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Diffstat (limited to 'packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol')
| -rw-r--r-- | packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol new file mode 100644 index 000000000..29172057a --- /dev/null +++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol @@ -0,0 +1,255 @@ +/* + + 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 "../../utils/LibBytes/LibBytes.sol"; +import "./mixins/MSignatureValidator.sol"; +import "./mixins/MTransactions.sol"; +import "./interfaces/IWallet.sol"; +import "./interfaces/IValidator.sol"; + +contract MixinSignatureValidator is + MSignatureValidator, + MTransactions +{ + using LibBytes for bytes; + + // Mapping of hash => signer => signed + mapping (bytes32 => mapping (address => bool)) public preSigned; + + // Mapping of signer => validator => approved + mapping (address => mapping (address => bool)) public allowedValidators; + + /// @dev Approves a hash on-chain using any valid signature type. + /// After presigning a hash, the preSign signature type will become valid for that hash and signer. + /// @param signerAddress Address that should have signed the given hash. + /// @param signature Proof that the hash has been signed by signer. + function preSign( + bytes32 hash, + address signerAddress, + bytes signature + ) + external + { + require( + isValidSignature( + hash, + signerAddress, + signature + ), + "INVALID_SIGNATURE" + ); + preSigned[hash][signerAddress] = true; + } + + /// @dev Approves/unnapproves a Validator contract to verify signatures on signer's behalf. + /// @param validatorAddress Address of Validator contract. + /// @param approval Approval or disapproval of Validator contract. + function setSignatureValidatorApproval( + address validatorAddress, + bool approval + ) + external + { + address signerAddress = getCurrentContextAddress(); + allowedValidators[signerAddress][validatorAddress] = approval; + emit SignatureValidatorApproval( + signerAddress, + validatorAddress, + approval + ); + } + + /// @dev Verifies that a hash has been signed by the given signer. + /// @param hash Any 32 byte hash. + /// @param signerAddress Address that should have signed the given hash. + /// @param signature Proof that the hash has been signed by signer. + /// @return True if the address recovered from the provided signature matches the input signer address. + function isValidSignature( + bytes32 hash, + address signerAddress, + bytes memory signature + ) + public + view + returns (bool isValid) + { + // TODO: Domain separation: make hash depend on role. (Taker sig should not be valid as maker sig, etc.) + require( + signature.length > 0, + "LENGTH_GREATER_THAN_0_REQUIRED" + ); + + // Ensure signature is supported + uint8 signatureTypeRaw = uint8(signature.popLastByte()); + require( + signatureTypeRaw < uint8(SignatureType.NSignatureTypes), + "SIGNATURE_UNSUPPORTED" + ); + + // Pop last byte off of signature byte array. + SignatureType signatureType = SignatureType(signatureTypeRaw); + + // Variables are not scoped in Solidity. + uint8 v; + bytes32 r; + bytes32 s; + address recovered; + + // Always illegal signature. + // This is always an implicit option since a signer can create a + // signature array with invalid type or length. We may as well make + // it an explicit option. This aids testing and analysis. It is + // also the initialization value for the enum type. + if (signatureType == SignatureType.Illegal) { + revert("SIGNATURE_ILLEGAL"); + + // Always invalid signature. + // Like Illegal, this is always implicitly available and therefore + // offered explicitly. It can be implicitly created by providing + // a correctly formatted but incorrect signature. + } else if (signatureType == SignatureType.Invalid) { + require( + signature.length == 0, + "LENGTH_0_REQUIRED" + ); + isValid = false; + return isValid; + + // Signature using EIP712 + } else if (signatureType == SignatureType.EIP712) { + require( + signature.length == 65, + "LENGTH_65_REQUIRED" + ); + v = uint8(signature[0]); + r = signature.readBytes32(1); + s = signature.readBytes32(33); + recovered = ecrecover(hash, v, r, s); + isValid = signerAddress == recovered; + return isValid; + + // Signed using web3.eth_sign + } else if (signatureType == SignatureType.EthSign) { + require( + signature.length == 65, + "LENGTH_65_REQUIRED" + ); + v = uint8(signature[0]); + r = signature.readBytes32(1); + s = signature.readBytes32(33); + recovered = ecrecover( + keccak256(abi.encodePacked( + "\x19Ethereum Signed Message:\n32", + hash + )), + v, + r, + s + ); + isValid = signerAddress == recovered; + return isValid; + + // Implicitly signed by caller. + // The signer has initiated the call. In the case of non-contract + // accounts it means the transaction itself was signed. + // Example: let's say for a particular operation three signatures + // A, B and C are required. To submit the transaction, A and B can + // give a signature to C, who can then submit the transaction using + // `Caller` for his own signature. Or A and C can sign and B can + // submit using `Caller`. Having `Caller` allows this flexibility. + } else if (signatureType == SignatureType.Caller) { + require( + signature.length == 0, + "LENGTH_0_REQUIRED" + ); + isValid = signerAddress == msg.sender; + return isValid; + + // Signature verified by wallet contract. + // If used with an order, the maker of the order is the wallet contract. + } else if (signatureType == SignatureType.Wallet) { + isValid = IWallet(signerAddress).isValidSignature(hash, signature); + return isValid; + + // Signature verified by validator contract. + // If used with an order, the maker of the order can still be an EOA. + // A signature using this type should be encoded as: + // | Offset | Length | Contents | + // | 0x00 | x | Signature to validate | + // | 0x00 + x | 20 | Address of validator contract | + // | 0x14 + x | 1 | Signature type is always "\x06" | + } else if (signatureType == SignatureType.Validator) { + // Pop last 20 bytes off of signature byte array. + + address validatorAddress = signature.popLast20Bytes(); + + // Ensure signer has approved validator. + if (!allowedValidators[signerAddress][validatorAddress]) { + return false; + } + isValid = IValidator(validatorAddress).isValidSignature( + hash, + signerAddress, + signature + ); + return isValid; + + // Signer signed hash previously using the preSign function. + } else if (signatureType == SignatureType.PreSigned) { + isValid = preSigned[hash][signerAddress]; + return isValid; + + // Signature from Trezor hardware wallet. + // It differs from web3.eth_sign in the encoding of message length + // (Bitcoin varint encoding vs ascii-decimal, the latter is not + // self-terminating which leads to ambiguities). + // See also: + // https://en.bitcoin.it/wiki/Protocol_documentation#Variable_length_integer + // https://github.com/trezor/trezor-mcu/blob/master/firmware/ethereum.c#L602 + // https://github.com/trezor/trezor-mcu/blob/master/firmware/crypto.c#L36 + } else if (signatureType == SignatureType.Trezor) { + require( + signature.length == 65, + "LENGTH_65_REQUIRED" + ); + v = uint8(signature[0]); + r = signature.readBytes32(1); + s = signature.readBytes32(33); + recovered = ecrecover( + keccak256(abi.encodePacked( + "\x19Ethereum Signed Message:\n\x20", + hash + )), + v, + r, + s + ); + isValid = signerAddress == recovered; + return isValid; + } + + // Anything else is illegal (We do not return false because + // the signature may actually be valid, just not in a format + // that we currently support. In this case returning false + // may lead the caller to incorrectly believe that the + // signature was invalid.) + revert("SIGNATURE_UNSUPPORTED"); + } +} |