Merge pull request #748 from stackernews/524-autowithdraw-lnaddr-review

Small changes regarding automated withdrawals

api/resolvers/wallet.js

@@ -1,4 +1,4 @@
-import { createHodlInvoice, createInvoice, decodePaymentRequest, payViaPaymentRequest, cancelHodlInvoice, getInvoice as getInvoiceFromLnd, getNode } from 'ln-service'
+import { getIdentity, createHodlInvoice, createInvoice, decodePaymentRequest, payViaPaymentRequest, cancelHodlInvoice, getInvoice as getInvoiceFromLnd, getNode } from 'ln-service'
 import { GraphQLError } from 'graphql'
 import crypto from 'crypto'
 import serialize from './serial'
@@ -475,6 +475,19 @@ export async function sendToLnAddr (parent, { addr, amount, maxFee, comment, ...
   // decode invoice
   try {
     const decoded = await decodePaymentRequest({ lnd, request: res.pr })
+    const ourPubkey = (await getIdentity({ lnd })).public_key
+    if (autoWithdraw && decoded.destination === ourPubkey) {
+      // unset lnaddr so we don't trigger another withdrawal with same destination
+      await models.user.update({
+        where: { id: me.id },
+        data: {
+          lnAddr: null,
+          autoWithdrawThreshold: null,
+          autoWithdrawMaxFeePercent: null
+        }
+      })
+      throw new Error('automated withdrawals to other stackers are not allowed')
+    }
     if (decoded.description_hash !== lnurlPayDescriptionHash(`${options.metadata}${stringifiedPayerData}`)) {
       throw new Error('description hash does not match')
     }

lib/lnurl.js

@@ -28,7 +28,11 @@ export function lnurlPayDescriptionHash (data) {
 export async function lnAddrOptions (addr) {
   await lnAddrSchema().fields.addr.validate(addr)
   const [name, domain] = addr.split('@')
-  const protocol = domain.includes(':') && process.env.NODE_ENV === 'development' ? 'http' : 'https'
+  let protocol = 'https'
+  if (process.env.NODE_ENV === 'development') {
+    // support HTTP and HTTPS during development
+    protocol = process.env.PUBLIC_URL.split('://')[0]
+  }
   const req = await fetch(`${protocol}://${domain}/.well-known/lnurlp/${name}`)
   const res = await req.json()
   if (res.status === 'ERROR') {

lib/validate.js

@@ -208,10 +208,8 @@ export function lnAddrAutowithdrawSchema ({ me } = {}) {
   return object({
     lnAddr: lightningAddressValidator.required('required').test({
       name: 'lnAddr',
-      test: async addr => {
-        return addr !== `${me.name}@stacker.news` && !addr.startsWith(`${me.name}@localhost`)
-      },
-      message: 'cannot send to yourself'
+      test: addr => !addr.endsWith('@stacker.news'),
+      message: 'automated withdrawals must be external'
     }),
     autoWithdrawThreshold: intValidator.required('required').min(0, 'must be at least 0').max(msatsToSats(BALANCE_LIMIT_MSATS), `must be at most ${abbrNum(msatsToSats(BALANCE_LIMIT_MSATS))}`),
     autoWithdrawMaxFeePercent: floatValidator.required('required').min(0, 'must be at least 0').max(50, 'must not exceed 50')
@@ -444,3 +442,7 @@ export const lud18PayerDataSchema = (k1) => object({
   email: string().email('bad email address'),
   identifier: string()
 })
+
+// check if something is _really_ a number.
+// returns true for every number in this range: [-Infinity, ..., 0, ..., Infinity]
+export const isNumber = x => typeof x === 'number' && !Number.isNaN(x)

pages/settings/wallets/lightning-address.js

@@ -7,7 +7,7 @@ import { WalletButtonBar, WalletCard } from '../../../components/wallet-card'
 import { useMutation } from '@apollo/client'
 import { REMOVE_AUTOWITHDRAW, SET_AUTOWITHDRAW } from '../../../fragments/users'
 import { useToast } from '../../../components/toast'
-import { lnAddrAutowithdrawSchema } from '../../../lib/validate'
+import { lnAddrAutowithdrawSchema, isNumber } from '../../../lib/validate'
 import { useRouter } from 'next/router'
 import { useEffect, useState } from 'react'
 
