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Add DestinationSettler2 and DestinationSettler3 variants
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| Original file line number | Diff line number | Diff line change |
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| pragma solidity ^0.8.0; | ||
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| import {ReentrancyGuard} from "@openzeppelin/contracts/utils/ReentrancyGuard.sol"; | ||
| import {SignatureChecker} from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol"; | ||
| import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol"; | ||
| import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol"; | ||
| import {GaslessCrossChainOrder} from "./ERC7683.sol"; | ||
| import {CallByUser, Call} from "./Structs.sol"; | ||
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| /** | ||
| * @notice Destination chain entrypoint contract for fillers relaying cross chain message containing delegated | ||
| * calldata. | ||
| * @dev The difference between this contract and the DestinationSettler.sol contract is that this contract | ||
| * performs all the CallByUser signature verification rather than having the XAccount contract do it. This reduces | ||
| * gas costs in the `fill()` function but it does mean that all users must trust the DestinationSettler | ||
| * contract since it performs the signature verification. Unlike this contract, the DestinationSettler.sol contract | ||
| * can be swapped out for another settlement contract because the XAccount provides the signature verification | ||
| * protection for the user. As a result, the XAccount smart contract wallet used by this settler is much more | ||
| * lightweight than the one used by the DestinationSettler.sol contract. | ||
| */ | ||
| contract DestinationSettler2 is ReentrancyGuard { | ||
| using SafeERC20 for IERC20; | ||
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| mapping(bytes32 => bool) public fillStatuses; | ||
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| // Called by filler, who sees ERC7683 intent emitted on origin chain | ||
| // containing the callsByUser data to be executed following a 7702 delegation. | ||
| // @dev We don't use the last parameter `fillerData` in this function. | ||
| function fill(bytes32 orderId, bytes calldata originData, bytes calldata) external nonReentrant { | ||
| (CallByUser memory callsByUser) = abi.decode(originData, (CallByUser)); | ||
| // Verify orderId? | ||
| // require(orderId == keccak256(originData), "Wrong order data"); | ||
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| // Protect against duplicate fills. | ||
| require(!fillStatuses[orderId], "Already filled"); | ||
| fillStatuses[orderId] = true; | ||
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| // TODO: Protect fillers from collisions with other fillers. Requires letting user set an exclusive relayer. | ||
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| // Pull funds into this settlement contract and perform any steps necessary to ensure that filler | ||
| // receives a refund of their assets. | ||
| _fundUser(callsByUser); | ||
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| _verifyCalls(callsByUser); | ||
| _verify7702Delegation(); | ||
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| // The following call will only succeed if the user has set a 7702 authorization to set its code | ||
| // equal to the XAccount contract. The filler should have seen any auth data emitted in an OriginSettler | ||
| // event on the sending chain. | ||
| XAccount(payable(callsByUser.user)).xExecute(callsByUser); | ||
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| // Perform any final steps required to prove that filler has successfully filled the ERC7683 intent. | ||
| // For example, we could emit an event containing a unique hash of the fill that could be proved | ||
| // on the origin chain via a receipt proof + RIP7755. | ||
| // e.g. emit Executed(orderId) | ||
| } | ||
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| // Pull funds into this settlement contract as escrow and use to execute user's calldata. Escrowed | ||
| // funds will be paid back to filler after this contract successfully verifies the settled intent. | ||
| // This step could be skipped by lightweight escrow systems that don't need to perform additional | ||
| // validation on the filler's actions. | ||
| function _fundUser(CallByUser memory call) internal { | ||
| IERC20(call.asset.token).safeTransferFrom(msg.sender, call.user, call.asset.amount); | ||
| } | ||
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| function _verifyCalls(CallByUser memory userCalls) internal view { | ||
| require(userCalls.chainId == block.chainid); | ||
| // TODO: Make the blob to sign EIP712-compatible (i.e. instead of keccak256(abi.encode(...)) set | ||
| // this to SigningLib.getTypedDataHash(...) | ||
| require( | ||
| SignatureChecker.isValidSignatureNow( | ||
| userCalls.user, keccak256(abi.encode(userCalls.calls, userCalls.nonce)), userCalls.signature | ||
| ) | ||
| ); | ||
| } | ||
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| function _verify7702Delegation() internal { | ||
| // TODO: We might not need this function at all, because if the authorization data requires that this contract | ||
| // is set as the delegation code, then xExecute would fail if the auth data is not submitted by the filler. | ||
| // However, it might still be useful to verify that the delegate is set correctly, like checking EXTCODEHASH. | ||
| } | ||
| } | ||
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| // TODO: Move to separate file once we are more confident in architecture. For now keep here for readability. | ||
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| /** | ||
| * @notice Singleton contract used by all users who want to sign data on origin chain and delegate execution of | ||
| * their calldata on this chain to this contract. | ||
| */ | ||
| contract XAccount is ReentrancyGuard { | ||
| error CallReverted(uint256 index, Call[] calls); | ||
| error InvalidCall(uint256 index, Call[] calls); | ||
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| address public constant DESTINATION_SETTLER = address(0xf00d); | ||
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| // Entrypoint function to be called by DestinationSettler contract on this chain. | ||
| // Assume user has 7702-delegated code already to this contract. | ||
| // All calldata and 7702 authorization data is assumed to have been emitted on the origin chain in am ERC7683 | ||
| // intent creation event. | ||
| function xExecute(CallByUser memory userCalls) external nonReentrant { | ||
| require(msg.sender == DESTINATION_SETTLER); | ||
| _attemptCalls(userCalls.calls); | ||
| } | ||
