RHSA-2014:0786: Important: kernel security, bug fix, and enhancement 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 use-after-free flaw was found in the way the pinginitsock() function of the Linux kernel handled the groupinfo reference counter. A local,unprivileged user could use this flaw to crash the system or, potentially,escalate their privileges on the system. (CVE-2014-2851, Important) Use-after-free and information leak flaws were found in the way the Linux kernel's floppy driver processed the FDRAWCMD IOCTL command. A localuser with write access to /dev/fdX could use these flaws to escalate theirprivileges on the system. (CVE-2014-1737, CVE-2014-1738, Important) It was found that the aioreadeventsring() function of the Linux kernel's Asynchronous I/O (AIO) subsystem did not properly sanitize the AIOring head received from user space. A local, unprivileged user could usethis flaw to disclose random parts of the (physical) memory belonging tothe kernel and/or other processes. (CVE-2014-0206, Moderate) An out-of-bounds memory access flaw was found in the Netlink Attribute extension of the Berkeley Packet Filter (BPF) interpreter functionality inthe Linux kernel's networking implementation. A local, unprivileged usercould use this flaw to crash the system or leak kernel memory to user spacevia a specially crafted socket filter. (CVE-2014-3144, CVE-2014-3145,Moderate) An information leak flaw was found in the way the skbzerocopy() function copied socket buffers (skb) that are backed by user-space buffers (forexample vhost-net and Xen netback), potentially allowing an attacker toread data from those buffers. (CVE-2014-2568, Low)Red Hat would like to thank Kees Cook of Google for reportingCVE-2014-3153 and Matthew Daley for reporting CVE-2014-1737 and CVE-2014-1738.Google acknowledges Pinkie Pie as the original reporter ofCVE-2014-3153. The CVE-2014-0206 issue was discovered by Mateusz Guzik ofRed Hat.This update also fixes the following bugs: Due to incorrect calculation of Tx statistics in the qlcninc driver, running the "ethtool -S ethX" command could trigger memory corruption.As a consequence, running the sosreport tool, that uses this command,resulted in a kernel panic. The problem has been fixed by correcting thesaid statistics calculation. (BZ#1104972) When an attempt to create a file on the GFS2 file system failed due to a file system quota violation, the relevant VFS inode was not completelyuninitialized. This could result in a list corruption error. This updateresolves this problem by correctly uninitializing the VFS inode in thissituation. (BZ#1097407) Due to a race condition in the kernel, the getcwd() system call could return "/" instead of the correct full path name when querying a path nameof a file or directory. Paths returned in the "/proc" file system couldalso be incorrect. This problem was causing instability of variousapplications. The aforementioned race condition has been fixed and getcwd()now always returns the correct paths. (BZ#1099048)In addition, this update adds the following enhancements: The kernel mutex code has been improved. The changes include improved queuing of the MCS spin locks, the MCS code optimization, introduction ofthe cancellable MCS spin locks, and improved handling of mutexes withoutwait locks. (BZ#1103631, BZ#1103629) The handling of the Virtual Memory Area (VMA) cache and huge page faults has been improved. (BZ#1103630)All kernel users are advised to upgrade to these updated packages, whichcontain backported patches to correct these issues and add theseenhancements. The system must be rebooted for this update to take effect.