RHSA-2014:0771: Important: kernel security and bug fix update

The kernel packages contain the Linux kernel, the core of any Linuxoperating system. A flaw was found in the way the Linux kernel's futex subsystem handled the requeuing of certain Priority Inheritance (PI) futexes. A local,unprivileged user could use this flaw to escalate their privileges on thesystem. (CVE-2014-3153, Important) A flaw was found in the way the Linux kernel's floppy driver handled user space provided data in certain error code paths while processing FDRAWCMDIOCTL commands. A local user with write access to /dev/fdX could use thisflaw to free (using the kfree() function) arbitrary kernel memory.(CVE-2014-1737, Important) It was found that the Linux kernel's floppy driver leaked internal kernel memory addresses to user space during the processing of the FDRAWCMD IOCTLcommand. A local user with write access to /dev/fdX could use this flaw toobtain information about the kernel heap arrangement. (CVE-2014-1738, Low)Note: A local user with write access to /dev/fdX could use these two flaws(CVE-2014-1737 in combination with CVE-2014-1738) to escalate theirprivileges on the system. It was discovered that the procnsfollowlink() function did not properly return the LASTBIND value in the last pathname component as isexpected for procfs symbolic links, which could lead to excessive freeingof memory and consequent slab corruption. A local, unprivileged user coulduse this flaw to crash the system. (CVE-2014-0203, Moderate) A flaw was found in the way the Linux kernel handled exceptions when user-space applications attempted to use the linkage stack. On IBM S/390systems, a local, unprivileged user could use this flaw to crash thesystem. (CVE-2014-2039, Moderate) An invalid pointer dereference flaw was found in the Marvell 8xxx Libertas WLAN (libertas) driver in the Linux kernel. A local user able towrite to a file that is provided by the libertas driver and located on thedebug file system (debugfs) could use this flaw to crash the system. Note:The debugfs file system must be mounted locally to exploit this issue.It is not mounted by default. (CVE-2013-6378, Low) A denial of service flaw was discovered in the way the Linux kernel's SELinux implementation handled files with an empty SELinux securitycontext. A local user who has the CAPMACADMIN capability could use thisflaw to crash the system. (CVE-2014-1874, Low)Red Hat would like to thank Kees Cook of Google for reportingCVE-2014-3153, Matthew Daley for reporting CVE-2014-1737 and CVE-2014-1738,and Vladimir Davydov of Parallels for reporting CVE-2014-0203. Googleacknowledges Pinkie Pie as the original reporter of CVE-2014-3153.This update also fixes several bugs. Documentation for these changes willbe available shortly from the Technical Notes document linked to in theReferences section.All kernel users are advised to upgrade to these updated packages, whichcontain backported patches to correct these issues. The system must berebooted for this update to take effect.