U2F exchange hangs after more than 30 seconds about ledgerjs HOT 2 CLOSED

This sounds like an issue I solved for my Nano (the currency) app. The underlying problem here is that the Chrome U2F extension has a hard-coded timeout of 31 seconds (if memory serves). When it hasn't received an answer from the dongle during that time it will kill the request.

There is a way to allow for longer requests, but it requires support from the app running on the Ledger device. The trick is to return the BUSY U2F status code before the 31 second hard-timeout. That will force the U2F extension to retry the request. But this also means that the Ledger app needs to be able to map the 2nd incoming request to the 1st one that's still ongoing (or that recently finished).

I guess the best way would be to just document this in setExchangeTimeout and warn ledger.js users that most apps out there don't handle timeouts of more than 30 seconds well.

Here are the relevant Nano [currency] app code snippets that allow for longer requests:

• Returning the BUSY status code - roosmaa/blue-app-nano/src/main.c#L40-L53
• Triggering a timeout before the 31 second force-kill - roosmaa/blue-app-nano/src/main.c#L125-L133
• Mapping the request back to the ongoing one - roosmaa/blue-app-nano/src/nano.c#L46-L65

from ledgerjs.

it will be more and more recommended to use WebUSB/WebHID over U2F.

from ledgerjs.