smartbugs-curated/dataset/bad_randomness/lottery.sol

69 lines
1.7 KiB
Solidity

/*
* @article: https://blog.positive.com/predicting-random-numbers-in-ethereum-smart-contracts-e5358c6b8620
* @source: https://etherscan.io/address/0x80ddae5251047d6ceb29765f38fed1c0013004b7#code
* @vulnerable_at_lines: 38,42
* @author: -
*/
//added pragma version
pragma solidity ^0.4.0;
contract Lottery {
event GetBet(uint betAmount, uint blockNumber, bool won);
struct Bet {
uint betAmount;
uint blockNumber;
bool won;
}
address private organizer;
Bet[] private bets;
// Create a new lottery with numOfBets supported bets.
function Lottery() {
organizer = msg.sender;
}
// Fallback function returns ether
function() {
throw;
}
// Make a bet
function makeBet() {
// Won if block number is even
// (note: this is a terrible source of randomness, please don't use this with real money)
// <yes> <report> BAD_RANDOMNESS
bool won = (block.number % 2) == 0;
// Record the bet with an event
// <yes> <report> BAD_RANDOMNESS
bets.push(Bet(msg.value, block.number, won));
// Payout if the user won, otherwise take their money
if(won) {
if(!msg.sender.send(msg.value)) {
// Return ether to sender
throw;
}
}
}
// Get all bets that have been made
function getBets() {
if(msg.sender != organizer) { throw; }
for (uint i = 0; i < bets.length; i++) {
GetBet(bets[i].betAmount, bets[i].blockNumber, bets[i].won);
}
}
// Suicide :(
function destroy() {
if(msg.sender != organizer) { throw; }
suicide(organizer);
}
}