(RHSA-2015:0102) 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 way the Linux kernel’s SCTP implementation
  validated INIT chunks when performing Address Configuration Change
  (ASCONF). A remote attacker could use this flaw to crash the system by
  sending a specially crafted SCTP packet to trigger a NULL pointer
  dereference on the system. (CVE-2014-7841, Important)

• A race condition flaw was found in the way the Linux kernel’s mmap(2),
  madvise(2), and fallocate(2) system calls interacted with each other while
  operating on virtual memory file system files. A local user could use this
  flaw to cause a denial of service. (CVE-2014-4171, Moderate)

• A NULL pointer dereference flaw was found in the way the Linux kernel’s
  Common Internet File System (CIFS) implementation handled mounting of file
  system shares. A remote attacker could use this flaw to crash a client
  system that would mount a file system share from a malicious server.
  (CVE-2014-7145, Moderate)

• A flaw was found in the way the Linux kernel’s splice() system call
  validated its parameters. On certain file systems, a local, unprivileged
  user could use this flaw to write past the maximum file size, and thus
  crash the system. (CVE-2014-7822, Moderate)

• It was found that the parse_rock_ridge_inode_internal() function of the
  Linux kernel’s ISOFS implementation did not correctly check relocated
  directories when processing Rock Ridge child link (CL) tags. An attacker
  with physical access to the system could use a specially crafted ISO image
  to crash the system or, potentially, escalate their privileges on the
  system. (CVE-2014-5471, CVE-2014-5472, Low)

Red Hat would like to thank Akira Fujita of NEC for reporting the
CVE-2014-7822 issue. The CVE-2014-7841 issue was discovered by Liu Wei of
Red Hat.

This update also fixes the following bugs:

• Previously, a kernel panic could occur if a process reading from a locked
  NFS file was killed and the lock was not released properly before the read
  operations finished. Consequently, the system crashed. The code handling
  file locks has been fixed, and instead of halting, the system now emits a
  warning about the unreleased lock. (BZ#1172266)

• A race condition in the command abort handling logic of the ipr device
  driver could cause the kernel to panic when the driver received a response
  to an abort command prior to receiving other responses to the aborted
  command due to the support for multiple interrupts. With this update, the
  abort handler waits for the aborted command’s responses first before
  completing an abort operation. (BZ#1162734)

• Previously, a race condition could occur when changing a Page Table Entry
  (PTE) or a Page Middle Directory (PMD) to “pte_numa” or “pmd_numa”,
  respectively, causing the kernel to crash. This update removes the BUG_ON()
  macro from the __handle_mm_fault() function, preventing the kernel panic in
  the aforementioned scenario. (BZ#1170662)

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.