Synopsis

Important: kernel-rt security and bug fix update

Type/Severity

Security Advisory: Important

Topic

An update for kernel-rt is now available for Red Hat Enterprise MRG 2.5.

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-rt package contain the Linux kernel, the core of any Linux
operating system.

This update provides a build of the kernel-rt package for Red Hat
Enterprise MRG 2.5 that is layered on Red Hat Enterprise Linux 6, and
provides a number of bug fixes including:

• [netdrv] ixgbevf: fix spoofed packets with random MAC and use ether_addr_copy instead of memcpy
• [mm] mmu_notifier: fix memory corruption
• [mm] hugetlbfs: optimize when NUMA=n
• [mm] optimize put_mems_allowed() usage
• [x86] mm: suitable memory should go to ZONE_MOVABLE
• [fs] xfs: fix splice/direct-IO deadlock
• [acpi] tables: Add acpi_subtable_proc to ACPI table parsers
• [acpi] table: Add new function to get table entries
• [net] ipv6: Nonlocal bind
• [net] ipv4: bind ip_nonlocal_bind to current netns

(BZ#1332298)

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)

• 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)

• A flaw was found in the way the realtime kernel processed specially

crafted ICMP echo requests. A remote attacker could use this flaw to
trigger a sysrql function based on values in the ICMP packet, allowing them
to remotely restart the system. Note that this feature is not enabled by
default and requires elevated privileges to be configured. (CVE-2016-3707,
Moderate)

Red Hat would like to thank Jann Horn for reporting CVE-2016-4565.

Bug Fix(es):

• An oops can occur in the hpsa driver while submitting ioaccel2 commands

when the phys_disk pointer is NULL (in hpsa_scsi_ioaccel_raid_map).
Configuration changes during I/O operations could set the phys_disk
pointer to NULL. In this case, send the command down the RAID path for
correct processing, avoiding the oops. (BZ#1334260)

• A faulty code merge left an extra spin_lock operation in the function

fscache_invalidate_write(). The code has been correctly updated to remove
this extra lock operation, which avoids a potential deadlock situation
when looping through cache pages. (BZ#1327730)

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

• MRG Realtime 2 x86_64

Fixes

• BZ - 1297389 - CVE-2015-8767 kernel: SCTP denial of service during timeout
• BZ - 1310570 - CVE-2016-4565 kernel: infiniband: Unprivileged process can overwrite kernel memory using rdma_ucm.ko
• BZ - 1327484 - CVE-2016-3707 kernel-rt: Sending SysRq command via ICMP echo request
• BZ - 1327730 - deadlock in fscache code (merge error) [mrg]
• BZ - 1332298 - update the MRG 2.5.z 3.10 kernel-rt sources

CVEs

• CVE-2015-8767
• CVE-2016-3707
• CVE-2016-4565

References