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-rw-r--r--packages/contracts/src/2.0.0/examples/Whitelist/Whitelist.sol2
-rw-r--r--packages/contracts/src/2.0.0/extensions/Forwarder/MixinExchangeWrapper.sol14
-rw-r--r--packages/contracts/src/2.0.0/extensions/Forwarder/MixinForwarderCore.sol4
-rw-r--r--packages/contracts/src/2.0.0/extensions/Forwarder/MixinWeth.sol2
-rw-r--r--packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol3
-rw-r--r--packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol3
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol2
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol195
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol132
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol172
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol3
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol63
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol198
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol35
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol41
-rw-r--r--packages/contracts/src/2.0.0/protocol/Exchange/mixins/MWrapperFunctions.sol40
-rw-r--r--packages/contracts/src/2.0.0/test/ReentrantERC20Token/ReentrantERC20Token.sol183
-rw-r--r--packages/contracts/src/2.0.0/test/TestExchangeInternals/TestExchangeInternals.sol80
-rw-r--r--packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol42
-rw-r--r--packages/contracts/src/2.0.0/test/TestStaticCallReceiver/TestStaticCallReceiver.sol81
-rw-r--r--packages/contracts/src/2.0.0/utils/ReentrancyGuard/ReentrancyGuard.sol44
21 files changed, 1109 insertions, 230 deletions
diff --git a/packages/contracts/src/2.0.0/examples/Whitelist/Whitelist.sol b/packages/contracts/src/2.0.0/examples/Whitelist/Whitelist.sol
index 60cac26ea..e4e25038c 100644
--- a/packages/contracts/src/2.0.0/examples/Whitelist/Whitelist.sol
+++ b/packages/contracts/src/2.0.0/examples/Whitelist/Whitelist.sol
@@ -37,7 +37,7 @@ contract Whitelist is
bytes internal TX_ORIGIN_SIGNATURE;
// solhint-enable var-name-mixedcase
- byte constant internal VALIDATOR_SIGNATURE_BYTE = "\x06";
+ byte constant internal VALIDATOR_SIGNATURE_BYTE = "\x05";
constructor (address _exchange)
public
diff --git a/packages/contracts/src/2.0.0/extensions/Forwarder/MixinExchangeWrapper.sol b/packages/contracts/src/2.0.0/extensions/Forwarder/MixinExchangeWrapper.sol
index 218713d3c..9e816716c 100644
--- a/packages/contracts/src/2.0.0/extensions/Forwarder/MixinExchangeWrapper.sol
+++ b/packages/contracts/src/2.0.0/extensions/Forwarder/MixinExchangeWrapper.sol
@@ -69,20 +69,14 @@ contract MixinExchangeWrapper is
fillOrderCalldata, // write output over input
128 // output size is 128 bytes
)
- switch success
- case 0 {
- mstore(fillResults, 0)
- mstore(add(fillResults, 32), 0)
- mstore(add(fillResults, 64), 0)
- mstore(add(fillResults, 96), 0)
- }
- case 1 {
+ if success {
mstore(fillResults, mload(fillOrderCalldata))
mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32)))
mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64)))
mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96)))
}
}
+ // fillResults values will be 0 by default if call was unsuccessful
return fillResults;
}
@@ -163,7 +157,7 @@ contract MixinExchangeWrapper is
// Convert the remaining amount of makerAsset to buy into remaining amount
// of takerAsset to sell, assuming entire amount can be sold in the current order
- uint256 remainingTakerAssetFillAmount = getPartialAmount(
+ uint256 remainingTakerAssetFillAmount = getPartialAmountFloor(
orders[i].takerAssetAmount,
orders[i].makerAssetAmount,
remainingMakerAssetFillAmount
@@ -231,7 +225,7 @@ contract MixinExchangeWrapper is
// Convert the remaining amount of ZRX to buy into remaining amount
// of WETH to sell, assuming entire amount can be sold in the current order.
- uint256 remainingWethSellAmount = getPartialAmount(
+ uint256 remainingWethSellAmount = getPartialAmountFloor(
orders[i].takerAssetAmount,
safeSub(orders[i].makerAssetAmount, orders[i].takerFee), // our exchange rate after fees
remainingZrxBuyAmount
diff --git a/packages/contracts/src/2.0.0/extensions/Forwarder/MixinForwarderCore.sol b/packages/contracts/src/2.0.0/extensions/Forwarder/MixinForwarderCore.sol
index 42cec4d36..14f191879 100644
--- a/packages/contracts/src/2.0.0/extensions/Forwarder/MixinForwarderCore.sol
+++ b/packages/contracts/src/2.0.0/extensions/Forwarder/MixinForwarderCore.sol
@@ -87,7 +87,7 @@ contract MixinForwarderCore is
uint256 makerAssetAmountPurchased;
if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
// Calculate amount of WETH that won't be spent on ETH fees.
- wethSellAmount = getPartialAmount(
+ wethSellAmount = getPartialAmountFloor(
PERCENTAGE_DENOMINATOR,
safeAdd(PERCENTAGE_DENOMINATOR, feePercentage),
msg.value
@@ -103,7 +103,7 @@ contract MixinForwarderCore is
makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
} else {
// 5% of WETH is reserved for filling feeOrders and paying feeRecipient.
- wethSellAmount = getPartialAmount(
+ wethSellAmount = getPartialAmountFloor(
MAX_WETH_FILL_PERCENTAGE,
PERCENTAGE_DENOMINATOR,
msg.value
diff --git a/packages/contracts/src/2.0.0/extensions/Forwarder/MixinWeth.sol b/packages/contracts/src/2.0.0/extensions/Forwarder/MixinWeth.sol
index 93e85e599..5863b522d 100644
--- a/packages/contracts/src/2.0.0/extensions/Forwarder/MixinWeth.sol
+++ b/packages/contracts/src/2.0.0/extensions/Forwarder/MixinWeth.sol
@@ -82,7 +82,7 @@ contract MixinWeth is
uint256 wethRemaining = safeSub(msg.value, wethSold);
// Calculate ETH fee to pay to feeRecipient.
- uint256 ethFee = getPartialAmount(
+ uint256 ethFee = getPartialAmountFloor(
feePercentage,
PERCENTAGE_DENOMINATOR,
wethSoldExcludingFeeOrders
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
index b5cec6b64..004c3892d 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
@@ -118,6 +118,9 @@ contract ERC20Proxy is
mstore(96, 0)
revert(0, 100)
}
+
+ // Revert if undefined function is called
+ revert(0, 0)
}
}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
index 6a70c9f60..9d0bc0f74 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
@@ -152,6 +152,9 @@ contract ERC721Proxy is
mstore(96, 0)
revert(0, 100)
}
+
+ // Revert if undefined function is called
+ revert(0, 0)
}
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
index e9f882194..80475e6e3 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -83,7 +83,7 @@ contract MixinAssetProxyDispatcher is
internal
{
// Do nothing if no amount should be transferred.
- if (amount > 0) {
+ if (amount > 0 && from != to) {
// Ensure assetData length is valid
require(
assetData.length > 3,
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
index ab5c6e507..ff908917d 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
@@ -19,6 +19,7 @@
pragma solidity 0.4.24;
pragma experimental ABIEncoderV2;
+import "../../utils/ReentrancyGuard/ReentrancyGuard.sol";
import "./libs/LibConstants.sol";
import "./libs/LibFillResults.sol";
import "./libs/LibOrder.sol";
@@ -30,6 +31,7 @@ import "./mixins/MAssetProxyDispatcher.sol";
contract MixinExchangeCore is
+ ReentrancyGuard,
LibConstants,
LibMath,
LibOrder,
@@ -54,6 +56,7 @@ contract MixinExchangeCore is
/// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
function cancelOrdersUpTo(uint256 targetOrderEpoch)
external
+ nonReentrant
{
address makerAddress = getCurrentContextAddress();
// If this function is called via `executeTransaction`, we only update the orderEpoch for the makerAddress/msg.sender combination.
