Submission Details
Severity:
Missing Zero address check on `fixUser()` function
Summary
The functions fixUser(address liquidator, address user) that take address as an argument are not validating that the address is not 0.
Vulnerability Details
Vulnerability lies in below function
function fixUser(address liquidator, address user) external {
/// @dev check user is admin
require(msg.sender == admin, "only the admin may call fixUser");
/// ensure nothing strange can happen with incorrect liquidator
require(liquidator != user, "liquidator cannot be user");
require(accrueInterest() == 0, "accrue interest failed");
/// @dev fetch user's current borrow balance, first updating interest index
uint256 principal = borrowBalanceStored(user);
require(principal != 0, "cannot liquidate user without borrows");
/// user effects
/// @dev zero balance
accountBorrows[user].principal = 0;
accountBorrows[user].interestIndex = borrowIndex;
/// @dev current amount for a user that we'll transfer to the liquidator
uint256 liquidated = accountTokens[user];
/// can only seize collateral assets if they exist
if (liquidated != 0) {
/// if assets were liquidated, give them to the liquidator
accountTokens[liquidator] = SafeMath.add(
accountTokens[liquidator],
liquidated
);
/// zero out the user's tokens
delete accountTokens[user];
}
/// global effects
/// @dev increment the bad debt counter
badDebt = SafeMath.add(badDebt, principal);
/// @dev subtract the previous balance from the totalBorrows balance
totalBorrows = SafeMath.sub(totalBorrows, principal);
emit UserFixed(user, liquidator, liquidated);
}
Impact
Medium
Tools Used
Manual
Recommendations
+ require( liquidator != address(0),"Zero address not allowed");
+ require(user != address(0) , "Zero address not allowed");
Prize pool breakdown
Total prize
15,000 USDC
nSLOC
39438
USDC / LOC
14,000 USDC
1,000 USDC
1,500 USDC
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