Submission Details
Severity:
`DebtToken.sol#totalSupply`: Incorrectly implementation for rebase token
Vulnerability Details
RToken.sol#totalSupply should use the same calculation method as RToken.sol#balanceOf.
/// @dev https://github.com/Cyfrin/2025-02-raac/blob/89ccb062e2b175374d40d824263a4c0b601bcb7f/contracts/core/tokens/DebtToken.sol#L223
function balanceOf(address account) public view override(ERC20, IERC20) returns (uint256) {
uint256 scaledBalance = super.balanceOf(account);
return scaledBalance.rayMul(ILendingPool(_reservePool).getNormalizedDebt());
}
/// @dev https://github.com/Cyfrin/2025-02-raac/blob/89ccb062e2b175374d40d824263a4c0b601bcb7f/contracts/core/tokens/DebtToken.sol#L232
function totalSupply() public view override(ERC20, IERC20) returns (uint256) {
uint256 scaledSupply = super.totalSupply();
return scaledSupply.rayDiv(ILendingPool(_reservePool).getNormalizedDebt());
}
Impact
It will break the invariant that sum of the balance for all accounts is equal to totalSupply.
Tools Used
Manual.
Recommendations
function totalSupply() public view override(ERC20, IERC20) returns (uint256) {
uint256 scaledSupply = super.totalSupply();
return scaledSupply.rayMul(ILendingPool(_reservePool).getNormalizedDebt());
}
Updates
Lead Judging Commences
inallhonesty 4 months ago
Submission Judgement Published Assigned finding tags:
DebtToken::totalSupply incorrectly uses rayDiv instead of rayMul, severely under-reporting total debt and causing lending protocol accounting errors
inallhonesty 4 months ago
Submission Judgement Published Assigned finding tags:
DebtToken::totalSupply incorrectly uses rayDiv instead of rayMul, severely under-reporting total debt and causing lending protocol accounting errors
Prize pool breakdown
Total prize
77,280 USDC
nSLOC
3,86420 USDC / LOC
74,000
3,280
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