baijia-suo — A Secure Wayland Screen Locker

A screen locker has one job, and nobody thinks about it until it fails open. The old X11 lockers don't carry over to Wayland, and a locker that crashes, leaks the password out of memory, or lets you attach a debugger to it has failed at that job. 百家锁 means the lock of a hundred families. This one tries to take the boundary seriously.

• PAM runs in a separate child process, not in the one talking to the compositor. A memory disclosure in the UI half doesn't give up the password.
• Password buffers are page-aligned and mlocked so they never hit swap, and get zeroized after use. The auth child is pinned in RAM with mlockall.
• PR_SET_DUMPABLE turns off core dumps and refuses non-root ptrace. You can't attach to the running locker or dump it.
• Built on ext-session-lock-v1. If the locker process dies the session stays locked. The failure mode is being locked out, which is the right one.
• Ported 66 animations from xlockmore and xscreensaver, each file keeping its original author's permissive licence. That is the part this started as: those screensavers are decades of well-loved work that only ran under X11, and Wayland was quietly going to strand them. Carrying them forward needed a locker worth trusting to run them.
• Backgrounds are RGBA and the typing indicator has several styles, oscilloscope among them. Configure by TOML or CLI flag.

• A locker that works, with a man page, shell completions and distro packaging.
• Fail-closed by construction. What keeps the session locked is the protocol, not the process staying up.
• Public, with a SECURITY.md that says plainly it hasn't been independently audited.
• 66 animations that would otherwise have died with X11 now run on a modern compositor, with their authorship and licences intact.