GnosisSafe.sol
// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.7.0 <0.9.0;
import "./base/ModuleManager.sol";
import "./base/OwnerManager.sol";
import "./base/FallbackManager.sol";
import "./base/GuardManager.sol";
import "./common/EtherPaymentFallback.sol";
import "./common/Singleton.sol";
import "./common/SignatureDecoder.sol";
import "./common/SecuredTokenTransfer.sol";
import "./common/StorageAccessible.sol";
import "./interfaces/ISignatureValidator.sol";
import "./external/GnosisSafeMath.sol";
/// @title Gnosis Safe - A multisignature wallet with support for confirmations using signed messages based on ERC191.
/// @author Stefan George - <stefan@gnosis.io>
/// @author Richard Meissner - <richard@gnosis.io>
contract GnosisSafe is
EtherPaymentFallback,
Singleton,
ModuleManager,
OwnerManager,
SignatureDecoder,
SecuredTokenTransfer,
ISignatureValidatorConstants,
FallbackManager,
StorageAccessible,
GuardManager
{
using GnosisSafeMath for uint256;
string public constant VERSION = "1.3.0";
// keccak256(
// "EIP712Domain(uint256 chainId,address verifyingContract)"
// );
bytes32 private constant DOMAIN_SEPARATOR_TYPEHASH = 0x47e79534a245952e8b16893a336b85a3d9ea9fa8c573f3d803afb92a79469218;
// keccak256(
// "SafeTx(address to,uint256 value,bytes data,uint8 operation,uint256 safeTxGas,uint256 baseGas,uint256 gasPrice,address gasToken,address refundReceiver,uint256 nonce)"
// );
bytes32 private constant SAFE_TX_TYPEHASH = 0xbb8310d486368db6bd6f849402fdd73ad53d316b5a4b2644ad6efe0f941286d8;
event SafeSetup(address indexed initiator, address[] owners, uint256 threshold, address initializer, address fallbackHandler);
event ApproveHash(bytes32 indexed approvedHash, address indexed owner);
event SignMsg(bytes32 indexed msgHash);
event ExecutionFailure(bytes32 txHash, uint256 payment);
event ExecutionSuccess(bytes32 txHash, uint256 payment);
uint256 public nonce;
bytes32 private _deprecatedDomainSeparator;
// Mapping to keep track of all message hashes that have been approved by ALL REQUIRED owners
mapping(bytes32 => uint256) public signedMessages;
// Mapping to keep track of all hashes (message or transaction) that have been approved by ANY owners
mapping(address => mapping(bytes32 => uint256)) public approvedHashes;
// This constructor ensures that this contract can only be used as a master copy for Proxy contracts
constructor() {
// By setting the threshold it is not possible to call setup anymore,
// so we create a Safe with 0 owners and threshold 1.
// This is an unusable Safe, perfect for the singleton
threshold = 1;
}
/// @dev Setup function sets initial storage of contract.
/// @param _owners List of Safe owners.
/// @param _threshold Number of required confirmations for a Safe transaction.
/// @param to Contract address for optional delegate call.
/// @param data Data payload for optional delegate call.
/// @param fallbackHandler Handler for fallback calls to this contract
/// @param paymentToken Token that should be used for the payment (0 is ETH)
/// @param payment Value that should be paid
/// @param paymentReceiver Address that should receive the payment (or 0 if tx.origin)
function setup(
address[] calldata _owners,
uint256 _threshold,
address to,
bytes calldata data,
address fallbackHandler,
address paymentToken,
uint256 payment,
address payable paymentReceiver
) external {
// setupOwners checks if the Threshold is already set, therefore preventing that this method is called twice
setupOwners(_owners, _threshold);
if (fallbackHandler != address(0)) internalSetFallbackHandler(fallbackHandler);
// As setupOwners can only be called if the contract has not been initialized we don't need a check for setupModules
setupModules(to, data);
if (payment > 0) {
// To avoid running into issues with EIP-170 we reuse the handlePayment function (to avoid adjusting code of that has been verified we do not adjust the method itself)
// baseGas = 0, gasPrice = 1 and gas = payment => amount = (payment + 0) * 1 = payment
handlePayment(payment, 0, 1, paymentToken, paymentReceiver);
}
emit SafeSetup(msg.sender, _owners, _threshold, to, fallbackHandler);
}
/// @dev Allows to execute a Safe transaction confirmed by required number of owners and then pays the account that submitted the transaction.
