Block addqt above auction price

src/base/Pool.sol

@@ -58,7 +58,8 @@ import {
 import {
  _revertIfAuctionDebtLocked,
  _revertIfAuctionClearable,
- _revertAfterExpiry
+ _revertAfterExpiry,
+ _revertIfAuctionPriceBelow
 } from '../libraries/helpers/RevertsHelper.sol';
 
 import { Buckets } from '../libraries/internal/Buckets.sol';
@@ -158,6 +159,8 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
 
  _revertIfAuctionClearable(auctions, loans);
 
+ _revertIfAuctionPriceBelow(index_, auctions);
+
  PoolState memory poolState = _accruePoolInterest();
 
  // round to token precision
@@ -192,6 +195,8 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
 
  _revertIfAuctionClearable(auctions, loans);
 
+ _revertIfAuctionPriceBelow(toIndex_, auctions);
+
  PoolState memory poolState = _accruePoolInterest();
 
  _revertIfAuctionDebtLocked(deposits, poolState.t0DebtInAuction, fromIndex_, poolState.inflator);
@@ -373,23 +378,9 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
  function withdrawBonds(
  address recipient_,
  uint256 maxAmount_
- ) external override nonReentrant {
- uint256 claimable = auctions.kickers[msg.sender].claimable;
-
- // the amount to claim is constrained by the claimable balance of sender
- // claiming escrowed bonds is not constraiend by the pool balance
- maxAmount_ = Maths.min(maxAmount_, claimable);
-
- // revert if no amount to claim
- if (maxAmount_ == 0) revert InsufficientLiquidity();
-
- // decrement total bond escrowed
- auctions.totalBondEscrowed -= maxAmount_;
- auctions.kickers[msg.sender].claimable -= maxAmount_;
-
- emit BondWithdrawn(msg.sender, recipient_, maxAmount_);
-
- _transferQuoteToken(recipient_, maxAmount_);
+ ) external override nonReentrant returns (uint256 withdrawnAmount_) {
+ withdrawnAmount_ = KickerActions.withdrawBonds(auctions, recipient_, maxAmount_);
+ _transferQuoteToken(recipient_, withdrawnAmount_);
  }
 
  /*********************************/
@@ -825,25 +816,9 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
 
  /// @inheritdoc IPoolState
  function debtInfo() external view returns (uint256, uint256, uint256, uint256) {
- uint256 t0Debt = poolBalances.t0Debt;
- uint256 inflator = inflatorState.inflator;
-
- return (
- Maths.ceilWmul(
- t0Debt,
- PoolCommons.pendingInflator(
- inflator,
- inflatorState.inflatorUpdate,
- interestState.interestRate
- )
- ),
- Maths.ceilWmul(t0Debt, inflator),
- Maths.ceilWmul(poolBalances.t0DebtInAuction, inflator),
- interestState.t0Debt2ToCollateral
- );
+ return PoolCommons.debtInfo(poolBalances, inflatorState, interestState);
  }
 
-
  /// @inheritdoc IPoolDerivedState
  function depositUpToIndex(uint256 index_) external view override returns (uint256) {
  return Deposits.prefixSum(deposits, index_);

src/interfaces/pool/commons/IPoolErrors.sol

@@ -10,6 +10,10 @@ interface IPoolErrors {
  /*** Common Pool Errors ***/
  /**************************/
 
+ /**
+ * @notice Adding liquidity above current auction price.
+ */
+ error AddAboveAuctionPrice();
  /**
  * @notice `LP` allowance is already set by the owner.
  */

src/interfaces/pool/commons/IPoolKickerActions.sol

@@ -35,11 +35,12 @@ interface IPoolKickerActions {
  * @notice Called by kickers to withdraw their auction bonds (the amount of quote tokens that are not locked in active auctions).
  * @param recipient_ Address to receive claimed bonds amount.
  * @param maxAmount_ The max amount to withdraw from auction bonds (`WAD` precision). Constrained by claimable amounts and liquidity.
+ * @return withdrawnAmount_ The amount withdrawn (`WAD` precision).
  */
  function withdrawBonds(
  address recipient_,
  uint256 maxAmount_
- ) external;
+ ) external returns (uint256 withdrawnAmount_);
 
