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Diffstat (limited to 'packages/contracts/contracts/protocol/Exchange/MixinTransactions.sol')
-rw-r--r-- | packages/contracts/contracts/protocol/Exchange/MixinTransactions.sol | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/packages/contracts/contracts/protocol/Exchange/MixinTransactions.sol b/packages/contracts/contracts/protocol/Exchange/MixinTransactions.sol new file mode 100644 index 000000000..3a76ca202 --- /dev/null +++ b/packages/contracts/contracts/protocol/Exchange/MixinTransactions.sol @@ -0,0 +1,152 @@ +/* + + Copyright 2018 ZeroEx Intl. + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + +*/ +pragma solidity 0.4.24; + +import "./libs/LibExchangeErrors.sol"; +import "./mixins/MSignatureValidator.sol"; +import "./mixins/MTransactions.sol"; +import "./libs/LibEIP712.sol"; + + +contract MixinTransactions is + LibEIP712, + MSignatureValidator, + MTransactions +{ + // Mapping of transaction hash => executed + // This prevents transactions from being executed more than once. + mapping (bytes32 => bool) public transactions; + + // Address of current transaction signer + address public currentContextAddress; + + /// @dev Executes an exchange method call in the context of signer. + /// @param salt Arbitrary number to ensure uniqueness of transaction hash. + /// @param signerAddress Address of transaction signer. + /// @param data AbiV2 encoded calldata. + /// @param signature Proof of signer transaction by signer. + function executeTransaction( + uint256 salt, + address signerAddress, + bytes data, + bytes signature + ) + external + { + // Prevent reentrancy + require( + currentContextAddress == address(0), + "REENTRANCY_ILLEGAL" + ); + + bytes32 transactionHash = hashEIP712Message(hashZeroExTransaction( + salt, + signerAddress, + data + )); + + // Validate transaction has not been executed + require( + !transactions[transactionHash], + "INVALID_TX_HASH" + ); + + // Transaction always valid if signer is sender of transaction + if (signerAddress != msg.sender) { + // Validate signature + require( + isValidSignature( + transactionHash, + signerAddress, + signature + ), + "INVALID_TX_SIGNATURE" + ); + + // Set the current transaction signer + currentContextAddress = signerAddress; + } + + // Execute transaction + transactions[transactionHash] = true; + require( + address(this).delegatecall(data), + "FAILED_EXECUTION" + ); + + // Reset current transaction signer if it was previously updated + if (signerAddress != msg.sender) { + currentContextAddress = address(0); + } + } + + /// @dev Calculates EIP712 hash of the Transaction. + /// @param salt Arbitrary number to ensure uniqueness of transaction hash. + /// @param signerAddress Address of transaction signer. + /// @param data AbiV2 encoded calldata. + /// @return EIP712 hash of the Transaction. + function hashZeroExTransaction( + uint256 salt, + address signerAddress, + bytes memory data + ) + internal + pure + returns (bytes32 result) + { + bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH; + bytes32 dataHash = keccak256(data); + + // Assembly for more efficiently computing: + // keccak256(abi.encodePacked( + // EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH, + // salt, + // bytes32(signerAddress), + // keccak256(data) + // )); + + assembly { + // Load free memory pointer + let memPtr := mload(64) + + mstore(memPtr, schemaHash) // hash of schema + mstore(add(memPtr, 32), salt) // salt + mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff)) // signerAddress + mstore(add(memPtr, 96), dataHash) // hash of data + + // Compute hash + result := keccak256(memPtr, 128) + } + return result; + } + + /// @dev The current function will be called in the context of this address (either 0x transaction signer or `msg.sender`). + /// If calling a fill function, this address will represent the taker. + /// If calling a cancel function, this address will represent the maker. + /// @return Signer of 0x transaction if entry point is `executeTransaction`. + /// `msg.sender` if entry point is any other function. + function getCurrentContextAddress() + internal + view + returns (address) + { + address currentContextAddress_ = currentContextAddress; + address contextAddress = currentContextAddress_ == address(0) ? msg.sender : currentContextAddress_; + return contextAddress; + } +} |