RHSA-2016:0715 - Security Advisory

Topic

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 Moderate. 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):

• A flaw was found in the way the Linux kernel handled IRET faults during the processing of NMIs. An unprivileged, local user could use this flaw to crash the system or, potentially (although highly unlikely), escalate their privileges on the system. (CVE-2015-5157, Moderate)
• A race condition flaw was found in the way the Linux kernel's SCTP implementation handled sctp_accept() during the processing of heartbeat timeout events. A remote attacker could use this flaw to prevent further connections to be accepted by the SCTP server running on the system, resulting in a denial of service. (CVE-2015-8767, Moderate)

Bug Fix(es):

• When the nvme driver held the queue lock for too long, for example during DMA mapping, a lockup occurred leading to nvme hard-lockup panic. This update fixes the underlying source code, and nvme now works as expected.(BZ#1314209)
• Due to a regression, a Unix domain datagram socket could come to a deadlock when sending a datagram to itself. The provided patch adds another "sk" check to the unix_dgram_sendmsg() function, and the aforementioned deadlock no longer occurs. (BZ#1315696)
• Previously, writing a large file using direct I/O in 16 MB chunks sometimes caused a pathological allocation pattern where 16 MB chunks of large free extent were allocated to a file in reversed order. The provided patch avoids the backward allocation, and writing a large file using direct I/O now proceeds successfully. (BZ#1320031)
• MD RAID1 devices that repeatedly became hot removed and re-added could become mismatched due to a race condition. This caused them to return stale data, leading to data corruption. The provided set of patches fixes this bug, and hot removals and re-additions of md devices now work as expected. (BZ#1320863)
• A couple of previous fixes caused a deadlock on the "rq" lock leading to a kernel panic on CPU 0. The provided set of patches reverts the relevant commits, thus preventing the panic from occurring. (BZ#1326043)

Enhancement(s):

• VLAN support has been updated to integrate some of the latest upstream features. This update also makes sure that Null pointer crashes related to VLAN support in bonding mode no longer occur and that tag stripping and insertion work as expected. (BZ#1315706)
• This update adds additional model numbers for Broadwell to perf. (BZ#1320035)

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 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.7 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.7 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.7 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux for SAP Solutions for x86_64 - Extended Update Support 6.7 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.7 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.7 i386
• Red Hat Enterprise Linux EUS Compute Node 6.7 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 1259577 - CVE-2015-5157 kernel: x86-64: IRET faults during NMIs processing
• BZ - 1297389 - CVE-2015-8767 kernel: SCTP denial of service during timeout

CVEs

• CVE-2015-5157
• CVE-2015-8767

References

• http://www.redhat.com/security/updates/classification/#normal