Add IRM whitelist

src/Blue.sol

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity 0.8.20;
 
+import {IIRM} from "src/interfaces/IIRM.sol";
 import {IERC20} from "src/interfaces/IERC20.sol";
 import {IOracle} from "src/interfaces/IOracle.sol";
 
@@ -22,15 +23,10 @@ struct Market {
     IERC20 collateralAsset;
     IOracle borrowableOracle;
     IOracle collateralOracle;
+    IIRM irm;
     uint lLTV;
 }
 
-function irm(uint utilization) pure returns (uint) {
-    // Divide by the number of seconds in a year.
-    // This is a very simple model (to refine later) where x% utilization corresponds to x% APR.
-    return utilization / 365 days;
-}
-
 contract Blue is Ownable {
     using MathLib for uint;
     using SafeTransferLib for IERC20;
@@ -53,16 +49,23 @@ contract Blue is Ownable {
     mapping(Id => uint) public totalBorrowShares;
     // Interests last update (used to check if a market has been created).
     mapping(Id => uint) public lastUpdate;
+    // IRM whitelist.
+    mapping(address => uint) public isIRMWhitelisted;
 
     constructor(address owner) Ownable(owner) {}
 
     // Markets management.
 
     function createMarket(Market calldata market) external {
         Id id = Id.wrap(keccak256(abi.encode(market)));
+        require(isIRMWhitelisted[address(market.irm)] == 1, "IRM not whitelisted");
         require(lastUpdate[id] == 0, "market already exists");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
+    }
+
+    function whitelistIRM(address irm) external onlyOwner {
+        isIRMWhitelisted[irm] = 1;
     }
 
     // Supply management.
@@ -72,7 +75,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(amount > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         if (totalSupply[id] == 0) {
             supplyShare[id][msg.sender] = WAD;
@@ -93,7 +96,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(amount > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         uint shares = amount.wMul(totalSupplyShares[id]).wDiv(totalSupply[id]);
         supplyShare[id][msg.sender] -= shares;
@@ -113,7 +116,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(amount > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         if (totalBorrow[id] == 0) {
             borrowShare[id][msg.sender] = WAD;
@@ -137,7 +140,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(amount > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         uint shares = amount.wMul(totalBorrowShares[id]).wDiv(totalBorrow[id]);
         borrowShare[id][msg.sender] -= shares;
@@ -155,7 +158,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(amount > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         collateral[id][msg.sender] += amount;
 
@@ -167,7 +170,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(amount > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         collateral[id][msg.sender] -= amount;
 
@@ -183,7 +186,7 @@ contract Blue is Ownable {
         require(lastUpdate[id] != 0, "unknown market");
         require(seized > 0, "zero amount");
 
-        accrueInterests(id);
+        accrueInterests(id, market.irm);
 
         require(!isHealthy(market, id, borrower), "cannot liquidate a healthy position");
 
@@ -211,14 +214,12 @@ contract Blue is Ownable {
 
     // Interests management.
 
-    function accrueInterests(Id id) private {
+    function accrueInterests(Id id, IIRM irm) private {
         uint marketTotalSupply = totalSupply[id];
 
         if (marketTotalSupply != 0) {
             uint marketTotalBorrow = totalBorrow[id];
-            uint utilization = marketTotalBorrow.wDiv(marketTotalSupply);
-            uint borrowRate = irm(utilization);
-            uint accruedInterests = marketTotalBorrow.wMul(borrowRate).wMul(block.timestamp - lastUpdate[id]);
+            uint accruedInterests = marketTotalBorrow.wMul(irm.rate()).wMul(block.timestamp - lastUpdate[id]);
             totalSupply[id] = marketTotalSupply + accruedInterests;
             totalBorrow[id] = marketTotalBorrow + accruedInterests;
         }

src/interfaces/IIRM.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity >=0.5.0;
+
+interface IIRM {
+	function rate() external returns (uint);
+}

src/mocks/IRMMock.sol

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.8.20;
+
+import {IERC20} from "src/interfaces/IERC20.sol";
+import {IOracle} from "src/interfaces/IOracle.sol";
+
+import {MathLib} from "src/libraries/MathLib.sol";
+
+import "src/Blue.sol";
+
+contract IRMMock is IIRM {
+	using MathLib for uint;
+
+	Blue public blue;
+	Id public marketId;
+
+	constructor (Blue blueInstance) {
+		blue = Blue(blueInstance);
+	}
+
+	function setId(Id id) external {
+		marketId = id;
+	}
+
+	function rate() external view returns (uint) {
+		uint utilization = blue.totalBorrow(marketId).wDiv(blue.totalSupply(marketId));
+
+		// Divide by the number of seconds in a year.
+		// This is a very simple model (to refine later) where x% utilization corresponds to x% APR.
+		return utilization / 365 days;
+	}
+}

test/forge/Blue.t.sol

@@ -10,6 +10,7 @@ import "forge-std/console.sol";
 import "src/Blue.sol";
 import {ERC20Mock as ERC20} from "src/mocks/ERC20Mock.sol";
 import {OracleMock as Oracle} from "src/mocks/OracleMock.sol";
+import {IRMMock as IRM} from "src/mocks/IRMMock.sol";
 
 contract BlueTest is Test {
     using MathLib for uint;
@@ -23,23 +24,27 @@ contract BlueTest is Test {
     ERC20 private collateralAsset;
     Oracle private borrowableOracle;
     Oracle private collateralOracle;
+    IRM private irm;
     Market public market;
     Id public id;
 
     function setUp() public {
         // Create Blue.
-        blue = new Blue(msg.sender);
+        blue = new Blue(address(this));
 
         // List a market.
         borrowableAsset = new ERC20("borrowable", "B", 18);
         collateralAsset = new ERC20("collateral", "C", 18);
         borrowableOracle = new Oracle();
         collateralOracle = new Oracle();
+        irm = new IRM(blue);
         market = Market(
-            IERC20(address(borrowableAsset)), IERC20(address(collateralAsset)), borrowableOracle, collateralOracle, lLTV
+            IERC20(address(borrowableAsset)), IERC20(address(collateralAsset)), borrowableOracle, collateralOracle, irm, lLTV
         );
+        blue.whitelistIRM(address(irm));
         id = Id.wrap(keccak256(abi.encode(market)));
 
+        irm.setId(id);
         blue.createMarket(market);
 
         // We set the price of the borrowable asset to zero so that borrowers
@@ -115,6 +120,20 @@ contract BlueTest is Test {
         blue2.transferOwnership(newOwner);
     }
 
+    function testWhitelistIRMWhenNotOwner(address attacker) public {
+        vm.assume(attacker != blue.owner());
+
+        vm.prank(attacker);
+        vm.expectRevert("not owner");
+        blue.whitelistIRM(address(0xdead));
+    }
+
+    function testWhitelistIRM(address newIRM) public {
+        blue.whitelistIRM(newIRM);
+
+        assertEq(blue.isIRMWhitelisted(newIRM), 1);
+    }
+
     function testSupply(uint amount) public {
         amount = bound(amount, 1, 2 ** 64);