Synopsis

Important: kernel security and bug fix update

Type/Severity

Security Advisory: Important

Topic

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

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.

• A flaw was found in the way seunshare, a utility for running executables

under a different security context, used the capng_lock functionality of
the libcap-ng library. The subsequent invocation of suid root binaries that
relied on the fact that the setuid() system call, among others, also sets
the saved set-user-ID when dropping the binaries' process privileges, could
allow a local, unprivileged user to potentially escalate their privileges
on the system. Note: the fix for this issue is the kernel part of the
overall fix, and introduces the PR_SET_NO_NEW_PRIVS functionality and the
related SELinux exec transitions support. (CVE-2014-3215, Important)

• A use-after-free flaw was found in the way the Linux kernel's SCTP

implementation handled authentication key reference counting during INIT
collisions. A remote attacker could use this flaw to crash the system or,
potentially, escalate their privileges on the system. (CVE-2015-1421,
Important)

• It was found that the Linux kernel's KVM implementation did not ensure

that the host CR4 control register value remained unchanged across VM
entries on the same virtual CPU. A local, unprivileged user could use this
flaw to cause a denial of service on the system. (CVE-2014-3690, Moderate)

• An out-of-bounds memory access flaw was found in the syscall tracing

functionality of the Linux kernel's perf subsystem. A local, unprivileged
user could use this flaw to crash the system. (CVE-2014-7825, Moderate)

• An out-of-bounds memory access flaw was found in the syscall tracing

functionality of the Linux kernel's ftrace subsystem. On a system with
ftrace syscall tracing enabled, a local, unprivileged user could use this
flaw to crash the system, or escalate their privileges. (CVE-2014-7826,
Moderate)

• It was found that the Linux kernel memory resource controller's (memcg)

handling of OOM (out of memory) conditions could lead to deadlocks.
An attacker able to continuously spawn new processes within a single
memory-constrained cgroup during an OOM event could use this flaw to lock
up the system. (CVE-2014-8171, Moderate)

• A race condition flaw was found in the way the Linux kernel keys

management subsystem performed key garbage collection. A local attacker
could attempt accessing a key while it was being garbage collected, which
would cause the system to crash. (CVE-2014-9529, Moderate)

• A stack-based buffer overflow flaw was found in the TechnoTrend/Hauppauge

DEC USB device driver. A local user with write access to the corresponding
device could use this flaw to crash the kernel or, potentially, elevate
their privileges on the system. (CVE-2014-8884, Low)

• An information leak flaw was found in the way the Linux kernel's ISO9660

file system implementation accessed data on an ISO9660 image with RockRidge
Extension Reference (ER) records. An attacker with physical access to the
system could use this flaw to disclose up to 255 bytes of kernel memory.
(CVE-2014-9584, Low)

Red Hat would like to thank Andy Lutomirski for reporting CVE-2014-3215
and CVE-2014-3690, Robert Święcki for reporting CVE-2014-7825 and
CVE-2014-7826, and Carl Henrik Lunde for reporting CVE-2014-9584. The
CVE-2015-1421 issue was discovered by Sun Baoliang of Red Hat.

This update also fixes several bugs. Documentation for these changes is
available 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.

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

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

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 6.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 i386
• Red Hat Enterprise Linux Server - AUS 6.6 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 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 6.6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.6 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 6.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 6.6 x86_64
• Red Hat Enterprise Linux Server - TUS 6.6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1095855 - CVE-2014-3215 policycoreutils: local privilege escalation via seunshare
• BZ - 1153322 - CVE-2014-3690 kernel: kvm: vmx: invalid host cr4 handling across vm entries
• BZ - 1161565 - CVE-2014-7825 CVE-2014-7826 kernel: insufficient syscall number validation in perf and ftrace subsystems
• BZ - 1164266 - CVE-2014-8884 kernel: usb: buffer overflow in ttusb-dec
• BZ - 1179813 - CVE-2014-9529 kernel: memory corruption or panic during key garbage collection
• BZ - 1180119 - CVE-2014-9584 kernel: isofs: unchecked printing of ER records
• BZ - 1196581 - CVE-2015-1421 kernel: net: slab corruption from use after free on INIT collisions
• BZ - 1198109 - CVE-2014-8171 kernel: memcg: OOM handling DoS

CVEs

• CVE-2014-7826
• CVE-2014-7825
• CVE-2014-3690
• CVE-2014-8884
• CVE-2015-1421
• CVE-2014-9529
• CVE-2014-9584
• CVE-2014-8171
• CVE-2014-3215

References