use of the delegatecall function in the allocate function

[code423n4]

Lines of code

https://github.com/code-423n4/2023-05-juicebox/blob/9a36e5c8d0588f0f262a0cd1c08e34b2184d8f4d/juice-buyback/contracts/mock/MockAllocator.sol#L36

Vulnerability details

Impact

The delegatecall function executes the called contract's code in the context of the calling contract, meaning that the called contract can access and modify the calling contract's storage and state variables. If the payDelegate contract is malicious or vulnerable to attacks, it could exploit this access to manipulate or steal funds from the MockAllocator contract.

Proof of Concept

you can consider replacing it with a regular call function invocation. The call function provides a more controlled way to interact with external contracts. Here's an example of how I modified the code to use call instead:

(bool success, ) = address(payDelegate).call(
    abi.encodeWithSignature("didPay(JBDidPayData)", _didPaydata)
);
require(success, "External call to payDelegate failed");

In my modified code, the call function is used to invoke the didPay function in the payDelegate contract. The success variable is used to capture the result of the external call, indicating whether it was executed successfully. The require statement ensures that the external call to payDelegate was successful. If the call fails, the transaction will be reverted, preventing the execution of any malicious or unintended code.

By using call instead of delegatecall, you can restrict the external contract's access to the storage and state variables of the MockAllocator contract. It provides a safer way to interact with external contracts, reducing the risk of unintended side effects or unauthorized modifications.

Tools Used

VSCode

Recommended Mitigation Steps

1. Limit the scope of delegatecall: If possible, avoid using delegatecall altogether. Evaluate if there are alternative ways to achieve the desired functionality without relying on delegatecall.
2. Consider using formal verification tools and techniques to mathematically prove the correctness and security of the payDelegate contract. Formal verification can help identify potential vulnerabilities and ensure that the contract behaves as intended.
3. Apply checks and safeguards: If delegatecall is necessary, ensure that appropriate checks and safeguards are in place. For example, you can implement checks to verify the validity and integrity of the payDelegate contract before making the delegatecall. Use require statements or other assertions to validate inputs and ensure the expected behavior of the payDelegate contract.

Assessed type

call/delegatecall

[c4-pre-sort]

dmvt marked the issue as low quality report

[dmvt]

out of scope

[c4-judge]

dmvt marked the issue as unsatisfactory: Out of scope