Bug 21163 (CVE-2015-8985) - Assertion failure in pop_fail_stack when executing a malformed regexp (CVE-2015-8985)
Summary: Assertion failure in pop_fail_stack when executing a malformed regexp (CVE-20...
Status: RESOLVED FIXED
Alias: CVE-2015-8985
Product: glibc
Classification: Unclassified
Component: regex (show other bugs)
Version: 2.24
: P2 normal
Target Milestone: 2.28
Assignee: Adhemerval Zanella
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-02-14 18:54 UTC by Florian Weimer
Modified: 2018-07-05 17:14 UTC (History)
2 users (show)

See Also:
Host:
Target:
Build:
Last reconfirmed:
fweimer: security-


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Description Florian Weimer 2017-02-14 18:54:22 UTC
Debian bug report:

  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=779392

Reproducer from the Debian bug:

#include <assert.h>
#include <regex.h>
#include <stdio.h>

int main(int argc, char **argv)
{
    int rc;
    regex_t preg;
    regmatch_t pmatch[2];

    rc = regcomp(&preg, "()*)|\\1)*", REG_EXTENDED);
    assert(rc == 0);
    regexec(&preg, "", 2, pmatch, 0);
    regfree(&preg);
    return 0;
}

This was assigned CVE-2015-8985 even though it is debatable whether this is a security bug.
Comment 1 Sourceware Commits 2018-07-04 12:56:25 UTC
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, master has been updated
       via  eb04c21373e2a2885f3d52ff192b0499afe3c672 (commit)
      from  b11643c21c5c9d67a69c8ae952e5231ce002e7f1 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=eb04c21373e2a2885f3d52ff192b0499afe3c672

commit eb04c21373e2a2885f3d52ff192b0499afe3c672
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Dec 20 09:47:44 2017 -0200

    posix: Sync gnulib regex implementation
    
    This patch syncs the regex implementation with gnulib (commit 0ee5212).
    Only two changes in GLIBC regex testing are required:
    
      1. posix/bug-regex28.c: as previously discussed [1] the change of
         expected results on the pattern should be safe.
    
      2. posix/PCRE.tests: the ERE (a)|\1 is malformed (in the sense that
         the \1 doesn't mean anything) and although current GLIBC accepts
         it has undefined behavior.  This patch removes the specific test.
    
    This sync contains some patches from thread 'Regex: Make libc regex
    more usable outside GLIBC.' [2] which have been pushed upstream in
    gnulib.  This patches also fixes some regex issues (BZ #23233,
    BZ #21163, BZ #18986, BZ #13762) and I did not add testcases for
    both #23233 and #13762 because I couldn't think a simple way to
    trigger the expected failure path to trigger them.
    
    Checked on x86_64-linux-gnu and i686-linux-gnu.
    
    	[BZ #23233]
    	[BZ #21163]
    	[BZ #18986]
    	[BZ #13762]
    	* posix/Makefile (tests): Add bug-regex37 and bug-regex38.
    	* posix/PCRE.tests: Remove invalid test.
    	* posix/bug-regex28.c: Fix expected values for used syntax.
    	* posix/bug-regex37.c: New file.
    	* posix/bug-regex38.c: Likewise.
    	* posix/regcomp.c: Sync with gnulib.
    	* posix/regex.c: Likewise.
    	* posix/regex.h: Likewise.
    	* posix/regex_internal.c: Likewise.
    	* posix/regex_internal.h: Likewise.
    	* posix/regexec.c: Likewise.
    
    [1] https://sourceware.org/ml/libc-alpha/2017-12/msg00807.html
    [2] https://sourceware.org/ml/libc-alpha/2017-12/msg00237.html

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                       |   18 +
 posix/Makefile                                  |    3 +-
 posix/PCRE.tests                                |   13 -
 posix/bug-regex28.c                             |   46 +-
 wcsmbs/test-char-types.c => posix/bug-regex37.c |   11 +-
 wcsmbs/test-char-types.c => posix/bug-regex38.c |   11 +-
 posix/regcomp.c                                 |  597 +++++++++------
 posix/regex.c                                   |   21 +-
 posix/regex.h                                   |  335 +++++----
 posix/regex_internal.c                          |  295 ++++----
 posix/regex_internal.h                          |  442 ++++++++----
 posix/regexec.c                                 |  936 ++++++++++++-----------
 12 files changed, 1557 insertions(+), 1171 deletions(-)
 copy wcsmbs/test-char-types.c => posix/bug-regex37.c (78%)
 copy wcsmbs/test-char-types.c => posix/bug-regex38.c (78%)
Comment 2 Adhemerval Zanella 2018-07-04 12:59:22 UTC
Fixed by eb04c21373e2a2885f3d52ff192b0499afe3c672 (2.28).
Comment 3 Adhemerval Zanella 2018-07-05 17:14:18 UTC
Fixed.