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Gentoo Linux Security Advisory                           GLSA 201702-21
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                                           https://security.gentoo.org/
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 Severity: Normal
    Title: Opus: User-assisted execution of arbitrary code
     Date: February 20, 2017
     Bugs: #605894
       ID: 201702-21

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Synopsis
========

A vulnerability in Opus could cause memory corruption.

Background
==========

Opus is a totally open, royalty-free, highly versatile audio codec.

Affected packages
=================

    -------------------------------------------------------------------
     Package              /     Vulnerable     /            Unaffected
    -------------------------------------------------------------------
  1  media-libs/opus             < 1.1.3-r1               >= 1.1.3-r1

Description
===========

A large NLSF values could cause the stabilization code in
silk/NLSF_stabilize.c to wrap-around and have the last value in
NLSF_Q15[] to be negative, close to -32768.

Under normal circumstances, the code will simply read from the wrong
table resulting in an unstable LPC filter. The filter would then go
through the LPC stabilization code at the end of silk_NLSF2A().

Ultimately, the output audio would be garbage, but no worse than with
any other harmless bad packet.

Please see the referenced upstream patch and Debian bug report below
for a detailed analysis.

However, the original report was about a successful exploitation of
Android's Mediaserver in conjunction with this vulnerability.

Impact
======

A remote attacker could entice a user to open a specially crafted media
stream, possibly resulting in execution of arbitrary code with the
privileges of the process, or a Denial of Service condition.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Opus users should upgrade to the latest version:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=media-libs/opus-1.1.3-r1"

References
==========

[ 1 ] CVE-2017-0381
      http://nvd.nist.gov/nvd.cfm?cvename=CVE-2017-0381
[ 2 ] Debian Bug 851612
      https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=851612#10
[ 3 ] Upstream patch
      https://git.xiph.org/?p=opus.git;a=commitdiff;h=70a3d641b

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

 https://security.gentoo.org/glsa/201702-21

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users' machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
https://bugs.gentoo.org.

License
=======

Copyright 2017 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.5


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