fix: Fix collateral behavior of zero-ltv assets (#820)

* fix: patch zero ltv transfer

* fix: revert undesired changes

* fix: change implementation

* fix: add docs

* fix: rename error

* fix: improved isolation mode enter mechanic

* fix: improve tests

* fix: remove check from bridge as anotehr role is used already

* fix: use acl manager

* fix: flashloan receiver.executeOperation params

* fix: fix comment

* fix: move role to constant

* fix: commit broken test

* fix: add additional test

* fix: add flashloan test

* fix: add additional test

* fix: fix tests

* fix: prune fl fix

* Update package.json

* fix: resolve conflicts

* fix: add comments

* fix: also add automatic isolation logic to mintUnbacked

fix: update docs

* fix: update test

* fix: add some more ltv0 tests

* feat: fix tests & add another one

* fix: Fetch addressesProvider from AToken

---------

Co-authored-by: miguelmtz <36620902+miguelmtzinf@users.noreply.github.com>
Co-authored-by: miguelmtzinf <miguelmtz.mail@gmail.com>

contracts/protocol/libraries/helpers/Errors.sol

@@ -67,7 +67,7 @@ library Errors {
   string public constant PRICE_ORACLE_SENTINEL_CHECK_FAILED = '59'; // 'Price oracle sentinel validation failed'
   string public constant ASSET_NOT_BORROWABLE_IN_ISOLATION = '60'; // 'Asset is not borrowable in isolation mode'
   string public constant RESERVE_ALREADY_INITIALIZED = '61'; // 'Reserve has already been initialized'
-  string public constant USER_IN_ISOLATION_MODE = '62'; // 'User is in isolation mode'
+  string public constant USER_IN_ISOLATION_MODE_OR_LTV_ZERO = '62'; // 'User is in isolation mode or ltv is zero'
   string public constant INVALID_LTV = '63'; // 'Invalid ltv parameter for the reserve'
   string public constant INVALID_LIQ_THRESHOLD = '64'; // 'Invalid liquidity threshold parameter for the reserve'
   string public constant INVALID_LIQ_BONUS = '65'; // 'Invalid liquidity bonus parameter for the reserve'

contracts/protocol/libraries/logic/BridgeLogic.sol

@@ -86,11 +86,12 @@ library BridgeLogic {
 
     if (isFirstSupply) {
       if (
-        ValidationLogic.validateUseAsCollateral(
+        ValidationLogic.validateAutomaticUseAsCollateral(
           reservesData,
           reservesList,
           userConfig,
-          reserveCache.reserveConfiguration
+          reserveCache.reserveConfiguration,
+          reserveCache.aTokenAddress
         )
       ) {
         userConfig.setUsingAsCollateral(reserve.id, true);

contracts/protocol/libraries/logic/LiquidationLogic.sol

@@ -300,11 +300,12 @@ library LiquidationLogic {
     if (liquidatorPreviousATokenBalance == 0) {
       DataTypes.UserConfigurationMap storage liquidatorConfig = usersConfig[msg.sender];
       if (
-        ValidationLogic.validateUseAsCollateral(
+        ValidationLogic.validateAutomaticUseAsCollateral(
           reservesData,
           reservesList,
           liquidatorConfig,
-          collateralReserve.configuration
+          collateralReserve.configuration,
+          collateralReserve.aTokenAddress
         )
       ) {
         liquidatorConfig.setUsingAsCollateral(collateralReserve.id, true);

contracts/protocol/libraries/logic/SupplyLogic.sol

@@ -75,11 +75,12 @@ library SupplyLogic {
 
     if (isFirstSupply) {
       if (
-        ValidationLogic.validateUseAsCollateral(
+        ValidationLogic.validateAutomaticUseAsCollateral(
           reservesData,
           reservesList,
           userConfig,
-          reserveCache.reserveConfiguration
+          reserveCache.reserveConfiguration,
+          reserveCache.aTokenAddress
         )
       ) {
         userConfig.setUsingAsCollateral(reserve.id, true);
@@ -212,11 +213,12 @@ library SupplyLogic {
       if (params.balanceToBefore == 0) {
         DataTypes.UserConfigurationMap storage toConfig = usersConfig[params.to];
         if (
-          ValidationLogic.validateUseAsCollateral(
+          ValidationLogic.validateAutomaticUseAsCollateral(
             reservesData,
             reservesList,
             toConfig,
-            reserve.configuration
+            reserve.configuration,
+            reserve.aTokenAddress
           )
         ) {
           toConfig.setUsingAsCollateral(reserveId, true);
@@ -270,7 +272,7 @@ library SupplyLogic {
           userConfig,
           reserveCache.reserveConfiguration
         ),
-        Errors.USER_IN_ISOLATION_MODE
+        Errors.USER_IN_ISOLATION_MODE_OR_LTV_ZERO
       );
 
       userConfig.setUsingAsCollateral(reserve.id, true);

contracts/protocol/libraries/logic/ValidationLogic.sol

@@ -10,6 +10,8 @@ import {IScaledBalanceToken} from '../../../interfaces/IScaledBalanceToken.sol';
 import {IPriceOracleGetter} from '../../../interfaces/IPriceOracleGetter.sol';
 import {IAToken} from '../../../interfaces/IAToken.sol';
 import {IPriceOracleSentinel} from '../../../interfaces/IPriceOracleSentinel.sol';
+import {IPoolAddressesProvider} from '../../../interfaces/IPoolAddressesProvider.sol';
+import {IAccessControl} from '../../../dependencies/openzeppelin/contracts/IAccessControl.sol';
 import {ReserveConfiguration} from '../configuration/ReserveConfiguration.sol';
 import {UserConfiguration} from '../configuration/UserConfiguration.sol';
 import {Errors} from '../helpers/Errors.sol';
@@ -19,6 +21,7 @@ import {DataTypes} from '../types/DataTypes.sol';
 import {ReserveLogic} from './ReserveLogic.sol';
 import {GenericLogic} from './GenericLogic.sol';
 import {SafeCast} from '../../../dependencies/openzeppelin/contracts/SafeCast.sol';
+import {IncentivizedERC20} from '../../tokenization/base/IncentivizedERC20.sol';
 
