SO_PEERCRED and pidfd

[Simon Ser]

Hi all,

I'm a Wayland developer and I've been working on protocol security,
which involves identifying the process on the other end of a Unix
socket [1]. This is already done by e.g. D-Bus via the PID, however
this is racy [2].

Getting the PID is done via SO_PEERCRED. Would there be interest in
adding a way to get a pidfd out of a Unix socket to fix the race?

Thanks,

Simon Ser

[1]: https://gitlab.freedesktop.org/wayland/weston/issues/206
[2]: https://github.com/flatpak/flatpak/issues/2995