RHSA-2012:1430 - Security Advisory

Topic

Updated kernel packages that fix one security issue and three bugs are now
available for Red Hat Enterprise Linux 6.1 Extended Update Support.

The Red Hat Security Response Team has rated this update as having
important security impact. A Common Vulnerability Scoring System (CVSS)
base score, which gives a detailed severity rating, is available from the
CVE link in the References section.

Description

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

This update fixes the following security issue:

• A flaw was found in the way socket buffers (skb) requiring TSO (TCP

segment offloading) were handled by the sfc driver. If the skb did not fit
within the minimum-size of the transmission queue, the network card could
repeatedly reset itself. A remote attacker could use this flaw to cause a
denial of service. (CVE-2012-3412, Important)

Red Hat would like to thank Ben Hutchings of Solarflare (tm) for reporting
this issue.

This update also fixes the following bugs:

• In the hpet_next_event() function, an interrupt could have occurred

between the read and write of the HPET (High Precision Event Timer) and the
value of HPET_COUNTER was then beyond that being written to the comparator
(HPET_Tn_CMP). Consequently, the timers were overdue for up to several
minutes. Now, a comparison is performed between the value of the counter
and the comparator in the HPET code. If the counter is beyond the
comparator, the "-ETIME" error code is returned, which fixes this bug.
(BZ#855280)

• Traffic to the NFS server could trigger a kernel oops in the

svc_tcp_clear_pages() function. The source code has been modified, and the
kernel oops no longer occurs in this scenario. (BZ#856104)

• A kernel oops occurred in the nf_nat code when a bogus pointer was

dereferenced in the nf_conn_nat structure. Consequently, if Source Network
Address Translation (SNAT) was performed, incorrect information could be
received by other CTS (Clear to Send) signals. A conntrack entry is now
placed in the source hash after SNAT has been completed, which prevents the
described problems. (BZ#865714)

Users should upgrade to these updated packages, which contain backported
patches to resolve these issues. 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

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.1 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 ppc64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 x86_64

Fixes

• BZ - 844714 - CVE-2012-3412 kernel: sfc: potential remote denial of service through TCP MSS option

CVEs

• CVE-2012-3412

References

• https://access.redhat.com/security/updates/classification/#important