Scientific Linux Security Update : kernel on SL5.x i386/x86_64

This script is Copyright (C) 2015-2016 Tenable Network Security, Inc.


Synopsis :

The remote Scientific Linux host is missing one or more security
updates.

Description :

- It was found that the Linux kernel's implementation of
vectored pipe read and write functionality did not take
into account the I/O vectors that were already processed
when retrying after a failed atomic access operation,
potentially resulting in memory corruption due to an I/O
vector array overrun. A local, unprivileged user could
use this flaw to crash the system or, potentially,
escalate their privileges on the system. (CVE-2015-1805,
Important)

This update fixes the following bugs :

- Due to a bug in the lpfc_device_reset_handler()
function, a scsi command timeout could lead to a system
crash. With this update, lpfc_device_reset_handler
recovers storage without crashing.

- Due to the code decrementing the reclaim_in_progress
counter without having incremented it first, severe
spinlock contention occurred in the shrink_zone()
function even though the vm.max_reclaims_in_progress
feature was set to 1. This update provides a patch
fixing the underlying source code, and spinlock
contention no longer occurs in this scenario.

- A TCP socket using SACK that had a retransmission but
recovered from it, failed to reset the retransmission
timestamp. As a consequence, on certain connections, if
a packet had to be re-transmitted, the retrans_stamp
variable was only cleared when the next acked packet was
received. This could lead to an early abortion of the
TCP connection if this next packet also got lost. With
this update, the socket clears retrans_stamp when the
recovery is completed, thus fixing the bug.

- Previously, the signal delivery paths did not clear the
TS_USEDFPU flag, which could cause problems in the
switch_to() function and lead to floating-point unit
(FPU) corruption. With this update, TS_USEDFPU is
cleared as expected, and FPU is no longer under threat
of corruption.

- A race condition in the exit_sem() function previously
caused the semaphore undo list corruption. As a
consequence, a kernel crash could occur. The corruption
in the semaphore undo list has been fixed, and the
kernel no longer crashes in this situation.

- Previously, when running the 'virsh blockresize [Device]
[Newsize]' command to resize the disk, the new size was
not reflected in a Scientific Linux 5 Virtual Machine
(VM). With this update, the new size is now reflected
online immediately in a Scientific Linux 5 VM so it is
no longer necessary to reboot the VM to see the new disk
size.

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

See also :

http://www.nessus.org/u?2701cee3

Solution :

Update the affected packages.

Risk factor :

High / CVSS Base Score : 7.2
(CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C)
Public Exploit Available : true

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 83969 ()

Bugtraq ID:

CVE ID: CVE-2015-1805

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