From: Paul Eggert <eggert@Penguin.CS.UCLA.EDU>
Date: Sun, 30 Oct 2016 04:04:40 +0000 (-0700)
Subject: When extracting, skip ".." members
X-Git-Tag: release_1_30~36
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7340f67b9860ea0531c1450e5aa261c50f67165d;p=thirdparty%2Ftar.git

When extracting, skip ".." members

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

diff --git a/NEWS b/NEWS
index caa77bc1..07daaa76 100644
--- 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>
 
 
 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 f982433d..7904148f 100644
--- 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)))
     {