[FFmpeg-cvslog] avformat/ac4dec: Check remaining space in ac4_probe()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu May 23 01:43:42 2024 +0200| [2f04cb673cb394b6e1cda160af8faa733b62bae2] | committer: Michael Niedermayer

avformat/ac4dec: Check remaining space in ac4_probe()

Fixes: CID1538298 Untrusted loop bound
Fixes: undefined behavior

Sponsored-by: Sovereign Tech Fund
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2f04cb673cb394b6e1cda160af8faa733b62bae2
---

 libavformat/ac4dec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/ac4dec.c b/libavformat/ac4dec.c
index f647f557cc..dc6638de3a 100644
--- a/libavformat/ac4dec.c
+++ b/libavformat/ac4dec.c
@@ -43,6 +43,8 @@ static int ac4_probe(const AVProbeData *p)
             size += 4;
             if (buf[1] == 0x41)
                 size += 2;
+            if (left < size)
+                break;
             max_frames++;
             left -= size;
             buf += size;