  /***********************/
  /*** Reserve Auction ***/

src/libraries/external/KickerActions.sol

@@ -78,10 +78,11 @@ library KickerActions {
  /**************/
 
  // See `IPoolEvents` for descriptions
+ event BondWithdrawn(address indexed kicker, address indexed reciever, uint256 amount);
+ event BucketBankruptcy(uint256 indexed index, uint256 lpForfeited);
  event Kick(address indexed borrower, uint256 debt, uint256 collateral, uint256 bond);
- event RemoveQuoteToken(address indexed lender, uint256 indexed price, uint256 amount, uint256 lpRedeemed, uint256 lup);
  event KickReserveAuction(uint256 claimableReservesRemaining, uint256 auctionPrice, uint256 currentBurnEpoch);
- event BucketBankruptcy(uint256 indexed index, uint256 lpForfeited);
+ event RemoveQuoteToken(address indexed lender, uint256 indexed price, uint256 amount, uint256 lpRedeemed, uint256 lup);
 
  /**************/
  /*** Errors ***/
@@ -242,6 +243,27 @@ library KickerActions {
  );
  }
 
+ function withdrawBonds(
+ AuctionsState storage auctions_,
+ address recipient_,
+ uint256 maxAmount_
+ ) external returns (uint256 amount_) {
+ uint256 claimable = auctions_.kickers[msg.sender].claimable;
+
+ // the amount to claim is constrained by the claimable balance of sender
+ // claiming escrowed bonds is not constraiend by the pool balance
+ amount_ = Maths.min(maxAmount_, claimable);
+
+ // revert if no amount to claim
+ if (amount_ == 0) revert InsufficientLiquidity();
+
+ // decrement total bond escrowed
+ auctions_.totalBondEscrowed -= amount_;
+ auctions_.kickers[msg.sender].claimable -= amount_;
+
+ emit BondWithdrawn(msg.sender, recipient_, amount_);
+ }
+
  /***************************/
  /*** Internal Functions ***/
  /***************************/
@@ -410,7 +432,6 @@ library KickerActions {
  // record liquidation info
  liquidation_.kicker = msg.sender;
  liquidation_.kickTime = uint96(block.timestamp);
- liquidation_.referencePrice = SafeCast.toUint96(referencePrice_);
  liquidation_.bondSize = SafeCast.toUint160(bondSize_);
  liquidation_.bondFactor = SafeCast.toUint96(bondFactor_);
  liquidation_.neutralPrice = SafeCast.toUint96(neutralPrice_);
@@ -422,11 +443,14 @@ library KickerActions {
  // update auctions queue
  if (auctions_.head != address(0)) {
  // other auctions in queue, liquidation doesn't exist or overwriting.
- auctions_.liquidations[auctions_.tail].next = borrowerAddress_;
- liquidation_.prev = auctions_.tail;
+ address tail = auctions_.tail;
+ auctions_.liquidations[tail].next = borrowerAddress_;
+ liquidation_.prev = tail;
+ liquidation_.referencePrice = SafeCast.toUint96(Maths.max(referencePrice_, auctions_.liquidations[tail].referencePrice));
  } else {
  // first auction in queue
  auctions_.head = borrowerAddress_;
+ liquidation_.referencePrice = SafeCast.toUint96(referencePrice_);
  }
  // update liquidation with the new ordering
  auctions_.tail = borrowerAddress_;

src/libraries/external/PoolCommons.sol

@@ -9,7 +9,14 @@ import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
 
 
-import { InterestState, EmaState, PoolState, DepositsState } from '../../interfaces/pool/commons/IPoolState.sol';
+import { 
+ DepositsState, 
+ EmaState, 
+ InflatorState,
+ InterestState, 
+ PoolBalancesState, 
+ PoolState 
+} from '../../interfaces/pool/commons/IPoolState.sol';
 import { IERC3156FlashBorrower } from '../../interfaces/pool/IERC3156FlashBorrower.sol';
 
 import { 
@@ -429,6 +436,38 @@ library PoolCommons {
  /*** View Functions ***/
  /**********************/
 
