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Comment by eperot | Hacker News Reader

Any reason why you wouldn't use gVisor's bwrap interface yet? We're working on it precisely to make DIY sandboxing on Linux as easy as possible in order to get Linux-sandboxing-at-home to mature beyond the current syscall-filter-and-namespaces duct tape stage, so I'm curious to know what you'd like to see.

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It just didn't seem fully baked yet, the 'do' subcommand works fine while the 'bwrap' alias has this problem: `bash: cannot set terminal process group (1): Not a tty`. When executing 'bash -li'. Also the EROFS feature of 'do' should probably be included in 'bwrap', it can be useful. Include overlay options.

Also some things you can do to make gvisor better are Wayland passthrough, vulkan support (or virtio native context). Being able to get gvisor to populate a network interface inside itself through a 'passt' (or 'containers/gvisor-tap-vsock') socket on the host would also be ergonomic. All of those are available on 'muvm' (based on libkrun) which if you have the time to set up is the next step in DIY sandboxing of graphical apps as well. See: <https://git.clan.lol/clan/munix>

Thanks. We're working on rootless network setup to make `runsc do --rootless` work with networking enabled when `passt` is installed right now. See issue #13337 (yes that's a cool issue number) which should unblock this.

The tty issue is known, should be fixed soon too, though contributions welcome as it sounds like it should be simple fix and we love more contributions :)

FWIW, X11 apps work well, I have a personal hacky project in which I've been running Librewolf in gVisor, with the window being reflected as a native Wayland window. It uses `Xvfb -fbdir` aimed at a bound tmpfs mount to get a shared memory region containing the window's pixel data which can be read directly from out of the sandbox, has Pulseaudio audio passthrough, and a socket server passing through mouse/keyboard events to make the window interactive. Works smoothly even for YouTube playback, and I successfully played a game of Unreal Tournament 2004 at 24fps in it, with no noticeable mouse/keyboard latency :) We're basically making baby steps to get there less hackily.

Thanks for the feedback!

That's good to hear! Hopefully the passt approach you are pursuing will include the ability to use an existing passt socket and not just launch one for you.

Wayland is tricky because there are memory buffers being shared between the compositor and the client. crosvm (also by google) adopted 2 custom solutions to it of which one got merged into mainline.

Achieving audio passthrough is trivial as it's just a unix socket. `-host-uds=all`

That's the approach I initially took, but experienced some combination of noticeable stuttering and latency regardless of which buffering strategy I tried... Had to switch to a shared memory ring buffer, along with some adaptive playback speed shenanigans (sometimes imperceptibly speeding up playback when falling behind production of audio samples, sometimes imperceptibly slowing down when there's less than a few milliseconds' worth of samples left in the ringbuffer), in order to achieve actually-gapless playback.

There is something wrong with your setup.

I just tried:

    bwrap ... --ro-bind /run/user/1000/pipewire-0 /run/user/1000/pipewire-0 ... -- runsc ... do ... -- mpv podcast.mp3

Flawless playback. I think it's a default pipewire configuration.

Ah, I see the distinction. In my case, I was using the PulseAudio client+server with a network sink running in-sandbox, producing a set of audio samples that are then replayed by a PulseAudio client in the out-of-sandbox Rust application receiving these samples. Exposing the socket directly to the sandbox is dangerous, e.g. it would let the sandbox record the host's microphone directly.

My goal was for the sandbox to only have access to a single dumb playback sink and no other access by default, and to gate any further access (e.g. microphone access) in something the out-of-sandbox software can catch and ask the user about before it is granted to the sandbox.

> Exposing the socket directly to the sandbox is dangerous, e.g. it would let the sandbox record the host's microphone directly.

libpipewire-module-pipe-tunnel

also: <https://gitlab.freedesktop.org/pipewire/pipewire/-/merge_req...>

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