Synopsis

Important: kernel-rt security and bug fix update

Type/Severity

Security Advisory: Important

Topic

An update for kernel-rt is now available for Red Hat Enterprise MRG 2.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• A flaw was found in the Linux kernel's key management system where it was possible for an attacker to escalate privileges or crash the machine. If a user key gets negatively instantiated, an error code is cached in the payload area. A negatively instantiated key may be then be positively instantiated by updating it with valid data. However, the ->update key type method must be aware that the error code may be there. (CVE-2015-8539, Important)
  
• It was found that fanout_add() in 'net/packet/af_packet.c' in the Linux kernel, before version 4.13.6, allows local users to gain privileges via crafted system calls that trigger mishandling of packet_fanout data structures, because of a race condition (involving fanout_add and packet_do_bind) that leads to a use-after-free bug. (CVE-2017-15649, Important)
  
• A vulnerability was found in the Linux kernel where the keyctl_set_reqkey_keyring() function leaks the thread keyring. This allows an unprivileged local user to exhaust kernel memory and thus cause a DoS. (CVE-2017-7472, Moderate)
  

Red Hat would like to thank Dmitry Vyukov of Google engineering for reporting CVE-2015-8539.

Bug Fix(es):

• The mlx5 driver has a number of configuration options, including the selective support for network protocols, such as InfiniBand and Ethernet. Due to a regression in the configuration of the MRG-RT kernel, the Ethernet mode of the driver was turned off. The regression has been resolved by enabling the mlx5 Ethernet mode, making the Ethernet protocol to work again. (BZ#1422778)
  
• The migrate_disable/enable() kernel operations are used to pin a thread to a CPU temporarily. This method is a kernel-rt specific. To keep RHEL-RT's kernel up-to-date with the latest real-time kernel, the migrate_disable/enable routine was updated to the version present on kernel v4.9-rt. However, this version showed to be problematic. The changes in the migrate_disable/enabled have been thus reverted to a stable version, avoiding the kernel BUG. (BZ#1507831)
  
• The kernel-rt packages have been upgraded to version 3.10.0-693.15.1.rt56.601, which provides a number of security and bug fixes over the previous version. (BZ#1519504)

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

• MRG Realtime 2 x86_64

Fixes

• BZ - 1284450 - CVE-2015-8539 kernel: local privesc in key management
• BZ - 1422778 - [mlx5] Failed to create device for nic_driver mlx5_core
• BZ - 1442086 - CVE-2017-7472 kernel: keyctl_set_reqkey_keyring() leaks thread keyrings
• BZ - 1504574 - CVE-2017-15649 kernel: Use-after-free in the af_packet.c
• BZ - 1519504 - update the MRG 2.5.z 3.10 kernel-rt sources

CVEs

• CVE-2015-8539
• CVE-2017-7472
• CVE-2017-15649

References

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

MRG Realtime 2

SRPM
kernel-rt-3.10.0-693.17.1.rt56.604.el6rt.src.rpm	SHA-256: 752ac6014d3a4976a1494b104251f1176626ba4395c92d36f34ea86f3d540149
x86_64
kernel-rt-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 1d7bd15a48bfc81c8f857ff5c6290b3cd2ea387ba68dbe9b41086c9353f4bd5b
kernel-rt-debug-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 45d86ae2ee46d4e4c88bc76b05d7ebc6f11a46de7a3806ad8897a0558fe7f809
kernel-rt-debug-debuginfo-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 4fb2fc21c2b163043dd6dc9e716b7e81e1745eacc74857135605e767e72346ef
kernel-rt-debug-devel-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 77079b7cf796b3e2fa2b1fbb9b87eca1cb206969a19e13a19eabf2406038d503
kernel-rt-debuginfo-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: c96372718f0d91f231fe25c9854a82feab7f8406079fbb7a83bd35e345dfc464
kernel-rt-debuginfo-common-x86_64-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 3f6a2ca3e377a573245aabcaec323dd1052a5c511d5dd60292bce8f1e6216af7
kernel-rt-devel-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 3c2ca0cc1f41a38e550192cbb352e8ba3b9cafb6282fc8b47f1abdaf016be049
kernel-rt-doc-3.10.0-693.17.1.rt56.604.el6rt.noarch.rpm	SHA-256: c3532c6d9e9ff81424cdedbcc529a89d1b35f292a44899e7b78fd888981eea9c
kernel-rt-firmware-3.10.0-693.17.1.rt56.604.el6rt.noarch.rpm	SHA-256: 7410441005a1b26af1d1ce47d235da3c162485d78372454c0169690d8ebbb280
kernel-rt-trace-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 3896f77bb732f7a6bcf4c19b6c842ac7ee8a30db915e428b695b272faa82fe14
kernel-rt-trace-debuginfo-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 2f96808cebbfebb2f123d502bc8b8651ca12f1da75b5b60fd30d2880c354d3dd
kernel-rt-trace-devel-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 19b5d6316d78794ca2115f0ba8ada9137518b97769ddd9d410347327589ebfe1
kernel-rt-vanilla-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: b195cc54df2fcc29aa28a46c69d1c10bb4458ff54ed8df073fda56d97924da32
kernel-rt-vanilla-debuginfo-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 86c234dbbedb0f65558ea2de28c2807aa5477b83ca07a0b4bf6ad9b3de7771ea
kernel-rt-vanilla-devel-3.10.0-693.17.1.rt56.604.el6rt.x86_64.rpm	SHA-256: 0ff5d32899e1eb31e9ec069e915712308ea8f2ad93a4dcb7080cb8aedc8d8f8e