Platform: Code4rena
Start Date: 12/07/2023
Pot Size: $80,000 USDC
Total HM: 11
Participants: 47
Period: 9 days
Judge: berndartmueller
Total Solo HM: 1
Id: 260
League: ETH
Rank: 21/47
Findings: 1
Award: $189.74
🌟 Selected for report: 0
🚀 Solo Findings: 0
🌟 Selected for report: Sathish9098
Also found by: 0x11singh99, 0xAnah, 0xn006e7, Arz, DavidGiladi, K42, Raihan, ReyAdmirado, Rolezn, SAQ, SM3_SS, SY_S, Walter, dharma09, flutter_developer, hunter_w3b, matrix_0wl, naman1778, petrichor, ybansal2403
189.7433 USDC - $189.74
| NO | Details | Instances |
|---|---|---|
| [G-01] | Use calldata instead of memory for function arguments that do not get mutated | 10 |
| [G-02] | Use do while loops instead of for loops | 1 |
| [G-03] | Cache state variables outside of loop to avoid reading storage on every iteration | 4 |
| [G-04] | With assembly, .call (bool success) transfer can be done gas-optimized | 5 |
| [G-05] | x += y costs more gas than x = x + y for state variables | 1 |
| [G-06] | If statements that use && can be refactored into nested if statements | 6 |
| [G-07] | Using XOR (^) and OR bitwise equivalents | 3 |
| [G-08] | Using a positive conditional flow to save a NOT opcode | 17 |
| [G-09] | Make 3 event parameters indexed when possible | 8 |
| [G-10] | Use constants instead of type(uintx).max | 10 |
| [G-11] | Using bools for storage incurs overhead | 6 |
| [G-12] | Amounts should be checked for 0 before calling a transfer | 9 |
| [G-13] | Don’t Initialize Variables with Default Value | 4 |
| [G-14] | abi.encode() is less efficient than abi.encodePacked() | 31 |
| [G-15] | Use hardcode address instead address(this) | 25 |
| [G-16] | A modifier used only once and not being inherited should be inlined to save gas | 8 |
| [G-17] | Use assembly for loops | 10 |
| [G-18] | Failure to check the zero address in the constructor causes the contract to be deployed again | 4 |
| [G-19] | Functions guaranteed to revert when called by normal users can be marked payable | 14 |
| [G-20] | Use assembly for math (add, sub, mul, div) | 4 |
| [G-21] | Use assembly when getting a contract’s balance of ETH | 1 |
| [G-22] | use Fixed-size Arrays are cheaper than dynamic one if it is possiable to save gas | 5 |
| [G-23] | Use assembly to perform efficient back-to-back calls | 2 |
| [G-24] | Use Modifiers Instead of Functions To Save Gas | 3 |
| [G-25] | Use custom errors rather than revert()/require() strings to save gas | 140 |
| [G-26] | Enable the Solidity Compiler Optimizer to save gas |
When you specify a data location as memory, that value will be copied into memory. When you specify the location as calldata, the value will stay static within calldata. If the value is a large, complex type, using memory may result in extra memory expansion costs.
file: contracts/cgp/auth/MultisigBase.sol 142 function rotateSigners(address[] memory newAccounts, uint256 newThreshold) external virtual onlySigners 149 function _rotateSigners(address[] memory newAccounts, uint256 newThreshold) internal {
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L142
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L149
file: contracts/cgp/interfaces/IMultisigBase.sol 73 function rotateSigners(address[] memory newAccounts, uint256 newThreshold) external;
file: contracts/gmp-sdk/deploy/ConstAddressDeployer.sol 42 function deployAndInit( bytes memory bytecode, bytes32 salt, bytes calldata init ) external returns
file: contracts/gmp-sdk/deploy/Create3.sol 21 function deploy(bytes memory bytecode) external
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/deploy/Create3.sol#L21
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 73 function _executeProposal(InterchainCalls.Call[] memory calls) internal
file: contracts/interchain-governance-executor/interfaces/IInterchainProposalSender.sol 15 function sendProposals(InterchainCalls.InterchainCall[] memory calls) external payable;
file: contracts/its/interchain-token-service/InterchainTokenService.sol 559 function _sanitizeTokenManagerImplementation(address[] memory implementaions, TokenManagerType tokenManagerType)
file: contracts/its/interfaces/IMulticall.sol 18 function multicall(bytes[] calldata data) external payable returns (bytes[] memory results);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/interfaces/IMulticall.sol#L18
file: contracts/its/utils/Multicall.sol 22 function multicall(bytes[] calldata data) public payable returns (bytes[] memory results)
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Multicall.sol#L22
file: 270 for (uint256 i; i < length; ++i) { string memory symbol = symbols[i]; uint256 limit = limits[i]; if (tokenAddresses(symbol) == address(0)) revert TokenDoesNotExist(symbol); _setTokenMintLimit(symbol, limit); }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L270-L277
function setTokenMintLimits(string[] calldata symbols, uint256[] calldata limits) external override onlyMintLimiter { uint256 length = symbols.length; if (length != limits.length) revert InvalidSetMintLimitsParams(); uint256 i = 0; do { string memory symbol = symbols[i]; uint256 limit = limits[i]; if (tokenAddresses(symbol) == address(0)) revert TokenDoesNotExist(symbol); _setTokenMintLimit(symbol, limit); i++; } while (i < length); }
Reading from storage should always try to be avoided within loops. In the following instances, we are able to cache state variables outside of the loop to save a Gwarmaccess (100 gas) per loop iteration.
