Scientific Linux Security Update : kernel on SL7.x x86_64

This script is Copyright (C) 2016 Tenable Network Security, Inc.

Synopsis :

The remote Scientific Linux host is missing one or more security

Description :

- It was found that the Linux kernel's keys subsystem did
not correctly garbage collect uninstantiated keyrings. A
local attacker could use this flaw to crash the system
or, potentially, escalate their privileges on the
system. (CVE-2015-7872, Important)

- A flaw was found in the way the Linux kernel handled
IRET faults during the processing of NMIs. An
unprivileged, local user could use this flaw to crash
the system or, potentially (although highly unlikely),
escalate their privileges on the system. (CVE-2015-5157,

This update also fixes the following bugs :

- Previously, processing packets with a lot of different
IPv6 source addresses caused the kernel to return
warnings concerning soft-lockups due to high lock
contention and latency increase. With this update, lock
contention is reduced by backing off concurrent waiting
threads on the lock. As a result, the kernel no longer
issues warnings in the described scenario.

- Prior to this update, block device readahead was
artificially limited. As a consequence, the read
performance was poor, especially on RAID devices. Now,
per-device readahead limits are used for each device
instead of a global limit. As a result, read performance
has improved, especially on RAID devices.

- After injecting an EEH error, the host was previously
not recovering and observing I/O hangs in HTX tool logs.
This update makes sure that when one or both of
is marked in the PE state, the PE's IO path is regarded
as enabled as well. As a result, the host no longer
hangs and recovers as expected.

- The genwqe device driver was previously using the
GFP_ATOMIC flag for allocating consecutive memory pages
from the kernel's atomic memory pool, even in non-atomic
situations. This could lead to allocation failures
during memory pressure. With this update, the genwqe
driver's memory allocations use the GFP_KERNEL flag, and
the driver can allocate memory even during memory
pressure situations.

- The nx842 co-processor for IBM Power Systems could in
some circumstances provide invalid data due to a data
corruption bug during uncompression. With this update,
all compression and uncompression calls to the nx842 co-
processor contain a cyclic redundancy check (CRC) flag,
which forces all compression and uncompression
operations to check data integrity and prevents the
co-processor from providing corrupted data.

- A failed 'updatepp' operation on the little-endian
variant of IBM Power Systems could previously cause a
wrong hash value to be used for the next hash insert
operation in the page table. This could result in a
missing hash pte update or invalidate operation,
potentially causing memory corruption. With this update,
the hash value is always recalculated after a failed
'updatepp' operation, avoiding memory corruption.

- Large Receive Offload (LRO) flag disabling was not being
propagated downwards from above devices in vlan and bond
hierarchy, breaking the flow of traffic. This problem
has been fixed and LRO flags now propagate correctly.

- Due to rounding errors in the CPU frequency of the
intel_pstate driver, the CPU frequency never reached the
value requested by the user. A kernel patch has been
applied to fix these rounding errors.

- When running several containers (up to 100), reports of
hung tasks were previously reported. This update fixes
the AB-BA deadlock in the dm_destroy() function, and the
hung reports no longer occur.

The system must be rebooted for this update to take effect.

See also :

Solution :

Update the affected packages.

Risk factor :

High / CVSS Base Score : 7.2

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 88799 ()

Bugtraq ID:

CVE ID: CVE-2015-5157

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