commit f4c79584d01c6394544c86c122d2f32f77a1d02d
Author: Michael Schroeder <mls@suse.de>
Date:   Wed May 18 09:04:40 2011 +0300

    Always copy macro source when expanding it
    - A macro can undefine itself, and unless we grab a copy of it we'll
      end up accessing already freed memory. Fixes a regression from
      commit ebc4ceaaeb8bb59019f4635471b28eb5f3eaaaa6 which assumed
      a copy is not always needed.
    
    Signed-off-by: Panu Matilainen <pmatilai@redhat.com>

diff --git a/rpmio/macro.c b/rpmio/macro.c
index 8ea4819..d79ef18 100644
--- a/rpmio/macro.c
+++ b/rpmio/macro.c
@@ -1022,12 +1022,12 @@ expandMacro(MacroBuf mb, const char *src, size_t slen)
     char *source = NULL;
 
     /* Handle non-terminated substrings by creating a terminated copy */
-    if (slen > 0) {
-	source = xmalloc(slen + 1);
-	strncpy(source, src, slen);
-	source[slen] = '\0';
-	s = source;
-    }
+    if (!slen)
+	slen = strlen(src);
+    source = xmalloc(slen + 1);
+    strncpy(source, src, slen);
+    source[slen] = '\0';
+    s = source;
 
     if (mb->buf == NULL) {
 	size_t blen = MACROBUFSIZ + strlen(s);