Sablier
Sablier
DeFiFoundry
53,440 USDC
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Submission Details
Severity: high
Invalid

`Helpers::checkAndCalculateBrokerFee` return zero broker fee for tokens with < 18 decimals.

alymurtazamemon

Summary

The prb library doesn't calculate correct broker fee for tokens with < 18 decimals.

Vulnerability details

The protocol uses the MAX_BROKER_FEE constant to limit brokers to charging only up to 10% of the total amount as a broker fee when creating streams. However, its value is hardcoded with 18 decimals. Because of this, the Helpers::checkAndCalculateBrokerFee function returns zero broker fee for tokens with < 18 decimals.

Impact

Brokers will get 0 fee for tokens with < 18 decimals.

Proof of Concept

Put this code in any file and run it using command bun run test --mt test_checkAndCalculateBrokerFee -vvv.

// SPDX-License-Identifier: MIT
​
pragma solidity >=0.8.22;
​
import { Test } from "forge-std/src/Test.sol";
import { console } from "forge-std/src/console.sol";
​
import { Helpers } from "src/libraries/Helpers.sol";
import { UD60x18 } from "@prb/math/src/UD60x18.sol";
import { Lockup } from "src/types/DataTypes.sol";
​
contract HelperTest is Test {
UD60x18 public constant MAX_BROKER_FEE = UD60x18.wrap(0.1e18);
​
function setUp() external { }
​
function test_checkAndCalculateBrokerFee() external {
// tokens with less than 18 decimals
uint128 totalAmount = 100e6; // 100 USDC - USDC has 6 decimals
uint128 brokerFee = 0.1e6; // 10% fee which should thow
​
Lockup.CreateAmounts memory createAmounts =
Helpers.checkAndCalculateBrokerFee(totalAmount, UD60x18.wrap(brokerFee), MAX_BROKER_FEE);
​
console.log(createAmounts.brokerFee);
console.log(createAmounts.deposit);
​
assertEq(createAmounts.brokerFee, 0);
assertEq(createAmounts.deposit, 100e6);
}
}

Tools Used

Manual Review, Foundry

Recommended Mitigation Steps

Make sure the prb library performs correct calculations for tokens with < 18 decimals.

Updates

Lead Judging Commences

inallhonesty Lead Judge
over 1 year ago
inallhonesty Lead Judge over 1 year ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement

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