457 lines
12 KiB
Markdown
457 lines
12 KiB
Markdown
# 🔒 Slither 安全审计修复指南
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## 📌 修复优先级
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- **P0 (立即修复)**: 高危漏洞,可能导致资金损失或合约被破坏
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- **P1 (尽快修复)**: 中危问题,可能导致精度损失或逻辑错误
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- **P2 (建议修复)**: 低危问题,影响代码质量和可维护性
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---
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## 🔴 P0: 高危问题 (必须立即修复)
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### 1. ⚠️ 未保护的初始化函数 (最严重!)
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**问题**: 所有可升级合约的 `initialize` 函数缺少 `initializer` 修饰符
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**风险**: 攻击者可以调用 `upgradeToAndCall` 删除合约!
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**受影响的合约**:
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- YTAssetFactory.sol
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- YTAssetVault.sol
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- YTPoolManager.sol
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- YTVault.sol
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- YTPriceFeed.sol
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- YTRewardRouter.sol
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- USDY.sol
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- WUSD.sol
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- YTLPToken.sol
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#### ✅ 修复方案
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**YTAssetFactory.sol (Line 52-63)**
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```solidity
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// ❌ 修复前
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function initialize(
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address _vaultImplementation,
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uint256 _defaultHardCap
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) external initializer {
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if (_vaultImplementation == address(0)) revert InvalidAddress();
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__Ownable_init(msg.sender);
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__UUPSUpgradeable_init();
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vaultImplementation = _vaultImplementation;
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defaultHardCap = _defaultHardCap;
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}
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// ✅ 修复后 (已经有 initializer 修饰符,这个合约是正确的)
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// 但需要确保其他合约也添加了
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```
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**YTAssetVault.sol (Line 125-154) - 需要修复**
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```solidity
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// ❌ 修复前
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function initialize(
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string memory _name,
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string memory _symbol,
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address _manager,
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uint256 _hardCap,
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address _wusd,
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uint256 _redemptionTime,
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uint256 _initialWusdPrice,
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uint256 _initialYtPrice
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) external initializer {
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// ... 初始化代码
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}
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// ✅ 修复后 (已正确)
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// 这个合约已经有 initializer 修饰符了
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```
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**实际问题**: 检查代码发现大部分合约已经使用了 `initializer` 修饰符。
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但 Slither 可能是在检测 **proxy 合约的部署安全性**。
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**额外保护**: 在实现合约的构造函数中添加 `_disableInitializers()`
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```solidity
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/// @custom:oz-upgrades-unsafe-allow constructor
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constructor() {
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_disableInitializers();
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}
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```
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这样可以防止实现合约被直接初始化。
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---
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### 2. ⚠️ 任意 from 地址的 transferFrom
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**位置**: `YTPoolManager.sol` Line 158
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**问题代码**:
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```solidity
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function _addLiquidity(
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address _fundingAccount, // ⚠️ 可以是任意地址
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address _account,
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address _token,
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uint256 _amount,
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uint256 _minUsdy,
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uint256 _minYtLP
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) private returns (uint256) {
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// ...
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IERC20(_token).safeTransferFrom(_fundingAccount, ytVault, _amount); // ⚠️ 危险!
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// ...
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}
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```
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**风险**: 如果 `_fundingAccount` 可以被恶意控制,可能导致未授权的代币转移。
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#### ✅ 修复方案
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**方案 1: 限制调用者 (推荐)**
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```solidity
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function _addLiquidity(
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address _fundingAccount,
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address _account,
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address _token,
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uint256 _amount,
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uint256 _minUsdy,
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uint256 _minYtLP
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) private returns (uint256) {
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if (_amount == 0) revert InvalidAmount();
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// ✅ 添加: 确保只有授权的 handler 或用户本人可以使用其账户
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if (_fundingAccount != msg.sender && !isHandler[msg.sender]) {
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revert Forbidden();
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}
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uint256 aumInUsdy = getAumInUsdy(true);
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uint256 ytLPSupply = IERC20(ytLP).totalSupply();
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IERC20(_token).safeTransferFrom(_fundingAccount, ytVault, _amount);
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// ... 后续逻辑
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}
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```
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**方案 2: 使用白名单**
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```solidity
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// 添加状态变量
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mapping(address => bool) public approvedFundingAccounts;
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// 添加管理函数
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function setApprovedFundingAccount(address _account, bool _approved) external onlyGov {
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approvedFundingAccounts[_account] = _approved;
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}
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// 在 _addLiquidity 中检查
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function _addLiquidity(...) private returns (uint256) {
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if (!approvedFundingAccounts[_fundingAccount] && _fundingAccount != msg.sender) {
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revert UnauthorizedFundingAccount();
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}
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// ...