+ /**
+ * @notice Calculates pool related debt values.
+ * @param poolBalances_ Pool debt
+ * @param inflatorState_ Interest inflator and last update time
+ * @param interestState_ Interest rate and t0Debt2ToCollateral accumulator
+ * @return Current amount of debt owed by borrowers in pool.
+ * @return Debt owed by borrowers based on last inflator snapshot.
+ * @return Total amount of debt in auction.
+ * @return t0debt accross all borrowers divided by their collateral, used in determining a collateralization weighted debt. 
+ */
+ function debtInfo(
+ PoolBalancesState memory poolBalances_,
+ InflatorState memory inflatorState_,
+ InterestState memory interestState_
+ ) external view returns (uint256, uint256, uint256, uint256) {
+ uint256 t0Debt = poolBalances_.t0Debt;
+ uint256 inflator = inflatorState_.inflator;
+
+ return (
+ Maths.ceilWmul(
+ t0Debt,
+ Maths.wmul(
+ inflator,
+ PRBMathUD60x18.exp((interestState_.interestRate * (block.timestamp - inflatorState_.inflatorUpdate)) / 365 days)
+ )
+ ),
+ Maths.ceilWmul(t0Debt, inflator),
+ Maths.ceilWmul(poolBalances_.t0DebtInAuction, inflator),
+ interestState_.t0Debt2ToCollateral
+ );
+ }
+
  /**
  * @notice Calculates pool interest factor for a given interest rate and time elapsed since last inflator update.
  * @param interestRate_ Current pool interest rate.

src/libraries/helpers/RevertsHelper.sol

@@ -10,7 +10,7 @@ import {
  PoolBalancesState
 } from '../../interfaces/pool/commons/IPoolState.sol';
 
-import { _minDebtAmount, _priceAt } from './PoolHelper.sol';
+import { _minDebtAmount, _priceAt, _auctionPrice } from './PoolHelper.sol';
 
 import { Loans } from '../internal/Loans.sol';
 import { Deposits } from '../internal/Deposits.sol';
@@ -23,6 +23,7 @@ import { Maths } from '../internal/Maths.sol';
  error LimitIndexExceeded();
  error RemoveDepositLockedByAuctionDebt();
  error TransactionExpired();
+ error AddAboveAuctionPrice();
 
  /**
  * @notice Called by `LP` removal functions assess whether or not `LP` is locked.
@@ -75,6 +76,24 @@ import { Maths } from '../internal/Maths.sol';
  if (newPrice_ < _priceAt(limitIndex_)) revert LimitIndexExceeded();
  }
 
+/**
+ * @notice Check if provided price is above current auction price.
+ * @notice Prevents manipulative deposir and arb takes.
+ * @dev Reverts with `AddAboveAuctionPrice` if price is above head of auction queue.
+ * @param index_ Identifies bucket price to be compared with current auction price.
+ * @param auctions_ Auctions data.
+ */
+ function _revertIfAuctionPriceBelow(
+ uint256 index_,
+ AuctionsState storage auctions_
+ ) view {
+ address head = auctions_.head;
+ if (head != address(0)) {
+ uint256 auctionPrice = _auctionPrice(auctions_.liquidations[head].referencePrice, auctions_.liquidations[head].kickTime);
+ if (_priceAt(index_) >= auctionPrice) revert AddAboveAuctionPrice();
+ }
+ }
+
  /**
  * @notice Check if expiration provided by user has met or exceeded current block height timestamp.
  * @notice Prevents stale transactions interacting with the pool at potentially unfavorable prices.

tests/INVARIANTS.md

@@ -25,6 +25,7 @@
 - **A5**: for each `Liquidation` recorded in liquidation mapping (`AuctionsState.liquidations`) the kicker address (`Liquidation.kicker`) has a locked balance (`Kicker.locked`) equal or greater than liquidation bond size (`Liquidation.bondSize`) 
 - **A7**: total bond escrowed accumulator (`AuctionsState.totalBondEscrowed`) should increase when auction is kicked with the difference needed to cover the bond and should decrease only when kicker bonds withdrawn (`Pool.withdrawBonds`). Claimable bonds should be available for withdrawal from pool at any time. 
 - **A8**: Upon a take/arbtake/deposittake the kicker reward <= borrower penalty
+- **A9**: reference prices in liquidation queue shall not decrease
 
