FIDO_DEV_SET_PIN(3)

💖 fido_dev_set_pin(3) 💖

okay bestie, gather round, because this is the Library Functions Manual page for fido_dev_set_pin(3) and it's literally the FIDO2 device-management glow-up you've been waiting for. four functions, one page, zero boring vibes. let's go 🦋

✨ NAME ✨

fido_dev_set_pin, fido_dev_get_retry_count, fido_dev_get_uv_retry_count, fido_dev_reset — FIDO2 device management functions

like… the whole squad. the PIN girlies, the retry-count girlies, and the reset icon. 👑

🌸 SYNOPSIS 🌸

#include <fido.h>

int
fido_dev_set_pin(fido_dev_t *dev, const char *pin, const char *oldpin);

int
fido_dev_get_retry_count(fido_dev_t *dev, int *retries);

int
fido_dev_get_uv_retry_count(fido_dev_t *dev, int *retries);

int
fido_dev_reset(fido_dev_t *dev);

💅 DESCRIPTION 💅

fido_dev_set_pin() 🎀

this one sets the PIN of device dev to pin, and pin is a NUL-terminated UTF-8 string — no cap, UTF-8 only, bestie. if oldpin is not NULL, then the device's PIN gets changed from oldpin to pin, where both pin and oldpin are NUL-terminated UTF-8 strings. it's giving "changing your password but make it a hardware key". 🔐

fido_dev_get_retry_count() 🔢

this fills retries with the number of PIN retries left in dev before lock-out, where retries is an addressable pointer. yes, addressable — hand it a real pointer, not a vibe. ✨

fido_dev_get_uv_retry_count() 👁️

same energy, different counter: this fills retries with the number of built-in UV retries left in dev before built-in UV is disabled, where retries is an addressable pointer. built-in UV said "i have a limit and i'm not afraid to use it". 💀

fido_dev_reset() 🌈

this performs a reset on dev, which resets the device's PIN and erases credentials stored on the device. big red button energy. it's iconic but it does not play. 🚨

not me reminding you again: fido_dev_set_pin(), fido_dev_get_retry_count(), fido_dev_get_uv_retry_count(), and fido_dev_reset() are synchronous and will block if necessary. they will simply wait. patiently. main character patience. 🫶

⭐ RETURN VALUES ⭐

the error codes returned by fido_dev_set_pin(), fido_dev_get_retry_count(), fido_dev_get_uv_retry_count(), and fido_dev_reset() are defined in <fido/err.h>. on success, FIDO_OK is returned. that's the slay outcome. ✅

🦋 SEE ALSO 🦋

• fido_cbor_info_uv_attempts(3)

iykyk. go read that one next, bestie. 📚

🍓 CAVEATS 🍓

okay this is the important part, so listen up fr fr.

regarding fido_dev_reset(): the actual user-flow to perform a reset is outside the scope of the FIDO2 specification, and may therefore vary depending on the authenticator. so like… every key does its own little dance. no universal choreography. 🙈

Yubico authenticators specifically will return FIDO_ERR_NOT_ALLOWED if a reset is issued later than 5 seconds after power-up, and FIDO_ERR_ACTION_TIMEOUT if the user fails to confirm the reset by touching the key within 30 seconds. so you've got 5 seconds to ask nicely and 30 seconds to actually touch the thing. no pressure, but also… pressure. ⏱️💀

and that's the whole page, bestie!! written by the Debian crew, dated May 25, 2018, and shipped in the Library Functions Manual — love that for them. mwah. 💜✨