSigning \
       > /etc/ssl/local/Disabled_Makebelieve_CA_Root.pem &&
/usr/sbin/make-ca -r

Contents

Installed Programs: make-ca
Installed Directories: /etc/ssl/{certs,local} and /etc/pki/{nssdb,anchors,tls/{certs,java}}

Short Descriptions

make-ca

is a shell script that adapts a current version of certdata.txt, and prepares it for use as the system trust store

CrackLib-2.9.7

Introduction to CrackLib

The CrackLib package contains a library used to enforce strong passwords by comparing user selected passwords to words in chosen word lists.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Additional Downloads

There are additional word lists available for download, e.g., from http://www.cotse.com/tools/wordlists.htm. CrackLib can utilize as many, or as few word lists you choose to install.

Important

Users tend to base their passwords on regular words of the spoken language, and crackers know that. CrackLib is intended to filter out such bad passwords at the source using a dictionary created from word lists. To accomplish this, the word list(s) for use with CrackLib must be an exhaustive list of words and word-based keystroke combinations likely to be chosen by users of the system as (guessable) passwords.

The default word list recommended above for downloading mostly satisfies this role in English-speaking countries. In other situations, it may be necessary to download (or even create) additional word lists.

Note that word lists suitable for spell-checking are not usable as CrackLib word lists in countries with non-Latin based alphabets, because of word-based keystroke combinations that make bad passwords.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/cracklib

Installation of CrackLib

Install CrackLib by running the following commands:

sed -i '/skipping/d' util/packer.c &&

sed -i '15209 s/.*/am_cv_python_version=3.10/' configure &&

PYTHON=python3 CPPFLAGS=-I/usr/include/python3.10 \
./configure --prefix=/usr    \
            --disable-static \
            --with-default-dict=/usr/lib/cracklib/pw_dict &&
make

Now, as the root user:

make install

Issue the following commands as the root user to install the recommended word list and create the CrackLib dictionary. Other word lists (text based, one word per line) can also be used by simply installing them into /usr/share/dict and adding them to the create-cracklib-dict command.

install -v -m644 -D    ../cracklib-words-2.9.7.bz2 \
                         /usr/share/dict/cracklib-words.bz2    &&

bunzip2 -v               /usr/share/dict/cracklib-words.bz2    &&
ln -v -sf cracklib-words /usr/share/dict/words                 &&
echo $(hostname) >>      /usr/share/dict/cracklib-extra-words  &&
install -v -m755 -d      /usr/lib/cracklib                     &&

create-cracklib-dict     /usr/share/dict/cracklib-words \
                         /usr/share/dict/cracklib-extra-words

If desired, check the proper operation of the library as an unprivileged user by issuing the following command:

make test

Important

If you are installing CrackLib after your LFS system has been completed and you have the Shadow package installed, you must reinstall Shadow-4.11.1 if you wish to provide strong password support on your system. If you are now going to install the Linux-PAM-1.5.2 package, you may disregard this note as Shadow will be reinstalled after the Linux-PAM installation.

Command Explanations

sed -i '/skipping/d' util/packer.c: Remove a meaningless warning.

PYTHON=python3: This forces the installation of python bindings for Python 3, even if Python 2 is installed.

CPPFLAGS=-I/usr/include/python3.10: This works around an issue caused by incorrect usage of Python 3 headers.

--with-default-dict=/lib/cracklib/pw_dict: This parameter forces the installation of the CrackLib dictionary to the /lib hierarchy.

--disable-static: This switch prevents installation of static versions of the libraries.

install -v -m644 -D ...: This command creates the /usr/share/dict directory (if it doesn't already exist) and installs the compressed word list there.

ln -v -s cracklib-words /usr/share/dict/words: The word list is linked to /usr/share/dict/words as historically, words is the primary word list in the /usr/share/dict directory. Omit this command if you already have a /usr/share/dict/words file installed on your system.

echo $(hostname) >>...: The value of hostname is echoed to a file called cracklib-extra-words. This extra file is intended to be a site specific list which includes easy to guess passwords such as company or department names, user names, product names, computer names, domain names, etc.

create-cracklib-dict ...: This command creates the CrackLib dictionary from the word lists. Modify the command to add any additional word lists you have installed.

Contents

Installed Programs: cracklib-check, cracklib-format, cracklib-packer, cracklib-unpacker and create-cracklib-dict
Installed Libraries: libcrack.so and the _cracklib.so (Python module)
Installed Directories: /lib/cracklib, /usr/share/dict and /usr/share/cracklib

Short Descriptions

cracklib-check

is used to determine if a password is strong

cracklib-format

is used to format text files (lowercases all words, removes control characters and sorts the lists)

cracklib-packer

creates a database with words read from standard input

cracklib-unpacker

displays on standard output the database specified

create-cracklib-dict

is used to create the CrackLib dictionary from the given word list(s)

libcrack.so

provides a fast dictionary lookup method for strong password enforcement

cryptsetup-2.4.3

Introduction to cryptsetup

cryptsetup is used to set up transparent encryption of block devices using the kernel crypto API.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

cryptsetup Dependencies

Required

JSON-C-0.16, LVM2-2.03.15, and popt-1.18

Optional

libpwquality-1.4.4, argon2, libssh, and passwdqc

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/cryptsetup

Kernel Configuration

Encrypted block devices require kernel support. To use it, the appropriate kernel configuration parameters need to be set:

Device Drivers  --->
  [*] Multiple devices driver support (RAID and LVM) ---> [CONFIG_MD]
       <*/M> Device mapper support                        [CONFIG_BLK_DEV_DM]
       <*/M> Crypt target support                         [CONFIG_DM_CRYPT]

Cryptographic API  --->
  <*/M> XTS support                                       [CONFIG_CRYPTO_XTS]
  <*/M> SHA224 and SHA256 digest algorithm                [CONFIG_CRYPTO_SHA256]
  <*/M> AES cipher algorithms                             [CONFIG_CRYPTO_AES]
  <*/M> User-space interface for symmetric key cipher algorithms
                                                          [CONFIG_CRYPTO_USER_API_SKCIPHER]
  For tests:
  <*/M> Twofish cipher algorithm                          [CONFIG_CRYPTO_TWOFISH]

Installation of cryptsetup

Install cryptsetup by running the following commands:

./configure --prefix=/usr --disable-ssh-token &&
make

To test the result, issue as the root user: make check. Some tests will fail if appropriate kernel configuration options are not set. Some additional options that may be needed for tests are: CONFIG_SCSI_LOWLEVEL, CONFIG_SCSI_DEBUG, CONFIG_BLK_DEV_DM_BUILTIN, CONFIG_CRYPTO_USER, CONFIG_CRYPTO_CRYPTD, CONFIG_CRYPTO_LRW, CONFIG_CRYPTO_XTS, CONFIG_CRYPTO_ESSIV, CONFIG_CRYPTO_CRCT10DIF, CONFIG_CRYPTO_AES_TI, CONFIG_CRYPTO_AES_NI_INTEL, CONFIG_CRYPTO_BLOWFISH, CONFIG_CRYPTO_CAST5, CONFIG_CRYPTO_SERPENT, CONFIG_CRYPTO_SERPENT_SSE2_X86_64, CONFIG_CRYPTO_SERPENT_AVX_X86_64, CONFIG_CRYPTO_SERPENT_AVX2_X86_64, and CONFIG_CRYPTO_TWOFISH_X86_64.

Now, as the root user:

make install

Command Explanations

--disable-ssh-token: This option is required if the optional libssh dependency is not installed.

Configuring cryptsetup

Because of the number of possible configurations, setup of encrypted volumes is beyond the scope of the BLFS book. Please see the configuration guide in the cryptsetup FAQ.

Contents

Installed Programs: cryptsetup, cryptsetup-reencrypt, integritysetup, and veritysetup
Installed Libraries: libcryptsetup.so
Installed Directories: None

Short Descriptions

cryptsetup

is used to setup dm-crypt managed device-mapper mappings

cryptsetup-reencrypt

is a tool for offline LUKS device re-encryption

integritysetup

is a tool to manage dm-integrity (block level integrity) volumes

veritysetup

is used to configure dm-verity managed device-mapper mappings. Device-mapper verity target provides read-only transparent integrity checking of block devices using kernel crypto API

Cyrus SASL-2.1.28

Introduction to Cyrus SASL

The Cyrus SASL package contains a Simple Authentication and Security Layer implementation, a method for adding authentication support to connection-based protocols. To use SASL, a protocol includes a command for identifying and authenticating a user to a server and for optionally negotiating protection of subsequent protocol interactions. If its use is negotiated, a security layer is inserted between the protocol and the connection.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Cyrus SASL Dependencies

Recommended
Optional

Linux-PAM-1.5.2, MIT Kerberos V5-1.19.3, MariaDB-10.6.7 or MySQL, OpenJDK-18.0.1, OpenLDAP-2.6.2, PostgreSQL-14.2, SQLite-3.38.4, krb4, Dmalloc, Pod::POM::View::Restructured, and Sphinx

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/cyrus-sasl

Installation of Cyrus SASL

Note

This package does not support parallel build.

Install Cyrus SASL by running the following commands:

./configure --prefix=/usr        \
            --sysconfdir=/etc    \
            --enable-auth-sasldb \
            --with-dbpath=/var/lib/sasl/sasldb2 \
            --with-sphinx-build=no              \
            --with-saslauthd=/var/run/saslauthd &&
make -j1

This package does not come with a test suite. If you are planning on using the GSSAPI authentication mechanism, test it after installing the package using the sample server and client programs which were built in the preceding step. Instructions for performing the tests can be found at https://www.linuxfromscratch.org/hints/downloads/files/cyrus-sasl.txt.

Now, as the root user:

make install &&
install -v -dm755                          /usr/share/doc/cyrus-sasl-2.1.28/html &&
install -v -m644  saslauthd/LDAP_SASLAUTHD /usr/share/doc/cyrus-sasl-2.1.28      &&
install -v -m644  doc/legacy/*.html        /usr/share/doc/cyrus-sasl-2.1.28/html &&
install -v -dm700 /var/lib/sasl

Command Explanations

--with-dbpath=/var/lib/sasl/sasldb2: This switch forces the sasldb database to be created in /var/lib/sasl instead of /etc.

--with-saslauthd=/var/run/saslauthd: This switch forces saslauthd to use the FHS compliant directory /var/run/saslauthd for variable run-time data.

--enable-auth-sasldb: This switch enables SASLDB authentication backend.

--with-dblib=gdbm: This switch forces GDBM to be used instead of Berkeley DB.

--with-ldap: This switch enables the OpenLDAP support.

--enable-ldapdb: This switch enables the LDAPDB authentication backend.

--enable-java: This switch enables compiling of the Java support libraries.

--enable-login: This option enables unsupported LOGIN authentication.

--enable-ntlm: This option enables unsupported NTLM authentication.

install -v -m644 ...: These commands install documentation which is not installed by the make install command.

install -v -m700 -d /var/lib/sasl: This directory must exist when starting saslauthd or using the sasldb plugin. If you're not going to be running the daemon or using the plugins, you may omit the creation of this directory.

Configuring Cyrus SASL

Config Files

/etc/saslauthd.conf (for saslauthd LDAP configuration) and /etc/sasl2/Appname.conf (where "Appname" is the application defined name of the application)

Configuration Information

See https://www.cyrusimap.org/sasl/sasl/sysadmin.html for information on what to include in the application configuration files.

See file:///usr/share/doc/cyrus-sasl-2.1.28/LDAP_SASLAUTHD for configuring saslauthd with OpenLDAP.

See https://www.cyrusimap.org/sasl/sasl/gssapi.html#gssapi for configuring saslauthd with Kerberos.

Init Script

If you need to run the saslauthd daemon at system startup, install the /etc/rc.d/init.d/saslauthd init script included in the blfs-bootscripts-20210826 package using the following command:

make install-saslauthd

Note

You'll need to modify /etc/sysconfig/saslauthd and modify the AUTHMECH parameter with your desired authentication mechanism.

Contents

Installed Programs: pluginviewer, saslauthd, sasldblistusers2, saslpasswd2 and testsaslauthd
Installed Library: libsasl2.so
Installed Directories: /usr/include/sasl, /usr/lib/sasl2, /usr/share/doc/cyrus-sasl-2.1.28 and /var/lib/sasl

Short Descriptions

pluginviewer

is used to list loadable SASL plugins and their properties

saslauthd

is the SASL authentication server

sasldblistusers2

is used to list the users in the SASL password database sasldb2

saslpasswd2

is used to set and delete a user's SASL password and mechanism specific secrets in the SASL password database sasldb2

testsaslauthd

is a test utility for the SASL authentication server

libsasl2.so

is a general purpose authentication library for server and client applications

GnuPG-2.3.6

Introduction to GnuPG

The GnuPG package is GNU's tool for secure communication and data storage. It can be used to encrypt data and to create digital signatures. It includes an advanced key management facility and is compliant with the proposed OpenPGP Internet standard as described in RFC2440 and the S/MIME standard as described by several RFCs. GnuPG 2 is the stable version of GnuPG integrating support for OpenPGP and S/MIME.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

GnuPG 2 Dependencies

Required

libassuan-2.5.5, libgcrypt-1.10.1, libksba-1.6.0, and npth-1.6

Recommended
Optional

cURL-7.83.0, Fuse-3.10.5, ImageMagick-7.1.0-25 (for the convert utility, used for generating the documentation), libusb-1.0.26, an MTA, OpenLDAP-2.6.2, SQLite-3.38.4, texlive-20220321 (or install-tl-unx), fig2dev (for generating documentation), and GNU adns

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/gnupg2

Installation of GnuPG

Install GnuPG by running the following commands:

./configure --prefix=/usr            \
            --localstatedir=/var     \
            --sysconfdir=/etc        \
            --docdir=/usr/share/doc/gnupg-2.3.6 &&
make &&

makeinfo --html --no-split -o doc/gnupg_nochunks.html doc/gnupg.texi &&
makeinfo --plaintext       -o doc/gnupg.txt           doc/gnupg.texi &&
make -C doc html

If you have texlive-20220321 installed and you wish to create documentation in alternate formats, issue the following commands (fig2dev is needed for the ps format):

make -C doc pdf ps

To test the results, issue: make check.

