kernel, perf, python security update

CentOS Errata and Security Advisory CESA-2017:0892

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

Security Fix(es):

• A race condition flaw was found in the N_HLDC Linux kernel driver when accessing n_hdlc.tbuf list that can lead to double free. A local, unprivileged user able to set the HDLC line discipline on the tty device could use this flaw to increase their privileges on the system. (CVE-2017-2636, Important)

• A flaw was found in the Linux kernel’s implementation of seq_file where a local attacker could manipulate memory in the put() function pointer. This could lead to memory corruption and possible privileged escalation. (CVE-2016-7910, Moderate)

Red Hat would like to thank Alexander Popov for reporting CVE-2017-2636.

Bug Fix(es):

• Previously, Chelsio firmware included an incorrectly-formatted firmware bin file. As a consequence, the firmware could not be flashed. This update provides a firmware bin file that is formatted correctly. As a result, Chelsio firmware can now be flashed successfully. (BZ#1433865)

• When multiple simultaneous processes attempted to read from the /proc/stat file, spinlock overhead was generated on Non-Uniform Memory Access (NUMA) systems. Consequently, a large amount of CPU was consumed. With this update, the underlying source code has been fixed to avoid taking spinlock when the interrupt line does not exist. As a result, the spinlock overhead is now generated less often, and multiple simultaneous processes can now read /proc/stat without consuming a large amount of CPU. (BZ#1428106)

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2017-April/084520.html

Affected packages:
kernel
kernel-abi-whitelists
kernel-debug
kernel-debug-devel
kernel-devel
kernel-doc
kernel-firmware
kernel-headers
perf
python-perf

Upstream details at:
https://access.redhat.com/errata/RHSA-2017:0892