7.8 - RHSA-2012:0333

Problem Description:

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. (BZ#783570)

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 https://access.redhat.com/knowledge/articles/11258

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 (http://bugzilla.redhat.com/):

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