Now, as the root user:

make install &&

install -v -m755 -d /usr/share/doc/gnupg-2.3.6/html            &&
install -v -m644    doc/gnupg_nochunks.html \
                    /usr/share/doc/gnupg-2.3.6/html/gnupg.html &&
install -v -m644    doc/*.texi doc/gnupg.txt \
                    /usr/share/doc/gnupg-2.3.6 &&
install -v -m644    doc/gnupg.html/* \
                    /usr/share/doc/gnupg-2.3.6/html

If you created alternate formats of the documentation, install them using the following command as the root user:

install -v -m644 doc/gnupg.{pdf,dvi,ps} \
                 /usr/share/doc/gnupg-2.3.6

Command Explanations

--docdir=/usr/share/doc/gnupg-2.3.6: This switch changes the default docdir to /usr/share/doc/gnupg-2.3.6.

--enable-all-tests: This switch allows more tests to be run with make check.

--enable-g13: This switch enables building the g13 program.

Contents

Installed Programs: addgnupghome, applygnupgdefaults, dirmngr, dirmngr-client, g13 (optional), gpg-agent, gpg-connect-agent, gpg, gpgconf, gpgparsemail, gpgscm, gpgsm, gpgsplit, gpgtar, gpgv, gpg-wks-server, kbxutil, and watchgnupg
Installed Libraries: None
Installed Directories: /usr/share/doc/gnupg-2.3.6 and /usr/share/gnupg

Short Descriptions

addgnupghome

is used to create and populate a user's ~/.gnupg directories

applygnupgdefaults

is a wrapper script used to run gpgconf with the --apply-defaults parameter on all user's GnuPG home directories

dirmngr

is a tool that takes care of accessing the OpenPGP keyservers

dirmngr-client

is a tool to contact a running dirmngr and test whether a certificate has been revoked

g13

is a tool to create, mount or unmount an encrypted file system container (optional)

gpg-agent

is a daemon used to manage secret (private) keys independently from any protocol. It is used as a backend for gpg and gpgsm as well as for a couple of other utilities

gpg-connect-agent

is a utility used to communicate with a running gpg-agent

gpg

is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool used to provide digital encryption and signing services using the OpenPGP standard

gpgconf

is a utility used to automatically and reasonably safely query and modify configuration files in the ~/.gnupg home directory. It is designed not to be invoked manually by the user, but automatically by graphical user interfaces

gpgparsemail

is a utility currently only useful for debugging. Run it with --help for usage information

gpgscm

executes the given scheme program or spawns an interactive shell

gpgsm

is a tool similar to gpg used to provide digital encryption and signing services on X.509 certificates and the CMS protocol. It is mainly used as a backend for S/MIME mail processing

gpgsplit

splits an OpenPGP message into packets

gpgtar

is a tool to encrypt or sign files into an archive

gpgv

is a verify only version of gpg

gpg-wks-server

provides a server for the Web Key Service protocol

kbxutil

is used to list, export and import Keybox data

watchgnupg

is used to listen to a Unix Domain socket created by any of the GnuPG tools

GnuTLS-3.7.4

Introduction to GnuTLS

The GnuTLS package contains libraries and userspace tools which provide a secure layer over a reliable transport layer. Currently the GnuTLS library implements the proposed standards by the IETF's TLS working group. Quoting from the TLS protocol specification:

The TLS protocol provides communications privacy over the Internet. The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery.

GnuTLS provides support for TLS 1.3, TLS 1.2, TLS 1.1, TLS 1.0, and SSL 3.0 protocols, TLS extensions, including server name and max record size. Additionally, the library supports authentication using the SRP protocol, X.509 certificates and OpenPGP keys, along with support for the TLS Pre-Shared-Keys (PSK) extension, the Inner Application (TLS/IA) extension and X.509 and OpenPGP certificate handling.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

GnuTLS Dependencies

Required

Nettle-3.7.3

Recommended
Optional

Doxygen-1.9.3, GTK-Doc-1.33.2, Guile-3.0.8, libidn-1.38 or libidn2-2.3.2, libseccomp-2.5.4, Net-tools-2.10 (used during the test suite), texlive-20220321 or install-tl-unx, Unbound-1.15.0 (to build the DANE library), Valgrind-3.19.0 (used during the test suite), autogen, cmocka and datefudge (used during the test suite if the DANE library is built), and Trousers (Trusted Platform Module support)

Note

Note that if you do not install libtasn1-4.18.0, an older version shipped in the GnuTLS tarball will be used instead.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/gnutls

Installation of GnuTLS

Install GnuTLS by running the following commands:

./configure --prefix=/usr \
            --docdir=/usr/share/doc/gnutls-3.7.4 \
            --disable-guile \
            --disable-rpath \
            --with-default-trust-store-pkcs11="pkcs11:" &&
make

To test the results, issue: make check.

Now, as the root user:

make install

Command Explanations

--with-default-trust-store-pkcs11="pkcs11:": This switch tells gnutls to use the PKCS #11 trust store as the default trust. Omit this switch if p11-kit-0.24.1 is not installed.

--disable-guile: This switch disables GUILE support, since GnuTLS does not support Guile-2.2.x yet.

--disable-rpath: This switch prevents building GnuTLS utilities and tests with hardcoded runtime library search path. Hardcoded rpath is unneeded for BLFS, and it causes test failures if an old version of GnuTLS is installed.

--with-default-trust-store-file=/etc/pki/tls/certs/ca-bundle.crt: This switch tells configure where to find the legacy CA certificate bundle and to use it instead of PKCS #11 module by default. Use this if p11-kit-0.24.1 is not installed.

--enable-gtk-doc: Use this parameter if GTK-Doc is installed and you wish to rebuild and install the API documentation.

--enable-openssl-compatibility: Use this switch if you wish to build the OpenSSL compatibility library.

--without-p11-kit: use this switch if you have not installed p11-kit.

--with-included-unistring: uses the bundled version of libunistring, instead of the system one. Use this switch if you have not installed libunistring-1.0.

Contents

Installed Programs: certtool, danetool, gnutls-cli, gnutls-cli-debug, gnutls-serv, ocsptool, p11tool, psktool, and srptool
Installed Libraries: libgnutls.so, libgnutls-dane.so, libgnutlsxx.so, and libgnutls-openssl.so (optional)
Installed Directories: /usr/include/gnutls, /usr/share/gtk-doc/html/gnutls, and /usr/share/doc/gnutls-3.7.4

Short Descriptions

certtool

is used to generate X.509 certificates, certificate requests, and private keys

danetool

is a tool used to generate and check DNS resource records for the DANE protocol

gnutls-cli

is a simple client program to set up a TLS connection to some other computer

gnutls-cli-debug

is a simple client program to set up a TLS connection to some other computer and produces very verbose progress results

gnutls-serv

is a simple server program that listens to incoming TLS connections

ocsptool

is a program that can parse and print information about OCSP requests/responses, generate requests and verify responses

p11tool

is a program that allows handling data from PKCS #11 smart cards and security modules

psktool

is a simple program that generates random keys for use with TLS-PSK

srptool

is a simple program that emulates the programs in the Stanford SRP (Secure Remote Password) libraries using GnuTLS

libgnutls.so

contains the core API functions and X.509 certificate API functions

GPGME-1.17.1

Introduction to GPGME

The GPGME package is a C library that allows cryptography support to be added to a program. It is designed to make access to public key crypto engines like GnuPG or GpgSM easier for applications. GPGME provides a high-level crypto API for encryption, decryption, signing, signature verification and key management.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

GPGME Dependencies

Required

libassuan-2.5.5

Optional

Doxygen-1.9.3 and Graphviz-3.0.0 (for API documentation), GnuPG-2.3.6 (required if Qt or SWIG are installed; used during the testsuite), Clisp-2.49, Qt-5.15.2, and/or SWIG-4.0.2 (for language bindings)

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/gpgme

Installation of GPGME

First, fix an issue building the package with Glibc-2.34 or later:

sed 's/defined(__sun.*$/1/' -i src/posix-io.c

Next, fix an issue building with Python 3.10 installed:

sed -e 's/3\.9/3.10/'                    \
    -e 's/:3/:4/'                        \
    -e '23653 s/distutils"/setuptools"/' \
    -i configure

Install GPGME by running the following commands:

./configure --prefix=/usr --disable-gpg-test &&
make

To test the results, you should have GnuPG-2.3.6 installed and remove the --disable-gpg-test above. Issue: make -k check.

Now, as the root user:

make install

Command Explanations

--disable-gpg-test: if this parameter is not passed to configure, the test programs are built during make stage, which requires GnuPG-2.3.6. This parameter is not needed if GnuPG-2.3.6 is installed.

Contents

Installed Program: gpgme-config, gpgme-json, and gpgme-tool
Installed Libraries: libgpgme, libgpgmepp.so, and libqgpgme.so
Installed Directory: /usr/include/{gpgme++,qgpgme,QGpgME}, /usr/lib/cmake/{Gpgmepp,QGpgme}. /usr/lib/python{2.7,3.9}/site-packages/gpg, and /usr/share/common-lisp/source/gpgme

Short Descriptions

gpgme-config

is used to obtain GPGME compilation and linking information

gpgme-json

outputs GPGME commands in JSON format

gpgme-tool

is an assuan server exposing GPGME operations, such as printing fingerprints and keyids with keyservers

libgpgme.so

contains the GPGME API functions

libgpgmepp.so

contains the C++ GPGME API functions

libqgpgme.so

contains API functions for handling GPG operations in Qt applications

iptables-1.8.7

Introduction to iptables

iptables is a userspace command line program used to configure the Linux 2.4 and later kernel packet filtering ruleset.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

iptables Dependencies

Optional

libpcap-1.10.1 (required for nfsypproxy support), bpf-utils (required for Berkeley Packet Filter support), libnfnetlink (required for connlabel support), libnetfilter_conntrack (required for connlabel support), and nftables

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/iptables

Kernel Configuration

A firewall in Linux is accomplished through the netfilter interface. To use iptables to configure netfilter, the following kernel configuration parameters are required:

[*] Networking support  --->                                          [CONFIG_NET]
      Networking Options  --->
        [*] Network packet filtering framework (Netfilter) --->       [CONFIG_NETFILTER]
          [*] Advanced netfilter configuration                        [CONFIG_NETFILTER_ADVANCED]
          Core Netfilter Configuration --->
            <*/M> Netfilter connection tracking support               [CONFIG_NF_CONNTRACK]
            <*/M> Netfilter Xtables support (required for ip_tables)  [CONFIG_NETFILTER_XTABLES]
            <*/M> LOG target support                                  [CONFIG_NETFILTER_XT_TARGET_LOG]
          IP: Netfilter Configuration --->
            <*/M> IP tables support (required for filtering/masq/NAT) [CONFIG_IP_NF_IPTABLES]

Include any connection tracking protocols that will be used, as well as any protocols that you wish to use for match support under the "Core Netfilter Configuration" section. The above options are enough for running Creating a Personal Firewall With iptables below.

Installation of iptables

Note

The installation below does not include building some specialized extension libraries which require the raw headers in the Linux source code. If you wish to build the additional extensions (if you aren't sure, then you probably don't), you can look at the INSTALL file to see an example of how to change the KERNEL_DIR= parameter to point at the Linux source code. Note that if you upgrade the kernel version, you may also need to recompile iptables and that the BLFS team has not tested using the raw kernel headers.

Install iptables by running the following commands:

./configure --prefix=/usr      \
            --disable-nftables \
            --enable-libipq    &&
make

This package does not come with a test suite.

Now, as the root user:

make install

Command Explanations

--disable-nftables: This switch disables building nftables compatibility.

--enable-libipq: This switch enables building of libipq.so which can be used by some packages outside of BLFS.

--enable-nfsynproxy: This switch enables installation of nfsynproxy SYNPROXY configuration tool.

Configuring iptables

Note

In the following example configurations, LAN1 is used for the internal LAN interface, and WAN1 is used for the external interface connected to the Internet. You will need to replace these values with appropriate interface names for your system.

Personal Firewall

A Personal Firewall is designed to let you access all the services offered on the Internet while keeping your computer secure and your data private.

Below is a slightly modified version of Rusty Russell's recommendation from the Linux 2.4 Packet Filtering HOWTO. It is still applicable to the Linux 5.x kernels.

cat > /etc/rc.d/rc.iptables << "EOF"
#!/bin/sh

# Begin rc.iptables

# Insert connection-tracking modules
# (not needed if built into the kernel)
modprobe nf_conntrack
modprobe xt_LOG

# Enable broadcast echo Protection
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

# Disable Source Routed Packets
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route
echo 0 > /proc/sys/net/ipv4/conf/default/accept_source_route

# Enable TCP SYN Cookie Protection
echo 1 > /proc/sys/net/ipv4/tcp_syncookies

# Disable ICMP Redirect Acceptance
echo 0 > /proc/sys/net/ipv4/conf/default/accept_redirects

# Do not send Redirect Messages
echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects
echo 0 > /proc/sys/net/ipv4/conf/default/send_redirects

# Drop Spoofed Packets coming in on an interface, where responses
# would result in the reply going out a different interface.
echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
echo 1 > /proc/sys/net/ipv4/conf/default/rp_filter

# Log packets with impossible addresses.
echo 1 > /proc/sys/net/ipv4/conf/all/log_martians
echo 1 > /proc/sys/net/ipv4/conf/default/log_martians

# be verbose on dynamic ip-addresses  (not needed in case of static IP)
echo 2 > /proc/sys/net/ipv4/ip_dynaddr

# disable Explicit Congestion Notification
# too many routers are still ignorant
echo 0 > /proc/sys/net/ipv4/tcp_ecn

# Set a known state
iptables -P INPUT   DROP
iptables -P FORWARD DROP
iptables -P OUTPUT  DROP

# These lines are here in case rules are already in place and the
# script is ever rerun on the fly. We want to remove all rules and
# pre-existing user defined chains before we implement new rules.
iptables -F
iptables -X
iptables -Z

iptables -t nat -F

# Allow local-only connections
iptables -A INPUT  -i lo -j ACCEPT

# Free output on any interface to any ip for any service
# (equal to -P ACCEPT)
iptables -A OUTPUT -j ACCEPT

# Permit answers on already established connections
# and permit new connections related to established ones
# (e.g. port mode ftp)
iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT

# Log everything else.
iptables -A INPUT -j LOG --log-prefix "FIREWALL:INPUT "

# End $rc_base/rc.iptables
EOF
chmod 700 /etc/rc.d/rc.iptables

This script is quite simple, it drops all traffic coming into your computer that wasn't initiated from your computer, but as long as you are simply surfing the Internet you are unlikely to exceed its limits.

