RHSA-2016:1100 - Security Advisory

Topic

An update for kernel is now available for Red Hat Enterprise Linux 6.6 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):

• 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)

Bug Fix(es):

• In anon_vma data structure, the degree counts number of child anon_vmas and of VMAs that point to this anon_vma. In the unlink_anon_vma() function, when its list is empty, anon_vma is going to be freed whether the external refcount is zero or not, so the parent's degree should be decremented. However, failure to decrement the degree triggered a BUG_ON() signal in unlink_anon_vma(). The provided patch fixes this bug, and the degree is now decremented as expected. (BZ#1326027)

Enhancement(s):

• The ixgbe NIC driver has been upgraded to upstream version 4.2.1, which provides a number of bug fixes and enhancements over the previous version. Notably:

NULL pointer crashes related to VLAN support have been fixed

Two more devices from the Intel X550 Ethernet controller family are now supported: IDs 15AC and 15AD

Several PHY-related problems have been addressed: link disruptions and link flapping

Added PHY-related support for Intel X550

System performance has been improved

(BZ#1315702)

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 6.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.6 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.6 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.6 ppc64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 i386
• Red Hat Enterprise Linux EUS Compute Node 6.6 x86_64
• Red Hat Enterprise Linux Server - AUS 6.6 x86_64
• Red Hat Enterprise Linux Server - TUS 6.6 x86_64

Fixes

• BZ - 1239029 - CVE-2015-5366 CVE-2015-5364 kernel: net: incorrect processing of checksums in UDP implementation

CVEs

• CVE-2015-5364
• CVE-2015-5366

References

• http://www.redhat.com/security/updates/classification/#normal