avcodec/dsicinvideo: check the amount decoded by cin_decode_huffman()

Fixes: Timeout (158sec -> 36sec)
Fixes: 14214/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DSICINVIDEO_fuzzer-5633569034076160
This is untested with valid cin files as none of the files i found cover the changed
codepath

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

diff --git a/libavcodec/dsicinvideo.c b/libavcodec/dsicinvideo.c
index 37175d67b2e9528646644653471458412fdaf4dc..d422df068df34c03fc43786872b65dae6a5fd9e8 100644 (file)
--- a/libavcodec/dsicinvideo.c
+++ b/libavcodec/dsicinvideo.c
@@ -266,8 +266,11 @@ static int cinvideo_decode_frame(AVCodecContext *avctx,
                              cin->bitmap_table[CIN_CUR_BMP], cin->bitmap_size);
         break;
     case 37:
-        cin_decode_huffman(buf, bitmap_frame_size,
+        res = cin_decode_huffman(buf, bitmap_frame_size,
                            cin->bitmap_table[CIN_CUR_BMP], cin->bitmap_size);
+
+        if (cin->bitmap_size - avctx->discard_damaged_percentage*cin->bitmap_size/100 > res)
+            return AVERROR_INVALIDDATA;
         break;
     case 38:
         res = cin_decode_lzss(buf, bitmap_frame_size,