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Merge remote-tracking branch 'origin/main' into remove-goerli
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@michalinacienciala
michalinacienciala committed Jan 10, 2024
2 parents 34a9332 + 44d9fc8 commit aeef5c1
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2 changes: 1 addition & 1 deletion monitoring/docs/monitoring-and-telemetry.adoc
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Expand Up @@ -181,7 +181,7 @@ team’s attention. The default action is making sure that the redemption is
not a result of a malicious action, and if not, that the redemption is
handled correctly by the system.

=== Stale redemption
==== Stale redemption

A *warning system event* indicating that a redemption request became stale, i.e.
was not handled within the expected time. This event is sent to Sentry hub and
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29 changes: 29 additions & 0 deletions solidity/contracts/bridge/Bridge.sol
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Expand Up @@ -376,6 +376,35 @@ contract Bridge is
self.revealDeposit(fundingTx, reveal);
}

/// @notice Sibling of the `revealDeposit` function. This function allows
/// to reveal a P2(W)SH Bitcoin deposit with 32-byte extra data
/// embedded in the deposit script. The extra data allows to
/// attach additional context to the deposit. For example,
/// it allows a third-party smart contract to reveal the
/// deposit on behalf of the original depositor and provide
/// additional services once the deposit is handled. In this
/// case, the address of the original depositor can be encoded
/// as extra data.
/// @param fundingTx Bitcoin funding transaction data, see `BitcoinTx.Info`.
/// @param reveal Deposit reveal data, see `RevealInfo struct.
/// @param extraData 32-byte deposit extra data.
/// @dev Requirements:
/// - All requirements from `revealDeposit` function must be met,
/// - `extraData` must not be bytes32(0),
/// - `extraData` must be the actual extra data used in the P2(W)SH
/// BTC deposit transaction.
///
/// If any of these requirements is not met, the wallet _must_ refuse
/// to sweep the deposit and the depositor has to wait until the
/// deposit script unlocks to receive their BTC back.
function revealDepositWithExtraData(
BitcoinTx.Info calldata fundingTx,
Deposit.DepositRevealInfo calldata reveal,
bytes32 extraData
) external {
self.revealDepositWithExtraData(fundingTx, reveal, extraData);
}

/// @notice Used by the wallet to prove the BTC deposit sweep transaction
/// and to update Bank balances accordingly. Sweep is only accepted
/// if it satisfies SPV proof.
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183 changes: 156 additions & 27 deletions solidity/contracts/bridge/Deposit.sol
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Expand Up @@ -44,6 +44,25 @@ import "./Wallets.sol";
/// Since each depositor has their own Ethereum address and their own
/// blinding factor, each depositor’s script is unique, and the hash
/// of each depositor’s script is unique.
///
/// This library also supports another variant of the deposit script
/// allowing to embed 32-byte extra data. The extra data allows to attach
/// additional context to the deposit. The script with 32-byte extra data
/// looks like this:
///
/// ```
/// <depositorAddress> DROP
/// <extraData> DROP
/// <blindingFactor> DROP
/// DUP HASH160 <walletPubKeyHash> EQUAL
/// IF
/// CHECKSIG
/// ELSE
/// DUP HASH160 <refundPubkeyHash> EQUALVERIFY
/// <refundLocktime> CHECKLOCKTIMEVERIFY DROP
/// CHECKSIG
/// ENDIF
/// ```
library Deposit {
using BTCUtils for bytes;
using BytesLib for bytes;
Expand Down Expand Up @@ -96,6 +115,8 @@ library Deposit {
// the time when the sweep proof was delivered to the Ethereum chain.
// XXX: Unsigned 32-bit int unix seconds, will break February 7th 2106.
uint32 sweptAt;
// The 32-byte deposit extra data. Optional, can be bytes32(0).
bytes32 extraData;
// This struct doesn't contain `__gap` property as the structure is stored
// in a mapping, mappings store values in different slots and they are
// not contiguous with other values.
Expand Down Expand Up @@ -152,6 +173,28 @@ library Deposit {
BitcoinTx.Info calldata fundingTx,
DepositRevealInfo calldata reveal
) external {
_revealDeposit(self, fundingTx, reveal, bytes32(0));
}

