[Bug-tar] little bug in tar

[Klaus Stehle]

Hallo Paul Eggert or others,

There is a little bug in tar version >= 1.13.18

It appears when you set the environment variable TAR_OPTIONS to something
and use the old-style command line like

tar xvf blablabla.tar

_without_ the '-' sign.

The problem is that the 'old-style ==> new-style'-conversion routine
(function decode_options() in file tar.c)
doesn't copy the very last element  argv[argc],
which _should_ be a NULL pointer.

The following function prepend_default_options() relies on this
last NULL pointer and continues copying pointers of argv which don't
exist, so that tar crashes.



Here is the patch for the old-style-to-new-style-conversion routine in tar.c

--- src/tar.c.orig      2002-05-17 02:21:16.000000000 +0100
+++ src/tar.c           2004-04-15 19:38:30.342443200 +0100
@@ -534,7 +534,7 @@
       /* Allocate a new argument array, and copy program name in it.  */

       new_argc = argc - 1 + strlen (argv[1]);
-      new_argv = xmalloc (new_argc * sizeof (char *));
+      new_argv = xmalloc ((new_argc + 1) * sizeof (char *));
       in = argv;
       out = new_argv;
       *out++ = *in++;
@@ -559,7 +559,7 @@

       /* Copy all remaining options.  */

-      while (in < argv + argc)
+      while (in <= argv + argc)
        *out++ = *in++;

       /* Replace the old option list by the new one.  */



Cheers,
Klaus