Synopsis

Important: kernel security, bug fix, and enhancement update

Type/Severity

Security Advisory: Important

Topic

Updated kernel packages that fix multiple security issues, several bugs,
and add various enhancements are now available for Red Hat Enterprise
Linux 7.

The Red Hat Security Response Team has rated this update as having
Important 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 futex subsystem handled

the requeuing of certain Priority Inheritance (PI) futexes. A local,
unprivileged user could use this flaw to escalate their privileges on the
system. (CVE-2014-3153, Important)

• A use-after-free flaw was found in the way the ping_init_sock() function

of the Linux kernel handled the group_info reference counter. A local,
unprivileged user could use this flaw to crash the system or, potentially,
escalate their privileges on the system. (CVE-2014-2851, Important)

• Use-after-free and information leak flaws were found in the way the

Linux kernel's floppy driver processed the FDRAWCMD IOCTL command. A local
user with write access to /dev/fdX could use these flaws to escalate their
privileges on the system. (CVE-2014-1737, CVE-2014-1738, Important)

• It was found that the aio_read_events_ring() function of the Linux

kernel's Asynchronous I/O (AIO) subsystem did not properly sanitize the AIO
ring head received from user space. A local, unprivileged user could use
this flaw to disclose random parts of the (physical) memory belonging to
the kernel and/or other processes. (CVE-2014-0206, Moderate)

• An out-of-bounds memory access flaw was found in the Netlink Attribute

extension of the Berkeley Packet Filter (BPF) interpreter functionality in
the Linux kernel's networking implementation. A local, unprivileged user
could use this flaw to crash the system or leak kernel memory to user space
via a specially crafted socket filter. (CVE-2014-3144, CVE-2014-3145,
Moderate)

• An information leak flaw was found in the way the skb_zerocopy() function

copied socket buffers (skb) that are backed by user-space buffers (for
example vhost-net and Xen netback), potentially allowing an attacker to
read data from those buffers. (CVE-2014-2568, Low)

Red Hat would like to thank Kees Cook of Google for reporting
CVE-2014-3153 and Matthew Daley for reporting CVE-2014-1737 and CVE-2014-1738.
Google acknowledges Pinkie Pie as the original reporter of
CVE-2014-3153. The CVE-2014-0206 issue was discovered by Mateusz Guzik of
Red Hat.

This update also fixes the following bugs:

• Due to incorrect calculation of Tx statistics in the qlcninc driver,

running the "ethtool -S ethX" command could trigger memory corruption.
As a consequence, running the sosreport tool, that uses this command,
resulted in a kernel panic. The problem has been fixed by correcting the
said statistics calculation. (BZ#1104972)

• When an attempt to create a file on the GFS2 file system failed due to a

file system quota violation, the relevant VFS inode was not completely
uninitialized. This could result in a list corruption error. This update
resolves this problem by correctly uninitializing the VFS inode in this
situation. (BZ#1097407)

• Due to a race condition in the kernel, the getcwd() system call could

return "/" instead of the correct full path name when querying a path name
of a file or directory. Paths returned in the "/proc" file system could
also be incorrect. This problem was causing instability of various
applications. The aforementioned race condition has been fixed and getcwd()
now always returns the correct paths. (BZ#1099048)

In addition, this update adds the following enhancements:

• The kernel mutex code has been improved. The changes include improved

queuing of the MCS spin locks, the MCS code optimization, introduction of
the cancellable MCS spin locks, and improved handling of mutexes without
wait locks. (BZ#1103631, BZ#1103629)

• The handling of the Virtual Memory Area (VMA) cache and huge page faults

has been improved. (BZ#1103630)

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add these
enhancements. 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.

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/site/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do not use
"rpm -Uvh" as that will remove the running kernel binaries from your
system. You may use "rpm -e" to remove old kernels after determining that
the new kernel functions properly on your system.

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - 1079012 - CVE-2014-2568 kernel: net: potential information leak when ubuf backed skbs are skb_zerocopy()ied
• BZ - 1086730 - CVE-2014-2851 kernel: net: ping: refcount issue in ping_init_sock() function
• BZ - 1094299 - CVE-2014-1737 CVE-2014-1738 kernel: block: floppy: privilege escalation via FDRAWCMD floppy ioctl command
• BZ - 1094602 - CVE-2014-0206 kernel: aio: insufficient sanitization of head in aio_read_events_ring()
• BZ - 1096775 - CVE-2014-3144 CVE-2014-3145 Kernel: filter: prevent nla extensions to peek beyond the end of the message
• BZ - 1103626 - CVE-2014-3153 kernel: futex: pi futexes requeue issue

CVEs

• CVE-2014-1737
• CVE-2014-2851
• CVE-2014-1738
• CVE-2014-3153
• CVE-2014-2568
• CVE-2014-3144
• CVE-2014-0206
• CVE-2014-3145

References