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 108 for (uint256 i; i < length; ++i) { string calldata chainName = chainNames[i]; supportedByGateway[chainName] = true; emit GatewaySupportedChainAdded(chainName); } 119 function removeGatewaySupportedChains(string[] calldata chainNames) external onlyOwner { uint256 length = chainNames.length; for (uint256 i; i < length; ++i) { string calldata chainName = chainNames[i]; supportedByGateway[chainName] = false; emit GatewaySupportedChainRemoved(chainName); } }
file: contracts/cgp/auth/MultisigBase.sol 122 for (uint256 i; i < length; ++i) { if (votingPerTopic[signerEpoch][topic].hasVoted[signers.accounts[i]]) { voteCount++; } }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L122-L125
file: contracts/cgp/auth/MultisigBase.sol 70 for (uint256 i; i < count; ++i) { voting.hasVoted[signers.accounts[i]] = false; }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L70-L73
return data (bool success,) has to be stored due to EVM architecture, but in a usage like below, ‘out’ and ‘outsize’ values are given (0,0), this storage disappears and gas optimization is provided.
file: contracts/cgp/AxelarGateway.sol 374 (bool success, ) = address(this).call(abi.encodeWithSelector(commandSelector, params[i], commandId));
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L374
file: contracts/cgp/util/Caller.sol 18 (bool success, ) = target.call{ value: nativeValue }(callData);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/util/Caller.sol#L18
file: contracts/gmp-sdk/deploy/ConstAddressDeployer.sol 50 (bool success, ) = deployedAddress_.call(init);
file: contracts/gmp-sdk/deploy/Create3Deployer.sol 57 (bool success, ) = deployedAddress_.call(init);
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 76 (bool success, bytes memory result) = call.target.call{ value: call.value }(call.callData);
file: contracts/interchain-governance-executor/InterchainProposalSender.sol 107 totalGas += interchainCalls[i].gas;
file: contracts/cgp/AxelarGateway.sol 88 if (msg.sender != getAddress(KEY_MINT_LIMITER) && msg.sender != getAddress(KEY_GOVERNANCE)) revert NotMintLimiter(); 446 if (!success || (returnData.length != uint256(0) && !abi.decode(returnData, (bool)))) revert BurnFailed(symbol); 635 if (limit > 0 && amount > limit) revert ExceedMintLimit(symbol);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L88
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L446
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L635
file: contracts/gmp-sdk/upgradable/InitProxy.sol 50 if (id != bytes32(0) && IUpgradable(implementationAddress).contractId() != id) revert InvalidImplementation();
file: contracts/gmp-sdk/upgradable/Proxy.sol 33 if (id != bytes32(0) && IUpgradable(implementationAddress).contractId() != id) revert InvalidImplementation();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/upgradable/Proxy.sol#L33
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 58 if ((b >= 65) && (b <= 70)) bytes(s)[i] = bytes1(b + uint8(32));
Estimated savings: 73 gas
file: contracts/cgp/AxelarGateway.sol 342 if (commandsLength != commands.length || commandsLength != params.length) revert InvalidCommands(); 446 if (!success || (returnData.length != uint256(0) && !abi.decode(returnData, (bool)))) revert BurnFailed(symbol);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L342
file: contracts/cgp/governance/InterchainGovernance.sol 92 if (keccak256(bytes(sourceChain)) != governanceChainHash || keccak256(bytes(sourceAddress)) != governanceAddressHash)
file: contracts/cgp/AxelarGateway.sol 296 if (!success) revert SetupFailed(); 363 if (!allowOperatorshipTransfer) continue; 402 if (!success) revert TokenDeployFailed(symbol); 446 if (!success || (returnData.length != uint256(0) && !abi.decode(returnData, (bool)))) revert BurnFailed(symbol);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L296
file: contracts/cgp/auth/MultisigBase.sol 45 if (!signers.isSigner[msg.sender]) revert NotSigner();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L45
file: contracts/cgp/governance/AxelarServiceGovernance.sol 55 if (!multisigApprovals[proposalHash]) revert NotApproved();
file: contracts/cgp/util/Caller.sol 19 if (!success)
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/util/Caller.sol#L19
file: contracts/gmp-sdk/upgradable/Upgradable.sol 51 if (!success) revert SetupFailed();
file: contracts/gmp-sdk/deploy/ConstAddressDeployer.sol 51 if (!success) revert FailedInit();
file: contracts/gmp-sdk/deploy/Create3Deployer.sol 58 if (!success) revert FailedInit();
file: contracts/gmp-sdk/upgradable/FinalProxy.sol 82 if (!success) revert SetupFailed();
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 49 if (!whitelistedSenders[sourceChain][StringToAddress.toAddress(sourceAddress)]) 57 if (!whitelistedCallers[sourceChain][interchainProposalCaller]) 78 if (!success)
file: contracts/its/interchain-token-service/InterchainTokenService.sol 124 if (!remoteAddressValidator.validateSender(sourceChain, sourceAddress)) revert NotRemoteService(); 816 if (!success) 866 if (!success)
It’s the most gas efficient to make up to 3 event parameters indexed. If there are less than 3 parameters, you need to make all parameters indexed
file: contracts/its/interfaces/IDistributable.sol 8 event DistributorChanged(address distributor);
file: contracts/its/interfaces/IFlowLimit.sol 8 event FlowLimitSet(uint256 flowLimit);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/interfaces/IFlowLimit.sol#L8
file: contracts/its/interfaces/IOperatable.sol 8 event OperatorChanged(address operator);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/interfaces/IOperatable.sol#L8
file: contracts/its/interfaces/IPausable.sol 11 event PausedSet(bool paused);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/interfaces/IPausable.sol#L11
file: contracts/its/interfaces/IRemoteAddressValidator.sol 14 event TrustedAddressAdded(string souceChain, string sourceAddress); 15 event TrustedAddressRemoved(string souceChain); 16 event GatewaySupportedChainAdded(string chain); 17 event GatewaySupportedChainRemoved(string chain);
type(uint120).max or type(uint112).max, etc. it uses more gas in the distribution process and also for each transaction than constant usage.
