pam_fprintd(8)

💅 pam_fprintd(8) — fingerprint auth, but make it PAM 💅

okay so bestie, you found pam_fprintd(8) — the manual page for the PAM module that talks to fprintd, the fingerprint daemon. lowkey iconic. no cap. 🫶

💖 NAME 💖

pam_fprintd — a PAM module that authenticates against fprintd, the fingerprint daemon. It checks a user’s fingerprints against fingerprints already enrolled through fprintd, the fingerprint management daemon. slay. 🫶

✨ SYNOPSIS ✨

pam_fprintd.so [debug|debug=[on|off|true|false|1|0]]
[max-tries=MAX_TRIES] [timeout=TIMEOUT]

🌸 DESCRIPTION 🌸

The pam_fprintd module verifies a user’s fingerprints against fingerprints enrolled using fprintd, the fingerprint management daemon. That’s the whole vibe: fingerprint check, PAM stack, go 💅.

🎀 OPTIONS 🎀

• debug, debug=[on|off|true|false|1|0] — turns debug on or off, bestie. The values are literally on, off, true, false, 1, and 0. Debug messages get generated using pam_syslog, which means by default they’ll be saved in the systemd journal. ✨
• max-tries=MAX_TRIES — how many fingerprint authentication attempts to try before returning an authentication failure. The minimum number of tries is 1, and the default is 3. Use a negative value to set no limit at all, so the module won’t ever error on multiple retries — but in that case it’s suggested for the module loader to handle this. 🫶
• timeout=TIMEOUT — how much time before returning an authentication failure. The default timeout is 30 seconds, with 1 second being the minimum. Use a negative value to set no limit at all, so fingerprint authentication will always be active while this module is loaded. ⏳

😭 LIMITATIONS 😭

The PAM stack is by design a serialised authentication, so it is not possible for pam_fprintd to allow authentication through passwords and fingerprints at the same time. not possible — not a skill issue, just the design. 💀

It is up to the application using the PAM services to implement separate PAM processes and run separate authentication stacks separately. This is the way multiple authentication methods are made available to users of gdm, for example. 🫶

👑 AUTHOR 👑

fprintd was written by Bastien Nocera. 👑

🌈 SEE ALSO 🌈

fprintd, PAM. go read those next, bestie. 🦋

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mwah 💋 this page’s source/version is freedesktop, dated 2025-04-10, and you’re reading pam_fprintd(8). periodt. 🦋