If you frequently encounter certain delays at accessing FTP servers, take a look at BusyBox with iptables example number 4.

Even if you have daemons or services running on your system, these will be inaccessible everywhere but from your computer itself. If you want to allow access to services on your machine, such as ssh or ping, take a look at Creating a BusyBox With iptables.

Masquerading Router

A Network Firewall has two interfaces, one connected to an intranet, in this example LAN1, and one connected to the Internet, here WAN1. To provide the maximum security for the firewall itself, make sure that there are no unnecessary servers running on it such as X11. As a general principle, the firewall itself should not access any untrusted service (think of a remote server giving answers that makes a daemon on your system crash, or even worse, that implements a worm via a buffer-overflow).

cat > /etc/rc.d/rc.iptables << "EOF"
#!/bin/sh

# Begin rc.iptables

echo
echo "You're using the example configuration for a setup of a firewall"
echo "from Beyond Linux From Scratch."
echo "This example is far from being complete, it is only meant"
echo "to be a reference."
echo "Firewall security is a complex issue, that exceeds the scope"
echo "of the configuration rules below."
echo "You can find additional information"
echo "about firewalls in Chapter 4 of the BLFS book."
echo "https://www.linuxfromscratch.org/blfs"
echo

# Insert iptables modules (not needed if built into the kernel).

modprobe nf_conntrack
modprobe nf_conntrack_ftp
modprobe xt_conntrack
modprobe xt_LOG
modprobe xt_state

# Enable broadcast echo Protection
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

# Disable Source Routed Packets
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route

# Enable TCP SYN Cookie Protection
echo 1 > /proc/sys/net/ipv4/tcp_syncookies

# Disable ICMP Redirect Acceptance
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects

# Don't send Redirect Messages
echo 0 > /proc/sys/net/ipv4/conf/default/send_redirects

# Drop Spoofed Packets coming in on an interface where responses
# would result in the reply going out a different interface.
echo 1 > /proc/sys/net/ipv4/conf/default/rp_filter

# Log packets with impossible addresses.
echo 1 > /proc/sys/net/ipv4/conf/all/log_martians

# Be verbose on dynamic ip-addresses  (not needed in case of static IP)
echo 2 > /proc/sys/net/ipv4/ip_dynaddr

# Disable Explicit Congestion Notification
# Too many routers are still ignorant
echo 0 > /proc/sys/net/ipv4/tcp_ecn

# Set a known state
iptables -P INPUT   DROP
iptables -P FORWARD DROP
iptables -P OUTPUT  DROP

# These lines are here in case rules are already in place and the
# script is ever rerun on the fly. We want to remove all rules and
# pre-existing user defined chains before we implement new rules.
iptables -F
iptables -X
iptables -Z

iptables -t nat -F

# Allow local connections
iptables -A INPUT  -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

# Allow forwarding if the initiated on the intranet
iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD ! -i WAN1 -m conntrack --ctstate NEW       -j ACCEPT

# Do masquerading
# (not needed if intranet is not using private ip-addresses)
iptables -t nat -A POSTROUTING -o WAN1 -j MASQUERADE

# Log everything for debugging
# (last of all rules, but before policy rules)
iptables -A INPUT   -j LOG --log-prefix "FIREWALL:INPUT "
iptables -A FORWARD -j LOG --log-prefix "FIREWALL:FORWARD "
iptables -A OUTPUT  -j LOG --log-prefix "FIREWALL:OUTPUT "

# Enable IP Forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward
EOF
chmod 700 /etc/rc.d/rc.iptables

With this script your intranet should be reasonably secure against external attacks. No one should be able to setup a new connection to any internal service and, if it's masqueraded, makes your intranet invisible to the Internet. Furthermore, your firewall should be relatively safe because there are no services running that a cracker could attack.

BusyBox

This scenario isn't too different from the Creating a Masquerading Router With iptables, but additionally offers some services to your intranet. Examples of this can be when you want to administer your firewall from another host on your intranet or use it as a proxy or a name server.

Note

Outlining specifically how to protect a server that offers services on the Internet goes far beyond the scope of this document. See the references in the section called “Extra Information” for more information.

Be cautious. Every service you have enabled makes your setup more complex and your firewall less secure. You are exposed to the risks of misconfigured services or running a service with an exploitable bug. A firewall should generally not run any extra services. See the introduction to the Creating a Masquerading Router With iptables for some more details.

If you want to add services such as internal Samba or name servers that do not need to access the Internet themselves, the additional statements are quite simple and should still be acceptable from a security standpoint. Just add the following lines into the script before the logging rules.

iptables -A INPUT  -i ! WAN1  -j ACCEPT
iptables -A OUTPUT -o ! WAN1  -j ACCEPT

If daemons, such as squid, have to access the Internet themselves, you could open OUTPUT generally and restrict INPUT.

iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -j ACCEPT

However, it is generally not advisable to leave OUTPUT unrestricted. You lose any control over trojans who would like to "call home", and a bit of redundancy in case you've (mis-)configured a service so that it broadcasts its existence to the world.

To accomplish this, you should restrict INPUT and OUTPUT on all ports except those that it's absolutely necessary to have open. Which ports you have to open depends on your needs: mostly you will find them by looking for failed accesses in your log files.

Have a Look at the Following Examples:

  • Squid is caching the web:

    iptables -A OUTPUT -p tcp --dport 80 -j ACCEPT
    iptables -A INPUT  -p tcp --sport 80 -m conntrack --ctstate ESTABLISHED \
      -j ACCEPT
  • Your caching name server (e.g., named) does its lookups via UDP:

    iptables -A OUTPUT -p udp --dport 53 -j ACCEPT
  • You want to be able to ping your computer to ensure it's still alive:

    iptables -A INPUT  -p icmp -m icmp --icmp-type echo-request -j ACCEPT
    iptables -A OUTPUT -p icmp -m icmp --icmp-type echo-reply   -j ACCEPT
  • If you are frequently accessing FTP servers or enjoy chatting, you might notice delays because some implementations of these daemons query an identd daemon on your system to obtain usernames. Although there's really little harm in this, having an identd running is not recommended because many security experts feel the service gives out too much additional information.

    To avoid these delays you could reject the requests with a 'tcp-reset' response:

    iptables -A INPUT  -p tcp --dport 113 -j REJECT --reject-with tcp-reset
  • To log and drop invalid packets (packets that came in after netfilter's timeout or some types of network scans) insert these rules at the top of the chain:

    iptables -I INPUT 0 -p tcp -m conntrack --ctstate INVALID \
      -j LOG --log-prefix "FIREWALL:INVALID "
    iptables -I INPUT 1 -p tcp -m conntrack --ctstate INVALID -j DROP
  • Anything coming from the outside should not have a private address, this is a common attack called IP-spoofing:

    iptables -A INPUT -i WAN1 -s 10.0.0.0/8     -j DROP
    iptables -A INPUT -i WAN1 -s 172.16.0.0/12  -j DROP
    iptables -A INPUT -i WAN1 -s 192.168.0.0/16 -j DROP

    There are other addresses that you may also want to drop: 0.0.0.0/8, 127.0.0.0/8, 224.0.0.0/3 (multicast and experimental), 169.254.0.0/16 (Link Local Networks), and 192.0.2.0/24 (IANA defined test network).

  • If your firewall is a DHCP client, you need to allow those packets:

    iptables -A INPUT  -i WAN1 -p udp -s 0.0.0.0 --sport 67 \
       -d 255.255.255.255 --dport 68 -j ACCEPT
  • To simplify debugging and be fair to anyone who'd like to access a service you have disabled, purposely or by mistake, you could REJECT those packets that are dropped.

    Obviously this must be done directly after logging as the very last lines before the packets are dropped by policy:

    iptables -A INPUT -j REJECT

These are only examples to show you some of the capabilities of the firewall code in Linux. Have a look at the man page of iptables. There you will find much more information. The port numbers needed for this can be found in /etc/services, in case you didn't find them by trial and error in your log file.

Boot Script

To set up the iptables firewall at boot, install the /etc/rc.d/init.d/iptables init script included in the blfs-bootscripts-20210826 package.

make install-iptables

Contents

Installed Programs: ip6tables, ip6tables-apply, ip6tables-legacy, ip6tables-legacy-restore, ip6tables-legacy-save, ip6tables-restore, ip6tables-save, iptables, iptables-apply, iptables-legacy, iptables-legacy-restore, iptables-legacy-apply, iptables-restore, iptables-save, iptables-xml, nfsynproxy (optional), and xtables-multi
Installed Libraries: libip4tc.so, libip6tc.so, libipq.so, libiptc.so, and libxtables.so
Installed Directories: /lib/xtables and /usr/include/libiptc

Short Descriptions

iptables

is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel

iptables-apply

is a safer way to update iptables remotely

iptables-legacy

is used to interact with iptables using the legacy command set

iptables-legacy-restore

is used to restore a set of legacy iptables rules

iptables-legacy-save

is used to save a set of legacy iptables rules

iptables-restore

is used to restore IP Tables from data specified on STDIN. Use I/O redirection provided by your shell to read from a file

iptables-save

is used to dump the contents of an IP Table in easily parseable format to STDOUT. Use I/O-redirection provided by your shell to write to a file

iptables-xml

is used to convert the output of iptables-save to an XML format. Using the iptables.xslt stylesheet converts the XML back to the format of iptables-restore

ip6tables*

are a set of commands for IPV6 that parallel the iptables commands above

nfsynproxy

(optional) configuration tool. SYNPROXY target makes handling of large SYN floods possible without the large performance penalties imposed by the connection tracking in such cases

xtables-multi

is a binary that behaves according to the name it is called by

Setting Up a Network Firewall

Introduction to Firewall Creation

The purpose of a firewall is to protect a computer or a network against malicious access. In a perfect world every daemon or service, on every machine, is perfectly configured and immune to security flaws, and all users are trusted implicitly to use the equipment as intended. However, this is rarely, if ever, the case. Daemons may be misconfigured, or updates may not have been applied for known exploits against essential services. Additionally, you may wish to choose which services are accessible by certain machines or users, or you may wish to limit which machines or applications are allowed external access. Alternatively, you simply may not trust some of your applications or users. For these reasons, a carefully designed firewall should be an essential part of system security.

While a firewall can greatly limit the scope of the above issues, do not assume that having a firewall makes careful configuration redundant, or that any negligent misconfiguration is harmless. A firewall does not prevent the exploitation of any service you offer outside of it. Despite having a firewall, you need to keep applications and daemons properly configured and up to date.

Meaning of the Word "Firewall"

The word firewall can have several different meanings.

Personal Firewall

This is a hardware device or software program, intended to secure a home or desktop computer connected to the Internet. This type of firewall is highly relevant for users who do not know how their computers might be accessed via the Internet or how to disable that access, especially if they are always online and connected via broadband links.

An example configuration for a personal firewall is provided at Creating a Personal Firewall With iptables.

Masquerading Router

This is a system placed between the Internet and an intranet. To minimize the risk of compromising the firewall itself, it should generally have only one role—that of protecting the intranet. Although not completely risk-free, the tasks of doing the routing and IP masquerading (rewriting IP headers of the packets it routes from clients with private IP addresses onto the Internet so that they seem to come from the firewall itself) are commonly considered relatively secure.

An example configuration for a masquerading firewall is provided at Creating a Masquerading Router With iptables.

BusyBox

This is often an old computer you may have retired and nearly forgotten, performing masquerading or routing functions, but offering non-firewall services such as a web-cache or mail. This may be used for home networks, but is not to be considered as secure as a firewall only machine because the combination of server and router/firewall on one machine raises the complexity of the setup.

An example configuration for a BusyBox is provided at Creating a BusyBox With iptables.

Firewall with a Demilitarized Zone

This type of firewall performs masquerading or routing, but grants public access to some branch of your network that is physically separated from your regular intranet and is essentially a separate network with direct Internet access. The servers on this network are those which must be easily accessible from both the Internet and intranet. The firewall protects both networks. This type of firewall has a minimum of three network interfaces.

Packetfilter

This type of firewall does routing or masquerading but does not maintain a state table of ongoing communication streams. It is fast but quite limited in its ability to block undesired packets without blocking desired packets.

Conclusion

Caution

The example configurations provided for iptables-1.8.7 are not intended to be a complete guide to securing systems. Firewalling is a complex issue that requires careful configuration. The configurations provided by BLFS are intended only to give examples of how a firewall works. They are not intended to fit any particular configuration and may not provide complete protection from an attack.

BLFS provides an utility to manage the kernel Netfilter interface, iptables-1.8.7. It has been around since early 2.4 kernels, and has been the standard since. This is likely the set of tools that will be most familiar to existing admins. Other tools have been developed more recently, see the list of further readings below for more details. Here you will find a list of URLs that contain comprehensive information about building firewalls and further securing your system.

libcap-2.64 with PAM

Introduction to libcap with PAM

The libcap package was installed in LFS, but if Linux-PAM support is desired, the PAM module must be built (after installation of Linux-PAM).

