Backend/Bitcoin: add recipient address checksum validation

Author: knocte

src/GWallet.Backend/Account.fs

@@ -96,18 +96,14 @@ module Account =
                         () // TODO: do something in this case??
         }
 
+    // TODO: add tests for these (just in case address validation breaks after upgrading our dependencies)
     let ValidateAddress (currency: Currency) (address: string) =
         match currency with
         | Currency.ETH | Currency.ETC ->
             Ether.Account.ValidateAddress currency address
-
         | Currency.BTC ->
             Bitcoin.Account.ValidateAddress address
 
-            // FIXME: add bitcoin checksum algorithm?
-        ()
-
-
     let EstimateFee account amount destination: IBlockchainFeeInfo =
         let currency = (account:>IAccount).Currency
         match currency with

src/GWallet.Backend/Bitcoin/BitcoinAccount.fs

@@ -401,4 +401,9 @@ module internal Account =
         if (address.Length < BITCOIN_MIN_ADDRESSES_LENGTH) then
             raise (AddressWithInvalidLength(BITCOIN_MIN_ADDRESSES_LENGTH))
 
-        // FIXME: add bitcoin checksum algorithm?
+        try
+            BitcoinAddress.Create(address, Config.BitcoinNet) |> ignore
+        with
+        // TODO: propose to NBitcoin upstream to generate an NBitcoin exception instead
+        | :? FormatException ->
+            raise (AddressWithInvalidChecksum None)

src/GWallet.Backend/Ether/EtherAccount.fs

@@ -54,7 +54,7 @@ module internal Account =
 
         if (not (addressUtil.IsChecksumAddress(address))) then
             let validCheckSumAddress = addressUtil.ConvertToChecksumAddress(address)
-            raise (AddressWithInvalidChecksum(validCheckSumAddress))
+            raise (AddressWithInvalidChecksum(Some validCheckSumAddress))
 
     let EstimateFee (currency: Currency): MinerFee =
         let gasPrice = Ether.Server.GetGasPrice currency

src/GWallet.Backend/Exceptions.fs

@@ -5,5 +5,5 @@ exception InvalidPassword
 exception DestinationEqualToOrigin
 exception AddressMissingProperPrefix of seq<string>
 exception AddressWithInvalidLength of int
-exception AddressWithInvalidChecksum of string
+exception AddressWithInvalidChecksum of Option<string>
 exception AccountAlreadyAdded

src/GWallet.Frontend.Console/UserInteraction.fs

@@ -321,15 +321,19 @@ module UserInteraction =
                     failwith (sprintf "Address introduced '%s' gave a length error with a limit that matches its length: %d=%d"
                                  publicAddress lengthLimitViolated publicAddress.Length)
                 AskPublicAddress currency askText
-            | AddressWithInvalidChecksum(addressWithValidChecksum) ->
+            | AddressWithInvalidChecksum maybeAddressWithValidChecksum ->
                 Console.Error.WriteLine "WARNING: the address provided didn't pass the checksum, are you sure you copied it properly?"
-                Console.Error.WriteLine "(If you used the clipboard, you're likely copying it from a service that doesn't have checksum validation.)"
                 Console.Error.WriteLine "(If you copied it by hand or somebody dictated it to you, you probably made a spelling mistake.)"
-                let continueWithoutChecksum = AskYesNo "Continue with this address?"
-                if (continueWithoutChecksum) then
-                    addressWithValidChecksum
-                else
+                match maybeAddressWithValidChecksum with
+                | None ->
                     AskPublicAddress currency askText
+                | Some addressWithValidChecksum ->
+                    Console.Error.WriteLine "(If you used the clipboard, you're likely copying it from a service that doesn't have checksum validation.)"
+                    let continueWithoutChecksum = AskYesNo "Continue with this address?"
+                    if (continueWithoutChecksum) then
+                        addressWithValidChecksum
+                    else
+                        AskPublicAddress currency askText
         validatedAddress
 
     type private AmountOption =