[FFmpeg-cvslog] avformat/rmdec: Check codec_length without overflow

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Mon Feb 15 20:52:17 2021 +0100| [aff56aa499706f836f9d609a9c7c98ef452f7a8b] | committer: Michael Niedermayer

avformat/rmdec: Check codec_length without overflow

Fixes: signed integer overflow: 2147483647 + 64 cannot be represented in type 'int'
Fixes: 30333/clusterfuzz-testcase-minimized-ffmpeg_dem_RM_fuzzer-5175286983426048

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit d558c9f2375fd2136d20422cb1119cfbf872abeb)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=aff56aa499706f836f9d609a9c7c98ef452f7a8b
---

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

diff --git a/libavformat/rmdec.c b/libavformat/rmdec.c
index e8f2657621..49048ac4eb 100644
--- a/libavformat/rmdec.c
+++ b/libavformat/rmdec.c
@@ -220,7 +220,7 @@ static int rm_read_audio_stream_info(AVFormatContext *s, AVIOContext *pb,
                 if (version == 5)
                     avio_r8(pb);
                 codecdata_length = avio_rb32(pb);
-                if(codecdata_length + AV_INPUT_BUFFER_PADDING_SIZE <= (unsigned)codecdata_length){
+                if((unsigned)codecdata_length > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE){
                     av_log(s, AV_LOG_ERROR, "codecdata_length too large\n");
                     return -1;
                 }