/// @notice Internal function encapsulating the core logic of the deposit
/// reveal process. Handles both regular deposits without extra data
/// as well as deposits with 32-byte extra data embedded in the
/// deposit script. The behavior is controlled by the `extraData`
/// parameter. If `extraData` is bytes32(0), the function triggers
/// the flow for regular deposits. If `extraData` is not bytes32(0),
/// the function triggers the flow for deposits with 32-byte
/// extra data.
/// @param fundingTx Bitcoin funding transaction data, see `BitcoinTx.Info`.
/// @param reveal Deposit reveal data, see `RevealInfo struct.
/// @param extraData 32-byte deposit extra data. Can be bytes32(0).
/// @dev Requirements are described in the docstrings of `revealDeposit` and
/// `revealDepositWithExtraData` external functions.
function _revealDeposit(
BridgeState.Storage storage self,
BitcoinTx.Info calldata fundingTx,
DepositRevealInfo calldata reveal,
bytes32 extraData
) internal {
require(
self.registeredWallets[reveal.walletPubKeyHash].state ==
Wallets.WalletState.Live,
Expand All @@ -167,33 +210,70 @@ library Deposit {
validateDepositRefundLocktime(self, reveal.refundLocktime);
}

bytes memory expectedScript = abi.encodePacked(
hex"14", // Byte length of depositor Ethereum address.
msg.sender,
hex"75", // OP_DROP
hex"08", // Byte length of blinding factor value.
reveal.blindingFactor,
hex"75", // OP_DROP
hex"76", // OP_DUP
hex"a9", // OP_HASH160
hex"14", // Byte length of a compressed Bitcoin public key hash.
reveal.walletPubKeyHash,
hex"87", // OP_EQUAL
hex"63", // OP_IF
hex"ac", // OP_CHECKSIG
hex"67", // OP_ELSE
hex"76", // OP_DUP
hex"a9", // OP_HASH160
hex"14", // Byte length of a compressed Bitcoin public key hash.
reveal.refundPubKeyHash,
hex"88", // OP_EQUALVERIFY
hex"04", // Byte length of refund locktime value.
reveal.refundLocktime,
hex"b1", // OP_CHECKLOCKTIMEVERIFY
hex"75", // OP_DROP
hex"ac", // OP_CHECKSIG
hex"68" // OP_ENDIF
);
bytes memory expectedScript;

if (extraData == bytes32(0)) {
// Regular deposit without 32-byte extra data.
expectedScript = abi.encodePacked(
hex"14", // Byte length of depositor Ethereum address.
msg.sender,
hex"75", // OP_DROP
hex"08", // Byte length of blinding factor value.
reveal.blindingFactor,
hex"75", // OP_DROP
hex"76", // OP_DUP
hex"a9", // OP_HASH160
hex"14", // Byte length of a compressed Bitcoin public key hash.
reveal.walletPubKeyHash,
hex"87", // OP_EQUAL
hex"63", // OP_IF
hex"ac", // OP_CHECKSIG
hex"67", // OP_ELSE
hex"76", // OP_DUP
hex"a9", // OP_HASH160
hex"14", // Byte length of a compressed Bitcoin public key hash.
reveal.refundPubKeyHash,
hex"88", // OP_EQUALVERIFY
hex"04", // Byte length of refund locktime value.
reveal.refundLocktime,
hex"b1", // OP_CHECKLOCKTIMEVERIFY
hex"75", // OP_DROP
hex"ac", // OP_CHECKSIG
hex"68" // OP_ENDIF
);
} else {
// Deposit with 32-byte extra data.
expectedScript = abi.encodePacked(
hex"14", // Byte length of depositor Ethereum address.
msg.sender,
hex"75", // OP_DROP
hex"20", // Byte length of extra data.
extraData,
hex"75", // OP_DROP
hex"08", // Byte length of blinding factor value.
reveal.blindingFactor,
hex"75", // OP_DROP
hex"76", // OP_DUP
hex"a9", // OP_HASH160
hex"14", // Byte length of a compressed Bitcoin public key hash.
reveal.walletPubKeyHash,
hex"87", // OP_EQUAL
hex"63", // OP_IF
hex"ac", // OP_CHECKSIG
hex"67", // OP_ELSE
hex"76", // OP_DUP
hex"a9", // OP_HASH160
hex"14", // Byte length of a compressed Bitcoin public key hash.
reveal.refundPubKeyHash,
hex"88", // OP_EQUALVERIFY
hex"04", // Byte length of refund locktime value.
reveal.refundLocktime,
hex"b1", // OP_CHECKLOCKTIMEVERIFY
hex"75", // OP_DROP
hex"ac", // OP_CHECKSIG
hex"68" // OP_ENDIF
);
}

