RHSA-2017:2869 - Security Advisory

Topic

An update for kernel is now available for Red Hat Enterprise Linux 7.2 Extended Update Support.

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

Security Fix(es):

• A race condition was found in the Linux kernel, present since v3.14-rc1 through v4.12. The race happens between threads of inotify_handle_event() and vfs_rename() while running the rename operation against the same file. As a result of the race the next slab data or the slab's free list pointer can be corrupted with attacker-controlled data, which may lead to the privilege escalation. (CVE-2017-7533, Important)

Red Hat would like to thank Leilei Lin (Alibaba Group), Fan Wu (The University of Hong Kong), and Shixiong Zhao (The University of Hong Kong) for reporting this issue.

Bug Fix(es):

• Previously, the 'stack:TID' annotation was applied to correctly mark the thread stack in a /proc/<pid>/maps file and it required processing the entire thread list to find the task of a stack Virtual Memory Area (VMA). Consequently, rendering and accessing /proc/<pid>/maps took a long time

on systems with a large number of threads running. This update removes the annotation to make the /proc/<pid>/maps and /proc/<pid>/numa_maps files usable for higher thread counts. As a result, the system performance while rendering and accessing /proc/<pid>/maps has improved significantly. (BZ#1481722)

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

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.2 x86_64
• Red Hat Enterprise Linux Server - AUS 7.2 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.2 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.2 ppc64
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.2 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.2 x86_64

Fixes

• BZ - 1468283 - CVE-2017-7533 kernel: a race between inotify_handle_event() and sys_rename()

CVEs

• CVE-2017-7533

References

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