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

libcap Dependencies

Required

Linux-PAM-1.5.2

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/libcap

Installation of libcap

Note

If you are upgrading libcap from a previous version, use the instructions in LFS libcap page to upgrade libcap. If Linux-PAM-1.5.2 has been built, the PAM module will automatically be built too.

Install libcap by running the following commands:

make -C pam_cap

This package does not come with a test suite.

Now, as the root user:

install -v -m755 pam_cap/pam_cap.so /usr/lib/security &&
install -v -m644 pam_cap/capability.conf /etc/security

Configuring Libcap

In order to allow Linux-PAM to grant privileges based on POSIX capabilities, you need to add the libcap module to the beginning of the /etc/pam.d/system-auth file. Make the required edits with the following commands:

mv -v /etc/pam.d/system-auth{,.bak} &&
cat > /etc/pam.d/system-auth << "EOF" &&
# Begin /etc/pam.d/system-auth

auth      optional    pam_cap.so
EOF
tail -n +3 /etc/pam.d/system-auth.bak >> /etc/pam.d/system-auth

Additionally, you'll need to modify the /etc/security/capability.conf file to grant necessary privileges to users, and utilize the setcap utility to set capabilities on specific utilities as needed. See man 8 setcap and man 3 cap_from_text for additional information.

Contents

Installed Programs: None
Installed Library: pam_cap.so
Installed Directories: None

Linux-PAM-1.5.2

Introduction to Linux PAM

The Linux PAM package contains Pluggable Authentication Modules used to enable the local system administrator to choose how applications authenticate users.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Additional Downloads

Optional Documentation

Linux PAM Dependencies

Optional

Berkeley DB-5.3.28, libnsl-2.0.0, libtirpc-1.3.2, libaudit, and Prelude

Optional (To Rebuild the Documentation)

docbook-xml-4.5, docbook-xsl-1.79.2, fop-2.7, libxslt-1.1.35 and either Lynx-2.8.9rel.1 or W3m

Note

Shadow-4.11.1 needs to be reinstalled after installing and configuring Linux PAM.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/linux-pam

Installation of Linux PAM

First prevent the installation of an unneeded systemd file:

sed -e /service_DATA/d \
    -i modules/pam_namespace/Makefile.am &&
autoreconf

If you downloaded the documentation, unpack the tarball by issuing the following command.

tar -xf ../Linux-PAM-1.5.2-docs.tar.xz --strip-components=1

If you instead want to regenerate the documentation, fix the configure script so that it detects lynx if installed:

sed -e 's/dummy elinks/dummy lynx/'                                    \
    -e 's/-no-numbering -no-references/-force-html -nonumbers -stdin/' \
    -i configure

Install Linux PAM by running the following commands:

./configure --prefix=/usr                        \
            --sbindir=/usr/sbin                  \
            --sysconfdir=/etc                    \
            --libdir=/usr/lib                    \
            --enable-securedir=/usr/lib/security \
            --docdir=/usr/share/doc/Linux-PAM-1.5.2 &&
make

To test the results, a suitable /etc/pam.d/other configuration file must exist.

Reinstallation or upgrade of Linux PAM

If you have a system with Linux PAM installed and working, be careful when modifying the files in /etc/pam.d, since your system may become totally unusable. If you want to run the tests, you do not need to create another /etc/pam.d/other file. The installed one can be used for that purpose.

You should also be aware that make install overwrites the configuration files in /etc/security as well as /etc/environment. In case you have modified those files, be sure to back them up.

For a first installation, create the configuration file by issuing the following commands as the root user:

install -v -m755 -d /etc/pam.d &&

cat > /etc/pam.d/other << "EOF"
auth     required       pam_deny.so
account  required       pam_deny.so
password required       pam_deny.so
session  required       pam_deny.so
EOF

Now run the tests by issuing make check. Ensure there are no errors produced by the tests before continuing the installation. Note that the checks are quite long. It may be useful to redirect the output to a log file in order to inspect it thoroughly.

Only in case of a first installation, remove the configuration file created earlier by issuing the following command as the root user:

rm -fv /etc/pam.d/other

Now, as the root user:

make install &&
chmod -v 4755 /usr/sbin/unix_chkpwd

Command Explanations

--enable-securedir=/usr/lib/security: This switch sets the installation location for the PAM modules.

--disable-regenerate-docu : If the needed dependencies (docbook-xml-4.5, docbook-xsl-1.79.2, libxslt-1.1.35, and Lynx-2.8.9rel.1 or W3m) are installed, the manual pages, and the html and text documentations are (re)generated and installed. Furthermore, if fop-2.7 is installed, the PDF documentation is generated and installed. Use this switch if you do not want to rebuild the documentation.

chmod -v 4755 /usr/sbin/unix_chkpwd: The unix_chkpwd helper program must be setuid so that non-root processes can access the shadow file.

Configuring Linux-PAM

Config Files

/etc/security/* and /etc/pam.d/*

Configuration Information

Configuration information is placed in /etc/pam.d/. Below is an example file:

# Begin /etc/pam.d/other

auth            required        pam_unix.so     nullok
account         required        pam_unix.so
session         required        pam_unix.so
password        required        pam_unix.so     nullok

# End /etc/pam.d/other

Now set up some generic files. As the root user:

install -vdm755 /etc/pam.d &&
cat > /etc/pam.d/system-account << "EOF" &&
# Begin /etc/pam.d/system-account

account   required    pam_unix.so

# End /etc/pam.d/system-account
EOF

cat > /etc/pam.d/system-auth << "EOF" &&
# Begin /etc/pam.d/system-auth

auth      required    pam_unix.so

# End /etc/pam.d/system-auth
EOF

cat > /etc/pam.d/system-session << "EOF"
# Begin /etc/pam.d/system-session

session   required    pam_unix.so

# End /etc/pam.d/system-session
EOF
cat > /etc/pam.d/system-password << "EOF"
# Begin /etc/pam.d/system-password

# use sha512 hash for encryption, use shadow, and try to use any previously
# defined authentication token (chosen password) set by any prior module
password  required    pam_unix.so       sha512 shadow try_first_pass

# End /etc/pam.d/system-password
EOF

If you wish to enable strong password support, install libpwquality-1.4.4, and follow the instructions in that page to configure the pam_pwquality PAM module with strong password support.

Now add a restrictive /etc/pam.d/other configuration file. With this file, programs that are PAM aware will not run unless a configuration file specifically for that application is created.

cat > /etc/pam.d/other << "EOF"
# Begin /etc/pam.d/other

auth        required        pam_warn.so
auth        required        pam_deny.so
account     required        pam_warn.so
account     required        pam_deny.so
password    required        pam_warn.so
password    required        pam_deny.so
session     required        pam_warn.so
session     required        pam_deny.so

# End /etc/pam.d/other
EOF

The PAM man page (man pam) provides a good starting point for descriptions of fields and allowable entries. The Linux-PAM System Administrators' Guide is recommended for additional information.

Important

You should now reinstall the Shadow-4.11.1 package .

Contents

Installed Program: faillock, mkhomedir_helper, pam_namespace_helper, pam_timestamp_check, pwhistory_helper, unix_chkpwd and unix_update
Installed Libraries: libpam.so, libpamc.so and libpam_misc.so
Installed Directories: /etc/security, /usr/lib/security, /usr/include/security and /usr/share/doc/Linux-PAM-1.5.2

Short Descriptions

faillock

displays and modifies the authentication failure record files

mkhomedir_helper

is a helper binary that creates home directories

pam_namespace_helper

is a helper program used to configure a private namespace for a user session

pwhistory_helper

is a helper program that transfers password hashes from passwd or shadow to opasswd

pam_timestamp_check

is used to check if the default timestamp is valid

unix_chkpwd

is a helper binary that verifies the password of the current user

unix_update

is a helper binary that updates the password of a given user

libpam.so

provides the interfaces between applications and the PAM modules

liboauth-1.0.3

Introduction to liboauth

liboauth is a collection of POSIX-C functions implementing the OAuth Core RFC 5849 standard. Liboauth provides functions to escape and encode parameters according to OAuth specification and offers high-level functionality to sign requests or verify OAuth signatures as well as perform HTTP requests.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Additional Downloads

liboauth Dependencies

Required

cURL-7.83.0

Optional

nss-3.78 and Doxygen-1.9.3 (to build documentation)

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/liboauth

Installation of liboauth

Apply a patch for the current version of openssl:

patch -Np1 -i ../liboauth-1.0.3-openssl-1.1.0-3.patch

Install liboauth by running the following commands:

./configure --prefix=/usr --disable-static &&
make

If you wish to build the documentation (needs Doxygen-1.9.3), issue:

make dox

To test the results, issue: make check.

Now, as the root user:

make install

If you have previously built the documentation, install it by running the following commands as the root user:

install -v -dm755 /usr/share/doc/liboauth-1.0.3 &&
cp -rv doc/html/* /usr/share/doc/liboauth-1.0.3

Command Explanations

--disable-static: This switch prevents installation of static versions of the libraries.

--enable-nss: Use this switch if you want to use Mozilla NSS instead of OpenSSL.

Contents

Installed Programs: None
Installed Libraries: liboauth.so
Installed Directories: /usr/share/doc/liboauth-1.0.3

Short Descriptions

liboauth.so

provides functions to escape and encode stings according to OAuth specifications and offers high-level functionality built on top to sign requests or verify signatures using either NSS or OpenSSL for calculating the hash/signatures

libpwquality-1.4.4

Introduction to libpwquality

The libpwquality package provides common functions for password quality checking and also scoring them based on their apparent randomness. The library also provides a function for generating random passwords with good pronounceability.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

libpwquality Dependencies

Required

CrackLib-2.9.7

Recommended

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/libpwquality

Installation of libpwquality

Install libpwquality by running the following commands:

./configure --prefix=/usr                      \
            --disable-static                   \
            --with-securedir=/usr/lib/security \
            --with-python-binary=python3       &&
make

This package does not come with a test suite.

Now, as the root user:

make install

Command Explanations

--with-python-binary=python3: This parameter gives the location of the Python binary. The default is python, and requires Python-2.7.18.

Configuring libpwquality

libpwquality is intended to be a functional replacement for the now-obsolete pam_cracklib.so PAM module. To configure the system to use the pam_pwquality module, execute the following commands as the root user:

mv /etc/pam.d/system-password{,.orig} &&
cat > /etc/pam.d/system-password << "EOF"
# Begin /etc/pam.d/system-password

# check new passwords for strength (man pam_pwquality)
password  required    pam_pwquality.so   authtok_type=UNIX retry=1 difok=1 \
                                         minlen=8 dcredit=0 ucredit=0 \
                                         lcredit=0 ocredit=0 minclass=1 \
                                         maxrepeat=0 maxsequence=0 \
                                         maxclassrepeat=0 geoscheck=0 \
                                         dictcheck=1 usercheck=1 \
                                         enforcing=1 badwords="" \
                                         dictpath=/usr/lib/cracklib/pw_dict
# use sha512 hash for encryption, use shadow, and use the
# authentication token (chosen password) set by pam_pwquality
# above (or any previous modules)
password  required    pam_unix.so        sha512 shadow use_authtok

# End /etc/pam.d/system-password
EOF

Contents

Installed Programs: pwscore and pwmake
Installed Libraries: pam_pwquality.so and libpwquality.so
Installed Directories: None

Short Descriptions

pwmake

is a simple configurable tool for generating random and relatively easily pronounceable passwords

pwscore

is a simple tool for checking quality of a password

libpwquality.so

contains API functions for checking the password quality

pam_pwquality.so

is a Linux PAM module used to perform password quality checking

MIT Kerberos V5-1.19.3

Introduction to MIT Kerberos V5

MIT Kerberos V5 is a free implementation of Kerberos 5. Kerberos is a network authentication protocol. It centralizes the authentication database and uses kerberized applications to work with servers or services that support Kerberos allowing single logins and encrypted communication over internal networks or the Internet.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

  • Download (HTTP): https://kerberos.org/dist/krb5/1.19/krb5-1.19.3.tar.gz

  • Download MD5 sum: 37722be6228da68ea83a008f782c7f53

  • Download size: 8.3 MB

  • Estimated disk space required: 132 MB (add 15 MB for tests)

  • Estimated build time: 0.6 SBU (Using parallelism=4; add 0.8 SBU for tests)

Additional Downloads

MIT Kerberos V5 Dependencies

Optional

BIND Utilities-9.18.2, GnuPG-2.3.6 (to authenticate the package), keyutils-1.6.1, OpenLDAP-2.6.2, Valgrind-3.19.0 (used during the testsuite), yasm-1.3.0, libedit, cmocka, pyrad, and resolv_wrapper

Note

Some sort of time synchronization facility on your system (like ntp-4.2.8p15) is required since Kerberos won't authenticate if there is a time difference between a kerberized client and the KDC server.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/mitkrb

Installation of MIT Kerberos V5

Next, fix several issues identified by OpenSSL-3:

patch -Np1 -i ../mitkrb-1.19.3-openssl3_fixes-1.patch

Build MIT Kerberos V5 by running the following commands:

cd src &&

sed -i -e 's@\^u}@^u cols 300}@' tests/dejagnu/config/default.exp     &&
sed -i -e '/eq 0/{N;s/12 //}'    plugins/kdb/db2/libdb2/test/run.test &&
sed -i '/t_iprop.py/d'           tests/Makefile.in                    &&

autoreconf -fiv &&

./configure --prefix=/usr            \
            --sysconfdir=/etc        \
            --localstatedir=/var/lib \
            --runstatedir=/run       \
            --with-system-et         \
            --with-system-ss         \
            --with-system-verto=no   \
            --enable-dns-for-realm &&
make

To test the build, issue as the root user: make -k -j1 check. If you have a former version of MIT Kerberos V5 installed, it may happen that the test suite may pick up the installed versions of the libraries, rather than the newly built ones. If so, it is better to run the tests after the installation. Some tests may fail with the latest version of dejagnu and glibc.

