7.8 - RHSA-2015:1788

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Realtime (v. 7) - noarch, x86_64

3. 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.

4. 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

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

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