105 lines
4.0 KiB
Solidity
105 lines
4.0 KiB
Solidity
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/*
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* @source: https://etherscan.io/address/0x741f1923974464efd0aa70e77800ba5d9ed18902#code
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* @vulnerable_at_lines: 91
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*/
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pragma solidity ^0.4.19;
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/*
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* This is a distributed lottery that chooses random addresses as lucky addresses. If these
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* participate, they get the jackpot: 7 times the price of their bet.
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* Of course one address can only win once. The owner regularly reseeds the secret
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* seed of the contract (based on which the lucky addresses are chosen), so if you did not win,
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* just wait for a reseed and try again!
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*
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* Jackpot chance: 1 in 8
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* Ticket price: Anything larger than (or equal to) 0.1 ETH
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* Jackpot size: 7 times the ticket price
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*
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* HOW TO PARTICIPATE: Just send any amount greater than (or equal to) 0.1 ETH to the contract's address
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* Keep in mind that your address can only win once
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*
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* If the contract doesn't have enough ETH to pay the jackpot, it sends the whole balance.
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https://www.reddit.com/r/ethdev/comments/7wp363/how_does_this_honeypot_work_it_seems_like_a/
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*/
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contract OpenAddressLottery{
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struct SeedComponents{
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uint component1;
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uint component2;
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uint component3;
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uint component4;
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}
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address owner; //address of the owner
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uint private secretSeed; //seed used to calculate number of an address
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uint private lastReseed; //last reseed - used to automatically reseed the contract every 1000 blocks
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uint LuckyNumber = 7; //if the number of an address equals 7, it wins
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mapping (address => bool) winner; //keeping track of addresses that have already won
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function OpenAddressLottery() {
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owner = msg.sender;
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reseed(SeedComponents((uint)(block.coinbase), block.difficulty, block.gaslimit, block.timestamp)); //generate a quality random seed
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}
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function participate() payable {
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if(msg.value<0.1 ether)
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return; //verify ticket price
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// make sure he hasn't won already
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require(winner[msg.sender] == false);
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if(luckyNumberOfAddress(msg.sender) == LuckyNumber){ //check if it equals 7
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winner[msg.sender] = true; // every address can only win once
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uint win=msg.value*7; //win = 7 times the ticket price
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if(win>this.balance) //if the balance isnt sufficient...
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win=this.balance; //...send everything we've got
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msg.sender.transfer(win);
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}
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if(block.number-lastReseed>1000) //reseed if needed
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reseed(SeedComponents((uint)(block.coinbase), block.difficulty, block.gaslimit, block.timestamp)); //generate a quality random seed
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}
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function luckyNumberOfAddress(address addr) constant returns(uint n){
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// calculate the number of current address - 1 in 8 chance
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n = uint(keccak256(uint(addr), secretSeed)[0]) % 8;
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}
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function reseed(SeedComponents components) internal {
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secretSeed = uint256(keccak256(
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components.component1,
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components.component2,
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components.component3,
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components.component4
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)); //hash the incoming parameters and use the hash to (re)initialize the seed
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lastReseed = block.number;
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}
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function kill() {
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require(msg.sender==owner);
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selfdestruct(msg.sender);
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}
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function forceReseed() { //reseed initiated by the owner - for testing purposes
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require(msg.sender==owner);
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// <yes> <report> OTHER - uninitialized storage
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SeedComponents s;
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s.component1 = uint(msg.sender);
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s.component2 = uint256(block.blockhash(block.number - 1));
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s.component3 = block.difficulty*(uint)(block.coinbase);
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s.component4 = tx.gasprice * 7;
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reseed(s); //reseed
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}
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function () payable { //if someone sends money without any function call, just assume he wanted to participate
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if(msg.value>=0.1 ether && msg.sender!=owner) //owner can't participate, he can only fund the jackpot
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participate();
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}
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}
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