@@ -86,43 +89,14 @@ contract MixinExchangeCore is
bytes memory signature
)
public
+ nonReentrant
returns (FillResults memory fillResults)
{
- // Fetch order info
- OrderInfo memory orderInfo = getOrderInfo(order);
-
- // Fetch taker address
- address takerAddress = getCurrentContextAddress();
-
- // Get amount of takerAsset to fill
- uint256 remainingTakerAssetAmount = safeSub(order.takerAssetAmount, orderInfo.orderTakerAssetFilledAmount);
- uint256 takerAssetFilledAmount = min256(takerAssetFillAmount, remainingTakerAssetAmount);
-
- // Validate context
- assertValidFill(
+ fillResults = fillOrderInternal(
order,
- orderInfo,
- takerAddress,
takerAssetFillAmount,
- takerAssetFilledAmount,
signature
);
-
- // Compute proportional fill amounts
- fillResults = calculateFillResults(order, takerAssetFilledAmount);
-
- // Update exchange internal state
- updateFilledState(
- order,
- takerAddress,
- orderInfo.orderHash,
- orderInfo.orderTakerAssetFilledAmount,
- fillResults
- );
-
- // Settle order
- settleOrder(order, takerAddress, fillResults);
-
return fillResults;
}
@@ -131,6 +105,7 @@ contract MixinExchangeCore is
/// @param order Order to cancel. Order must be OrderStatus.FILLABLE.
function cancelOrder(Order memory order)
public
+ nonReentrant
{
// Fetch current order status
OrderInfo memory orderInfo = getOrderInfo(order);
@@ -203,6 +178,64 @@ contract MixinExchangeCore is
return orderInfo;
}
+ /// @dev Fills the input order.
+ /// @param order Order struct containing order specifications.
+ /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+ /// @param signature Proof that order has been created by maker.
+ /// @return Amounts filled and fees paid by maker and taker.
+ function fillOrderInternal(
+ Order memory order,
+ uint256 takerAssetFillAmount,
+ bytes memory signature
+ )
+ internal
+ returns (FillResults memory fillResults)
+ {
+ // Fetch order info
+ OrderInfo memory orderInfo = getOrderInfo(order);
+
+ // Fetch taker address
+ address takerAddress = getCurrentContextAddress();
+
+ // Assert that the order is fillable by taker
+ assertFillableOrder(
+ order,
+ orderInfo,
+ takerAddress,
+ signature
+ );
+
+ // Get amount of takerAsset to fill
+ uint256 remainingTakerAssetAmount = safeSub(order.takerAssetAmount, orderInfo.orderTakerAssetFilledAmount);
+ uint256 takerAssetFilledAmount = min256(takerAssetFillAmount, remainingTakerAssetAmount);
+
+ // Validate context
+ assertValidFill(
+ order,
+ orderInfo,
+ takerAssetFillAmount,
+ takerAssetFilledAmount,
+ fillResults.makerAssetFilledAmount
+ );
+
+ // Compute proportional fill amounts
+ fillResults = calculateFillResults(order, takerAssetFilledAmount);
+
+ // Update exchange internal state
+ updateFilledState(
+ order,
+ takerAddress,
+ orderInfo.orderHash,
+ orderInfo.orderTakerAssetFilledAmount,
+ fillResults
+ );
+
+ // Settle order
+ settleOrder(order, takerAddress, fillResults);
+
+ return fillResults;
+ }
+
/// @dev Updates state with results of a fill order.
/// @param order that was filled.
/// @param takerAddress Address of taker who filled the order.
@@ -259,20 +292,16 @@ contract MixinExchangeCore is
order.takerAssetData
);
}
-
+
/// @dev Validates context for fillOrder. Succeeds or throws.
/// @param order to be filled.
/// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
/// @param takerAddress Address of order taker.
- /// @param takerAssetFillAmount Desired amount of order to fill by taker.
- /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
/// @param signature Proof that the orders was created by its maker.
- function assertValidFill(
+ function assertFillableOrder(
Order memory order,
OrderInfo memory orderInfo,
address takerAddress,
- uint256 takerAssetFillAmount,
- uint256 takerAssetFilledAmount,
bytes memory signature
)
internal
@@ -283,13 +312,7 @@ contract MixinExchangeCore is
orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
"ORDER_UNFILLABLE"
);
-
- // Revert if fill amount is invalid
- require(
- takerAssetFillAmount != 0,
- "INVALID_TAKER_AMOUNT"
- );
-
+
// Validate sender is allowed to fill this order
if (order.senderAddress != address(0)) {
require(
@@ -297,7 +320,7 @@ contract MixinExchangeCore is
"INVALID_SENDER"
);
}
-
+
// Validate taker is allowed to fill this order
if (order.takerAddress != address(0)) {
require(
@@ -305,7 +328,7 @@ contract MixinExchangeCore is
"INVALID_TAKER"
);
}
-
+
// Validate Maker signature (check only if first time seen)
if (orderInfo.orderTakerAssetFilledAmount == 0) {
require(
@@ -317,15 +340,69 @@ contract MixinExchangeCore is
"INVALID_ORDER_SIGNATURE"
);
}
-
- // Validate fill order rounding
+ }
+
+ /// @dev Validates context for fillOrder. Succeeds or throws.
+ /// @param order to be filled.
+ /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
+ /// @param takerAssetFillAmount Desired amount of order to fill by taker.
+ /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
+ /// @param makerAssetFilledAmount Amount of makerAsset that will be transfered.
+ function assertValidFill(
+ Order memory order,
+ OrderInfo memory orderInfo,
+ uint256 takerAssetFillAmount, // TODO: use FillResults
+ uint256 takerAssetFilledAmount,
+ uint256 makerAssetFilledAmount
+ )
+ internal
+ view
+ {
+ // Revert if fill amount is invalid
+ // TODO: reconsider necessity for v2.1
+ require(
+ takerAssetFillAmount != 0,
+ "INVALID_TAKER_AMOUNT"
+ );
+
+ // Make sure taker does not pay more than desired amount
+ // NOTE: This assertion should never fail, it is here
+ // as an extra defence against potential bugs.
+ require(
+ takerAssetFilledAmount <= takerAssetFillAmount,
+ "TAKER_OVERPAY"
+ );
+
+ // Make sure order is not overfilled
+ // NOTE: This assertion should never fail, it is here
+ // as an extra defence against potential bugs.
+ require(
+ safeAdd(orderInfo.orderTakerAssetFilledAmount, takerAssetFilledAmount) <= order.takerAssetAmount,
+ "ORDER_OVERFILL"
+ );
+
+ // Make sure order is filled at acceptable price.
+ // The order has an implied price from the makers perspective:
+ // order price = order.makerAssetAmount / order.takerAssetAmount
+ // i.e. the number of makerAsset maker is paying per takerAsset. The
+ // maker is guaranteed to get this price or a better (lower) one. The
+ // actual price maker is getting in this fill is:
+ // fill price = makerAssetFilledAmount / takerAssetFilledAmount
+ // We need `fill price <= order price` for the fill to be fair to maker.
