avcodec/truemotion2rt: Check input buffer size

Fixes: Timeout
Fixes: 6250/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TRUEMOTION2RT_fuzzer-5479814011027456

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 8b5c29b6c2)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/truemotion2rt.c

@@ -116,6 +116,9 @@ static int truemotion2rt_decode_frame(AVCodecContext *avctx, void *data,
     if (ret < 0)
         return ret;
 
+    if (avctx->width / s->hscale * avctx->height * s->delta_size > avpkt->size * 8LL * 4)
+        return AVERROR_INVALIDDATA;
+
     ret = init_get_bits8(gb, avpkt->data + ret, avpkt->size - ret);
     if (ret < 0)
         return ret;