ETH+/ETH collateral feedback (#1141)

Co-authored-by: Julian M. Rodriguez <[email protected]>

contracts/plugins/assets/curve/CurveAppreciatingRTokenFiatCollateral.sol

@@ -87,9 +87,16 @@ contract CurveAppreciatingRTokenFiatCollateral is CurveStableCollateral {
                     assert(low == 0);
                 }
 
-                // Check RToken status
+                // Check pool status: inner RToken must be both isReady() and
+                // fullyCollateralized() to prevent injection of bad debt.
                 try pairedBasketHandler.isReady() returns (bool isReady) {
-                    if (!isReady || low == 0 || _anyDepeggedInPool() || _anyDepeggedOutsidePool()) {
+                    if (
+                        !isReady ||
+                        low == 0 ||
+                        _anyDepeggedInPool() ||
+                        _anyDepeggedOutsidePool() ||
+                        !pairedBasketHandler.fullyCollateralized()
+                    ) {
                         // If the price is below the default-threshold price, default eventually
                         // uint192(+/-) is the same as Fix.plus/minus
                         markStatus(CollateralStatus.IFFY);
@@ -119,6 +126,7 @@ contract CurveAppreciatingRTokenFiatCollateral is CurveStableCollateral {
     }
 
     /// @dev Not up-only! The RToken can devalue its exchange rate peg
+    /// @dev Assumption: The RToken BU is intended to equal the reference token in value
     /// @return {ref/tok} Quantity of whole reference units per whole collateral tokens
     function underlyingRefPerTok() public view virtual override returns (uint192) {
         // {ref/tok} = quantity of the reference unit token in the pool per LP token
@@ -154,34 +162,13 @@ contract CurveAppreciatingRTokenFiatCollateral is CurveStableCollateral {
     function _anyDepeggedInPool() internal view virtual override returns (bool) {
         // Assumption: token0 is the RToken; token1 is the reference token
 
-        // Check RToken price against reference token, accounting for appreciation
-        try this.tokenPrice(0) returns (uint192 low0, uint192 high0) {
-            // {UoA/tok} = {UoA/tok} + {UoA/tok}
-            uint192 mid0 = (low0 + high0) / 2;
+        // Check reference token price
+        try this.tokenPrice(1) returns (uint192 low1, uint192 high1) {
+            // {target/ref} = {UoA/ref} = {UoA/ref} + {UoA/ref}
+            uint192 mid1 = (low1 + high1) / 2;
 
-            // Remove the appreciation portion of the RToken price
-            // {UoA/ref} = {UoA/tok} * {tok} / {ref}
-            mid0 = mid0.muluDivu(rToken.totalSupply(), rToken.basketsNeeded());
-
-            try this.tokenPrice(1) returns (uint192 low1, uint192 high1) {
-                // {target/ref} = {UoA/ref} = {UoA/ref} + {UoA/ref}
-                uint192 mid1 = (low1 + high1) / 2;
-
-                // Check price of reference token
-                if (mid1 < pegBottom || mid1 > pegTop) return true;
-
-                // {target/ref} = {UoA/ref} / {UoA/ref} * {target/ref}
-                uint192 ratio = mid0.div(mid1); // * targetPerRef(), but we know it's 1
-
-                // Check price of RToken relative to reference token
-                if (ratio < pegBottom || ratio > pegTop) return true;
-            } catch (bytes memory errData) {
-                // see: docs/solidity-style.md#Catching-Empty-Data
-                // untested:
-                //      pattern validated in other plugins, cost to test is high
-                if (errData.length == 0) revert(); // solhint-disable-line reason-string
-                return true;
-            }
+            // Check price of reference token
+            if (mid1 < pegBottom || mid1 > pegTop) return true;
         } catch (bytes memory errData) {
             // see: docs/solidity-style.md#Catching-Empty-Data
             // untested:
@@ -190,6 +177,8 @@ contract CurveAppreciatingRTokenFiatCollateral is CurveStableCollateral {
             return true;
         }
 
+        // The RToken does not need to be monitored given more restrictive hard-default checks
+
         return false;
     }
 }

contracts/plugins/assets/curve/CurveAppreciatingRTokenSelfReferentialCollateral.sol

