The Standard
The Standard
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Submission Details
Severity: medium
Invalid

Accounting Error Causes `mint()` Function to Revert

krisrenzo

Description:
When users deposit collateral to their vault, they can mint EUROs. The function maxMintable() returns the maximum amount of EUROs a vault is allowed to mint. When users call mint(), a sub-function call to fullyCollateralised() is made to check if the amount the user wants to mint can be supported by their collateral. However, instead of passing in the _amount to be minted in this fullyCollateralised(), the mint function passes the sum of the amount the user wants to mint and the fee (which is a percentage of the amount). This means that if a user attempts to mint the maxMintable of their vault, the call is reverted.

Impact:
This may be confusing for users, as the protocol contradicts itself.

Tools Used:

  • Manual review

Recommended Mitigation Steps:
Burn _amount - fee, then send the fee.

- function mint(address _to, uint256 _amount) external onlyOwner ifNotLiquidated {
- uint256 fee = _amount * ISmartVaultManagerV3(manager).mintFeeRate() / ISmartVaultManagerV3(manager).HUNDRED_PC();
- require(fullyCollateralised(_amount + fee), UNDER_COLL);
- minted = minted + _amount + fee;
- EUROs.mint(_to, _amount);
- EUROs.mint(ISmartVaultManagerV3(manager).protocol(), fee);
- emit EUROsMinted(_to, _amount, fee);
- }
​
// Correct implementation
​
+ function mint(address _to, uint256 _amount) external onlyOwner ifNotLiquidated {
+ uint256 fee = _amount * ISmartVaultManagerV3(manager).mintFeeRate() / ISmartVaultManagerV3(manager).HUNDRED_PC();
+ require(fullyCollateralised(_amount), UNDER_COLL);
+ minted = minted + _amount;
+ EUROs.mint(_to, _amount - fee);
+ EUROs.mint(ISmartVaultManagerV3(manager).liquidator(), fee);
+ emit EUROsMinted(_to, _amount - fee, fee);
+ }
Updates

Lead Judging Commences

hrishibhat Lead Judge almost 2 years ago
Submission Judgement Published
Validated
Assigned finding tags:

fee-loss

hrishibhat Lead Judge almost 2 years ago
Submission Judgement Published
Invalidated
Reason: Design choice
Assigned finding tags:

fee-loss

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