feat: added escrow contract

e2e/interchaintestv8/e2esuite/utils.go

@@ -47,6 +47,7 @@ type DeployedContracts struct {
 	Ics26Router     string `json:"ics26Router"`
 	Ics20Transfer   string `json:"ics20Transfer"`
 	Erc20           string `json:"erc20"`
+	Escrow          string `json:"escrow"`
 }
 
 // FundAddressChainB sends funds to the given address on Chain B.
@@ -133,6 +134,8 @@ func (s *TestSuite) GetEthContractsFromDeployOutput(stdout string) DeployedContr
 	s.Require().True(IsLowercase(embeddedContracts.Ics20Transfer))
 	s.Require().NotEmpty(embeddedContracts.Ics26Router)
 	s.Require().True(IsLowercase(embeddedContracts.Ics26Router))
+	s.Require().NotEmpty(embeddedContracts.Escrow)
+	s.Require().True(IsLowercase(embeddedContracts.Escrow))
 
 	return embeddedContracts
 }

e2e/interchaintestv8/ibc_eureka_test.go

@@ -65,11 +65,12 @@ type IbcEurekaTestSuite struct {
 
 	contractAddresses e2esuite.DeployedContracts
 
-	sp1Ics07Contract *sp1ics07tendermint.Contract
-	ics02Contract    *ics02client.Contract
-	ics26Contract    *ics26router.Contract
-	ics20Contract    *ics20transfer.Contract
-	erc20Contract    *erc20.Contract
+	sp1Ics07Contract   *sp1ics07tendermint.Contract
+	ics02Contract      *ics02client.Contract
+	ics26Contract      *ics26router.Contract
+	ics20Contract      *ics20transfer.Contract
+	erc20Contract      *erc20.Contract
+	escrowContractAddr ethcommon.Address
 
 	simdClientID string
 	ethClientID  string
@@ -192,6 +193,7 @@ func (s *IbcEurekaTestSuite) SetupSuite(ctx context.Context) {
 		s.Require().NoError(err)
 		s.erc20Contract, err = erc20.NewContract(ethcommon.HexToAddress(s.contractAddresses.Erc20), ethClient)
 		s.Require().NoError(err)
+		s.escrowContractAddr = ethcommon.HexToAddress(s.contractAddresses.Escrow)
 	}))
 
 	s.T().Cleanup(func() {
@@ -407,9 +409,9 @@ func (s *IbcEurekaTestSuite) TestICS20TransferERC20TokenfromEthereumToCosmosAndB
 			s.Require().Equal(testvalues.InitialBalance-testvalues.TransferAmount, userBalance.Int64())
 
 			// ICS20 contract balance on Ethereum
-			ics20TransferBalance, err := s.erc20Contract.BalanceOf(nil, ics20Address)
+			escrowBalance, err := s.erc20Contract.BalanceOf(nil, s.escrowContractAddr)
 			s.Require().NoError(err)
-			s.Require().Equal(transferAmount, ics20TransferBalance)
+			s.Require().Equal(transferAmount, escrowBalance)
 		}))
 	}))
 
@@ -497,9 +499,9 @@ func (s *IbcEurekaTestSuite) TestICS20TransferERC20TokenfromEthereumToCosmosAndB
 			s.Require().Equal(testvalues.InitialBalance-testvalues.TransferAmount, userBalance.Int64())
 
 			// ICS20 contract balance on Ethereum
-			ics20Bal, err := s.erc20Contract.BalanceOf(nil, ics20Address)
+			escrowBalance, err := s.erc20Contract.BalanceOf(nil, s.escrowContractAddr)
 			s.Require().NoError(err)
-			s.Require().Equal(testvalues.TransferAmount, ics20Bal.Int64())
+			s.Require().Equal(testvalues.TransferAmount, escrowBalance.Int64())
 		}))
 	}))
 
@@ -619,9 +621,9 @@ func (s *IbcEurekaTestSuite) TestICS20TransferERC20TokenfromEthereumToCosmosAndB
 			s.Require().NoError(err)
 			s.Require().Equal(testvalues.InitialBalance, userBalance.Int64())
 
-			ics20TransferBalance, err := s.erc20Contract.BalanceOf(nil, ics20Address)
+			escrowBalance, err := s.erc20Contract.BalanceOf(nil, s.escrowContractAddr)
 			s.Require().NoError(err)
-			s.Require().Equal(int64(0), ics20TransferBalance.Int64())
+			s.Require().Equal(int64(0), escrowBalance.Int64())
 		}))
 	}))
 
@@ -1044,10 +1046,9 @@ func (s *IbcEurekaTestSuite) TestICS20TransferTimeoutFromEthereumToCosmosChain()
 			s.Require().Equal(testvalues.InitialBalance-testvalues.TransferAmount, userBalance.Int64())
 
 			// ICS20 contract balance on Ethereum
-			ics20Address := ethcommon.HexToAddress(s.contractAddresses.Ics20Transfer)
-			ics20Bal, err := s.erc20Contract.BalanceOf(nil, ics20Address)
+			escrowBalance, err := s.erc20Contract.BalanceOf(nil, s.escrowContractAddr)
 			s.Require().NoError(err)
-			s.Require().Equal(transferAmount, ics20Bal)
+			s.Require().Equal(transferAmount, escrowBalance)
 		}))
 	}))
 
@@ -1094,10 +1095,9 @@ func (s *IbcEurekaTestSuite) TestICS20TransferTimeoutFromEthereumToCosmosChain()
 			s.Require().Equal(testvalues.InitialBalance, userBalance.Int64())
 
 			// ICS20 contract balance on Ethereum
-			ics20Address := ethcommon.HexToAddress(s.contractAddresses.Ics20Transfer)
-			ics20Bal, err := s.erc20Contract.BalanceOf(nil, ics20Address)
+			escrowBalance, err := s.erc20Contract.BalanceOf(nil, s.escrowContractAddr)
 			s.Require().NoError(err)
-			s.Require().Equal(int64(0), ics20Bal.Int64())
+			s.Require().Equal(int64(0), escrowBalance.Int64())
 		}))
 	}))
 }

scripts/E2ETestDeploy.s.sol

@@ -78,6 +78,7 @@ contract E2ETestDeploy is Script {
         json.serialize("ics02Client", Strings.toHexString(address(ics02Client)));
         json.serialize("ics26Router", Strings.toHexString(address(ics26Router)));
         json.serialize("ics20Transfer", Strings.toHexString(address(ics20Transfer)));
+        json.serialize("escrow", Strings.toHexString(ics20Transfer.escrow()));
         string memory finalJson = json.serialize("erc20", Strings.toHexString(address(erc20)));
 
         return finalJson;

scripts/MockE2ETestDeploy.s.sol

@@ -68,6 +68,7 @@ contract MockE2ETestDeploy is Script {
         // Mint some tokens
         (address addr, bool ok) = ICS20Lib.hexStringToAddress(E2E_FAUCET);
         require(ok, "invalid address");
+
         erc20.mint(addr, 1_000_000_000_000_000_000);
 
         vm.stopBroadcast();
@@ -77,6 +78,7 @@ contract MockE2ETestDeploy is Script {
         json.serialize("ics02Client", Strings.toHexString(address(ics02Client)));
         json.serialize("ics26Router", Strings.toHexString(address(ics26Router)));
         json.serialize("ics20Transfer", Strings.toHexString(address(ics20Transfer)));
+        json.serialize("escrow", Strings.toHexString(ics20Transfer.escrow()));
         string memory finalJson = json.serialize("erc20", Strings.toHexString(address(erc20)));
 
         return finalJson;

src/ICS20Transfer.sol

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: MIT
 pragma solidity >=0.8.25;
 
+import { IEscrow } from "./interfaces/IEscrow.sol";
 import { IIBCApp } from "./interfaces/IIBCApp.sol";
 import { IICS20Errors } from "./errors/IICS20Errors.sol";
 import { ICS20Lib } from "./utils/ICS20Lib.sol";
@@ -13,6 +14,7 @@ import { IICS26Router } from "./interfaces/IICS26Router.sol";
 import { IICS26RouterMsgs } from "./msgs/IICS26RouterMsgs.sol";
 import { Strings } from "@openzeppelin/contracts/utils/Strings.sol";
 import { IBCERC20 } from "./utils/IBCERC20.sol";
+import { Escrow } from "./utils/Escrow.sol";
 
 using SafeERC20 for IERC20;
 