/// Note: The fees are always transferred, even if the user transaction fails.
/// @param to Destination address of Safe transaction.
/// @param value Ether value of Safe transaction.
/// @param data Data payload of Safe transaction.
/// @param operation Operation type of Safe transaction.
/// @param safeTxGas Gas that should be used for the Safe transaction.
/// @param baseGas Gas costs that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
/// @param gasPrice Gas price that should be used for the payment calculation.
/// @param gasToken Token address (or 0 if ETH) that is used for the payment.
/// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
/// @param signatures Packed signature data ({bytes32 r}{bytes32 s}{uint8 v})
function execTransaction(
address to,
uint256 value,
bytes calldata data,
Enum.Operation operation,
uint256 safeTxGas,
uint256 baseGas,
uint256 gasPrice,
address gasToken,
address payable refundReceiver,
bytes memory signatures
) public payable virtual returns (bool success) {
bytes32 txHash;
// Use scope here to limit variable lifetime and prevent `stack too deep` errors
{
bytes memory txHashData =
encodeTransactionData(
// Transaction info
to,
value,
data,
operation,
safeTxGas,
// Payment info
baseGas,
gasPrice,
gasToken,
refundReceiver,
// Signature info
nonce
);
// Increase nonce and execute transaction.
nonce++;
txHash = keccak256(txHashData);
checkSignatures(txHash, txHashData, signatures);
}
address guard = getGuard();
{
if (guard != address(0)) {
Guard(guard).checkTransaction(
// Transaction info
to,
value,
data,
operation,
safeTxGas,
// Payment info
baseGas,
gasPrice,
gasToken,
refundReceiver,
// Signature info
signatures,
msg.sender
);
}
}
// We require some gas to emit the events (at least 2500) after the execution and some to perform code until the execution (500)
// We also include the 1/64 in the check that is not send along with a call to counteract potential shortings because of EIP-150
require(gasleft() >= ((safeTxGas * 64) / 63).max(safeTxGas + 2500) + 500, "GS010");
// Use scope here to limit variable lifetime and prevent `stack too deep` errors
{
uint256 gasUsed = gasleft();
// If the gasPrice is 0 we assume that nearly all available gas can be used (it is always more than safeTxGas)
// We only substract 2500 (compared to the 3000 before) to ensure that the amount passed is still higher than safeTxGas
success = execute(to, value, data, operation, gasPrice == 0 ? (gasleft() - 2500) : safeTxGas);
gasUsed = gasUsed.sub(gasleft());
// If no safeTxGas and no gasPrice was set (e.g. both are 0), then the internal tx is required to be successful
// This makes it possible to use `estimateGas` without issues, as it searches for the minimum gas where the tx doesn't revert
require(success || safeTxGas != 0 || gasPrice != 0, "GS013");
// We transfer the calculated tx costs to the tx.origin to avoid sending it to intermediate contracts that have made calls
uint256 payment = 0;
if (gasPrice > 0) {
payment = handlePayment(gasUsed, baseGas, gasPrice, gasToken, refundReceiver);
}
if (success) emit ExecutionSuccess(txHash, payment);
else emit ExecutionFailure(txHash, payment);
}
{
if (guard != address(0)) {
Guard(guard).checkAfterExecution(txHash, success);
}
}
}
function handlePayment(
uint256 gasUsed,
uint256 baseGas,
uint256 gasPrice,
address gasToken,
address payable refundReceiver
) private returns (uint256 payment) {
// solhint-disable-next-line avoid-tx-origin
address payable receiver = refundReceiver == address(0) ? payable(tx.origin) : refundReceiver;
if (gasToken == address(0)) {
// For ETH we will only adjust the gas price to not be higher than the actual used gas price
payment = gasUsed.add(baseGas).mul(gasPrice < tx.gasprice ? gasPrice : tx.gasprice);
require(receiver.send(payment), "GS011");
} else {
payment = gasUsed.add(baseGas).mul(gasPrice);
require(transferToken(gasToken, receiver, payment), "GS012");
}
}
/**
* @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
* @param dataHash Hash of the data (could be either a message hash or transaction hash)
* @param data That should be signed (this is passed to an external validator contract)
* @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
*/
function checkSignatures(
bytes32 dataHash,
bytes memory data,
bytes memory signatures
) public view {
// Load threshold to avoid multiple storage loads
uint256 _threshold = threshold;
// Check that a threshold is set
require(_threshold > 0, "GS001");
checkNSignatures(dataHash, data, signatures, _threshold);
}
/**
* @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
* @param dataHash Hash of the data (could be either a message hash or transaction hash)
* @param data That should be signed (this is passed to an external validator contract)
* @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
* @param requiredSignatures Amount of required valid signatures.
