Issued:
2018-01-04
Updated:
2018-01-04

RHSA-2018:0022 - Security Advisory

Synopsis

Important: kernel security update

Type/Severity

Security Advisory: Important

Topic

An update for kernel is now available for Red Hat Enterprise Linux 6.5 Advanced Update Support.

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.

Description

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 instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited.

Note: This issue is present in hardware and cannot be fully fixed via software update. The updated kernel packages provide software mitigation for this hardware issue at a cost of potential performance penalty. Please refer to References section for further information about this issue and the performance impact.

In this update mitigations for x86-64 architecture are provided.

Variant CVE-2017-5753 triggers the speculative execution by performing a bounds-check bypass. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation 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 cross the syscall boundary and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5753, Important)

Variant CVE-2017-5715 triggers the speculative execution by utilizing branch target injection. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation 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 cross the syscall and guest/host boundaries and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5715, Important)

Variant CVE-2017-5754 relies on the fact that, on impacted microprocessors, during speculative execution of instruction permission faults, exception generation triggered by a faulting access is suppressed until the retirement of the whole instruction block. In a combination with the fact that memory accesses may populate the cache even when the block is being dropped and never committed (executed), an unprivileged local attacker could use this flaw to read privileged (kernel space) memory by conducting targeted cache side-channel attacks. (CVE-2017-5754, Important)

Note: CVE-2017-5754 affects Intel x86-64 microprocessors. AMD x86-64 microprocessors are not affected by this issue.

Red Hat would like to thank Google Project Zero for reporting these issues.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

  • Red Hat Enterprise Linux Server - AUS 6.5 x86_64

Fixes

  • BZ - 1519778 - CVE-2017-5753 hw: cpu: speculative execution bounds-check bypass
  • BZ - 1519780 - CVE-2017-5715 hw: cpu: speculative execution branch target injection
  • BZ - 1519781 - CVE-2017-5754 hw: cpu: speculative execution permission faults handling

CVEs

(none)

References

Red Hat Enterprise Linux Server - AUS 6.5

SRPM
kernel-2.6.32-431.85.2.el6.src.rpm SHA-256: 3707f1a124514a17c4fa66843c78a1de77d091f787e2ff162f4748c7f9b81056
x86_64
kernel-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: a2fa63d6020cd613814ba09fb0ce5d78ca02356e1f5613b19f4a6413db8c8f32
kernel-abi-whitelists-2.6.32-431.85.2.el6.noarch.rpm SHA-256: d4610ec85530701ffd2262ccdd9ef591bb2bd6d062af317dca004b434ababbda
kernel-debug-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: a9c014a2f5c0b5521c682d39d4324be48265b1755c2756b10548c6192a4530f9
kernel-debug-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 23801208d410e7d105a1209157fcbb59b3d5fed00d43a892c8e7313d21c73bad
kernel-debug-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 23801208d410e7d105a1209157fcbb59b3d5fed00d43a892c8e7313d21c73bad
kernel-debug-devel-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 4f10b09cd8df0ecf757044bf01947f0c8d429a88e5edde62433f1a013b0e9689
kernel-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: adaf18c4ccb98e09fcfe365436c9beebdf36a8a405be8c7cd8b1ef0d8f267b68
kernel-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: adaf18c4ccb98e09fcfe365436c9beebdf36a8a405be8c7cd8b1ef0d8f267b68
kernel-debuginfo-common-x86_64-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 797de605bad716ca89c34e31b45d652acce470b3e5a5e11ef45c0ab17e3af831
kernel-debuginfo-common-x86_64-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 797de605bad716ca89c34e31b45d652acce470b3e5a5e11ef45c0ab17e3af831
kernel-devel-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 9cf2d9ed41f32663bbbaa10e54d8914a864d361af6115294d992a0564dc590d3
kernel-doc-2.6.32-431.85.2.el6.noarch.rpm SHA-256: 136413557a287ad1079f58393d7729be5e6b082323772b4acdae99b407690577
kernel-firmware-2.6.32-431.85.2.el6.noarch.rpm SHA-256: b25a0371c05d8a72ff7f5692a0d37caa2b3892b8b655992474d4847f5bbdc788
kernel-headers-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 3204e5b4f34279cad060f2039129610446965a7035966d3fdf7821d9c3bf7704
perf-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 056dfbb3f0c968da8469a5c47de3aabb65e4dcab111f4f95a48e00bbd0ef738a
perf-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 378b6cc4dbd4e0d4a20be6bed16fad581d2bf0c96097362bf73c784656d536a0
perf-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 378b6cc4dbd4e0d4a20be6bed16fad581d2bf0c96097362bf73c784656d536a0
python-perf-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 44c0c3da6de4c22e229a2d4503a03b6d30d690f5b8f4f9b8a5bd38a896186617
python-perf-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 9806fac9339aba6e6867afbe435e1fb66a699f99e48f89c40906fed0e23e941c
python-perf-debuginfo-2.6.32-431.85.2.el6.x86_64.rpm SHA-256: 9806fac9339aba6e6867afbe435e1fb66a699f99e48f89c40906fed0e23e941c

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