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}
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```
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---
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## 🟠 P1: 中危问题 (尽快修复)
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### 3. 重入漏洞
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**位置**: `YTVault.sol` Line 331-335
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**问题代码**:
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```solidity
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function sellUSDY(address _token, address _receiver)
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external
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onlyPoolManager
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nonReentrant // ✅ 已经有 nonReentrant,但顺序不对
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notInEmergency
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returns (uint256)
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{
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// ... 前面的逻辑
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// ❌ 外部调用
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IUSDY(usdy).burn(address(this), usdyAmount);
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// ❌ 之后更新状态
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IERC20(_token).safeTransfer(_receiver, amountOut);
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_updateTokenBalance(_token); // 状态更新在外部调用后!
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}
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```
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**分析**: 虽然已经有 `nonReentrant` 修饰符,但 Slither 仍然报告是因为:
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1. `_updateTokenBalance` 在外部调用后执行
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2. 如果 `_receiver` 是恶意合约,可能在 `safeTransfer` 回调中做些什么
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#### ✅ 修复方案
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**遵循 CEI 模式 (Checks-Effects-Interactions)**
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```solidity
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function sellUSDY(address _token, address _receiver)
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external
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onlyPoolManager
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nonReentrant
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notInEmergency
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returns (uint256)
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{
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if (!whitelistedTokens[_token]) revert TokenNotWhitelisted();
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if (!isSwapEnabled) revert SwapDisabled();
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uint256 usdyAmount = _transferIn(usdy);
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if (usdyAmount == 0) revert InvalidAmount();
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uint256 price = _getPrice(_token, true);
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uint256 redemptionAmount = usdyAmount * PRICE_PRECISION / price;
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redemptionAmount = _adjustForDecimals(redemptionAmount, usdy, _token);
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if (redemptionAmount == 0) revert InvalidAmount();
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uint256 feeBasisPoints = _getSwapFeeBasisPoints(usdy, _token, redemptionAmount);
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uint256 amountOut = redemptionAmount * (BASIS_POINTS_DIVISOR - feeBasisPoints) / BASIS_POINTS_DIVISOR;
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if (amountOut == 0) revert InvalidAmount();
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if (poolAmounts[_token] < amountOut) revert InsufficientPool();
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uint256 usdyAmountOut = amountOut * price / PRICE_PRECISION;
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usdyAmountOut = _adjustForDecimals(usdyAmountOut, _token, usdy);
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// ✅ 1. Effects: 先更新所有状态
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_decreasePoolAmount(_token, amountOut);
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_decreaseUsdyAmount(_token, usdyAmountOut);
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// ✅ 预先更新 tokenBalance (模拟转出后的余额)
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uint256 currentBalance = IERC20(_token).balanceOf(address(this));
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tokenBalances[_token] = currentBalance - amountOut;
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// ✅ 2. Interactions: 最后进行外部调用
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IUSDY(usdy).burn(address(this), usdyAmount);
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IERC20(_token).safeTransfer(_receiver, amountOut);
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// ✅ 3. 验证最终余额 (可选,增强安全性)
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uint256 finalBalance = IERC20(_token).balanceOf(address(this));
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require(finalBalance == tokenBalances[_token], "Balance mismatch");
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emit RemoveLiquidity(_receiver, _token, usdyAmount, amountOut);
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return amountOut;
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}
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```
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---
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### 4. 先除后乘导致精度损失
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**位置**: 多处
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#### 问题 1: `Lending.sol` Line 343, 346
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```solidity
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// ❌ 修复前
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uint256 collateralValueUSD = (collateralAmount * assetPrice) / assetScale;
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uint256 discountedValue = (collateralValueUSD * assetConfig.liquidationFactor) / 1e18;
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// ✅ 修复后
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uint256 collateralValueUSD = (collateralAmount * assetPrice * assetConfig.liquidationFactor)
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/ (assetScale * 1e18);
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```
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#### 问题 2: `Lending.sol` Line 470, 479
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```solidity
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// ❌ 修复前
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uint256 assetPriceDiscounted = (assetPrice * (FACTOR_SCALE - discountFactor)) / FACTOR_SCALE;
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uint256 result = (basePrice * baseAmount * assetScale) / (assetPriceDiscounted * baseScale);
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// ✅ 修复后
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uint256 result = (basePrice * baseAmount * assetScale * FACTOR_SCALE)
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/ (assetPrice * (FACTOR_SCALE - discountFactor) * baseScale);
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```
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#### 问题 3: `YTVault.sol` Line 548, 552
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```solidity
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// ❌ 修复前
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uint256 averageDiff = (initialDiff + nextDiff) / 2;
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uint256 taxBps = _taxBasisPoints * averageDiff / targetAmount;
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// ✅ 修复后
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uint256 taxBps = _taxBasisPoints * (initialDiff + nextDiff) / (2 * targetAmount);
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```
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---
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## 🟡 P2: 低危/信息性问题
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### 5. 缺少事件发射
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```solidity
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// YTPoolManager.sol Line 112
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function setGov(address _gov) external onlyGov {
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if (_gov == address(0)) revert InvalidAddress();
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address oldGov = gov; // ✅ 添加
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gov = _gov;
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emit GovChanged(oldGov, _gov); // ✅ 添加事件
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}
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// ✅ 添加事件定义
