(RHSA-2016:1847) Important: kernel security, bug fix, and enhancement update

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

Security Fix(es):

• A security flaw was found in the Linux kernel in the mark_source_chains() function in “net/ipv4/netfilter/ip_tables.c”. It is possible for a user-supplied “ipt_entry” structure to have a large “next_offset” field. This field is not bounds checked prior to writing to a counter value at the supplied offset. (CVE-2016-3134, Important)

• A flaw was discovered in processing setsockopt for 32 bit processes on 64 bit systems. This flaw will allow attackers to alter arbitrary kernel memory when unloading a kernel module. This action is usually restricted to root-privileged users but can also be leveraged if the kernel is compiled with CONFIG_USER_NS and CONFIG_NET_NS and the user is granted elevated privileges. (CVE-2016-4997, Important)

• An out-of-bounds heap memory access leading to a Denial of Service, heap disclosure, or further impact was found in setsockopt(). The function call is normally restricted to root, however some processes with cap_sys_admin may also be able to trigger this flaw in privileged container environments. (CVE-2016-4998, Moderate)

Bug Fix(es):

• In some cases, running the ipmitool command caused a kernel panic due to a race condition in the ipmi message handler. This update fixes the race condition, and the kernel panic no longer occurs in the described scenario. (BZ#1353947)

• Previously, running I/O-intensive operations in some cases caused the system to terminate unexpectedly after a null pointer dereference in the kernel. With this update, a set of patches has been applied to the 3w-9xxx and 3w-sas drivers that fix this bug. As a result, the system no longer crashes in the described scenario. (BZ#1362040)

• Previously, the Stream Control Transmission Protocol (SCTP) sockets did not inherit the SELinux labels properly. As a consequence, the sockets were labeled with the unlabeled_t SELinux type which caused SCTP connections to fail. The underlying source code has been modified, and SCTP connections now works as expected. (BZ#1354302)

• Previously, the bnx2x driver waited for transmission completions when recovering from a parity event, which substantially increased the recovery time. With this update, bnx2x does not wait for transmission completion in the described circumstances. As a result, the recovery of bnx2x after a parity event now takes less time. (BZ#1351972)

Enhancement(s):

• With this update, the audit subsystem enables filtering of processes by name besides filtering by PID. Users can now audit by executable name (with the “-F exe=<path-to-executable>” option), which allows expression of many new audit rules. This functionality can be used to create events when specific applications perform a syscall. (BZ#1345774)

• With this update, the Nonvolatile Memory Express (NVMe) and the multi-queue block layer (blk_mq) have been upgraded to the Linux 4.5 upstream version. Previously, a race condition between timeout and freeing request in blk_mq occurred, which could affect the blk_mq_tag_to_rq() function and consequently a kernel oops could occur. The provided patch fixes this race condition by updating the tags with the active request. The patch simplifies blk_mq_tag_to_rq() and ensures that the two requests are not active at the same time. (BZ#1350352)

• The Hyper-V storage driver (storvsc) has been upgraded from upstream. This update provides moderate performance improvement of I/O operations when using storvscr for certain workloads. (BZ#1360161)

Additional Changes:

Space precludes documenting all of the bug fixes and enhancements included in this advisory. To see the complete list of bug fixes and enhancements, refer to the following KnowledgeBase article: https://access.redhat.com/articles/2592321