7.2 - RHSA-2014:0786

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Client Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Server (v. 7) - noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 7) - noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 7) - noarch, x86_64

3. 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.

4. 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.

5. Bugs fixed (https://bugzilla.redhat.com/):

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