RHSA-2015:1788 - Security Advisory

Topic

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

Red Hat Product Security 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 flaw was found in the kernel's implementation of the Berkeley Packet

Filter (BPF). A local attacker could craft BPF code to crash the system by
creating a situation in which the JIT compiler would fail to correctly
optimize the JIT image on the last pass. This would lead to the CPU
executing instructions that were not part of the JIT code. (CVE-2015-4700,
Important)

• Two flaws were found in the way the Linux kernel's networking

implementation handled UDP packets with incorrect checksum values. A remote
attacker could potentially use these flaws to trigger an infinite loop in
the kernel, resulting in a denial of service on the system, or cause a
denial of service in applications using the edge triggered epoll
functionality. (CVE-2015-5364, CVE-2015-5366, Important)

• A flaw was found in the way the Linux kernel's ext4 file system handled

the "page size > block size" condition when the fallocate zero range
functionality was used. A local attacker could use this flaw to crash the
system. (CVE-2015-0275, Moderate)

• It was found that the Linux kernel's keyring implementation would leak

memory when adding a key to a keyring via the add_key() function. A local
attacker could use this flaw to exhaust all available memory on the system.
(CVE-2015-1333, Moderate)

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

implementation handled Address Configuration lists when performing Address
Configuration Change (ASCONF). A local attacker could use this flaw to
crash the system via a race condition triggered by setting certain ASCONF
options on a socket. (CVE-2015-3212, Moderate)

• An information leak flaw was found in the way the Linux kernel's Virtual

Dynamic Shared Object (vDSO) implementation performed address
randomization. A local, unprivileged user could use this flaw to leak
kernel memory addresses to user-space. (CVE-2014-9585, Low)

Red Hat would like to thank Daniel Borkmann for reporting CVE-2015-4700,
and Canonical for reporting the CVE-2015-1333 issue. The CVE-2015-0275
issue was discovered by Xiong Zhou of Red Hat, and the CVE-2015-3212 issue
was discovered by Ji Jianwen of Red Hat Engineering.

The kernel-rt packages have been upgraded to version 3.10.0-229.13.1, which
provides a number of bug fixes and enhancements over the previous version,
including:

• Fix regression in scsi_send_eh_cmnd()
• boot hangs at "Console: switching to colour dummy device 80x25"
• Update tcp stack to 3.17 kernel
• Missing some code from patch "(...) Fix VGA switcheroo problem related to

hotplug"

• ksoftirqd high CPU usage due to stray tasklet from ioatdma driver
• During Live Partition Mobility (LPM) testing, RHEL 7.1 LPARs will crash

in kmem_cache_alloc

(BZ#1253809)

This update also fixes the following bug:

• The hwlat_detector.ko module samples the clock and records any intervals

between reads that exceed a specified threshold. However, the module
previously tracked the maximum interval seen for the "inner" interval but
did not record when the "outer" interval was greater. A patch has been
applied to fix this bug, and hwlat_detector.ko now correctly records if the
outer interval is the maximal interval encountered during the run.
(BZ#1252365)

All kernel-rt users are advised to upgrade to these updated packages, which
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.

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

Fixes

• BZ - 1181054 - CVE-2014-9585 kernel: ASLR bruteforce possible for vdso library
• BZ - 1193907 - CVE-2015-0275 kernel: fs: ext4: fallocate zero range page size > block size BUG()
• BZ - 1226442 - CVE-2015-3212 kernel: SCTP race condition allows list corruption and panic from userlevel
• BZ - 1233615 - CVE-2015-4700 kernel: Crafted BPF filters may crash kernel during JIT optimisation
• BZ - 1239029 - CVE-2015-5366 CVE-2015-5364 kernel: net: incorrect processing of checksums in UDP implementation
• BZ - 1245658 - CVE-2015-1333 kernel: denial of service due to memory leak in add_key()
• BZ - 1253809 - kernel-rt: update to the RHEL7.1.z batch 5 source tree

CVEs

• CVE-2014-9585
• CVE-2015-0275
• CVE-2015-1333
• CVE-2015-3212
• CVE-2015-4700
• CVE-2015-5364
• CVE-2015-5366

References

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