RHSA-2014:0740: 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 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. A NULL pointer dereference flaw was found in the rdsibladdrcheck() function in the Linux kernel's implementation of Reliable Datagram Sockets(RDS). A local, unprivileged user could use this flaw to crash the system.(CVE-2013-7339, Moderate)Red Hat would like to thank Matthew Daley for reporting CVE-2014-1737 andCVE-2014-1738.This update also fixes the following bugs: A bug in the futex system call could result in an overflow when passing a very large positive timeout. As a consequence, the FUTEXWAIT operationdid not work as intended and the system call was timing out immediately.A backported patch fixes this bug by limiting very large positive timeoutsto the maximal supported value. (BZ#1091832) A new Linux Security Module (LSM) functionality related to the setrlimit hooks should produce a warning message when used by a third party modulethat could not cope with it. However, due to a programming error, thekernel could print this warning message when a process was setting rlimitsfor a different process, or if rlimits were modified by another than themain thread even though there was no incompatible third party module. Thisupdate fixes the relevant code and ensures that the kernel handles thiswarning message correctly. (BZ#1092869) Previously, the kernel was unable to detect KVM on system boot if the Hyper-V emulation was enabled. A patch has been applied to ensure thatboth KVM and Hyper-V hypervisors are now correctly detected during systemboot. (BZ#1094152) A function in the RPC code responsible for verifying whether cached credentials match the current process did not perform the check correctly.The code checked only whether the groups in the current processcredentials appear in the same order as in the cached credentials but didnot ensure that no other groups are present in the cached credentials. Asa consequence, when accessing files in NFS mounts, a process with the sameUID and GID as the original process but with a non-matching group listcould have been granted an unauthorized access to a file, or under certaincircumstances, the process could have been wrongly prevented fromaccessing the file. The incorrect test condition has been fixed and theproblem can no longer occur. (BZ#1095062) When being under heavy load, some Fibre Channel storage devices, such as Hitachi and HP Open-V series, can send a logout (LOGO) message to thehost system. However, due to a bug in the lpfc driver, this could resultin a loss of active paths to the storage and the paths could not berecovered without manual intervention. This update corrects the lpfcdriver to ensure automatic recovery of the lost paths to the storage inthis scenario. (BZ#1096061)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.