Synopsis

Important: kernel security update

Type/Severity

Security Advisory: Important

Topic

An update for kernel is now available for Red Hat Enterprise Linux 5 Extended Lifecycle 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 IBM zSeries (S390) and x86-64 architectures 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, S390 and x86-64)
  
• 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, S390)
  
• 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, x86-64)
  

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 - Extended Life Cycle Support 5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 5 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 5 s390x

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

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/vulnerabilities/speculativeexecution
• https://access.redhat.com/security/cve/CVE-2017-5753
• https://access.redhat.com/security/cve/CVE-2017-5715
• https://access.redhat.com/security/cve/CVE-2017-5754

Red Hat Enterprise Linux Server - Extended Life Cycle Support 5

SRPM
kernel-2.6.18-426.el5.src.rpm	SHA-256: a8059a730ca22b16c6692a490ed1ef57a51861f6f358defcf787f2e77736aa2d
x86_64
kernel-2.6.18-426.el5.x86_64.rpm	SHA-256: 92a13f034930c4a41e4072b969253c04a91b9cb9f17ea257c1cf73e1ee88ab40
kernel-debug-2.6.18-426.el5.x86_64.rpm	SHA-256: 0413dbb814087247a9ca4da3b400f697f00f29cf27bb8a53edcff21f9465c6cc
kernel-debug-debuginfo-2.6.18-426.el5.x86_64.rpm	SHA-256: 206f4aad01f53fa1b350597dc8f4a2b324a5ec4a4a522e480efa628810201aba
kernel-debug-devel-2.6.18-426.el5.x86_64.rpm	SHA-256: dd24bd06fab6a93d0f0efaeb28a8c5317a2ac7cdbb953ee535564ae4b8e4c5b9
kernel-debuginfo-2.6.18-426.el5.x86_64.rpm	SHA-256: 528b7ebff52b85ef9135e7ae8d321d4f6d590f319476db8e910db10cc3edce2a
kernel-debuginfo-common-2.6.18-426.el5.x86_64.rpm	SHA-256: 44fca393c4193e6643e47a08bdd9c3916c4132122e8b47839ac12801b2e87f4f
kernel-devel-2.6.18-426.el5.x86_64.rpm	SHA-256: ea489cd9203edaea201795092b7076b78c8853dc0a8e381eb99c7dede731bad8
kernel-doc-2.6.18-426.el5.noarch.rpm	SHA-256: 1f48ec42f29763264771640891eb2e09eccb127ed50d889979164cc5e507b546
kernel-headers-2.6.18-426.el5.x86_64.rpm	SHA-256: 8d06568474f3b3e0bdc19af70a2fc923b982eaf11de6288c95bae0344b8a8e3b
kernel-xen-2.6.18-426.el5.x86_64.rpm	SHA-256: f585c5f0e873c291539ff441e64d009d78cd69c56043ae5fa25d161e49b3fd2b
kernel-xen-debuginfo-2.6.18-426.el5.x86_64.rpm	SHA-256: 87e95fe65abe7247d642c44877b367fab1b2c4a90383b34172b02ffbc009d36f
kernel-xen-devel-2.6.18-426.el5.x86_64.rpm	SHA-256: 556d4a877807217b93cc66cbd1bfac50e0a59a2868298d88634c8d4b79a54b78
i386
kernel-2.6.18-426.el5.i686.rpm	SHA-256: c45d75fe47a3cd099176aac9c83790b83f13e1f54bad5561568adc7c7cc7a544
kernel-PAE-2.6.18-426.el5.i686.rpm	SHA-256: 8b06870acf7403b275fc12f03567659a5a1343d648097de1c2192dfd0f2c915c
kernel-PAE-debuginfo-2.6.18-426.el5.i686.rpm	SHA-256: 959be62fa98b36cafa979ef05059e5a35771fc5605bb5542128b8e757b51d8ed
kernel-PAE-devel-2.6.18-426.el5.i686.rpm	SHA-256: 449ebecb96bb54f13370fc7aff3902bc6e8b5a86c25eb02fbddf23830f74a84a
kernel-debug-2.6.18-426.el5.i686.rpm	SHA-256: dcef0fd6afb1aeafe7241b68e34b8237f04ee5d64bdcf73078d1f1b7bff68bb7
kernel-debug-debuginfo-2.6.18-426.el5.i686.rpm	SHA-256: 19e93c73931e95f2e2a79b3166132936e2c4942d5c8c1436226db764806eef80
kernel-debug-devel-2.6.18-426.el5.i686.rpm	SHA-256: c8734cf284255999fc1dff1cd79f691acf82f57962c330f344d0573a6a9b97a5
kernel-debuginfo-2.6.18-426.el5.i686.rpm	SHA-256: 302d43695d30aaf706f97c0a5e1af1e63a41d26ee4ecbf58a44996b2cf82f5de
kernel-debuginfo-common-2.6.18-426.el5.i686.rpm	SHA-256: 00fc6dd916736abb45115f6ff5c9f1d12a7e866f44ac61f53102decd28ff835d
kernel-devel-2.6.18-426.el5.i686.rpm	SHA-256: 18c575fc1918f14d90a8f2eaa12ae15118b698e18dcf5a29b0f0e1f34d52a54a
kernel-doc-2.6.18-426.el5.noarch.rpm	SHA-256: 1f48ec42f29763264771640891eb2e09eccb127ed50d889979164cc5e507b546
kernel-headers-2.6.18-426.el5.i386.rpm	SHA-256: dca7b81790b8fe556fd8a85c94cfbaef4b47263cf06106cd714136a202e45f9f
kernel-xen-2.6.18-426.el5.i686.rpm	SHA-256: bc20418bef51db0b25da66a5dd51aa8e45a11d315e35548b00e638418c70a33c
kernel-xen-debuginfo-2.6.18-426.el5.i686.rpm	SHA-256: f8ad1748d5d194d2e1e077826bf39e3f023d9a9cb72e3ded49bde80fe35886bb
kernel-xen-devel-2.6.18-426.el5.i686.rpm	SHA-256: 89b01adbe85b31f008e26b4137318af1c1685834f7b0ef6760a66d9ca85a7ac6

Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 5

SRPM
kernel-2.6.18-426.el5.src.rpm	SHA-256: a8059a730ca22b16c6692a490ed1ef57a51861f6f358defcf787f2e77736aa2d
s390x
kernel-2.6.18-426.el5.s390x.rpm	SHA-256: 5c2c0a040ba0fe3915bc09ad741b9c3f26e9fa143efd4fce025552d37b5d6c77
kernel-debug-2.6.18-426.el5.s390x.rpm	SHA-256: 149d0670b8ddbacaa6f3633347781eed74959a601828da6d604787b1b6658e22
kernel-debug-debuginfo-2.6.18-426.el5.s390x.rpm	SHA-256: 1305de3943f514ab1b9e35e0b1715e2a25794a0c691864eb60c63a0b022dcecc
kernel-debug-devel-2.6.18-426.el5.s390x.rpm	SHA-256: e4eed630c3cdc88f47c830489654f5037ef02320baa75f3dd47f52fc4251a986
kernel-debuginfo-2.6.18-426.el5.s390x.rpm	SHA-256: 77f1574a1088c1413004a1da0abda3ac73a76d8c84cc59dae4a5fbd60fd11369
kernel-debuginfo-common-2.6.18-426.el5.s390x.rpm	SHA-256: 651f02bb944f5813b29b048b10757e1d6fdffc0a63e3fc0796f5c5520f23df43
kernel-devel-2.6.18-426.el5.s390x.rpm	SHA-256: 7dc59bbe8e7fd12b133f0957332a63117c970779efbfffd5aa3250a7aa0b0608
kernel-doc-2.6.18-426.el5.noarch.rpm	SHA-256: 1f48ec42f29763264771640891eb2e09eccb127ed50d889979164cc5e507b546
kernel-headers-2.6.18-426.el5.s390x.rpm	SHA-256: 0fad6d51c9d7d7237fd346ee70e4df08c94d17e5c3e240fd8b3ed1420f4e5f92
kernel-kdump-2.6.18-426.el5.s390x.rpm	SHA-256: b2e21c76cc6a742adafef409abb8d4dc1b1545ae36759d28c10a6b63d02e8a32
kernel-kdump-debuginfo-2.6.18-426.el5.s390x.rpm	SHA-256: 8c9612695e36b6d950079d558323e10bac5c3c922dea0ccc02518e56c4884347
kernel-kdump-devel-2.6.18-426.el5.s390x.rpm	SHA-256: e99e67490d2db77d8c5be9cc86d8b66882d023f463eb3383e938b44d761409ae