Cancel authenticator operations for authenticators/interfaces that are not selected

[iinuwa]

Now that we're automatically starting discovery on all authenticators/interfaces, once a user selects a particular interface (e.g. when receiving a valid BLE advert, response to a wink command, etc.), we need to cancel authenticator operations on all the other non-selected authenticators/interfaces.

[iinuwa]

I looked into this a little bit and added a cancellation token to the USB service, and I see HID_CANCEL in the libwebauthn logs, but the authenticator stays active (glows blue) for about 15 more seconds after that.

2026-06-27T20:36:06.659829Z DEBUG credentialsd::dbus::flow_control: Cancelling request request_id=2424843831
2026-06-27T20:36:06.659919Z DEBUG credentialsd::credential_service: Cancelling request 2424843831
2026-06-27T20:36:06.723296Z TRACE libwebauthn::transport::hid::channel: hidapi read_timeout returned 0 bytes, continuing
2026-06-27T20:36:06.823639Z TRACE libwebauthn::transport::hid::channel: hidapi read_timeout returned 0 bytes, continuing
2026-06-27T20:36:06.848155Z TRACE credentialsd::dbus::ui_control: Object path disappeared from backend object_path=/org/freedesktop/portal/desktop/request/CREDENTIALSD_1169306350
2026-06-27T20:36:06.848565Z  INFO credentialsd::dbus::flow_control: Received signal to cancel request.
2026-06-27T20:36:06.848745Z TRACE credentialsd::credential_service::usb: Cancelled USB process
2026-06-27T20:36:06.849024Z TRACE credentialsd::credential_service::usb: Cancel blink
2026-06-27T20:36:06.874414Z DEBUG libwebauthn::transport::hid::channel: Received HID report len=64
2026-06-27T20:36:06.874577Z TRACE libwebauthn::transport::hid::channel: report=[0, 0, 0, 4, 187, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
2026-06-27T20:36:06.881242Z DEBUG libwebauthn::transport::hid::channel: Received U2F HID response cmd=KeepAlive payload_len=1
2026-06-27T20:36:06.881436Z TRACE libwebauthn::transport::hid::channel: response=HidMessage { cid: 4, cmd: KeepAlive, payload: [1] }
2026-06-27T20:36:06.883740Z DEBUG drop{dev=SoloKeys Solo 2 Security Key (r964)}:hid_cancel:hid_send{cmd=Cancel payload_len=0}: libwebauthn::transport::hid::channel: Sending packet as HID report packet=0 len=65
2026-06-27T20:36:06.883985Z TRACE drop{dev=SoloKeys Solo 2 Security Key (r964)}:hid_cancel:hid_send{cmd=Cancel payload_len=0}: libwebauthn::transport::hid::channel: report=[0, 0, 0, 0, 4, 145, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
2026-06-27T20:36:06.888778Z  WARN drop{dev=SoloKeys Solo 2 Security Key (r964)}: libwebauthn::transport::hid::channel: Failed to send hid_cancel on the channel being dropped err=Platform(Cancelled)

Similarly, on Drop, the hybrid device stops processing BLE advertisements, but it doesn't stop the BLE scan/subscription. At this time, I don't think there is any harm (I haven't noticed it causing issues with restarting another hybrid request in close succession), except for battery usage and the fact that it shows in the logs, making it harder to see other things.

I'm going to do some more testing on this, but @AlfioEmanueleFresta or @msirringhaus, if anything pops out to you immediately, let me know.

[iinuwa]

Never mind about the USB thing, my YubiKey works properly on HID cancel. I'll work on merging that and look more into the BLE scannign

[AlfioEmanueleFresta]

I'm working to improve cancellation on libwebauthn. As a note, this isn't uniform across transports.

• For HID we'd send CTAPHID_CANCEL (any op then errors with CTAP2_ERR_KEEPALIVE_CANCEL)
• For Hybrid, either tearing down the channel, or yielding control of the channel back to libwebauthn (lingering behaviour in fix(cable): send shutdown and linger for linking data libwebauthn#276)
• The internal authenticator means dismissing the local UV prompt and not much more.