From: Michael Niedermayer <michael@niedermayer.cc>
Date: Mon, 15 Apr 2019 00:01:56 +0000 (+0200)
Subject: avcodec/dsicinvideo: check the amount decoded by cin_decode_huffman()
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=fee666104519ec7889ec3242404857bed7598a36;p=ffmpeg

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 37175d67b2e..d422df068df 100644
--- 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,