110 lines
3.7 KiB
Solidity
110 lines
3.7 KiB
Solidity
// contracts/Messages.sol
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// SPDX-License-Identifier: Apache 2
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pragma solidity ^0.8.0;
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pragma experimental ABIEncoderV2;
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import "./Getters.sol";
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import "./Structs.sol";
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import "./libraries/external/BytesLib.sol";
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contract Messages is Getters {
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using BytesLib for bytes;
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function parseAndVerifyVM(bytes calldata encodedVM) public view returns (Structs.VM memory vm, bool valid, string memory reason) {
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vm = parseVM(encodedVM);
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(valid, reason) = verifyVM(vm);
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}
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function verifyVM(Structs.VM memory vm) public view returns (bool valid, string memory reason) {
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Structs.GuardianSet memory guardianSet = getGuardianSet(vm.guardianSetIndex);
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if(guardianSet.keys.length == 0){
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return (false, "invalid guardian set");
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}
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if(vm.guardianSetIndex != getCurrentGuardianSetIndex() && guardianSet.expirationTime < block.timestamp){
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return (false, "guardian set has expired");
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}
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// We're using a fixed point number transformation with 1 decimal to deal with rounding.
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if(((guardianSet.keys.length * 10 / 3) * 2) / 10 + 1 > vm.signatures.length){
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return (false, "no quorum");
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}
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// Verify signatures
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(bool signaturesValid, string memory invalidReason) = verifySignatures(vm.hash, vm.signatures, guardianSet);
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if(!signaturesValid){
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return (false, invalidReason);
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}
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return (true, "");
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}
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function verifySignatures(bytes32 hash, Structs.Signature[] memory signatures, Structs.GuardianSet memory guardianSet) public pure returns (bool valid, string memory reason) {
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uint8 lastIndex = 0;
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for (uint i = 0; i < signatures.length; i++) {
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Structs.Signature memory sig = signatures[i];
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require(i == 0 || sig.guardianIndex > lastIndex, "signature indices must be ascending");
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lastIndex = sig.guardianIndex;
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if(ecrecover(hash, sig.v, sig.r, sig.s) != guardianSet.keys[sig.guardianIndex]){
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return (false, "VM signature invalid");
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}
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}
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return (true, "");
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}
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function parseVM(bytes memory encodedVM) public pure virtual returns (Structs.VM memory vm) {
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uint index = 0;
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vm.version = encodedVM.toUint8(index);
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index += 1;
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require(vm.version == 1, "VM version incompatible");
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vm.guardianSetIndex = encodedVM.toUint32(index);
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index += 4;
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// Parse Signatures
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uint256 signersLen = encodedVM.toUint8(index);
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index += 1;
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vm.signatures = new Structs.Signature[](signersLen);
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for (uint i = 0; i < signersLen; i++) {
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vm.signatures[i].guardianIndex = encodedVM.toUint8(index);
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index += 1;
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vm.signatures[i].r = encodedVM.toBytes32(index);
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index += 32;
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vm.signatures[i].s = encodedVM.toBytes32(index);
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index += 32;
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vm.signatures[i].v = encodedVM.toUint8(index) + 27;
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index += 1;
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}
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// Hash the body
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bytes memory body = encodedVM.slice(index, encodedVM.length - index);
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vm.hash = keccak256(abi.encodePacked(keccak256(body)));
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// Parse the body
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vm.timestamp = encodedVM.toUint32(index);
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index += 4;
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vm.nonce = encodedVM.toUint32(index);
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index += 4;
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vm.emitterChainId = encodedVM.toUint16(index);
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index += 2;
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vm.emitterAddress = encodedVM.toBytes32(index);
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index += 32;
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vm.sequence = encodedVM.toUint64(index);
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index += 8;
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vm.consistencyLevel = encodedVM.toUint8(index);
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index += 1;
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vm.payload = encodedVM.slice(index, encodedVM.length - index);
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}
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}
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