5 - RHSA-2015:0285

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Compute Node Optional EUS (v. 6.4) - x86_64 Red Hat Enterprise Linux HPC Node EUS (v. 6.4) - noarch, x86_64 Red Hat Enterprise Linux Server EUS (v. 6.4) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional EUS (v. 6.4) - i386, ppc64, s390x, x86_64

3. 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.

4. 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

5. Bugs fixed (https://bugzilla.redhat.com/):

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