RHSA-2015:1221: Moderate: kernel security, bug fix, and enhancement update

The kernel packages contain the Linux kernel, the core of any Linuxoperating system. A NULL pointer dereference flaw was found in the way the Linux kernel's virtual console implementation handled reference counting when accessingpseudo-terminal device files (/dev/pts/). A local, unprivileged attackercould use this flaw to crash the system. (CVE-2011-5321, Moderate) It was found that the Linux kernel's ping socket implementation did not properly handle socket unhashing during spurious disconnects, which couldlead to a use-after-free flaw. On x86-64 architecture systems, a local userable to create ping sockets could use this flaw to crash the system.On non-x86-64 architecture systems, a local user able to create pingsockets could use this flaw to escalate their privileges on the system.(CVE-2015-3636, Moderate) An integer overflow flaw was found in the way the Linux kernel randomized the stack for processes on certain 64-bit architecture systems, such asx86-64, causing the stack entropy to be reduced by four. (CVE-2015-1593,Low) A flaw was found in the way the Linux kernel's 32-bit emulation implementation handled forking or closing of a task with an 'int80' entry.A local user could potentially use this flaw to escalate their privilegeson the system. (CVE-2015-2830, Low) It was found that the Linux kernel's TCP/IP protocol suite implementation for IPv6 allowed the Hop Limit value to be set to a smaller value than thedefault one. An attacker on a local network could use this flaw to preventsystems on that network from sending or receiving network packets.(CVE-2015-2922, Low)These updated kernel packages also include numerous bug fixes and oneenhancement. Space precludes documenting all of these changes in thisadvisory. For information on the most significant of these changes, usersare directed to the following article on the Red Hat Customer Portal:https://access.redhat.com/articles/1506133 All kernel users are advised to upgrade to these updated packages, whichcontain backported patches to correct these issues and add thisenhancement. The system must be rebooted for this update to take effect.