merge with latest (1cef159) parity-bridge state
This commit is contained in:
Alexander Kolotov
parent
705d1e6196
commit
20acfe0c04
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@ -1,43 +1,59 @@
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pragma solidity ^0.4.15;
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pragma solidity ^0.4.17;
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library Authorities {
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function contains (address[] self, address value) internal pure returns (bool) {
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for (uint i = 0; i < self.length; i++) {
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if (self[i] == value) {
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/// general helpers.
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/// `internal` so they get compiled into contracts using them.
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library Helpers {
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/// returns whether `array` contains `value`.
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function addressArrayContains(address[] array, address value) internal pure returns (bool) {
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for (uint i = 0; i < array.length; i++) {
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if (array[i] == value) {
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return true;
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}
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}
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return false;
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}
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}
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/// Library used only to test Signer library via rpc calls
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library SignerTest {
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function signer (bytes signature, bytes message) public pure returns (address) {
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return Signer.signer(signature, message);
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// returns the digits of `inputValue` as a string.
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// example: `uintToString(12345678)` returns `"12345678"`
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function uintToString(uint inputValue) internal pure returns (string) {
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// figure out the length of the resulting string
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uint length = 0;
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uint currentValue = inputValue;
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do {
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length++;
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currentValue /= 10;
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} while (currentValue != 0);
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// allocate enough memory
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bytes memory result = new bytes(length);
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// construct the string backwards
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uint i = length - 1;
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currentValue = inputValue;
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do {
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result[i--] = byte(48 + currentValue % 10);
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currentValue /= 10;
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} while (currentValue != 0);
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return string(result);
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}
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}
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library Utils {
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function toString (uint256 v) internal pure returns (string str) {
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// it is used only for small numbers
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bytes memory reversed = new bytes(8);
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uint i = 0;
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while (v != 0) {
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uint remainder = v % 10;
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v = v / 10;
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reversed[i++] = byte(48 + remainder);
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}
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bytes memory s = new bytes(i);
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for (uint j = 0; j < i; j++) {
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s[j] = reversed[i - j - 1];
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}
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str = string(s);
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/// Library used only to test Helpers library via rpc calls
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library HelpersTest {
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function addressArrayContains(address[] array, address value) public pure returns (bool) {
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return Helpers.addressArrayContains(array, value);
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}
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function uintToString(uint256 inputValue) public pure returns (string str) {
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return Helpers.uintToString(inputValue);
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}
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}
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library Signer {
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function signer (bytes signature, bytes message) internal pure returns (address) {
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// helpers for message signing.
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// `internal` so they get compiled into contracts using them.
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library MessageSigning {
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function recoverAddressFromSignedMessage(bytes signature, bytes message) internal pure returns (address) {
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require(signature.length == 65);
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bytes32 r;
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bytes32 s;
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@ -48,23 +64,100 @@ library Signer {
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s := mload(add(signature, 0x40))
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v := mload(add(signature, 0x60))
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}
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return ecrecover(hash(message), uint8(v), r, s);
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return ecrecover(hashMessage(message), uint8(v), r, s);
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}
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function hash (bytes message) internal pure returns (bytes32) {
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function hashMessage(bytes message) internal pure returns (bytes32) {
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bytes memory prefix = "\x19Ethereum Signed Message:\n";
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return keccak256(prefix, Utils.toString(message.length), message);
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return keccak256(prefix, Helpers.uintToString(message.length), message);
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}
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}
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contract HomeBridge {
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using Authorities for address[];
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/// Library used only to test MessageSigning library via rpc calls
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library MessageSigningTest {
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function recoverAddressFromSignedMessage(bytes signature, bytes message) public pure returns (address) {
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return MessageSigning.recoverAddressFromSignedMessage(signature, message);
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}
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}
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library Message {
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// layout of message :: bytes:
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// offset 0: 32 bytes :: uint (little endian) - message length
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// offset 32: 20 bytes :: address - recipient address
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// offset 52: 32 bytes :: uint (little endian) - value
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// offset 84: 32 bytes :: bytes32 - transaction hash
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// bytes 1 to 32 are 0 because message length is stored as little endian.