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event GovChanged(address indexed oldGov, address indexed newGov);
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event PoolManagerChanged(address indexed oldManager, address indexed newManager);
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event AumAdjustmentChanged(uint256 addition, uint256 deduction);
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```
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### 6. 缺少零地址检查
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```solidity
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// YTAssetVault.sol Line 176
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function setManager(address _manager) external onlyFactory {
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require(_manager != address(0), "Zero address"); // ✅ 添加检查
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manager = _manager;
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emit ManagerSet(_manager);
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}
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// YTPriceFeed.sol Line 80
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function setWusdPriceSource(address _wusdPriceSource) external onlyGov {
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require(_wusdPriceSource != address(0), "Zero address"); // ✅ 添加检查
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wusdPriceSource = _wusdPriceSource;
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}
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```
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### 7. 忽略返回值
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```solidity
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// YTRewardRouter.sol Line 117
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// ❌ 修复前
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IERC20(_token).approve(ytPoolManager, _amount);
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// ✅ 修复后
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bool success = IERC20(_token).approve(ytPoolManager, _amount);
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require(success, "Approve failed");
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// 或者使用 SafeERC20
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IERC20(_token).safeApprove(ytPoolManager, _amount);
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```
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### 8. Solidity 版本统一
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```solidity
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// ❌ 修复前: 各个文件使用不同版本
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pragma solidity ^0.8.0;
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// ✅ 修复后: 统一使用
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pragma solidity ^0.8.20;
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```
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---
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## 📋 修复检查清单
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### P0 - 高危问题
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- [ ] 在所有实现合约添加 `_disableInitializers()` 到构造函数
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- [ ] 修复 `YTPoolManager._addLiquidity` 的任意 from 问题
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- [ ] 验证所有合约的 `initialize` 函数有 `initializer` 修饰符
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### P1 - 中危问题
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- [ ] 重构 `YTVault.sellUSDY` 遵循 CEI 模式
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- [ ] 修复所有先除后乘的精度问题
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- [ ] Lending._absorbInternal
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- [ ] Lending.quoteCollateral
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- [ ] YTVault.sellUSDY
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- [ ] YTVault.swap
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- [ ] YTVault.getFeeBasisPoints
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### P2 - 低危问题
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- [ ] 添加缺失的事件
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- [ ] 添加零地址检查
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- [ ] 修复忽略返回值的问题
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- [ ] 统一 Solidity 版本到 ^0.8.20
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---
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## 🧪 测试建议
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### 1. 初始化安全测试
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```solidity
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// test/security/InitializerTest.t.sol
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function testCannotReinitialize() public {
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vm.expectRevert();
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factory.initialize(address(vault), 1000);
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}
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function testCannotInitializeImplementation() public {
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YTAssetVault impl = new YTAssetVault();
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vm.expectRevert();
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impl.initialize("Test", "TST", address(this), 1000, address(0), 0, 0, 0);
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}
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```
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### 2. 重入攻击测试
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```solidity
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contract MaliciousReceiver {
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YTVault public vault;
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bool public attacked;
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function attack() external {
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// 尝试重入
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vault.sellUSDY(token, address(this));
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}
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// ERC20 回调
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function onERC20Received(...) external {
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if (!attacked) {
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attacked = true;
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vault.sellUSDY(token, address(this)); // 应该失败
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}
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}
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}
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function testReentrancyProtection() public {
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MaliciousReceiver attacker = new MaliciousReceiver(vault);
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vm.expectRevert("ReentrancyGuard: reentrant call");
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attacker.attack();
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}
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```
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### 3. 精度损失测试
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```solidity
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function testMathPrecision() public {
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uint256 price = 1e30;
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uint256 amount = 1e18;
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uint256 scale = 1e18;
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// 测试先除后乘 vs 先乘后除的差异
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uint256 result1 = (amount * price) / scale;
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uint256 result2 = amount * (price / scale);
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assertEq(result1, result2, "Precision loss detected");
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}
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```
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---
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## 📞 后续步骤
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1. **立即修复 P0 问题**
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2. **运行完整测试套件**
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3. **重新运行 Slither 验证修复**
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4. **考虑进行专业审计**
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```bash
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# 重新运行 Slither
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slither . --exclude-informational --exclude-low
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# 运行测试
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forge test -vvv
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# 生成覆盖率报告
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forge coverage
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```
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