First Flight #15: Mondrian Wallet
First Flight #15
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Submission Details
Severity: medium
Valid

[M-1] `MondrianWallet::_ValidateSignature` doesn't return `SIG_VALIDATION_FAILED` violating the `EIP-4337`

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Description

The EIP 4337 states that when even a Signature Validation is not successful the SIG_VALIDATION_FAILED should be returned and revert for any other errors, but the function MondrianWallet::_ValidateSignature doesn't return SIG_VALIDATION_FAILED which may lead to unexpected reverts as the contract is not in compliance with the EIP-4337

Impact

The entryPoint contract will be designed in compliance with the EIP-4337 and it expects a the return value when the signature validation fails to be SIG_VALIDATION_FAILEDwhich is set to 1 but here the call will be reverted leading to unexpected reverts

Proof of Concept

The function below only returns SIG_VALIDATION_SUCCESS

PoC
function _validateSignature(PackedUserOperation calldata userOp, bytes32 userOpHash)
internal
pure
returns (uint256 validationData)
{
bytes32 hash = MessageHashUtils.toEthSignedMessageHash(userOpHash);
ECDSA.recover(hash, userOp.signature);
@> return SIG_VALIDATION_SUCCESS;
}

There is no SIG_VALIDATION_FAILED variable used in MondrianWallet::_ValidateSignature even though it is imported into the contract

Recommended Mitigation

Please Refer to [H-1] for a more detailed mitigation as the issue expects the mitigation of [H-1] to already have been implemented.

If the Signature validation fails the contract should return SIG_VALIDATION_FAILED

make changes MondrianWallet::_ValidateSignature as given below :

function _validateSignature(PackedUserOperation calldata userOp, bytes32 userOpHash)
internal
pure
returns (uint256 validationData)
{
bytes32 hash = MessageHashUtils.toEthSignedMessageHash(userOpHash);
(owner()!= ECDSA.recover(hash, userOp.signature))
{
return SIG_VALIDATION_FAILED;
}
return SIG_VALIDATION_SUCCESS;
}
Updates

Lead Judging Commences

inallhonesty Lead Judge about 1 year ago
Submission Judgement Published
Validated
Assigned finding tags:

`_validateSignature` SHOULD return SIG_VALIDATION_FAILED (and not revert) on signature mismatch.

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