kernel security update

CentOS Errata and Security Advisory CESA-2008:0957

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

• the Xen implementation did not prevent applications running in a
  para-virtualized guest from modifying CR4 TSC. This could cause a local
  denial of service. (CVE-2007-5907, Important)

• Tavis Ormandy reported missing boundary checks in the Virtual Dynamic
  Shared Objects (vDSO) implementation. This could allow a local unprivileged
  user to cause a denial of service or escalate privileges. (CVE-2008-3527,
  Important)

• the do_truncate() and generic_file_splice_write() functions did not clear
  the setuid and setgid bits. This could allow a local unprivileged user to
  obtain access to privileged information. (CVE-2008-4210, CVE-2008-3833,
  Important)

• a flaw was found in the Linux kernel splice implementation. This could
  cause a local denial of service when there is a certain failure in the
  add_to_page_cache_lru() function. (CVE-2008-4302, Important)

• a flaw was found in the Linux kernel when running on AMD64 systems.
  During a context switch, EFLAGS were being neither saved nor restored. This
  could allow a local unprivileged user to cause a denial of service.
  (CVE-2006-5755, Low)

• a flaw was found in the Linux kernel virtual memory implementation. This
  could allow a local unprivileged user to cause a denial of service.
  (CVE-2008-2372, Low)

• an integer overflow was discovered in the Linux kernel Datagram
  Congestion Control Protocol (DCCP) implementation. This could allow a
  remote attacker to cause a denial of service. By default, remote DCCP is
  blocked by SELinux. (CVE-2008-3276, Low)

In addition, these updated packages fix the following bugs:

• random32() seeding has been improved.

• in a multi-core environment, a race between the QP async event-handler
  and the destro_qp() function could occur. This led to unpredictable results
  during invalid memory access, which could lead to a kernel crash.

• a format string was omitted in the call to the request_module() function.

• a stack overflow caused by an infinite recursion bug in the binfmt_misc
  kernel module was corrected.

• the ata_scsi_rbuf_get() and ata_scsi_rbuf_put() functions now check for
  scatterlist usage before calling kmap_atomic().

• a sentinel NUL byte was added to the device_write() function to ensure
  that lspace.name is NUL-terminated.

• in the character device driver, a range_is_allowed() check was added to
  the read_mem() and write_mem() functions. It was possible for an
  illegitimate application to bypass these checks, and access /dev/mem beyond
  the 1M limit by calling mmap_mem() instead. Also, the parameters of
  range_is_allowed() were changed to cleanly handle greater than 32-bits of
  physical address on 32-bit architectures.

• some of the newer Nehalem-based systems declare their CPU DSDT entries as
  type “Alias”. During boot, this caused an “Error attaching device data”
  message to be logged.

• the evtchn event channel device lacked locks and memory barriers. This
  has led to xenstore becoming unresponsive on the Itanium® architecture.

• sending of gratuitous ARP packets in the Xen frontend network driver is
  now delayed until the backend signals that its carrier status has been
  processed by the stack.

• on forcedeth devices, whenever setting ethtool parameters for link speed,
  the device could stop receiving interrupts.

• the CIFS ‘forcedirectio’ option did not allow text to be appended to files.

• the gettimeofday() function returned a backwards time on Intel® 64.

• residual-count corrections during UNDERRUN handling were added to the
  qla2xxx driver.

• the fix for a small quirk was removed for certain Adaptec controllers for
  which it caused problems.

• the “xm trigger init” command caused a domain panic if a userland
  application was running on a guest on the Intel® 64 architecture.

Users of kernel should upgrade to these updated packages, which contain
backported patches to correct these issues.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2008-November/077531.html
https://lists.centos.org/pipermail/centos-announce/2008-November/077532.html
https://lists.centos.org/pipermail/centos-announce/2008-November/090312.html
https://lists.centos.org/pipermail/centos-announce/2008-November/090313.html

Affected packages:
kernel
kernel-PAE
kernel-PAE-devel
kernel-debug
kernel-debug-devel
kernel-devel
kernel-doc
kernel-headers
kernel-xen
kernel-xen-devel

Upstream details at:
https://access.redhat.com/errata/RHSA-2008:0957