@@ -19,8 +19,9 @@ import "./CurveAppreciatingRTokenFiatCollateral.sol";
  * tar = ETH
  * UoA = USD
  *
- * @notice Curve pools with native ETH or ERC777 should be avoided,
- *  see docs/collateral.md for information
+ * @notice This Curve Pool contains WETH, which can be used to intercept execution by providing
+ *         `use_eth=true` to remove_liquidity()/remove_liquidity_one_coin(). It is guarded against
+ *          by the recommended method of calling `claim_admin_fees()`.
  */
 contract CurveAppreciatingRTokenSelfReferentialCollateral is CurveAppreciatingRTokenFiatCollateral {
     using OracleLib for AggregatorV3Interface;
@@ -36,46 +37,18 @@ contract CurveAppreciatingRTokenSelfReferentialCollateral is CurveAppreciatingRT
         PTConfiguration memory ptConfig
     ) CurveAppreciatingRTokenFiatCollateral(config, revenueHiding, ptConfig) {}
 
-    // solhint-enable no-empty-blocks
+    /// Should not revert (unless CurvePool is re-entrant!)
+    /// Refresh exchange rates and update default status.
+    function refresh() public virtual override {
+        curvePool.claim_admin_fees(); // revert if curve pool is re-entrant
+        super.refresh();
+    }
 
     // === Internal ===
 
     function _anyDepeggedInPool() internal view virtual override returns (bool) {
-        // Assumption: token0 is the RToken; token1 is the reference token
-
-        // Check RToken price against reference token, accounting for appreciation
-        try this.tokenPrice(0) returns (uint192 low0, uint192 high0) {
-            // {UoA/tok} = {UoA/tok} + {UoA/tok}
-            uint192 mid0 = (low0 + high0) / 2;
-
-            // Remove the appreciation portion of the RToken price
-            // {UoA/ref} = {UoA/tok} * {tok} / {ref}
-            mid0 = mid0.muluDivu(rToken.totalSupply(), rToken.basketsNeeded());
-
-            try this.tokenPrice(1) returns (uint192 low1, uint192 high1) {
-                // {UoA/ref} = {UoA/ref} + {UoA/ref}
-                uint192 mid1 = (low1 + high1) / 2;
-
-                // {target/ref} = {UoA/ref} / {UoA/ref} * {target/ref}
-                uint192 ratio = mid0.div(mid1); // * targetPerRef(), but we know it's 1
-
-                // Check price of RToken relative to reference token
-                if (ratio < pegBottom || ratio > pegTop) return true;
-            } catch (bytes memory errData) {
-                // see: docs/solidity-style.md#Catching-Empty-Data
-                // untested:
-                //      pattern validated in other plugins, cost to test is high
-                if (errData.length == 0) revert(); // solhint-disable-line reason-string
-                return true;
-            }
-        } catch (bytes memory errData) {
-            // see: docs/solidity-style.md#Catching-Empty-Data
-            // untested:
-            //      pattern validated in other plugins, cost to test is high
-            if (errData.length == 0) revert(); // solhint-disable-line reason-string
-            return true;
-        }
-
+        // WETH cannot de-peg against ETH (the price feed we have is ETH/USD)
+        // The RToken does not need to be monitored given more restrictive hard-default checks
         return false;
     }
 }

contracts/plugins/assets/curve/CurveRecursiveCollateral.sol

@@ -18,6 +18,8 @@ import "../OracleLib.sol";
  *      - The RToken _must_ be the same RToken using this plugin as collateral!
  *      - The RToken SHOULD have an RSR overcollateralization layer. DO NOT USE WITHOUT RSR!
  *      - The LP token should be worth ~2x the reference token. Do not use with 1x lpTokens.
+ *      - Lastly: Do NOT deploy an RToken with this collateral! It can only be swapped
+ *                in at a later date once the RToken has nonzero issuance.
  *
  * tok = ConvexStakingWrapper or CurveGaugeWrapper
  * ref = coins(0) in the pool
@@ -30,6 +32,9 @@ contract CurveRecursiveCollateral is CurveStableCollateral {
 
     IRToken internal immutable rToken; // token1
 
+    // does not become nonzero until after first refresh()
+    uint192 internal poolVirtualPrice; // {lpToken@t=0/lpToken} max virtual price sub revenue hiding
+
     /// @param config.erc20 must be of type ConvexStakingWrapper or CurveGaugeWrapper
     /// @param config.chainlinkFeed Feed units: {UoA/ref}
     constructor(
@@ -38,9 +43,6 @@ contract CurveRecursiveCollateral is CurveStableCollateral {
         PTConfiguration memory ptConfig
     ) CurveStableCollateral(config, revenueHiding, ptConfig) {
         rToken = IRToken(address(token1));
-
-        // {ref/tok} LP token's virtual price
-        exposedReferencePrice = _safeWrap(curvePool.get_virtual_price()).mul(revenueShowing);
     }
 