@@ -22,11 +24,20 @@ using SafeERC20 for IERC20;
  * - Related to escrow ^: invariant checking (where to implement that?)
  */
 contract ICS20Transfer is IIBCApp, IICS20Transfer, IICS20Errors, Ownable, ReentrancyGuard {
+    /// @notice The escrow contract address
+    IEscrow private immutable ESCROW;
     /// @notice Mapping of non-native denoms to their respective IBCERC20 contracts created here
-    mapping(string denom => IBCERC20 ibcERC20Contract) private _foreignDenomContracts;
+    mapping(string denom => IBCERC20 ibcERC20Contract) private _ibcDenomContracts;
 
     /// @param owner_ The owner of the contract
-    constructor(address owner_) Ownable(owner_) { }
+    constructor(address owner_) Ownable(owner_) {
+        ESCROW = new Escrow(address(this));
+    }
+
+    /// @inheritdoc IICS20Transfer
+    function escrow() external view override returns (address) {
+        return address(ESCROW);
+    }
 
     /// @inheritdoc IICS20Transfer
     function sendTransfer(SendTransferMsg calldata msg_) external override returns (uint32) {
@@ -84,7 +95,7 @@ contract ICS20Transfer is IIBCApp, IICS20Transfer, IICS20Errors, Ownable, Reentr
         (address erc20Address, bool originatorChainIsSource) = getSendERC20AddressAndSource(msg_.packet, packetData);
 
         // transfer the tokens to us (requires the allowance to be set)
-        _transferFrom(sender, address(this), erc20Address, packetData.amount);
+        _transferFrom(sender, address(ESCROW), erc20Address, packetData.amount);
 
         if (!originatorChainIsSource) {
             // receiver chain is source: burn the vouchers
@@ -124,7 +135,7 @@ contract ICS20Transfer is IIBCApp, IICS20Transfer, IICS20Errors, Ownable, Reentr
         }
 
         // transfer the tokens to the receiver
-        IERC20(erc20Address).safeTransfer(receiver, packetData.amount);
+        ESCROW.send(IERC20(erc20Address), receiver, packetData.amount);
 
         // Note the event don't take into account the conversion
         emit ICS20ReceiveTransfer(packetData, erc20Address);
@@ -159,7 +170,7 @@ contract ICS20Transfer is IIBCApp, IICS20Transfer, IICS20Errors, Ownable, Reentr
     /// @param erc20Address The address of the ERC20 contract
     function _refundTokens(ICS20Lib.PacketDataJSON memory packetData, address erc20Address) private {
         address refundee = ICS20Lib.mustHexStringToAddress(packetData.sender);
-        IERC20(erc20Address).safeTransfer(refundee, packetData.amount);
+        ESCROW.send(IERC20(erc20Address), refundee, packetData.amount);
     }
 
     /// @notice Transfer tokens from sender to receiver
@@ -209,7 +220,7 @@ contract ICS20Transfer is IIBCApp, IICS20Transfer, IICS20Errors, Ownable, Reentr
         } else {
             // receiving chain is source of the token, so we've received and mapped this token before
             string memory ibcDenom = ICS20Lib.toIBCDenom(packetData.denom);
-            erc20Address = address(_foreignDenomContracts[ibcDenom]);
+            erc20Address = address(_ibcDenomContracts[ibcDenom]);
             if (erc20Address == address(0)) {
                 revert ICS20DenomNotFound(packetData.denom);
             }
@@ -259,11 +270,11 @@ contract ICS20Transfer is IIBCApp, IICS20Transfer, IICS20Errors, Ownable, Reentr
     function findOrCreateERC20Address(string memory fullDenomPath, string memory base) internal returns (address) {
         // check if denom already has a foreign registered contract
         string memory ibcDenom = ICS20Lib.toIBCDenom(fullDenomPath);
-        address erc20Contract = address(_foreignDenomContracts[ibcDenom]);
+        address erc20Contract = address(_ibcDenomContracts[ibcDenom]);
         if (erc20Contract == address(0)) {
             // nothing exists, so we create new erc20 contract and register it in the mapping
-            IBCERC20 ibcERC20 = new IBCERC20(IICS20Transfer(address(this)), ibcDenom, base, fullDenomPath);
-            _foreignDenomContracts[ibcDenom] = ibcERC20;
+            IBCERC20 ibcERC20 = new IBCERC20(this, ESCROW, ibcDenom, base, fullDenomPath);
+            _ibcDenomContracts[ibcDenom] = ibcERC20;
             erc20Contract = address(ibcERC20);
         }
 

