Adds Yubikey OTP Support

[Step7750]

Resolves #86
Feature Requests: #246

Features:

• Yubikey OTP Support
• Multiple keys (up to 5)
• Custom OTP Validation server

Known Issues:

• Panic when Caller Exits Early when Verifying OTP Against Multiple Servers wisespace-io/yubico-rs#4 The Yubico-rs library has an issue when sending out the OTP request to multiple validation servers simultaneously; any requests that finish after the caller has exited will panic.
  • Impact: Validation still works as intended but the console will be populated with a couple panics every time a key is validated or registered.

Requires pkg-config and libusb

[dani-garcia]

Nice work, I left a couple of comments that I'd like you to review.

About the libusb issue, the changes to the library were pretty simple so I made a fork for now: https://github.com/dani-garcia/yubico-rs.

I simply hid everything that required libusb under a feature flag, so you´ll need to change the Cargo.toml file:

yubico = { version = "0.4.0", default-features = false } 

...

[patch.crates-io]
yubico = { git = 'https://github.com/dani-garcia/yubico-rs' }

Hopefully if I get some time, I can make a proper PR upstream

[dani-garcia]

One last thing, how are the keys deleted? Does it use the endpoint receiving EnableYubikeyData and simply sets the keys to None? Or is there a separate endpoint that isn't implemented?

[Step7750]

You can use the /two-factor/disable endpoint that gets called when you click "Disable All Keys" or you can remove all Yubikeys in the form and save.

[dani-garcia]

Right, then I think this is ready to be merged.

Thanks for all your work, @Step7750!