Synopsis

Important: kernel security, bug fix, and enhancement update

Type/Severity

Security Advisory: Important

Topic

Updated kernel packages that fix multiple security issues, several bugs,
and add one enhancement are now available for Red Hat Enterprise Linux 5.

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

• A buffer overflow flaw was found in the way the qeth_snmp_command()

function in the Linux kernel's QETH network device driver implementation
handled SNMP IOCTL requests with an out-of-bounds length. A local,
unprivileged user could use this flaw to crash the system or, potentially,
escalate their privileges on the system. (CVE-2013-6381, Important)

• A flaw was found in the way the ipc_rcu_putref() function in the Linux

kernel's IPC implementation handled reference counter decrementing.
A local, unprivileged user could use this flaw to trigger an Out of Memory
(OOM) condition and, potentially, crash the system. (CVE-2013-4483,
Moderate)

• It was found that the Xen hypervisor implementation did not correctly

check privileges of hypercall attempts made by HVM guests, allowing
hypercalls to be invoked from protection rings 1 and 2 in addition to ring
0. A local attacker in an HVM guest able to execute code on privilege
levels 1 and 2 could potentially use this flaw to further escalate their
privileges in that guest. Note: Xen HVM guests running unmodified versions
of Red Hat Enterprise Linux and Microsoft Windows are not affected by this
issue because they are known to only use protection rings 0 (kernel) and 3
(userspace). (CVE-2013-4554, Moderate)

• A flaw was found in the way the Linux kernel's Adaptec RAID controller

(aacraid) checked permissions of compat IOCTLs. A local attacker could use
this flaw to bypass intended security restrictions. (CVE-2013-6383,
Moderate)

• It was found that, under specific circumstances, a combination of write

operations to write-combined memory and locked CPU instructions may cause a
core hang on certain AMD CPUs (for more information, refer to AMD CPU
erratum 793 linked in the References section). A privileged user in a guest
running under the Xen hypervisor could use this flaw to cause a denial of
service on the host system. This update adds a workaround to the Xen
hypervisor implementation, which mitigates the AMD CPU issue. Note: this
issue only affects AMD Family 16h Models 00h-0Fh Processors. Non-AMD CPUs
are not vulnerable. (CVE-2013-6885, Moderate)

• It was found that certain protocol handlers in the Linux kernel's

networking implementation could set the addr_len value without initializing
the associated data structure. A local, unprivileged user could use this
flaw to leak kernel stack memory to user space using the recvmsg, recvfrom,
and recvmmsg system calls. (CVE-2013-7263, Low)

• A flaw was found in the way the get_dumpable() function return value was

interpreted in the ptrace subsystem of the Linux kernel. When
'fs.suid_dumpable' was set to 2, a local, unprivileged local user could
use this flaw to bypass intended ptrace restrictions and obtain
potentially sensitive information. (CVE-2013-2929, Low)

Red Hat would like to thank Vladimir Davydov of Parallels for reporting
CVE-2013-4483 and the Xen project for reporting CVE-2013-4554 and
CVE-2013-6885. Upstream acknowledges Jan Beulich as the original reporter
of CVE-2013-4554 and CVE-2013-6885.

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

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add this
enhancement. 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/site/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 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 - 1024854 - CVE-2013-4483 kernel: ipc: ipc_rcu_putref refcount races
• BZ - 1028148 - CVE-2013-2929 kernel: exec/ptrace: get_dumpable() incorrect tests
• BZ - 1029111 - CVE-2013-4554 kernel: xen: hypercalls exposed to privilege rings 1 and 2 of HVM guests
• BZ - 1033530 - CVE-2013-6383 Kernel: AACRAID Driver compat IOCTL missing capability check
• BZ - 1033600 - CVE-2013-6381 Kernel: qeth: buffer overflow in snmp ioctl
• BZ - 1035823 - CVE-2013-6885 hw: AMD CPU erratum may cause core hang
• BZ - 1035875 - CVE-2013-7263 CVE-2013-7265 Kernel: net: leakage of uninitialized memory to user-space via recv syscalls

CVEs

• CVE-2013-6383
• CVE-2013-2929
• CVE-2013-6381
• CVE-2013-7263
• CVE-2013-4554
• CVE-2013-6885
• CVE-2013-4483

References