src/interfaces/IEscrow.sol

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.25;
+
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+/// @title Escrow Contract Interface
+/// @notice This interface is implemented by the Escrow contract
+interface IEscrow {
+    /// @notice Send tokens to the specified address
+    /// @param token The token to send
+    /// @param to The address to send the tokens to
+    /// @param amount The amount of tokens to send
+    function send(IERC20 token, address to, uint256 amount) external;
+}

src/interfaces/IIBCERC20.sol

@@ -4,11 +4,11 @@ pragma solidity >=0.8.25;
 import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 
 interface IIBCERC20 is IERC20 {
-    /// @notice Mint new tokens to the ICS20Transfer contract
+    /// @notice Mint new tokens to the Escrow contract
     /// @param amount Amount of tokens to mint
     function mint(uint256 amount) external;
 
-    /// @notice Burn tokens from the ICS20Transfer contract
+    /// @notice Burn tokens from the Escrow contract
     /// @param amount Amount of tokens to burn
     function burn(uint256 amount) external;
 

src/interfaces/IICS20Transfer.sol

@@ -28,4 +28,8 @@ interface IICS20Transfer is IICS20TransferMsgs {
     /// @param msg The message for sending a transfer
     /// @return sequence The sequence number of the packet created
     function sendTransfer(SendTransferMsg calldata msg) external returns (uint32 sequence);
+
+    /// @notice Retrieve the escrow contract address
+    /// @return The escrow contract address
+    function escrow() external view returns (address);
 }

src/utils/Escrow.sol

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.25;
+
+import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
+import { IEscrow } from "../interfaces/IEscrow.sol";
+
+using SafeERC20 for IERC20;
+
+/// @title Escrow Contract
+/// @notice This contract is used to escrow the funds for the ICS20 contract
+contract Escrow is Ownable, IEscrow {
+    /// @param owner_ The owner of the contract
+    /// @dev Owner is to be the ICS20Transfer contract
+    constructor(address owner_) Ownable(owner_) { }
+
+    /// @inheritdoc IEscrow
+    function send(IERC20 token, address to, uint256 amount) external override onlyOwner {
+        token.safeTransfer(to, amount);
+    }
+}

src/utils/IBCERC20.sol

@@ -5,13 +5,17 @@ import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import { IICS20Transfer } from "../interfaces/IICS20Transfer.sol";
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 import { IIBCERC20 } from "../interfaces/IIBCERC20.sol";
+import { IEscrow } from "../interfaces/IEscrow.sol";
 
 contract IBCERC20 is IIBCERC20, ERC20, Ownable {
     /// @notice The full IBC denom path for this token
     string private _fullDenomPath;
+    /// @notice The escrow contract address
+    IEscrow private immutable ESCROW;
 
     constructor(
         IICS20Transfer owner_,
+        IEscrow escrow_,
         string memory ibcDenom_,
         string memory baseDenom_,
         string memory fullDenomPath_
@@ -20,6 +24,7 @@ contract IBCERC20 is IIBCERC20, ERC20, Ownable {
         Ownable(address(owner_))
     {
         _fullDenomPath = fullDenomPath_;
+        ESCROW = escrow_;
     }
 
     /// @inheritdoc IIBCERC20
@@ -29,11 +34,11 @@ contract IBCERC20 is IIBCERC20, ERC20, Ownable {
 
     /// @inheritdoc IIBCERC20
     function mint(uint256 amount) external onlyOwner {
-        _mint(owner(), amount);
+        _mint(address(ESCROW), amount);
     }
 
     /// @inheritdoc IIBCERC20
     function burn(uint256 amount) external onlyOwner {
-        _burn(owner(), amount);
+        _burn(address(ESCROW), amount);
     }
 }