First Flight #20: The Predicter
First Flight #20
Beginner FriendlyFoundry
100 EXP
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Submission Details
Severity: low
Invalid

Inconsistent State Updates in setPrediction()

bryanconquer

Vulnerability Details

The line playersPredictions[player].predictionsCount = 0; resets the predictionsCount to 0 before it loops through all matches to recalculate it based on the current predictions and payments. If an error occurs during the loop or if the loop is interrupted, the predictionsCount might not be correctly updated, leaving the state inconsistent. For example, if the loop starts but doesn't complete due to an unexpected error or gas limit, predictionsCount could be left at an incorrect value.

function setPrediction(
address player,
uint256 matchNumber,
Result result
) public {
if (block.timestamp <= START_TIME + matchNumber * 68400 - 68400)
playersPredictions[player].predictions[matchNumber] = result;
playersPredictions[player].predictionsCount = 0;
for (uint256 i = 0; i < NUM_MATCHES; ++i) {
if (
playersPredictions[player].predictions[i] != Result.Pending &&
playersPredictions[player].isPaid[i]
) ++playersPredictions[player].predictionsCount;
}
}
​

Impact

low : The predictionsCount might not be correctly updated, leaving the state inconsistent.

Tools Used

manual Review

Recommendations

By refactoring the function to separate the concerns of setting a prediction and updating the count, and by using more robust condition checks, the function becomes more reliable and efficient, reducing the risk of state inconsistencies.

Here’s a potential refactor of the setPrediction function to improve state consistency and efficiency:

function setPrediction(
address player,
uint256 matchNumber,
Result result
) public {
// Ensure the prediction is being set before the match starts
require(block.timestamp <= START_TIME + matchNumber * 68400 - 68400, "Prediction window has closed");
​
// Set the prediction for the specified match
playersPredictions[player].predictions[matchNumber] = result;
​
// Update the predictions count more efficiently
if (playersPredictions[player].isPaid[matchNumber]) {
if (result != Result.Pending) {
// Increase count if previously pending and now a valid prediction
playersPredictions[player].predictionsCount++;
} else {
// Decrease count if previously valid and now pending
playersPredictions[player].predictionsCount--;
}
}
}
​
Updates

Lead Judging Commences

NightHawK Lead Judge 11 months ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement

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