[Infra] Enable passing signatures to SC method calls

src/Stratis.Bitcoin.Features.SmartContracts.Tests/SmartContractTransactionServiceTests.cs

@@ -1,10 +1,12 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
 using CSharpFunctionalExtensions;
 using Microsoft.Extensions.Logging;
 using Moq;
 using NBitcoin;
+using NBitcoin.DataEncoders;
 using Stratis.Bitcoin.Configuration.Logging;
 using Stratis.Bitcoin.Features.SmartContracts.Models;
 using Stratis.Bitcoin.Features.SmartContracts.Wallet;
@@ -974,5 +976,107 @@ public void BuildFeeEstimationContext_Recipient_Is_Not_P2PKH()
             )));
         }
         */
+
+        [Fact]
+        public void CanPassSignatures()
+        {
+            const int utxoIndex = 0;
+            uint256 utxoId = uint256.Zero;
+            uint256 utxoIdUnused = uint256.One;
+            string senderAddress = uint160.Zero.ToBase58Address(this.network);
+            string contractAddress = uint160.One.ToBase58Address(this.network);
+
+            var key1 = new Key();
+            var key2 = new Key();
+            var msg = "This is a test challenge";
+            var sig1 = key1.SignMessage(msg);
+            var sig2 = key2.SignMessage(msg);
+
+            var request = new BuildCallContractTransactionRequest
+            {
+                Amount = "0",
+                AccountName = "account 0",
+                ContractAddress = contractAddress,
+                FeeAmount = "0.01",
+                GasLimit = 100_000,
+                GasPrice = 100,
+                MethodName = "TestMethod",
+                WalletName = "wallet",
+                Password = "password",
+                Sender = senderAddress,
+                Outpoints = new List<OutpointRequest>
+                {
+                    new OutpointRequest
+                    {
+                        Index = utxoIndex,
+                        TransactionId = utxoId.ToString()
+                    },
+                },
+                Parameters = new[] { "SIG#" },
+                Signatures = new[] { sig1, sig2 }
+            };
+
+            this.walletManager.Setup(x => x.GetAddressBalance(request.Sender))
+                .Returns(new AddressBalance
+                {
+                    Address = senderAddress,
+                    AmountConfirmed = new Money(100, MoneyUnit.BTC)
+                });
+
+            this.walletManager.Setup(x => x.GetSpendableTransactionsInWallet(It.IsAny<string>(), 0))
+                .Returns(new List<UnspentOutputReference>
+                {
+                    new UnspentOutputReference
+                    {
+                        Address = new HdAddress
+                        {
+                            Address = senderAddress
+                        },
+                        Transaction = new TransactionData
+                        {
+                            Id = utxoId,
+                            Index = utxoIndex,
+                        }
+                    }, new UnspentOutputReference
+                    {
+                        Address = new HdAddress
+                        {
+                            Address = senderAddress
+                        },
+                        Transaction = new TransactionData
+                        {
+                            Id = utxoIdUnused,
+                            Index = utxoIndex,
+                        }
+                    }
+                });
+
+            var wallet = new Features.Wallet.Wallet();
+            wallet.AccountsRoot.Add(new AccountRoot(wallet));
+            var account0 = new HdAccount(wallet.AccountsRoot.First().Accounts) { Name = request.AccountName };
+            account0.ExternalAddresses.Add(new HdAddress() { Address = senderAddress });
+
+            this.walletManager.Setup(x => x.GetWallet(request.WalletName))
+                .Returns(wallet);
+
+            var reserveUtxoService = new ReserveUtxoService(this.loggerFactory, new Mock<ISignals>().Object);
+
+            var service = new SmartContractTransactionService(
+                this.network,
+                this.walletManager.Object,
+                this.walletTransactionHandler.Object,
+                this.stringSerializer.Object,
+                this.callDataSerializer.Object,
+                this.addressGenerator.Object,
+                this.stateRepository.Object,
+                reserveUtxoService);
+
+            BuildCallContractTransactionResponse result = service.BuildCallTx(request);
+
+            byte[] buffer = Convert.FromBase64String(sig1).Concat(Convert.FromBase64String(sig2)).ToArray();
+            string expected = $"{(int)MethodParameterDataType.ByteArray}#{Encoders.Hex.EncodeData(buffer)}";
+
+            this.stringSerializer.Verify(x => x.Deserialize(It.Is<string[]>(x => x[0] == expected)));
+        }
     }
 }

src/Stratis.Bitcoin.Features.SmartContracts/Models/BuildCallContractTransactionRequest.cs

@@ -104,6 +104,14 @@ public BuildCallContractTransactionRequest()
         /// </summary>
         public string[] Parameters { get; set; }
 