Now, as the root user:

make install &&

install -v -dm755 /usr/share/doc/krb5-1.19.3 &&
cp -vfr ../doc/*  /usr/share/doc/krb5-1.19.3

Command Explanations

The first sed increases the width of the virtual terminal used for some tests to prevent some spurious text in the output which is taken as a failure. The second sed removes a test that is known to fail. The third sed removes a test that is known to hang.

--localstatedir=/var/lib: This option is used so that the Kerberos variable runtime data is located in /var/lib instead of /usr/var.

--runstatedir=/run: This option is used so that the Kerberos runtime state information is located in /run instead of the deprecated /var/run.

--with-system-et: This switch causes the build to use the system-installed versions of the error-table support software.

--with-system-ss: This switch causes the build to use the system-installed versions of the subsystem command-line interface software.

--with-system-verto=no: This switch fixes a bug in the package: it does not recognize its own verto library installed previously. This is not a problem, if reinstalling the same version, but if you are updating, the old library is used as system's one, instead of installing the new version.

--enable-dns-for-realm: This switch allows realms to be resolved using the DNS server.

--with-ldap: Use this switch if you want to compile the OpenLDAP database backend module.

Configuring MIT Kerberos V5

Config Files

/etc/krb5.conf and /var/lib/krb5kdc/kdc.conf

Configuration Information

Kerberos Configuration

Tip

You should consider installing some sort of password checking dictionary so that you can configure the installation to only accept strong passwords. A suitable dictionary to use is shown in the CrackLib-2.9.7 instructions. Note that only one file can be used, but you can concatenate many files into one. The configuration file shown below assumes you have installed a dictionary to /usr/share/dict/words.

Create the Kerberos configuration file with the following commands issued by the root user:

cat > /etc/krb5.conf << "EOF"
# Begin /etc/krb5.conf

[libdefaults]
    default_realm = <EXAMPLE.ORG>
    encrypt = true

[realms]
    <EXAMPLE.ORG> = {
        kdc = <belgarath.example.org>
        admin_server = <belgarath.example.org>
        dict_file = /usr/share/dict/words
    }

[domain_realm]
    .<example.org> = <EXAMPLE.ORG>

[logging]
    kdc = SYSLOG:INFO:AUTH
    admin_server = SYSLOG:INFO:AUTH
    default = SYSLOG:DEBUG:DAEMON

# End /etc/krb5.conf
EOF

You will need to substitute your domain and proper hostname for the occurrences of the <belgarath> and <example.org> names.

default_realm should be the name of your domain changed to ALL CAPS. This isn't required, but both Heimdal and MIT recommend it.

encrypt = true provides encryption of all traffic between kerberized clients and servers. It's not necessary and can be left off. If you leave it off, you can encrypt all traffic from the client to the server using a switch on the client program instead.

The [realms] parameters tell the client programs where to look for the KDC authentication services.

The [domain_realm] section maps a domain to a realm.

Create the KDC database:

kdb5_util create -r <EXAMPLE.ORG> -s

Now you should populate the database with principals (users). For now, just use your regular login name or root.

kadmin.local
kadmin.local: add_policy dict-only
kadmin.local: addprinc -policy dict-only <loginname>

The KDC server and any machine running kerberized server daemons must have a host key installed:

kadmin.local: addprinc -randkey host/<belgarath.example.org>

After choosing the defaults when prompted, you will have to export the data to a keytab file:

kadmin.local: ktadd host/<belgarath.example.org>

This should have created a file in /etc named krb5.keytab (Kerberos 5). This file should have 600 (root rw only) permissions. Keeping the keytab files from public access is crucial to the overall security of the Kerberos installation.

Exit the kadmin program (use quit or exit) and return back to the shell prompt. Start the KDC daemon manually, just to test out the installation:

/usr/sbin/krb5kdc

Attempt to get a ticket with the following command:

kinit <loginname>

You will be prompted for the password you created. After you get your ticket, you can list it with the following command:

klist

Information about the ticket should be displayed on the screen.

To test the functionality of the keytab file, issue the following command as the root user:

ktutil
ktutil: rkt /etc/krb5.keytab
ktutil: l

This should dump a list of the host principal, along with the encryption methods used to access the principal.

Create an empty ACL file that can be modified later:

touch /var/lib/krb5kdc/kadm5.acl

At this point, if everything has been successful so far, you can feel fairly confident in the installation and configuration of the package.

Additional Information

For additional information consult the documentation for krb5-1.19.3 on which the above instructions are based.

Init Script

If you want to start Kerberos services at boot, install the /etc/rc.d/init.d/krb5 init script included in the blfs-bootscripts-20210826 package using the following command:

make install-krb5

Contents

Installed Programs: gss-client, gss-server, k5srvutil, kadmin, kadmin.local, kadmind, kdb5_ldap_util (optional), kdb5_util, kdestroy, kinit, klist, kpasswd, kprop, kpropd, kproplog, krb5-config, krb5-send-pr, krb5kdc, ksu, kswitch, ktutil, kvno, sclient, sim_client, sim_server, sserver, uuclient, and uuserver
Installed Libraries: libgssapi_krb5.so, libgssrpc.so, libk5crypto.so, libkadm5clnt_mit.so, libkadm5clnt.so, libkadm5srv_mit.so, libkadm5srv.so, libkdb_ldap.so (optional), libkdb5.so, libkrad.so, libkrb5.so, libkrb5support.so, libverto.so, and some plugins under the /usr/lib/krb5 tree
Installed Directories: /usr/include/{gssapi,gssrpc,kadm5,krb5}, /usr/lib/krb5, /usr/share/{doc/krb5-1.19.3,examples/krb5}, /var/lib/krb5kdc, and /run/krb5kdc

Short Descriptions

gss-client

is a GSSAPI test client

gss-server

is a GSSAPI test server

k5srvutil

is a host keytable manipulation utility

kadmin

is an utility used to make modifications to the Kerberos database

kadmin.local

is an utility similar to kadmin, but if the database is db2, the local client kadmin.local, is intended to run directly on the master KDC without Kerberos authentication

kadmind

is a server for administrative access to a Kerberos database

kdb5_ldap_util (optional)

allows an administrator to manage realms, Kerberos services and ticket policies

kdb5_util

is the KDC database utility

kdestroy

removes the current set of tickets

kinit

is used to authenticate to the Kerberos server as a principal and acquire a ticket granting ticket that can later be used to obtain tickets for other services

klist

reads and displays the current tickets in the credential cache

kpasswd

is a program for changing Kerberos 5 passwords

kprop

takes a principal database in a specified format and converts it into a stream of database records

kpropd

receives a database sent by kprop and writes it as a local database

kproplog

displays the contents of the KDC database update log to standard output

krb5-config

gives information on how to link programs against libraries

krb5kdc

is the Kerberos 5 server

krb5-send-pr

sends a problem report (PR) to a central support site

ksu

is the super user program using Kerberos protocol. Requires a properly configured /etc/shells and ~/.k5login containing principals authorized to become super users

kswitch

makes the specified credential cache the primary cache for the collection, if a cache collection is available

ktutil

is a program for managing Kerberos keytabs

kvno

prints keyversion numbers of Kerberos principals

sclient

is used to contact a sample server and authenticate to it using Kerberos 5 tickets, then display the server's response

sim_client

is a simple UDP-based sample client program, for demonstration

sim_server

is a simple UDP-based server application, for demonstration

sserver

is the sample Kerberos 5 server

uuclient

is another sample client

uuserver

is another sample server

libgssapi_krb5.so

contains the Generic Security Service Application Programming Interface (GSSAPI) functions which provides security services to callers in a generic fashion, supportable with a range of underlying mechanisms and technologies and hence allowing source-level portability of applications to different environments

libkadm5clnt.so

contains the administrative authentication and password checking functions required by Kerberos 5 client-side programs

libkadm5srv.so

contains the administrative authentication and password checking functions required by Kerberos 5 servers

libkdb5.so

is a Kerberos 5 authentication/authorization database access library

libkrad.so

contains the internal support library for RADIUS functionality

libkrb5.so

is an all-purpose Kerberos 5 library

Nettle-3.7.3

Introduction to Nettle

The Nettle package contains a low-level cryptographic library that is designed to fit easily in many contexts.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Nettle Dependencies

Optional

Valgrind-3.19.0 (optional for the tests)

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/nettle

Installation of Nettle

Install Nettle by running the following commands:

./configure --prefix=/usr --disable-static &&
make

To test the results, issue: make check.

Now, as the root user:

make install &&
chmod   -v   755 /usr/lib/lib{hogweed,nettle}.so &&
install -v -m755 -d /usr/share/doc/nettle-3.7.3 &&
install -v -m644 nettle.html /usr/share/doc/nettle-3.7.3

Command Explanations

--disable-static: This switch prevents installation of static versions of the libraries.

Contents

Installed Programs: nettle-hash, nettle-lfib-stream, nettle-pbkdf2, pkcs1-conv and sexp-conv
Installed Libraries: libhogweed.so and libnettle.so
Installed Directory: /usr/include/nettle and /usr/share/doc/nettle-3.7.3

Short Descriptions

nettle-hash

calculates a hash value using a specified algorithm

nettle-lfib-stream

outputs a sequence of pseudorandom (non-cryptographic) bytes, using Knuth's lagged fibonacci generator. The stream is useful for testing, but should not be used to generate cryptographic keys or anything else that needs real randomness

nettle-pbkdf2

is a password-based key derivation function that takes a password or a passphrase as input and returns a strengthened password, which is protected against pre-computation attacks by using salting and other expensive computations.

pkcs1-conv

converts private and public RSA keys from PKCS #1 format to sexp format

sexp-conv

converts an s-expression to a different encoding

NSS-3.78

Introduction to NSS

The Network Security Services (NSS) package is a set of libraries designed to support cross-platform development of security-enabled client and server applications. Applications built with NSS can support SSL v2 and v3, TLS, PKCS #5, PKCS #7, PKCS #11, PKCS #12, S/MIME, X.509 v3 certificates, and other security standards. This is useful for implementing SSL and S/MIME or other Internet security standards into an application.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Additional Downloads

NSS Dependencies

Required

NSPR-4.33

Recommended

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/nss

Installation of NSS

Install NSS by running the following commands:

patch -Np1 -i ../nss-3.78-standalone-1.patch &&

cd nss &&

make BUILD_OPT=1                  \
  NSPR_INCLUDE_DIR=/usr/include/nspr  \
  USE_SYSTEM_ZLIB=1                   \
  ZLIB_LIBS=-lz                       \
  NSS_ENABLE_WERROR=0                 \
  $([ $(uname -m) = x86_64 ] && echo USE_64=1) \
  $([ -f /usr/include/sqlite3.h ] && echo NSS_USE_SYSTEM_SQLITE=1)

To run the tests, execute the following commands:

cd tests &&
HOST=localhost DOMSUF=localdomain ./all.sh
cd ../

Note

Some information about the tests:

  • HOST=localhost and DOMSUF=localdomain are required. Without these variables, a FQDN is required to be specified and this generic way should work for everyone, provided localhost.localdomain is defined in /etc/hosts, as done in the lfs book.

  • The tests take an extremely long time to run. If desired there is information in the all.sh script about running subsets of the total test suite.

  • When interrupting the tests, the test suite fails to spin down test servers that are run. This leads to an infinite loop in the tests where the test suite tries to kill a server that doesn't exist anymore because it pulls the wrong PID.

  • Test suite results (in HTML format!) can be found at ../../test_results/security/localhost.1/results.html

Now, as the root user:

cd ../dist                                                          &&

install -v -m755 Linux*/lib/*.so              /usr/lib              &&
install -v -m644 Linux*/lib/{*.chk,libcrmf.a} /usr/lib              &&

install -v -m755 -d                           /usr/include/nss      &&
cp -v -RL {public,private}/nss/*              /usr/include/nss      &&
chmod -v 644                                  /usr/include/nss/*    &&

install -v -m755 Linux*/bin/{certutil,nss-config,pk12util} /usr/bin &&

install -v -m644 Linux*/lib/pkgconfig/nss.pc  /usr/lib/pkgconfig

Command Explanations

BUILD_OPT=1: This option is passed to make so that the build is performed with no debugging symbols built into the binaries and the default compiler optimizations are used.

NSPR_INCLUDE_DIR=/usr/include/nspr: This option sets the location of the nspr headers.

USE_SYSTEM_ZLIB=1: This option is passed to make to ensure that the libssl3.so library is linked to the system installed zlib instead of the in-tree version.

ZLIB_LIBS=-lz: This option provides the linker flags needed to link to the system zlib.

$([ $(uname -m) = x86_64 ] && echo USE_64=1): The USE_64=1 option is required on x86_64, otherwise make will try (and fail) to create 32-bit objects. The [ $(uname -m) = x86_64 ] test ensures it has no effect on a 32 bit system.

([ -f /usr/include/sqlite3.h ] && echo NSS_USE_SYSTEM_SQLITE=1): This tests if sqlite is installed and if so it echos the option NSS_USE_SYSTEM_SQLITE=1 to make so that libsoftokn3.so will link against the system version of sqlite.

NSS_DISABLE_GTESTS=1: If you don't need to run NSS test suite, append this option to make command, to prevent the compilation of tests and save some build time.

Configuring NSS

If p11-kit-0.24.1 is installed, the p11-kit trust module (/usr/lib/pkcs11/p11-kit-trust.so) can be used as a drop-in replacement for /usr/lib/libnssckbi.so to transparently make the system CAs available to NSS aware applications, rather than the static list provided by /usr/lib/libnssckbi.so. As the root user, execute the following commands:

ln -sfv ./pkcs11/p11-kit-trust.so /usr/lib/libnssckbi.so

Additionally, for dependent applications that do not use the internal database (/usr/lib/libnssckbi.so), the /usr/sbin/make-ca script included on the make-ca-1.10 page can generate a system wide NSS DB with the -n switch, or by modifying the /etc/make-ca/make-ca.conf file.

