Gentoo: GNU C Library Integer overflow
Posted by Benjamin D. Thomas   
Gentoo An integer overflow in the dynamic loader, ld.so, could result in the execution of arbitrary code with escalated privileges.As the hardware capabilities mask is honored by the dynamic loader during the execution of suid and sgid programs, in theory this vulnerability could result in the execution of arbitrary code with root privileges. This update is provided as a precaution against currently unknown attack vectors.
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Gentoo Linux Security Advisory                           GLSA 200707-04
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: GNU C Library: Integer overflow
      Date: July 03, 2007
      Bugs: #183844
        ID: 200707-04

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Synopsis
========

An integer overflow in the dynamic loader, ld.so, could result in the
execution of arbitrary code with escalated privileges.

Background
==========

The GNU C library is the standard C library used by Gentoo Linux
systems. It provides programs with basic facilities and interfaces to
system calls. ld.so is the dynamic linker which prepares dynamically
linked programs for execution by resolving runtime dependencies and
related functions.

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

    -------------------------------------------------------------------
     Package         /  Vulnerable  /                       Unaffected
    -------------------------------------------------------------------
  1  sys-libs/glibc      < 2.5-r4                            >= 2.5-r4
    -------------------------------------------------------------------
     # Package 1 only applies to x86 users.

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

Tavis Ormandy of the Gentoo Linux Security Team discovered a flaw in
the handling of the hardware capabilities mask by the dynamic loader.
If a mask is specified with a high population count, an integer
overflow could occur when allocating memory.

Impact
======

As the hardware capabilities mask is honored by the dynamic loader
during the execution of suid and sgid programs, in theory this
vulnerability could result in the execution of arbitrary code with root
privileges. This update is provided as a precaution against currently
unknown attack vectors.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=sys-libs/glibc-2.5-r4"

References
==========

  [ 1 ] CVE-2007-3508
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3508

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

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

  http://security.gentoo.org/glsa/glsa-200707-04.xml

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
http://bugs.gentoo.org.

License
=======

Copyright 2007 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