Core Contracts
Regnum Aurum Acquisition Corp
HardhatReal World AssetsNFT
77,280 USDC
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Submission Details
Severity: high
Valid

`RToken.transferFrom()` transfers incorrect amount

pabloperezacc6

Summary

The RToken.transferFrom() function calculates the amount to be trasfered incorrectly.

Vulnerability Details

The RToken.transferFrom() function calculates scaledAmount as amount / reserve.liquidityIndex.

function transferFrom(address sender, address recipient, uint256 amount) public override(ERC20, IERC20) returns (bool) {
@> uint256 scaledAmount = amount.rayDiv(_liquidityIndex);
return super.transferFrom(sender, recipient, scaledAmount);
}

Then, scaledAmount is scaled again in the _update() function. As result, the real transfered amount is amount / (reserve.liquidityIndex ^ 2) which is less than correct value.

function _update(address from, address to, uint256 amount) internal override {
// Scale amount by normalized income for all operations (mint, burn, transfer)
@> uint256 scaledAmount = amount.rayDiv(ILendingPool(_reservePool).getNormalizedIncome());
super._update(from, to, scaledAmount);
}

Impact

Users receive less tokens than real amount to be transfered.

Tools Used

Manual Review

Recommendations

Remove the process of scaling amount in transferFrom().

function transferFrom(address sender, address recipient, uint256 amount) public override(ERC20, IERC20) returns (bool) {
- uint256 scaledAmount = amount.rayDiv(_liquidityIndex);
return super.transferFrom(sender, recipient, scaledAmount);
}
Updates

Lead Judging Commences

inallhonesty Lead Judge 3 months ago
Submission Judgement Published
Validated
Assigned finding tags:

RToken::transfer and transferFrom double-scale amounts by dividing in both external functions and _update, causing users to transfer significantly less than intended

inallhonesty Lead Judge 3 months ago
Submission Judgement Published
Validated
Assigned finding tags:

RToken::transfer and transferFrom double-scale amounts by dividing in both external functions and _update, causing users to transfer significantly less than intended

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