Add address network validation (#60)

* Add network address validation

* Add API error

* remove unnecessary error

* reset client

* remove double period

* add prefix

lib/constants.ts

@@ -24,8 +24,16 @@ export const CREATE_ACCOUNT_ERROR = "Account creation has failed"
 export const FUND_ACCOUNT_ERROR = "Account funding has failed"
 export const MISSING_FUSD_VAULT_ERROR =
   "This account does not have an FUSD vault"
+export const INVALID_NETWORK_ADDRESS_ERROR = (network: Networks) =>
+  `This address is invalid for ${network}, please verify that it is correct`
 
 export const paths = {
   root: "/",
   fundAccount: "/fund-account",
 }
+
+export const ADDRESS_REGEXP = /^(0x)?[0-9a-fA-F]{16}$/
+
+export const NETWORK_CODEWORDS = {
+  testnet: "0x6834ba37b3980209",
+}

lib/network.ts

@@ -1,4 +1,42 @@
 import capitalize from "./capitalize"
+import {ADDRESS_REGEXP, NETWORK_CODEWORDS} from "./constants"
 import publicConfig from "./publicConfig"
+import * as fcl from "@onflow/fcl"
 
 export const NETWORK_DISPLAY_NAME = capitalize(publicConfig.network)
+
+// Network address validation taken from flow-go
+// https://github.com/onflow/flow-go/blob/043570794069a876072d50de4dc03bbd34f063c7/model/flow/address.go
+
+const linearCodeN = 64
+const parityCheckMatrixColumns = [
+  0x00001, 0x00002, 0x00004, 0x00008, 0x00010, 0x00020, 0x00040, 0x00080,
+  0x00100, 0x00200, 0x00400, 0x00800, 0x01000, 0x02000, 0x04000, 0x08000,
+  0x10000, 0x20000, 0x40000, 0x7328d, 0x6689a, 0x6112f, 0x6084b, 0x433fd,
+  0x42aab, 0x41951, 0x233ce, 0x22a81, 0x21948, 0x1ef60, 0x1deca, 0x1c639,
+  0x1bdd8, 0x1a535, 0x194ac, 0x18c46, 0x1632b, 0x1529b, 0x14a43, 0x13184,
+  0x12942, 0x118c1, 0x0f812, 0x0e027, 0x0d00e, 0x0c83c, 0x0b01d, 0x0a831,
+  0x0982b, 0x07034, 0x0682a, 0x05819, 0x03807, 0x007d2, 0x00727, 0x0068e,
+  0x0067c, 0x0059d, 0x004eb, 0x003b4, 0x0036a, 0x002d9, 0x001c7, 0x0003f,
+]
+
+export function isValidNetworkAddress(
+  address: string,
+  network: keyof typeof NETWORK_CODEWORDS
+) {
+  address = fcl.withPrefix(address) || ""
+  if (ADDRESS_REGEXP.test(address) === false) return false
+
+  let codeword = BigInt(address) ^ BigInt(NETWORK_CODEWORDS[network])
+  let parity = 0
+
+  if (codeword === BigInt(0)) return false
+
+  for (let i = 0; i < linearCodeN; i++) {
+    if (codeword % BigInt(2) === BigInt(1)) {
+      parity ^= parityCheckMatrixColumns[i]
+    }
+    codeword >>= BigInt(1)
+  }
+  return parity === 0
+}

lib/validate.tsx

@@ -3,6 +3,7 @@ import {
   ACCOUNTS_KEYS_DOCS_URL,
   ADDRESS_FORMAT_ERROR,
   ADDRESS_MISSING_ERROR,
+  ADDRESS_REGEXP,
   GENERATE_KEYS_DOCS_URL,
   PUBLIC_KEY_FORMAT_ERROR,
   PUBLIC_KEY_MISSING_ERROR,
@@ -53,7 +54,7 @@ export const createAccountSchemaServer = yup
 const fundAccountSchemaClientShape = {
   address: yup
     .string()
-    .matches(/^(0x)?([0-9a-f]{16})$/i, () => (
+    .matches(ADDRESS_REGEXP, () => (
       <>
         {ADDRESS_FORMAT_ERROR}{" "}
         <Link href={ACCOUNTS_KEYS_DOCS_URL} target="_blank" variant="underline">

pages/api/fund.ts

@@ -1,7 +1,11 @@
 import * as fcl from "@onflow/fcl"
 import * as t from "@onflow/types"
 import {verify} from "hcaptcha"
-import {FUSD_TYPE, MISSING_FUSD_VAULT_ERROR} from "lib/constants"
+import {
+  FUSD_TYPE,
+  INVALID_NETWORK_ADDRESS_ERROR,
+  MISSING_FUSD_VAULT_ERROR,
+} from "lib/constants"
 import publicConfig from "lib/publicConfig"
 import {NextApiRequest, NextApiResponse} from "next"
 import config from "../../lib/config"
@@ -10,6 +14,7 @@ import {getSignerKeyIndex} from "../../lib/keys"
 import {fundAccountSchemaServer} from "../../lib/validate"
 import {verifyAPIKey} from "../../lib/common"
 import {ValidationError} from "yup"
+import {isValidNetworkAddress} from "lib/network"
 
 const scriptCheckFUSDVault = `
   import FUSD from ${publicConfig.contractFUSD}
@@ -44,6 +49,14 @@ export default async function fund(req: NextApiRequest, res: NextApiResponse) {
     const address = fcl.withPrefix(req.body.address) || ""
     const token = req.body.token
 
+    // Validate address
+    if (!isValidNetworkAddress(address, publicConfig.network)) {
+      res
+        .status(400)
+        .json({errors: [INVALID_NETWORK_ADDRESS_ERROR(publicConfig.network)]})
+      return
+    }
+
     if (token === FUSD_TYPE) {
       try {
         const hasFUSDVault = await fcl