Linux Hello

Face unlock for KDE Plasma, sudo and polkit.

• Unlocks the Plasma lock screen, approves polkit prompts and sudo with your face.
• Admin prompts and sudo scan only after you press Enter, so other programs can't use your face.
• Prefers the infrared camera and switches its IR light on by itself.
• Set up in System Settings. No terminal, no config files.
• Your password always keeps working.

Requirements

• KDE Plasma 6 on Wayland. Face unlock on the lock screen needs Plasma 6.8 or later. X11 is not supported: any program there can read your keys.
• A camera. An infrared (Windows Hello) camera works in the dark and is much harder to fool.

Install

There are no release packages yet. Build one from this repository:

# Arch, CachyOS
cd packaging/arch && makepkg -si

Fedora (packaging/fedora/linux-hello.spec) and Debian/Kubuntu (debian/) packages build the same way; see .github/workflows/check.yml for the steps.

Then open System Settings > Security & Privacy > Face Unlock.

Uninstall

Remove the package. Linux Hello undoes its PAM changes before it goes. Face models stay in /var/lib/linux-hello until you delete them.

Command line

linux-hello-cli status        # what is set up
linux-hello-cli add           # add your face
linux-hello-cli enable sudo   # lock-screen, admin, sudo, login
linux-hello-cli doctor        # find problems

Build from source

Needs a C++20 compiler, meson, ninja, cmake, extra-cmake-modules, Qt 6, KDE Frameworks 6 (KCMUtils, Kirigami, I18n, Config, CoreAddons) and the headers for pam, libevdev, libsystemd and inih.

tools/build_runtime.sh --outdir build-runtime
meson setup build -Dbundled_python_dir="$PWD/build-runtime/linux-hello-runtime"
ninja -C build && sudo ninja -C build install

cmake -B build-kcm -S kcm -DCMAKE_INSTALL_PREFIX=/usr
cmake --build build-kcm && sudo cmake --install build-kcm

build_runtime.sh downloads a Python runtime with OpenCV and dlib, pinned in tools/runtime-manifest.json. Without -Dbundled_python_dir, the system Python is used and needs OpenCV, dlib, numpy and dbus-fast.

Remove a source install with sudo tools/uninstall.sh.

Hardware notes

• IR light stays off: run sudo linux-hello-cli emitter search.
• ASUS laptops with Sonix IR cameras (3277:0018): the IR light follows the proximity sensor. Do not run emitter search or linux-enable-ir-emitter on these; it can hang the USB bus (boltgolt/howdy#1109).
• SELinux (Fedora): if the camera fails, check the audit log for linux-hello-daemon.
• Keyboard remappers (keyd, kanata, Steam Input): the Enter for sudo and admin prompts is not seen, so those fall back to your password.

Credits

Remake of Howdy by boltgolt, MIT licensed; see NOTICE. Includes #1088 by haleelrah (recognition backends) and #1125 by qilsklo (WebAuthn). IR light control follows linux-enable-ir-emitter.

License

GPL-3.0. See LICENSE and NOTICE.