1. NFT::permit(...) [`msg.sender` == attacker]
    -> GnosisSafe::isValidSignature [`msg.sender` == NFT contract]
        -> GnosisSafe::FallbackHandler::isValidSignature [`msg.sender` == Gnosis safe]
            -> FallbackHandler::isValidSignature -> `OK`
    -> NFT::_approve(spender, tokenId)

2. NFT::transferFrom(rentalSafe, attacker, tokenId)
    function isValidSignature(
        bytes memory data,
        bytes memory signature
    ) public view override returns (bytes4) {
        // Check if this fallback is active for the protocol.
        if (!isActive) {
            revert Errors.FallbackPolicy_Deactivated();
        }

        // Get the original sender. This is the address that called the safe.
        address originalSender = _msgSender();

        // Determine if the original sender is a token that has been whitelisted.
        if (STORE.whitelistedAssets(originalSender)) {
            revert Errors.FallbackPolicy_UnauthorizedSender(originalSender);
        }

        // Caller should be a Safe.
        Safe safe = Safe(payable(msg.sender));

        // Convert the data into a safe-compatible hash.
        bytes32 messageHash = getMessageHashForSafe(safe, data);

        // Check if the signature was signed by an owner of the safe.
        if (signature.length == 0 && safe.signedMessages(messageHash) == 0) {
            revert Errors.FallbackPolicy_HashNotSigned(messageHash);
        } else {
            safe.checkSignatures(messageHash, data, signature);
        }

        return EIP1271_MAGIC_VALUE;
    }
        ........

        // Determine if the original sender is a token that has been whitelisted.
        if (STORE.whitelistedAssets(originalSender)) {
            revert Errors.FallbackPolicy_UnauthorizedSender(originalSender);
        }

        ........
