RHSA-2015:0285 - Security Advisory

Topic

Updated kernel packages that fix one security issue and three bugs are now
available for Red Hat Enterprise Linux 6.4 Extended Update Support.

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

Description

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

• A flaw was found in the way the Linux kernel's SCTP implementation

validated INIT chunks when performing Address Configuration Change
(ASCONF). A remote attacker could use this flaw to crash the system by
sending a specially crafted SCTP packet to trigger a NULL pointer
dereference on the system. (CVE-2014-7841, Important)

This issue was discovered by Liu Wei of Red Hat.

This update also fixes the following bugs:

• Due to several bugs in the network console logging, a race condition

between the network console send operation and the driver's IRQ handler
could occur, or the network console could access invalid memory content.
As a consequence, the respective driver, such as vmxnet3, triggered a
BUG_ON() assertion and the system terminated unexpectedly. A patch
addressing these bugs has been applied so that driver's IRQs are disabled
before processing the send operation and the network console now accesses
the RCU-protected (read-copy update) data properly. Systems using the
network console logging no longer crashes due to the aforementioned
conditions. (BZ#1165983)

• A bug in the vmxnet3 driver allowed potential race conditions to be

triggered when the driver was used with the netconsole module. The race
conditions allowed the driver's internal New API (NAPI) poll routine to run
concurrently with the netpoll controller routine, which resulted in data
corruption and a subsequent kernel panic. To fix this problem, the vmxnet3
driver has been modified to call the appropriate interrupt handler to
schedule NAPI poll requests properly. (BZ#1179594)

• Prior to this update, nfs_mark_return_delegation() was called without any

locking, resulting in unsafe dereferencing of delegation->inode.
Because the inode is only used to discover the nfs_client, the callers now
pass a valid pointer to the nfs_server as a parameter. (BZ#1187637)

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. The system must be
rebooted for this update to take effect.

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

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.4 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.4 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.4 ppc64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.4 i386
• Red Hat Gluster Storage Server for On-premise 2.1 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.1 x86_64
• Red Hat Enterprise Linux Server - AUS 6.4 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 6.4 x86_64

Fixes

• BZ - 1163087 - CVE-2014-7841 kernel: net: sctp: NULL pointer dereference in af->from_addr_param on malformed packet

CVEs

• CVE-2014-7841

References

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