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// mload always reads 32 bytes.
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// so we can and have to start reading recipient at offset 20 instead of 32.
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// if we were to read at 32 the address would contain part of value and be corrupted.
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// when reading from offset 20 mload will read 12 zero bytes followed
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// by the 20 recipient address bytes and correctly convert it into an address.
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// this saves some storage/gas over the alternative solution
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// which is padding address to 32 bytes and reading recipient at offset 32.
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// for more details see discussion in:
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// https://github.com/paritytech/parity-bridge/issues/61
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function getRecipient(bytes message) internal pure returns (address) {
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address recipient;
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// solium-disable-next-line security/no-inline-assembly
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assembly {
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recipient := mload(add(message, 20))
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}
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return recipient;
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}
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function getValue(bytes message) internal pure returns (uint) {
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uint value;
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// solium-disable-next-line security/no-inline-assembly
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assembly {
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value := mload(add(message, 52))
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}
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return value;
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}
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function getTransactionHash(bytes message) internal pure returns (bytes32) {
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bytes32 hash;
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// solium-disable-next-line security/no-inline-assembly
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assembly {
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hash := mload(add(message, 84))
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}
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return hash;
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}
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}
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/// Library used only to test Message library via rpc calls
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library MessageTest {
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function getRecipient(bytes message) public pure returns (address) {
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return Message.getRecipient(message);
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}
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function getValue(bytes message) public pure returns (uint) {
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return Message.getValue(message);
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}
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function getTransactionHash(bytes message) public pure returns (bytes32) {
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return Message.getTransactionHash(message);
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}
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}
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contract HomeBridge {
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/// Number of authorities signatures required to withdraw the money.
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///
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/// Must be lesser than number of authorities.
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uint public requiredSignatures;
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/// The gas cost of calling `HomeBridge.withdraw`.
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///
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/// Is subtracted from `value` on withdraw.
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/// recipient pays the relaying authority for withdraw.
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/// this shuts down attacks that exhaust authorities funds on home chain.
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uint public estimatedGasCostOfWithdraw;
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/// Contract authorities.
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address[] public authorities;
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@ -78,27 +171,33 @@ contract HomeBridge {
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event Withdraw (address recipient, uint value);
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/// Multisig authority validation
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modifier allAuthorities (uint8[] v, bytes32[] r, bytes32[] s, bytes message) {
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var hash = Signer.hash(message);
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modifier allAuthorities(uint8[] v, bytes32[] r, bytes32[] s, bytes message) {
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var hash = MessageSigning.hashMessage(message);
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var used = new address[](requiredSignatures);
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require(requiredSignatures <= v.length);
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for (uint i = 0; i < requiredSignatures; i++) {
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var a = ecrecover(hash, v[i], r[i], s[i]);
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require(authorities.contains(a));
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require(!used.contains(a));
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require(Helpers.addressArrayContains(authorities, a));
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require(!Helpers.addressArrayContains(used, a));
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used[i] = a;
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}
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_;
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}
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/// Constructor.
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function HomeBridge (uint n, address[] a) public {
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require(n != 0);
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require(n <= a.length);
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requiredSignatures = n;
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authorities = a;
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function HomeBridge(
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uint requiredSignaturesParam,
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address[] authoritiesParam,
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uint estimatedGasCostOfWithdrawParam
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) public
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{
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require(requiredSignaturesParam != 0);
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require(requiredSignaturesParam <= authoritiesParam.length);
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requiredSignatures = requiredSignaturesParam;
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authorities = authoritiesParam;
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estimatedGasCostOfWithdraw = estimatedGasCostOfWithdrawParam;
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}
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/// Should be used to deposit money.
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@ -106,6 +205,18 @@ contract HomeBridge {
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Deposit(msg.sender, msg.value);
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}
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/// to be called by authorities to check
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/// whether they withdraw message should be relayed or whether it
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/// is too low to cover the cost of calling withdraw and can be ignored
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function isMessageValueSufficientToCoverRelay(bytes message) public view returns (bool) {
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return Message.getValue(message) > getWithdrawRelayCost();
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}
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/// an upper bound to the cost of relaying a withdraw by calling HomeBridge.withdraw
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function getWithdrawRelayCost() public view returns (uint) {
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return estimatedGasCostOfWithdraw * tx.gasprice;
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}
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/// Used to withdraw money from the contract.
