RHSA-2016:0450 - Security Advisory

Topic

Updated kernel packages that fix two security issues and two bugs are now
available for Red Hat Enterprise Linux 5.

Red Hat Product Security 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 packages contain the Linux kernel, the core of any Linux
operating system.

• An integer overflow flaw was found in the way the Linux kernel's Frame

Buffer device implementation mapped kernel memory to user space via the
mmap syscall. A local user able to access a frame buffer device file
(/dev/fb*) could possibly use this flaw to escalate their privileges on the
system. (CVE-2013-2596, Important)

• It was found that the Xen hypervisor x86 CPU emulator implementation did

not correctly handle certain instructions with segment overrides,
potentially resulting in a memory corruption. A malicious guest user could
use this flaw to read arbitrary data relating to other guests, cause a
denial of service on the host, or potentially escalate their privileges on
the host. (CVE-2015-2151, Important)

This update also fixes the following bugs:

• Previously, the CPU power of a CPU group could be zero. As a consequence,

a kernel panic occurred at "find_busiest_group+570" with do_divide_error.
The provided patch ensures that the division is only performed if the CPU
power is not zero, and the aforementioned panic no longer occurs.
(BZ#1209728)

• Prior to this update, a bug occurred when performing an online resize of

an ext4 file system which had been previously converted from ext3. As a
consequence, the kernel crashed. The provided patch fixes online resizing
for such file systems by limiting the blockgroup search loop for non-extent
files, and the mentioned kernel crash no longer occurs. (BZ#1301100)

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct 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.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 1034490 - CVE-2013-2596 kernel: integer overflow in fb_mmap
• BZ - 1196274 - CVE-2015-2151 xen: hypervisor memory corruption due to x86 emulator flaw (xsa123)

CVEs

• CVE-2013-2596
• CVE-2015-2151

References

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