Contents

Installed Programs: certutil, nss-config, and pk12util
Installed Libraries: libcrmf.a, libfreebl3.so, libfreeblpriv3.so, libnss3.so, libnssckbi.so, libnssckbi-testlib.so, libnssdbm3.so, libnsssysinit.so, libnssutil3.so, libpkcs11testmodule.so, libsmime3.so, libsoftokn3.so, and libssl3.so
Installed Directories: /usr/include/nss

Short Descriptions

certutil

is the Mozilla Certificate Database Tool. It is a command-line utility that can create and modify the Netscape Communicator cert8.db and key3.db database files. It can also list, generate, modify, or delete certificates within the cert8.db file and create or change the password, generate new public and private key pairs, display the contents of the key database, or delete key pairs within the key3.db file

nss-config

is used to determine the NSS library settings of the installed NSS libraries

pk12util

is a tool for importing certificates and keys from pkcs #12 files into NSS or exporting them. It can also list certificates and keys in such files

OpenSSH-9.0p1

Introduction to OpenSSH

The OpenSSH package contains ssh clients and the sshd daemon. This is useful for encrypting authentication and subsequent traffic over a network. The ssh and scp commands are secure implementations of telnet and rcp respectively.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

OpenSSH Dependencies

Optional

GDB-12.1 (for tests), Linux-PAM-1.5.2, a graphical environment, MIT Kerberos V5-1.19.3, Which-2.21 (for tests), libedit, LibreSSL Portable, OpenSC, and libsectok

Optional Runtime (Used only to gather entropy)

Net-tools-2.10, and Sysstat-12.5.6

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/OpenSSH

Installation of OpenSSH

OpenSSH runs as two processes when connecting to other computers. The first process is a privileged process and controls the issuance of privileges as necessary. The second process communicates with the network. Additional installation steps are necessary to set up the proper environment, which are performed by issuing the following commands as the root user:

install  -v -m700 -d /var/lib/sshd &&
chown    -v root:sys /var/lib/sshd &&

groupadd -g 50 sshd        &&
useradd  -c 'sshd PrivSep' \
         -d /var/lib/sshd  \
         -g sshd           \
         -s /bin/false     \
         -u 50 sshd

Install OpenSSH by running the following commands:

./configure --prefix=/usr                            \
            --sysconfdir=/etc/ssh                    \
            --with-privsep-path=/var/lib/sshd        \
            --with-default-path=/usr/bin             \
            --with-superuser-path=/usr/sbin:/usr/bin \
            --with-pid-dir=/run                      &&
make

The testsuite requires an installed copy of scp to complete the multiplexing tests. To run the test suite, first copy the scp program to /usr/bin, making sure that you backup any existing copy first.

To test the results, issue: make -j1 tests.

Now, as the root user:

make install &&
install -v -m755    contrib/ssh-copy-id /usr/bin     &&

install -v -m644    contrib/ssh-copy-id.1 \
                    /usr/share/man/man1              &&
install -v -m755 -d /usr/share/doc/openssh-9.0p1     &&
install -v -m644    INSTALL LICENCE OVERVIEW README* \
                    /usr/share/doc/openssh-9.0p1

Command Explanations

--sysconfdir=/etc/ssh: This prevents the configuration files from being installed in /usr/etc.

--with-default-path=/usr/bin and --with-superuser-path=/usr/sbin:/usr/bin: These set PATH consistent with LFS and BLFS Shadow package.

--with-pid-dir=/run: This prevents OpenSSH from referring to deprecated /var/run.

--with-pam: This parameter enables Linux-PAM support in the build.

--with-xauth=/usr/bin/xauth: Set the default location for the xauth binary for X authentication. Change the location if xauth will be installed to a different path. This can also be controlled from sshd_config with the XAuthLocation keyword. You can omit this switch if Xorg is already installed.

--with-kerberos5=/usr: This option is used to include Kerberos 5 support in the build.

--with-libedit: This option enables line editing and history features for sftp.

Configuring OpenSSH

Config Files

~/.ssh/*, /etc/ssh/ssh_config, and /etc/ssh/sshd_config

There are no required changes to any of these files. However, you may wish to view the /etc/ssh/ files and make any changes appropriate for the security of your system. One recommended change is that you disable root login via ssh. Execute the following command as the root user to disable root login via ssh:

echo "PermitRootLogin no" >> /etc/ssh/sshd_config

If you want to be able to log in without typing in your password, first create ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub with ssh-keygen and then copy ~/.ssh/id_rsa.pub to ~/.ssh/authorized_keys on the remote computer that you want to log into. You'll need to change REMOTE_USERNAME and REMOTE_HOSTNAME for the username and hostname of the remote computer and you'll also need to enter your password for the ssh-copy-id command to succeed:

ssh-keygen &&
ssh-copy-id -i ~/.ssh/id_rsa.pub REMOTE_USERNAME@REMOTE_HOSTNAME

Once you've got passwordless logins working it's actually more secure than logging in with a password (as the private key is much longer than most people's passwords). If you would like to now disable password logins, as the root user:

echo "PasswordAuthentication no" >> /etc/ssh/sshd_config &&
echo "KbdInteractiveAuthentication no" >> /etc/ssh/sshd_config

If you added Linux-PAM support and you want ssh to use it then you will need to add a configuration file for sshd and enable use of LinuxPAM. Note, ssh only uses PAM to check passwords, if you've disabled password logins these commands are not needed. If you want to use PAM, issue the following commands as the root user:

sed 's@d/login@d/sshd@g' /etc/pam.d/login > /etc/pam.d/sshd &&
chmod 644 /etc/pam.d/sshd &&
echo "UsePAM yes" >> /etc/ssh/sshd_config

Additional configuration information can be found in the man pages for sshd, ssh and ssh-agent.

Boot Script

To start the SSH server at system boot, install the /etc/rc.d/init.d/sshd init script included in the blfs-bootscripts-20210826 package.

make install-sshd

Contents

Installed Programs: scp, sftp, ssh, ssh-add, ssh-agent, ssh-copy-id, ssh-keygen, ssh-keyscan, and sshd
Installed Libraries: None
Installed Directories: /etc/ssh, /usr/share/doc/openssh-9.0p1, and /var/lib/sshd

Short Descriptions

scp

is a file copy program that acts like rcp except it uses an encrypted protocol

sftp

is an FTP-like program that works over the SSH1 and SSH2 protocols

ssh

is an rlogin/rsh-like client program except it uses an encrypted protocol

sshd

is a daemon that listens for ssh login requests

ssh-add

is a tool which adds keys to the ssh-agent

ssh-agent

is an authentication agent that can store private keys

ssh-copy-id

is a script that enables logins on remote machines using local keys

ssh-keygen

is a key generation tool

ssh-keyscan

is a utility for gathering public host keys from a number of hosts

p11-kit-0.24.1

Introduction to p11-kit

The p11-kit package provides a way to load and enumerate PKCS #11 (a Cryptographic Token Interface Standard) modules.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

p11-kit Dependencies

Recommended
Optional

GTK-Doc-1.33.2, libxslt-1.1.35, and nss-3.78 (runtime)

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/p11-kit

Installation of p11-kit

Prepare the distribution specific anchor hook:

sed '20,$ d' -i trust/trust-extract-compat &&
cat >> trust/trust-extract-compat << "EOF"
# Copy existing anchor modifications to /etc/ssl/local
/usr/libexec/make-ca/copy-trust-modifications

# Update trust stores
/usr/sbin/make-ca -r
EOF

Install p11-kit by running the following commands:

mkdir p11-build &&
cd    p11-build &&

meson --prefix=/usr       \
      --buildtype=release \
      -Dtrust_paths=/etc/pki/anchors &&
ninja

To test the results, issue: ninja test.

Now, as the root user:

ninja install &&
ln -sfv /usr/libexec/p11-kit/trust-extract-compat \
        /usr/bin/update-ca-certificates

Command Explanations

--buildtype=release: Specify a buildtype suitable for stable releases of the package, as the default may produce unoptimized binaries.

-Dtrust_paths=/etc/pki/anchors: this switch sets the location of trusted certificates used by libp11-kit.so.

-Dhash_impl=freebl: Use this switch if you want to use the Freebl library from NSS for SHA1 and MD5 hashing.

-Dgtk_doc=true: Use this switch if you have installed GTK-Doc-1.33.2 and libxslt-1.1.35 and wish to rebuild the documentation and generate manual pages.

Configuring p11-kit

The p11-kit trust module (/usr/lib/pkcs11/p11-kit-trust.so) can be used as a drop-in replacement for /usr/lib/libnssckbi.so to transparently make the system CAs available to NSS aware applications, rather than the static list provided by /usr/lib/libnssckbi.so. As the root user, execute the following commands:

ln -sfv ./pkcs11/p11-kit-trust.so /usr/lib/libnssckbi.so

Contents

Installed Programs: p11-kit, trust, and update-ca-certificates
Installed Libraries: libp11-kit.so and p11-kit-proxy.so
Installed Directories: /etc/pkcs11, /usr/include/p11-kit-1, /usr/lib/pkcs11, /usr/libexec/p11-kit, /usr/share/gtk-doc/html/p11-kit, and /usr/share/p11-kit

Short Descriptions

p11-kit

is a command line tool that can be used to perform operations on PKCS#11 modules configured on the system

trust

is a command line tool to examine and modify the shared trust policy store

update-ca-certificates

is a command line tool to both extract local certificates from an updated anchor store, and regenerate all anchors and certificate stores on the system. This is done unconditionally on BLFS using the --force and --get flags to make-ca and should likely not be used for automated updates

libp11-kit.so

contains functions used to coordinate initialization and finalization of any PKCS#11 module

p11-kit-proxy.so

is the PKCS#11 proxy module

Polkit-0.120

Introduction to Polkit

Polkit is a toolkit for defining and handling authorizations. It is used for allowing unprivileged processes to communicate with privileged processes.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Additional Downloads

Polkit Dependencies

Required

GLib-2.72.1 and JS-91.9.0

Recommended

Note

Since elogind uses PAM to register user sessions, it is a good idea to build Polkit with PAM support so elogind can track Polkit sessions.

Optional

D-Bus Python-1.2.18 and dbusmock-0.27.5 (both needed for tests), and GTK-Doc-1.33.2

Optional Runtime Dependencies

One polkit authentication agent for using polkit in the graphical environment: polkit-kde-agent in Plasma-5.24.0 for KDE, the agent built in gnome-shell-42.0 for GNOME3, polkit-gnome-0.105 for XFCE, and lxpolkit in LXSession-0.5.5 for LXDE.

Note

If libxslt-1.1.35 is installed, then docbook-xml-4.5 and docbook-xsl-1.79.2 are required. If you have installed libxslt-1.1.35, but you do not want to install any of the DocBook packages mentioned, you will need to use -Dman=false in the instructions below.

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/polkit

Installation of Polkit

There should be a dedicated user and group to take control of the polkitd daemon after it is started. Issue the following commands as the root user:

groupadd -fg 27 polkitd &&
useradd -c "PolicyKit Daemon Owner" -d /etc/polkit-1 -u 27 \
        -g polkitd -s /bin/false polkitd

First, fix problems with setting permissions during installation and with meson-0.60.0:

sed '/0,/s/^/#/' -i meson_post_install.py &&
sed '/policy,/d' -i actions/meson.build \
                 -i src/examples/meson.build

Apply a patch to fix two security issues:

patch -Np1 -i ../polkit-0.120-security_fixes-1.patch

Port this package to use JS-91:

patch -Np1 -i ../polkit-0.120-js91-1.patch

Install Polkit by running the following commands:

mkdir build &&
cd    build &&

meson --prefix=/usr                 \
      --buildtype=release           \
      -Dman=true                    \
      -Dsession_tracking=libelogind \
      -Dsystemdsystemunitdir=/tmp   \
      -Dtests=true   \
      ..                            &&
ninja

To test the results, first ensure that the system D-Bus daemon is running, and both D-Bus Python-1.2.18 and dbusmock-0.27.5 are installed. Then run meson test -t3.

Now, as the root user:

ninja install &&
rm -v /tmp/*.service

Command Explanations

--buildtype=release: Specify a buildtype suitable for stable releases of the package, as the default may produce unoptimized binaries.

-Dtests=true: This switch allows to run the test suite of this package. As Polkit is used for authorizations, its integrity can affect system security. So it's recommended to run the test suite building this package.

-Dauthfw=shadow: This switch enables the package to use the Shadow rather than the Linux PAM Authentication framework. Use it if you have not installed Linux PAM.

-Dintrospection=false: Use this option if you are certain that you do not need gobject-introspection files for polkit, or do not have gobject-introspection installed.

-Dman=false: Use this option to disable generating and installing manual pages. This is useful if libxslt is not installed.

-Dexamples=true: Use this option to build the example programs.

-Dgtk_doc=true: Use this option to enable building and installing the API documentation.

Configuring Polkit

PAM Configuration

Note

If you did not build Polkit with Linux PAM support, you can skip this section.