+        /// <summary>
+        /// An array of base 64 encoded strings containing the signatures to add.
+        /// </summary>
+        /// <remarks>
+        /// The strings passed here are typically obtained by signatories via the "signmessage" API by signing the "challenge" string returned by a method.
+        /// </remarks>
+        public string[] Signatures { get; set; }
+
         public override string ToString()
         {
             var builder = new StringBuilder();

src/Stratis.Bitcoin.Features.SmartContracts/Models/BuildCreateContractTransactionRequest.cs

@@ -96,6 +96,15 @@ public BuildCreateContractTransactionRequest()
         /// </summary>
         public string[] Parameters { get; set; }
 
+        /// <summary>
+        /// An array of base 64 encoded strings containing the signatures to add.
+        /// </summary>
+        /// <remarks>
+        /// The strings passed here are typically obtained by signatories via the "signmessage" API by signing the "challenge" string returned by a method.
+        /// </remarks>
+
+        public string[] Signatures { get; set; }
+
         public override string ToString()
         {
             var builder = new StringBuilder();

src/Stratis.Bitcoin.Features.SmartContracts/Wallet/SmartContractTransactionService.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using CSharpFunctionalExtensions;
 using NBitcoin;
+using NBitcoin.DataEncoders;
 using Stratis.Bitcoin.Features.SmartContracts.Models;
 using Stratis.Bitcoin.Features.Wallet;
 using Stratis.Bitcoin.Features.Wallet.Interfaces;
@@ -198,6 +199,41 @@ public BuildContractTransactionResult BuildTx(BuildContractTransactionRequest re
             return BuildContractTransactionResult.Success(model);
         }
 
+        private string[] ReplaceSignatures(string[] parameters, string[] signatures)
+        {
+            const int signatureLength = 65;
+            const int minHeaderByte = 27;
+            const int maxHeaderByte = 34;
+
+            if (parameters == null)
+                return null;
+
+            // Replace SIG# with any included signatures.
+            string encodedSigs = null;
+            for (int i = 0; i < parameters.Length; i++)
+            {
+                if (parameters[i].ToUpper() == "SIG#")
+                {
+                    if (encodedSigs == null)
+                    {
+                        var sigs = (signatures ?? new string[0]).Select(s => Convert.FromBase64String(s)).ToArray();
+                        if (sigs.Any(s => s.Length != signatureLength || s[0] < minHeaderByte || s[0] > maxHeaderByte))
+                            throw new Exception("Invalid signature(s).");
+
+                        var sigbuf = new byte[sigs.Length * signatureLength];
+                        for (int j = 0; j < sigs.Length; j++)
+                            Array.Copy(sigs[j], 0, sigbuf, j * signatureLength, signatureLength);
+
+                        encodedSigs = $"{(int)MethodParameterDataType.ByteArray}#{Encoders.Hex.EncodeData(sigbuf)}";
+                    }
+
+                    parameters[i] = encodedSigs;
+                }
+            }
+
+            return parameters;
+        }
+
         public BuildCallContractTransactionResponse BuildCallTx(BuildCallContractTransactionRequest request)
         {
             if (!this.CheckBalance(request.Sender))
@@ -214,6 +250,9 @@ public BuildCallContractTransactionResponse BuildCallTx(BuildCallContractTransac
             {
                 try
                 {
+                    // If signatures have been included then they replace the SIG# parameter.
+                    request.Parameters = ReplaceSignatures(request.Parameters, request.Signatures);
+
                     object[] methodParameters = this.methodParameterStringSerializer.Deserialize(request.Parameters);
                     txData = new ContractTxData(ReflectionVirtualMachine.VmVersion, (Stratis.SmartContracts.RuntimeObserver.Gas)request.GasPrice, (Stratis.SmartContracts.RuntimeObserver.Gas)request.GasLimit, addressNumeric, request.MethodName, methodParameters);
                 }
@@ -275,6 +314,9 @@ public BuildCreateContractTransactionResponse BuildCreateTx(BuildCreateContractT
             {
                 try
                 {
+                    // If signatures have been included then they replace the SIG# parameter.
+                    request.Parameters = ReplaceSignatures(request.Parameters, request.Signatures);
+
                     object[] methodParameters = this.methodParameterStringSerializer.Deserialize(request.Parameters);
                     txData = new ContractTxData(ReflectionVirtualMachine.VmVersion, (Stratis.SmartContracts.RuntimeObserver.Gas)request.GasPrice, (Stratis.SmartContracts.RuntimeObserver.Gas)request.GasLimit, request.ContractCode.HexToByteArray(), methodParameters);
                 }

src/Stratis.Bitcoin.Features.SmartContracts/Wallet/SmartContractWalletController.cs

@@ -7,6 +7,7 @@
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
 using NBitcoin;
+using NBitcoin.DataEncoders;
 using Stratis.Bitcoin.Connection;
 using Stratis.Bitcoin.Features.SmartContracts.Models;
 using Stratis.Bitcoin.Features.Wallet;