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Submission Details
Severity: high
Valid

Incorrect calculation of collateral amount in the `PreMarkets.listOffer` function.

kupiasec

Github link

https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/core/PreMarkets.sol#L349

Summary

The PreMarkets.listOffer function incorrectly calculates transferAmount using offerInfo.collateralRate instead of using _collateralRate.

Vulnerability Details

When offer settle type is protected, stockInfo.authority deposits collateral from L356.

https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/core/PreMarkets.sol#L295-L396

if (makerInfo.offerSettleType == OfferSettleType.Protected) {
uint256 transferAmount = OfferLibraries.getDepositAmount(
offerInfo.offerType,
L349: offerInfo.collateralRate,
_amount,
true,
Math.Rounding.Ceil
);
​
ITokenManager tokenManager = tadleFactory.getTokenManager();
L356: tokenManager.tillIn{value: msg.value}(
_msgSender(),
makerInfo.tokenAddress,
transferAmount,
false
);
}

The PreMarkets.listOffer function has _collateralRate argument and collateralRate of the new ask offer is setted as this argument.
This means that stockInfo.authority should deposit amount of collateral calculated using _collateralRate.
But, from L349, the amount of collateral is calculated incorrectly using offerInfo.collateralRate, instead of _collateralRate .

Impact

In protected mode, deposited amount of collateral of listed offer and information stored in the offerInfoMap variable of the listed offer are different.
The protocol introduces protected mode to enhance buyer assurance and reduce default risks.
But, this is broken by the difference.

Tools Used

Manual Review

Recommendations

It is recommended to change the code as following:

https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/core/PreMarkets.sol#L349

if (makerInfo.offerSettleType == OfferSettleType.Protected) {
uint256 transferAmount = OfferLibraries.getDepositAmount(
offerInfo.offerType,
- offerInfo.collateralRate,
+ _collateralRate,
_amount,
true,
Math.Rounding.Ceil
);
​
ITokenManager tokenManager = tadleFactory.getTokenManager();
tokenManager.tillIn{value: msg.value}(
_msgSender(),
makerInfo.tokenAddress,
transferAmount,
false
);
}
Updates

Lead Judging Commences

0xnevi Lead Judge 10 months ago
Submission Judgement Published
Validated
Assigned finding tags:

finding-PreMarkets-listOffer-collateralRate-manipulate

Valid high severity, because the collateral rate utilized when creating an offer is stale and retrieved from a previously set collateral rate, it allows possible manipilation of refund amounts using an inflated collateral rate to drain funds from the CapitalPool contract

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