feat: mix bytes audit

.solhint.json

@@ -21,7 +21,7 @@
     "code-complexity": ["error", 15],
     "function-max-lines": ["error", 80],
     "max-line-length": ["warn", 120],
-    "max-states-count": ["error", 15],
+    "max-states-count": ["error", 16],
     "no-empty-blocks": "warn",
     "no-unused-vars": "error",
     "payable-fallback": "off",

script/Deploy.sol

@@ -44,6 +44,7 @@ contract Deploy is Config {
                 0,
                 0,
                 0,
+                0,
                 100,
                 selfPeggingAssetBeacon,
                 lpTokenBeacon,

script/Pool.sol

@@ -20,10 +20,12 @@ contract Pool is Config {
             tokenB: usdt,
             tokenAType: SelfPeggingAssetFactory.TokenType.Standard,
             tokenAOracle: address(0),
-            tokenAFunctionSig: "",
+            tokenARateFunctionSig: "",
+            tokenADecimalsFunctionSig: "",
             tokenBType: SelfPeggingAssetFactory.TokenType.Standard,
             tokenBOracle: address(0),
-            tokenBFunctionSig: ""
+            tokenBRateFunctionSig: "",
+            tokenBDecimalsFunctionSig: ""
         });
 
         vm.recordLogs();

src/LPToken.sol

@@ -33,6 +33,11 @@
      */
     uint256 public constant BUFFER_DENOMINATOR = 10 ** 10;
 
+    /**
+     * @dev Constant value representing the number of dead shares.
+     */
+    uint256 public constant NUMBER_OF_DEAD_SHARES = 1000;
+
     /**
      * @dev The total amount of shares.
      */
@@ -56,7 +61,7 @@
     /**
      * @dev The mapping of account allowances.
      */
-    mapping(address => mapping(address => uint256)) public allowances;
+    mapping(address => mapping(address => uint256)) private allowances;
 
     /**
      * @dev The mapping of pools.
@@ -83,6 +88,11 @@
      */
     string internal tokenSymbol;
 
+    /**
+     * @dev The bad debt of the buffer.
+     */
+    uint256 public bufferBadDebt;
+
     /**
      * @notice Emitted when shares are transferred.
      */
@@ -128,6 +138,11 @@
      */
     event BufferDecreased(uint256, uint256);
 
+    /**
+     * @notice Emitted when there is negative rebase.
+     */
+    event NegativelyRebased(uint256, uint256);
+
     /**
      * @notice Emitted when the symbol is modified.
      */
@@ -172,6 +187,9 @@
     /// @notice Error thrown when the pool is not found.
     error PoolNotFound();
 
+    /// @notice Error thrown when the supply is insufficient.
+    error InsufficientSupply();
+
     function initialize(string memory _name, string memory _symbol) public initializer {
         tokenName = _name;
         tokenSymbol = _symbol;
@@ -222,7 +240,7 @@
      * @dev Mints shares for the `_account` and transfers them to the `_account`.
      */
     function mintShares(address _account, uint256 _tokenAmount) external {
         require(pools[msg.sender], NoPool());
         _mintShares(_account, _tokenAmount);
     }
 
@@ -308,7 +326,7 @@
      */
     function decreaseAllowance(address _spender, uint256 _subtractedValue) external returns (bool) {
         uint256 currentAllowance = allowances[msg.sender][_spender];
         require(currentAllowance >= _subtractedValue, AllowanceBelowZero());
         _approve(msg.sender, _spender, currentAllowance - _subtractedValue);
         return true;
     }
@@ -318,7 +336,7 @@
      * @notice This function is called by the owner to set the buffer rate.
      */
     function setBuffer(uint256 _buffer) external onlyOwner {
         require(_buffer < BUFFER_DENOMINATOR, OutOfRange());
         bufferPercent = _buffer;
         emit SetBufferPercent(_buffer);
     }
@@ -336,31 +354,56 @@
      * the total supply of LPToken by the staking rewards and the swap fee.
      */
     function addTotalSupply(uint256 _amount) external {
         require(pools[msg.sender], NoPool());
         require(_amount != 0, InvalidAmount());
+
+        if (bufferBadDebt >= _amount) {
+            bufferBadDebt -= _amount;
+            bufferAmount += _amount;
+            emit BufferIncreased(_amount, bufferAmount);
+            return;
+        }
+
+        uint256 prevAmount = _amount;
+        uint256 prevBufferBadDebt = bufferBadDebt;
+        _amount = _amount - bufferBadDebt;
+        bufferAmount += bufferBadDebt;
+        bufferBadDebt = 0;
+
         uint256 _deltaBuffer = (bufferPercent * _amount) / BUFFER_DENOMINATOR;
         uint256 actualAmount = _amount - _deltaBuffer;
 
         totalSupply += actualAmount;
         totalRewards += actualAmount;
         bufferAmount += _deltaBuffer;
 
-        emit BufferIncreased(_deltaBuffer, bufferAmount);
-        emit RewardsMinted(_amount, actualAmount);
+        emit BufferIncreased(_deltaBuffer + prevBufferBadDebt, bufferAmount);
+        emit RewardsMinted(prevAmount, actualAmount);
     }
 
     /**
      * @notice This function is called only by a stableSwap pool to decrease
      * the total supply of LPToken by lost amount.
+     * @param _amount The amount of lost tokens.
+     * @param isBuffer The flag to indicate whether to use the buffer or not.
+     * @param withDebt The flag to indicate whether to add the lost amount to the buffer bad debt or not.
      */
-    function removeTotalSupply(uint256 _amount) external {
+    function removeTotalSupply(uint256 _amount, bool isBuffer, bool withDebt) external {
         require(pools[msg.sender], NoPool());
         require(_amount != 0, InvalidAmount());
-        require(_amount <= bufferAmount, InsufficientBuffer());
 
-        bufferAmount -= _amount;
-
-        emit BufferDecreased(_amount, bufferAmount);
+        if (isBuffer) {
+            require(_amount <= bufferAmount, InsufficientBuffer());
+            bufferAmount -= _amount;
+            if (withDebt) {
+                bufferBadDebt += _amount;
+            }
+            emit BufferDecreased(_amount, bufferAmount);
+        } else {
+            require(_amount <= totalSupply, InsufficientSupply());
+            totalSupply -= _amount;
+            emit NegativelyRebased(_amount, totalSupply);
+        }
     }
 
     /**
@@ -368,7 +411,7 @@
      * the total supply of LPToken
      */
     function addBuffer(uint256 _amount) external {
         require(pools[msg.sender], NoPool());
         require(_amount != 0, InvalidAmount());
 
         bufferAmount += _amount;
@@ -537,7 +580,9 @@
         if (totalSupply != 0 && totalShares != 0) {
             _sharesAmount = getSharesByPeggedToken(_tokenAmount);
         } else {
-            _sharesAmount = _tokenAmount;
+            _sharesAmount = totalSupply + _tokenAmount - NUMBER_OF_DEAD_SHARES;
+            shares[address(0)] = NUMBER_OF_DEAD_SHARES;
+            totalShares += NUMBER_OF_DEAD_SHARES;
         }
         shares[_recipient] += _sharesAmount;
         totalShares += _sharesAmount;