If you have built Polkit with Linux PAM support, you need to modify the default PAM configuration file which was installed by default to get Polkit to work correctly with BLFS. Issue the following commands as the root user to create the configuration file for Linux PAM:

cat > /etc/pam.d/polkit-1 << "EOF"
# Begin /etc/pam.d/polkit-1

auth     include        system-auth
account  include        system-account
password include        system-password
session  include        system-session

# End /etc/pam.d/polkit-1
EOF

Contents

Installed Programs: pkaction, pkcheck, pkexec, pkttyagent and polkitd
Installed Libraries: libpolkit-agent-1.so and libpolkit-gobject-1.so
Installed Directories: /etc/polkit-1, /usr/include/polkit-1, /usr/lib/polkit-1, /usr/share/gtk-doc/html/polkit-1 and /usr/share/polkit-1

Short Descriptions

pkaction

is used to obtain information about registered PolicyKit actions

pkcheck

is used to check whether a process is authorized for action

pkexec

allows an authorized user to execute a command as another user

pkttyagent

is used to start a textual authentication agent for the subject

polkitd

provides the org.freedesktop.PolicyKit1 D-Bus service on the system message bus

libpolkit-agent-1.so

contains the Polkit authentication agent API functions

libpolkit-gobject-1.so

contains the Polkit authorization API functions

polkit-gnome-0.105

Introduction to Polkit GNOME

The Polkit GNOME package provides an Authentication Agent for Polkit that integrates well with the GNOME Desktop environment.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Additional Downloads

Polkit GNOME Dependencies

Required

AccountsService-22.08.8, GTK+-3.24.33, and Polkit-0.120

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/polkit-gnome

Installation of Polkit GNOME

First, apply some fixes that allow for the proper user icon to be used, as well as some security fixes:

patch -Np1 -i ../polkit-gnome-0.105-consolidated_fixes-1.patch

Install Polkit GNOME by running the following commands:

./configure --prefix=/usr &&
make

This package does not come with a test suite.

Now, as the root user:

make install

Configuring Polkit GNOME

Automatic Startup

For the authentification framework to work, polkit-gnome-authentification-agent-1 needs to be started. However, make install did not install a startup file for the Polkit GNOME so you have to create it by yourself.

Issue the following commands as the root user to create a startup file for Polkit GNOME:

mkdir -p /etc/xdg/autostart &&
cat > /etc/xdg/autostart/polkit-gnome-authentication-agent-1.desktop << "EOF"
[Desktop Entry]
Name=PolicyKit Authentication Agent
Comment=PolicyKit Authentication Agent
Exec=/usr/libexec/polkit-gnome-authentication-agent-1
Terminal=false
Type=Application
Categories=
NoDisplay=true
OnlyShowIn=GNOME;XFCE;Unity;
AutostartCondition=GNOME3 unless-session gnome
EOF

Contents

Installed Program: polkit-gnome-authentication-agent-1
Installed Libraries: None
Installed Directory: None

Short Descriptions

polkit-gnome-authentication-agent-1

is the Polkit authentication agent

Shadow-4.11.1

Introduction to Shadow

Shadow was indeed installed in LFS and there is no reason to reinstall it unless you installed CrackLib or Linux-PAM after your LFS system was completed. If you have installed CrackLib after LFS, then reinstalling Shadow will enable strong password support. If you have installed Linux-PAM, reinstalling Shadow will allow programs such as login and su to utilize PAM.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Shadow Dependencies

Required

Linux-PAM-1.5.2 or CrackLib-2.9.7

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/shadow

Installation of Shadow

Important

The installation commands shown below are for installations where Linux-PAM has been installed and Shadow is being reinstalled to support the Linux-PAM installation.

If you are reinstalling Shadow to provide strong password support using the CrackLib library without using Linux-PAM, ensure you add the --with-libcrack parameter to the configure script below and also issue the following command:

sed -i 's@DICTPATH.*@DICTPATH\t/lib/cracklib/pw_dict@' etc/login.defs

Reinstall Shadow by running the following commands:

sed -i 's/groups$(EXEEXT) //' src/Makefile.in          &&

find man -name Makefile.in -exec sed -i 's/groups\.1 / /'   {} \; &&
find man -name Makefile.in -exec sed -i 's/getspnam\.3 / /' {} \; &&
find man -name Makefile.in -exec sed -i 's/passwd\.5 / /'   {} \; &&

sed -e 's@#ENCRYPT_METHOD DES@ENCRYPT_METHOD SHA512@' \
    -e 's@/var/spool/mail@/var/mail@'                 \
    -e '/PATH=/{s@/sbin:@@;s@/bin:@@}'                \
    -i etc/login.defs                                 &&

./configure --sysconfdir=/etc               \
            --disable-static                \
            --with-group-name-max-length=32 &&
make

This package does not come with a test suite.

Now, as the root user:

make exec_prefix=/usr install

The man pages were installed in LFS, but if reinstallation is desired, run (as the root user):

make -C man install-man

Command Explanations

sed -i 's/groups$(EXEEXT) //' src/Makefile.in: This sed is used to suppress the installation of the groups program as the version from the Coreutils package installed during LFS is preferred.

find man -name Makefile.in -exec ... {} \;: The first command is used to suppress the installation of the groups man pages so the existing ones installed from the Coreutils package are not replaced. The two other commands prevent installation of manual pages that are already installed by Man-pages in LFS.

sed -e 's@#ENCRYPT_METHOD DES@ENCRYPT_METHOD SHA512@' -e 's@/var/spool/mail@/var/mail@' -e '/PATH=/{s@/sbin:@@;s@/bin:@@}' -i etc/login.defs: Instead of using the default 'DES' method, this command modifies the installation to use the more secure 'SHA512' method of hashing passwords, which also allows passwords longer than eight characters. It also changes the obsolete /var/spool/mail location for user mailboxes that Shadow uses by default to the /var/mail location. It also changes the default path to be consistent with that set in LFS.

--with-group-name-max-length=32: The maximum user name is 32 characters. Make the maximum group name the same.

Configuring Linux-PAM to Work with Shadow

Note

The rest of this page is devoted to configuring Shadow to work properly with Linux-PAM. If you do not have Linux-PAM installed, and you reinstalled Shadow to support strong passwords via the CrackLib library, no further configuration is required.

Config Files

/etc/pam.d/* or alternatively /etc/pam.conf, /etc/login.defs and /etc/security/*

Configuration Information

Configuring your system to use Linux-PAM can be a complex task. The information below will provide a basic setup so that Shadow's login and password functionality will work effectively with Linux-PAM. Review the information and links on the Linux-PAM-1.5.2 page for further configuration information. For information specific to integrating Shadow, Linux-PAM and libpwquality, you can visit the following link:

Configuring /etc/login.defs

The login program currently performs many functions which Linux-PAM modules should now handle. The following sed command will comment out the appropriate lines in /etc/login.defs, and stop login from performing these functions (a backup file named /etc/login.defs.orig is also created to preserve the original file's contents). Issue the following commands as the root user:

install -v -m644 /etc/login.defs /etc/login.defs.orig &&
for FUNCTION in FAIL_DELAY               \
                FAILLOG_ENAB             \
                LASTLOG_ENAB             \
                MAIL_CHECK_ENAB          \
                OBSCURE_CHECKS_ENAB      \
                PORTTIME_CHECKS_ENAB     \
                QUOTAS_ENAB              \
                CONSOLE MOTD_FILE        \
                FTMP_FILE NOLOGINS_FILE  \
                ENV_HZ PASS_MIN_LEN      \
                SU_WHEEL_ONLY            \
                CRACKLIB_DICTPATH        \
                PASS_CHANGE_TRIES        \
                PASS_ALWAYS_WARN         \
                CHFN_AUTH ENCRYPT_METHOD \
                ENVIRON_FILE
do
    sed -i "s/^${FUNCTION}/# &/" /etc/login.defs
done
Configuring the /etc/pam.d/ Files

As mentioned previously in the Linux-PAM instructions, Linux-PAM has two supported methods for configuration. The commands below assume that you've chosen to use a directory based configuration, where each program has its own configuration file. You can optionally use a single /etc/pam.conf configuration file by using the text from the files below, and supplying the program name as an additional first field for each line.

As the root user, create the following Linux-PAM configuration files in the /etc/pam.d/ directory (or add the contents to the /etc/pam.conf file) using the following commands:

'login'
cat > /etc/pam.d/login << "EOF"
# Begin /etc/pam.d/login

# Set failure delay before next prompt to 3 seconds
auth      optional    pam_faildelay.so  delay=3000000

# Check to make sure that the user is allowed to login
auth      requisite   pam_nologin.so

# Check to make sure that root is allowed to login
# Disabled by default. You will need to create /etc/securetty
# file for this module to function. See man 5 securetty.
#auth      required    pam_securetty.so

# Additional group memberships - disabled by default
#auth      optional    pam_group.so

# include system auth settings
auth      include     system-auth

# check access for the user
account   required    pam_access.so

# include system account settings
account   include     system-account

# Set default environment variables for the user
session   required    pam_env.so

# Set resource limits for the user
session   required    pam_limits.so

# Display date of last login - Disabled by default
#session   optional    pam_lastlog.so

# Display the message of the day - Disabled by default
#session   optional    pam_motd.so

# Check user's mail - Disabled by default
#session   optional    pam_mail.so      standard quiet

# include system session and password settings
session   include     system-session
password  include     system-password

# End /etc/pam.d/login
EOF
'passwd'
cat > /etc/pam.d/passwd << "EOF"
# Begin /etc/pam.d/passwd

password  include     system-password

# End /etc/pam.d/passwd
EOF
'su'
cat > /etc/pam.d/su << "EOF"
# Begin /etc/pam.d/su

# always allow root
auth      sufficient  pam_rootok.so

# Allow users in the wheel group to execute su without a password
# disabled by default
#auth      sufficient  pam_wheel.so trust use_uid

# include system auth settings
auth      include     system-auth

# limit su to users in the wheel group
# disabled by default
#auth      required    pam_wheel.so use_uid

# include system account settings
account   include     system-account

# Set default environment variables for the service user
session   required    pam_env.so

# include system session settings
session   include     system-session

# End /etc/pam.d/su
EOF
'chpasswd' and 'newusers'
cat > /etc/pam.d/chpasswd << "EOF"
# Begin /etc/pam.d/chpasswd

# always allow root
auth      sufficient  pam_rootok.so

# include system auth and account settings
auth      include     system-auth
account   include     system-account
password  include     system-password

# End /etc/pam.d/chpasswd
EOF

sed -e s/chpasswd/newusers/ /etc/pam.d/chpasswd >/etc/pam.d/newusers
'chage'
cat > /etc/pam.d/chage << "EOF"
# Begin /etc/pam.d/chage

# always allow root
auth      sufficient  pam_rootok.so

# include system auth and account settings
auth      include     system-auth
account   include     system-account

# End /etc/pam.d/chage
EOF
Other shadow utilities
for PROGRAM in chfn chgpasswd chsh groupadd groupdel \
               groupmems groupmod useradd userdel usermod
do
    install -v -m644 /etc/pam.d/chage /etc/pam.d/${PROGRAM}
    sed -i "s/chage/$PROGRAM/" /etc/pam.d/${PROGRAM}
done

Warning

At this point, you should do a simple test to see if Shadow is working as expected. Open another terminal and log in as root, and then run login and login as another user. If you do not see any errors, then all is well and you should proceed with the rest of the configuration. If you did receive errors, stop now and double check the above configuration files manually. Any error is the sign of an error in the above procedure. You can also run the test suite from the Linux-PAM package to assist you in determining the problem. If you cannot find and fix the error, you should recompile Shadow adding the --without-libpam switch to the configure command in the above instructions (also move the /etc/login.defs.orig backup file to /etc/login.defs). If you fail to do this and the errors remain, you will be unable to log into your system.

Configuring Login Access

Instead of using the /etc/login.access file for controlling access to the system, Linux-PAM uses the pam_access.so module along with the /etc/security/access.conf file. Rename the /etc/login.access file using the following command:

[ -f /etc/login.access ] && mv -v /etc/login.access{,.NOUSE}
Configuring Resource Limits

Instead of using the /etc/limits file for limiting usage of system resources, Linux-PAM uses the pam_limits.so module along with the /etc/security/limits.conf file. Rename the /etc/limits file using the following command:

[ -f /etc/limits ] && mv -v /etc/limits{,.NOUSE}

Caution

Be sure to test the login capabilities of the system before logging out. Errors in the configuration can cause a permanent lockout requiring a boot from an external source to correct the problem.

Contents

A list of the installed files, along with their short descriptions can be found at ../../../../lfs/view/development/chapter08/shadow.html#contents-shadow.

ssh-askpass-9.0p1

Introduction to ssh-askpass

The ssh-askpass is a generic executable name for many packages, with similar names, that provide a interactive X service to grab password for packages requiring administrative privileges to be run. It prompts the user with a window box where the necessary password can be inserted. Here, we choose Damien Miller's package distributed in the OpenSSH tarball.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

ssh-askpass Dependencies

Required

GTK+-2.24.33, Sudo-1.9.10 (runtime), Xorg Libraries, and a graphical environment (runtime)

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/ssh-askpass

Installation of ssh-askpass

Install ssh-askpass by running the following commands:

cd contrib &&
make gnome-ssh-askpass2

Now, as the root user:

install -v -d -m755                    /usr/libexec/openssh/contrib  &&
install -v -m755    gnome-ssh-askpass2 /usr/libexec/openssh/contrib  &&
ln -sv -f contrib/gnome-ssh-askpass2   /usr/libexec/openssh/ssh-askpass

The use of /usr/libexec/openssh/contrib and a symlink is justified by the eventual necessity of a different program for that service.

Configuring ssh-askpass

Configuration Information

As the root user, configure Sudo-1.9.10 to use ssh-askpass:

cat >> /etc/sudo.conf << "EOF" &&
# Path to askpass helper program
Path askpass /usr/libexec/openssh/ssh-askpass
EOF
chmod -v 0644 /etc/sudo.conf

If a given graphical <application> requires administrative privileges, use sudo -A <application> from an x-terminal, from a Window Manager menu and/or replace "Exec=<application> ..." by "Exec=sudo -A <application> ..." in the <application>.desktop file.

