** Description changed:
- Hello,
+ [Impact]
+ ========
- there seems to be a bug in libpam-mount in version 2.16-10 used in
- Ubuntu 20.04.
+ Mount a cifs volume with a regex condition results in a segfault.
- I want to mount a cifs volume with a regex condition.
+
+ [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}.*$</user>
- </and>
+ <and>
+ <user regex="yes">^[a-z]{3}.*$</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.
+
+
+ [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.
-
- Best regards
- Daniel
** Description changed:
[Impact]
========
- Mount a cifs volume with a regex condition results in a segfault.
-
+ 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.
-
[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.
** Changed in: libpam-mount (Ubuntu Focal)
Assignee: (unassigned) => Utkarsh Gupta (utkarsh)
** No longer affects: pcre2 (Ubuntu)
** No longer affects: pcre2 (Ubuntu Focal)
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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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