avformat/avidec: Use 64bit in get_duration()

Fixes: signed integer overflow: 2147483424 + 8224 cannot be represented in type 'int'
Fixes: 29619/clusterfuzz-testcase-minimized-ffmpeg_dem_AVI_fuzzer-5191424373030912
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 79000f3e819df7a8d9e98db9f92b4b9d287264d1..547eb63b1b92084a375d8096daa1ccba8d1214ce 100644 (file)
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -135,7 +135,7 @@ static inline int get_duration(AVIStream *ast, int len)
     if (ast->sample_size)
         return len;
     else if (ast->dshow_block_align)
-        return (len + ast->dshow_block_align - 1) / ast->dshow_block_align;
+        return (len + (int64_t)ast->dshow_block_align - 1) / ast->dshow_block_align;
     else
         return 1;
 }