incorrect operator used in buyOption() function

[code423n4]

Lines of code

https://github.com/code-423n4/2022-05-cally/blob/main/contracts/src/Cally.sol#L224

Vulnerability details

Impact

In Cally.sol the buyOption() function requires that the msg.value is greater than or equal to the premium when it should always be greater and not equal since the premium is the base fee to buy the option. The msg.value should naturally always be higher than the base fee when buying an option.

Proof of Concept

https://github.com/code-423n4/2022-05-cally/blob/main/contracts/src/Cally.sol#L224

Tools Used

Manual code review

Recommended Mitigation Steps

-    require(msg.value >= premium, "Incorrect ETH amount sent");
+    require(msg.value > premium, "Incorrect ETH amount sent");

[outdoteth]

It should be equal not greater

require(msg.value == premium);

Not sure if this qualifies as an issue because it gives the incorrect solution but does identify an issue

[outdoteth]

reference issue: #84

[HardlyDifficult]

Yes, we'll still consider this a valid submission -- the more important point is they identified an issue. Keeping this as a dupe