Address findings from second triple audit (quality, performance, security):
- Wrap PAM CString password in Zeroizing<CString> to wipe on drop (S-H1)
- Add check_account() for pam_acct_mgmt after fingerprint unlock,
with resume_async() to restart FP on transient failure (S-M1)
- 30s PAM timeout with generation counter to prevent stale result
interference from parallel auth attempts (S-M3)
- Downscale wallpaper to max 1920px before GPU blur, reducing work
by ~4x on 4K wallpapers (P-M1)
- exit(1) instead of return on no-monitor after lock.lock() (Q-2.1)
Wallpaper is installed by moonarch to /usr/share/moonarch/wallpaper.jpg.
Embedding a 374K JPEG in the binary was redundant. Without a wallpaper
file, GTK background color (Catppuccin Mocha base) shows through.
Close the only exploitable auth bypass: validate VerifyStatus signal sender
against fprintd's unique bus name. Fix fingerprint D-Bus lifecycle so devices
are properly released on verify-match and async restarts check the running
flag between awaits.
Security: num_msg guard in PAM callback, symlink rejection for background_path,
peek icon disabled, TOML parse errors logged, panic hook before logging.
Performance: blur and avatar textures cached across monitors, release profile
with LTO/strip.
Gaussian blur applied at texture load time when `background_blur` is
set in moonlock.toml. Refactored wallpaper loading from per-window
Picture::for_filename() to shared gdk::Texture pattern (matching
moonset/moongreet), avoiding redundant JPEG decoding on multi-monitor.
