avcodec/truemotion2: Propagate out of bounds error from GET_TOK()

Fixes: Timeout
Fixes: 6389/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TRUEMOTION2_fuzzer-5695918121680896

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/truemotion2.c

@@ -63,6 +63,7 @@ typedef struct TM2Context {
     AVFrame *pic;
 
     GetBitContext gb;
+    int error;
     BswapDSPContext bdsp;
 
     uint8_t *buffer;
@@ -398,6 +399,7 @@ static inline int GET_TOK(TM2Context *ctx,int type)
 {
     if (ctx->tok_ptrs[type] >= ctx->tok_lens[type]) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Read token from stream %i out of bounds (%i>=%i)\n", type, ctx->tok_ptrs[type], ctx->tok_lens[type]);
+        ctx->error = 1;
         return 0;
     }
     if (type <= TM2_MOT) {
@@ -809,6 +811,8 @@ static int tm2_decode_blocks(TM2Context *ctx, AVFrame *p)
             default:
                 av_log(ctx->avctx, AV_LOG_ERROR, "Skipping unknown block type %i\n", type);
             }
+            if (ctx->error)
+                return AVERROR_INVALIDDATA;
         }
     }
 
@@ -889,6 +893,8 @@ static int decode_frame(AVCodecContext *avctx,
     int offset           = TM2_HEADER_SIZE;
     int i, t, ret;
 
+    l->error = 0;
+
     av_fast_padded_malloc(&l->buffer, &l->buffer_size, buf_size);
     if (!l->buffer) {
         av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");