First Flight #20: The Predicter
First Flight #20
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Submission Details
Severity: medium
Valid

Incorrect Deadline Check

kapten

Finding 1: [HIGH] Incorrect Deadline Check for Prediction Functions

Summary:
The deadline check for the functions ScoreBoard:setPrediction and ThePredicter:makePrediction is implemented incorrectly.

Vulnerability Details:
The contracts allow players to make predictions until 19:00:00 UTC on the day of the match. However, the implemented check is:

if (block.timestamp > START_TIME + matchNumber * 68400 - 68400) {
revert ThePredicter__PredictionsAreClosed();
}

This translates to block.timestamp > AUG 15 20:00:00 + (MATCH_NUMBER * 19:00:00) - 19:00:00, which incorrectly blocks predictions before 19:00:00.

Proof of Concept:
A test was conducted to demonstrate the issue:

function test_wrongPredictionDeadlineCheck() public {
vm.startPrank(stranger);
vm.warp(1);
vm.deal(stranger, 1 ether);
thePredicter.register{value: 0.04 ether}();
vm.stopPrank();
vm.startPrank(organizer);
vm.warp(2);
thePredicter.approvePlayer(stranger);
vm.stopPrank();
uint256 AUG15_180000 = 1723744800; // August 15, 2024 18:00:00
vm.warp(AUG15_180000);
vm.expectRevert(
abi.encodeWithSelector(ThePredicter__PredictionsAreClosed.selector)
);
vm.startPrank(stranger);
thePredicter.makePrediction{value: 0.0001 ether}(
0,
ScoreBoard.Result.Draw
);
vm.stopPrank();
}

Impact:
High

Tools Used:

  • Manual review

  • Foundry

Recommendations:

Replace the incorrect time check with the following logic:

current_time <= AUG15 20:00:00 + (matchNumber * 86400) - 3600 // 86400 -> 1 day && 3600 -> 1 hr

Update the following lines:

  • Add at ThePredicter: line 95:

    + if (current_time <= START_TIME + (matchNumber * 86400) - 3600)

  • Add at ScoreBoard: line 73:

    + if (current_time <= START_TIME + (matchNumber * 86400) - 3600)

Remove the existing checks:

  • Remove ThePredicter: line 95:

    - if (block.timestamp > START_TIME + matchNumber * 68400 - 68400)

  • Remove ScoreBoard: line 73:

    - if (block.timestamp > START_TIME + matchNumber * 68400 - 68400)
Updates

Lead Judging Commences

NightHawK Lead Judge about 1 year ago
Submission Judgement Published
Validated
Assigned finding tags:

Match timestamps are incorrect

In both contracts there is a similar error in the computation of the timestamps of the matches.

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