[FFmpeg-devel] [PATCH 3/7] avutil/parseutils: Check sign in av_parse_time()

[Marton Balint]

On Thu, 14 Jan 2021, Michael Niedermayer wrote:

> Fixes: signed integer overflow: -9223372053736 * 1000000 cannot be represented in type 'long'
> Fixes: 26910/clusterfuzz-testcase-minimized-ffmpeg_dem_CONCAT_fuzzer-6607924558430208
>
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
> libavutil/parseutils.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavutil/parseutils.c b/libavutil/parseutils.c
> index 167e822648..6161f4ac95 100644
> --- a/libavutil/parseutils.c
> +++ b/libavutil/parseutils.c
> @@ -736,7 +736,7 @@ int av_parse_time(int64_t *timeval, const char *timestr, int duration)
>     if (*q)
>         return AVERROR(EINVAL);
> 
> -    if (INT64_MAX / suffix < t)
> +    if (t < 0 || INT64_MAX / suffix < t)

This does not look right, because a negative t can mean a date before 
1970.

Regards,
Marton

>         return AVERROR(ERANGE);
>     t *= suffix;
>     if (INT64_MAX - microseconds < t)
> -- 
> 2.17.1
>
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