RHSA-2015:0751 - Security Advisory

Topic

Updated kernel-rt packages that fix two security issues and several bugs
are now available for Red Hat Enterprise MRG 2.5.

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

• It was found that the Linux kernel's Infiniband subsystem did not

properly sanitize input parameters while registering memory regions from
user space via the (u)verbs API. A local user with access to a
/dev/infiniband/uverbsX device could use this flaw to crash the system or,
potentially, escalate their privileges on the system. (CVE-2014-8159,
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)

Red Hat would like to thank Mellanox for reporting the CVE-2014-8159 issue.
The CVE-2015-1421 issue was discovered by Sun Baoliang of Red Hat.

The MRG-Realtime 3.10 kernel-rt sources have been updated to include the
following bug fixes:

• The kdump service could become unresponsive due to a deadlock in the

kernel call ioapic_lock.

• Attempt to make metadata changes such as creating a thin device or

snapshot thin device did not error out cleanly.

(BZ#1201384)

This update also fixes the following bug:

• The MRG kernel scheduler code was missing checks for the PREEMPT_LAZY

flag allowing tasks to be preempted more times than necessary causing
latency spikes on the system. Additional checks for the PREEMPT_LAZY flag
were added to the check_preempt_wakeup() and check_preempt_curr() functions
in the scheduler code so that preempt wakeups were reduced and these
latency spikes were removed. (BZ#1157949)

All kernel-rt users are advised to upgrade to these updated packages, which
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

• MRG Realtime 2 x86_64

Fixes

• BZ - 1181166 - CVE-2014-8159 kernel: infiniband: uverbs: unprotected physical memory access
• BZ - 1196581 - CVE-2015-1421 kernel: net: slab corruption from use after free on INIT collisions
• BZ - 1201384 - RFE: rebase the 3.10 kernel-rt

CVEs

• CVE-2014-8159
• CVE-2015-1421

References

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