RHSA-2016:0855: Moderate: kernel security, bug fix, and enhancement update

First published: Tue May 10 2016(Updated: )

The kernel packages contain the Linux kernel, the core of any Linux operating system.<br>Security Fix(es):<br><li> It was found that reporting emulation failures to user space could lead to either a local (CVE-2014-7842) or a L2-&gt;L1 (CVE-2010-5313) denial of service. In the case of a local denial of service, an attacker must have access to the MMIO area or be able to access an I/O port. Please note that on certain systems, HPET is mapped to userspace as part of vdso (vvar) and thus an unprivileged user may generate MMIO transactions (and enter the emulator) this way. (CVE-2010-5313, CVE-2014-7842, Moderate)</li> <li> It was found that the Linux kernel did not properly account file descriptors passed over the unix socket against the process limit. A local user could use this flaw to exhaust all available memory on the system. (CVE-2013-4312, Moderate)</li> <li> A buffer overflow flaw was found in the way the Linux kernel's virtio-net subsystem handled certain fraglists when the GRO (Generic Receive Offload) functionality was enabled in a bridged network configuration. An attacker on the local network could potentially use this flaw to crash the system, or, although unlikely, elevate their privileges on the system. (CVE-2015-5156, Moderate)</li> <li> It was found that the Linux kernel's IPv6 network stack did not properly validate the value of the MTU variable when it was set. A remote attacker could potentially use this flaw to disrupt a target system's networking (packet loss) by setting an invalid MTU value, for example, via a NetworkManager daemon that is processing router advertisement packets running on the target system. (CVE-2015-8215, Moderate)</li> <li> A NULL pointer dereference flaw was found in the way the Linux kernel's network subsystem handled socket creation with an invalid protocol identifier. A local user could use this flaw to crash the system. (CVE-2015-8543, Moderate)</li> <li> It was found that the espfix functionality does not work for 32-bit KVM paravirtualized guests. A local, unprivileged guest user could potentially use this flaw to leak kernel stack addresses. (CVE-2014-8134, Low)</li> <li> A flaw was found in the way the Linux kernel's ext4 file system driver handled non-journal file systems with an orphan list. An attacker with physical access to the system could use this flaw to crash the system or, although unlikely, escalate their privileges on the system. (CVE-2015-7509, Low)</li> <li> A NULL pointer dereference flaw was found in the way the Linux kernel's ext4 file system driver handled certain corrupted file system images. An attacker with physical access to the system could use this flaw to crash the system. (CVE-2015-8324, Low)</li> Red Hat would like to thank Nadav Amit for reporting CVE-2010-5313 and CVE-2014-7842, Andy Lutomirski for reporting CVE-2014-8134, and Dmitriy Monakhov (OpenVZ) for reporting CVE-2015-8324. The CVE-2015-5156 issue was discovered by Jason Wang (Red Hat).<br>Additional Changes:<br><li> Refer to Red Hat Enterprise Linux 6.8 Release Notes for information on new kernel features and known issues, and Red Hat Enterprise Linux Technical Notes for information on device driver updates, important changes to external kernel parameters, notable bug fixes, and technology previews. Both of these documents are linked to in the References section.</li>

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