     /// Can revert, used by other contract functions in order to catch errors
@@ -83,25 +85,42 @@ contract CurveRecursiveCollateral is CurveStableCollateral {
     function refresh() public virtual override {
         CollateralStatus oldStatus = status();
 
-        try this.underlyingRefPerTok() returns (uint192) {
+        try this.underlyingRefPerTok() returns (uint192 underlyingRefPerTok_) {
             // Instead of ensuring the underlyingRefPerTok is up-only, solely check
             // that the pool's virtual price is up-only. Otherwise this collateral
-            // would create default cascades.
+            // would create default cascades when basketsNeeded()/totalSupply() falls.
+
+            // === Check for virtualPrice hard default ===
 
-            // {ref/tok}
+            // {lpToken@t=0/lpToken}
             uint192 virtualPrice = _safeWrap(curvePool.get_virtual_price());
 
-            // {ref/tok} = {ref/tok} * {1}
-            uint192 hiddenReferencePrice = virtualPrice.mul(revenueShowing);
+            // {lpToken@t=0/lpToken}
+            uint192 hiddenVirtualPrice = virtualPrice.mul(revenueShowing);
 
             // uint192(<) is equivalent to Fix.lt
-            if (virtualPrice < exposedReferencePrice) {
-                exposedReferencePrice = virtualPrice;
+            if (virtualPrice < poolVirtualPrice) {
+                poolVirtualPrice = virtualPrice;
                 markStatus(CollateralStatus.DISABLED);
+            } else if (hiddenVirtualPrice > poolVirtualPrice) {
+                poolVirtualPrice = hiddenVirtualPrice;
+            }
+
+            // === Update exposedReferencePrice, ignoring default ===
+
+            // {ref/tok} = {ref/tok} * {1}
+            uint192 hiddenReferencePrice = underlyingRefPerTok_.mul(revenueShowing);
+
+            // uint192(<) is equivalent to Fix.lt
+            if (underlyingRefPerTok_ < exposedReferencePrice) {
+                exposedReferencePrice = underlyingRefPerTok_;
+                // markStatus(CollateralStatus.DISABLED); // don't DISABLE
             } else if (hiddenReferencePrice > exposedReferencePrice) {
                 exposedReferencePrice = hiddenReferencePrice;
             }
 
+            // === Check for soft default ===
+
             // Check for soft default + save prices
             try this.tryPrice() returns (uint192 low, uint192 high, uint192) {
                 // {UoA/tok}, {UoA/tok}, {UoA/tok}

contracts/plugins/assets/curve/CurveStableRTokenMetapoolCollateral.sol

@@ -89,11 +89,16 @@ contract CurveStableRTokenMetapoolCollateral is CurveStableMetapoolCollateral {
                     assert(low == 0);
                 }
 
-                // Check RToken status
+                // Check pool status: inner RToken must be both isReady() and
+                // fullyCollateralized() to prevent injection of bad debt.
                 try pairedBasketHandler.isReady() returns (bool isReady) {
-                    if (!isReady) {
-                        markStatus(CollateralStatus.IFFY);
-                    } else if (low == 0 || _anyDepeggedInPool() || _anyDepeggedOutsidePool()) {
+                    if (
+                        !isReady ||
+                        low == 0 ||
+                        _anyDepeggedInPool() ||
+                        _anyDepeggedOutsidePool() ||
+                        !pairedBasketHandler.fullyCollateralized()
+                    ) {
                         // If the price is below the default-threshold price, default eventually
                         // uint192(+/-) is the same as Fix.plus/minus
                         markStatus(CollateralStatus.IFFY);

contracts/plugins/assets/curve/PoolTokens.sol

@@ -7,8 +7,18 @@ import "@openzeppelin/contracts/utils/math/Math.sol";
 import "contracts/plugins/assets/OracleLib.sol";
 import "contracts/libraries/Fixed.sol";
 
-// solhint-disable func-name-mixedcase
+// solhint-disable func-param-name-mixedcase, func-name-mixedcase
 interface ICurvePool {
+    // reentrancy check -- use with ETH / WETH pools
+    function claim_admin_fees() external;
+
+    function remove_liquidity(
+        uint256 _amount,
+        uint256[2] calldata min_amounts,
+        bool use_eth,
+        address receiver
+    ) external;
+
     // For Curve Plain Pools and V2 Metapools
     function coins(uint256) external view returns (address);
 

contracts/plugins/mocks/CurvePoolMock.sol

@@ -15,6 +15,15 @@ contract CurvePoolMock is ICurvePool {
         coins = _coins;
     }
 