file: contracts/cgp/governance/AxelarServiceGovernance.sol 79 if (commandId > uint256(type(ServiceGovernanceCommand).max))
file: 120 if (commandId > uint256(type(GovernanceCommand).max))
file: contracts/its/interchain-token/InterchainToken.sol 56 if (allowance_ != type(uint256).max) { 57 if (allowance_ > type(uint256).max - amount) { 58 allowance_ = type(uint256).max - amount; 88 if (_allowance != type(uint256).max) 95 if (allowance_ != type(uint256).max) { 96 if (allowance_ > type(uint256).max - amount) { 97 allowance_ = type(uint256).max - amount;
file: contracts/its/interchain-token-service/InterchainTokenService.sol 104 if (tokenManagerImplementations.length != uint256(type(TokenManagerType).max) + 1) revert LengthMismatch();
// Booleans are more expensive than uint256 or any type that takes up a full // word because each write operation emits an extra SLOAD to first read the // slot's contents, replace the bits taken up by the boolean, and then write // back. This is the compiler's defense against contract upgrades and // pointer aliasing, and it cannot be disabled.
file: contracts/cgp/auth/MultisigBase.sol 15 mapping(address => bool) hasVoted; 21 mapping(address => bool) isSigner;
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L15
file: contracts/cgp/governance/AxelarServiceGovernance.sol 22 mapping(bytes32 => bool) public multisigApprovals;
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 24 mapping(string => mapping(address => bool)) public whitelistedCallers; 27 mapping(string => mapping(address => bool)) public whitelistedSenders;
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 19 mapping(string => bool) public supportedByGateway;
Before transfer, we should check for amount being 0 so the function doesnt run when its not gonna do anything:
file: contracts/cgp/AxelarGateway.sol 524 IERC20(tokenAddress).safeTransfer(account, amount);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L524
file: contracts/its/interchain-token/InterchainToken.sol 66 tokenManager.transmitInterchainTransfer{ value: msg.value }(sender, destinationChain, recipient, amount, metadata); 104 tokenManager.transmitInterchainTransfer{ value: msg.value }(sender, destinationChain, recipient, amount, metadata);
file: contracts/its/interchain-token-service/InterchainTokenService.sol 451 SafeTokenTransferFrom.safeTransferFrom(token, caller, destinationAddress, amount); 482 SafeTokenTransferFrom.safeTransferFrom(token, caller, destinationAddress, amount);
file: contracts/its/token-manager/implementations/TokenManagerLiquidityPool.sol 82 SafeTokenTransferFrom.safeTransferFrom(token, from, liquidityPool_, amount); 98 SafeTokenTransferFrom.safeTransferFrom(token, liquidityPool(), to, amount);
file: contracts/its/token-manager/implementations/TokenManagerLockUnlock.sol 48 SafeTokenTransferFrom.safeTransferFrom(token, from, address(this), amount); 64 SafeTokenTransfer.safeTransfer(token, to, amount);
Uninitialized variables are assigned with the types default value. Explicitly initializing a variable with it’s default value costs unnecesary gas.
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 74 for (uint256 i = 0; i < calls.length; i++)
file: contracts/interchain-governance-executor/InterchainProposalSender.sol 63 for (uint256 i = 0; i < interchainCalls.length; ) 106 for (uint256 i = 0; i < interchainCalls.length; )
file: contracts/its/utils/Multicall.sol 24 for (uint256 i = 0; i < data.length; ++i)
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Multicall.sol#L24
use abi.encodePacked() where possible to save gas
file: contracts/its/interchain-token-service/InterchainTokenService.sol 203 tokenId = keccak256(abi.encode(PREFIX_STANDARDIZED_TOKEN_ID, chainNameHash, tokenAddress)); 214 tokenId = keccak256(abi.encode(PREFIX_CUSTOM_TOKEN_ID, sender, salt)); 242 params = abi.encode(operator, tokenAddress); 252 params = abi.encode(operator, tokenAddress); 267 params = abi.encode(operator, tokenAddress, liquidityPoolAddress); 313 _deployTokenManager(tokenId, TokenManagerType.LOCK_UNLOCK, abi.encode(address(this).toBytes(), tokenAddress)); 401 _deployTokenManager(tokenId, tokenManagerType, abi.encode(msg.sender.toBytes(), tokenAddress)); 512 payload = abi.encode(SELECTOR_SEND_TOKEN, tokenId, destinationAddress, amount); 520 payload = abi.encode(SELECTOR_SEND_TOKEN_WITH_DATA, tokenId, destinationAddress, amount, sourceAddress.toBytes(), metadata); 696 abi.encode(operatorBytes.length == 0 ? address(this).toBytes() : operatorBytes, tokenAddress) 755 bytes memory payload = abi.encode(SELECTOR_DEPLOY_TOKEN_MANAGER, tokenId, tokenManagerType, params); 780 bytes memory payload = abi.encode( 828 return keccak256(abi.encode(PREFIX_STANDARDIZED_TOKEN_SALT, tokenId));
file: contracts/its/utils/ExpressCallHandler.sol 32 slot = uint256(keccak256(abi.encode(PREFIX_EXPRESS_RECEIVE_TOKEN, tokenId, destinationAddress, amount, commandId))) 57 abi.encode(
file: contracts/its/utils/FlowLimit.sol 47 slot = uint256(keccak256(abi.encode(PREFIX_FLOW_OUT_AMOUNT, epoch))); 56 slot = uint256(keccak256(abi.encode(PREFIX_FLOW_IN_AMOUNT, epoch)));
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/FlowLimit.sol#L47
file: contracts/its/utils/StandardizedTokenDeployer.sol 62 bytes memory params = abi.encode(tokenManager, distributor, name, symbol, decimals, mintAmount, mintTo); 63 bytecode = abi.encodePacked(type(StandardizedTokenProxy).creationCode, abi.encode(implementationAddress, params));
file: contracts/its/utils/TokenManagerDeployer.sol 38 bytes memory args = abi.encode(address(this), implementationType, tokenId, params);
