7.2 - RHSA-2016:2133

Problem Description:

An update for kernel is now available for Red Hat Enterprise Linux 6.4 Advanced Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Server AUS (v. 6.4) - noarch, x86_64 Red Hat Enterprise Linux Server Optional AUS (v. 6.4) - x86_64

3. Description:

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

Security Fix(es):

* A race condition was found in the way the Linux kernel's memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged, local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system. (CVE-2016-5195, Important)

* A flaw was found in the Linux kernel's keyring handling code: the key_reject_and_link() function could be forced to free an arbitrary memory block. An attacker could use this flaw to trigger a use-after-free condition on the system, potentially allowing for privilege escalation. (CVE-2016-4470, Important)

Red Hat would like to thank Phil Oester for reporting CVE-2016-5195. The CVE-2016-4470 issue was discovered by David Howells (Red Hat).

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

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

The system must be rebooted for this update to take effect.

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

1341716 - CVE-2016-4470 kernel: Uninitialized variable in request_key handling causes kernel crash in error handling path 1384344 - CVE-2016-5195 kernel: mm: privilege escalation via MAP_PRIVATE COW breakage