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| function _attemptCalls(Call[] memory calls) internal { | ||
| for (uint256 i = 0; i < calls.length; ++i) { | ||
| Call memory call = calls[i]; | ||
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| // If we are calling an EOA with calldata, assume target was incorrectly specified and revert. | ||
| if (call.callData.length > 0 && call.target.code.length == 0) { | ||
| revert InvalidCall(i, calls); | ||
| } | ||
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| (bool success,) = call.target.call{value: call.value}(call.callData); | ||
| if (!success) revert CallReverted(i, calls); | ||
| } | ||
| } | ||
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| // Used if the caller is trying to unwrap the native token to this contract. | ||
| receive() external payable {} | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,100 @@ | ||
| pragma solidity ^0.8.0; | ||
|
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| import {ReentrancyGuard} from "@openzeppelin/contracts/utils/ReentrancyGuard.sol"; | ||
| import {SignatureChecker} from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol"; | ||
| import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol"; | ||
| import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol"; | ||
| import {GaslessCrossChainOrder} from "./ERC7683.sol"; | ||
| import {CallByUser, Call} from "./Structs.sol"; | ||
|
|
||
| /** | ||
| * @notice Destination chain entrypoint contract for fillers relaying cross chain message containing delegated | ||
| * calldata. | ||
| * @dev The difference between this contract and the DestinationSettler.sol contract is that this contract | ||
| * performs all the CallByUser signature verification AND executes the user's calldata, rather than having | ||
| * the XAccount contract do it. This reduces gas costs in the `fill()` function but it does mean that all users | ||
| * must trust the DestinationSettler contract since it performs the signature verification. This contract is different | ||
| * from DestinationSettler2.sol because it collapses the XAccount and the DestinationSettler2 contracts into one. | ||
| */ | ||
| contract DestinationSettler3 is ReentrancyGuard { | ||
| using SafeERC20 for IERC20; | ||
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| mapping(bytes32 => bool) public fillStatuses; | ||
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| error CallReverted(uint256 index, Call[] calls); | ||
| error InvalidCall(uint256 index, Call[] calls); | ||
|
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| // Called by filler, who sees ERC7683 intent emitted on origin chain | ||
| // containing the callsByUser data to be executed following a 7702 delegation. | ||
| // @dev We don't use the last parameter `fillerData` in this function. | ||
| function fill(bytes32 orderId, bytes calldata originData, bytes calldata) external nonReentrant { | ||
| (CallByUser memory callsByUser) = abi.decode(originData, (CallByUser)); | ||
| // Verify orderId? | ||
| // require(orderId == keccak256(originData), "Wrong order data"); | ||
|
|
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| // Protect against duplicate fills. | ||
| require(!fillStatuses[orderId], "Already filled"); | ||
| fillStatuses[orderId] = true; | ||
|
|
||
| // TODO: Protect fillers from collisions with other fillers. Requires letting user set an exclusive relayer. | ||
|
|
||
| // Pull funds into this settlement contract and perform any steps necessary to ensure that filler | ||
| // receives a refund of their assets. | ||
| _fundUser(callsByUser); | ||
|
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| _verifyCalls(callsByUser); | ||
| _verify7702Delegation(); | ||
|
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| // The following call might fail if the user has not set a 7702 authorization to set its code | ||
| // equal to this contract. Without this authorization, the msg.sender will not be the userCalls.user. | ||
| // The filler should have seen any auth data emitted in an OriginSettler event on the sending chain. | ||
| _attemptCalls(callsByUser.calls); | ||
|
|
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| // Perform any final steps required to prove that filler has successfully filled the ERC7683 intent. | ||
| // For example, we could emit an event containing a unique hash of the fill that could be proved | ||
| // on the origin chain via a receipt proof + RIP7755. | ||
| // e.g. emit Executed(orderId) | ||
| } | ||
|
|
||
| // Pull funds into this settlement contract as escrow and use to execute user's calldata. Escrowed | ||
| // funds will be paid back to filler after this contract successfully verifies the settled intent. | ||
| // This step could be skipped by lightweight escrow systems that don't need to perform additional | ||
| // validation on the filler's actions. | ||
| function _fundUser(CallByUser memory call) internal { | ||
| IERC20(call.asset.token).safeTransferFrom(msg.sender, call.user, call.asset.amount); | ||
| } | ||
|
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| function _verifyCalls(CallByUser memory userCalls) internal view { | ||
| require(userCalls.chainId == block.chainid); | ||
| // TODO: Make the blob to sign EIP712-compatible (i.e. instead of keccak256(abi.encode(...)) set | ||
| // this to SigningLib.getTypedDataHash(...) | ||
| require( | ||
| SignatureChecker.isValidSignatureNow( | ||
| userCalls.user, keccak256(abi.encode(userCalls.calls, userCalls.nonce)), userCalls.signature | ||
| ) | ||
| ); | ||
| } | ||
|
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| function _verify7702Delegation() internal { | ||
| // TODO: We might not need this function at all, because if the authorization data requires that this contract | ||
| // is set as the delegation code, then xExecute would fail if the auth data is not submitted by the filler. | ||
| // However, it might still be useful to verify that the delegate is set correctly, like checking EXTCODEHASH. | ||
| } | ||
|
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| function _attemptCalls(Call[] memory calls) internal { | ||
| for (uint256 i = 0; i < calls.length; ++i) { | ||
| Call memory call = calls[i]; | ||
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| // If we are calling an EOA with calldata, assume target was incorrectly specified and revert. | ||
| if (call.callData.length > 0 && call.target.code.length == 0) { | ||
| revert InvalidCall(i, calls); | ||
| } | ||
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| (bool success,) = call.target.call{value: call.value}(call.callData); | ||
| if (!success) revert CallReverted(i, calls); | ||
| } | ||
| } | ||
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| // Used if the caller is trying to unwrap the native token to this contract. | ||
| receive() external payable {} | ||
| } |