26286 - [SC - Insight] Potential Signature Validation Bypass

Submitted on Nov 30th 2023 at 09:33:15 UTC by @EricTee for Boost | DeGate

Report ID: #26286

Report type: Smart Contract

Report severity: Insight

Target: https://github.com/degatedev/protocols/blob/degate_mainnet/packages/loopring_v3/contracts/lib/SignatureUtil.sol#L32-L51

Impacts:

• Signature Validation Bypass

Description

Bug Description

In https://github.com/degatedev/protocols/blob/degate_mainnet/packages/loopring_v3/contracts/lib/SignatureUtil.sol#L32-L51:

    function verifySignatures(
        bytes32          signHash,
        address[] memory signers,
        bytes[]   memory signatures
        )
        internal
        view
        returns (bool)
    {
        require(signers.length == signatures.length, "BAD_SIGNATURE_DATA");
        address lastSigner;
        for (uint i = 0; i < signers.length; i++) {
            require(signers[i] > lastSigner, "INVALID_SIGNERS_ORDER");
            lastSigner = signers[i];
            if (!verifySignature(signHash, signers[i], signatures[i])) {
                return false;
            }
        }
        return true;
    }

There is a potential signature validation bypass scenario happens in the above code, since there is no check that require(signers.length != 0), if an attacker passes in empty array of signers and signatures values, he can bypass the for loop. As a result, the function will directly return true. Though this function is not used anyway in the protocol yet, but I think the awareness should be raised to the protocol team in case this function is implemented in the future.

Impact

Potential Signature Validation Bypass

Risk Breakdown

Difficulty to Exploit: Easy Weakness: Signature Validation Bypass CVSS2 Score: NA

Recommendation

Consider adding the check require(signers.length != 0, "BAD_SIGNATURE_DATA");:

    function verifySignatures(
        bytes32          signHash,
        address[] memory signers,
        bytes[]   memory signatures
        )
        internal
        view
        returns (bool)
    {
++      require(signers.length != 0, "BAD_SIGNATURE_DATA");
        require(signers.length == signatures.length, "BAD_SIGNATURE_DATA");
        address lastSigner;
        for (uint i = 0; i < signers.length; i++) {
            require(signers[i] > lastSigner, "INVALID_SIGNERS_ORDER");
            lastSigner = signers[i];
            if (!verifySignature(signHash, signers[i], signatures[i])) {
                return false;
            }
        }
        return true;
    }

References

NA

Proof of concept

NA