RHSA-2014:0771 - Security Advisory

Topic

Updated kernel packages that fix multiple 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
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 flaw was found in the way the Linux kernel's futex subsystem handled

the requeuing of certain Priority Inheritance (PI) futexes. A local,
unprivileged user could use this flaw to escalate their privileges on the
system. (CVE-2014-3153, Important)

• A flaw was found in the way the Linux kernel's floppy driver handled user

space provided data in certain error code paths while processing FDRAWCMD
IOCTL commands. A local user with write access to /dev/fdX could use this
flaw to free (using the kfree() function) arbitrary kernel memory.
(CVE-2014-1737, Important)

• It was found that the Linux kernel's floppy driver leaked internal kernel

memory addresses to user space during the processing of the FDRAWCMD IOCTL
command. A local user with write access to /dev/fdX could use this flaw to
obtain information about the kernel heap arrangement. (CVE-2014-1738, Low)

Note: A local user with write access to /dev/fdX could use these two flaws
(CVE-2014-1737 in combination with CVE-2014-1738) to escalate their
privileges on the system.

• It was discovered that the proc_ns_follow_link() function did not

properly return the LAST_BIND value in the last pathname component as is
expected for procfs symbolic links, which could lead to excessive freeing
of memory and consequent slab corruption. A local, unprivileged user could
use this flaw to crash the system. (CVE-2014-0203, Moderate)

• A flaw was found in the way the Linux kernel handled exceptions when

user-space applications attempted to use the linkage stack. On IBM S/390
systems, a local, unprivileged user could use this flaw to crash the
system. (CVE-2014-2039, Moderate)

• An invalid pointer dereference flaw was found in the Marvell 8xxx

Libertas WLAN (libertas) driver in the Linux kernel. A local user able to
write to a file that is provided by the libertas driver and located on the
debug file system (debugfs) could use this flaw to crash the system. Note:
The debugfs file system must be mounted locally to exploit this issue.
It is not mounted by default. (CVE-2013-6378, Low)

• A denial of service flaw was discovered in the way the Linux kernel's

SELinux implementation handled files with an empty SELinux security
context. A local user who has the CAP_MAC_ADMIN capability could use this
flaw to crash the system. (CVE-2014-1874, Low)

Red Hat would like to thank Kees Cook of Google for reporting
CVE-2014-3153, Matthew Daley for reporting CVE-2014-1737 and CVE-2014-1738,
and Vladimir Davydov of Parallels for reporting CVE-2014-0203. Google
acknowledges Pinkie Pie as the original reporter of CVE-2014-3153.

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.

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.

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 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• 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 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 6.5 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.5 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 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386
• Red Hat Enterprise Linux EUS Compute Node 6.5 x86_64
• Red Hat Enterprise Linux Server - AUS 6.5 x86_64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1033578 - CVE-2013-6378 Kernel: drivers: libertas: potential oops in debugfs
• BZ - 1062356 - CVE-2014-1874 Kernel: SELinux: local denial-of-service
• BZ - 1067558 - CVE-2014-2039 Kernel: s390: crash due to linkage stack instructions
• BZ - 1094287 - ixgbevf prematurely strips VLAN tags [rhel-6.5.z]
• BZ - 1094299 - CVE-2014-1737 CVE-2014-1738 kernel: block: floppy: privilege escalation via FDRAWCMD floppy ioctl command
• BZ - 1094363 - CVE-2014-0203 kernel: fs: slab corruption due to the invalid last component type during do_filp_open()
• BZ - 1103626 - CVE-2014-3153 kernel: futex: pi futexes requeue issue

CVEs

• CVE-2013-6378
• CVE-2014-1874
• CVE-2014-1737
• CVE-2014-1738
• CVE-2014-2039
• CVE-2014-3153
• CVE-2014-0203

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.5_Technical_Notes/kernel.html