From a2fcb51508529036378b72187a895eb4b21a7a5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=9Fingen?= <bingen@liquity.org>
Date: Fri, 20 Sep 2024 10:56:37 +0100
Subject: [PATCH] fix: Allow owner to set any interest rate even if trove has
 delegate

---
 contracts/src/BorrowerOperations.sol          | 22 ++++++++++---------
 .../test/interestIndividualDelegation.t.sol   | 16 ++++++++++++++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/contracts/src/BorrowerOperations.sol b/contracts/src/BorrowerOperations.sol
index 322b6f2a..d1478df0 100644
--- a/contracts/src/BorrowerOperations.sol
+++ b/contracts/src/BorrowerOperations.sol
@@ -520,7 +520,7 @@ contract BorrowerOperations is LiquityBase, AddRemoveManagers, IBorrowerOperatio
         _requireIsNotInBatch(_troveId);
         address owner = troveNFT.ownerOf(_troveId);
         _requireSenderIsOwnerOrInterestManager(_troveId, owner);
-        _requireInterestRateInDelegateRange(_troveId, _newAnnualInterestRate);
+        _requireInterestRateInDelegateRange(_troveId, _newAnnualInterestRate, owner);
         _requireTroveIsActive(troveManagerCached, _troveId);
 
         LatestTroveData memory trove = troveManagerCached.getLatestTroveData(_troveId);
@@ -1287,6 +1287,17 @@ contract BorrowerOperations is LiquityBase, AddRemoveManagers, IBorrowerOperatio
         }
     }
 
+    function _requireInterestRateInDelegateRange(uint256 _troveId, uint256 _annualInterestRate, address _owner) internal view {
+        InterestIndividualDelegate memory individualDelegate = interestIndividualDelegateOf[_troveId];
+        // We have previously checked that sender is either owner or delegate
+        // If it’s owner, this restriction doesn’t apply
+        if (individualDelegate.account == msg.sender) {
+            _requireInterestRateInRange(
+                _annualInterestRate, individualDelegate.minInterestRate, individualDelegate.maxInterestRate
+            );
+        }
+    }
+
     function _requireIsNotInBatch(uint256 _troveId) internal view {
         if (interestBatchManagerOf[_troveId] != address(0)) {
             revert TroveInBatch();
@@ -1442,15 +1453,6 @@ contract BorrowerOperations is LiquityBase, AddRemoveManagers, IBorrowerOperatio
         if (_minInterestRate >= _maxInterestRate) revert MinGeMax();
     }
 
-    function _requireInterestRateInDelegateRange(uint256 _troveId, uint256 _annualInterestRate) internal view {
-        InterestIndividualDelegate memory individualDelegate = interestIndividualDelegateOf[_troveId];
-        if (individualDelegate.account != address(0)) {
-            _requireInterestRateInRange(
-                _annualInterestRate, individualDelegate.minInterestRate, individualDelegate.maxInterestRate
-            );
-        }
-    }
-
     function _requireInterestRateInBatchManagerRange(address _interestBatchManagerAddress, uint256 _annualInterestRate)
         internal
         view
diff --git a/contracts/src/test/interestIndividualDelegation.t.sol b/contracts/src/test/interestIndividualDelegation.t.sol
index dad517b0..f8a8c5b1 100644
--- a/contracts/src/test/interestIndividualDelegation.t.sol
+++ b/contracts/src/test/interestIndividualDelegation.t.sol
@@ -102,6 +102,22 @@ contract InterestIndividualDelegationTest is DevTestSetup {
         vm.stopPrank();
     }
 
+    function testOwnerCanSetInterestBelowMin() public {
+        uint256 troveId = openTroveAndSetIndividualDelegate();
+
+        vm.startPrank(A);
+        borrowerOperations.adjustTroveInterestRate(troveId, MIN_ANNUAL_INTEREST_RATE, 0, 0, 1e24);
+        vm.stopPrank();
+    }
+
+    function testOwnerCanSetInterestAboveMax() public {
+        uint256 troveId = openTroveAndSetIndividualDelegate();
+
+        vm.startPrank(A);
+        borrowerOperations.adjustTroveInterestRate(troveId, 50e16, 0, 0, 1e24);
+        vm.stopPrank();
+    }
+
     function testSetDelegateRevertsIfTroveIsClosed() public {
         vm.startPrank(B);
         borrowerOperations.registerBatchManager(1e16, 20e16, 5e16, 25e14, MIN_INTEREST_RATE_CHANGE_PERIOD);