+ // This amounts to:
+ // makerAssetFilledAmount order.makerAssetAmount
+ // ------------------------ <= -----------------------
+ // takerAssetFilledAmount order.takerAssetAmount
+ // or, equivalently:
+ // makerAssetFilledAmount * order.takerAssetAmount <=
+ // order.makerAssetAmount * takerAssetFilledAmount
+ // NOTE: This assertion should never fail, it is here
+ // as an extra defence against potential bugs.
require(
- !isRoundingError(
- takerAssetFilledAmount,
- order.takerAssetAmount,
- order.makerAssetAmount
- ),
- "ROUNDING_ERROR"
+ safeMul(makerAssetFilledAmount, order.takerAssetAmount)
+ <=
+ safeMul(order.makerAssetAmount, takerAssetFilledAmount),
+ "INVALID_FILL_PRICE"
);
}
@@ -376,17 +453,17 @@ contract MixinExchangeCore is
{
// Compute proportional transfer amounts
fillResults.takerAssetFilledAmount = takerAssetFilledAmount;
- fillResults.makerAssetFilledAmount = getPartialAmount(
+ fillResults.makerAssetFilledAmount = safeGetPartialAmountFloor(
takerAssetFilledAmount,
order.takerAssetAmount,
order.makerAssetAmount
);
- fillResults.makerFeePaid = getPartialAmount(
- takerAssetFilledAmount,
- order.takerAssetAmount,
+ fillResults.makerFeePaid = safeGetPartialAmountFloor(
+ fillResults.makerAssetFilledAmount,
+ order.makerAssetAmount,
order.makerFee
);
- fillResults.takerFeePaid = getPartialAmount(
+ fillResults.takerFeePaid = safeGetPartialAmountFloor(
takerAssetFilledAmount,
order.takerAssetAmount,
order.takerFee
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
index 56b309a1b..b4f6bdb26 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
@@ -14,6 +14,7 @@
pragma solidity 0.4.24;
pragma experimental ABIEncoderV2;
+import "../../utils/ReentrancyGuard/ReentrancyGuard.sol";
import "./libs/LibConstants.sol";
import "./libs/LibMath.sol";
import "./libs/LibOrder.sol";
@@ -25,6 +26,7 @@ import "./mixins/MAssetProxyDispatcher.sol";
contract MixinMatchOrders is
+ ReentrancyGuard,
LibConstants,
LibMath,
MAssetProxyDispatcher,
@@ -48,6 +50,7 @@ contract MixinMatchOrders is
bytes memory rightSignature
)
public
+ nonReentrant
returns (LibFillResults.MatchedFillResults memory matchedFillResults)
{
// We assume that rightOrder.takerAssetData == leftOrder.makerAssetData and rightOrder.makerAssetData == leftOrder.takerAssetData.
@@ -61,8 +64,20 @@ contract MixinMatchOrders is
// Fetch taker address
address takerAddress = getCurrentContextAddress();
-
+
// Either our context is valid or we revert
+ assertFillableOrder(
+ leftOrder,
+ leftOrderInfo,
+ takerAddress,
+ leftSignature
+ );
+ assertFillableOrder(
+ rightOrder,
+ rightOrderInfo,
+ takerAddress,
+ rightSignature
+ );
assertValidMatch(leftOrder, rightOrder);
// Compute proportional fill amounts
@@ -77,20 +92,18 @@ contract MixinMatchOrders is
assertValidFill(
leftOrder,
leftOrderInfo,
- takerAddress,
matchedFillResults.left.takerAssetFilledAmount,
matchedFillResults.left.takerAssetFilledAmount,
- leftSignature
+ matchedFillResults.left.makerAssetFilledAmount
);
assertValidFill(
rightOrder,
rightOrderInfo,
- takerAddress,
matchedFillResults.right.takerAssetFilledAmount,
matchedFillResults.right.takerAssetFilledAmount,
- rightSignature
+ matchedFillResults.right.makerAssetFilledAmount
);
-
+
// Update exchange state
updateFilledState(
leftOrder,
@@ -106,7 +119,7 @@ contract MixinMatchOrders is
rightOrderInfo.orderTakerAssetFilledAmount,
matchedFillResults.right
);
-
+
// Settle matched orders. Succeeds or throws.
settleMatchedOrders(
leftOrder,
@@ -162,62 +175,85 @@ contract MixinMatchOrders is
pure
returns (LibFillResults.MatchedFillResults memory matchedFillResults)
{
- // We settle orders at the exchange rate of the right order.
- // The amount saved by the left maker goes to the taker.
- // Either the left or right order will be fully filled; possibly both.
- // The left order is fully filled iff the right order can sell more than left can buy.
- // That is: the amount required to fill the left order is less than or equal to
- // the amount we can spend from the right order:
- // <leftTakerAssetAmountRemaining> <= <rightTakerAssetAmountRemaining> * <rightMakerToTakerRatio>
- // <leftTakerAssetAmountRemaining> <= <rightTakerAssetAmountRemaining> * <rightOrder.makerAssetAmount> / <rightOrder.takerAssetAmount>
- // <leftTakerAssetAmountRemaining> * <rightOrder.takerAssetAmount> <= <rightTakerAssetAmountRemaining> * <rightOrder.makerAssetAmount>
+ // Derive maker asset amounts for left & right orders, given store taker assert amounts
uint256 leftTakerAssetAmountRemaining = safeSub(leftOrder.takerAssetAmount, leftOrderTakerAssetFilledAmount);
+ uint256 leftMakerAssetAmountRemaining = safeGetPartialAmountFloor(
+ leftOrder.makerAssetAmount,
+ leftOrder.takerAssetAmount,
+ leftTakerAssetAmountRemaining
+ );
uint256 rightTakerAssetAmountRemaining = safeSub(rightOrder.takerAssetAmount, rightOrderTakerAssetFilledAmount);
- uint256 leftTakerAssetFilledAmount;
- uint256 rightTakerAssetFilledAmount;
- if (
- safeMul(leftTakerAssetAmountRemaining, rightOrder.takerAssetAmount) <=
- safeMul(rightTakerAssetAmountRemaining, rightOrder.makerAssetAmount)
- ) {
- // Left order will be fully filled: maximally fill left
- leftTakerAssetFilledAmount = leftTakerAssetAmountRemaining;
+ uint256 rightMakerAssetAmountRemaining = safeGetPartialAmountFloor(
+ rightOrder.makerAssetAmount,
+ rightOrder.takerAssetAmount,
+ rightTakerAssetAmountRemaining
+ );
- // The right order receives an amount proportional to how much was spent.
- rightTakerAssetFilledAmount = getPartialAmount(
- rightOrder.takerAssetAmount,
- rightOrder.makerAssetAmount,
- leftTakerAssetFilledAmount
+ // Calculate fill results for maker and taker assets: at least one order will be fully filled.
+ // The maximum amount the left maker can buy is `leftTakerAssetAmountRemaining`
+ // The maximum amount the right maker can sell is `rightMakerAssetAmountRemaining`
+ // We have two distinct cases for calculating the fill results:
+ // Case 1.
+ // If the left maker can buy more than the right maker can sell, then only the right order is fully filled.
+ // If the left maker can buy exactly what the right maker can sell, then both orders are fully filled.
+ // Case 2.
+ // If the left maker cannot buy more than the right maker can sell, then only the left order is fully filled.
+ if (leftTakerAssetAmountRemaining >= rightMakerAssetAmountRemaining) {
+ // Case 1: Right order is fully filled
+ matchedFillResults.right.makerAssetFilledAmount = rightMakerAssetAmountRemaining;
+ matchedFillResults.right.takerAssetFilledAmount = rightTakerAssetAmountRemaining;
+ matchedFillResults.left.takerAssetFilledAmount = matchedFillResults.right.makerAssetFilledAmount;
+ // Round down to ensure the maker's exchange rate does not exceed the price specified by the order.
+ // We favor the maker when the exchange rate must be rounded.
+ matchedFillResults.left.makerAssetFilledAmount = safeGetPartialAmountFloor(
+ leftOrder.makerAssetAmount,
+ leftOrder.takerAssetAmount,
+ matchedFillResults.left.takerAssetFilledAmount
);
} else {
- // Right order will be fully filled: maximally fill right
- rightTakerAssetFilledAmount = rightTakerAssetAmountRemaining;
-
- // The left order receives an amount proportional to how much was spent.
