Storage Lookup

contract Protocol {
    // This variable is stored in slot 0
    address owner;

    function setOwner(address owner_) public {
        owner = owner_;
    }
}

contract StorageLookupAssertion is Assertion {
    Protocol public protocol;

    constructor(Protocol protocol_) {
        protocol = protocol_;
    }

    function triggers() public view override {
        registerCallTrigger(this.assertionStorageLookup.selector);
    }

    function assertionStorageLookup() public {
        // Define a whitelist of allowed owner addresses
        address[] memory whitelist = new address[](2);
        whitelist[0] = address(0x1);
        whitelist[1] = address(0x2);

        // Read owner from storage slot 0
        // Complex casting is needed because load() returns bytes32
        // 1. Convert bytes32 to uint256
        // 2. Convert uint256 to uint160 (address size)
        // 3. Cast to address type
        address owner = address(uint160(uint256(ph.load(address(protocol), bytes32(uint256(0))))));

        // Verify the owner is in the whitelist
        for (uint256 i = 0; i < whitelist.length; i++) {
            if (owner == whitelist[i]) {
                return;
            }
        }

        revert("Owner not in whitelist");
    }
}