@@ -15,7 +15,7 @@ export const getServerSideProps = getGetServerSideProps({ authRequired: true })
 
 function useAutoWithdrawEnabled () {
   const me = useMe()
-  return me?.privates?.lnAddr && !isNaN(me?.privates?.autoWithdrawThreshold) && !isNaN(me?.privates?.autoWithdrawMaxFeePercent)
+  return me?.privates?.lnAddr && isNumber(me?.privates?.autoWithdrawThreshold) && isNumber(me?.privates?.autoWithdrawMaxFeePercent)
 }
 
 export default function LightningAddress () {
@@ -25,7 +25,7 @@ export default function LightningAddress () {
   const [setAutoWithdraw] = useMutation(SET_AUTOWITHDRAW)
   const enabled = useAutoWithdrawEnabled()
   const [removeAutoWithdraw] = useMutation(REMOVE_AUTOWITHDRAW)
-  const autoWithdrawThreshold = isNaN(me?.privates?.autoWithdrawThreshold) ? 10000 : me?.privates?.autoWithdrawThreshold
+  const autoWithdrawThreshold = isNumber(me?.privates?.autoWithdrawThreshold) ? me?.privates?.autoWithdrawThreshold : 10000
   const [sendThreshold, setSendThreshold] = useState(Math.max(Math.floor(autoWithdrawThreshold / 10), 1))
 
   useEffect(() => {
@@ -39,8 +39,8 @@ export default function LightningAddress () {
       <Form
         initial={{
           lnAddr: me?.privates?.lnAddr || '',
-          autoWithdrawThreshold: isNaN(me?.privates?.autoWithdrawThreshold) ? 10000 : me?.privates?.autoWithdrawThreshold,
-          autoWithdrawMaxFeePercent: isNaN(me?.privates?.autoWithdrawMaxFeePercent) ? 1 : me?.privates?.autoWithdrawMaxFeePercent
+          autoWithdrawThreshold,
+          autoWithdrawMaxFeePercent: isNumber(me?.privates?.autoWithdrawMaxFeePercent) ? me?.privates?.autoWithdrawMaxFeePercent : 1
         }}
         schema={lnAddrAutowithdrawSchema({ me })}
         onSubmit={async ({ autoWithdrawThreshold, autoWithdrawMaxFeePercent, ...values }) => {
@@ -73,7 +73,7 @@ export default function LightningAddress () {
             const value = e.target.value
             setSendThreshold(Math.max(Math.floor(value / 10), 1))
           }}
-          hint={isNaN(sendThreshold) ? undefined : `note: will attempt withdrawal when desired balance is exceeded by ${sendThreshold} sats`}
+          hint={isNumber(sendThreshold) ? `note: will attempt withdraw when threshold is exceeded by ${sendThreshold} sats` : undefined}
           append={<InputGroup.Text className='text-monospace'>sats</InputGroup.Text>}
         />
         <Input

worker/wallet.js

@@ -9,6 +9,7 @@ import { INVOICE_RETENTION_DAYS } from '../lib/constants'
 import { sleep } from '../lib/time.js'
 import { sendToLnAddr } from '../api/resolvers/wallet.js'
 import retry from 'async-retry'
+import { isNumber } from '../lib/validate.js'
 
 export async function subscribeToWallet (args) {
   await subscribeToDeposits(args)
@@ -292,8 +293,8 @@ export async function autoWithdraw ({ data: { id }, models, lnd }) {
   const user = await models.user.findUnique({ where: { id } })
   if (!user ||
     !user.lnAddr ||
-    isNaN(user.autoWithdrawThreshold) ||
-    isNaN(user.autoWithdrawMaxFeePercent)) return
+    !isNumber(user.autoWithdrawThreshold) ||
+    !isNumber(user.autoWithdrawMaxFeePercent)) return
 
   const threshold = satsToMsats(user.autoWithdrawThreshold)
   const excess = Number(user.msats - threshold)