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HistoryJul 14, 2009 - 12:00 a.m.

(RHSA-2009:1157) Important: kernel-rt security and bug fix update






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

Security fixes:

  • a flaw was found in the Intel PRO/1000 network driver in the Linux
    kernel. Frames with sizes near the MTU of an interface may be split across
    multiple hardware receive descriptors. Receipt of such a frame could leak
    through a validation check, leading to a corruption of the length check. A
    remote attacker could use this flaw to send a specially-crafted packet that
    would cause a denial of service or code execution. (CVE-2009-1385,

  • Michael Tokarev reported a flaw in the Realtek r8169 Ethernet driver in
    the Linux kernel. This driver allowed interfaces using this driver to
    receive frames larger than what could be handled. This could lead to a
    remote denial of service or code execution. (CVE-2009-1389, Important)

  • 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-2009-1633, Important)

  • 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 deadlock flaw was found in the Linux kernel splice implementation. This
    deadlock could occur during interactions between the
    generic_file_splice_write() and splice_from_pipe() functions, possibly
    leading to a partial denial of service on the file system partition where
    the deadlock occurs. (CVE-2009-1961, Moderate)

Bug fixes:

  • a stack buffer used by get_event_name() was not large enough to
    accommodate the nul terminator that sprintf() writes. In some cases, this
    could lead to an invalid pointer or a kernel panic. With this update, the
    function is modified to allow space for the nul terminator. (BZ#503902)

  • free_bootmem() was hard-coded to use node 0. This could have caused a
    kernel panic during boot on a NUMA system that happens to boot on a node
    other than node 0. With this update, free_bootmem() acts on the current
    node, resolving this issue. (BZ#503048)

  • CPU flag mishandling caused TSC clocksource synchronization to fail (TSC
    was marked unstable) on the Intel? microarchitecture (Nehalem). In
    addition, TSC clocksource checks added to the 64-bit kernel code are now
    present for i386 systems. Also, “/proc/cpuinfo” now shows TSC-related
    flags. (BZ#50289, BZ#508756)

  • barriers are used to make sure delayed work requested from threads is
    processed before continuing. run_workqueue(), however, exited before
    processing all barriers, causing threads to wait forever. In a reported
    case, this bug caused missing path issues for Device Mapper Multipathing.

  • calling pipe() with an invalid address caused a file descriptor leak.

  • the code to add “/dev/rtc” contained a printk statement without a log
    level prefix. (BZ#510099)

  • an extra check has been added to the realtime kernel to avoid a rare
    corruption of the FPU (Floating Point Unit) stack, which could occur if a
    task using FPU registers was preempted by an interruption. (BZ#509359)

  • fix a boot-up problem on HP ProLiant SL2x170z G6 and similar systems by
    adding Intel ICH10 controllers back to the ata_piix driver. (BZ#508783)

  • converts a UID comparison in AGP to a more secure capability check. By
    default, “/dev/agpgart” is accessible only to the root user. (BZ#505493)

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.