RHEL 7 : kernel (RHSA-2016:1277)
High Nessus Plugin ID 91801
SynopsisThe remote Red Hat host is missing one or more security updates.
DescriptionAn update for kernel is now available for Red Hat Enterprise Linux 7.
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.
The kernel packages contain the Linux kernel, the core of any Linux operating system.
These updated kernel packages include several security issues and numerous bug fixes, some of which you can see below. Space precludes documenting all of these bug fixes in this advisory. To see the complete list of bug fixes, users are directed to the related Knowledge Article: https://access.redhat.com/articles/2361921.
Security Fixes :
* 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.
* A race condition flaw was found in the way the Linux kernel's SCTP implementation handled sctp_accept() during the processing of heartbeat timeout events. A remote attacker could use this flaw to prevent further connections to be accepted by the SCTP server running on the system, resulting in a denial of service. (CVE-2015-8767, Moderate)
Red Hat would like to thank Jann Horn for reporting CVE-2016-4565.
Bug Fixes :
* When Small Computer System Interface (SCSI) devices were removed or deleted, a system crash could occur due to a race condition between listing all SCSI devices and SCSI device removal. The provided patch ensures that the starting node for the klist_iter_init_node() function is actually a member of the list before using it. As a result, a system crash no longer occurs in the described scenario. (BZ#1333403)
* This update offers a reworked series of patches for the resizable hash table (rhashtable) including a number of backported bug fixes and enhancements from upstream. (BZ#1328801)
* Previously, the same value of the mperf Model-Specific Register (MSR) read twice in a row could lead to a kernel panic due to the divide-by-zero error. The provided patch fixes this bug, and the kernel now handles two identical values of mperf gracefully.
* When a transparent proxy application was running and the number of established connections on the computer exceeded one million, unrelated processes, such as curl or ssh, were unable to bind to a local IP on the box to initiate a connection. The provided patch fixes the cooperation of the REUSEADDR/NOREUSEADDR socket option, and thus prevents the local port from being exhausted. As a result, the aforementioned bug no longer occurs in the described scenario.
* Previously, the kernel support for non-local bind for the IPv6 protocol was incomplete. As a consequence, an attempt to bind a socket to an IPv6 address that is not assigned to the host could fail. The provided patch includes changes in the ip_nonlocal_bind variable, which is now set to allow binding to an IPv6 address that is not assigned to the host. As a result, Linux servers are now able to bind to non-local IPv6 addresses as expected. (BZ#1324502)
* On some servers with a faster CPU, USB initialization could previously lead to a kernel hang during boot. If this inconvenience occurred when booting the second kernel during the kdump operation, the kdump service failed and the vmcore was lost. The provided upstream patch fixes this bug, and the kernel no longer hangs after USB initialization. (BZ#1327581)
* Previously, when running iperf servers using the mlx4_en module, a kernel panic occurred. The underlying source code has been fixed, and the kernel panic no longer occurs in the described scenario.
SolutionUpdate the affected packages.