- leftTakerAssetFilledAmount = getPartialAmount(
- rightOrder.makerAssetAmount,
+ // Case 2: Left order is fully filled
+ matchedFillResults.left.makerAssetFilledAmount = leftMakerAssetAmountRemaining;
+ matchedFillResults.left.takerAssetFilledAmount = leftTakerAssetAmountRemaining;
+ matchedFillResults.right.makerAssetFilledAmount = matchedFillResults.left.takerAssetFilledAmount;
+ // Round up to ensure the maker's exchange rate does not exceed the price specified by the order.
+ // We favor the maker when the exchange rate must be rounded.
+ matchedFillResults.right.takerAssetFilledAmount = safeGetPartialAmountCeil(
rightOrder.takerAssetAmount,
- rightTakerAssetFilledAmount
+ rightOrder.makerAssetAmount,
+ matchedFillResults.right.makerAssetFilledAmount
);
}
- // Calculate fill results for left order
- matchedFillResults.left = calculateFillResults(
- leftOrder,
- leftTakerAssetFilledAmount
- );
-
- // Calculate fill results for right order
- matchedFillResults.right = calculateFillResults(
- rightOrder,
- rightTakerAssetFilledAmount
- );
-
// Calculate amount given to taker
matchedFillResults.leftMakerAssetSpreadAmount = safeSub(
matchedFillResults.left.makerAssetFilledAmount,
matchedFillResults.right.takerAssetFilledAmount
);
+ // Compute fees for left order
+ matchedFillResults.left.makerFeePaid = safeGetPartialAmountFloor(
+ matchedFillResults.left.makerAssetFilledAmount,
+ leftOrder.makerAssetAmount,
+ leftOrder.makerFee
+ );
+ matchedFillResults.left.takerFeePaid = safeGetPartialAmountFloor(
+ matchedFillResults.left.takerAssetFilledAmount,
+ leftOrder.takerAssetAmount,
+ leftOrder.takerFee
+ );
+
+ // Compute fees for right order
+ matchedFillResults.right.makerFeePaid = safeGetPartialAmountFloor(
+ matchedFillResults.right.makerAssetFilledAmount,
+ rightOrder.makerAssetAmount,
+ rightOrder.makerFee
+ );
+ matchedFillResults.right.takerFeePaid = safeGetPartialAmountFloor(
+ matchedFillResults.right.takerAssetFilledAmount,
+ rightOrder.takerAssetAmount,
+ rightOrder.takerFee
+ );
+
// Return fill results
return matchedFillResults;
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
index 44de54817..4eb6a2fa6 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
@@ -19,6 +19,7 @@
pragma solidity 0.4.24;
import "../../utils/LibBytes/LibBytes.sol";
+import "../../utils/ReentrancyGuard/ReentrancyGuard.sol";
import "./mixins/MSignatureValidator.sol";
import "./mixins/MTransactions.sol";
import "./interfaces/IWallet.sol";
@@ -26,6 +27,7 @@ import "./interfaces/IValidator.sol";
contract MixinSignatureValidator is
+ ReentrancyGuard,
MSignatureValidator,
MTransactions
{
@@ -48,14 +50,16 @@ contract MixinSignatureValidator is
)
external
{
- require(
- isValidSignature(
- hash,
- signerAddress,
- signature
- ),
- "INVALID_SIGNATURE"
- );
+ if (signerAddress != msg.sender) {
+ require(
+ isValidSignature(
+ hash,
+ signerAddress,
+ signature
+ ),
+ "INVALID_SIGNATURE"
+ );
+ }
preSigned[hash][signerAddress] = true;
}
@@ -67,6 +71,7 @@ contract MixinSignatureValidator is
bool approval
)
external
+ nonReentrant
{
address signerAddress = getCurrentContextAddress();
allowedValidators[signerAddress][validatorAddress] = approval;
@@ -172,26 +177,14 @@ contract MixinSignatureValidator is
isValid = signerAddress == recovered;
return isValid;
- // Implicitly signed by caller.
- // The signer has initiated the call. In the case of non-contract
- // accounts it means the transaction itself was signed.
- // Example: let's say for a particular operation three signatures
- // A, B and C are required. To submit the transaction, A and B can
- // give a signature to C, who can then submit the transaction using
- // `Caller` for his own signature. Or A and C can sign and B can
- // submit using `Caller`. Having `Caller` allows this flexibility.
- } else if (signatureType == SignatureType.Caller) {
- require(
- signature.length == 0,
- "LENGTH_0_REQUIRED"
- );
- isValid = signerAddress == msg.sender;
- return isValid;
-
// Signature verified by wallet contract.
// If used with an order, the maker of the order is the wallet contract.
} else if (signatureType == SignatureType.Wallet) {
- isValid = IWallet(signerAddress).isValidSignature(hash, signature);
+ isValid = isValidWalletSignature(
+ hash,
+ signerAddress,
+ signature
+ );
return isValid;
// Signature verified by validator contract.
@@ -209,7 +202,8 @@ contract MixinSignatureValidator is
if (!allowedValidators[signerAddress][validatorAddress]) {
return false;
}
- isValid = IValidator(validatorAddress).isValidSignature(
+ isValid = isValidValidatorSignature(
+ validatorAddress,
hash,
signerAddress,
signature
@@ -220,34 +214,6 @@ contract MixinSignatureValidator is
} else if (signatureType == SignatureType.PreSigned) {
isValid = preSigned[hash][signerAddress];
return isValid;
-
- // Signature from Trezor hardware wallet.
- // It differs from web3.eth_sign in the encoding of message length
- // (Bitcoin varint encoding vs ascii-decimal, the latter is not
- // self-terminating which leads to ambiguities).
- // See also:
- // https://en.bitcoin.it/wiki/Protocol_documentation#Variable_length_integer
- // https://github.com/trezor/trezor-mcu/blob/master/firmware/ethereum.c#L602
- // https://github.com/trezor/trezor-mcu/blob/master/firmware/crypto.c#L36
- } else if (signatureType == SignatureType.Trezor) {
- require(
- signature.length == 65,
- "LENGTH_65_REQUIRED"
- );
- v = uint8(signature[0]);
- r = signature.readBytes32(1);
- s = signature.readBytes32(33);
- recovered = ecrecover(
- keccak256(abi.encodePacked(
- "\x19Ethereum Signed Message:\n\x20",
- hash
- )),
- v,
- r,
- s
- );
- isValid = signerAddress == recovered;
- return isValid;
}
// Anything else is illegal (We do not return false because
@@ -257,4 +223,102 @@ contract MixinSignatureValidator is
// signature was invalid.)
revert("SIGNATURE_UNSUPPORTED");
}
+
+ /// @dev Verifies signature using logic defined by Wallet contract.
+ /// @param hash Any 32 byte hash.
+ /// @param walletAddress Address that should have signed the given hash
+ /// and defines its own signature verification method.
+ /// @param signature Proof that the hash has been signed by signer.
+ /// @return True if signature is valid for given wallet..
+ function isValidWalletSignature(
+ bytes32 hash,
+ address walletAddress,
+ bytes signature
+ )
+ internal
+ view
+ returns (bool isValid)
+ {
+ bytes memory calldata = abi.encodeWithSelector(
+ IWallet(walletAddress).isValidSignature.selector,
+ hash,
+ signature
+ );
+ assembly {
+ let cdStart := add(calldata, 32)
+ let success := staticcall(
+ gas, // forward all gas
+ walletAddress, // address of Wallet contract
+ cdStart, // pointer to start of input
+ mload(calldata), // length of input
+ cdStart, // write input over output
+ 32 // output size is 32 bytes
+ )
+
+ switch success
+ case 0 {
+ // Revert with `Error("WALLET_ERROR")`
+ mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+ mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+ mstore(64, 0x0000000c57414c4c45545f4552524f5200000000000000000000000000000000)
+ mstore(96, 0)
+ revert(0, 100)
+ }
+ case 1 {
+ // Signature is valid if call did not revert and returned true
+ isValid := mload(cdStart)
+ }
+ }
+ return isValid;
+ }
+
+ /// @dev Verifies signature using logic defined by Validator contract.
