1 files changed, 20 insertions, 2 deletions

diff --git a/archival/tar.c b/archival/tar.c
index 1d6e63da0..150c6f393 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -23,9 +23,28 @@
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
+/* TODO: security with -C DESTDIR option can be enhanced.
+ * Consider tar file created via:
+ * $ tar cvf bug.tar anything.txt
+ * $ ln -s /tmp symlink
+ * $ tar --append -f bug.tar symlink
+ * $ rm symlink
+ * $ mkdir symlink
+ * $ tar --append -f bug.tar symlink/evil.py
+ *
+ * This will result in an archive which contains:
+ * $ tar --list -f bug.tar
+ * anything.txt
+ * symlink
+ * symlink/evil.py
+ *
+ * Untarring it puts evil.py in '/tmp' even if the -C DESTDIR is given.
+ * This doesn't feel right, and IIRC GNU tar doesn't do that.
+ */
+
 #include <fnmatch.h>
 #include "libbb.h"
-#include "unarchive.h"
+#include "archive.h"
 /* FIXME: Stop using this non-standard feature */
 #ifndef FNM_LEADING_DIR
 # define FNM_LEADING_DIR 0
@@ -884,7 +903,6 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
         /* Prepend '-' to the first argument if required */
         opt_complementary = "--:" // first arg is options
                 "tt:vv:" // count -t,-v
-                "?:" // bail out with usage instead of error return
                 "X::T::" // cumulative lists
 #if ENABLE_FEATURE_TAR_LONG_OPTIONS && ENABLE_FEATURE_TAR_FROM
                 "\xff::" // cumulative lists for --exclude