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

RHSA-2018:0016 - Security Advisory

Synopsis

Important: kernel-rt security update

Type/Severity

Security Advisory: Important

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 7.

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-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

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 for Real Time 7 x86_64
  • Red Hat Enterprise Linux for Real Time for NFV 7 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 for Real Time 7

SRPM
kernel-rt-3.10.0-693.11.1.rt56.639.el7.src.rpm SHA-256: 3cb81e99cfe60283b397cfcd2a6cfa34fd347a8fc02fde6e95d84259ccfdefc8
x86_64
kernel-rt-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 1271fa5971e176fc6f385be5bd6334c244a2d1cc5ac2dd4e3915abdb4d9d5286
kernel-rt-debug-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 5a8f340a7952c254bb1ae607955efcef146943bb618d2235da9ef78426f05e79
kernel-rt-debug-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 34192cb7f5594b212c8bf0c5346bbaeab8886ae7baecd20be4d049c1fe626554
kernel-rt-debug-devel-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 33aaefad431dd69c2e674f30ac1737984c495cc4f61a05323ad0b0909525aea8
kernel-rt-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: afc1078e57c4909c1a04f2228f6dc2e098c64e69e9b45e7c9a0b958d76833d56
kernel-rt-debuginfo-common-x86_64-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 374abf72da8c5e83096af024178a02fbb80ef0eee5a6d3c9e4eda2004ce708dd
kernel-rt-devel-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 13064fa78bfd773c0e3914ce079d1a1b8a89413a3b83f42f9baaee484a36d79a
kernel-rt-doc-3.10.0-693.11.1.rt56.639.el7.noarch.rpm SHA-256: a7a56d4eba6b8eaa6829522b5d89d95599fe461802fda225c775f64afbf3857b
kernel-rt-trace-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: e1fc5179a67d7ebd4b931421c7ac5ccc4dccb7addeadd4edefd31b803301acb3
kernel-rt-trace-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: fe1117b70baf9a60b1bb6755b771330b9f5c67113e476fde80a54021af103efd
kernel-rt-trace-devel-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 5507280b611f1aa4ea5cc9cd94581b015f48193af4bf239e7fe0c2f2e09b2097

Red Hat Enterprise Linux for Real Time for NFV 7

SRPM
kernel-rt-3.10.0-693.11.1.rt56.639.el7.src.rpm SHA-256: 3cb81e99cfe60283b397cfcd2a6cfa34fd347a8fc02fde6e95d84259ccfdefc8
x86_64
kernel-rt-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 1271fa5971e176fc6f385be5bd6334c244a2d1cc5ac2dd4e3915abdb4d9d5286
kernel-rt-debug-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 5a8f340a7952c254bb1ae607955efcef146943bb618d2235da9ef78426f05e79
kernel-rt-debug-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 34192cb7f5594b212c8bf0c5346bbaeab8886ae7baecd20be4d049c1fe626554
kernel-rt-debug-devel-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 33aaefad431dd69c2e674f30ac1737984c495cc4f61a05323ad0b0909525aea8
kernel-rt-debug-kvm-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 561ec98585a986eec4d39ce8ecf7507890afd6e848fd9f04b67e0f4ed74f66e6
kernel-rt-debug-kvm-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 24009c0ba3baff2f8c0bf16df575b93404639c852c2c372944488f19c07ff92a
kernel-rt-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: afc1078e57c4909c1a04f2228f6dc2e098c64e69e9b45e7c9a0b958d76833d56
kernel-rt-debuginfo-common-x86_64-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 374abf72da8c5e83096af024178a02fbb80ef0eee5a6d3c9e4eda2004ce708dd
kernel-rt-devel-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 13064fa78bfd773c0e3914ce079d1a1b8a89413a3b83f42f9baaee484a36d79a
kernel-rt-doc-3.10.0-693.11.1.rt56.639.el7.noarch.rpm SHA-256: a7a56d4eba6b8eaa6829522b5d89d95599fe461802fda225c775f64afbf3857b
kernel-rt-kvm-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 0d64c770a7999d21735d981b5fd0fad39207c0d1a78a18158ff6115f1cfcdba2
kernel-rt-kvm-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 617904aa2925f170a0960b57f1f51e1f978604c7fcdef5612da57d34f718ffef
kernel-rt-trace-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: e1fc5179a67d7ebd4b931421c7ac5ccc4dccb7addeadd4edefd31b803301acb3
kernel-rt-trace-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: fe1117b70baf9a60b1bb6755b771330b9f5c67113e476fde80a54021af103efd
kernel-rt-trace-devel-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 5507280b611f1aa4ea5cc9cd94581b015f48193af4bf239e7fe0c2f2e09b2097
kernel-rt-trace-kvm-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: dabb7f98f4dc313977c9da7fbc3f3cff858d9e69225e473b7fa6ef351374634a
kernel-rt-trace-kvm-debuginfo-3.10.0-693.11.1.rt56.639.el7.x86_64.rpm SHA-256: 4895ce56a9dde9d562fba23868a0b45a2eb3d3076c19dadb2aa27989ad322e32

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