file: contracts/cgp/AxelarGateway.sol 562 return keccak256(abi.encode(PREFIX_TOKEN_MINT_AMOUNT, symbol, day)); 584 return keccak256(abi.encode(PREFIX_CONTRACT_CALL_APPROVED, commandId, sourceChain, sourceAddress, contractAddress, payloadHash)); 597 keccak256( abi.encode( PREFIX_CONTRACT_CALL_APPROVED_WITH_MINT, commandId, sourceChain, sourceAddress, contractAddress, payloadHash, symbol, amount ) );
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L562
file: contracts/gmp-sdk/deploy/ConstAddressDeployer.sol 25 deployedAddress_ = _deploy(bytecode, keccak256(abi.encode(msg.sender, salt))); 47 deployedAddress_ = _deploy(bytecode, keccak256(abi.encode(msg.sender, salt))); 63 bytes32 newSalt = keccak256(abi.encode(sender, salt));
file: contracts/gmp-sdk/deploy/Create3Deployer.sol 30 bytes32 deploySalt = keccak256(abi.encode(msg.sender, salt)); 54 bytes32 deploySalt = keccak256(abi.encode(msg.sender, salt)); 68 bytes32 deploySalt = keccak256(abi.encode(sender, salt));
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 66 emit ProposalExecuted(keccak256(abi.encode(sourceChain, sourceAddress, interchainProposalCaller, payload)));
file: contracts/interchain-governance-executor/InterchainProposalSender.sol 89 bytes memory payload = abi.encode(msg.sender, interchainCall.calls);
Instead of using address(this), it is more gas-efficient to pre-calculate and use the hardcoded address. Foundry’s script.sol and solmate’s LibRlp.sol contracts can help achieve this. In Solidity, the address(this) expression returns the address of the current contract instance. This expression is commonly used to send or receive Ether to or from the contract.
The statement "Use hardcoded address instead of address(this) to save gas cost" means that using a hardcoded address instead of the address(this) expression can be more gas-efficient when sending or receiving Ether to or from the contract. This is because using the address(this) expression requires additional gas to be consumed to retrieve the address of the current contract, while using a hardcoded address does not.
For example, consider the following code:
contract MyContract { address public myAddress = 0x1234567890123456789012345678901234567890; function receiveEther() public payable { // Receive Ether using address(this) // msg.value is the value of the Ether being sent address(this).transfer(msg.value); } function receiveEtherHardcoded() public payable { // Receive Ether using hardcoded address // msg.value is the value of the Ether being sent myAddress.transfer(msg.value); } }
In this code, the receiveEther() function receives Ether using address(this), while the receiveEtherHardcoded() function receives Ether using a hardcoded address. Although both functions achieve the same result, the receiveEtherHardcoded() function is more gas-efficient, as it does not require additional gas to retrieve the address of the current contract.
Therefore, using a hardcoded address instead of the address(this) expression can be a gas-efficient way to send or receive Ether to or from a smart contract, as it reduces the gas cost of the contract. However, it is important to ensure that the hardcoded address is correct and does not change during the contract's lifetime.
file: contracts/gmp-sdk/upgradable/Upgradable.sol 23 implementationAddress = address(this); 31 if (address(this) == implementationAddress) revert NotProxy();
file: contracts/cgp/util/Caller.sol 16 if (nativeValue > address(this).balance) revert InsufficientBalance();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/util/Caller.sol#L16
file: contracts/gmp-sdk/deploy/Create3.sol 52 deployed = deployedAddress(address(this), salt);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/deploy/Create3.sol#L52
file: contracts/gmp-sdk/deploy/Create3Deployer.sol 69 return Create3.deployedAddress(address(this), deploySalt);
file: contracts/cgp/AxelarGateway.sol 73 if (msg.sender != address(this)) revert NotSelf(); 374 (bool success, ) = address(this).call(abi.encodeWithSelector(commandSelector, params[i], commandId)); 443 abi.encodeWithSelector(IERC20.transfer.selector, address(this), IERC20(tokenAddress).balanceOf(address(depositHandler))) 449 depositHandler.destroy(address(this)); 543 IERC20(tokenAddress).safeTransferFrom(sender, address(this), amount); 616 return address(uint160(uint256(keccak256(abi.encodePacked(bytes1(0xff), address(this), salt, codeHash)))));
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L73
file: contracts/gmp-sdk/upgradable/FinalProxy.sol 61 implementation_ = Create3.deployedAddress(address(this), FINAL_IMPLEMENTATION_SALT);
file: contracts/its/interchain-token-service/InterchainTokenService.sol 162 tokenManagerAddress = deployer.deployedAddress(address(this), tokenId); 193 tokenAddress = deployer.deployedAddress(address(this), tokenId); 313 _deployTokenManager(tokenId, TokenManagerType.LOCK_UNLOCK, abi.encode(address(this).toBytes(), tokenAddress)); 696 abi.encode(operatorBytes.length == 0 ? address(this).toBytes() : operatorBytes, tokenAddress) 716 address(this),
file: contracts/its/token-manager/TokenManager.sol 205 tokenId = ITokenManagerProxy(address(this)).tokenId();
file: contracts/its/token-manager/implementations/TokenManagerLockUnlock.sol 46 uint256 balance = token.balanceOf(address(this)); 48 SafeTokenTransferFrom.safeTransferFrom(token, from, address(this), amount); 51 return IERC20(token).balanceOf(address(this)) - balance;
file: contracts/its/utils/Implementation.sol 19 implementationAddress = address(this); 27 if (implementationAddress == address(this)) revert NotProxy();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Implementation.sol#L19
file: contracts/its/utils/Multicall.sol 25 (bool success, bytes memory result) = address(this).delegatecall(data[i]);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Multicall.sol#L25
