1 files changed, 6 insertions, 4 deletions
diff --git a/resolv/mapv4v6addr.h b/resolv/mapv4v6addr.h
index 7f85f7d5e3..bc3290f162 100644
--- a/resolv/mapv4v6addr.h
+++ b/resolv/mapv4v6addr.h
@@ -56,14 +56,16 @@ static void
 map_v4v6_address (const char *src, char *dst)
 {
   u_char *p = (u_char *) dst;
+  char tmp[INADDRSZ];
   int i;
 
-  /* Move the IPv4 part to the right position.  */
-  memcpy (dst + 12, src, INADDRSZ);
-
+  /* Stash a temporary copy so our caller can update in place. */
+  memcpy (tmp, src, INADDRSZ);
   /* Mark this ipv6 addr as a mapped ipv4. */
   for (i = 0; i < 10; i++)
     *p++ = 0x00;
   *p++ = 0xff;
-  *p = 0xff;
+  *p++ = 0xff;
+  /* Retrieve the saved copy and we're done. */
+  memcpy ((void *) p, tmp, INADDRSZ);
 }