Submission Details
Severity:
If a token is USDC and a winner is added to the USDC blacklist, the distribute() will revert
Summary
Distributor._distribute sends prizes to all contest winners, but if a winner is added to USDC blacklist, the call will revert.
Vulnerability Details
When a contest ends, prizes are distributed to all winners in a single call. If the contest token is USDC and any of the winners is added to USDC blacklist, the distribution will revert and thus none of the winners will receive a prize.
function _distribute(address token, address[] memory winners, uint256[] memory percentages, bytes memory data)
internal
{
// token address input check
if (token == address(0)) revert Distributor__NoZeroAddress();
if (!_isWhiteListed(token)) {
revert Distributor__InvalidTokenAddress();
}
// winners and percentages input check
if (winners.length == 0 || winners.length != percentages.length) revert Distributor__MismatchedArrays();
uint256 percentagesLength = percentages.length;
uint256 totalPercentage;
for (uint256 i; i < percentagesLength;) {
totalPercentage += percentages[i];
unchecked {
++i;
}
}
// check if totalPercentage is correct
if (totalPercentage != (10000 - COMMISSION_FEE)) {
revert Distributor__MismatchedPercentages();
}
IERC20 erc20 = IERC20(token);
uint256 totalAmount = erc20.balanceOf(address(this));
// if there is no token to distribute, then revert
if (totalAmount == 0) revert Distributor__NoTokenToDistribute();
uint256 winnersLength = winners.length; // cache length
for (uint256 i; i < winnersLength;) {
uint256 amount = totalAmount * percentages[i] / BASIS_POINTS;
erc20.safeTransfer(winners[i], amount);
unchecked {
++i;
}
}
Impact
A winner, blacklisted by the USDC token may prevent all winners to receive their prizes from a contest.
Tools Used
Manual review
Recommendations
Implement Pull over Push pattern so each winner can claim their reward individually.
Prize pool breakdown
Total prize
15,000 USDC
nSLOC
19477 USDC / LOC
14,000 USDC
1,000 USDC
Live
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