(RHSA-2015:1778) Important: kernel security and bug fix update

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

• A flaw was found in the kernel’s implementation of the Berkeley Packet
  Filter (BPF). A local attacker could craft BPF code to crash the system by
  creating a situation in which the JIT compiler would fail to correctly
  optimize the JIT image on the last pass. This would lead to the CPU
  executing instructions that were not part of the JIT code. (CVE-2015-4700,
  Important)

• Two flaws were found in the way the Linux kernel’s networking
  implementation handled UDP packets with incorrect checksum values. A remote
  attacker could potentially use these flaws to trigger an infinite loop in
  the kernel, resulting in a denial of service on the system, or cause a
  denial of service in applications using the edge triggered epoll
  functionality. (CVE-2015-5364, CVE-2015-5366, Important)

• A flaw was found in the way the Linux kernel’s ext4 file system handled
  the “page size > block size” condition when the fallocate zero range
  functionality was used. A local attacker could use this flaw to crash the
  system. (CVE-2015-0275, Moderate)

• It was found that the Linux kernel’s keyring implementation would leak
  memory when adding a key to a keyring via the add_key() function. A local
  attacker could use this flaw to exhaust all available memory on the system.
  (CVE-2015-1333, Moderate)

• A race condition flaw was found in the way the Linux kernel’s SCTP
  implementation handled Address Configuration lists when performing Address
  Configuration Change (ASCONF). A local attacker could use this flaw to
  crash the system via a race condition triggered by setting certain ASCONF
  options on a socket. (CVE-2015-3212, Moderate)

• An information leak flaw was found in the way the Linux kernel’s Virtual
  Dynamic Shared Object (vDSO) implementation performed address
  randomization. A local, unprivileged user could use this flaw to leak
  kernel memory addresses to user-space. (CVE-2014-9585, Low)

Red Hat would like to thank Daniel Borkmann for reporting CVE-2015-4700,
and Canonical for reporting the CVE-2015-1333 issue. The CVE-2015-0275
issue was discovered by Xiong Zhou of Red Hat, and the CVE-2015-3212 issue
was discovered by Ji Jianwen of Red Hat Engineering.

This update also fixes several bugs. Refer to the following Knowledgebase
article for further information:

https://access.redhat.com/articles/1614563

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.