Scientific Linux Security Update : sssd on SL5.x i386/x86_64

This script is Copyright (C) 2013 Tenable Network Security, Inc.


Synopsis :

The remote Scientific Linux host is missing one or more security
updates.

Description :

A race condition was found in the way SSSD copied and removed user
home directories. A local attacker who is able to write into the home
directory of a different user who is being removed could use this flaw
to perform symbolic link attacks, possibly allowing them to modify and
delete arbitrary files with the privileges of the root user.
(CVE-2013-0219)

This update also fixes the following bugs :

- After a paging control was used, memory in the sssd_be
process was never freed which led to the growth of the
sssd_be process memory usage over time. To fix this bug,
the paging control was deallocated after use, and thus
the memory usage of the sssd_be process no longer grows.

- If the sssd_be process was terminated and recreated
while there were authentication requests pending, the
sssd_pam process did not recover correctly and did not
reconnect to the new sssd_be process. Consequently, the
sssd_pam process was seemingly blocked and did not
accept any new authentication requests. The sssd_pam
process has been fixes so that it reconnects to the new
instance of the sssd_be process after the original one
terminated unexpectedly. Even after a crash and
reconnect, the sssd_pam process now accepts new
authentication requests.

- When the sssd_be process hung for a while, it was
terminated and a new instance was created. If the old
instance did not respond to the TERM signal and
continued running, SSSD terminated unexpectedly. As a
consequence, the user could not log in. SSSD now keeps
track of sssd_be subprocesses more effectively, making
the restarts of sssd_be more reliable in such scenarios.
Users can now log in whenever the sssd_be is restarted
and becomes unresponsive.

- In case the processing of an LDAP request took longer
than the client timeout upon completing the request (60
seconds by default), the PAM client could have accessed
memory that was previously freed due to the client
timeout being reached. As a result, the sssd_pam process
terminated unexpectedly with a segmentation fault. SSSD
now ignores an LDAP request result when it detects that
the set timeout of this request has been reached. The
sssd_pam process no longer crashes in the aforementioned
scenario.

- When there was a heavy load of users and groups to be
saved in cache, SSSD experienced a timeout.
Consequently, NSS did not start the backup process
properly and it was impossible to log in. A patch has
been provided to fix this bug. The SSSD daemon now
remains responsive and the login continues as expected.

- SSSD kept the file descriptors to the log files open.
Consequently, on occasions like moving the actual log
file and restarting the back end, SSSD still kept the
file descriptors open. SSSD now closes the file
descriptor after the child process execution
after a
successful back end start, the file descriptor to log
files is closed.

- While performing access control in the Identity
Management back end, SSSD erroneously downloaded the
'member' attribute from the server and then attempted to
use it in the cache verbatim. Consequently, the cache
attempted to use the 'member' attribute values as if
they were pointing to the local cache which was CPU
intensive. The member attribute when processing host
groups is no longer downloaded and processed. Moreover,
the login process is reasonably fast even with large
host groups.

See also :

http://www.nessus.org/u?2036f6ae

Solution :

Update the affected packages.

Risk factor :

Low / CVSS Base Score : 3.7
(CVSS2#AV:L/AC:H/Au:N/C:P/I:P/A:P)

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 70391 ()

Bugtraq ID:

CVE ID: CVE-2013-0219