fix: bound rate

morpho-org · Feb 28, 2024 · a0fa8f4 · a0fa8f4
1 parent 23259f8
commit a0fa8f4
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Showing 2 changed files with 20 additions and 0 deletions.
diff --git a/src/fixed-rate-irm/FixedRateIrm.sol b/src/fixed-rate-irm/FixedRateIrm.sol
@@ -15,6 +15,8 @@ string constant RATE_NOT_SET = "rate not set";
 string constant RATE_SET = "rate set";
 /// @dev Thrown when trying to set the rate at zero.
 string constant RATE_ZERO = "rate zero";
+/// @dev Thrown when trying to set a rate that is too high.
+string constant RATE_TOO_HIGH = "rate too high";
 
 /// @title FixedRateIrm
 /// @author Morpho Labs
@@ -27,6 +29,11 @@ contract FixedRateIrm is IFixedRateIrm {
     /// @notice Emitted when a borrow rate is set.
     event SetBorrowRate(Id indexed id, uint256 newBorrowRate);
 
+    /* CONSTANTS */
+
+    /// @notice Max settable borrow rate (800%).
+    uint256 public constant MAX_BORROW_RATE = 8.0 ether / uint256(365 days);
+
     /* STORAGE */
 
     /// @notice Borrow rates.
@@ -40,6 +47,7 @@ contract FixedRateIrm is IFixedRateIrm {
     function setBorrowRate(Id id, uint256 newBorrowRate) external {
         require(borrowRateStored[id] == 0, RATE_SET);
         require(newBorrowRate != 0, RATE_ZERO);
+        require(newBorrowRate <= MAX_BORROW_RATE, RATE_TOO_HIGH);
 
         borrowRateStored[id] = newBorrowRate;
 

diff --git a/test/forge/FixedRateIrmTest.sol b/test/forge/FixedRateIrmTest.sol
@@ -18,13 +18,15 @@ contract FixedRateIrmTest is Test {
 
     function testSetBorrowRate(Id id, uint256 newBorrowRate) external {
         vm.assume(newBorrowRate != 0);
+        vm.assume(newBorrowRate <= fixedRateIrm.MAX_BORROW_RATE());
 
         fixedRateIrm.setBorrowRate(id, newBorrowRate);
         assertEq(fixedRateIrm.borrowRateStored(id), newBorrowRate);
     }
 
     function testSetBorrowRateEvent(Id id, uint256 newBorrowRate) external {
         vm.assume(newBorrowRate != 0);
+        vm.assume(newBorrowRate <= fixedRateIrm.MAX_BORROW_RATE());
 
         vm.expectEmit(true, true, true, true, address(fixedRateIrm));
         emit SetBorrowRate(id, newBorrowRate);
@@ -33,7 +35,9 @@ contract FixedRateIrmTest is Test {
 
     function testSetBorrowRateAlreadySet(Id id, uint256 newBorrowRate1, uint256 newBorrowRate2) external {
         vm.assume(newBorrowRate1 != 0);
+        vm.assume(newBorrowRate1 <= fixedRateIrm.MAX_BORROW_RATE());
         vm.assume(newBorrowRate2 != 0);
+        vm.assume(newBorrowRate2 <= fixedRateIrm.MAX_BORROW_RATE());
         fixedRateIrm.setBorrowRate(id, newBorrowRate1);
         vm.expectRevert(bytes(RATE_SET));
         fixedRateIrm.setBorrowRate(id, newBorrowRate2);
@@ -44,8 +48,15 @@ contract FixedRateIrmTest is Test {
         fixedRateIrm.setBorrowRate(id, 0);
     }
 
+    function testSetBorrowRateRateTooHigh(Id id, uint256 newBorrowRate) external {
+        vm.assume(newBorrowRate > fixedRateIrm.MAX_BORROW_RATE());
+        vm.expectRevert(bytes(RATE_TOO_HIGH));
+        fixedRateIrm.setBorrowRate(id, newBorrowRate);
+    }
+
     function testBorrowRate(MarketParams memory marketParams, Market memory market, uint256 newBorrowRate) external {
         vm.assume(newBorrowRate != 0);
+        vm.assume(newBorrowRate <= fixedRateIrm.MAX_BORROW_RATE());
         fixedRateIrm.setBorrowRate(marketParams.id(), newBorrowRate);
         assertEq(fixedRateIrm.borrowRate(marketParams, market), newBorrowRate);
     }
@@ -59,6 +70,7 @@ contract FixedRateIrmTest is Test {
         external
     {
         vm.assume(newBorrowRate != 0);
+        vm.assume(newBorrowRate <= fixedRateIrm.MAX_BORROW_RATE());
         fixedRateIrm.setBorrowRate(marketParams.id(), newBorrowRate);
         assertEq(fixedRateIrm.borrowRateView(marketParams, market), newBorrowRate);
     }