[FFmpeg-devel] [PATCH 1/3] avformat/dashdec: fail on probing non mpd file extension

[Tobias Rapp]

On 09/05/2023 08:19, Anton Khirnov wrote:

> Quoting Michael Niedermayer (2023-05-09 00:35:08)
>> On Mon, May 08, 2023 at 04:05:40PM +0200, Tobias Rapp wrote:
>>> [...]
>>> DASH is usually transferred over HTTP where file extensions are of minor
>>> interest, the relevant type information is in the Mime-Type header.
>> would anyone be opposed to return 0 from dash_probe() when
>> both the mime_type and the extension are wrong ?
> I would.
>
> probe() is for probing, not implementing security policies. IMO trying
> to fix security issues at the wrong layer will only lead to more
> confusion, more complexity, and LESS security.

I agree that probing should be unrelated to the actual format selection 
policy.

>> example: a crafted image.jpeg uploaded somewhere is played as dash.
>> or am i missing something that would stop that ?
The player application could exclude the dash format (and other playlist 
formats) from the format_whitelist I guess?

The alternative for the player application if it doesn't need to depend 
on the system installation of FFmpeg libraries would be to exclude 
unwanted formats at compilation time.

Regards, Tobias