[FFmpeg-devel] [RFC][PATCH] configure: Disable unsafe demuxers by default

[Paul B Mahol]

On 5/10/18, Derek Buitenhuis <derek.buitenhuis at gmail.com> wrote:
> These demuxers have probes that mainly probe based on file extension,
> and map to codec IDs that render text as video. The result is that
> ffmpeg will, by default, happily render, for example, .txt files
> as images. This is not exactly a good security practice, an only
> makes it easier for potential attackers to gain the contents of
> system files.
>
> Disable building these by default.
>
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> ---
> I've been hard disabling these at $dayjob for a long time, after some
> "interesting" upload attempts, but it should probably be done for
> everyone.
>
> I'm not overly attached implementaion details like the option name
> or whether it's done at build time ot runtime, but I think the concept
> of "don't render arbitrary system text files" is an important one.
> ---
>  Changelog     | 1 +
>  configure     | 7 +++++++
>  tests/fate.sh | 1 +
>  3 files changed, 9 insertions(+)
>
> diff --git a/Changelog b/Changelog
> index d442ced..e3f8e83 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -6,6 +6,7 @@ version <next>:
>  - tmix filter
>  - amplify filter
>  - fftdnoiz filter
> +- unsafe demuxers that render text files now disabled by default
>

Against.