[LU-8996] kernel update [RHEL6.8 2.6.32-642.13.1.el6]

Tue, 24 Jan 2017 14:38:51 +0000

Security Fix(es):

A use-after-free vulnerability was found in the kernels socket recvmmsg
subsystem. This may allow remote attackers to corrupt memory and may allow
execution of arbitrary code. This corruption takes place during the error
handling routines within __sys_recvmmsg() function. (CVE-2016-7117, Important)

An out-of-bounds heap memory access leading to a Denial of Service, heap
disclosure, or further impact was found in setsockopt(). The function call is
normally restricted to root, however some processes with cap_sys_admin may also
be able to trigger this flaw in privileged container environments.
(CVE-2016-4998, Moderate)

A use-after-free vulnerability was found in tcp_xmit_retransmit_queue and
other tcp_* functions. This condition could allow an attacker to send an
incorrect selective acknowledgment to existing connections, possibly resetting a
connection. (CVE-2016-6828, Moderate)

Bug Fix(es):

When parallel NFS returned a file layout, a kernel crash sometimes occurred.
This update removes the call to the BUG_ON() function from a code path of a
client that returns the file layout. As a result, the kernel no longer crashes
in the described situation. (BZ#1385480)

When a guest virtual machine (VM) on Microsoft Hyper-V was set to crash on a
Nonmaskable Interrupt (NMI) that was injected from the host, this VM became
unresponsive and did not create the vmcore dump file. This update applies a set
of patches to the Virtual Machine Bus kernel driver (hv_vmbus) that fix this
bug. As a result, the VM now first creates and saves the vmcore dump file and
then reboots. (BZ#1385482)

From Red Hat Enterprise Linux 6.6 to 6.8, the IPv6 routing cache occasionally
showed incorrect values. This update fixes the DST_NOCOUNT mechanism, and the
IPv6 routing cache now shows correct values. (BZ#1391974)

When using the ixgbe driver and the software Fibre Channel over Ethernet
(FCoE) stack, suboptimal performance in some cases occurred on systems with a
large number of CPUs. This update fixes the fc_exch_alloc() function to try all
the available exchange managers in the list for an available exchange ID. This
change avoids failing allocations, which previously led to the host busy status.
(BZ#1392818)

When the vmwgfx kernel module loads, it overrides the boot resolution
automatically. Consequently, users were not able to change the resolution by
manual setting of the kernel's 'vga=' parameter in the /boot/grub/grub.conf
file. This update adds the 'nomodeset' parameter, which can be set in the
/boot/grub/grub.conf file. The 'nomodeset' parameter allows the users to prevent
the vmwgfx driver from loading. As a result, the setting of the 'vga=' parameter
works as expected, in case that vmwgfx does not load. (BZ#1392875)

When Red Hat Enterprise Linux 6.8 was booted on SMBIOS 3.0 based systems,
Desktop Management Interface (DMI) information, which is referenced by several
applications, such as NEC server's memory RAS utility, was missing entries in
the sysfs virtual file system. This update fixes the underlying source code, and
sysfs now shows the DMI information as expected. (BZ#1393464)

Previously, bonding mode active backup and the propagation of the media access
control (MAC) address to a VLAN interface did not work in Red Hat Enterprise
Linux 6.8, when the fail_over_mac bonding parameter was set to
fail_over_mac=active. With this update, the underlying source code has been
fixed so that the VLANs continue inheriting the MAC address of the active
physical interface until the VLAN MAC address is explicitly set to any value. As
a result, IPv6 EUI64 addresses for the VLAN can reflect any changes to the MAC
address of the physical interface, and Duplicate Address Detection (DAD) behaves
as expected. (BZ#1396479)

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

1349886 - CVE-2016-4998 kernel: out of bounds reads when processing IPT_SO_SET_REPLACE setsockopt
1367091 - CVE-2016-6828 kernel: Use after free in tcp_xmit_retransmit_queue
1382268 - CVE-2016-7117 kernel: Use-after-free in the recvmmsg exit path

Whamcloud Community JIRA

[LU-8996] kernel update [RHEL6.8 2.6.32-642.13.1.el6]