RHSA-2012:0350 - Security Advisory

Topic

Updated kernel packages that fix various security issues and several bugs
are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
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 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 the Linux kernel's XFS file

system implementation handled links with overly long path names. A local,
unprivileged user could use this flaw to cause a denial of service or
escalate their privileges by mounting a specially-crafted disk.
(CVE-2011-4077, Moderate)

• Flaws in ghash_update() and ghash_final() could allow a local,

unprivileged user to cause a denial of service. (CVE-2011-4081, Moderate)

• A flaw was found in the Linux kernel's Journaling Block Device (JBD). A

local, unprivileged user could use this flaw to crash the system by
mounting a specially-crafted ext3 or ext4 disk. (CVE-2011-4132, Moderate)

• It was found that the kvm_vm_ioctl_assign_device() function in the KVM

(Kernel-based Virtual Machine) subsystem of a Linux kernel did not check if
the user requesting device assignment was privileged or not. A local,
unprivileged user on the host could assign unused PCI devices, or even
devices that were in use and whose resources were not properly claimed by
the respective drivers, which could result in the host crashing.
(CVE-2011-4347, Moderate)

• Two flaws were found in the way the Linux kernel's __sys_sendmsg()

function, when invoked via the sendmmsg() system call, accessed user-space
memory. A local, unprivileged user could use these flaws to cause a denial
of service. (CVE-2011-4594, Moderate)

• The RHSA-2011:1530 kernel update introduced an integer overflow flaw in

the Linux kernel. On PowerPC systems, a local, unprivileged user could use
this flaw to cause a denial of service. (CVE-2011-4611, Moderate)

• A flaw was found in the way the KVM subsystem of a Linux kernel handled

PIT (Programmable Interval Timer) IRQs (interrupt requests) when there was
no virtual interrupt controller set up. A local, unprivileged user on the
host could force this situation to occur, resulting in the host crashing.
(CVE-2011-4622, Moderate)

• A flaw was found in the way the Linux kernel's XFS file system

implementation handled on-disk Access Control Lists (ACLs). A local,
unprivileged user could use this flaw to cause a denial of service or
escalate their privileges by mounting a specially-crafted disk.
(CVE-2012-0038, Moderate)

• A flaw was found in the way the Linux kernel's KVM hypervisor

implementation emulated the syscall instruction for 32-bit guests. An
unprivileged guest user could trigger this flaw to crash the guest.
(CVE-2012-0045, Moderate)

• A divide-by-zero flaw was found in the Linux kernel's igmp_heard_query()

function. An attacker able to send certain IGMP (Internet Group Management
Protocol) packets to a target system could use this flaw to cause a denial
of service. (CVE-2012-0207, Moderate)

Red Hat would like to thank Nick Bowler for reporting CVE-2011-4081; Sasha
Levin for reporting CVE-2011-4347; Tetsuo Handa for reporting
CVE-2011-4594; Maynard Johnson for reporting CVE-2011-4611; Wang Xi for
reporting CVE-2012-0038; Stephan Bärwolf for reporting CVE-2012-0045; and
Simon McVittie for reporting CVE-2012-0207. Upstream acknowledges Mathieu
Desnoyers as the original reporter of CVE-2011-4594.

This update also fixes several 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 contain backported
patches to correct these issues, and fix the bugs noted in the 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

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.2 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.2 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 i386
• Red Hat Storage 2.0 x86_64
• Red Hat Gluster Storage Server for On-premise 2.0 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.0 x86_64
• Red Hat Enterprise Linux Server - AUS 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 749156 - CVE-2011-4077 kernel: xfs: potential buffer overflow in xfs_readlink()
• BZ - 749475 - CVE-2011-4081 kernel: crypto: ghash: null pointer deref if no key is set
• BZ - 753341 - CVE-2011-4132 kernel: jbd/jbd2: invalid value of first log block leads to oops
• BZ - 756084 - CVE-2011-4347 kernel: kvm: device assignment DoS
• BZ - 761646 - CVE-2011-4594 kernel: send(m)msg: user pointer dereferences
• BZ - 767914 - CVE-2011-4611 kernel: perf, powerpc: Handle events that raise an exception without overflowing
• BZ - 769721 - CVE-2011-4622 kernel: kvm: pit timer with no irqchip crashes the system
• BZ - 772867 - CVE-2012-0207 kernel: igmp: Avoid zero delay when receiving odd mixture of IGMP queries
• BZ - 773280 - CVE-2012-0038 kernel: xfs heap overflow
• BZ - 773370 - CVE-2012-0045 kernel: kvm: syscall instruction induced guest panic
• BZ - 789058 - cifs: i/o error on copying file > 102336 bytes [rhel-6.2.z]

CVEs

• CVE-2011-4132
• CVE-2011-4077
• CVE-2011-4081
• CVE-2011-4622
• CVE-2012-0207
• CVE-2011-4347
• CVE-2012-0038
• CVE-2011-4594
• CVE-2012-0045
• CVE-2011-4611

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://rhn.redhat.com/errata/RHSA-2011-1530.html
• https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.2_Technical_Notes/kernel.html#RHSA-2012-0350