+ /// @param validatorAddress Address of validator contract.
+ /// @param hash Any 32 byte hash.
+ /// @param signerAddress Address that should have signed the given hash.
+ /// @param signature Proof that the hash has been signed by signer.
+ /// @return True if the address recovered from the provided signature matches the input signer address.
+ function isValidValidatorSignature(
+ address validatorAddress,
+ bytes32 hash,
+ address signerAddress,
+ bytes signature
+ )
+ internal
+ view
+ returns (bool isValid)
+ {
+ bytes memory calldata = abi.encodeWithSelector(
+ IValidator(signerAddress).isValidSignature.selector,
+ hash,
+ signerAddress,
+ signature
+ );
+ assembly {
+ let cdStart := add(calldata, 32)
+ let success := staticcall(
+ gas, // forward all gas
+ validatorAddress, // address of Validator contract
+ cdStart, // pointer to start of input
+ mload(calldata), // length of input
+ cdStart, // write input over output
+ 32 // output size is 32 bytes
+ )
+
+ switch success
+ case 0 {
+ // Revert with `Error("VALIDATOR_ERROR")`
+ mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+ mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+ mstore(64, 0x0000000f56414c494441544f525f4552524f5200000000000000000000000000)
+ mstore(96, 0)
+ revert(0, 100)
+ }
+ case 1 {
+ // Signature is valid if call did not revert and returned true
+ isValid := mload(cdStart)
+ }
+ }
+ return isValid;
+ }
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
index 821d30279..4a59b6c0f 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
@@ -155,7 +155,8 @@ contract MixinTransactions is
view
returns (address)
{
- address contextAddress = currentContextAddress == address(0) ? msg.sender : currentContextAddress;
+ address currentContextAddress_ = currentContextAddress;
+ address contextAddress = currentContextAddress_ == address(0) ? msg.sender : currentContextAddress_;
return contextAddress;
}
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
index 86194f461..a5459a21e 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
@@ -19,18 +19,22 @@
pragma solidity 0.4.24;
pragma experimental ABIEncoderV2;
+import "../../utils/ReentrancyGuard/ReentrancyGuard.sol";
import "./libs/LibMath.sol";
import "./libs/LibOrder.sol";
import "./libs/LibFillResults.sol";
import "./libs/LibAbiEncoder.sol";
import "./mixins/MExchangeCore.sol";
+import "./mixins/MWrapperFunctions.sol";
contract MixinWrapperFunctions is
+ ReentrancyGuard,
LibMath,
LibFillResults,
LibAbiEncoder,
- MExchangeCore
+ MExchangeCore,
+ MWrapperFunctions
{
/// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
@@ -43,17 +47,14 @@ contract MixinWrapperFunctions is
bytes memory signature
)
public
+ nonReentrant
returns (FillResults memory fillResults)
{
- fillResults = fillOrder(
+ fillResults = fillOrKillOrderInternal(
order,
takerAssetFillAmount,
signature
);
- require(
- fillResults.takerAssetFilledAmount == takerAssetFillAmount,
- "COMPLETE_FILL_FAILED"
- );
return fillResults;
}
@@ -88,20 +89,14 @@ contract MixinWrapperFunctions is
fillOrderCalldata, // write output over input
128 // output size is 128 bytes
)
- switch success
- case 0 {
- mstore(fillResults, 0)
- mstore(add(fillResults, 32), 0)
- mstore(add(fillResults, 64), 0)
- mstore(add(fillResults, 96), 0)
- }
- case 1 {
+ if success {
mstore(fillResults, mload(fillOrderCalldata))
mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32)))
mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64)))
mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96)))
}
}
+ // fillResults values will be 0 by default if call was unsuccessful
return fillResults;
}
@@ -117,11 +112,12 @@ contract MixinWrapperFunctions is
bytes[] memory signatures
)
public
+ nonReentrant
returns (FillResults memory totalFillResults)
{
uint256 ordersLength = orders.length;
for (uint256 i = 0; i != ordersLength; i++) {
- FillResults memory singleFillResults = fillOrder(
+ FillResults memory singleFillResults = fillOrderInternal(
orders[i],
takerAssetFillAmounts[i],
signatures[i]
@@ -143,11 +139,12 @@ contract MixinWrapperFunctions is
bytes[] memory signatures
)
public
+ nonReentrant
returns (FillResults memory totalFillResults)
{
uint256 ordersLength = orders.length;
for (uint256 i = 0; i != ordersLength; i++) {
- FillResults memory singleFillResults = fillOrKillOrder(
+ FillResults memory singleFillResults = fillOrKillOrderInternal(
orders[i],
takerAssetFillAmounts[i],
signatures[i]
@@ -195,6 +192,7 @@ contract MixinWrapperFunctions is
bytes[] memory signatures
)
public
+ nonReentrant
returns (FillResults memory totalFillResults)
{
bytes memory takerAssetData = orders[0].takerAssetData;
@@ -210,7 +208,7 @@ contract MixinWrapperFunctions is
uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
// Attempt to sell the remaining amount of takerAsset
- FillResults memory singleFillResults = fillOrder(
+ FillResults memory singleFillResults = fillOrderInternal(
orders[i],
remainingTakerAssetFillAmount,
signatures[i]
@@ -282,6 +280,7 @@ contract MixinWrapperFunctions is
bytes[] memory signatures
)
public
+ nonReentrant
returns (FillResults memory totalFillResults)
{
bytes memory makerAssetData = orders[0].makerAssetData;
@@ -298,14 +297,14 @@ contract MixinWrapperFunctions is
// Convert the remaining amount of makerAsset to buy into remaining amount
// of takerAsset to sell, assuming entire amount can be sold in the current order
- uint256 remainingTakerAssetFillAmount = getPartialAmount(
+ uint256 remainingTakerAssetFillAmount = getPartialAmountFloor(
orders[i].takerAssetAmount,
orders[i].makerAssetAmount,
remainingMakerAssetFillAmount
);
// Attempt to sell the remaining amount of takerAsset
- FillResults memory singleFillResults = fillOrder(
+ FillResults memory singleFillResults = fillOrderInternal(
orders[i],
remainingTakerAssetFillAmount,
signatures[i]
@@ -350,7 +349,7 @@ contract MixinWrapperFunctions is
// Convert the remaining amount of makerAsset to buy into remaining amount
// of takerAsset to sell, assuming entire amount can be sold in the current order
- uint256 remainingTakerAssetFillAmount = getPartialAmount(
+ uint256 remainingTakerAssetFillAmount = getPartialAmountFloor(
orders[i].takerAssetAmount,
orders[i].makerAssetAmount,
remainingMakerAssetFillAmount
@@ -400,4 +399,28 @@ contract MixinWrapperFunctions is
}
return ordersInfo;
}
+
+ /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
+ /// @param order Order struct containing order specifications.
+ /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+ /// @param signature Proof that order has been created by maker.
+ function fillOrKillOrderInternal(
+ LibOrder.Order memory order,
+ uint256 takerAssetFillAmount,
+ bytes memory signature
+ )
+ internal
+ returns (FillResults memory fillResults)
+ {
+ fillResults = fillOrderInternal(
+ order,
+ takerAssetFillAmount,
+ signature
+ );
+ require(
+ fillResults.takerAssetFilledAmount == takerAssetFillAmount,
+ "COMPLETE_FILL_FAILED"
+ );
+ return fillResults;
+ }
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
index fa09da6ac..57fd53f29 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
@@ -25,12 +25,13 @@ contract LibMath is
SafeMath
{
- /// @dev Calculates partial value given a numerator and denominator.
+ /// @dev Calculates partial value given a numerator and denominator rounded down.
+ /// Reverts if rounding error is >= 0.1%
/// @param numerator Numerator.
/// @param denominator Denominator.
