7.2 - RHSA-2016:1640

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux HPC Node EUS (v. 6.6) - noarch, x86_64 Red Hat Enterprise Linux HPC Node Optional EUS (v. 6.6) - x86_64 Red Hat Enterprise Linux Server EUS (v. 6.6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional EUS (v. 6.6) - i386, ppc64, s390x, x86_64

3. Description:

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

Security Fix(es):

* A flaw was found in the way certain interfaces of the Linux kernel's Infiniband subsystem used write() as bi-directional ioctl() replacement, which could lead to insufficient memory security checks when being invoked using the splice() system call. A local unprivileged user on a system with either Infiniband hardware present or RDMA Userspace Connection Manager Access module explicitly loaded, could use this flaw to escalate their privileges on the system. (CVE-2016-4565, Important)

Red Hat would like to thank Jann Horn for reporting this issue.

Bug Fix(es):

* After upgrading the kernel, the CPU load average was higher compared to the prior kernel version due to the modification of the scheduler. The provided patchset rolls back the calculation algorithm of the load average to the status of the previous system version, thus resulting in lower values in the same system load. (BZ#1343013)

4. 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.

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

1310570 - CVE-2016-4565 kernel: infiniband: Unprivileged process can overwrite kernel memory using rdma_ucm.ko