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[FFmpeg-devel,5/6] avformat/dxa: Adjust order of operations around block align

Message ID 20230929232001.23197-5-michael@niedermayer.cc
State Accepted
Commit 50d8e4f27398fd5778485a827d7a2817921f8540
Headers show
Series [FFmpeg-devel,1/6] avformat/avidec: support huge durations | expand

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Commit Message

Michael Niedermayer Sept. 29, 2023, 11:20 p.m. UTC 
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>
---
 libavformat/dxa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/libavformat/dxa.c b/libavformat/dxa.c
index 474b85270ae..b4d9d005290 100644
--- a/libavformat/dxa.c
+++ b/libavformat/dxa.c
@@ -122,7 +122,7 @@  static int dxa_read_header(AVFormatContext *s)
         if(ast->codecpar->block_align) {
             if (c->bpc > INT_MAX - ast->codecpar->block_align + 1)
                 return AVERROR_INVALIDDATA;
-            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);