RHSA-2015:1447 - Security Advisory

Topic

Updated grep packages that fix two security issues, several bugs, and add
various enhancements are now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Low security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Description

The grep utility searches through textual input for lines that contain a
match to a specified pattern and then prints the matching lines. The GNU
grep utilities include grep, egrep, and fgrep.

An integer overflow flaw, leading to a heap-based buffer overflow, was
found in the way grep parsed large lines of data. An attacker able to trick
a user into running grep on a specially crafted data file could use this
flaw to crash grep or, potentially, execute arbitrary code with the
privileges of the user running grep. (CVE-2012-5667)

A heap-based buffer overflow flaw was found in the way grep processed
certain pattern and text combinations. An attacker able to trick a user
into running grep on specially crafted input could use this flaw to crash
grep or, potentially, read from uninitialized memory. (CVE-2015-1345)

The grep packages have been upgraded to upstream version 2.20, which
provides a number of bug fixes and enhancements over the previous version.
Notably, the speed of various operations has been improved significantly.
Now, the recursive grep utility uses the fts function of the gnulib library
for directory traversal, so that it can handle much larger directories
without reporting the "File name too long" error message, and it can
operate faster when dealing with large directory hierarchies. (BZ#982215,
BZ#1064668, BZ#1126757, BZ#1167766, BZ#1171806)

This update also fixes the following bugs:

• Prior to this update, the \w and \W symbols were inconsistently matched

to the [:alnum:] character class. Consequently, regular expressions that used \w
and \W in some cases had incorrect results. An upstream patch which fixes the
matching problem has been applied, and \w is now matched to the [_[:alnum:]]
character and \W to the [^_[:alnum:]] character consistently. (BZ#799863)

• Previously, the "--fixed-regexp" command-line option was not included in

the grep(1) manual page. Consequently, the manual page was inconsistent
with the built-in help of the grep utility. To fix this bug, grep(1) has
been updated to include a note informing the user that "--fixed-regexp" is
an obsolete option. Now, the built-in help and manual page are consistent
regarding the "--fixed-regexp" option. (BZ#1103270)

• Previously, the Perl Compatible Regular Expression (PCRE) library did not

work correctly when matching non-UTF-8 text in UTF-8 mode. Consequently, an
error message about invalid UTF-8 byte sequence characters was returned.
To fix this bug, patches from upstream have been applied to the PCRE
library and the grep utility. As a result, PCRE now skips non-UTF-8
characters as non-matching text without returning any error message.
(BZ#1193030)

All grep users are advised to upgrade to these updated packages, which
correct these issues and add these enhancements.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 799863 - inconsistent \w and [[:alnum:]] behaviour
• BZ - 889935 - CVE-2012-5667 grep: Integer overflow leading to heap-based buffer-overflow when reading large lines
• BZ - 982215 - word boundary error near an utf8 character
• BZ - 1103270 - undocumented option --fixed-regexp
• BZ - 1167766 - grep Abandons (with core dump in some systems) when invoked with recurse and perl switches
• BZ - 1171806 - grep matches lowercase when only searching for uppercase range
• BZ - 1183651 - CVE-2015-1345 grep: heap buffer overrun

CVEs

• CVE-2015-1345
• CVE-2012-5667

References

• https://access.redhat.com/security/updates/classification/#low