/// @param target Value to calculate partial of.
- /// @return Partial value of target.
- function getPartialAmount(
+ /// @return Partial value of target rounded down.
+ function safeGetPartialAmountFloor(
uint256 numerator,
uint256 denominator,
uint256 target
@@ -39,19 +40,133 @@ contract LibMath is
pure
returns (uint256 partialAmount)
{
+ require(
+ denominator > 0,
+ "DIVISION_BY_ZERO"
+ );
+
+ require(
+ !isRoundingErrorFloor(
+ numerator,
+ denominator,
+ target
+ ),
+ "ROUNDING_ERROR"
+ );
+
+ partialAmount = safeDiv(
+ safeMul(numerator, target),
+ denominator
+ );
+ return partialAmount;
+ }
+
+ /// @dev Calculates partial value given a numerator and denominator rounded down.
+ /// Reverts if rounding error is >= 0.1%
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to calculate partial of.
+ /// @return Partial value of target rounded up.
+ function safeGetPartialAmountCeil(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ internal
+ pure
+ returns (uint256 partialAmount)
+ {
+ require(
+ denominator > 0,
+ "DIVISION_BY_ZERO"
+ );
+
+ require(
+ !isRoundingErrorCeil(
+ numerator,
+ denominator,
+ target
+ ),
+ "ROUNDING_ERROR"
+ );
+
+ // safeDiv computes `floor(a / b)`. We use the identity (a, b integer):
+ // ceil(a / b) = floor((a + b - 1) / b)
+ // To implement `ceil(a / b)` using safeDiv.
+ partialAmount = safeDiv(
+ safeAdd(
+ safeMul(numerator, target),
+ safeSub(denominator, 1)
+ ),
+ denominator
+ );
+ return partialAmount;
+ }
+
+ /// @dev Calculates partial value given a numerator and denominator rounded down.
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to calculate partial of.
+ /// @return Partial value of target rounded down.
+ function getPartialAmountFloor(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ internal
+ pure
+ returns (uint256 partialAmount)
+ {
+ require(
+ denominator > 0,
+ "DIVISION_BY_ZERO"
+ );
+
partialAmount = safeDiv(
safeMul(numerator, target),
denominator
);
return partialAmount;
}
+
+ /// @dev Calculates partial value given a numerator and denominator rounded down.
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to calculate partial of.
+ /// @return Partial value of target rounded up.
+ function getPartialAmountCeil(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ internal
+ pure
+ returns (uint256 partialAmount)
+ {
+ require(
+ denominator > 0,
+ "DIVISION_BY_ZERO"
+ );
- /// @dev Checks if rounding error > 0.1%.
+ // safeDiv computes `floor(a / b)`. We use the identity (a, b integer):
+ // ceil(a / b) = floor((a + b - 1) / b)
+ // To implement `ceil(a / b)` using safeDiv.
+ partialAmount = safeDiv(
+ safeAdd(
+ safeMul(numerator, target),
+ safeSub(denominator, 1)
+ ),
+ denominator
+ );
+ return partialAmount;
+ }
+
+ /// @dev Checks if rounding error >= 0.1% when rounding down.
/// @param numerator Numerator.
/// @param denominator Denominator.
/// @param target Value to multiply with numerator/denominator.
/// @return Rounding error is present.
- function isRoundingError(
+ function isRoundingErrorFloor(
uint256 numerator,
uint256 denominator,
uint256 target
@@ -60,16 +175,73 @@ contract LibMath is
pure
returns (bool isError)
{
- uint256 remainder = mulmod(target, numerator, denominator);
- if (remainder == 0) {
- return false; // No rounding error.
+ require(
+ denominator > 0,
+ "DIVISION_BY_ZERO"
+ );
+
+ // The absolute rounding error is the difference between the rounded
+ // value and the ideal value. The relative rounding error is the
+ // absolute rounding error divided by the absolute value of the
+ // ideal value. This is undefined when the ideal value is zero.
+ //
+ // The ideal value is `numerator * target / denominator`.
+ // Let's call `numerator * target % denominator` the remainder.
+ // The absolute error is `remainder / denominator`.
+ //
+ // When the ideal value is zero, we require the absolute error to
+ // be zero. Fortunately, this is always the case. The ideal value is
+ // zero iff `numerator == 0` and/or `target == 0`. In this case the
+ // remainder and absolute error are also zero.
+ if (target == 0 || numerator == 0) {
+ return false;
}
-
- uint256 errPercentageTimes1000000 = safeDiv(
- safeMul(remainder, 1000000),
- safeMul(numerator, target)
+
+ // Otherwise, we want the relative rounding error to be strictly
+ // less than 0.1%.
+ // The relative error is `remainder / (numerator * target)`.
+ // We want the relative error less than 1 / 1000:
+ // remainder / (numerator * denominator) < 1 / 1000
+ // or equivalently:
+ // 1000 * remainder < numerator * target
+ // so we have a rounding error iff:
+ // 1000 * remainder >= numerator * target
+ uint256 remainder = mulmod(target, numerator, denominator);
+ isError = safeMul(1000, remainder) >= safeMul(numerator, target);
+ return isError;
+ }
+
+ /// @dev Checks if rounding error >= 0.1% when rounding up.
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to multiply with numerator/denominator.
+ /// @return Rounding error is present.
+ function isRoundingErrorCeil(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ internal
+ pure
+ returns (bool isError)
+ {
+ require(
+ denominator > 0,
+ "DIVISION_BY_ZERO"
);
- isError = errPercentageTimes1000000 > 1000;
+
+ // See the comments in `isRoundingError`.
+ if (target == 0 || numerator == 0) {
+ // When either is zero, the ideal value and rounded value are zero
+ // and there is no rounding error. (Although the relative error
+ // is undefined.)
+ return false;
+ }
+ // Compute remainder as before
+ uint256 remainder = mulmod(target, numerator, denominator);
+ // TODO: safeMod
+ remainder = safeSub(denominator, remainder) % denominator;
+ isError = safeMul(1000, remainder) >= safeMul(numerator, target);
return isError;
}
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
index c165b647c..d85913e0f 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
@@ -59,6 +59,19 @@ contract MExchangeCore is
uint256 orderEpoch // Orders with specified makerAddress and senderAddress with a salt less than this value are considered cancelled.
);
+ /// @dev Fills the input order.
+ /// @param order Order struct containing order specifications.
+ /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+ /// @param signature Proof that order has been created by maker.
+ /// @return Amounts filled and fees paid by maker and taker.
+ function fillOrderInternal(
+ LibOrder.Order memory order,
+ uint256 takerAssetFillAmount,
+ bytes memory signature
+ )
+ internal
+ returns (LibFillResults.FillResults memory fillResults);
+
/// @dev Updates state with results of a fill order.
/// @param order that was filled.
/// @param takerAddress Address of taker who filled the order.
@@ -83,21 +96,33 @@ contract MExchangeCore is
bytes32 orderHash
)
internal;
-
+
/// @dev Validates context for fillOrder. Succeeds or throws.
/// @param order to be filled.
- /// @param orderInfo Status, orderHash, and amount already filled of order.
+ /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
/// @param takerAddress Address of order taker.
+ /// @param signature Proof that the orders was created by its maker.
+ function assertFillableOrder(
+ LibOrder.Order memory order,
+ LibOrder.OrderInfo memory orderInfo,
+ address takerAddress,
+ bytes memory signature
+ )
+ internal
+ view;
+
+ /// @dev Validates context for fillOrder. Succeeds or throws.
+ /// @param order to be filled.
+ /// @param orderInfo Status, orderHash, and amount already filled of order.
/// @param takerAssetFillAmount Desired amount of order to fill by taker.
/// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
- /// @param signature Proof that the orders was created by its maker.
