Watch

Linux fingerprint sensor daemon for QTEE devices

C++ 89.2%
Shell 10.8%

Find a file

Repository files (latest commit first)
Filename	Latest commit message	Latest commit date
Jorijn van der Graaf 51f476e596 the agent prints the daemon's version, from the constant the packaging reads The agent answered --version with "fingerprintd-agent 0.2.2", the string it was written with, while the daemon's constant went 0.2.3, 0.2.4, 0.2.5: the subpackage carried the package's version and reported another. The constant moves from main.cpp into the module both products import, with its note on what a bump publishes; the two scripts that derive pkgver from it, the APKBUILD's header and the CI comment name the new file. The APKBUILD's own pkgver stays a hand-kept copy, which a bump changes too.		2026-10-14 01:37:38 +02:00
.forgejo/workflows	the agent prints the daemon's version, from the constant the packaging reads	2026-10-14 01:37:38 +02:00
implementations	the agent prints the daemon's version, from the constant the packaging reads	2026-10-14 01:37:38 +02:00
interfaces	the agent prints the daemon's version, from the constant the packaging reads	2026-10-14 01:37:38 +02:00
packaging	the agent prints the daemon's version, from the constant the packaging reads	2026-10-14 01:37:38 +02:00
tests	a template no name accounts for is removed, not kept in the way	2026-10-14 01:37:38 +02:00
.gitignore	Initial commit: the gpfile wire format, pinned by two real containers	2026-09-02 16:02:46 +02:00
LICENSE	Initial commit: the gpfile wire format, pinned by two real containers	2026-09-02 16:02:46 +02:00
lint-rules.h	Initial commit: the gpfile wire format, pinned by two real containers	2026-09-02 16:02:46 +02:00
project.cpp	An agent, so a finger can mean something in your session	2026-09-05 06:21:53 +02:00
README.md	standby unlock: a locked session unlocks by finger without PAM	2026-09-23 17:53:11 +02:00

README.md

fingerprintd

Fingerprint daemon for the Fairphone 6 (milos, SM7635) on mainline Linux.

fingerprintd-core is a static library with no GLib, no libqcomtee and no system headers. Everything in it is a wire format or a state machine that was recovered by reverse-engineering, so all of it is pinned by tests that run on a dev box with no phone, no TEE and no sensor. The daemon shell holds everything that touches hardware.

Build

crafter-build              # bin/fingerprintd-<target>-<march>/fingerprintd
crafter-build test         # the unit suites

Cross-compiling for the phone:

packaging/make-sysroot.sh
crafter-build -- --target=aarch64-alpine-linux-musl --sysroot=~/.cache/fingerprintd/sysroot-aarch64-alpine --march=armv8.6-a+fp16fml+aes+sha3+sm4 --mtune=cortex-a720
crafter-build test --target=aarch64-alpine-linux-musl --sysroot=~/.cache/fingerprintd/sysroot-aarch64-alpine --march=armv8.6-a+fp16fml+aes+sha3+sm4 --mtune=cortex-a720

Verified on the device: all five suites pass cross-built and run on the phone itself, not only under emulation.

fprintd-enroll -f right-index-finger user   ten stages, enroll-completed
fprintd-list user                            - #0: right-index-finger
fprintd-verify user   (wrong finger)         verify-no-match, on the first press
fprintd-verify user   (enrolled finger)      verify-match,    on the first press

Lock-screen unlock

Two routes, both on by default:

PAM. The daemon provides fprintd, so a lock screen that runs pam_fprintd beside its password prompt unlocks by finger the usual way. Plasma's does (kde-fingerprint; the fingerprint-auth and postlogin services it needs are shipped here). Phosh's cannot: its PAM conversation answers every prompt with the password, so a fingerprint module in its stack would only stall the password behind the fingerprint timeout.
Standby. While the session in front on its seat is locked and the display is on, the daemon runs a verify of its own and answers a match with logind's Session.Unlock, which Phosh honours. No verify runs while the display is off (an open verify polls the sensor at ~5 Hz; the display state comes from the backlight's bl_power or the panel's DRM dpms, and a device with neither is treated as always on). Any fprintd client takes precedence: a Claim cancels the standby verify, a Release re-arms it. Only fingers named in that session owner's map unlock, and the map is re-read at every arm, so a finger deleted while locked stops counting at once. Per-finger no-unlock rules apply here too, and every match is announced as FingerMatched for the session agent. --standby-unlock=off disables it.

Runtime dependencies

The focal64 trustlet is proprietary and is not in this repo. It is extracted from the device's own stock Android partition on first boot by the fp6-vendor-blobs mechanism, the same way other firmware in fp6-img is.

License