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>
This commit is contained in:
Michael Niedermayer 2023-09-30 00:51:29 +02:00
parent d973fcbcc2
commit 50d8e4f273
No known key found for this signature in database
GPG Key ID: B18E8928B3948D64

View File

@ -123,7 +123,7 @@ 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);