[FFmpeg-devel] [PATCH 3/5] avformat/asfdec_f: Check name_len for overflow

Michael Niedermayer michael at niedermayer.cc
Thu Oct 15 23:32:30 EEST 2020


Fixes: signed integer overflow: -1172299744 * 2 cannot be represented in type 'int'
Fixes: 26258/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5672758488596480

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/asfdec_f.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index 103155e9e7..ff9107d73f 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -769,6 +769,8 @@ static int asf_read_marker(AVFormatContext *s, int64_t size)
         avio_rl32(pb);             // send time
         avio_rl32(pb);             // flags
         name_len = avio_rl32(pb);  // name length
+        if ((unsigned)name_len > INT_MAX / 2)
+            return AVERROR_INVALIDDATA;
         if ((ret = avio_get_str16le(pb, name_len * 2, name,
                                     sizeof(name))) < name_len)
             avio_skip(pb, name_len - ret);
-- 
2.17.1



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