file: contracts/its/utils/TokenManagerDeployer.sol 38 bytes memory args = abi.encode(address(this), implementationType, tokenId, params);
file: contracts/cgp/auth/MultisigBase.sol 142 function rotateSigners(address[] memory newAccounts, uint256 newThreshold) external virtual onlySigners
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L142
file: contracts/gmp-sdk/upgradable/Upgradable.sol 78 function setup(bytes calldata data) external override onlyProxy
file: contracts/its/interchain-token-service/InterchainTokenService.sol 502 function transmitSendToken( bytes32 tokenId, address sourceAddress, string calldata destinationChain, bytes memory destinationAddress, uint256 amount, bytes calldata metadata ) external payable onlyTokenManager(tokenId) notPaused 575 function _execute( string calldata sourceChain, string calldata sourceAddress, bytes calldata payload ) internal override onlyRemoteService(sourceChain, sourceAddress) notPaused
file: contracts/its/token-manager/TokenManager.sol 136 function transmitInterchainTransfer( address sender, string calldata destinationChain, bytes calldata destinationAddress, uint256 amount, bytes calldata metadata ) external payable virtual onlyToken 161 function giveToken(address destinationAddress, uint256 amount) external onlyService returns (uint256)
file: contracts/its/utils/Distributable.sol 51 function setDistributor(address distr) external onlyDistributor
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Distributable.sol#L51
file: 51 function setOperator(address operator_) external onlyOperator
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Operatable.sol#L51
Using assembly for loops can indeed help save gas in certain cases. Assembly is a low-level language that allows you to directly control the Ethereum Virtual Machine (EVM) operations, giving you fine-grained control over gas consumption. In some situations, using assembly loops can be more gas-efficient than using high-level loops like for or while loops.
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 44 for (uint256 i; i < length; ++i) { addTrustedAddress(trustedChainNames[i], trustedAddresses[i]); } 56 for (uint256 i; i < length; i++) { uint8 b = uint8(bytes(s)[i]); if ((b >= 65) && (b <= 70)) bytes(s)[i] = bytes1(b + uint8(32)); }
file: contracts/its/interchain-token-service/InterchainTokenService.sol 537 for (uint256 i; i < length; ++i) { ITokenManager tokenManager = ITokenManager(getValidTokenManagerAddress(tokenIds[i])); tokenManager.setFlowLimit(flowLimits[i]); }
file: contracts/interchain-governance-executor/InterchainProposalSender.sol 63 for (uint256 i = 0; i < interchainCalls.length; ) { _sendProposal(interchainCalls[i]); unchecked { ++i; } } 106 for (uint256 i = 0; i < interchainCalls.length; ) { totalGas += interchainCalls[i].gas; unchecked { ++i; } }
file: contracts/cgp/AxelarGateway.sol 270 for (uint256 i; i < length; ++i) { string memory symbol = symbols[i]; uint256 limit = limits[i]; if (tokenAddresses(symbol) == address(0)) revert TokenDoesNotExist(symbol); _setTokenMintLimit(symbol, limit); }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L270-L276
file: contracts/cgp/auth/MultisigBase.sol 70 for (uint256 i; i < count; ++i) { voting.hasVoted[signers.accounts[i]] = false; } 122 for (uint256 i; i < length; ++i) { if (votingPerTopic[signerEpoch][topic].hasVoted[signers.accounts[i]]) { voteCount++; } } 168 for (uint256 i; i < length; ++i) { address account = newAccounts[i]; // Check that the account wasn't already set as a signer for this epoch. if (signers.isSigner[account]) revert DuplicateSigner(account); if (account == address(0)) revert InvalidSigners(); signers.isSigner[account] = true; }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L70-L72
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 74 for (uint256 i = 0; i < calls.length; i++) { InterchainCalls.Call memory call = calls[i]; (bool success, bytes memory result) = call.target.call{ value: call.value }(call.callData); if (!success) { _onTargetExecutionFailed(call, result); } else { _onTargetExecuted(call, result); } }
Zero address control is not performed in the constructor in all 3 contracts within the scope of the audit. Bypassing this check could cause the contract to be deployed by mistakenly entering a zero address. In this case, the contract will need to be redeployed. This means extra gas consumption as contract deployment costs are high.
file: contracts/its/utils/Implementation.sol 18 constructor() { implementationAddress = address(this); }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/Implementation.sol#L18
file: 22 constructor(address deployer_) { if (deployer_ == address(0)) revert AddressZero(); deployer = Create3Deployer(deployer_); }
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 27 constructor(address _interchainTokenServiceAddress) { if (_interchainTokenServiceAddress == address(0)) revert ZeroAddress(); interchainTokenServiceAddress = _interchainTokenServiceAddress; interchainTokenServiceAddressHash = keccak256(bytes(_lowerCase(interchainTokenServiceAddress.toString()))); }
file: contracts/its/token-manager/TokenManager.sol 27 constructor(address interchainTokenService_) { if (interchainTokenService_ == address(0)) revert TokenLinkerZeroAddress(); interchainTokenService = IInterchainTokenService(interchainTokenService_); }
If a function modifier such as onlyOwner is used, the function will revert if a normal user tries to pay the function. Marking the function as payable will lower the gas cost for legitimate callers because the compiler will not include checks for whether a payment was provided.
