mxftypes: Don't store pointers in stack allocated guints

This works usually in this place, unless the compiler optimizes things in
interesting ways in which case it causes stack corruption and crashes later.

The compiler in question here is clang with -O1, which seems to pack the stack
a bit more and causes writing to the guint as pointer to overwrite map.memory,
which then later crashes during unmapping of the memory.

diff --git a/gst/mxf/mxftypes.c b/gst/mxf/mxftypes.c
index ab04427..a2af02e 100644 (file)
--- a/gst/mxf/mxftypes.c
+++ b/gst/mxf/mxftypes.c
@@ -1585,15 +1585,14 @@ mxf_primer_pack_to_buffer (const MXFPrimerPack * pack)
   data += 8;
 
   if (pack->mappings) {
-    guint local_tag;
+    gpointer local_tag;
     MXFUL *ul;
     GHashTableIter iter;
 
     g_hash_table_iter_init (&iter, pack->mappings);
 
-    while (g_hash_table_iter_next (&iter, (gpointer) & local_tag,
-            (gpointer) & ul)) {
-      GST_WRITE_UINT16_BE (data, local_tag);
+    while (g_hash_table_iter_next (&iter, &local_tag, (gpointer) & ul)) {
+      GST_WRITE_UINT16_BE (data, GPOINTER_TO_UINT (local_tag));
       memcpy (data + 2, ul, 16);
       data += 18;
     }