(RHSA-2009:1106) Important: kernel security and bug fix update

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

Security fixes:

• several flaws were found in the way the Linux kernel CIFS implementation
  handles Unicode strings. CIFS clients convert Unicode strings sent by a
  server to their local character sets, and then write those strings into
  memory. If a malicious server sent a long enough string, it could write
  past the end of the target memory region and corrupt other memory areas,
  possibly leading to a denial of service or privilege escalation on the
  client mounting the CIFS share. (CVE-2009-1439, CVE-2009-1633, Important)

• the Linux kernel Network File System daemon (nfsd) implementation did not
  drop the CAP_MKNOD capability when handling requests from local,
  unprivileged users. This flaw could possibly lead to an information leak or
  privilege escalation. (CVE-2009-1072, Moderate)

• Frank Filz reported the NFSv4 client was missing a file permission check
  for the execute bit in some situations. This could allow local,
  unprivileged users to run non-executable files on NFSv4 mounted file
  systems. (CVE-2009-1630, Moderate)

• a missing check was found in the hypervisor_callback() function in the
  Linux kernel provided by the kernel-xen package. This could cause a denial
  of service of a 32-bit guest if an application running in that guest
  accesses a certain memory location in the kernel. (CVE-2009-1758, Moderate)

• a flaw was found in the AGPGART driver. The agp_generic_alloc_page() and
  agp_generic_alloc_pages() functions did not zero out the memory pages they
  allocate, which may later be available to user-space processes. This flaw
  could possibly lead to an information leak. (CVE-2009-1192, Low)

Bug fixes:

• a race in the NFS client between destroying cached access rights and
  unmounting an NFS file system could have caused a system crash. “Busy
  inodes” messages may have been logged. (BZ#498653)

• nanosleep() could sleep several milliseconds less than the specified time
  on Intel Itanium®-based systems. (BZ#500349)

• LEDs for disk drives in AHCI mode may have displayed a fault state when
  there were no faults. (BZ#500120)

• ptrace_do_wait() reported tasks were stopped each time the process doing
  the trace called wait(), instead of reporting it once. (BZ#486945)

• epoll_wait() may have caused a system lockup and problems for
  applications. (BZ#497322)

• missing capabilities could possibly allow users with an fsuid other than
  0 to perform actions on some file system types that would otherwise be
  prevented. (BZ#497271)

• on NFS mounted file systems, heavy write loads may have blocked
  nfs_getattr() for long periods, causing commands that use stat(2), such as
  ls, to hang. (BZ#486926)

• in rare circumstances, if an application performed multiple O_DIRECT
  reads per virtual memory page and also performed fork(2), the buffer
  storing the result of the I/O may have ended up with invalid data.
  (BZ#486921)

• when using GFS2, gfs2_quotad may have entered an uninterpretable sleep
  state. (BZ#501742)

• with this update, get_random_int() is more random and no longer uses a
  common seed value, reducing the possibility of predicting the values
  returned. (BZ#499783)

• the “-fwrapv” flag was added to the gcc build options to prevent gcc from
  optimizing away wrapping. (BZ#501751)

• a kernel panic when enabling and disabling iSCSI paths. (BZ#502916)

• using the Broadcom NetXtreme BCM5704 network device with the tg3 driver
  caused high system load and very bad performance. (BZ#502837)

• “/proc/[pid]/maps” and “/proc/[pid]/smaps” can only be read by processes
  able to use the ptrace() call on a given process; however, certain
  information from “/proc/[pid]/stat” and “/proc/[pid]/wchan” could be used
  to reconstruct memory maps. (BZ#499546)

Users should upgrade to these updated packages, which contain backported
patches to correct these issues. The system must be rebooted for this
update to take effect.