Authorized clients

[Martin Peres]

On 07/01/2014 20:53, Daniel Stone wrote:
> Hi,
>
> On 7 January 2014 19:22, Maarten Baert <maarten-baert at hotmail.com> wrote:
>> @Martin Peres: Your ideas are nice in theory, but as Sebastian Wick already
>> said, it is just not practical.
>>
>> If you want a specific example, I have one:
>> https://github.com/MaartenBaert/ssr
>> The sole purpose of this application is to record the screen (i.e. take 30
>> screenshots per second). People are using this - the latest version has been
>> installed about 13.000 times on Ubuntu alone (and that number is still
>> growing). I know that's not a lot in the big picture, but clearly it is not
>> an 'extremely rare case'.
>>
>> I really want to add Wayland support to this application. In fact that's why
>> I'm here, discussing an API to authenticate my program so I can actually
>> start to think about adding Wayland support. Your answer seems to be that
>> the user should continuously hold down a button on their keyboard in order
>> to record their screen. That's just not acceptable. I will simply have to
>> tell users to disable the security features in Weston completely so they can
>> use my application - and most of them will probably have no problem with
>> that, because the average user doesn't care about security, especially when
>> it is something trivial like the ability to take screenshots. Seriously - a
>> rogue application can install a keylogger, steal my saved passwords and
>> browser cookies, ssh and pgp keys, delete all my files and even my backups,
>> but luckily it can't take screenshots! I do not want to tell users to
>> disable security features, but if these features make it completely
>> impossible for an application to function, then I have no choice.
> Alternately, you can just have a hotkey which triggers video
> recording, or since your compositor's likely to be the one launching
> your screen recorder, it already knows that the client is trusted to,
> well, record the screen.

Right, an application that wants to capture the screen continuously is
a video recording app and should be treated as such by the compositor.

It is OK if a screenshot application forces a copy of the framebuffer but
do we really want video recording to trigger 30 copies of the framebuffer
per second or do we want to use DMA-buf to the video-recording tool
so as it can use sw or hw compression techniques?

This isn't a security question, this is just getting rid of this X11 idea
that video grabbing means taking snapshots several times per second
without synchronization.

My point is that the screenshot interface shouldn't be used for video
recording.