[FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[Kacper Michajlow]

On Wed, 23 Jul 2025 at 10:43, Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> Fixes: use of uninitialized memory
> Fixes: 403675492/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_fuzzer-4754281823797248
>
> 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/asfdec_f.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
> index ea6e8ef4f3a..10f5dea57c3 100644
> --- a/libavformat/asfdec_f.c
> +++ b/libavformat/asfdec_f.c
> @@ -241,7 +241,9 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int
>          avio_get_str16le(s->pb, len, value, 2 * len + 1);
>          break;
>      case -1: // ASCI
> -        avio_read(s->pb, value, len);
> +       ;int ret = ffio_read_size(s->pb, value, len);

stray ;

> +        if (ret < 0)
> +            goto finish;
>          value[len]=0;
>          break;
>      case ASF_BYTE_ARRAY:
> --
> 2.49.0
>
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