[FFmpeg-cvslog] avformat/id3v2: Check against max compression ratio before allocation

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov 28 23:43:23 2020 +0100| [c48110a4a4b3ba87cb3ffe66753bff13c618a04d] | committer: Michael Niedermayer

avformat/id3v2: Check against max compression ratio before allocation

Fixes: Timeout (>10sec -> 12ms)
Fixes: 27612/clusterfuzz-testcase-minimized-ffmpeg_dem_PCM_S24BE_fuzzer-6605893000757248

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=c48110a4a4b3ba87cb3ffe66753bff13c618a04d
---

 libavformat/id3v2.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c
index 336a3964de..97f6cc8a68 100644
--- a/libavformat/id3v2.c
+++ b/libavformat/id3v2.c
@@ -995,6 +995,8 @@ static void id3v2_parse(AVIOContext *pb, AVDictionary **metadata,
 
                     if (tlen <= 0)
                         goto seek;
+                    if (dlen / 32768 > tlen)
+                        goto seek;
 
                     av_fast_malloc(&uncompressed_buffer, &uncompressed_buffer_size, dlen);
                     if (!uncompressed_buffer) {