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 83 function addTrustedAddress(string memory chain, string memory addr) public onlyOwner 95 function removeTrustedAddress(string calldata chain) external onlyOwner 106 function addGatewaySupportedChains(string[] calldata chainNames) external onlyOwner 119 function removeGatewaySupportedChains(string[] calldata chainNames) external onlyOwner
file: 92 function setWhitelistedProposalCaller( string calldata sourceChain, address sourceCaller, bool whitelisted ) external override onlyOwner 107 function setWhitelistedProposalSender( string calldata sourceChain, address sourceSender, bool whitelisted ) external override onlyOwner
fiel: 24 function transferOwnership(address newOwner) external virtual onlyOwner 40 function upgrade( address newImplementation, bytes32 newImplementationCodeHash, bytes calldata params ) external override onlyOwner
file: contracts/cgp/AxelarGateway.sol 421 function mintToken(bytes calldata params, bytes32) external onlySelf 427 function burnToken(bytes calldata params, bytes32) external onlySelf 455 function approveContractCall(bytes calldata params, bytes32 commandId) external onlySelf 469 function approveContractCallWithMint(bytes calldata params, bytes32 commandId) external onlySelf 495 function transferOperatorship(bytes calldata newOperatorsData, bytes32) external onlySelf
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L421
file: contracts/gmp-sdk/upgradable/Upgradable.sol 52 function upgrade( address newImplementation, bytes32 newImplementationCodeHash, bytes calldata params ) external override onlyOwner
When we say "use assembly for math operations," we mean that when performing basic math operations in a smart contract, it's more gas-efficient to use assembly code to perform the operation instead of Solidity's built-in math functions. This is because Solidity's built-in math functions require additional gas consumption to perform the operation.
file: contracts/cgp/auth/MultisigBase.sol 56 uint256 voteCount = voting.voteCount + 1;
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L56
file: contracts/gmp-sdk/util/TimeLock.sol 54 uint256 minimumEta = block.timestamp + _minimumTimeLockDelay;
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/util/TimeLock.sol#L54
file: contracts/its/interchain-token/InterchainToken.sol 61 _approve(sender, address(tokenManager), allowance_ + amount); 100 _approve(sender, address(tokenManager), allowance_ + amount);
When we say "use assembly to get a contract's balance of Ether," we mean that when retrieving the balance of Ether held by a contract, it's more gas-efficient to use assembly code to perform the operation instead of Solidity's built-in address.balance property. This is because Solidity's built-in address.balance property requires additional gas consumption to perform the operation.
file: contracts/cgp/util/Caller.sol 16 if (nativeValue > address(this).balance) revert InsufficientBalance();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/util/Caller.sol#L16
file: contracts/cgp/AxelarGateway.sol 332 bytes32[] memory commandIds; 333 string[] memory commands; 334 bytes[] memory params;
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L332
file: contracts/cgp/auth/MultisigBase.sol 19 address[] accounts;
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L19
file: contracts/interchain-governance-executor/lib/InterchainCalls.sol 17 Call[] calls;
If a similar external call is performed back-to-back, we can use assembly to reuse any function signatures and function parameters that stay the same. In addition, we can also reuse the same memory space for each function call (scratch space + free memory pointer + zero slot), which can potentially allow us to avoid memory expansion costs.
Note: In order to do this optimization safely we will cache the free memory pointer value and restore it once we are done with our function calls. We will also set the zero slot back to 0 if neccessary.
file: contracts/its/interchain-token-service/InterchainTokenService.sol 226 if (TokenManagerType(tokenManagerType) == TokenManagerType.LOCK_UNLOCK) { return implementationLockUnlock; } else if (TokenManagerType(tokenManagerType) == TokenManagerType.MINT_BURN) { return implementationMintBurn; } else if (TokenManagerType(tokenManagerType) == TokenManagerType.LIQUIDITY_POOL)
file: contracts/its/interchain-token-service/InterchainTokenService.sol 398 address tokenManagerAddress = getTokenManagerAddress(tokenId); TokenManagerType tokenManagerType = distributor == tokenManagerAddress ? TokenManagerType.MINT_BURN : TokenManagerType.LOCK_UNLOCK; address tokenAddress = getStandardizedTokenAddress(tokenId);
file: contracts/cgp/AxelarGateway.sol 505 function _hasCode(address addr) internal view returns (bool) { bytes32 codehash = addr.codehash; // https://eips.ethereum.org/EIPS/eip-1052 return codehash != bytes32(0) && codehash != 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470; } 619 function _getTokenType(string memory symbol) internal view returns (TokenType) { return TokenType(getUint(_getTokenTypeKey(symbol))); }
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L505-L530
file: contracts/its/token-manager/TokenManager.sol 204 function _getTokenId() internal view returns (bytes32 tokenId) { tokenId = ITokenManagerProxy(address(this)).tokenId(); }
Using custom errors rather than revert() or require() strings can indeed save gas in Solidity smart contracts. When you use revert() or require() with string messages, the entire string message is stored in the transaction's revert message, which consumes unnecessary gas. Enable the Solidity Compiler Optimizer The Solidity compiler optimizer works to simplify complex expressions, reducing code size and execution costs through inline operations, deployment costs, and function call costs.
