[FFmpeg-cvslog] avformat/wavdec: More complete size check in find_guid()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov 14 22:13:52 2020 +0100| [a207df2acb92d6366ab2f0f18ba35709066b8eec] | committer: Michael Niedermayer

avformat/wavdec: More complete size check in find_guid()

Fixes: signed integer overflow: 9223372036854775807 + 8 cannot be represented in type 'long'
Fixes: 27341/clusterfuzz-testcase-minimized-ffmpeg_dem_W64_fuzzer-5442833206738944

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a207df2acb92d6366ab2f0f18ba35709066b8eec
---

 libavformat/wavdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/wavdec.c b/libavformat/wavdec.c
index a81f2c7a67..df6030a42d 100644
--- a/libavformat/wavdec.c
+++ b/libavformat/wavdec.c
@@ -666,7 +666,7 @@ static int64_t find_guid(AVIOContext *pb, const uint8_t guid1[16])
     while (!avio_feof(pb)) {
         avio_read(pb, guid, 16);
         size = avio_rl64(pb);
-        if (size <= 24)
+        if (size <= 24 || size > INT64_MAX - 8)
             return AVERROR_INVALIDDATA;
         if (!memcmp(guid, guid1, 16))
             return size;