[FFmpeg-devel] [PATCH] avformat/mov: perform sanity checks for heif before index building

[James Almer]

On 1/8/2025 5:31 PM, Michael Niedermayer wrote:
> Fixes: undefined NULL pointer use
> Fixes: clusterfuzz-testcase-minimized-audio_decoder_fuzzer-6363211175493632
> 
> This performs equivalent sanity checks as are done in mov_read_trak()
> before mov_build_index()
> 
> Reported-by: Dale Curtis <dalecurtis at chromium.org>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>   libavformat/mov.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 56f732bfcfb..33823b98b2f 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -10411,6 +10411,10 @@ static int mov_parse_heif_items(AVFormatContext *s)
>           if (sc->sample_count != 1 || sc->chunk_count != 1)
>               return AVERROR_INVALIDDATA;
>   
> +            /* sanity checks */
> +        if (!sc->stts_count || !sc->stsc_count)
> +            return AVERROR_INVALIDDATA;

Not against it, but I'd like to check the sample. If the AVStream here 
is not NULL, both of those should be 1.

> +
>           sc->sample_sizes[0]  = item->extent_length;
>           sc->chunk_offsets[0] = item->extent_offset + offset;
>   

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