RHSA-2018:0512: Red Hat Security Advisory: kernel security and bug fix update

An update for kernel is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es):

• hw: cpu: speculative execution branch target injection (s390-only) (CVE-2017-5715, Important)
• hw: cpu: speculative execution bounds-check bypass (s390 and powerpc) (CVE-2017-5753, Important)
• hw: cpu: speculative execution permission faults handling (powerpc-only) (CVE-2017-5754) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. Bug Fixes:
• If a fibre channel (FC) switch was powered down and then powered on again, the SCSI device driver stopped permanently the SCSI device’s request queue. Consequently, the FC port login failed, leaving the port state as “Bypassed” instead of "Online", and users had to reboot the operating system. This update fixes the driver to avoid the permanent stop of the request queue. As a result, SCSI device now continues working as expected after power cycling the FC switch. (BZ#1519857)
• Previously, on final close or unlink of a file, the find_get_pages() function in the memory management sometimes found no pages even if there were some pages left to save. Consequently, a kernel crash occurred when attempting to enter the unlink() function. This update fixes the find_get_pages() function in the memory management code to not return 0 too early. As a result, the kernel no longer crashes due to this behavior.(BZ#1527811)
• Using IPsec connections under a heavy load could previously lead to a network performance degradation, especially when using the aesni-intel module. This update fixes the issue by making the cryptd queue length configurable so that it can be increased to prevent an overflow and packet drop. As a result, using IPsec under a heavy load no longer reduces network performance. (BZ#1527802)
• Previously, a deadlock in the bnx2fc driver caused all adapters to block and the SCSI error handler to become unresponsive. As a result, data transferring through the adapter was sometimes blocked. This update fixes bnx2fc, and data transferring through the adapter is no longer blocked due to this behavior. (BZ#1523783)
• If an NFSv3 client mounted a subdirectory of an exported file system, a directory entry to the mount hosting the export was incorrectly held even after clearing the cache. Consequently, attempts to unmount the subdirectory with the umount command failed with the EBUSY error. With this update, the underlying source code has been fixed, and the unmount operation now succeeds as expected in the described situation. (BZ#1535938) Users of kernel are advised to upgrade to these updated packages, which fix these bugs. The system must be rebooted for this update to take effect. Related CVEs:
• CVE-2017-5753: hw: cpu: speculative execution bounds-check bypass