*/
function checkNSignatures(
bytes32 dataHash,
bytes memory data,
bytes memory signatures,
uint256 requiredSignatures
) public view {
// Check that the provided signature data is not too short
require(signatures.length >= requiredSignatures.mul(65), "GS020");
// There cannot be an owner with address 0.
address lastOwner = address(0);
address currentOwner;
uint8 v;
bytes32 r;
bytes32 s;
uint256 i;
for (i = 0; i < requiredSignatures; i++) {
(v, r, s) = signatureSplit(signatures, i);
if (v == 0) {
// If v is 0 then it is a contract signature
// When handling contract signatures the address of the contract is encoded into r
currentOwner = address(uint160(uint256(r)));
// Check that signature data pointer (s) is not pointing inside the static part of the signatures bytes
// This check is not completely accurate, since it is possible that more signatures than the threshold are send.
// Here we only check that the pointer is not pointing inside the part that is being processed
require(uint256(s) >= requiredSignatures.mul(65), "GS021");
// Check that signature data pointer (s) is in bounds (points to the length of data -> 32 bytes)
require(uint256(s).add(32) <= signatures.length, "GS022");
// Check if the contract signature is in bounds: start of data is s + 32 and end is start + signature length
uint256 contractSignatureLen;
// solhint-disable-next-line no-inline-assembly
assembly {
contractSignatureLen := mload(add(add(signatures, s), 0x20))
}
require(uint256(s).add(32).add(contractSignatureLen) <= signatures.length, "GS023");
// Check signature
bytes memory contractSignature;
// solhint-disable-next-line no-inline-assembly
assembly {
// The signature data for contract signatures is appended to the concatenated signatures and the offset is stored in s
contractSignature := add(add(signatures, s), 0x20)
}
require(ISignatureValidator(currentOwner).isValidSignature(data, contractSignature) == EIP1271_MAGIC_VALUE, "GS024");
} else if (v == 1) {
// If v is 1 then it is an approved hash
// When handling approved hashes the address of the approver is encoded into r
currentOwner = address(uint160(uint256(r)));
// Hashes are automatically approved by the sender of the message or when they have been pre-approved via a separate transaction
require(msg.sender == currentOwner || approvedHashes[currentOwner][dataHash] != 0, "GS025");
} else if (v > 30) {
// If v > 30 then default va (27,28) has been adjusted for eth_sign flow
// To support eth_sign and similar we adjust v and hash the messageHash with the Ethereum message prefix before applying ecrecover
currentOwner = ecrecover(keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", dataHash)), v - 4, r, s);
} else {
// Default is the ecrecover flow with the provided data hash
// Use ecrecover with the messageHash for EOA signatures
currentOwner = ecrecover(dataHash, v, r, s);
}
require(currentOwner > lastOwner && owners[currentOwner] != address(0) && currentOwner != SENTINEL_OWNERS, "GS026");
lastOwner = currentOwner;
}
}
/// @dev Allows to estimate a Safe transaction.
/// This method is only meant for estimation purpose, therefore the call will always revert and encode the result in the revert data.
/// Since the `estimateGas` function includes refunds, call this method to get an estimated of the costs that are deducted from the safe with `execTransaction`
/// @param to Destination address of Safe transaction.
/// @param value Ether value of Safe transaction.
/// @param data Data payload of Safe transaction.
/// @param operation Operation type of Safe transaction.
