RHSA-2015:1977 - Security Advisory

Topic

Updated kernel-rt packages that fix two security issues, several bugs, and
add one enhancement are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Description

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

• A flaw was found in the way the Linux kernel's VFS subsystem handled file

system locks. A local, unprivileged user could use this flaw to trigger a
deadlock in the kernel, causing a denial of service on the system.
(CVE-2014-8559, Moderate)

• A buffer overflow flaw was found in the way the Linux kernel's virtio-net

subsystem handled certain fraglists when the GRO (Generic Receive Offload)
functionality was enabled in a bridged network configuration. An attacker
on the local network could potentially use this flaw to crash the system,
or, although unlikely, elevate their privileges on the system.
(CVE-2015-5156, Moderate)

The CVE-2015-5156 issue was discovered by Jason Wang of Red Hat.

The kernel-rt packages have been upgraded to version 3.10.0-229.20.1, which
provides a number of bug fixes and enhancements over the previous version,
including:

• Unexpected completion is detected on Intel Ethernet x540
• Divide by zero error in intel_pstate_timer_func() [ inline s64

div_s64_rem() ]

• NFS Recover from stateid-type error on SETATTR
• pNFS RHEL 7.1 Data Server connection remains after umount due to lseg

refcount leak

• Race during NFS v4.0 recovery and standard IO.
• Fix ip6t_SYNPROXY for namespaces and connection delay
• synproxy window size and sequence number behaviour causes long connection

delay

• Crash in kmem_cache_alloc() during disk stress testing (using ipr)
• xfs: sync/backport to upstream v4.1
• iscsi_session recovery_tmo revert back to default when a path becomes

active

• read from MD raid1 can fail if read from resync target fails
• backport scsi-mq
• unable to handle kernel paging request at 0000000000237037 [zswap]

(BZ#1266915)

All kernel-rt users are advised to upgrade to these updated packages, which
correct these issues and add this enhancement. The system must be rebooted
for this update to take effect.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

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

Affected Products

• Red Hat Enterprise Linux for Real Time 7 x86_64
• Red Hat Enterprise Linux for Real Time for x86_64 - Extended Life Cycle Support 7 x86_64

Fixes

• BZ - 1159313 - CVE-2014-8559 kernel: fs: deadlock due to incorrect usage of rename_lock
• BZ - 1243852 - CVE-2015-5156 kernel: buffer overflow with fraglist larger than MAX_SKB_FRAGS + 2 in virtio-net
• BZ - 1266915 - kernel-rt: update to the RHEL7.1.z batch 6 source tree

CVEs

• CVE-2014-8559
• CVE-2015-5156

References

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