sshd in chroot has regression with glibc 2.34

[William Wilson]

A regression to sshd running in a chroot exists under the following conditions:

1) sshd was built with glibc 2.34
2) sshd is running with a kernel that does not define the close_range syscall (kernel <= 5.8)
3) /proc/self/fd does not exist in the chroot

The glibc 2.34 implementation of fallback_closefrom fails if /proc/self/fd is not present, which is a valid sshd use case.

[William Wilson (jawn-smith)]

I created upstream bugs to track this:

https://bugzilla.mindrot.org/show_bug.cgi?id=3349
https://sourceware.org/bugzilla/show_bug.cgi?id=28377

[William Wilson (jawn-smith)]

This patch moves the configuration option to the appropriate section of d/rules and adds a reference to this bug report.

[Steve Langasek (vorlon)]

uploaded.

[Launchpad Janitor (janitor)]

This bug was fixed in the package openssh - 1:8.4p1-6ubuntu2

---------------
openssh (1:8.4p1-6ubuntu2) impish; urgency=medium

  * Configure with ac_cv_func_closefrom=no to avoid an incompatibility
    with glibc 2.34's fallback_closefrom function (LP: #1944621)

 -- William 'jawn-smith' Wilson <email address hidden> Tue, 21 Sep 2021 22:08:39 +0000