diff --git a/contracts/interfaces/ILendingPool.sol b/contracts/interfaces/ILendingPool.sol index f44a458a..b893c16b 100644 --- a/contracts/interfaces/ILendingPool.sol +++ b/contracts/interfaces/ILendingPool.sol @@ -349,11 +349,14 @@ interface ILendingPool { function getReserveData(address asset) external view returns (ReserveLogic.ReserveData memory); - function balanceDecreaseAllowed( - address reserve, - address user, - uint256 amount - ) external view returns (bool); + function finalizeTransfer( + address asset, + address from, + address to, + uint256 amount, + uint256 balanceFromAfter, + uint256 balanceToBefore + ) external; function getReservesList() external view returns (address[] memory); diff --git a/contracts/lendingpool/LendingPool.sol b/contracts/lendingpool/LendingPool.sol index 3f490365..fde9d760 100644 --- a/contracts/lendingpool/LendingPool.sol +++ b/contracts/lendingpool/LendingPool.sol @@ -724,29 +724,46 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage } /** - * @dev validate if a balance decrease for an asset is allowed + * @dev validates and finalizes an aToken transfer * @param asset the address of the reserve - * @param user the user related to the balance decrease + * @param from the user from which the aTokens are transferred + * @param to the user receiving the aTokens * @param amount the amount being transferred/redeemed - * @return true if the balance decrease can be allowed, false otherwise + * @param balanceFromBefore the balance of the from user before the transfer + * @param balanceToBefore the balance of the to user before the transfer */ - function balanceDecreaseAllowed( + function finalizeTransfer( address asset, - address user, - uint256 amount - ) external override view returns (bool) { + address from, + address to, + uint256 amount, + uint256 balanceFromBefore, + uint256 balanceToBefore + ) external override { _whenNotPaused(); - return - GenericLogic.balanceDecreaseAllowed( - asset, - user, - amount, - _reserves, - _usersConfig[user], - _reservesList, - _reservesCount, - _addressesProvider.getPriceOracle() - ); + + ValidationLogic.validateTransfer( + from, + _reserves, + _usersConfig[from], + _reservesList, + _reservesCount, + _addressesProvider.getPriceOracle() + ); + + uint256 reserveId = _reserves[asset].id; + + if (from != to) { + if (balanceFromBefore.sub(amount) == 0) { + UserConfiguration.Map storage fromConfig = _usersConfig[from]; + fromConfig.setUsingAsCollateral(reserveId, false); + } + + if (balanceToBefore == 0) { + UserConfiguration.Map storage toConfig = _usersConfig[to]; + toConfig.setUsingAsCollateral(reserveId, true); + } + } } /** @@ -913,7 +930,6 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage * @dev adds a reserve to the array of the _reserves address **/ function _addReserveToList(address asset) internal { - uint256 reservesCount = _reservesCount; require(reservesCount < MAX_NUMBER_RESERVES, Errors.NO_MORE_RESERVES_ALLOWED); diff --git a/contracts/libraries/logic/ValidationLogic.sol b/contracts/libraries/logic/ValidationLogic.sol index 947d84ea..c772e307 100644 --- a/contracts/libraries/logic/ValidationLogic.sol +++ b/contracts/libraries/logic/ValidationLogic.sol @@ -13,6 +13,8 @@ import {ReserveConfiguration} from '../configuration/ReserveConfiguration.sol'; import {UserConfiguration} from '../configuration/UserConfiguration.sol'; import {Errors} from '../helpers/Errors.sol'; import {Helpers} from '../helpers/Helpers.sol'; +import "@nomiclabs/buidler/console.sol"; + /** * @title ReserveLogic library @@ -46,6 +48,11 @@ library ValidationLogic { * @param reserveAddress the address of the reserve * @param amount the amount to be withdrawn * @param userBalance the balance of the user + * @param reservesData the reserves state + * @param userConfig the user configuration + * @param reserves the addresses of the reserves + * @param reservesCount the number of reserves + * @param oracle the price oracle */ function validateWithdraw( address reserveAddress, @@ -389,4 +396,37 @@ library ValidationLogic { return (uint256(Errors.CollateralManagerErrors.NO_ERROR), Errors.NO_ERRORS); } + + /** + * @dev validates an aToken transfer. + * @param from the user from which the aTokens are being transferred + * @param reservesData the state of all the reserves + * @param userConfig the state of the user for the specific reserve + * @param reserves the addresses of all the active reserves + * @param oracle the price oracle + */ + function validateTransfer( + address from, + mapping(address => ReserveLogic.ReserveData) storage reservesData, + UserConfiguration.Map storage userConfig, + mapping(uint256 => address) storage reserves, + uint256 reservesCount, + address oracle + ) internal view { + (, , , , uint256 healthFactor) = GenericLogic.calculateUserAccountData( + from, + reservesData, + userConfig, + reserves, + reservesCount, + oracle + ); + + console.log("Health factor after transfer %s", healthFactor); + + require( + healthFactor >= GenericLogic.HEALTH_FACTOR_LIQUIDATION_THRESHOLD, + Errors.TRANSFER_NOT_ALLOWED + ); + } } diff --git