Potential infinite loop

[c4-bot-7]

Lines of code

https://github.com/code-423n4/2023-12-ethereumcreditguild/blob/2376d9af792584e3d15ec9c32578daa33bb56b43/src/tokens/ERC20Gauges.sol#L532-L534

Vulnerability details

Impact

The loop contains a misplaced increment operation i++, which could lead to an infinite loop if userGaugeWeight is zero, as i would never be incremented.

Proof of Concept

The related code snippet is part of a loop that iterates over a list of gauges to calculate weights and perform certain updates. However, there is a potential issue with the position of the i++ increment operation within the loop. It is placed inside an unchecked block and within a conditional statement that checks if userGaugeWeight is not equal to zero. If userGaugeWeight is zero for any gauge, the increment will be skipped, potentially causing an infinite loop as the index i will not be updated.

        for (
            uint256 i = 0;
            i < size && (userFreeWeight + userFreed) < weight;

        ) {
            address gauge = gaugeList[i];
            uint256 userGaugeWeight = getUserGaugeWeight[user][gauge];
            if (userGaugeWeight != 0) {
                userFreed += userGaugeWeight;
                _decrementGaugeWeight(user, gauge, userGaugeWeight);

                // If the gauge is live (not deprecated), include its weight in the total to remove
                if (!_deprecatedGauges.contains(gauge)) {
                    totalTypeWeight[gaugeType[gauge]] -= userGaugeWeight;
                    totalFreed += userGaugeWeight;
                }

                unchecked {
                    ++i;
                }
            }
        }

Tools Used

Recommended Mitigation Steps

        for (
            uint256 i = 0;
            i < size && (userFreeWeight + userFreed) < weight;

        ) {
            address gauge = gaugeList[i];
            uint256 userGaugeWeight = getUserGaugeWeight[user][gauge];
            if (userGaugeWeight != 0) {
                userFreed += userGaugeWeight;
                _decrementGaugeWeight(user, gauge, userGaugeWeight);

                // If the gauge is live (not deprecated), include its weight in the total to remove
                if (!_deprecatedGauges.contains(gauge)) {
                    totalTypeWeight[gaugeType[gauge]] -= userGaugeWeight;
                    totalFreed += userGaugeWeight;
                }

-               unchecked {
-                   ++i;
-               }
            }
+           unchecked {
+               ++i;
+           }

        }

Assessed type

Loop

[c4-pre-sort]

0xSorryNotSorry marked the issue as sufficient quality report

[c4-pre-sort]

0xSorryNotSorry marked the issue as duplicate of #152

[c4-judge]

Trumpero changed the severity to QA (Quality Assurance)

[c4-judge]

Trumpero marked the issue as grade-b

[c4-judge]

Trumpero marked the issue as grade-c