Tadle

Summary

The createOffer() function in the PreMarktes contract contains a bug in the validation of the collateral rate.

Vulnerability Details

According to the CreateOfferParams struct comment, the collateralRate parameter "must be greater than 100%" with a decimal scaling factor of 10000.

https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/interfaces/IPerMarkets.sol#L292

However, the actual implementation in the createOffer() function incorrectly validates this condition:

https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/core/PreMarkets.sol#L53

The current implementation only checks if the collateralRate is less than the COLLATERAL_RATE_DECIMAL_SCALER (which is 10000, representing 100%). This allows a collateralRate of exactly 100% to pass the check, contradicting the requirement stated in the struct comment that it must be greater than 100%.

Impact

This bug could lead to the creation of offers with insufficient collateral. It may result in undercollateralized positions, increasing the risk of insolvency and potentially leading to financial losses for users or the protocol itself.

Tools Used

Manual review

Recommendations

Modify the condition to strictly enforce a collateral rate greater than 100%:

if (params.collateralRate <= Constants.COLLATERAL_RATE_DECIMAL_SCALER) {
revert InvalidCollateralRate();
}