The Solidity optimizer is best suited for inline operations. Even though inlining functions can result in significantly larger code, it is commonly used because it allows for additional simplifications.
The compiler optimizer also impacts the deployment and function call costs of your smart contracts.
For example, deployment costs decrease as the number of “runs” decreases—the frequency with which each opcode is executed over the course of a contract. The impact on function call costs, on the other hand, grows with the number of runs. This is because code optimized for more runs costs more to deploy and Custom errors, on the other hand, use predefined error codes (usually enum) to represent specific error conditions. These error codes are stored more efficiently in the transaction's revert message, resulting in reduced gas consumption.
Let's see an example to illustrate this gas-saving technique:
// Using custom errors contract CustomErrorsExample { error InvalidSetMintLimitsParams(); error TokenDoesNotExist(string symbol); function setTokenMintLimits(string[] calldata symbols, uint256[] calldata limits) external { uint256 length = symbols.length; if (length != limits.length) revert InvalidSetMintLimitsParams(); for (uint256 i = 0; i < length; ++i) { string memory symbol = symbols[i]; uint256 limit = limits[i]; if (tokenAddresses(symbol) == address(0)) revert TokenDoesNotExist(symbol); _setTokenMintLimit(symbol, limit); } } // Other contract functions... }
file: contracts/cgp/AxelarGateway.sol 65 if (authModule_.code.length == 0) revert InvalidAuthModule(); 66 if (tokenDeployerImplementation_.code.length == 0) revert InvalidTokenDeployer(); 73 if (msg.sender != address(this)) revert NotSelf(); 79 if (msg.sender != getAddress(KEY_GOVERNANCE)) revert NotGovernance(); 255 if (newGovernance == address(0)) revert InvalidGovernance(); 261 if (newMintLimiter == address(0)) revert InvalidMintLimiter(); 268 if (length != limits.length) revert InvalidSetMintLimitsParams(); 274 if (tokenAddresses(symbol) == address(0)) revert TokenDoesNotExist(symbol); 285 if (newImplementationCodeHash != newImplementation.codehash) revert InvalidCodeHash(); 296 if (!success) revert SetupFailed(); 309 if (implementation() == address(0)) revert NotProxy(); 338 if (chainId != block.chainid) revert InvalidChainId(); 342 if (commandsLength != commands.length || commandsLength != params.length) revert InvalidCommands(); 392 if (tokenAddresses(symbol) != address(0)) revert TokenAlreadyExists(symbol); 402 if (!success) revert TokenDeployFailed(symbol); 409 if (tokenAddress.code.length == uint256(0)) revert TokenContractDoesNotExist(tokenAddress); 432 if (tokenAddress == address(0)) revert TokenDoesNotExist(symbol); 446 if (!success || (returnData.length != uint256(0) && !abi.decode(returnData, (bool)))) revert BurnFailed(symbol); 519 if (tokenAddress == address(0)) revert TokenDoesNotExist(symbol); 537 if (tokenAddress == address(0)) revert TokenDoesNotExist(symbol); 538 if (amount == 0) revert InvalidAmount(); 635 if (limit > 0 && amount > limit) revert ExceedMintLimit(symbol);
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L65
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/AxelarGateway.sol#L635
file: contracts/cgp/auth/MultisigBase.sol 45 if (!signers.isSigner[msg.sender]) revert NotSigner(); 51 if (voting.hasVoted[msg.sender]) revert AlreadyVoted(); 159 if (newThreshold > length) revert InvalidSigners(); 161 if (newThreshold == 0) revert InvalidSignerThreshold(); 172 if (signers.isSigner[account]) revert DuplicateSigner(account); 173 if (account == address(0)) revert InvalidSigners();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/auth/MultisigBase.sol#L45
file: contracts/cgp/governance/AxelarServiceGovernance.sol 55 if (!multisigApprovals[proposalHash]) revert NotApproved(); 80 revert InvalidCommand();
file: contracts/cgp/governance/InterchainGovernance.sol 93 revert NotGovernance(); 100 if (target == address(0)) revert InvalidTarget(); 121 revert InvalidCommand(); 162 revert TokenNotSupported();
file: contracts/cgp/util/Caller.sol 16 if (nativeValue > address(this).balance) revert InsufficientBalance(); 20 revert ExecutionFailed();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/cgp/util/Caller.sol#L16
file: contracts/gmp-sdk/upgradable/Upgradable.sol 14 if (owner() != msg.sender) revert NotOwner(); 25 if (newOwner == address(0)) revert InvalidOwner(); 46 if (newImplementationCodeHash != newImplementation.codehash) revert InvalidCodeHash(); 51 if (!success) revert SetupFailed(); 63 if (implementation() == address(0)) revert NotProxy();
file: contracts/gmp-sdk/deploy/ConstAddressDeployer.sol 51 if (!success) revert FailedInit(); 81 if (bytecode.length == 0) revert EmptyBytecode(); 88 if (deployedAddress_ == address(0)) revert FailedDeploy();
file: contracts/gmp-sdk/deploy/Create3.sol 54 if (deployed.isContract()) revert AlreadyDeployed(); 55 if (bytecode.length == 0) revert EmptyBytecode(); 60 if (address(deployer) == address(0)) revert DeployFailed();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/deploy/Create3.sol#L54
file: contracts/gmp-sdk/deploy/Create3Deployer.sol 58 if (!success) revert FailedInit();
