Switching to ALSA

[Patrick]

@FrozenCat

On Gentoo Linux, making a system free of pulseaudio and systemd is easy. You could also build a binary distribution on top of Gentoo Linux.

Mixing porting to another base distribution (which is a very complex topic) on which Whonix is based on with “Switching to ALSA” (which looks comparatively a lot easier) is too much off-topic for this forum topic. Please create a new forum thread for that if needed.

As for porting to another base distribution and (Hardened) Gentoo, see also the following development notes:

• Gentoo / Hardened Gentoo
• Criteria for Choosing a Base Distribution
• ToDo List for Porting to another Base Distribution
• and Dev/Operating System page generally

@FrozenCat

Or, you can install libapulse.

This seems cool at first sight. Quote:

Debian -- Details of package apulse in buster

PulseAudio emulation for ALSA

The program provides an alternative partial implementation of the PulseAudio API. It consists of a loader script and a number of shared libraries with the same names as from original PulseAudio, so applications could dynamically load them and think they are talking to PulseAudio. Internally, no separate sound mixing daemon is used. Instead, apulse relies on ALSA’s dmix, dsnoop, and plug plugins to handle multiple sound sources and capture streams running at the same time. dmix plugin muxes multiple playback streams; dsnoop plugin allow multiple applications to capture from a single microphone; and plug plugin transparently converts audio between various sample formats, sample rates and channel numbers.

What do you think?

This might help with getting Tor Browser to work with ALSA (without recompilation)? (That is, if Tor Browser currently has a hard dependency on PulseAudio for sound which I am not sure yet.)

@FrozenCat

If you can’t maintain a binary distribution on top of Gentoo, you don’t have much resource unfortunately.

Indeed.

@FrozenCat

Another alternative is to compile torbrowser deb package yourself.

We don’t have human resources for that either.
Nobody managed to create one yet even though a very popular request:

• Make a deb of the Torbrowser and add to repository [archive]
• Get TorBrowser in Debian [archive]

Related:
Tor Browser Update: Technical Details

@madaidan

@Patrick

Any reference showing that ALSA can be sandboxed while pulseaudio cannot be sandboxed?

It’s only PulseAudio that adds the functionality to escape sandboxes. It doesn’t exist in ALSA as it’s rather bare bones.

https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/Developer/AccessControl/

Alright. Some issues mentioned on that link (such as Snoop on other application's audio or Have unmediated access to the microphone) may still be issues with ALSA?

However, I can see the general attack surface reduction argument.

Load and unload server modules, including network ones

@madaidan

this will still serve as general attack surface reduction - no point in having a large amount of code that’s not useful for us.

Makes sense.

Conclusion:

• Porting from PulseAudio to ALSA is worthwhile. Help welcome. Let me know which packages to remove/add and/or send pull request for anon-meta-packages.
  • Maybe apulse can help.
  • We need audio support in Tor Browser.
    • EDIT: maybe possible thanks to apulse torbrowser
  • VLC is not important enough for installation by default if it was in theory an obstacle for porting from PulseAudio to ALSA.
• Porting from PulseAudio to ALSA is however is not a blocker for System-wide sandboxing framework - sandbox-app-launcher.