Eclair accepts payments after payment request timeout period.

[n1bor]

Describe the issue
I create a payment request and specify a timeout of 1 second.
I check the payment request and it correctly contains the 1 second timeout.
I wait 10 seconds.
I pay the payment request from another node.

What behaviour did you expect?
The payment should be rejected.
BOLT#11
A payee SHOULD NOT accept a payment after timestamp plus expiry.
https://github.com/lightningnetwork/lightning-rfc/blob/master/11-payment-encoding.md#payer--payee-requirements

What was the actual behaviour (provide screenshots if the issue is GUI-related)?
The payment is accepted.

How reliably can you reproduce the issue, what are the steps to do so?
100% - steps are above.

What version of Eclair are you using, where did you get it (website, self-compiled, etc)?
HEAD as of 26th Oct 2018

What environment are you observing the error on (OS, JDK version)?
Linux/1.8

Any extra information that might be useful in the debugging process.
This match in LocalPaymentHandler has no logic to check the timeout.
In addition to the check on paymentRequest.amount here:

eclair/eclair-core/src/main/scala/fr/acinq/eclair/payment/LocalPaymentHandler.scala

Line 78 in 2de7c6b

paymentRequest.amount match {

We need a check on paymentRequest.expirySeconds in here:

eclair/eclair-core/src/main/scala/fr/acinq/eclair/payment/LocalPaymentHandler.scala

Line 88 in 2de7c6b

log.info(s"received payment for paymentHash=${htlc.paymentHash} amountMsat=${htlc.amountMsat}")

[sstone]

Yes, this true but only for payment requests with a timeout that is less than 10 minutes which is still very uncommon (because we check and purge payment requests every 10 minutes).

[n1bor]

Issue is when you have some deadline for a payment - say a competition etc... then if you get a payment after the deadline you have to return the funds. Which with lighting is more trick than bitcoin as you have no return address by default.
Also currently there is no test for the expiry field. At least with this patch that is now covered!