Contents

Installed Programs: None
Installed Library: None
Installed Directory: /usr/libexec/openssh/contrib

stunnel-5.63

Introduction to stunnel

The stunnel package contains a program that allows you to encrypt arbitrary TCP connections inside SSL (Secure Sockets Layer) so you can easily communicate with clients over secure channels. stunnel can also be used to tunnel PPP over network sockets without changes to the server package source code.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

stunnel Dependencies

Optional

libnsl-2.0.0, netcat (required for tests), tcpwrappers, and TOR

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/stunnel

Installation of stunnel

The stunnel daemon will be run in a chroot jail by an unprivileged user. Create the new user and group using the following commands as the root user:

groupadd -g 51 stunnel &&
useradd -c "stunnel Daemon" -d /var/lib/stunnel \
        -g stunnel -s /bin/false -u 51 stunnel

Note

A signed SSL Certificate and a Private Key is necessary to run the stunnel daemon. After the package is installed, there are instructions to generate them. However, if you own or have already created a signed SSL Certificate you wish to use, copy it to /etc/stunnel/stunnel.pem before starting the build (ensure only root has read and write access). The .pem file must be formatted as shown below:

-----BEGIN PRIVATE KEY-----
<many encrypted lines of private key>
-----END PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
<many encrypted lines of certificate>
-----END CERTIFICATE-----
-----BEGIN DH PARAMETERS-----
<encrypted lines of dh parms>
-----END DH PARAMETERS-----

Install stunnel by running the following commands:

./configure --prefix=/usr        \
            --sysconfdir=/etc    \
            --localstatedir=/var \
            --disable-systemd    &&
make

If you have installed the optional netcat application, the regression tests can be run with make check.

Now, as the root user:

make docdir=/usr/share/doc/stunnel-5.63 install

If you do not already have a signed SSL Certificate and Private Key, create the stunnel.pem file in the /etc/stunnel directory using the command below. You will be prompted to enter the necessary information. Ensure you reply to the

Common Name (FQDN of your server) [localhost]:

prompt with the name or IP address you will be using to access the service(s).

To generate a certificate, as the root user, issue:

make cert

Command Explanations

--disable-systemd: This switch disables systemd socket activation support which is not available in BLFS.

make docdir=... install: This command installs the package and changes the documentation installation directory to standard naming conventions.

Configuring stunnel

Config Files

/etc/stunnel/stunnel.conf

Configuration Information

As the root user, create the directory used for the .pid file created when the stunnel daemon starts:

install -v -m750 -o stunnel -g stunnel -d /var/lib/stunnel/run &&
chown stunnel:stunnel /var/lib/stunnel

Next, create a basic /etc/stunnel/stunnel.conf configuration file using the following commands as the root user:

cat > /etc/stunnel/stunnel.conf << "EOF"
; File: /etc/stunnel/stunnel.conf

; Note: The pid and output locations are relative to the chroot location.

pid    = /run/stunnel.pid
chroot = /var/lib/stunnel
client = no
setuid = stunnel
setgid = stunnel
cert   = /etc/stunnel/stunnel.pem

;debug = 7
;output = stunnel.log

;[https]
;accept  = 443
;connect = 80
;; "TIMEOUTclose = 0" is a workaround for a design flaw in Microsoft SSL
;; Microsoft implementations do not use SSL close-notify alert and thus
;; they are vulnerable to truncation attacks
;TIMEOUTclose = 0

EOF

Finally, add the service(s) you wish to encrypt to the configuration file. The format is as follows:

[<service>]
accept  = <hostname:portnumber>
connect = <hostname:portnumber>

For a full explanation of the commands and syntax used in the configuration file, issue man stunnel.

Boot Script

To automatically start the stunnel daemon when the system is booted, install the /etc/rc.d/init.d/stunnel bootscript from the blfs-bootscripts-20210826 package.

make install-stunnel

Contents

Installed Programs: stunnel and stunnel3
Installed Library: libstunnel.so
Installed Directories: /{etc,lib,var/lib}/stunnel and /usr/share/doc/stunnel-5.63

Short Descriptions

stunnel

is a program designed to work as an SSL encryption wrapper between remote clients and local or remote servers

stunnel3

is a Perl wrapper script to use stunnel 3.x syntax with stunnel 4.05 or later

libstunnel.so

contains the API functions required by stunnel

Sudo-1.9.10

Introduction to Sudo

The Sudo package allows a system administrator to give certain users (or groups of users) the ability to run some (or all) commands as root or another user while logging the commands and arguments.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Sudo Dependencies

Optional

Linux-PAM-1.5.2, MIT Kerberos V5-1.19.3, OpenLDAP-2.6.2, MTA (that provides a sendmail command), AFS, FWTK, and Opie

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/sudo

Installation of Sudo

Install Sudo by running the following commands:

./configure --prefix=/usr              \
            --libexecdir=/usr/lib      \
            --with-secure-path         \
            --with-all-insults         \
            --with-env-editor          \
            --docdir=/usr/share/doc/sudo-1.9.10 \
            --with-passprompt="[sudo] password for %p: " &&
make

To test the results, issue: env LC_ALL=C make check 2>&1 | tee make-check.log. Check the results with grep failed make-check.log.

Now, as the root user:

make install &&
ln -sfv libsudo_util.so.0.0.0 /usr/lib/sudo/libsudo_util.so.0

Command Explanations

--libexecdir=/usr/lib: This switch controls where private programs are installed. Everything in that directory is a library, so they belong under /usr/lib instead of /usr/libexec.

--with-secure-path: This switch transparently adds /sbin and /usr/sbin directories to the PATH environment variable.

--with-all-insults: This switch includes all the sudo insult sets.

--with-env-editor: This switch enables use of the environment variable EDITOR for visudo.

--with-passprompt: This switch sets the password prompt. The %p will be expanded to the name of the user whose password is being requested.

--without-pam: This switch avoids building Linux-PAM support when Linux-PAM is installed on the system.

Note

There are many options to sudo's configure command. Check the configure --help output for a complete list.

ln -sfv libsudo_util...: Works around a bug in the installation process, which links to the previously installed version (if there is one) instead of the new one.

Configuring Sudo

Config File

/etc/sudoers

Configuration Information

The sudoers file can be quite complicated. It is composed of two types of entries: aliases (basically variables) and user specifications (which specify who may run what). The installation installs a default configuration that has no privileges installed for any user.

A couple of common configuration changes are to set the path for the super user and to allow members of the wheel group to execute all commands after providing their own credientials. Use the following commands to create the /etc/sudoers.d/00-sudo configuration file as the root user:

cat > /etc/sudoers.d/00-sudo << "EOF"
Defaults secure_path="/usr/sbin:/usr/bin"
%wheel ALL=(ALL) ALL
EOF

Note

In very simple installations where there is only one user, it may be easier to just edit the /etc/sudoers file directly. In that case, the secure_path entry may not be needed and using sudo -E ... can import the non-privileged user's full environment into the privileged session.

The files in the /etc/sudoers.d directory are parsed in sorted lexical order. Be careful that entries in an added file do not overwrite previous entries.

For details, see man sudoers.

Note

The Sudo developers highly recommend using the visudo program to edit the sudoers file. This will provide basic sanity checking like syntax parsing and file permission to avoid some possible mistakes that could lead to a vulnerable configuration.

If PAM is installed on the system, Sudo is built with PAM support. In that case, issue the following command as the root user to create the PAM configuration file:

cat > /etc/pam.d/sudo << "EOF"
# Begin /etc/pam.d/sudo

# include the default auth settings
auth      include     system-auth

# include the default account settings
account   include     system-account

# Set default environment variables for the service user
session   required    pam_env.so

# include system session defaults
session   include     system-session

# End /etc/pam.d/sudo
EOF
chmod 644 /etc/pam.d/sudo

Contents

Installed Programs: cvtsudoers, sudo, sudo_logsrvd, sudo_sendlog, sudoedit (symlink), sudoreplay, and visudo
Installed Libraries: audit_json.so, group_file.so, libsudo_util.so, sample_approval.so, sudoers.so, sudo_noexec.so, and system_group.so
Installed Directories: /etc/sudoers.d, /usr/lib/sudo, /usr/share/doc/sudo-1.9.10, and /var/lib/sudo

Short Descriptions

cvtsudoers

converts between sudoers file formats

sudo

executes a command as another user as permitted by the /etc/sudoers configuration file

sudo_logsrvd

is a sudo event and I/O log server

sudo_sendlog

sends sudo I/O logs to the log server

sudoedit

is a symlink to sudo that implies the -e option to invoke an editor as another user

sudoreplay

is used to play back or list the output logs created by sudo

visudo

allows for safer editing of the sudoers file

Tripwire-2.4.3.7

Introduction to Tripwire

The Tripwire package contains programs used to verify the integrity of the files on a given system.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information

Tripwire Dependencies

Optional

An MTA

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/tripwire

Installation of Tripwire

Compile Tripwire by running the following commands:

sed -e '/^CLOBBER/s/false/true/'         \
    -e 's|TWDB="${prefix}|TWDB="/var|'   \
    -e '/TWMAN/ s|${prefix}|/usr/share|' \
    -e '/TWDOCS/s|${prefix}/doc/tripwire|/usr/share/doc/tripwire-2.4.3.7|' \
    -i installer/install.cfg                               &&

find . -name Makefile.am | xargs                           \
    sed -i 's/^[[:alpha:]_]*_HEADERS.*=/noinst_HEADERS =/' &&

sed '/dist/d' -i man/man?/Makefile.am                      &&
autoreconf -fi                                             &&

./configure --prefix=/usr --sysconfdir=/etc/tripwire       &&
make CPPFLAGS=-std=c++11

Note

The default configuration is to use a local MTA. If you don't have an MTA installed and have no wish to install one, modify install/install.cfg to use an SMTP server instead. Otherwise the install will fail.

This package does not come with a test suite.

Now, as the root user:

make install &&
cp -v policy/*.txt /usr/share/doc/tripwire-2.4.3.7

Note

During make install, several questions are asked, including passwords. If you want to make a script, you have to apply a sed before running make install:

sed -i -e 's@installer/install.sh@& -n -s <site-password> -l <local-password>@' Makefile

Of course, you should do this with dummy passwords and change them later.

Another issue when scripting is that the installer exits when the standard input is not a terminal. You may disable this behavior with the following sed:

sed '/-t 0/,+3d' -i installer/install.sh

Command Explanations

sed ... installer/install.cfg: This command tells the package to install the program database and reports in /var/lib/tripwire and sets the proper location for man pages and documentation.

find ..., sed ..., and autoreconf -fi: The build system is unusable as is, and has to be modified for the build to succeed.

CPPFLAGS=-std=c++11: Setting the C++ preprocessor flags to version 11 is necessary to prevent a conflict with the default version which is c++17 in recent version of gcc.

make install: This command creates the Tripwire security keys as well as installing the binaries. There are two keys: a site key and a local key which are stored in /etc/tripwire/.

cp -v policy/*.txt /usr/doc/tripwire-2.4.3.7: This command installs the tripwire sample policy files with the other tripwire documentation.i

Configuring Tripwire

Config Files

/etc/tripwire/*

Configuration Information

Tripwire uses a policy file to determine which files are integrity checked. The default policy file (/etc/tripwire/twpol.txt) is for a default installation and will need to be updated for your system.

Policy files should be tailored to each individual distribution and/or installation. Some example policy files can be found in /usr/share/doc/tripwire/.

If desired, copy the policy file you'd like to try into /etc/tripwire/ instead of using the default policy file, twpol.txt. It is, however, recommended that you edit your policy file. Get ideas from the examples above and read /usr/share/doc/tripwire/policyguide.txt for additional information. twpol.txt is a good policy file for learning about Tripwire as it will note any changes to the file system and can even be used as an annoying way of keeping track of changes for uninstallation of software.

After your policy file has been edited to your satisfaction you may begin the configuration steps (perform as the root) user:

twadmin --create-polfile --site-keyfile /etc/tripwire/site.key \
    /etc/tripwire/twpol.txt &&
tripwire --init

Depending on your system and the contents of the policy file, the initialization phase above can take a relatively long time.

Usage Information

Tripwire will identify file changes in the critical system files specified in the policy file. Using Tripwire while making frequent changes to these directories will flag all these changes. It is most useful after a system has reached a configuration that the user considers stable.

To use Tripwire after creating a policy file to run a report, use the following command:

tripwire --check > /etc/tripwire/report.txt

View the output to check the integrity of your files. An automatic integrity report can be produced by using a cron facility to schedule the runs.

Reports are stored in binary and, if desired, encrypted. View reports, as the root user, with:

twprint --print-report -r /var/lib/tripwire/report/<report-name.twr>

After you run an integrity check, you should examine the report (or email) and then modify the Tripwire database to reflect the changed files on your system. This is so that Tripwire will not continually notify you hat files you intentionally changed are a security violation. To do this you must first ls -l /var/lib/tripwire/report/ and note the name of the newest file which starts with your system name as presented by the command uname -n and ends in .twr. These files were created during report creation and the most current one is needed to update the Tripwire database of your system. As the root user, type in the following command making the appropriate report name:

tripwire --update --twrfile /var/lib/tripwire/report/<report-name.twr>

You will be placed into Vim with a copy of the report in front of you. If all the changes were good, then just type :wq and after entering your local key, the database will be updated. If there are files which you still want to be warned about, remove the 'x' before the filename in the report and type :wq.

Changing the Policy File

If you are unhappy with your policy file and would like to modify it or use a new one, modify the policy file and then execute the following commands as the root user:

twadmin --create-polfile /etc/tripwire/twpol.txt &&
tripwire --init

Contents

Installed Programs: siggen, tripwire, twadmin, and twprint
Installed Libraries: None
Installed Directories: /etc/tripwire, /var/lib/tripwire, and /usr/share/doc/tripwire-2.4.3.7

Short Descriptions

siggen

is a signature gathering utility that displays the hash function values for the specified files

tripwire

is the main file integrity checking program

twadmin

administrative and utility tool used to perform certain administrative functions related to Tripwire files and configuration options

twprint

prints Tripwire database and report files in clear text format

volume_key-0.3.12

Introduction to volume_key

The volume_key package provides a library for manipulating storage volume encryption keys and storing them separately from volumes to handle forgotten passphrases.

Note

Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

Package Information