Potential Vault Data Collision in Extreme Scenarios

[hats-bug-reporter[bot]]

Github username: -- Twitter username: -- Submission hash (on-chain): 0x45af594e37907786efc19eea5046d4b897518936ba6dc1ee0e011e4b1bfa26dd Severity: medium

Description: Description\ In the EthMultiVault contract, the getCounterIdFromTriple function calculates the ID of a counter vault by subtracting the original vault ID from type(uint256).max. This approach works well for a reasonable number of vaults, but in an extreme scenario where the number of vaults exceeds uint256.max / 2, there's a theoretical risk of data collision between regular vaults and counter vaults.

Attack Scenario\ While highly improbable in practice, the following scenario could theoretically occur:

1. The contract continues to create new vaults until the vault ID exceeds uint256.max / 2.
2. At this point, new vault IDs start to overlap with the counter IDs of existing vaults.
3. This could lead to data corruption or unexpected behavior when interacting with these high-numbered vaults or their counters.

For example:

1. Vault with ID 2^255 is created.
2. Its counter vault ID would be 2^256 - 1 - 2^255, which equals 2^255 - 1.
3. If a new vault is later created with ID 2^255 - 1, it would collide with the counter of the first vault.

Attachments https://github.com/hats-finance/Intuition-0x538dbadc50cc87b281cd655f1edbc6ebda02a66a/blob/b2e422ff0c3e3729e58d2699fdf2ef8699fbd172/src/EthMultiVault.sol#L1354-L1355

2. Revised Code File (Optional)

   contract EthMultiVault {
   mapping(uint256 => VaultState) public vaults;
   mapping(uint256 => VaultState) public counterVaults;
   
   function getCounterIdFromTriple(uint256 id) public pure returns (uint256) {
       require(id <= type(uint256).max / 2, "Invalid vault ID");
       return id;
   }
   
   function getVaultState(uint256 id, bool isCounter) public view returns (VaultState memory) {
       if (isCounter) {
           return counterVaults[id];
       } else {
           return vaults[id];
       }
   }
   
   // Other functions would need to be updated to use the new structure
   }