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///
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/// message contains:
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@ -113,44 +224,36 @@ contract HomeBridge {
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/// withdrawal value (uint)
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/// foreign transaction hash (bytes32) // to avoid transaction duplication
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///
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/// NOTE that anyone can call withdraw provided they have the
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/// message and required signatures!
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function withdraw (uint8[] v, bytes32[] r, bytes32[] s, bytes message) public allAuthorities(v, r, s, message) {
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/// NOTE that anyone can call withdraw provided they have the message and required signatures!
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function withdraw(uint8[] v, bytes32[] r, bytes32[] s, bytes message) public allAuthorities(v, r, s, message) {
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require(message.length == 84);
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address recipient;
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uint value;
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bytes32 hash;
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// solium-disable-next-line security/no-inline-assembly
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assembly {
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// layout of message :: bytes:
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// offset 0: 32 bytes :: uint (little endian) - message length
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// offset 32: 20 bytes :: address - recipient address
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// offset 52: 32 bytes :: uint (little endian) - value
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// offset 84: 32 bytes :: bytes32 - transaction hash
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address recipient = Message.getRecipient(message);
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uint value = Message.getValue(message);
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bytes32 hash = Message.getTransactionHash(message);
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// we require above that message length == 84.
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// bytes 1 to 32 are 0 because message length is stored as little endian.
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// mload always reads 32 bytes.
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// so we can and have to start reading recipient at offset 20 instead of 32.
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// if we were to read at 32 the address would contain part of value and be corrupted.
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// when reading from offset 20 mload will read 12 zero bytes followed
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// by the 20 recipient address bytes and correctly convert it into an address.
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// this saves some storage/gas over the alternative solution
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// which is padding address to 32 bytes and reading recipient at offset 32.
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// for more details see discussion in:
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// https://github.com/paritytech/parity-bridge/issues/61
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recipient := mload(add(message, 20))
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value := mload(add(message, 52))
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hash := mload(add(message, 84))
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}
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// Duplicated withdraw
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// The following two statements guard against reentry into this function.
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// Duplicated withdraw or reentry.
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require(!withdraws[hash]);
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// Order of operations below is critical to avoid TheDAO-like bug
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// Order of operations below is critical to avoid TheDAO-like re-entry bug
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withdraws[hash] = true;
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recipient.transfer(value);
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Withdraw(recipient, value);
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// this fails if `value` is not even enough to cover the relay cost.
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// Authorities simply IGNORE withdraws where `value` can’t relay cost.
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// Think of it as `value` getting burned entirely on the relay with no value left to pay out the recipient.
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require(isMessageValueSufficientToCoverRelay(message));
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uint estimatedWeiCostOfWithdraw = getWithdrawRelayCost();
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// charge recipient for relay cost
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uint valueRemainingAfterSubtractingCost = value - estimatedWeiCostOfWithdraw;
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// pay out recipient
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recipient.transfer(valueRemainingAfterSubtractingCost);
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// refund relay cost to relaying authority
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msg.sender.transfer(estimatedWeiCostOfWithdraw);
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Withdraw(recipient, valueRemainingAfterSubtractingCost);
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}
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}
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@ -161,8 +264,6 @@ contract ERC20 {
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}
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contract ForeignBridge {
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using Authorities for address[];
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struct SignaturesCollection {
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/// Signed message.
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bytes message;
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@ -180,41 +281,51 @@ contract ForeignBridge {
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/// Contract authorities.
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address[] public authorities;
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/// Ether balances
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mapping (address => uint) public balances;
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/// Pending deposits and authorities who confirmed them
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mapping (bytes32 => address[]) deposits;
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/// List of authorities confirmed to set up ERC-20 token address
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mapping (address => address[]) public token_address;
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/// Token to work with
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ERC20 public erc20token;
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/// Event created when new token address is set up.