/// @return Estimate without refunds and overhead fees (base transaction and payload data gas costs).
/// @notice Deprecated in favor of common/StorageAccessible.sol and will be removed in next version.
function requiredTxGas(
address to,
uint256 value,
bytes calldata data,
Enum.Operation operation
) external returns (uint256) {
uint256 startGas = gasleft();
// We don't provide an error message here, as we use it to return the estimate
require(execute(to, value, data, operation, gasleft()));
uint256 requiredGas = startGas - gasleft();
// Convert response to string and return via error message
revert(string(abi.encodePacked(requiredGas)));
}
/**
* @dev Marks a hash as approved. This can be used to validate a hash that is used by a signature.
* @param hashToApprove The hash that should be marked as approved for signatures that are verified by this contract.
*/
function approveHash(bytes32 hashToApprove) external {
require(owners[msg.sender] != address(0), "GS030");
approvedHashes[msg.sender][hashToApprove] = 1;
emit ApproveHash(hashToApprove, msg.sender);
}
/// @dev Returns the chain id used by this contract.
function getChainId() public view returns (uint256) {
uint256 id;
// solhint-disable-next-line no-inline-assembly
assembly {
id := chainid()
}
return id;
}
function domainSeparator() public view returns (bytes32) {
return keccak256(abi.encode(DOMAIN_SEPARATOR_TYPEHASH, getChainId(), this));
}
/// @dev Returns the bytes that are hashed to be signed by owners.
/// @param to Destination address.
/// @param value Ether value.
/// @param data Data payload.
/// @param operation Operation type.
/// @param safeTxGas Gas that should be used for the safe transaction.
/// @param baseGas Gas costs for that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
/// @param gasPrice Maximum gas price that should be used for this transaction.
/// @param gasToken Token address (or 0 if ETH) that is used for the payment.
/// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
/// @param _nonce Transaction nonce.
/// @return Transaction hash bytes.
function encodeTransactionData(
address to,
uint256 value,
bytes calldata data,
Enum.Operation operation,
uint256 safeTxGas,
uint256 baseGas,
uint256 gasPrice,
address gasToken,
address refundReceiver,
uint256 _nonce
) public view returns (bytes memory) {
bytes32 safeTxHash =
keccak256(
abi.encode(
SAFE_TX_TYPEHASH,
to,
value,
keccak256(data),
operation,
safeTxGas,
baseGas,
gasPrice,
gasToken,
refundReceiver,
_nonce
)
);
return abi.encodePacked(bytes1(0x19), bytes1(0x01), domainSeparator(), safeTxHash);
}
/// @dev Returns hash to be signed by owners.
/// @param to Destination address.
/// @param value Ether value.
/// @param data Data payload.
/// @param operation Operation type.
/// @param safeTxGas Fas that should be used for the safe transaction.
/// @param baseGas Gas costs for data used to trigger the safe transaction.
/// @param gasPrice Maximum gas price that should be used for this transaction.
/// @param gasToken Token address (or 0 if ETH) that is used for the payment.
/// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
/// @param _nonce Transaction nonce.
/// @return Transaction hash.
function getTransactionHash(
address to,
uint256 value,
bytes calldata data,
Enum.Operation operation,
uint256 safeTxGas,
uint256 baseGas,
uint256 gasPrice,
address gasToken,
address refundReceiver,
uint256 _nonce
) public view returns (bytes32) {
return keccak256(encodeTransactionData(to, value, data, operation, safeTxGas, baseGas, gasPrice, gasToken, refundReceiver, _nonce));
}
}
GnosisSafeL2.sol
// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.7.0 <0.9.0;
import "./GnosisSafe.sol";
/// @title Gnosis Safe - A multisignature wallet with support for confirmations using signed messages based on ERC191.
/// @author Stefan George - <stefan@gnosis.io>
/// @author Richard Meissner - <richard@gnosis.io>
contract GnosisSafeL2 is GnosisSafe {
event SafeMultiSigTransaction(
address to,
uint256 value,
bytes data,
Enum.Operation operation,
uint256 safeTxGas,
uint256 baseGas,
uint256 gasPrice,
address gasToken,
address payable refundReceiver,
bytes signatures,
// We combine nonce, sender and threshold into one to avoid stack too deep
// Dev note: additionalInfo should not contain `bytes`, as this complicates decoding
bytes additionalInfo
);
event SafeModuleTransaction(address module, address to, uint256 value, bytes data, Enum.Operation operation);
/// @dev Allows to execute a Safe transaction confirmed by required number of owners and then pays the account that submitted the transaction.
