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redhatRedHatRHSA-2018:0181
HistoryJan 25, 2018 - 11:09 a.m.

(RHSA-2018:0181) Important: kernel-rt security and bug fix update

2018-01-2511:09:51
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54

CVSS2

7.2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0

Percentile

10.1%

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)

CVSS2

7.2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0

Percentile

10.1%