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event TokenAddress(address token);
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/// Pending signatures and authorities who confirmed them
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mapping (bytes32 => SignaturesCollection) signatures;
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/// List of authorities confirmed to set up ERC-20 token address
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mapping (address => address[]) tokenAddressAprrovals;
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/// Token to work with
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ERC20 public erc20token;
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/// Event created on money deposit.
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event Deposit(address recipient, uint value);
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/// Event created on money withdraw.
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event Withdraw(address recipient, uint value);
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/// Event created on money transfer
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event Transfer(address from, address to, uint value);
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/// Collected signatures which should be relayed to home chain.
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event CollectedSignatures(address authority, bytes32 messageHash);
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/// Event created when new token address is set up.
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event TokenAddress(address token);
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/// Constructor.
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function ForeignBridge(uint n, address[] a) public {
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require(n != 0);
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require(n <= a.length);
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requiredSignatures = n;
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authorities = a;
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function ForeignBridge(
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uint requiredSignaturesParam,
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address[] authoritiesParam
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) public
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{
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require(requiredSignaturesParam != 0);
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require(requiredSignaturesParam <= authoritiesParam.length);
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requiredSignatures = requiredSignaturesParam;
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authorities = authoritiesParam;
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}
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/// Multisig authority validation
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modifier onlyAuthority () {
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require(authorities.contains(msg.sender));
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modifier onlyAuthority() {
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require(Helpers.addressArrayContains(authorities, msg.sender));
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_;
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}
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@ -223,27 +334,32 @@ contract ForeignBridge {
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/// token address (address)
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function setTokenAddress (ERC20 token) public onlyAuthority() {
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// Protect duplicated request
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require(!token_address[token].contains(msg.sender));
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require(!Helpers.addressArrayContains(tokenAddressAprrovals[token], msg.sender));
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token_address[token].push(msg.sender);
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tokenAddressAprrovals[token].push(msg.sender);
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// TODO: this may cause troubles if requriedSignatures len is changed
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if (token_address[token].length == requiredSignatures) {
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if (tokenAddressAprrovals[token].length == requiredSignatures) {
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erc20token = ERC20(token);
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TokenAddress(token);
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}
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}
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/// Used to deposit money to the contract.
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/// Used to transfer tokens to the `recipient`.
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/// The bridge contract must own enough tokens to release them for
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/// recipients. Tokens must be transfered to the bridge contract BEFORE
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/// the first deposit will be performed.
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///
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/// deposit recipient (bytes20)
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/// deposit value (uint)
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/// mainnet transaction hash (bytes32) // to avoid transaction duplication
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function deposit (address recipient, uint value, bytes32 transactionHash) public onlyAuthority() {
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function deposit(address recipient, uint value, bytes32 transactionHash) public onlyAuthority() {
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require(erc20token != address(0x0));
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// Protection from misbehaing authority
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var hash = keccak256(recipient, value, transactionHash);
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bytes32 hash = keccak256(recipient, value, transactionHash);
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// Duplicated deposits
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require(!deposits[hash].contains(msg.sender));
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require(!Helpers.addressArrayContains(deposits[hash], msg.sender));
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deposits[hash].push(msg.sender);
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// TODO: this may cause troubles if requriedSignatures len is changed
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@ -253,15 +369,30 @@ contract ForeignBridge {
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}
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}
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/// To swap token to money the account must allow this explicitly
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/// in the token contract by calling approveAndCall with address
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/// Used to transfer `value` of tokens from `_from`s balance on local
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/// (`foreign`) chain to the same address (`_from`) on `home` chain.
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/// Transfer of tokens within local (`foreign`) chain performed by usual
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/// way through transfer method of the token contract.
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/// In order to swap tokens to coins the owner (`_from`) must allow this
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/// explicitly in the token contract by calling approveAndCall with address
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/// of the bridge account.