/// Note: The fees are always transferred, even if the user transaction fails.
/// @param to Destination address of Safe transaction.
/// @param value Ether value of Safe transaction.
/// @param data Data payload of Safe transaction.
/// @param operation Operation type of Safe transaction.
/// @param safeTxGas Gas that should be used for the Safe transaction.
/// @param baseGas Gas costs that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
/// @param gasPrice Gas price that should be used for the payment calculation.
/// @param gasToken Token address (or 0 if ETH) that is used for the payment.
/// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
/// @param signatures Packed signature data ({bytes32 r}{bytes32 s}{uint8 v})
function execTransaction(
address to,
uint256 value,
bytes calldata data,
Enum.Operation operation,
uint256 safeTxGas,
uint256 baseGas,
uint256 gasPrice,
address gasToken,
address payable refundReceiver,
bytes memory signatures
) public payable override returns (bool) {
bytes memory additionalInfo;
{
additionalInfo = abi.encode(nonce, msg.sender, threshold);
}
emit SafeMultiSigTransaction(
to,
value,
data,
operation,
safeTxGas,
baseGas,
gasPrice,
gasToken,
refundReceiver,
signatures,
additionalInfo
);
return super.execTransaction(to, value, data, operation, safeTxGas, baseGas, gasPrice, gasToken, refundReceiver, signatures);
}
/// @dev Allows a Module to execute a Safe transaction without any further confirmations.
/// @param to Destination address of module transaction.
/// @param value Ether value of module transaction.
/// @param data Data payload of module transaction.
/// @param operation Operation type of module transaction.
function execTransactionFromModule(
address to,
uint256 value,
bytes memory data,
Enum.Operation operation
) public override returns (bool success) {
emit SafeModuleTransaction(msg.sender, to, value, data, operation);
success = super.execTransactionFromModule(to, value, data, operation);
}
}
GnosisSafeProxyFactory.sol
// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.7.0 <0.9.0;
import "./GnosisSafeProxy.sol";
import "./IProxyCreationCallback.sol";
/// @title Proxy Factory - Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
/// @author Stefan George - <stefan@gnosis.pm>
contract GnosisSafeProxyFactory {
event ProxyCreation(GnosisSafeProxy proxy, address singleton);
/// @dev Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
/// @param singleton Address of singleton contract.
/// @param data Payload for message call sent to new proxy contract.
function createProxy(address singleton, bytes memory data) public returns (GnosisSafeProxy proxy) {
proxy = new GnosisSafeProxy(singleton);
if (data.length > 0)
// solhint-disable-next-line no-inline-assembly
assembly {
if eq(call(gas(), proxy, 0, add(data, 0x20), mload(data), 0, 0), 0) {
revert(0, 0)
}
}
emit ProxyCreation(proxy, singleton);
}
/// @dev Allows to retrieve the runtime code of a deployed Proxy. This can be used to check that the expected Proxy was deployed.
function proxyRuntimeCode() public pure returns (bytes memory) {
return type(GnosisSafeProxy).runtimeCode;
}
/// @dev Allows to retrieve the creation code used for the Proxy deployment. With this it is easily possible to calculate predicted address.
function proxyCreationCode() public pure returns (bytes memory) {
return type(GnosisSafeProxy).creationCode;
}
/// @dev Allows to create new proxy contact using CREATE2 but it doesn't run the initializer.
/// This method is only meant as an utility to be called from other methods
/// @param _singleton Address of singleton contract.
/// @param initializer Payload for message call sent to new proxy contract.
/// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
function deployProxyWithNonce(
address _singleton,
bytes memory initializer,
uint256 saltNonce
) internal returns (GnosisSafeProxy proxy) {
// If the initializer changes the proxy address should change too. Hashing the initializer data is cheaper than just concatinating it
bytes32 salt = keccak256(abi.encodePacked(keccak256(initializer), saltNonce));
bytes memory deploymentData = abi.encodePacked(type(GnosisSafeProxy).creationCode, uint256(uint160(_singleton)));
// solhint-disable-next-line no-inline-assembly
assembly {
proxy := create2(0x0, add(0x20, deploymentData), mload(deploymentData), salt)
}
require(address(proxy) != address(0), "Create2 call failed");
}
/// @dev Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
/// @param _singleton Address of singleton contract.
/// @param initializer Payload for message call sent to new proxy contract.
/// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
function createProxyWithNonce(
address _singleton,
bytes memory initializer,
uint256 saltNonce
) public returns (GnosisSafeProxy proxy) {
proxy = deployProxyWithNonce(_singleton, initializer, saltNonce);
if (initializer.length > 0)
// solhint-disable-next-line no-inline-assembly
assembly {
if eq(call(gas(), proxy, 0, add(initializer, 0x20), mload(initializer), 0, 0), 0) {
revert(0, 0)
}
}
emit ProxyCreation(proxy, _singleton);
}
/// @dev Allows to create new proxy contact, execute a message call to the new proxy and call a specified callback within one transaction
/// @param _singleton Address of singleton contract.
/// @param initializer Payload for message call sent to new proxy contract.
/// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
/// @param callback Callback that will be invoked after the new proxy contract has been successfully deployed and initialized.
function createProxyWithCallback(
address _singleton,
bytes memory initializer,
uint256 saltNonce,
IProxyCreationCallback callback
) public returns (GnosisSafeProxy proxy) {
uint256 saltNonceWithCallback = uint256(keccak256(abi.encodePacked(saltNonce, callback)));
proxy = createProxyWithNonce(_singleton, initializer, saltNonceWithCallback);
if (address(callback) != address(0)) callback.proxyCreated(proxy, _singleton, initializer, saltNonce);
}
/// @dev Allows to get the address for a new proxy contact created via `createProxyWithNonce`
/// This method is only meant for address calculation purpose when you use an initializer that would revert,
/// therefore the response is returned with a revert. When calling this method set `from` to the address of the proxy factory.
/// @param _singleton Address of singleton contract.
/// @param initializer Payload for message call sent to new proxy contract.
/// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
function calculateCreateProxyWithNonceAddress(
address _singleton,
bytes calldata initializer,
uint256 saltNonce
) external returns (GnosisSafeProxy proxy) {
proxy = deployProxyWithNonce(_singleton, initializer, saltNonce);
revert(string(abi.encodePacked(proxy)));
}
}
GnosisSafeProxy.sol
// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.7.0 <0.9.0;
/// @title IProxy - Helper interface to access masterCopy of the Proxy on-chain
/// @author Richard Meissner - <richard@gnosis.io>
interface IProxy {
function masterCopy() external view returns (address);
}
/// @title GnosisSafeProxy - Generic proxy contract allows to execute all transactions applying the code of a master contract.
/// @author Stefan George - <stefan@gnosis.io>
/// @author Richard Meissner - <richard@gnosis.io>
contract GnosisSafeProxy {
// singleton always needs to be first declared variable, to ensure that it is at the same location in the contracts to which calls are delegated.
// To reduce deployment costs this variable is internal and needs to be retrieved via `getStorageAt`
address internal singleton;
/// @dev Constructor function sets address of singleton contract.
/// @param _singleton Singleton address.
constructor(address _singleton) {
require(_singleton != address(0), "Invalid singleton address provided");
singleton = _singleton;
}
/// @dev Fallback function forwards all transactions and returns all received return data.
fallback() external payable {
// solhint-disable-next-line no-inline-assembly
assembly {
let _singleton := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
// 0xa619486e == keccak("masterCopy()"). The value is right padded to 32-bytes with 0s
if eq(calldataload(0), 0xa619486e00000000000000000000000000000000000000000000000000000000) {
mstore(0, _singleton)
return(0, 0x20)
}
calldatacopy(0, 0, calldatasize())
let success := delegatecall(gas(), _singleton, 0, calldatasize(), 0, 0)
returndatacopy(0, 0, returndatasize())
if eq(success, 0) {
revert(0, returndatasize())
}
return(0, returndatasize())
}
}
}