+ /// @param makerAssetFilledAmount Amount of makerAsset that will be transfered.
function assertValidFill(
LibOrder.Order memory order,
LibOrder.OrderInfo memory orderInfo,
- address takerAddress,
uint256 takerAssetFillAmount,
uint256 takerAssetFilledAmount,
- bytes memory signature
+ uint256 makerAssetFilledAmount
)
internal
view;
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
index f14f2ba00..1fe88b908 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
@@ -36,11 +36,40 @@ contract MSignatureValidator is
Invalid, // 0x01
EIP712, // 0x02
EthSign, // 0x03
- Caller, // 0x04
- Wallet, // 0x05
- Validator, // 0x06
- PreSigned, // 0x07
- Trezor, // 0x08
- NSignatureTypes // 0x09, number of signature types. Always leave at end.
+ Wallet, // 0x04
+ Validator, // 0x05
+ PreSigned, // 0x06
+ NSignatureTypes // 0x07, number of signature types. Always leave at end.
}
+
+ /// @dev Verifies signature using logic defined by Wallet contract.
+ /// @param hash Any 32 byte hash.
+ /// @param walletAddress Address that should have signed the given hash
+ /// and defines its own signature verification method.
+ /// @param signature Proof that the hash has been signed by signer.
+ /// @return True if the address recovered from the provided signature matches the input signer address.
+ function isValidWalletSignature(
+ bytes32 hash,
+ address walletAddress,
+ bytes signature
+ )
+ internal
+ view
+ returns (bool isValid);
+
+ /// @dev Verifies signature using logic defined by Validator contract.
+ /// @param validatorAddress Address of validator contract.
+ /// @param hash Any 32 byte hash.
+ /// @param signerAddress Address that should have signed the given hash.
+ /// @param signature Proof that the hash has been signed by signer.
+ /// @return True if the address recovered from the provided signature matches the input signer address.
+ function isValidValidatorSignature(
+ address validatorAddress,
+ bytes32 hash,
+ address signerAddress,
+ bytes signature
+ )
+ internal
+ view
+ returns (bool isValid);
}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MWrapperFunctions.sol
new file mode 100644
index 000000000..e04d4a429
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MWrapperFunctions.sol
@@ -0,0 +1,40 @@
+/*
+
+ Copyright 2018 ZeroEx Intl.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
+import "../interfaces/IWrapperFunctions.sol";
+
+
+contract MWrapperFunctions {
+
+ /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
+ /// @param order LibOrder.Order struct containing order specifications.
+ /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+ /// @param signature Proof that order has been created by maker.
+ function fillOrKillOrderInternal(
+ LibOrder.Order memory order,
+ uint256 takerAssetFillAmount,
+ bytes memory signature
+ )
+ internal
+ returns (LibFillResults.FillResults memory fillResults);
+}
diff --git a/packages/contracts/src/2.0.0/test/ReentrantERC20Token/ReentrantERC20Token.sol b/packages/contracts/src/2.0.0/test/ReentrantERC20Token/ReentrantERC20Token.sol
new file mode 100644
index 000000000..4f4e28302
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/ReentrantERC20Token/ReentrantERC20Token.sol
@@ -0,0 +1,183 @@
+/*
+
+ Copyright 2018 ZeroEx Intl.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "../../tokens/ERC20Token/ERC20Token.sol";
+import "../../protocol/Exchange/interfaces/IExchange.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+
+
+// solhint-disable no-unused-vars
+contract ReentrantERC20Token is
+ ERC20Token
+{
+
+ using LibBytes for bytes;
+
+ // solhint-disable-next-line var-name-mixedcase
+ IExchange internal EXCHANGE;
+
+ bytes internal constant REENTRANCY_ILLEGAL_REVERT_REASON = abi.encodeWithSelector(
+ bytes4(keccak256("Error(string)")),
+ "REENTRANCY_ILLEGAL"
+ );
+
+ // All of these functions are potentially vulnerable to reentrancy
+ // We do not test any "noThrow" functions because `fillOrderNoThrow` makes a delegatecall to `fillOrder`
+ enum ExchangeFunction {
+ FILL_ORDER,
+ FILL_OR_KILL_ORDER,
+ BATCH_FILL_ORDERS,
+ BATCH_FILL_OR_KILL_ORDERS,
+ MARKET_BUY_ORDERS,
+ MARKET_SELL_ORDERS,
+ MATCH_ORDERS,
+ CANCEL_ORDER,
+ CANCEL_ORDERS_UP_TO,
+ SET_SIGNATURE_VALIDATOR_APPROVAL
+ }
+
+ uint8 internal currentFunctionId = 0;
+
+ constructor (address _exchange)
+ public
+ {
+ EXCHANGE = IExchange(_exchange);
+ }
+
+ /// @dev Set the current function that will be called when `transferFrom` is called.
+ /// @param _currentFunctionId Id that corresponds to function name.
+ function setCurrentFunction(uint8 _currentFunctionId)
+ external
+ {
+ currentFunctionId = _currentFunctionId;
+ }
+
+ /// @dev A version of `transferFrom` that attempts to reenter the Exchange contract.
+ /// @param _from The address of the sender
+ /// @param _to The address of the recipient
+ /// @param _value The amount of token to be transferred
+ function transferFrom(
+ address _from,
+ address _to,
+ uint256 _value
+ )
+ external
+ returns (bool)
+ {
+ // This order would normally be invalid, but it will be used strictly for testing reentrnacy.
+ // Any reentrancy checks will happen before any other checks that invalidate the order.
+ LibOrder.Order memory order;
+
+ // Initialize remaining null parameters
+ bytes memory signature;
+ LibOrder.Order[] memory orders;
+ uint256[] memory takerAssetFillAmounts;
+ bytes[] memory signatures;
+ bytes memory calldata;
+
+ // Create calldata for function that corresponds to currentFunctionId
+ if (currentFunctionId == uint8(ExchangeFunction.FILL_ORDER)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.fillOrder.selector,
+ order,
+ 0,
+ signature
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.FILL_OR_KILL_ORDER)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.fillOrKillOrder.selector,
+ order,
+ 0,
+ signature
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.BATCH_FILL_ORDERS)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.batchFillOrders.selector,
+ orders,
+ takerAssetFillAmounts,
+ signatures
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.BATCH_FILL_OR_KILL_ORDERS)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.batchFillOrKillOrders.selector,
+ orders,
+ takerAssetFillAmounts,
+ signatures
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.MARKET_BUY_ORDERS)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.marketBuyOrders.selector,
+ orders,
+ 0,
+ signatures
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.MARKET_SELL_ORDERS)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.marketSellOrders.selector,
+ orders,
+ 0,
+ signatures
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.MATCH_ORDERS)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.matchOrders.selector,
+ order,
+ order,
+ signature,
+ signature
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.CANCEL_ORDER)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.cancelOrder.selector,
+ order
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.CANCEL_ORDERS_UP_TO)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.cancelOrdersUpTo.selector,
+ 0
+ );
+ } else if (currentFunctionId == uint8(ExchangeFunction.SET_SIGNATURE_VALIDATOR_APPROVAL)) {
+ calldata = abi.encodeWithSelector(
+ EXCHANGE.setSignatureValidatorApproval.selector,
+ address(0),
+ false
+ );
+ }
+
+ // Call Exchange function, swallow error
+ address(EXCHANGE).call(calldata);
+
+ // Revert reason is 100 bytes
+ bytes memory returnData = new bytes(100);
+
+ // Copy return data
+ assembly {
+ returndatacopy(add(returnData, 32), 0, 100)
+ }
+
+ // Revert if function reverted with REENTRANCY_ILLEGAL error
+ require(!REENTRANCY_ILLEGAL_REVERT_REASON.equals(returnData));
+
+ // Transfer will return true if function failed for any other reason
+ return true;
+ }
+} \ No newline at end of file
diff --git a/packages/contracts/src/2.0.0/test/TestExchangeInternals/TestExchangeInternals.sol b/packages/contracts/src/2.0.0/test/TestExchangeInternals/TestExchangeInternals.sol
index d9cec9edc..27187f8f8 100644
--- a/packages/contracts/src/2.0.0/test/TestExchangeInternals/TestExchangeInternals.sol
+++ b/packages/contracts/src/2.0.0/test/TestExchangeInternals/TestExchangeInternals.sol
@@ -63,11 +63,12 @@ contract TestExchangeInternals is
}
/// @dev Calculates partial value given a numerator and denominator.
