(RHSA-2018:2164) Important: kernel security and bug fix update

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

Security Fix(es):

• An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of Load & Store instructions (a commonly used performance optimization). It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory read from address to which a recent memory write has occurred may see an older value and subsequently cause an update into the microprocessor’s data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to read privileged memory by conducting targeted cache side-channel attacks. (CVE-2018-3639, x86 AMD)

• kernel: Use-after-free vulnerability in mm/mempolicy.c:do_get_mempolicy function allows local denial of service or other unspecified impact (CVE-2018-10675)

• Kernel: FPU state information leakage via lazy FPU restore (CVE-2018-3665)

• kernel: error in exception handling leads to DoS (CVE-2018-8897 regression) (CVE-2018-10872)

For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section.

Red Hat would like to thank Ken Johnson (Microsoft Security Response Center) and Jann Horn (Google Project Zero) for reporting CVE-2018-3639 and Julian Stecklina (Amazon.de), Thomas Prescher (cyberus-technology.de), and Zdenek Sojka (sysgo.com) for reporting CVE-2018-3665.

Bug Fix(es):

• Previously, microcode updates on 32 and 64-bit AMD and Intel architectures were not synchronized. As a consequence, it was not possible to apply the microcode updates. This fix adds the synchronization to the microcode updates so that processors of the stated architectures receive updates at the same time. As a result, microcode updates are now synchronized. (BZ#1574592)