RHSA-2015:0864: 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 seunshare, a utility for running executables under a different security context, used the capnglock functionality ofthe libcap-ng library. The subsequent invocation of suid root binaries thatrelied on the fact that the setuid() system call, among others, also setsthe saved set-user-ID when dropping the binaries' process privileges, couldallow a local, unprivileged user to potentially escalate their privilegeson the system. Note: the fix for this issue is the kernel part of theoverall fix, and introduces the PRSETNONEWPRIVS functionality and therelated SELinux exec transitions support. (CVE-2014-3215, Important) A use-after-free flaw was found in the way the Linux kernel's SCTP implementation handled authentication key reference counting during INITcollisions. A remote attacker could use this flaw to crash the system or,potentially, escalate their privileges on the system. (CVE-2015-1421,Important) It was found that the Linux kernel's KVM implementation did not ensure that the host CR4 control register value remained unchanged across VMentries on the same virtual CPU. A local, unprivileged user could use thisflaw to cause a denial of service on the system. (CVE-2014-3690, Moderate) An out-of-bounds memory access flaw was found in the syscall tracing functionality of the Linux kernel's perf subsystem. A local, unprivilegeduser could use this flaw to crash the system. (CVE-2014-7825, Moderate) An out-of-bounds memory access flaw was found in the syscall tracing functionality of the Linux kernel's ftrace subsystem. On a system withftrace syscall tracing enabled, a local, unprivileged user could use thisflaw to crash the system, or escalate their privileges. (CVE-2014-7826,Moderate) It was found that the Linux kernel memory resource controller's (memcg) handling of OOM (out of memory) conditions could lead to deadlocks.An attacker able to continuously spawn new processes within a singlememory-constrained cgroup during an OOM event could use this flaw to lockup the system. (CVE-2014-8171, Moderate) A race condition flaw was found in the way the Linux kernel keys management subsystem performed key garbage collection. A local attackercould attempt accessing a key while it was being garbage collected, whichwould cause the system to crash. (CVE-2014-9529, Moderate) A stack-based buffer overflow flaw was found in the TechnoTrend/Hauppauge DEC USB device driver. A local user with write access to the correspondingdevice could use this flaw to crash the kernel or, potentially, elevatetheir privileges on the system. (CVE-2014-8884, Low) An information leak flaw was found in the way the Linux kernel's ISO9660 file system implementation accessed data on an ISO9660 image with RockRidgeExtension Reference (ER) records. An attacker with physical access to thesystem could use this flaw to disclose up to 255 bytes of kernel memory.(CVE-2014-9584, Low)Red Hat would like to thank Andy Lutomirski for reporting CVE-2014-3215and CVE-2014-3690, Robert Święcki for reporting CVE-2014-7825 andCVE-2014-7826, and Carl Henrik Lunde for reporting CVE-2014-9584. TheCVE-2015-1421 issue was discovered by Sun Baoliang of Red Hat.This update also fixes several bugs. Documentation for these changes isavailable from the Technical Notes document linked to in the Referencessection.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.