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to prevent replay attacks, check that this btcTxId hasnt been called … #140

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to prevent replay attacks, check that this btcTxId hasnt been called … #140

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ce6994f
to prevent replay attacks, check that this btcTxId hasnt been called …
sosaucily May 27, 2025
85ebb9d
additional refactors for readability and simplicity; include change o…
sosaucily May 28, 2025
598d363
fix typos and send correct var to revert error
sosaucily May 29, 2025
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76 changes: 53 additions & 23 deletions contracts/DLCManager.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ import "./DLCLinkLibrary.sol";
import "./IBTC.sol";

import "@chainlink/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol";
import "@openzeppelin/contracts/utils/Strings.sol";

/**
* @author DLC.Link 2024
Expand All @@ -34,6 +35,7 @@ contract DLCManager is
using DLCLink for DLCLink.DLC;
using DLCLink for DLCLink.DLCStatus;
using SafeERC20 for IBTC;
using Strings for string;

////////////////////////////////////////////////////////////////
// STATE VARIABLES //
Expand Down Expand Up @@ -70,11 +72,13 @@ contract DLCManager is
mapping(address => bool) private _whitelistedAddresses;
bool public porEnabled;
AggregatorV3Interface public dlcBTCPoRFeed;
mapping(address => mapping(bytes32 => bool)) private _seenSigners;
mapping(address => mapping(bytes32 => bool)) private _seenSigners; // deprecated
uint256 public totalValueMinted;
mapping(address => uint256) private _btcMintFeeRates;
mapping(address => uint256) private _btcRedeemFeeRates;
uint256[36] __gap;
mapping(string => bool) private _processedPendingTransactions;
mapping(string => bool) private _processedFundedTransactions;
uint256[34] __gap;

////////////////////////////////////////////////////////////////
// ERRORS //
Expand All @@ -99,6 +103,7 @@ contract DLCManager is
error DuplicateSigner(address signer);
error SignerNotApproved(address signer);
error ClosingFundedVault();
error TransactionAlreadyProcessed(string txId, string functionString);

error InvalidRange();
error NotOwner();
Expand All @@ -110,6 +115,7 @@ contract DLCManager is
error FeeRateOutOfBounds(uint256 feeRate);
error UnderCollateralized(uint256 newValueLocked, uint256 valueMinted);
error NotEnoughReserves(uint256 reserves, uint256 amount);
error InvalidFunctionString(string functionString);

////////////////////////////////////////////////////////////////
// MODIFIERS //
Expand Down Expand Up @@ -249,23 +255,40 @@ contract DLCManager is
}

/**
* @notice Checks the 'signatures' of Attestors for a given 'message'.
* @notice Checks the signatures of Attestors for a given transaction.
* @dev Recalculates the hash to make sure the signatures are for the same message.
* @dev Uses OpenZeppelin's ECDSA library to recover the public keys from the signatures.
* @dev Signatures must be unique, from unique signers.
* @param message Original message that was signed.
* @param signatures Byte array of at least 'threshold' number of signatures.
* @dev Checks if the btc transaction has already been processed for this function signature.
* @param uuid Unique identifier for the transaction
* @param btcTxId Bitcoin transaction ID
* @param newValueLocked New value locked in the transaction
* @param signatures Byte array of at least 'threshold' number of signatures
* @param functionString String identifying the function being called
*/
function _attestorMultisigIsValid(
bytes memory message,
bytes[] memory signatures
) internal {
bytes32 uuid,
string memory btcTxId,
uint256 newValueLocked,
bytes[] memory signatures,
string memory functionString
) internal view {
if (signatures.length < _threshold) revert NotEnoughSignatures();

bytes32 prefixedMessageHash = ECDSAUpgradeable.toEthSignedMessageHash(
keccak256(message)
keccak256(abi.encode(uuid, btcTxId, functionString, newValueLocked))
);

if (
(Strings.equal(functionString, "set-status-pending") &&
_processedPendingTransactions[btcTxId]) ||
(Strings.equal(functionString, "set-status-funded") &&
_processedFundedTransactions[btcTxId])
) {
revert TransactionAlreadyProcessed(btcTxId, functionString);
}

address[] memory seenSigners = new address[](signatures.length);
for (uint256 i = 0; i < signatures.length; i++) {
address attestorPubKey = ECDSAUpgradeable.recover(
prefixedMessageHash,
Expand All @@ -274,18 +297,15 @@ contract DLCManager is
if (!hasRole(APPROVED_SIGNER, attestorPubKey)) {
revert InvalidSigner();
}
_checkSignerUnique(attestorPubKey, prefixedMessageHash);
}
}

function _checkSignerUnique(
address attestorPubKey,
bytes32 messageHash
) internal {
if (_seenSigners[attestorPubKey][messageHash]) {
revert DuplicateSigner(attestorPubKey);
// Check for duplicates in already seen signers
for (uint256 j = 0; j < i; j++) {
if (seenSigners[j] == attestorPubKey) {
revert DuplicateSigner(attestorPubKey);
}
}
seenSigners[i] = attestorPubKey;
}
_seenSigners[attestorPubKey][messageHash] = true;
}

/**
Expand Down Expand Up @@ -401,8 +421,11 @@ contract DLCManager is
uint256 newValueLocked
) external whenNotPaused onlyApprovedSigners {
_attestorMultisigIsValid(
abi.encode(uuid, btcTxId, "set-status-funded", newValueLocked),
signatures
uuid,
btcTxId,
newValueLocked,
signatures,
"set-status-funded"
);
DLCLink.DLC storage dlc = dlcs[dlcIDsByUUID[uuid]];

Expand Down Expand Up @@ -440,6 +463,8 @@ contract DLCManager is
_mintTokens(dlc.creator, amountToMint);
}

_processedFundedTransactions[btcTxId] = true;

emit SetStatusFunded(
uuid,
btcTxId,
Expand All @@ -466,8 +491,11 @@ contract DLCManager is
uint256 newValueLocked
) external whenNotPaused onlyApprovedSigners {
_attestorMultisigIsValid(
abi.encode(uuid, wdTxId, "set-status-pending", newValueLocked),
signatures
uuid,
wdTxId,
newValueLocked,
signatures,
"set-status-pending"
);
DLCLink.DLC storage dlc = dlcs[dlcIDsByUUID[uuid]];

Expand All @@ -481,6 +509,8 @@ contract DLCManager is
dlc.wdTxId = wdTxId;
dlc.taprootPubKey = taprootPubKey;

_processedPendingTransactions[wdTxId] = true;

emit SetStatusPending(
uuid,
wdTxId,
Expand Down
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