Merge commit 'cd4663dc80323ba64989d0c103d51ad3ee0e9c2f'

* commit 'cd4663dc80323ba64989d0c103d51ad3ee0e9c2f':
  smacker: add sanity check for length in smacker_decode_tree()

See b829da3639

Merged-by: James Almer <jamrial@gmail.com>

libavcodec/smacker.c

@@ -43,6 +43,7 @@
 #define SMKTREE_BITS 9
 #define SMK_NODE 0x80000000
 
+#define SMKTREE_DECODE_MAX_RECURSION 32
 
 typedef struct SmackVContext {
     AVCodecContext *avctx;
@@ -95,10 +96,11 @@ enum SmkBlockTypes {
  */
 static int smacker_decode_tree(GetBitContext *gb, HuffContext *hc, uint32_t prefix, int length)
 {
-    if(length > 32 || length > 3*SMKTREE_BITS) {
+    if (length > SMKTREE_DECODE_MAX_RECURSION || length > 3 * SMKTREE_BITS) {
-        av_log(NULL, AV_LOG_ERROR, "length too long\n");
+        av_log(NULL, AV_LOG_ERROR, "Maximum tree recursion level exceeded.\n");
         return AVERROR_INVALIDDATA;
     }
+
     if(!get_bits1(gb)){ //Leaf
         if(hc->current >= hc->length){
             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");