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function receiveApproval(address _from, uint256 _value, address _tokenContract, bytes _msg) external returns(bool) {
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require(msg.sender == address(erc20token));
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require(erc20token.allowance(_from, this) >= _value);
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/// The method locks tokens and emits a `Withdraw` event which will be
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/// picked up by the bridge authorities.
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/// Bridge authorities will then sign off (by calling `submitSignature`) on
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/// a message containing `value`, the recipient (`_from`) and the `hash` of
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/// the transaction on `foreign` containing the `Withdraw` event.
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/// Once `requiredSignatures` are collected a `CollectedSignatures` event
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/// will be emitted.
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/// An authority will pick up `CollectedSignatures` an call
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/// `HomeBridge.withdraw` which transfers `value - relayCost` to the
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/// recipient completing the transfer.
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function receiveApproval(address _from, uint256 _value, ERC20 _tokenContract, bytes _msg) external returns(bool) {
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require(erc20token != address(0x0));
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require(msg.sender == address(erc20token));
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require(erc20token.allowance(_from, this) >= _value);
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erc20token.transferFrom(_from, this, _value);
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Withdraw(_from, _value);
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|
||||
return true;
|
||||
}
|
||||
|
||||
|
|
@ -273,16 +404,16 @@ contract ForeignBridge {
|
|||
/// withdrawal recipient (bytes20)
|
||||
/// withdrawal value (uint)
|
||||
/// foreign transaction hash (bytes32) // to avoid transaction duplication
|
||||
function submitSignature (bytes signature, bytes message) public onlyAuthority() {
|
||||
function submitSignature(bytes signature, bytes message) public onlyAuthority() {
|
||||
// Validate submited signatures
|
||||
require(Signer.signer(signature, message) == msg.sender);
|
||||
require(MessageSigning.recoverAddressFromSignedMessage(signature, message) == msg.sender);
|
||||
|
||||
// Valid withdraw message must have 84 bytes
|
||||
require(message.length == 84);
|
||||
var hash = keccak256(message);
|
||||
bytes32 hash = keccak256(message);
|
||||
|
||||
// Duplicated signatures
|
||||
require(!signatures[hash].signed.contains(msg.sender));
|
||||
require(!Helpers.addressArrayContains(signatures[hash].signed, msg.sender));
|
||||
signatures[hash].message = message;
|
||||
signatures[hash].signed.push(msg.sender);
|
||||
signatures[hash].signatures.push(signature);
|
||||
|
|
@ -294,12 +425,12 @@ contract ForeignBridge {
|
|||
}
|
||||
|
||||
/// Get signature
|
||||
function signature (bytes32 hash, uint index) public view returns (bytes) {
|
||||
function signature(bytes32 hash, uint index) public view returns (bytes) {
|
||||
return signatures[hash].signatures[index];
|
||||
}
|
||||
|
||||
/// Get message
|
||||
function message (bytes32 hash) public view returns (bytes) {
|
||||
function message(bytes32 hash) public view returns (bytes) {
|
||||
return signatures[hash].message;
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,3 +1,5 @@
|
|||
estimated_gas_cost_of_withdraw = 0
|
||||
|
||||
[home]
|
||||
account = "0x842eb2142c5aa1260954f07aae39ddee1640c3a7"
|
||||
ipc = "/home/koal/parity/PoA_home/jsonrpc.ipc"
|
||||
|
|
@ -27,6 +29,6 @@ required_signatures = 1
|
|||
[transactions]
|
||||
home_deploy = { gas = 3000000, gas_price = 18000000000 }
|
||||
foreign_deploy = { gas = 3000000, gas_price = 18000000000 }
|
||||
deposit_relay = { gas = 120000, gas_price = 18000000000 }
|
||||
withdraw_confirm = { gas = 120000, gas_price = 18000000000 }
|
||||
withdraw_relay = { gas = 300000, gas_price = 18000000000 }
|
||||
deposit_relay = { gas = 1200000, gas_price = 18000000000 }
|
||||
withdraw_confirm = { gas = 3000000, gas_price = 18000000000 }
|
||||
withdraw_relay = { gas = 3000000, gas_price = 18000000000 }
|
||||
|
|
|
|||
Loading…
Reference in New Issue