From 1f6fcc64179377114b4ecc3b9f63bd5774a64edf Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Sat, 30 Sep 2023 00:51:29 +0200
Subject: [PATCH] avformat/dxa: Adjust order of operations around block
align

Fixes:
51896/clusterfuzz-testcase-minimized-ffmpeg_dem_DXA_fuzzer-5730576523198464
Fixes: signed integer overflow: 2147483566 + 82 cannot be represented in
type 'int'

Found-by: continuous fuzzing process
https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 50d8e4f27398fd5778485a827d7a2817921f8540)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/dxa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/dxa.c b/libavformat/dxa.c
index 298cda0..e46c9b0 100644
--- a/libavformat/dxa.c
+++ b/libavformat/dxa.c
@@ -120,7 +120,7 @@ static int dxa_read_header(AVFormatContext *s)
         }
         c->bpc = (fsize + c->frames - 1) / c->frames;
         if(ast->codecpar->block_align)
-            c->bpc = ((c->bpc + ast->codecpar->block_align - 1) / ast->codecpar->block_align) * ast->codecpar->block_align;
+	    c->bpc = ((c->bpc - 1 + ast->codecpar->block_align) / ast->codecpar->block_align) * ast->codecpar->block_align;
         c->bytes_left = fsize;
         c->wavpos = avio_tell(pb);
         avio_seek(pb, c->vidpos, SEEK_SET);
-- 
2.41.0

