Tuple Launch

Use the following link to download the toolchain for this project:

https://ziglang.org/builds/zig-linux-x86_64-0.10.0-dev.2674+d980c6a38.tar.xz

Download/extract the archve and run zig build with the resulting zig executable.

This will generate executables in the zig-out directory which will include:

• the signing executable for generating new keys/signing and verifying signatures.
• the tuple-launch and tuple-flatpak-launch executables which are used by Tuple uses during its launch process.

Tuple Launch Process

Tuple requires privileged access that the flatpak portal doesn't provide. To accomodate this, Tuple prompts the user to install a privileged daemon.

The privileged daemon is split into 2 static executables:

1. tuple-launch
2. tuple-flatpak-launch

tuple-launch is what the user installs to their host filesystem. It gains root access via SUID. It's only job is to find, verify and launch tuple-flatpak-launch.

tuple-flatpak-launch remains inside the Tuple flatpak so it will be updated alongside Tuple. Splitting the daemon up like this means the user won't need to re-install the privileged daemon every time it changes.

Since tuple-flatpak-launch can change, it's important that tuple-launch verifies it came from Tuple. We do this with an ed25519 signature. This verification is made easier because tuple-flatpak-launch is a static executable. This makes it trival load it into memory, verify it, then execute it in-place. This eliminates the disk as an attack vector.