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