commit 147018e729e7c22eeabf15b82d26e4bf68a0d18e

Author: Alexander Cherepanov <cherepan@mccme.ru>

Date:   Sun Dec 28 19:57:19 2014 +0300

    libelf: Fix dir traversal vuln in ar extraction.

    read_long_names terminates names at the first '/' found but then skips

    one character without checking (it's supposed to be '\n'). Hence the

    next name could start with any character including '/'. This leads to

    a directory traversal vulnerability at the time the contents of the

    archive is extracted.

    The danger is mitigated by the fact that only one '/' is possible in a

    resulting filename and only in the leading position. Hence only files

    in the root directory can be written via this vuln and only when ar is

    executed as root.

    The fix for the vuln is to not skip any characters while looking

    for '/'.

    Signed-off-by: Alexander Cherepanov <cherepan@mccme.ru>

diff --git a/libelf/ChangeLog b/libelf/ChangeLog

index 3b88d03..447c354 100644

--- a/libelf/ChangeLog

+++ b/libelf/ChangeLog

@@ -1,3 +1,8 @@

+2014-12-28  Alexander Cherepanov  <cherepan@mccme.ru>

+

+	* elf_begin.c (read_long_names): Don't miss '/' right after

+	another '/'. Fixes a dir traversal vuln in ar extraction.

+

 2014-12-18  Ulrich Drepper  <drepper@gmail.com>

 	* Makefile.am: Suppress output of textrel_check command.

diff --git a/libelf/elf_begin.c b/libelf/elf_begin.c

index 30abe0b..cd3756c 100644

--- a/libelf/elf_begin.c

+++ b/libelf/elf_begin.c

@@ -749,10 +749,7 @@ read_long_names (Elf *elf)

 	    }

 	  /* NUL-terminate the string.  */

-	  *runp = '\0';

-

-	  /* Skip the NUL byte and the \012.  */

-	  runp += 2;

+	  *runp++ = '\0';

 	  /* A sanity check.  Somebody might have generated invalid

 	     archive.  */