 /**
  * @title ReserveLogic library
@@ -49,6 +52,12 @@ library ValidationLogic {
    */
   uint256 public constant HEALTH_FACTOR_LIQUIDATION_THRESHOLD = 1e18;
 
+  /**
+   * @dev Role identifier for the role allowed to supply isolated reserves as collateral
+   */
+  bytes32 public constant ISOLATED_COLLATERAL_SUPPLIER_ROLE =
+    keccak256('ISOLATED_COLLATERAL_SUPPLIER');
+
   /**
    * @notice Validates a supply action.
    * @param reserveCache The cached data of the reserve
@@ -664,7 +673,7 @@ library ValidationLogic {
       Errors.INCONSISTENT_EMODE_CATEGORY
     );
 
-    //eMode can always be enabled if the user hasn't supplied anything
+    // eMode can always be enabled if the user hasn't supplied anything
     if (userConfig.isEmpty()) {
       return;
     }
@@ -688,10 +697,8 @@ library ValidationLogic {
   }
 
   /**
-   * @notice Validates if an asset can be activated as collateral in the following actions: supply, transfer,
-   * set as collateral, mint unbacked, and liquidate
-   * @dev This is used to ensure that the constraints for isolated assets are respected by all the actions that
-   * generate transfers of aTokens
+   * @notice Validates the action of activating the asset as collateral.
+   * @dev Only possible if the asset has non-zero LTV and the user is not in isolation mode
    * @param reservesData The state of all the reserves
    * @param reservesList The addresses of all the active reserves
    * @param userConfig the user configuration
@@ -704,11 +711,46 @@ library ValidationLogic {
     DataTypes.UserConfigurationMap storage userConfig,
     DataTypes.ReserveConfigurationMap memory reserveConfig
   ) internal view returns (bool) {
+    if (reserveConfig.getLtv() == 0) {
+      return false;
+    }
     if (!userConfig.isUsingAsCollateralAny()) {
       return true;
     }
     (bool isolationModeActive, , ) = userConfig.getIsolationModeState(reservesData, reservesList);
 
     return (!isolationModeActive && reserveConfig.getDebtCeiling() == 0);
   }
+
+  /**
+   * @notice Validates if an asset should be automatically activated as collateral in the following actions: supply, 
+   * transfer, mint unbacked, and liquidate
+   * @dev This is used to ensure that isolated assets are not enabled as collateral automatically
+   * @param reservesData The state of all the reserves
+   * @param reservesList The addresses of all the active reserves
+   * @param userConfig the user configuration
+   * @param reserveConfig The reserve configuration
+   * @return True if the asset can be activated as collateral, false otherwise
+   */
+  function validateAutomaticUseAsCollateral(
+    mapping(address => DataTypes.ReserveData) storage reservesData,
+    mapping(uint256 => address) storage reservesList,
+    DataTypes.UserConfigurationMap storage userConfig,
+    DataTypes.ReserveConfigurationMap memory reserveConfig,
+    address aTokenAddress
+  ) internal view returns (bool) {
+    if (reserveConfig.getDebtCeiling() != 0) {
+      // ensures only the ISOLATED_COLLATERAL_SUPPLIER_ROLE can enable collateral as side-effect of an action
+      IPoolAddressesProvider addressesProvider = IncentivizedERC20(aTokenAddress)
+        .POOL()
+        .ADDRESSES_PROVIDER();
+      if (
+        !IAccessControl(addressesProvider.getACLManager()).hasRole(
+          ISOLATED_COLLATERAL_SUPPLIER_ROLE,
+          msg.sender
+        )
+      ) return false;
+    }
+    return validateUseAsCollateral(reservesData, reservesList, userConfig, reserveConfig);
+  }
 }

contracts/protocol/libraries/types/DataTypes.sol

@@ -78,11 +78,7 @@ library DataTypes {
     string label;
   }
 
-  enum InterestRateMode {
-    NONE,
-    STABLE,
-    VARIABLE
-  }
+  enum InterestRateMode {NONE, STABLE, VARIABLE}
 
   struct ReserveCache {
     uint256 currScaledVariableDebt;

helpers/types.ts

@@ -131,7 +131,7 @@ export enum ProtocolErrors {
   PRICE_ORACLE_SENTINEL_CHECK_FAILED = '59', // 'Price oracle sentinel validation failed'
   ASSET_NOT_BORROWABLE_IN_ISOLATION = '60', // 'Asset is not borrowable in isolation mode'
   RESERVE_ALREADY_INITIALIZED = '61', // 'Reserve has already been initialized'
-  USER_IN_ISOLATION_MODE = '62', // 'User is in isolation mode'
+  USER_IN_ISOLATION_MODE_OR_LTV_ZERO = '62', // 'User is in isolation mode or ltv is zero'
   INVALID_LTV = '63', // 'Invalid ltv parameter for the reserve'
   INVALID_LIQ_THRESHOLD = '64', // 'Invalid liquidity threshold parameter for the reserve'
   INVALID_LIQ_BONUS = '65', // 'Invalid liquidity bonus parameter for the reserve'