When extracting, skip ".." members

* NEWS: Document this.
* src/extract.c (extract_archive): Skip members whose names
contain "..".

diff --git a/NEWS b/NEWS
index caa77bc1f7ddefd73fbb528bfdaeccf6947f42de..07daaa766691923103dbd2e0494274f5002ba68e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,9 +1,15 @@
-GNU tar NEWS - User visible changes. 2016-05-27
+GNU tar NEWS - User visible changes. 2016-10-29
 Please send GNU tar bug reports to <bug-tar@gnu.org>
 
 \f
 version 1.29.90 (Git)
 
+* Member names containing '..' components are now skipped when extracting.
+
+This fixes tar's behavior to match its documentation, and is a bit
+safer when extracting untrusted archives over old files (an unsafe
+practice that the tar manual has long recommended against).
+
 * Report erroneous use of positional options.
 
 During archive creation or update, tar keeps track of positional

diff --git a/src/extract.c b/src/extract.c
index f982433d77fff9aff5e30a8f28fa62b767b63b99..7904148faee7df5cbaa06bbf047d1fc834ddae51 100644 (file)
--- a/src/extract.c
+++ b/src/extract.c
@@ -1629,12 +1629,20 @@ extract_archive (void)
 {
   char typeflag;
   tar_extractor_t fun;
+  bool skip_dotdot_name;
 
   fatal_exit_hook = extract_finish;
 
   set_next_block_after (current_header);
 
+  skip_dotdot_name = (!absolute_names_option
+                     && contains_dot_dot (current_stat_info.orig_file_name));
+  if (skip_dotdot_name)
+    ERROR ((0, 0, _("%s: Member name contains '..'"),
+           quotearg_colon (current_stat_info.orig_file_name)));
+
   if (!current_stat_info.file_name[0]
+      || skip_dotdot_name
       || (interactive_option
          && !confirm ("extract", current_stat_info.file_name)))
     {