a/contracts/tokenization/AToken.sol b/contracts/tokenization/AToken.sol index 5641ebf8..adc1771b 100644 --- a/contracts/tokenization/AToken.sol +++ b/contracts/tokenization/AToken.sol @@ -241,16 +241,6 @@ contract AToken is VersionedInitializable, IncentivizedERC20, IAToken { return super.totalSupply(); } - /** - * @dev Used to validate transfers before actually executing them. - * @param user address of the user to check - * @param amount the amount to check - * @return true if the user can transfer amount, false otherwise - **/ - function isTransferAllowed(address user, uint256 amount) public override view returns (bool) { - return POOL.balanceDecreaseAllowed(UNDERLYING_ASSET_ADDRESS, user, amount); - } - /** * @dev transfers the underlying asset to the target. Used by the lendingpool to transfer * assets in borrow(), redeem() and flashLoan() @@ -317,14 +307,24 @@ contract AToken is VersionedInitializable, IncentivizedERC20, IAToken { uint256 amount, bool validate ) internal { - if (validate) { - require(isTransferAllowed(from, amount), Errors.TRANSFER_NOT_ALLOWED); - } - uint256 index = POOL.getReserveNormalizedIncome(UNDERLYING_ASSET_ADDRESS); + uint256 fromBalanceBefore = super.balanceOf(from).rayMul(index); + uint256 toBalanceBefore = super.balanceOf(to).rayMul(index); + super._transfer(from, to, amount.rayDiv(index)); + if (validate) { + POOL.finalizeTransfer( + UNDERLYING_ASSET_ADDRESS, + from, + to, + amount, + fromBalanceBefore, + toBalanceBefore + ); + } + emit BalanceTransfer(from, to, amount, index); } diff --git a/contracts/tokenization/interfaces/IAToken.sol b/contracts/tokenization/interfaces/IAToken.sol index 00f63b20..055e3f5d 100644 --- a/contracts/tokenization/interfaces/IAToken.sol +++ b/contracts/tokenization/interfaces/IAToken.sol @@ -54,8 +54,6 @@ interface IAToken is IERC20, IScaledBalanceToken { uint256 value ) external; - function isTransferAllowed(address user, uint256 amount) external view returns (bool); - /** * @dev transfer the amount of the underlying asset to the user * @param user address of the user diff --git a/deployed-contracts.json b/deployed-contracts.json index d7001b2a..4b961b6c 100644 --- a/deployed-contracts.json +++ b/deployed-contracts.json @@ -628,4 +628,4 @@ "deployer": "0xc783df8a850f42e7F7e57013759C285caa701eB6" } } -} +} \ No newline at end of file diff --git a/test/atoken-transfer.spec.ts b/test/atoken-transfer.spec.ts index 0e207e17..89ed584f 100644 --- a/test/atoken-transfer.spec.ts +++ b/test/atoken-transfer.spec.ts @@ -46,8 +46,8 @@ makeSuite('AToken: Transfer', (testEnv: TestEnv) => { ); }); - it('User 0 deposits 1 WETH and user 1 tries to borrow, but the aTokens received as a transfer are not available as collateral (revert expected)', async () => { - const {users, pool, weth} = testEnv; + it('User 0 deposits 1 WETH and user 1 tries to borrow the WETH with the received DAI as collateral', async () => { + const {users, pool, weth, helpersContract} = testEnv; const userAddress = await pool.signer.getAddress(); await weth.connect(users[0].signer).mint(await convertToCurrencyDecimals(weth.address, '1')); @@ -57,26 +57,6 @@ makeSuite('AToken: Transfer', (testEnv: TestEnv) => { await pool .connect(users[0].signer) .deposit(weth.address, ethers.utils.parseEther('1.0'), userAddress, '0'); - await expect( - pool - .connect(users[1].signer) - .borrow( - weth.address, - ethers.utils.parseEther('0.1'), - RateMode.Stable, - AAVE_REFERRAL, - users[1].address - ), - COLLATERAL_BALANCE_IS_0 - ).to.be.revertedWith(COLLATERAL_BALANCE_IS_0); - }); - - it('User 1 sets the DAI as collateral and borrows, tries to transfer everything back to user 0 (revert expected)', async () => { - const {users, pool, aDai, dai, weth} = testEnv; - await pool.connect(users[1].signer).setUserUseReserveAsCollateral(dai.address, true); - - const aDAItoTransfer = await convertToCurrencyDecimals(dai.address, '1000'); - await pool .connect(users[1].signer) .borrow( @@ -87,9 +67,32 @@ makeSuite('AToken: Transfer', (testEnv: TestEnv) => { users[1].address ); + const userReserveData = await helpersContract.getUserReserveData(weth.address, users[1].address); + + expect(userReserveData.currentStableDebt.toString()).to.be.eq(ethers.utils.parseEther('0.1')); + }); + + it('User 1 tries to transfer all the DAI used as collateral back to user 0 (revert expected)', async () => { + const {users, pool, aDai, dai, weth} = testEnv; + + const aDAItoTransfer = await convertToCurrencyDecimals(dai.address, '1000'); + await expect( aDai.connect(users[1].signer).transfer(users[0].address, aDAItoTransfer), TRANSFER_NOT_ALLOWED ).to.be.revertedWith(TRANSFER_NOT_ALLOWED); }); + + it('User 1 tries to transfer a small amount of DAI used as collateral back to user 0', async () => { + + const {users, pool, aDai, dai, weth} = testEnv; + + const aDAItoTransfer = await convertToCurrencyDecimals(dai.address, '100'); + + await aDai.connect(users[1].signer).transfer(users[0].address, aDAItoTransfer); + + const user0Balance = await aDai.balanceOf(users[0].address); + + expect(user0Balance.toString()).to.be.eq(aDAItoTransfer.toString()); + }); });