RHSA-2017:0932: Important: kernel-rt security and bug fix update

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.<br>Security Fix(es):<br><li> A race condition flaw was found in the NHLDC Linux kernel driver when accessing nhdlc.tbuf list that can lead to double free. A local, unprivileged user able to set the HDLC line discipline on the tty device could use this flaw to increase their privileges on the system. (CVE-2017-2636, Important)</li> <li> A use-after-free flaw was found in the way the Linux kernel's Datagram Congestion Control Protocol (DCCP) implementation freed SKB (socket buffer) resources for a DCCPPKTREQUEST packet when the IPV6RECVPKTINFO option is set on the socket. A local, unprivileged user could use this flaw to alter the kernel memory, allowing them to escalate their privileges on the system. (CVE-2017-6074, Important)</li> <li> A flaw was found in the Linux kernel key management subsystem in which a local attacker could crash the kernel or corrupt the stack and additional memory (denial of service) by supplying a specially crafted RSA key. This flaw panics the machine during the verification of the RSA key. (CVE-2016-8650, Moderate)</li> <li> A flaw was found in the Linux kernel's implementation of setsockopt for the SO{SND|RCV}BUFFORCE setsockopt() system call. Users with non-namespace CAPNETADMIN are able to trigger this call and create a situation in which the sockets sendbuff data size could be negative. This could adversely affect memory allocations and create situations where the system could crash or cause memory corruption. (CVE-2016-9793, Moderate)</li> <li> A flaw was found in the Linux kernel's handling of clearing SELinux attributes on /proc/pid/attr files. An empty (null) write to this file can crash the system by causing the system to attempt to access unmapped kernel memory. (CVE-2017-2618, Moderate)</li> Red Hat would like to thank Alexander Popov for reporting CVE-2017-2636; Andrey Konovalov (Google) for reporting CVE-2017-6074; and Ralf Spenneberg for reporting CVE-2016-8650. The CVE-2017-2618 issue was discovered by Paul Moore (Red Hat Engineering).<br>Bug Fix(es):<br><li> The kernel-rt packages have been upgraded to version 3.10.0-514.rt56.219, which provides a number of bug fix updates over the previous version. (BZ#1429613)</li>