Author: emaste
Date: Thu Apr  9 13:45:17 2015
New Revision: 281311
URL: https://svnweb.freebsd.org/changeset/base/281311

Log:
  ar: Disallow directory traversal
  
  Set ARCHIVE_EXTRACT_SECURE_SYMLINKS and ARCHIVE_EXTRACT_SECURE_NODOTDOT
  as in bsdtar to prevent extraction of archive entries whose pathnames
  contain .. or whose target directory would be altered by a symlink.
  Also disallow absolute pathnames.
  
  We don't currently provide an option to disable this behaviour (as
  bsdtar's -P does). It is unlikely to be a problem in practice for ar(1),
  but the -P option is not currently used and available if we want to
  consider it for this purpose.
  
  Differential Revision:        https://reviews.freebsd.org/D1524
  Reported by:  Alexander Cherepanov <chere...@mccme.ru>
  Approved by:  delphij
  Obtained from:        ELF tool chain ar, Ticket #474
  MFC after:    1 week
  Relnotes:     Yes
  Sponsored by: The FreeBSD Foundation

Modified:
  head/usr.bin/ar/read.c

Modified: head/usr.bin/ar/read.c
==============================================================================
--- head/usr.bin/ar/read.c      Thu Apr  9 13:09:05 2015        (r281310)
+++ head/usr.bin/ar/read.c      Thu Apr  9 13:45:17 2015        (r281311)
@@ -187,7 +187,15 @@ read_archive(struct bsdar *bsdar, char m
 
                                if (bsdar->options & AR_V)
                                        (void)fprintf(stdout, "x - %s\n", name);
-                               flags = 0;
+                               /* Disallow absolute paths. */
+                               if (name[0] == '/') {
+                                       bsdar_warnc(bsdar, 0,
+                                           "Absolute path '%s'", name);
+                                       continue;
+                               }
+                               /* Basic path security flags. */
+                               flags = ARCHIVE_EXTRACT_SECURE_SYMLINKS | \
+                                   ARCHIVE_EXTRACT_SECURE_NODOTDOT;
                                if (bsdar->options & AR_O)
                                        flags |= ARCHIVE_EXTRACT_TIME;
 
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"

Reply via email to