** Description changed:
[Impact]
========
Mounting a cifs volume with a regex condition results in a segfault.
[Test Plan]
===========
$ lxc launch images:ubuntu/focal lp1891552-fix-segfault
$ lxc shell lp1891552-fix-segfault
# apt update && apt install cifs-utils libpam-mount
# adduser user
// add the following lines in /etc/security/pam_mount.conf.xml above the
"<mkmountpoint enable="1" remove="true" />" line.
<volume fstype="cifs" server="server.example.com" path="folder/%(USER)"
mountpoint="/home/%(USER)/SUBFOLDER_%(USER)"
options="domain=DOMAIN,dir_mode=0700,file_mode=0700">
<and>
<user regex="yes">^[a-z]{3}.*$</user>
</and>
</volume>
# su - user
// you'll get a segfault.
// with the patched version, it shouldn't segfault and everything
// should work fine, as intended.
[Where Problems Could Occur]
============================
With this problem known, if the user has found a workaround for mounting
a cifs volume using some extra configuration or so, then that could
break the same on upgrade, I believe. For example, having a workaround
way of inserting <volume> in /etc/security/pam_mount.conf.xml with
manipulation and some hacking could get this to work and then upgrade
could break the hack. But on a brighter side, they could get back to
using the "right" way of inserting a <volume> in the .conf.xml file.
+ [Other Info]
+
+ The autopkgtests of this package that we've added back in Bionic have
degraded since then and were regularly failing. We know the fixes and they were
already accepted by Debian. As usual with test fixes they do not
+ qualify for an upload/SRU on their own, but since we touch these packages
anyway we also include the test fixes which will help to add back some
coverage. Also OTOH the SRU would be blocked with unresolvable test issues
without doing so.
+
[Discussion(s)]
===============
At system start the system freezes completely. Then I retested during a
running session on the command line and I'm getting the error message
Segmentation fault
when I login to another user.
If I remove the 'regex="yes"' everything works.
If I remove the "and" condition everything works.
If I downgrade the libpam-mount package to version 2.16-3ubuntu0.1 of Ubuntu
18.04 everything works including using the regex condition. In Ubuntu 18.04
everything worked fine as well.
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https://bugs.launchpad.net/bugs/1891552
Title:
Segmentation Fault in libpcre2-8-0 when using regex in (cifs) volume
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