Closed code423n4 closed 2 years ago
Arbitrary ERC20 tokens can't be used. They have to be pre approved by the contract.
Low
Since tokens require approval, and this report does not make clear where things would break down due to a fee on transfer token - closing as invalid.
Lines of code
https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L239 https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L339 https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L729 https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L745 https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L793 https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L1144 https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/core/InfinityExchange.sol#L1146
Vulnerability details
As arbitrary ERC20 tokens can be passed, the amount here should be calculated every time to take into consideration a possible fee-on-transfer or deflation. Also, it's a good practice for the future of the solution.
Affected code:
Recommended Mitigation Steps
Use the balance before and after the transfer to calculate the received amount instead of assuming that it would be equal to the amount passed as a parameter.
As a template: