[automerger] m4v_h263: add a test for invalid/negative value am: 7802c68aeb am: 08aa2367b5 am: 644ad716f0 am: c9528234a1 am: ee98fbf584

am: e82c14f41d

Change-Id: Iaddbc9ad1cc54addec6f1e20f7ed9bf1dd11552b

media/libstagefright/codecs/m4v_h263/dec/src/packet_util.cpp

@@ -52,7 +52,11 @@ PV_STATUS PV_ReadVideoPacketHeader(VideoDecData *video, int *next_MB)
         PV_BitstreamByteAlign(stream);
         BitstreamReadBits32(stream, resync_marker_length);
 
-        *next_MB = (int) BitstreamReadBits16(stream, nbits);
+        int mbnum = (int) BitstreamReadBits16(stream, nbits);
+        if (mbnum < 0) {
+            return PV_FAIL;
+        }
+        *next_MB = mbnum;
 //      if (*next_MB <= video->mbnum)   /*  needs more investigation */
 //          *next_MB = video->mbnum+1;