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Red Hat: 2012:0333-01: kernel-rt: Important Advisory Print E-mail
User Rating:      How can I rate this item?
Posted by Benjamin D. Thomas   
RedHat Linux Updated kernel-rt packages that fix multiple security issues and various bugs are now available for Red Hat Enterprise MRG 2.1. The Red Hat Security Response Team has rated this update as having [More...]
                   Red Hat Security Advisory

Synopsis:          Important: kernel-rt security and bug fix update
Advisory ID:       RHSA-2012:0333-01
Product:           Red Hat Enterprise MRG for RHEL-6
Advisory URL:
Issue date:        2012-02-23
CVE Names:         CVE-2011-2918 CVE-2011-4077 CVE-2011-4097 
                   CVE-2011-4110 CVE-2011-4127 CVE-2011-4131 
                   CVE-2011-4132 CVE-2012-0038 CVE-2012-0044 
                   CVE-2012-0207 CVE-2012-0810 

1. Summary:

Updated kernel-rt packages that fix multiple security issues and various
bugs are now available for Red Hat Enterprise MRG 2.1.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

MRG Realtime for RHEL 6 Server v.2 - noarch, x86_64

3. Description:

These packages contain the Linux kernel.

Security fixes:

* SG_IO ioctl SCSI requests on partitions or LVM volumes could be passed to
the underlying block device, allowing a privileged user to bypass
restrictions and gain read and write access (and be able to issue other
SCSI commands) to the entire block device. (CVE-2011-4127, Important)

* A local, unprivileged user could use an integer overflow flaw in
drm_mode_dirtyfb_ioctl() to cause a denial of service or escalate their
privileges. (CVE-2012-0044, Important)

* A local, unprivileged user could use a flaw in the Performance Events
implementation to cause a denial of service. (CVE-2011-2918, Moderate)

* A local, unprivileged user could use flaws in the XFS file system
implementation to cause a denial of service or escalate their privileges by
mounting a specially-crafted disk. (CVE-2011-4077, CVE-2012-0038, Moderate)

* A local, unprivileged user could use a flaw in the Out of Memory (OOM)
killer to monopolize memory, have their process skipped by the OOM killer,
or cause other tasks to be terminated. (CVE-2011-4097, Moderate)

* A local, unprivileged user could use a flaw in the key management
facility to cause a denial of service. (CVE-2011-4110, Moderate)

* A malicious Network File System version 4 (NFSv4) server could return a
crafted reply to a GETACL request, causing a denial of service on the
client. (CVE-2011-4131, Moderate)

* A local attacker could use a flaw in the Journaling Block Device (JBD) to
crash the system by mounting a specially-crafted ext3 or ext4 disk.
(CVE-2011-4132, Moderate)

* A flaw in igmp_heard_query() could allow an attacker, who is able to send
certain IGMP (Internet Group Management Protocol) packets to a target
system, to cause a denial of service. (CVE-2012-0207, Moderate)

* If lock contention during signal sending occurred when in a software
interrupt handler that is using the per-CPU debug stack, the task could be
scheduled out on the realtime kernel, possibly leading to debug stack
corruption. A local, unprivileged user could use this flaw to cause a
denial of service. (CVE-2012-0810, Moderate)

Red Hat would like to thank Chen Haogang for reporting CVE-2012-0044;
Wang Xi for reporting CVE-2012-0038; Shubham Goyal for reporting
CVE-2011-4097; Andy Adamson for reporting CVE-2011-4131; and Simon McVittie
for reporting CVE-2012-0207.

Bug fixes:

* When a sleeping task, waiting on a futex (fast userspace mutex), tried to
get the spin_lock(hb->lock) RT-mutex, if the owner of the futex released
the lock, the sleeping task was put on a futex proxy lock. Consequently,
the sleeping task was blocked on two locks and eventually terminated in the
BUG_ON() function. With this update, the WAKEUP_INPROGRESS pseudo-lock has
been added to be used as a proxy lock. This pseudo-lock tells the sleeping
task that it is being woken up so that the task no longer tries to get the
second lock. Now, the futex code works as expected and sleeping tasks no
longer crash in the described scenario. (BZ#784733)

* When the CONFIG_CRYPTO_FIPS configuration option was disabled, some
services such as sshd and ipsec, while working properly, returned warning
messages regarding this missing option during start up. With this update,
CONFIG_CRYPTO_FIPS has been enabled and no warning messages are now
returned in the described scenario. (BZ#786145)

* Previously, when a read operation on a loop device failed, the data
successfully read from the device was not cleared and could eventually
leak. This bug has been fixed and all data are now properly cleared in the
described scenario. (BZ#761420)

* Due to an assembler-sourced object, the perf utility (from the perf-rt
package) for AMD64 and Intel 64 architectures contained an executable
stack. This update adds the ".note.GNU-stack" section definition to the
bench/mem-memcpy-x86-64-asm.S component of perf, with all flags disabled,
and perf no longer contains an executable stack, thus fixing this bug.

4. Solution:

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

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

5. Bugs fixed (

730706 - CVE-2011-2918 kernel: perf: Fix software event overflow
747106 - CVE-2011-4131 kernel: nfs4_getfacl decoding kernel oops
749156 - CVE-2011-4077 kernel: xfs: potential buffer overflow in xfs_readlink()
750399 - CVE-2011-4097 kernel: oom_badness() integer overflow
751297 - CVE-2011-4110 kernel: keys: NULL pointer deref in the user-defined key type
752375 - CVE-2011-4127 kernel: possible privilege escalation via SG_IO ioctl
753341 - CVE-2011-4132 kernel: jbd/jbd2: invalid value of first log block leads to oops
772867 - CVE-2012-0207 kernel: igmp: Avoid zero delay when receiving odd mixture of IGMP queries
772894 - CVE-2012-0044 kernel: drm: integer overflow in drm_mode_dirtyfb_ioctl()
773280 - CVE-2012-0038 kernel: xfs heap overflow
784733 - BUG at kernel/rtmutex.c:472 MRG 2.1 3.0.9-rt26.45.el6rt.x86_64 kernel
786145 - missing /proc/sys/crypto/fips_enabled in 3.0.9 causes openssh errors
794557 - CVE-2012-0810 kernel-rt: stack corruption when task gets scheduled out using the debug stack

6. Package List:

MRG Realtime for RHEL 6 Server v.2:




These packages are GPG signed by Red Hat for security.  Our key and 
details on how to verify the signature are available from

7. References:

8. Contact:

The Red Hat security contact is .  More contact
details at

Copyright 2012 Red Hat, Inc.
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