file: contracts/gmp-sdk/upgradable/FinalProxy.sol 77 if (msg.sender != owner) revert NotOwner(); 82 if (!success) revert SetupFailed();
file: contracts/gmp-sdk/upgradable/InitProxy.sol 46 if (msg.sender != owner) revert NotOwner(); 47 if (implementation() != address(0)) revert AlreadyInitialized(); 50 if (id != bytes32(0) && IUpgradable(implementationAddress).contractId() != id) revert InvalidImplementation(); 59 if (!success) revert SetupFailed();
file: contracts/gmp-sdk/upgradable/Proxy.sol 30 if (owner == address(0)) revert InvalidOwner(); 33 if (id != bytes32(0) && IUpgradable(implementationAddress).contractId() != id) revert InvalidImplementation(); 42 if (!success) revert SetupFailed();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/upgradable/Proxy.sol#L30
file: contracts/gmp-sdk/upgradable/Upgradable.sol 31 if (address(this) == implementationAddress) revert NotProxy(); 57 if (IUpgradable(newImplementation).contractId() != IUpgradable(this).contractId()) revert InvalidImplementation(); 58 if (newImplementationCodeHash != newImplementation.codehash) revert InvalidCodeHash(); 63 if (!success) revert SetupFailed();
file: contracts/gmp-sdk/util/TimeLock.sol 51 if (hash == 0) revert InvalidTimeLockHash(); 52 if (_getTimeLockEta(hash) != 0) revert TimeLockAlreadyScheduled(); 68 if (hash == 0) revert InvalidTimeLockHash(); 82 if (hash == 0 || eta == 0) revert InvalidTimeLockHash(); 84 if (block.timestamp < eta) revert TimeLockNotReady();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/gmp-sdk/util/TimeLock.sol#L51
file: contracts/interchain-governance-executor/InterchainProposalExecutor.sol 50 revert NotWhitelistedSourceAddress(); 58 revert NotWhitelistedCaller(); 164 revert(add(32, result), mload(result)) 168 revert ProposalExecuteFailed();
file: 97 revert ZeroAddress(); 104 revert LengthMismatch(); 124 revert NotRemoteService(); 133 revert NotTokenManager(); 172 revert TokenManagerDoesNotExist(tokenId); 311 if (gateway.tokenAddresses(tokenSymbol) == tokenAddress) revert GatewayToken(); 332 if (getCanonicalTokenId(tokenAddress) != tokenId) revert NotCanonicalTokenManager(); 445 if (gateway.isCommandExecuted(commandId)) revert AlreadyExecuted(commandId); 476 if (gateway.isCommandExecuted(commandId)) revert AlreadyExecuted(commandId); 519 if (version > 0) revert InvalidMetadataVersion(version); 536 if (length != flowLimits.length) revert LengthMismatch(); 565 if (implementation == address(0)) revert ZeroAddress(); 566 if (ITokenManager(implementation).implementationType() != uint256(tokenManagerType)) revert InvalidTokenManagerImplementation(); 590 revert SelectorUnknown(); 817 revert TokenManagerDeploymentFailed(); 867 revert StandardizedTokenDeploymentFailed();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/interchain-token-service/InterchainTokenService.sol#L97 https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/interchain-token-service/InterchainTokenService.sol#L867
file: contracts/its/libraries/AddressBytesUtils.sol 18 if (bytesAddress.length != 20) revert InvalidBytesLength(bytesAddress);
file: contracts/its/proxies/StandardizedTokenProxy.sol 22 if (IStandardizedToken(implementationAddress).contractId() != CONTRACT_ID) revert InvalidImplementation(); 25 if (!success) revert SetupFailed();if (!success) revert SetupFailed();
file: contracts/its/remote-address-validator/RemoteAddressValidator.sol 28 if (_interchainTokenServiceAddress == address(0)) revert ZeroAddress(); 43 if (length != trustedAddresses.length) revert LengthMismatch(); 84 if (bytes(chain).length == 0) revert ZeroStringLength(); 85 if (bytes(addr).length == 0) revert ZeroStringLength(); 96 if (bytes(chain).length == 0) revert ZeroStringLength();
file: contracts/its/token-manager/TokenManager.sol 28 if (interchainTokenService_ == address(0)) revert TokenLinkerZeroAddress(); 36 if (msg.sender != address(interchainTokenService)) revert NotService(); 44 if (msg.sender != tokenAddress()) revert NotToken();
file: contracts/its/utils/ExpressCallHandler.sol 91 if (prevExpressCaller != address(0)) revert AlreadyExpressCalled(); 133 if (prevExpressCaller != address(0)) revert AlreadyExpressCalled();
file: 101 if (flowToAdd + flowAmount > flowToCompare + flowLimit) revert FlowLimitExceeded();
https://github.com/code-423n4/2023-07-axelar/tree/main/contracts/its/utils/FlowLimit.sol#L101
The Solidity compiler optimizer works to simplify complex expressions, reducing code size and execution costs through inline operations, deployment costs, and function call costs.
The Solidity optimizer is best suited for inline operations. Even though inlining functions can result in significantly larger code, it is commonly used because it allows for additional simplifications.
The compiler optimizer also impacts the deployment and function call costs of your smart contracts.
For example, deployment costs decrease as the number of “runs” decreases—the frequency with which each opcode is executed over the course of a contract. The impact on function call costs, on the other hand, grows with the number of runs. This is because code optimized for more runs costs more to deploy and
#0 - c4-judge
2023-09-04T19:37:40Z
berndartmueller marked the issue as grade-a