(RHSA-2011:1350) Important: kernel security, bug fix, and enhancement update

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

This update fixes the following security issues:

• Flaws in the AGPGART driver implementation when handling certain IOCTL
  commands could allow a local user to cause a denial of service or escalate
  their privileges. (CVE-2011-1745, CVE-2011-2022, Important)

• An integer overflow flaw in agp_allocate_memory() could allow a local
  user to cause a denial of service or escalate their privileges.
  (CVE-2011-1746, Important)

• A race condition flaw was found in the Linux kernel’s eCryptfs
  implementation. A local attacker could use the mount.ecryptfs_private
  utility to mount (and then access) a directory they would otherwise not
  have access to. Note: To correct this issue, the RHSA-2011:1241
  ecryptfs-utils update, which provides the user-space part of the fix, must
  also be installed. (CVE-2011-1833, Moderate)

• A denial of service flaw was found in the way the taskstats subsystem
  handled the registration of process exit handlers. A local, unprivileged
  user could register an unlimited amount of these handlers, leading to
  excessive CPU time and memory use. (CVE-2011-2484, Moderate)

• A flaw was found in the way mapping expansions were handled. A local,
  unprivileged user could use this flaw to cause a wrapping condition,
  triggering a denial of service. (CVE-2011-2496, Moderate)

• A flaw was found in the Linux kernel’s Performance Events implementation.
  It could falsely lead the NMI (Non-Maskable Interrupt) Watchdog to detect a
  lockup and panic the system. A local, unprivileged user could use this flaw
  to cause a denial of service (kernel panic) using the perf tool.
  (CVE-2011-2521, Moderate)

• A flaw in skb_gro_header_slow() in the Linux kernel could lead to GRO
  (Generic Receive Offload) fields being left in an inconsistent state. An
  attacker on the local network could use this flaw to trigger a denial of
  service. GRO is enabled by default in all network drivers that support it.
  (CVE-2011-2723, Moderate)

• A flaw was found in the way the Linux kernel’s Performance Events
  implementation handled PERF_COUNT_SW_CPU_CLOCK counter overflow. A local,
  unprivileged user could use this flaw to cause a denial of service.
  (CVE-2011-2918, Moderate)

• A flaw was found in the Linux kernel’s Trusted Platform Module (TPM)
  implementation. A local, unprivileged user could use this flaw to leak
  information to user-space. (CVE-2011-1160, Low)

• Flaws were found in the tpacket_rcv() and packet_recvmsg() functions in
  the Linux kernel. A local, unprivileged user could use these flaws to leak
  information to user-space. (CVE-2011-2898, Low)

Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting
CVE-2011-1745, CVE-2011-2022, CVE-2011-1746, and CVE-2011-2484; the Ubuntu
Security Team for reporting CVE-2011-1833; Robert Swiecki for reporting
CVE-2011-2496; Li Yu for reporting CVE-2011-2521; Brent Meshier for
reporting CVE-2011-2723; and Peter Huewe for reporting CVE-2011-1160. The
Ubuntu Security Team acknowledges Vasiliy Kulikov of Openwall and Dan
Rosenberg as the original reporters of CVE-2011-1833.

This update also fixes various bugs and adds one enhancement. Documentation
for these changes will be available shortly from the Technical Notes
document linked to in the References section.

Users should upgrade to these updated packages, which contain backported
patches to correct these issues, and fix the bugs and add the enhancement
noted in the Technical Notes. The system must be rebooted for this update
to take effect.