From 18193cfadbb5c7207fb84d682cc0614d7bf211e7 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Thu, 23 May 2024 01:43:42 +0200
Subject: [PATCH] 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@niedermayer.cc>
(cherry picked from commit 2f04cb673cb394b6e1cda160af8faa733b62bae2)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/ac4dec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/ac4dec.c b/libavformat/ac4dec.c
index 71950f52dc..2952036c25 100644
--- a/libavformat/ac4dec.c
+++ b/libavformat/ac4dec.c
@@ -42,6 +42,8 @@ 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;