7.8 - RHSA-2015:1787

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:

MRG Realtime for RHEL 6 Server v.2 - noarch, x86_64

3. Description:

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

* 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 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.

This update provides a build of the kernel-rt package for Red Hat Enterprise MRG 2.5 that is layered on Red Hat Enterprise Linux 6, and fixes the following issues:

* Fix regression in scsi_send_eh_cmnd()

* boot hangs at "Console: switching to colour dummy device 80x25"

* Update tcp stack to 3.17 kernel

* ksoftirqd high CPU usage due to stray tasklet from ioatdma driver

(BZ#1245345)

This update also fixes the following bugs:

* The configuration option CONFIG_RTC_HCTOSYS was disabled on the realtime kernel causing the RTC clock to be adjusted with the UTC time even if the system is configured to set the RTC to the local time. By enabling the CONFIG_RTC_HCTOSYS configuration option, when the system is configured to use local time, RTC will correctly update with the local time and not try to use another timezone. (BZ#1248047)

* In the realtime kernel, if a rt_mutex was taken while in interrupt context the normal priority inheritance protocol would falsely identify a deadlock and trigger a kernel crash. The patch that added the rt_mutex in this interrupt context was reverted. (BZ#1250649)

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 1239029 - CVE-2015-5366 CVE-2015-5364 kernel: net: incorrect processing of checksums in UDP implementation 1245345 - RFE: update the MRG 2.5 3.10 kernel-rt sources 1245658 - CVE-2015-1333 kernel: denial of service due to memory leak in add_key()