RHSA-2017:2444 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise MRG 2.

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.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• A use-after-free flaw was found in the Linux kernel which enables a race condition in the L2TPv3 IP Encapsulation feature. A local user could use this flaw to escalate their privileges or crash the system. (CVE-2016-10200, Important)
• A flaw was found that can be triggered in keyring_search_iterator in keyring.c if type->match is NULL. A local user could use this flaw to crash the system or, potentially, escalate their privileges. (CVE-2017-2647, Important)
• The lrw_crypt() function in 'crypto/lrw.c' in the Linux kernel before 4.5 allows local users to cause a system crash and a denial of service by the NULL pointer dereference via accept(2) system call for AF_ALG socket without calling setkey() first to set a cipher key. (CVE-2015-8970, Moderate)

Red Hat would like to thank Igor Redko (Virtuozzo) and Andrey Ryabinin (Virtuozzo) for reporting CVE-2017-2647 and Igor Redko (Virtuozzo) and Vasily Averin (Virtuozzo) for reporting CVE-2015-8970.

Bug Fix(es):

• Writing model-specific register (MSR) registers during intel_idle initialization could previously cause exceptions. Consequently, a kernel panic occurred during this initialization. The function call to write to the MSR with

exception handling was modified to use wrmsrl_safe() instead of wrmsrl(). In this scenario, the kernel no longer panics. (BZ#1447438)

• The ixgbe driver was using incorrect bitwise operations on received PTP flags. Consequently, systems that were using the ixgbe driver could not synchronize time using PTP. The provided patch corrected the bitwise operations on received PTP flags allowing these system to correctly synchronize time using PTP. (BZ#1469795) (BZ#1451821)

The kernel-rt packages have been upgraded to version 3.10.0-514.rt56.230,
which provides a number of security and bug fixes over the previous
version. (BZ#1463427)

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.

Affected Products

• MRG Realtime 2 x86_64

Fixes

• BZ - 1386286 - CVE-2015-8970 kernel: crypto: GPF in lrw_crypt caused by null-deref
• BZ - 1428353 - CVE-2017-2647 kernel: Null pointer dereference in search_keyring
• BZ - 1430347 - CVE-2016-10200 kernel: l2tp: Race condition in the L2TPv3 IP encapsulation feature
• BZ - 1437675 - ftrace: pull upstream commits for correct selftest operation
• BZ - 1463427 - update the MRG 2.5.z 3.10 kernel-rt sources

CVEs

• CVE-2015-8970
• CVE-2016-10200
• CVE-2017-2647

References

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