RHSA-2014:0557 - Security Advisory

Topic

Updated kernel-rt packages that fix multiple security issues are now
available for Red Hat Enterprise MRG 2.5.

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

• A race condition leading to a use-after-free flaw was found in the way

the Linux kernel's TCP/IP protocol suite implementation handled the
addition of fragments to the LRU (Last-Recently Used) list under certain
conditions. A remote attacker could use this flaw to crash the system or,
potentially, escalate their privileges on the system by sending a large
amount of specially crafted fragmented packets to that system.
(CVE-2014-0100, Important)

• A race condition flaw, leading to heap-based buffer overflows, was found

in the way the Linux kernel's N_TTY line discipline (LDISC) implementation
handled concurrent processing of echo output and TTY write operations
originating from user space when the underlying TTY driver was PTY.
An unprivileged, local user could use this flaw to crash the system or,
potentially, escalate their privileges on the system. (CVE-2014-0196,
Important)

• A flaw was found in the way the Linux kernel's floppy driver handled user

space provided data in certain error code paths while processing FDRAWCMD
IOCTL commands. A local user with write access to /dev/fdX could use this
flaw to free (using the kfree() function) arbitrary kernel memory.
(CVE-2014-1737, Important)

• It was found that the Linux kernel's floppy driver leaked internal kernel

memory addresses to user space during the processing of the FDRAWCMD IOCTL
command. A local user with write access to /dev/fdX could use this flaw to
obtain information about the kernel heap arrangement. (CVE-2014-1738, Low)

Note: A local user with write access to /dev/fdX could use these two flaws
(CVE-2014-1737 in combination with CVE-2014-1738) to escalate their
privileges on the system.

• 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)

• It was found that a remote attacker could use a race condition flaw in

the ath_tx_aggr_sleep() function to crash the system by creating large
network traffic on the system's Atheros 9k wireless network adapter.
(CVE-2014-2672, Moderate)

• A NULL pointer dereference flaw was found in the rds_iw_laddr_check()

function in the Linux kernel's implementation of Reliable Datagram Sockets
(RDS). A local, unprivileged user could use this flaw to crash the system.
(CVE-2014-2678, Moderate)

• A race condition flaw was found in the way the Linux kernel's mac80211

subsystem implementation handled synchronization between TX and STA wake-up
code paths. A remote attacker could use this flaw to crash the system.
(CVE-2014-2706, Moderate)

• It was found that the try_to_unmap_cluster() function in the Linux

kernel's Memory Managment subsystem did not properly handle page locking in
certain cases, which could potentially trigger the BUG_ON() macro in the
mlock_vma_page() function. A local, unprivileged user could use this flaw
to crash the system. (CVE-2014-3122, Moderate)

Red Hat would like to thank Matthew Daley for reporting CVE-2014-1737 and
CVE-2014-1738. The CVE-2014-0100 issue was discovered by Nikolay
Aleksandrov of Red Hat.

Users are advised to upgrade to these updated packages, which upgrade the
kernel-rt kernel to version kernel-rt-3.10.33-rt32.34 and correct these
issues. 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

• MRG Realtime 2 x86_64

Fixes

• BZ - 1070618 - CVE-2014-0100 kernel: net: inet frag code race condition leading to user-after-free
• BZ - 1083246 - CVE-2014-2672 kernel: ath9k: tid->sched race in ath_tx_aggr_sleep()
• BZ - 1083274 - CVE-2014-2678 kernel: net: rds: dereference of a NULL device in rds_iw_laddr_check()
• BZ - 1083512 - CVE-2014-2706 Kernel: net: mac80211: crash dues to AP powersave TX vs. wakeup race
• BZ - 1086730 - CVE-2014-2851 kernel: net: ping: refcount issue in ping_init_sock() function
• BZ - 1093076 - CVE-2014-3122 Kernel: mm: try_to_unmap_cluster() should lock_page() before mlocking
• BZ - 1094232 - CVE-2014-0196 kernel: pty layer race condition leading to memory corruption
• BZ - 1094299 - CVE-2014-1737 CVE-2014-1738 kernel: block: floppy: privilege escalation via FDRAWCMD floppy ioctl command

CVEs

• CVE-2014-0196
• CVE-2014-0100
• CVE-2014-2672
• CVE-2014-1737
• CVE-2014-3122
• CVE-2014-2678
• CVE-2014-2706
• CVE-2014-2851
• CVE-2014-1738

References

• https://access.redhat.com/security/updates/classification/#important