RHSA-2013:0566 - Security Advisory

Topic

Updated kernel-rt packages that fix several security issues and multiple
bugs are now available for Red Hat Enterprise MRG 2.3.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

Description

The kernel-rt packages contain the Linux kernel, the core of any Linux
operating system.

This update fixes the following security issues:

• A buffer overflow flaw was found in the way UTF-8 characters were

converted to UTF-16 in the utf8s_to_utf16s() function of the Linux kernel's
FAT file system implementation. A local user able to mount a FAT file
system with the "utf8=1" option could use this flaw to crash the system or,
potentially, to escalate their privileges. (CVE-2013-1773, Important)

• It was found that the RHSA-2012:0333 update did not correctly fix the

CVE-2011-4131 issue. A malicious Network File System version 4 (NFSv4)
server could return a crafted reply to a GETACL request, causing a denial
of service on the client. (CVE-2012-2375, Moderate)

• A memory disclosure flaw was found in the way the load_script() function

in the binfmt_script binary format handler handled excessive recursions. A
local, unprivileged user could use this flaw to leak kernel stack memory to
user-space by executing specially-crafted scripts. (CVE-2012-4530, Low)

• A flaw was found in the way file permission checks for the "/dev/kmsg"

file were performed in restricted root environments (for example, when
using a capability-based security model). A local user able to write to
this file could cause a denial of service. (CVE-2013-1772, Low)

The CVE-2012-2375 issue was discovered by Jian Li of Red Hat.

This update also fixes multiple bugs. Documentation for these changes will
be available shortly from the Technical Notes document linked to in the
References section.

Users should upgrade to these updated packages, which upgrade the kernel-rt
kernel to version kernel-rt-3.6.11-rt28, correct these issues, and fix the
bugs noted in the Red Hat Enterprise MRG 2 Technical Notes. The system must
be rebooted for this update to take effect.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

Affected Products

• MRG Realtime 2 x86_64

Fixes

• BZ - 773017 - kernel-rt-{debug,trace}-debuginfo conflicts against kernel-debuginfo
• BZ - 822869 - CVE-2012-2375 kernel: incomplete fix for CVE-2011-4131
• BZ - 866596 - RFE: rebase to 3.4 or greater kernel [mrg2.3]
• BZ - 866600 - RFE: adding PTP kernel support as a Tech Preview [mrg2.3]
• BZ - 868285 - CVE-2012-4530 kernel: stack disclosure in binfmt_script load_script()
• BZ - 916075 - CVE-2013-1772 kernel: call_console_drivers() function log prefix stripping DoS
• BZ - 916115 - CVE-2013-1773 kernel: VFAT slab-based buffer overflow

CVEs

• CVE-2012-2375
• CVE-2012-4530
• CVE-2013-1773
• CVE-2013-1772

References

• https://access.redhat.com/security/updates/classification/#important
• https://rhn.redhat.com/errata/RHSA-2012-0333.html
• https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_MRG/2/html/Technical_Notes/RHSA-2013-0566.html