Submission Details
Severity:
abi.encodePacked() should not be used with dynamic types when passing the result to a hash function such as keccak256()
Summary
abi.encodePacked() should not be used with dynamic types when passing the result to a hash function such as keccak256()
Vulnerability Details
Use abi.encode() instead which will pad items to 32 bytes, which will prevent hash collisions (e.g. abi.encodePacked(0x123,0x456) => 0x123456 => abi.encodePacked(0x1,0x23456), but abi.encode(0x123,0x456) => 0x0...1230...456). "Unless there is a compelling reason, abi.encode should be preferred".
Impact
function getProxyAddress(bytes32 salt, address implementation) public view returns (address proxy) {
bytes memory code = abi.encodePacked(type(Proxy).creationCode, uint256(uint160(implementation)));
bytes32 hash = keccak256(abi.encodePacked(bytes1(0xff), address(this), salt, keccak256(code)));
proxy = address(uint160(uint256(hash)));
}
Recommendations
Use abi.encode()
Prize pool breakdown
Total prize
15,000 USDC
nSLOC
19477 USDC / LOC
14,000 USDC
1,000 USDC
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