(RHSA-2016:2128) Important: kernel security and enhancement update

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

• A flaw was found in the Linux kernel’s keyring handling code: the key_reject_and_link() function could be forced to free an arbitrary memory block. An attacker could use this flaw to trigger a use-after-free condition on the system, potentially allowing for privilege escalation. (CVE-2016-4470, Important)

• A race condition was found in the way the Linux kernel’s memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged, local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system. (CVE-2016-5195, Important)

Red Hat would like to thank Phil Oester for reporting CVE-2016-5195. The CVE-2016-4470 issue was discovered by David Howells (Red Hat).

Enhancement(s):

• This update fixes a tape write problem by fixing the use of the sas_is_tlr_enabled API in the mpt3sas driver. The driver now checks whether Transport Layer Recovery (TLR) is enabled before enabling the MPI2_SCSIIO_CONTROL_TLR_ON flag. (BZ#1372352)