Debian's policy regarding security updates

From: Robert Glueck (rglk_at_web.de)
Date: 05/03/05


Date: Tue, 03 May 2005 17:45:29 -0400

I can't quite figure out the policy of Debian with regard to security
updates for their OS. From what I understand, it is as follows. Please
correct me if I'm wrong.

When a security vulnerability is discovered in a Linux package that's
part of the Debian distribution, Debian will attempt to prepare a fix
for it, first for stable (for all supported architectures) and perhaps
later then for unstable, and announce the fixes in a DSA. If they
managed to prepare a fix for unstable, it will be posted as such and
then after two days migrate automatically into the testing distro,
"after all dependencies have been fulfilled" (?).

For example, all of the 98 vulnerabilities that Debian issued DSA's for
so far in 2005 have been fixed for stable, and the great majority have
also been fixed for unstable. By now, all packages in the latter group
would have migrated into testing. Hence, I assume that the current
versions of all packages in the latter group in the testing distro have
received the security fix. For the rest, i.e. a small fraction of the
98 packages, the DSA states that "for the unstable distribution (sid)
these problems will be fixed soon."

The situation is thus fairly clear for stable: a vulnerability is
discovered, a fix is prepared, new deb packages are made for all
supported architectures, they are tested to make sure they don't break
any dependencies, and if everything is fine, they are released to the
public.

For unstable and testing, the situation is less clear. If the Debian
developers have time, they will prepare a fix for the most recent
version of the affected package, which would be in unstable, release it
(as source only?), and after a short quarantine it would become part of
the testing distro. Are these updated packages in the testing distro
then tested with regard to breaking dependencies? Are they available as
deb packages, e.g. for the intel 86 architecture?

With regard to the packages about which the DSA said that "for the
unstable distribution (sid) these problems will be fixed soon", does
that mean that Debian still hasn't fixed them for unstable (and
testing)? Or did they fix them and they are now in the testing distro
but Debian simply failed to update the advisory about this fact?

If this newsgroup isn't quite the right place to post this query, which
Debian newsgroup, forum or mailing list would be the appropriate place?

Robert

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Pertinent sections of the Debian Security FAQ:

Q: How is security handled in Debian?

A: Once the security team receives a notification of an incident, one or
more members review it and consider its impact on the stable release of
Debian (i.e. if it's vulnerable or not). If our system is vulnerable, we
work on a fix for the problem. The package maintainer is contacted as
well, if they didn't contact the security team already. Finally, the fix
is tested and new packages are prepared, which are then compiled on all
stable architectures and uploaded afterwards. After all of that is done,
an advisory is published.

Q: How is security handled for testing and unstable?

A: The short answer is: it's not. Testing and unstable are rapidly
moving targets and the security team does not have the resources needed
to properly support those. If you want to have a secure (and stable)
server you are strongly encouraged to stay with stable. However, the
security secretaries will try to fix problems in testing and unstable
after they are fixed in the stable release.

Q: How does testing get security updates?

A: Security updates will migrate into the testing distribution via
unstable. They are usually uploaded with their priority set to high,
which will reduce the quarantine time to two days. After this period,
the packages will migrate into testing automatically, given that they
are built for all architectures and their dependencies are fulfilled in
testing.



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