 ## Loans
 - **L1**: for each `Loan` in loans array (`LoansState.loans`) starting from index 1, the corresponding address (`Loan.borrower`) is not `0x`, the threshold price (`Loan.thresholdPrice`) is different than 0 and the id mapped in indices mapping (`LoansState.indices`) equals index of loan in loans array. 

tests/forge/invariants/base/LiquidationInvariants.t.sol

@@ -21,6 +21,7 @@ abstract contract LiquidationInvariants is BasicInvariants {
  _invariant_A5();
  _invariant_A7();
  _invariant_A8();
+ // _invariant_A9(); // TODO: uncomment once other invariant issues are sorted
  }
 
  /// @dev checks sum of all borrower's t0debt is equals to total pool t0debtInAuction
@@ -140,6 +141,16 @@ abstract contract LiquidationInvariants is BasicInvariants {
 
  require(kickerReward <= borrowerPenalty, "Auction Invariant A8");
  }
+
+ /// @dev reference prices in liquidation queue shall not decrease
+ function _invariant_A9() internal view {
+ (,,,, uint256 lastReferencePrice,,, address nextBorrower,,) = _pool.auctionInfo(address(0));
+ while (nextBorrower != address(0)) {
+ (,,,, uint256 referencePrice,,,,,) = _pool.auctionInfo(nextBorrower);
+ require(lastReferencePrice <= referencePrice, "Auction Invariant A9");
+ lastReferencePrice = referencePrice;
+ }
+ }
 
  function invariant_call_summary() public virtual override useCurrentTimestamp {
  console.log("\nCall Summary\n");

tests/forge/invariants/base/handlers/unbounded/BaseHandler.sol

@@ -319,7 +319,8 @@ abstract contract BaseHandler is Test {
  err == keccak256(abi.encodeWithSignature("ReserveAuctionTooSoon()")) ||
  err == keccak256(abi.encodeWithSignature("NoReserves()")) ||
  err == keccak256(abi.encodeWithSignature("ZeroThresholdPrice()")) ||
- err == keccak256(abi.encodeWithSignature("NoReservesAuction()")),
+ err == keccak256(abi.encodeWithSignature("NoReservesAuction()")) ||
+ err == keccak256(abi.encodeWithSignature("AddAboveAuctionPrice()")),
  "Unexpected revert error"
  );
  }

tests/forge/unit/ERC20Pool/ERC20DSTestPlus.sol

@@ -820,6 +820,15 @@ abstract contract ERC20DSTestPlus is DSTestPlus, IERC20PoolEvents {
  _pool.moveQuoteToken(amount, fromIndex, toIndex, type(uint256).max);
  }
 
+ function _assertAddAboveAuctionPriceRevert(
+ address from,
+ uint256 amount,
+ uint256 index
+ ) internal {
+ changePrank(from);
+ vm.expectRevert(IPoolErrors.AddAboveAuctionPrice.selector);
+ _pool.addQuoteToken(amount, index, type(uint256).max);
+ }
 }
 
 abstract contract ERC20HelperContract is ERC20DSTestPlus {

tests/forge/unit/ERC20Pool/ERC20PoolDebtExceedsDeposit.t.sol

@@ -178,7 +178,7 @@ contract ERC20PoolDebtExceedsDepositTest is ERC20HelperContract {
  totalBondEscrowed: 1.104560604152777078 * 1e18,
  auctionPrice: 52.807937446000777584 * 1e18,
  debtInAuction: 98.794903846153846199 * 1e18,
- thresholdPrice: 94.999437626898539235 * 1e18,
+ thresholdPrice: 94.995099852071005961 * 1e18,
  neutralPrice: 105.615874892001555166 * 1e18
  })
  );
@@ -363,7 +363,7 @@ contract ERC20PoolDebtExceedsDepositTest is ERC20HelperContract {
  totalBondEscrowed: 11_179.675302295250711919 * 1e18,
  auctionPrice: 50.449052405478872444 * 1e18,
  debtInAuction: 999_940.55769230769276876 * 1e18,
- thresholdPrice: 96.152612442506987001 * 1e18,
+ thresholdPrice: 96.148130547337278151 * 1e18,
  neutralPrice: 106.897818338005788835 * 1e18
  })
  );