+ /// Reverts if rounding error is >= 0.1%
/// @param numerator Numerator.
/// @param denominator Denominator.
/// @param target Value to calculate partial of.
/// @return Partial value of target.
- function publicGetPartialAmount(
+ function publicSafeGetPartialAmountFloor(
uint256 numerator,
uint256 denominator,
uint256 target
@@ -76,15 +77,84 @@ contract TestExchangeInternals is
pure
returns (uint256 partialAmount)
{
- return getPartialAmount(numerator, denominator, target);
+ return safeGetPartialAmountFloor(numerator, denominator, target);
}
- /// @dev Checks if rounding error > 0.1%.
+ /// @dev Calculates partial value given a numerator and denominator.
+ /// Reverts if rounding error is >= 0.1%
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to calculate partial of.
+ /// @return Partial value of target.
+ function publicSafeGetPartialAmountCeil(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ public
+ pure
+ returns (uint256 partialAmount)
+ {
+ return safeGetPartialAmountCeil(numerator, denominator, target);
+ }
+
+ /// @dev Calculates partial value given a numerator and denominator.
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to calculate partial of.
+ /// @return Partial value of target.
+ function publicGetPartialAmountFloor(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ public
+ pure
+ returns (uint256 partialAmount)
+ {
+ return getPartialAmountFloor(numerator, denominator, target);
+ }
+
+ /// @dev Calculates partial value given a numerator and denominator.
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to calculate partial of.
+ /// @return Partial value of target.
+ function publicGetPartialAmountCeil(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ public
+ pure
+ returns (uint256 partialAmount)
+ {
+ return getPartialAmountCeil(numerator, denominator, target);
+ }
+
+ /// @dev Checks if rounding error >= 0.1%.
+ /// @param numerator Numerator.
+ /// @param denominator Denominator.
+ /// @param target Value to multiply with numerator/denominator.
+ /// @return Rounding error is present.
+ function publicIsRoundingErrorFloor(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ public
+ pure
+ returns (bool isError)
+ {
+ return isRoundingErrorFloor(numerator, denominator, target);
+ }
+
+ /// @dev Checks if rounding error >= 0.1%.
/// @param numerator Numerator.
/// @param denominator Denominator.
/// @param target Value to multiply with numerator/denominator.
/// @return Rounding error is present.
- function publicIsRoundingError(
+ function publicIsRoundingErrorCeil(
uint256 numerator,
uint256 denominator,
uint256 target
@@ -93,7 +163,7 @@ contract TestExchangeInternals is
pure
returns (bool isError)
{
- return isRoundingError(numerator, denominator, target);
+ return isRoundingErrorCeil(numerator, denominator, target);
}
/// @dev Updates state with results of a fill order.
diff --git a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
index 4a99dd9c1..c8c58545f 100644
--- a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
+++ b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
@@ -49,7 +49,7 @@ contract TestLibs is
return fillOrderCalldata;
}
- function publicGetPartialAmount(
+ function publicGetPartialAmountFloor(
uint256 numerator,
uint256 denominator,
uint256 target
@@ -58,7 +58,7 @@ contract TestLibs is
pure
returns (uint256 partialAmount)
{
- partialAmount = getPartialAmount(
+ partialAmount = getPartialAmountFloor(
numerator,
denominator,
target
@@ -66,7 +66,41 @@ contract TestLibs is
return partialAmount;
}
- function publicIsRoundingError(
+ function publicGetPartialAmountCeil(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ public
+ pure
+ returns (uint256 partialAmount)
+ {
+ partialAmount = getPartialAmountCeil(
+ numerator,
+ denominator,
+ target
+ );
+ return partialAmount;
+ }
+
+ function publicIsRoundingErrorFloor(
+ uint256 numerator,
+ uint256 denominator,
+ uint256 target
+ )
+ public
+ pure
+ returns (bool isError)
+ {
+ isError = isRoundingErrorFloor(
+ numerator,
+ denominator,
+ target
+ );
+ return isError;
+ }
+
+ function publicIsRoundingErrorCeil(
uint256 numerator,
uint256 denominator,
uint256 target
@@ -75,7 +109,7 @@ contract TestLibs is
pure
returns (bool isError)
{
- isError = isRoundingError(
+ isError = isRoundingErrorCeil(
numerator,
denominator,
target
diff --git a/packages/contracts/src/2.0.0/test/TestStaticCallReceiver/TestStaticCallReceiver.sol b/packages/contracts/src/2.0.0/test/TestStaticCallReceiver/TestStaticCallReceiver.sol
new file mode 100644
index 000000000..41aab01c8
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestStaticCallReceiver/TestStaticCallReceiver.sol
@@ -0,0 +1,81 @@
+/*
+
+ Copyright 2018 ZeroEx Intl.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+
+import "../../tokens/ERC20Token/IERC20Token.sol";
+
+
+// solhint-disable no-unused-vars
+contract TestStaticCallReceiver {
+
+ uint256 internal state = 1;
+
+ /// @dev Updates state and returns true. Intended to be used with `Validator` signature type.
+ /// @param hash Message hash that is signed.
+ /// @param signerAddress Address that should have signed the given hash.
+ /// @param signature Proof of signing.
+ /// @return Validity of order signature.
+ function isValidSignature(
+ bytes32 hash,
+ address signerAddress,
+ bytes signature
+ )
+ external
+ returns (bool isValid)
+ {
+ updateState();
+ return true;
+ }
+
+ /// @dev Updates state and returns true. Intended to be used with `Wallet` signature type.
+ /// @param hash Message hash that is signed.
+ /// @param signature Proof of signing.
+ /// @return Validity of order signature.
+ function isValidSignature(
+ bytes32 hash,
+ bytes signature
+ )
+ external
+ returns (bool isValid)
+ {
+ updateState();
+ return true;
+ }
+
+ /// @dev Approves an ERC20 token to spend tokens from this address.
+ /// @param token Address of ERC20 token.
+ /// @param spender Address that will spend tokens.
+ /// @param value Amount of tokens spender is approved to spend.
+ function approveERC20(
+ address token,
+ address spender,
+ uint256 value
+ )
+ external
+ {
+ IERC20Token(token).approve(spender, value);
+ }
+
+ /// @dev Increments state variable.
+ function updateState()
+ internal
+ {
+ state++;
+ }
+}
diff --git a/packages/contracts/src/2.0.0/utils/ReentrancyGuard/ReentrancyGuard.sol b/packages/contracts/src/2.0.0/utils/ReentrancyGuard/ReentrancyGuard.sol
new file mode 100644
index 000000000..1dee512d4
--- /dev/null
+++ b/packages/contracts/src/2.0.0/utils/ReentrancyGuard/ReentrancyGuard.sol
@@ -0,0 +1,44 @@
+/*
+
+ Copyright 2018 ZeroEx Intl.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+*/
+pragma solidity 0.4.24;
+
+
+contract ReentrancyGuard {
+
+ // Locked state of mutex
+ bool private locked = false;
+
+ /// @dev Functions with this modifer cannot be reentered. The mutex will be locked
+ /// before function execution and unlocked after.
+ modifier nonReentrant() {
+ // Ensure mutex is unlocked
+ require(
+ !locked,
+ "REENTRANCY_ILLEGAL"
+ );
+
+ // Lock mutex before function call
+ locked = true;
+
+ // Perform function call
+ _;
+
+ // Unlock mutex after function call
+ locked = false;
+ }
+}