7.8 - RHSA-2012:0350

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - noarch, x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, x86_64

3. 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.

4. 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.

5. Bugs fixed (http://bugzilla.redhat.com/):

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