Sparkn

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Submission Details
Severity: low
Valid

Zero token transfer can cause a potential DoS in Distributor.sol

nadin

Summary

The Distributor.sol contract doesn't check for zero amount while transferring rewards, which can end up blocking the operation.

Vulnerability Details

  • In Distributor.sol contract, the function distribute() is used to distribute token to winners according to the percentages: here

function distribute(address token, address[] memory winners, uint256[] memory percentages, bytes memory data)
external
{
if (msg.sender != FACTORY_ADDRESS) {
revert Distributor__OnlyFactoryAddressIsAllowed();
}
_distribute(token, winners, percentages, data);
}

  • Then function _distribute() is called: here

116: function _distribute(address token, address[] memory winners, uint256[] memory percentages, bytes memory data)
117: internal
118: {
---SKIP---
144: uint256 winnersLength = winners.length; // cache length
145: for (uint256 i; i < winnersLength;) {
146: uint256 amount = totalAmount * percentages[i] / BASIS_POINTS;
147: erc20.safeTransfer(winners[i], amount);
148: unchecked {
149: ++i;
150: }
151: }
152:
153: // send commission fee as well as all the remaining tokens to STADIUM_ADDRESS to avoid dust remaining
154: _commissionTransfer(erc20);
155: emit Distributed(token, winners, percentages, data);
156: }

  • At L146-L147,amount after calculated will be transferred to winners[i] but doesn't check for zero amount before transferring.amount will returns 0 if totalAmount * percentages[i] < BASIS_POINTS.

  • This is a bit concerning as some ERC20 implementations revert on zero value transfers (see https://github.com/d-xo/weird-erc20#revert-on-zero-value-transfers).

  • So the current implementation may cause a denial of service, as a zero amount transfer in this token will block the whole action and revert the transaction.

Impact

The function Distributor.sol#distribute() doesn't check for zero amount while transferring rewards, which can end up blocking the operation.

Tools Used

Manual review

Recommendations

Check for zero amount before executing the transfer.
Eg:

+++ if (amount == 0) revert;

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