[FFmpeg-devel] [PATCH 1/6] avcodec/shorten: Check verbatim length

Michael Niedermayer michael at niedermayer.cc
Mon Aug 13 03:24:18 EEST 2018


Fixes: Timeout
Fixes: 9252/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SHORTEN_fuzzer-5780720709533696

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/shorten.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index 0f491090fd..9094d3fc55 100644
--- a/libavcodec/shorten.c
+++ b/libavcodec/shorten.c
@@ -623,6 +623,11 @@ static int shorten_decode_frame(AVCodecContext *avctx, void *data,
             switch (cmd) {
             case FN_VERBATIM:
                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
+                if (len < 0 || len > get_bits_left(&s->gb)) {
+                    av_log(avctx, AV_LOG_ERROR, "verbatim length %d invalid\n",
+                           len);
+                    return AVERROR_INVALIDDATA;
+                }
                 while (len--)
                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
                 break;
-- 
2.18.0



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