> For instance, once any client has any kind of X11 access they can snope any kind of keyboard events, including your password at the unlock screen
Is this true? Can you provide a proof of concept that can attack xscreensaver in this way? I was not under the impression that xscreensaver in particular is vulnerable to such an attack. I would like to see the code.
> Is raw audio output necessary? Why does not pulseaudio work?
Funny story, I have never gotten pulseaudio to successfully play any audio. Every so often I read somewhere that pulse makes audio scenario xyz really easy. I try it out and I cannot get any audio samples out to the sound card, period. The only other time I hear about pulse is when I'm telling people to kill it, which ends up fixing all their audio problems. So no thanks to pulse.
Meanwhile I can't help but think that Unix already has a security model for talking to devices, it is called enforcing security at open(2). What is bad about letting an app talk to alsa if it needs audio? If you can provide an example, is that not a privilege escalation in alsa that should be fixed?
It just strikes me that your article here is a technical solution in search of a problem. Apple did sandboxing so it must be right, huh?
> What is bad about letting an app talk to alsa if it needs audio?
In general, audio output is not really a problem. However, input is much more problematic. For instance, your app could listen on your microphones and send the data over the network. Permissions on the audio device doesn't work here, especially considering that such permissions are per-user, not per-app.
Overall the security model in unix is pretty shit for the desktop. Its all about protecting root or other users from the user. However, if I'm on a single user laptop that is not overly interesting. The much more interesting part is protecting the user from the system. For instance by being able to run a game without it ever having the possibility of reading my personal email or web history.
Is this true? Can you provide a proof of concept that can attack xscreensaver in this way? I was not under the impression that xscreensaver in particular is vulnerable to such an attack. I would like to see the code.
> Is raw audio output necessary? Why does not pulseaudio work?
Funny story, I have never gotten pulseaudio to successfully play any audio. Every so often I read somewhere that pulse makes audio scenario xyz really easy. I try it out and I cannot get any audio samples out to the sound card, period. The only other time I hear about pulse is when I'm telling people to kill it, which ends up fixing all their audio problems. So no thanks to pulse.
Meanwhile I can't help but think that Unix already has a security model for talking to devices, it is called enforcing security at open(2). What is bad about letting an app talk to alsa if it needs audio? If you can provide an example, is that not a privilege escalation in alsa that should be fixed?
It just strikes me that your article here is a technical solution in search of a problem. Apple did sandboxing so it must be right, huh?