System Extensions from Flatpak

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2024-05-08 09:30:05

An impediment to that is the intrusiveness to test out new features as they are developed. If only we had a Flatpak which you could install to test things right away.

One major hurdle is how much information a profiler needs to be useful. The first obvious “impossible to sandbox” API you run into is the perf subsystem. It provides information about all processes running on the system and their memory mappings which would make snooping on other processes trivial. Both perf and ptrace are disabled in the Flatpak sandbox.

After that, you still need unredacted access to the kernel symbols and their address mappings (kallsyms). You also need to be in a PID namespaces that allows you to see all the processes running on the system and their associated memory mappings which essentially means CAP_SYS_ADMIN.

Years ago, portable services were introduced into systemd through portablectl. I had high-hopes for this because it meant that I could perhaps ship a squashfs and inject it as a transient service on the host.