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debian testing with automatic security updates from unstable
APT::Default-Release "testing";
APT::Update::Pre-Invoke { "/usr/sbin/debsecan-apt-priority"; };

overview

WARNING: these commands can be very disruptive. review each of the files in this gist and on the filesystem which they will replace before executing the commands below.

when you run apt update, this script will be executed automatically. for each vulnerable package in testing which has been fixed in unstable, it will create a priority 990 pin for the unstable package.

background

from https://wiki.debian.org/DebianTesting:

It is a good idea to install security updates from unstable since they take extra time to reach testing and the security team only releases updates to unstable. If you have unstable in your apt sources but pinned lower than testing, you can automatically add temporary pinning for packages with security issues fixed in unstable using the output of debsecan.

prerequisites

the installation section assumes that you are running debian testing and have the unstable repositories enabled and pinned at a lower priority than staging. you can usually achieve this by running the following as root:

# curl -o /etc/apt/apt.conf.d/00default-release https://gist.githubusercontent.com/khimaros/21db936fa7885360f7bfe7f116b78daf/raw/698266fc043d6e906189b14e3428187ff0e7e7c8/00default-release
# curl -o /etc/apt/sources.list https://gist.githubusercontent.com/khimaros/21db936fa7885360f7bfe7f116b78daf/raw/698266fc043d6e906189b14e3428187ff0e7e7c8/sources.list
# apt update

installation

execute the following commands as root:

# apt install -y debsecan
# curl -o /usr/sbin/debsecan-apt-priority https://gist.githubusercontent.com/khimaros/21db936fa7885360f7bfe7f116b78daf/raw/698266fc043d6e906189b14e3428187ff0e7e7c8/debsecan-apt-priority
# curl -o /etc/apt/apt.conf.d/99debsecan https://gist.githubusercontent.com/khimaros/21db936fa7885360f7bfe7f116b78daf/raw/698266fc043d6e906189b14e3428187ff0e7e7c8/99debsecan
# chmod 755 /usr/sbin/debsecan-apt-priority
# ln -sf /var/lib/debsecan/apt_preferences /etc/apt/preferences.d/unstable-security-packages
# apt update

special cases

i recommend always running chromium and firefox from unstable:

# curl -o /etc/apt/preferences.d/unstable-packages https://gist.githubusercontent.com/khimaros/21db936fa7885360f7bfe7f116b78daf/raw/698266fc043d6e906189b14e3428187ff0e7e7c8/unstable-packages
# apt update && apt install -y chromium firefox

uninstallation

note: uninstalling will not downgrade packages to their testing versions. you will need to do this yourself or wait for the packages to catch up on their own (which should typically happen within a few weeks).

# rm -f /etc/apt/preferences.d/unstable-security-packages
# rm -f /etc/apt/apt.conf.d/99debsecan
# apt update
#!/bin/sh
# this program will add APT pinning for packages that are fixed in
# unstable and not testing
#
# see https://bugs.debian.org/725934
set -e
echo "running debsecan check for issues fixed in unstable..." >&2
rm -f /var/lib/debsecan/apt_preferences.disabled
cat > /var/lib/debsecan/apt_preferences.disabled <<EOF
# pin packages with security issues fixed in unstable
# generated automatically on $(date) by $0
EOF
for pkg in $(debsecan --suite=sid --only-fixed | cut -d\ -f2 | sort -u) ; do
suite=unstable
case "$pkg" in
*-dbgsym)
suite=unstable-debug
;;
esac
echo "adding pin to suite $suite for package $pkg" >&2
cat <<EOF >> /var/lib/debsecan/apt_preferences.disabled
Package: $pkg
Pin: release a=$suite
Pin-Priority: 990
EOF
done
chmod 644 /var/lib/debsecan/apt_preferences.disabled
mv --force /var/lib/debsecan/apt_preferences.disabled /var/lib/debsecan/apt_preferences
deb http://deb.debian.org/debian/ testing main non-free contrib
deb-src http://deb.debian.org/debian/ testing main non-free contrib
deb http://security.debian.org/debian-security testing-security main contrib non-free
deb-src http://security.debian.org/debian-security testing-security main contrib non-free
deb http://deb.debian.org/debian/ unstable main non-free contrib
deb-src http://deb.debian.org/debian/ unstable main non-free contrib
Package: chromium chromium-sandbox chromium-common
Pin: release a=unstable
Pin-Priority: 990
Package: firefox libnss3 libnss3:i386 libnss3-dev
Pin: release a=unstable
Pin-Priority: 990
@khimaros
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Author

khimaros commented Feb 22, 2022

@martin-braun -- this is needed because there is still a delay (sometimes as long as weeks) between fixes entering testing-security from the unstable repo.

@martin-braun
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martin-braun commented Feb 22, 2022

@khimaros Thanks for the quick reply, I already removed my comment, because I realized this by myself. However one more thing: https://gist.github.com/khimaros/21db936fa7885360f7bfe7f116b78daf#file-debsecan-apt-priority-L27

This looks wrong to me, shouldn't the first EOF stay behind like at https://gist.github.com/khimaros/21db936fa7885360f7bfe7f116b78daf#file-debsecan-apt-priority-L13 ?

In any case, I will try this on a clean Debian in combination with additional Sparky repositories, will see how it goes. Thanks for your work.

@khimaros
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khimaros commented Feb 22, 2022

@martin-braun -- either syntax works. actually, i should mention that this file actually came from another repository https://gitlab.com/anarcat/puppet/-/raw/b6bc3e3dc982abcc4100143abb6594404b1241ac/site-modules/profile/files/debsecan-apt-priority which was originally started collaboratively on this bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=725934

@martin-braun
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martin-braun commented Feb 23, 2022

@khimaros Great, thanks a lot! :) I'm using your solution and I hope it will work out in the long run. Thanks sharing!

@jmzumg
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jmzumg commented May 17, 2022

@khimaros

Thank you for the instructions and scripts here. There were extremely enlightening.

However I believe there is one small error in the instructions in README.md.

I believe the following line:

ln -sf /var/lib/debsecan/apt_priorities /etc/apt/preferences.d/unstable-security-packages

should actually read:

ln -sf /var/lib/debsecan/apt_preferences /etc/apt/preferences.d/unstable-security-packages

Otherwise the symbolic link points to a non-existent file. apt outputs the following error:

N: Ignoring `unstable-security-packages` in directory '/etc/apt/preferences.d/ as it is not a regular file

and the packages pinned by debsecan do not get upgraded.

I have tested using ln -sf /var/lib/debsecan/apt_preferences /etc/apt/preferences.d/unstable-security-packages instead and everything seems to work.

Thanks again for the instructions :)

@khimaros
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khimaros commented Jun 7, 2022

@jmzumg thank you, updated!

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