bytes memory fundingOutput = fundingTx
.outputVector
Expand Down Expand Up @@ -258,6 +338,21 @@ library Deposit {
deposit.treasuryFee = self.depositTreasuryFeeDivisor > 0
? fundingOutputAmount / self.depositTreasuryFeeDivisor
: 0;
deposit.extraData = extraData;

_emitDepositRevealedEvent(fundingTxHash, fundingOutputAmount, reveal);
}

/// @notice Emits the `DepositRevealed` event.
/// @param fundingTxHash The funding transaction hash.
/// @param fundingOutputAmount The funding output amount in satoshi.
/// @param reveal Deposit reveal data, see `RevealInfo struct.
/// @dev This function is extracted to overcome the stack too deep error.
function _emitDepositRevealedEvent(
bytes32 fundingTxHash,
uint64 fundingOutputAmount,
DepositRevealInfo calldata reveal
) internal {
// slither-disable-next-line reentrancy-events
emit DepositRevealed(
fundingTxHash,
Expand All @@ -272,6 +367,40 @@ library Deposit {
);
}

/// @notice Sibling of the `revealDeposit` function. This function allows
/// to reveal a P2(W)SH Bitcoin deposit with 32-byte extra data
/// embedded in the deposit script. The extra data allows to
/// attach additional context to the deposit. For example,
/// it allows a third-party smart contract to reveal the
/// deposit on behalf of the original depositor and provide
/// additional services once the deposit is handled. In this
/// case, the address of the original depositor can be encoded
/// as extra data.
/// @param fundingTx Bitcoin funding transaction data, see `BitcoinTx.Info`.
/// @param reveal Deposit reveal data, see `RevealInfo struct.
/// @param extraData 32-byte deposit extra data.
/// @dev Requirements:
/// - All requirements from `revealDeposit` function must be met,
/// - `extraData` must not be bytes32(0),
/// - `extraData` must be the actual extra data used in the P2(W)SH
/// BTC deposit transaction.
///
/// If any of these requirements is not met, the wallet _must_ refuse
/// to sweep the deposit and the depositor has to wait until the
/// deposit script unlocks to receive their BTC back.
function revealDepositWithExtraData(
BridgeState.Storage storage self,
BitcoinTx.Info calldata fundingTx,
DepositRevealInfo calldata reveal,
bytes32 extraData
) external {
// Strong requirement in order to differentiate from the regular
// reveal flow and reduce potential attack surface.
require(extraData != bytes32(0), "Extra data must not be empty");

_revealDeposit(self, fundingTx, reveal, extraData);
}

/// @notice Validates the deposit refund locktime. The validation passes
/// successfully only if the deposit reveal is done respectively
/// earlier than the moment when the deposit refund locktime is
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