+    function claim_admin_fees() external {}
+
+    function remove_liquidity(
+        uint256 _amount,
+        uint256[2] calldata min_amounts,
+        bool use_eth,
+        address receiver
+    ) external {}
+
     function setBalances(uint256[] memory newBalances) external {
         _balances = newBalances;
     }

contracts/plugins/mocks/CurveReentrantReceiver.sol

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: BlueOak-1.0.0
+pragma solidity 0.8.19;
+
+import "../../interfaces/IAsset.sol";
+
+contract CurveReentrantReceiver {
+    ICollateral curvePlugin;
+
+    constructor(ICollateral curvePlugin_) {
+        curvePlugin = curvePlugin_;
+        curvePlugin.refresh(); // should not revert yet
+    }
+
+    fallback() external payable {
+        // should revert if re-entrant
+        try curvePlugin.refresh() {} catch {
+            revert("refresh() reverted");
+        }
+    }
+}

scripts/addresses/1-tmp-assets-collateral.json

@@ -33,10 +33,10 @@
     "cUSDCv3": "0x33Ba1BC07b0fafb4BBC1520B330081b91ca6bdf0",
     "cvx3Pool": "0x8E5ADdC553962DAcdF48106B6218AC93DA9617b2",
     "cvxPayPool": "0x5315Fbe0CEB299F53aE375f65fd9376767C8224c",
-    "cvxeUSDFRAXBP": "0xE529B59C1764d6E5a274099Eb660DD9e130A5481",
+    "cvxeUSDFRAXBP": "0x994455cE66Fd984e2A0A0aca453e637810a8f032",
     "cvxMIM3Pool": "0x3d21f841C0Fb125176C1DBDF0DE196b071323A75",
-    "cvxETHPlusETH": "0xc4a5Fb266E8081D605D87f0b1290F54B0a5Dc221",
-    "crveUSDFRAXBP": "0x945b0ad788dD6dB3864AB23876C68C1bf000d237",
+    "cvxETHPlusETH": "0x05F164E71C46a8f8FB2ba71550a00eeC9FCd85cd",
+    "crveUSDFRAXBP": "0xCDC5f5E041b49Cad373E94930E2b3bE30be70535",
     "crvMIM3Pool": "0x692cf8CE08d03eF1f8C3dCa82F67935fa9417B62",
     "crv3Pool": "0xf59a7987EDd5380cbAb30c37D1c808686f9b67B9",
     "sDAI": "0x62a9DDC6FF6077E823690118eCc935d16A8de47e",
@@ -119,4 +119,4 @@
     "CRV": "0xD533a949740bb3306d119CC777fa900bA034cd52",
     "CVX": "0x4e3FBD56CD56c3e72c1403e103b45Db9da5B9D2B"
   }
-}
+}

scripts/addresses/mainnet-3.4.0/1-tmp-assets-collateral.json

@@ -33,10 +33,10 @@
     "cUSDCv3": "0x33Ba1BC07b0fafb4BBC1520B330081b91ca6bdf0",
     "cvx3Pool": "0x8E5ADdC553962DAcdF48106B6218AC93DA9617b2",
     "cvxPayPool": "0x5315Fbe0CEB299F53aE375f65fd9376767C8224c",
-    "cvxeUSDFRAXBP": "0xE529B59C1764d6E5a274099Eb660DD9e130A5481",
+    "cvxeUSDFRAXBP": "0x994455cE66Fd984e2A0A0aca453e637810a8f032",
     "cvxMIM3Pool": "0x3d21f841C0Fb125176C1DBDF0DE196b071323A75",
-    "cvxETHPlusETH": "0xc4a5Fb266E8081D605D87f0b1290F54B0a5Dc221",
-    "crveUSDFRAXBP": "0x945b0ad788dD6dB3864AB23876C68C1bf000d237",
+    "cvxETHPlusETH": "0x05F164E71C46a8f8FB2ba71550a00eeC9FCd85cd",
+    "crveUSDFRAXBP": "0xCDC5f5E041b49Cad373E94930E2b3bE30be70535",
     "crvMIM3Pool": "0x692cf8CE08d03eF1f8C3dCa82F67935fa9417B62",
     "crv3Pool": "0xf59a7987EDd5380cbAb30c37D1c808686f9b67B9",
     "sDAI": "0x62a9DDC6FF6077E823690118eCc935d16A8de47e",