Beatland Festival

AI First Flight #4
Beginner FriendlyFoundrySolidityNFT
EXP
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Submission Details
Severity: medium
Valid

`configurePass` Unconditionally Resets `passSupply` Allowing Max Supply Cap Bypass

Description

In FestivalPass.configurePass(), calling the function unconditionally overwrites passSupply[passId] = 0;.

// File: src/FestivalPass.sol
54: function configurePass(
55: uint256 passId,
56: uint256 price,
57: uint256 maxSupply
58: ) external onlyOrganizer {
...
63: passPrice[passId] = price;
64: passMaxSupply[passId] = maxSupply;
65: @> passSupply[passId] = 0; // Reset current supply
66: }

If the organizer updates the price or supply parameters after some passes have already been sold, the minted pass count is erased, permitting an additional maxSupply passes to be sold and violating the promised ticket scarcity.

Proof of Concept

function test_PoC_M02_PassSupplyResetBypass() public {
vm.prank(organizer);
festivalPass.configurePass(1, GENERAL_PRICE, 2);
vm.prank(attacker1);
festivalPass.buyPass{value: GENERAL_PRICE}(1);
vm.prank(attacker2);
festivalPass.buyPass{value: GENERAL_PRICE}(1);
// Reconfigure
vm.prank(organizer);
festivalPass.configurePass(1, GENERAL_PRICE, 2);
// passSupply was reset to 0; attacker3 can purchase extra passes
vm.prank(attacker3);
festivalPass.buyPass{value: GENERAL_PRICE}(1);
assertEq(festivalPass.balanceOf(attacker3, 1), 1);
}

Recommended Mitigation

Do not reset passSupply[passId] on reconfiguration, or enforce that maxSupply >= passSupply[passId].

- passSupply[passId] = 0; // Reset current supply
+ require(maxSupply >= passSupply[passId], "Max supply cannot be less than minted");
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge about 1 hour ago
Submission Judgement Published
Validated
Assigned finding tags:

[M-01] [H-1] Reseting the current pass supply to 0 in the FestivalPass::configurePass function allows users to bypass the max supply cap of a pass

# \[H-1] Reseting the current pass supply to `0` in the `FestivalPass::configurePass` function allows users to bypass the max supply cap of a pass ## Description: ```solidity function configurePass(uint256 passId, uint256 price, uint256 maxSupply) external onlyOrganizer { require(passId == GENERAL_PASS || passId == VIP_PASS || passId == BACKSTAGE_PASS, "Invalid pass ID"); require(price > 0, "Price must be greater than 0"); require(maxSupply > 0, "Max supply must be greater than 0"); passPrice[passId] = price; passMaxSupply[passId] = maxSupply; @> passSupply[passId] = 0; // Reset current supply } ``` If you reset `passSupply[passId]` to `0` in the `FestivalPass::configurePass` function after passes have been sold, the next buyer will be able to mint as if no passes have been sold. This allows the total minted passes to exceed `passMaxSupply`, which is a serious vulnerability (a supply cap bypass) ## Impact: * Supply caps become meaningless: The users can mint unlimited passes beyond the intended maximum supply * Pass scarcity and value are destroyed, affecting the economic model ## Proof of Concept: ```solidity function test_SupplyCapBypassVulnerability() public { // Step 1: Configure a pass with max supply of 2 vm.prank(organizer); festivalPass.configurePass(1, GENERAL_PRICE, 2); // Step 2: Buy 2 passes (reaching max supply) vm.prank(user1); festivalPass.buyPass{value: GENERAL_PRICE}(1); vm.prank(user2); festivalPass.buyPass{value: GENERAL_PRICE}(1); // Verify max supply reached assertEq(festivalPass.passSupply(1), 2); assertEq(festivalPass.passMaxSupply(1), 2); // Step 3: Try to buy another pass - should fail address user3 = makeAddr("user3"); vm.deal(user3, 10 ether); vm.prank(user3); vm.expectRevert("Max supply reached"); festivalPass.buyPass{value: GENERAL_PRICE}(1); // Step 4: VULNERABILITY - Organizer reconfigures the pass // This resets passSupply[1] to 0, bypassing the supply cap! vm.prank(organizer); festivalPass.configurePass(1, GENERAL_PRICE, 2); // Step 5: Now we can buy more passes even though max supply was already reached vm.prank(user3); festivalPass.buyPass{value: GENERAL_PRICE}(1); // Step 6: We can even buy more passes beyond the original max supply vm.deal(user4, 10 ether); vm.prank(user4); festivalPass.buyPass{value: GENERAL_PRICE}(1); // Step 7: Verify the vulnerability - total supply exceeds max supply assertEq(festivalPass.passSupply(1), 2); // Current supply counter assertEq(festivalPass.passMaxSupply(1), 2); // Max supply limit // But we actually have 4 passes minted in total! assertEq(festivalPass.balanceOf(user1, 1), 1); assertEq(festivalPass.balanceOf(user2, 1), 1); assertEq(festivalPass.balanceOf(user3, 1), 1); assertEq(festivalPass.balanceOf(user4, 1), 1); // Total minted: 4 passes, but max supply is only 2! uint256 totalMinted = festivalPass.balanceOf(user1, 1) + festivalPass.balanceOf(user2, 1) + festivalPass.balanceOf(user3, 1) + festivalPass.balanceOf(user4, 1); assertGt(totalMinted, festivalPass.passMaxSupply(1), "VULNERABILITY: Total minted exceeds max supply!"); } ``` ## Recommended Mitigation: The `passSupply` reset should be removed ```diff function configurePass(uint256 passId, uint256 price, uint256 maxSupply) external onlyOrganizer { require(passId == GENERAL_PASS || passId == VIP_PASS || passId == BACKSTAGE_PASS, "Invalid pass ID"); require(price > 0, "Price must be greater than 0"); require(maxSupply > 0, "Max supply must be greater than 0"); passPrice[passId] = price; passMaxSupply[passId] = maxSupply; - passSupply[passId] = 0; } ```

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