[FFmpeg-devel] [PATCH 2/5] avformat/mxfdec: Reorder elements of expression in bisect loop

[Tomas Härdin]

ons 2024-07-17 klockan 13:27 +0200 skrev Michael Niedermayer:
> Fixes: signed integer overflow: 9223372036854775807 - -1 cannot be
> represented in type 'long'
> Fixes: 68578/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-
> 6032171648221184
> 
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavformat/mxfdec.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> index a5863445ab5..af0c8a31007 100644
> --- a/libavformat/mxfdec.c
> +++ b/libavformat/mxfdec.c
> @@ -3821,8 +3821,7 @@ static int
> mxf_get_next_track_edit_unit(MXFContext *mxf, MXFTrack *track, int64_
>  
>      a = -1;
>      b = track->original_duration;
> -
> -    while (b - a > 1) {
> +    while (b - 1 > a) {
>          m = (a + b) >> 1;
>          if (mxf_edit_unit_absolute_offset(mxf, t, m, track-
> >edit_rate, NULL, &offset, NULL, 0) < 0)
>              return -1;

Should be OK since b is always >= 0.

/Tomas