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author | Amir Bandeali <abandeali1@gmail.com> | 2018-06-27 10:12:43 +0800 |
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committer | Amir Bandeali <abandeali1@gmail.com> | 2018-06-30 09:05:40 +0800 |
commit | 2fcc36bbadcb8238ee292afc58c2cd460d1b69da (patch) | |
tree | 235d3f2b361194a2e9ba41c4981a35daa99ac863 /packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol | |
parent | 762c0143eb10306ca70b0f206e80eb9aed925f99 (diff) | |
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Update file structure
Diffstat (limited to 'packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol')
-rw-r--r-- | packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol new file mode 100644 index 000000000..31f7f2847 --- /dev/null +++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol @@ -0,0 +1,154 @@ +/* + + 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; + + // Hash for the EIP712 ZeroEx Transaction Schema + bytes32 constant EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH = keccak256(abi.encodePacked( + "ZeroExTransaction(", + "uint256 salt,", + "address signerAddress,", + "bytes data", + ")" + )); + + /// @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.encode( + // EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH, + // salt, + // signerAddress, + // keccak256(data) + // )); + assembly { + let memPtr := mload(64) + mstore(memPtr, schemaHash) + mstore(add(memPtr, 32), salt) + mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff)) + mstore(add(memPtr, 96), dataHash) + result := keccak256(memPtr, 128) + } + + return result; + } + + /// @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 + // TODO: Check if gas is paid when currentContextAddress is already 0. + currentContextAddress = address(0); + } + + /// @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 contextAddress = currentContextAddress == address(0) ? msg.sender : currentContextAddress; + return contextAddress; + } +} |