335 lines
15 KiB
Ruby
335 lines
15 KiB
Ruby
//////////////////////////////////////////////////////////////////////////////
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///////////////////// Governor.sol base definitions //////////////////////////
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//////////////////////////////////////////////////////////////////////////////
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using ERC20VotesHarness as erc20votes
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methods {
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proposalSnapshot(uint256) returns uint256 envfree // matches proposalVoteStart
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proposalDeadline(uint256) returns uint256 envfree // matches proposalVoteEnd
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hashProposal(address[],uint256[],bytes[],bytes32) returns uint256 envfree
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isExecuted(uint256) returns bool envfree
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isCanceled(uint256) returns bool envfree
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execute(address[], uint256[], bytes[], bytes32) returns uint256
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hasVoted(uint256, address) returns bool
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castVote(uint256, uint8) returns uint256
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updateQuorumNumerator(uint256)
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queue(address[], uint256[], bytes[], bytes32) returns uint256
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// internal functions made public in harness:
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_quorumReached(uint256) returns bool
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_voteSucceeded(uint256) returns bool envfree
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// function summarization
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proposalThreshold() returns uint256 envfree
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getVotes(address, uint256) returns uint256 => DISPATCHER(true)
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getPastTotalSupply(uint256 t) returns uint256 => PER_CALLEE_CONSTANT
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getPastVotes(address a, uint256 t) returns uint256 => PER_CALLEE_CONSTANT
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//scheduleBatch(address[],uint256[],bytes[],bytes32,bytes32,uint256) => DISPATCHER(true)
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//executeBatch(address[], uint256[], bytes[], bytes32, bytes32) => DISPATCHER(true)
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}
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//////////////////////////////////////////////////////////////////////////////
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//////////////////////////////// Definitions /////////////////////////////////
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//////////////////////////////////////////////////////////////////////////////
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// proposal was created - relation proved in noStartBeforeCreation
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definition proposalCreated(uint256 pId) returns bool = proposalSnapshot(pId) > 0;
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//////////////////////////////////////////////////////////////////////////////
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///////////////////////////// Helper Functions ///////////////////////////////
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//////////////////////////////////////////////////////////////////////////////
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function helperFunctionsWithRevert(uint256 proposalId, method f, env e) {
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address[] targets; uint256[] values; bytes[] calldatas; string reason; bytes32 descriptionHash;
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uint8 support; uint8 v; bytes32 r; bytes32 s;
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if (f.selector == propose(address[], uint256[], bytes[], string).selector) {
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uint256 result = propose@withrevert(e, targets, values, calldatas, reason);
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require(result == proposalId);
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} else if (f.selector == execute(address[], uint256[], bytes[], bytes32).selector) {
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uint256 result = execute@withrevert(e, targets, values, calldatas, descriptionHash);
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require(result == proposalId);
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} else if (f.selector == castVote(uint256, uint8).selector) {
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castVote@withrevert(e, proposalId, support);
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} else if (f.selector == castVoteWithReason(uint256, uint8, string).selector) {
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castVoteWithReason@withrevert(e, proposalId, support, reason);
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} else if (f.selector == castVoteBySig(uint256, uint8,uint8, bytes32, bytes32).selector) {
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castVoteBySig@withrevert(e, proposalId, support, v, r, s);
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} else if (f.selector == queue(address[], uint256[], bytes[], bytes32).selector) {
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queue@withrevert(e, targets, values, calldatas, descriptionHash);
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} else {
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calldataarg args;
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f@withrevert(e, args);
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}
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}
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/*
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////// State Diagram //////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// //
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// castVote(s)() //
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// ------------- propose() ---------------------- time pass --------------- time passes ----------- //
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// | No Proposal | --------> | Before Start (Delay) | --------> | Voting Period | ----------------------> | execute() | //
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// ------------- ---------------------- --------------- -> Executed/Canceled ----------- //
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// ------------------------------------------------------------|---------------|-------------------------|--------------> //
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// t start end timelock //
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// //
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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*/
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///////////////////////////////////////////////////////////////////////////////////////
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///////////////////////////////// Global Valid States /////////////////////////////////
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///////////////////////////////////////////////////////////////////////////////////////
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/*
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* Start and end date are either initialized (non zero) or uninitialized (zero) simultaneously
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* This invariant assumes that the block number cannot be 0 at any stage of the contract cycle
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* This is very safe assumption as usually the 0 block is genesis block which is uploaded with data
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* by the developers and will not be valid to raise proposals (at the current way that block chain is functioning)
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*/
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// To use env with general preserved block disable type checking [--disableLocalTypeChecking]
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invariant startAndEndDatesNonZero(uint256 pId)
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proposalSnapshot(pId) != 0 <=> proposalDeadline(pId) != 0
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{ preserved with (env e){
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require e.block.number > 0;
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}}
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/*
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* If a proposal is canceled it must have a start and an end date
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*/
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// To use env with general preserved block disable type checking [--disableLocalTypeChecking]
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invariant canceledImplyStartAndEndDateNonZero(uint pId)
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isCanceled(pId) => proposalSnapshot(pId) != 0
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{preserved with (env e){
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require e.block.number > 0;
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}}
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/*
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* If a proposal is executed it must have a start and an end date
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*/
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// To use env with general preserved block disable type checking [--disableLocalTypeChecking]
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invariant executedImplyStartAndEndDateNonZero(uint pId)
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isExecuted(pId) => proposalSnapshot(pId) != 0
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{ preserved with (env e){
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requireInvariant startAndEndDatesNonZero(pId);
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require e.block.number > 0;
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}}
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/*
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* A proposal starting block number must be less or equal than the proposal end date
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*/
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invariant voteStartBeforeVoteEnd(uint256 pId)
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// from < to <= because snapshot and deadline can be the same block number if delays are set to 0
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// This is possible before the integration of GovernorSettings.sol to the system.
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// After integration of GovernorSettings.sol the invariant expression should be changed from <= to <
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(proposalSnapshot(pId) > 0 => proposalSnapshot(pId) <= proposalDeadline(pId))
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// (proposalSnapshot(pId) > 0 => proposalSnapshot(pId) <= proposalDeadline(pId))
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{ preserved {
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requireInvariant startAndEndDatesNonZero(pId);
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}}
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/*
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* A proposal cannot be both executed and canceled simultaneously.
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*/
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invariant noBothExecutedAndCanceled(uint256 pId)
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!isExecuted(pId) || !isCanceled(pId)
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/*
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* A proposal could be executed only if quorum was reached and vote succeeded
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*/
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rule executionOnlyIfQuoromReachedAndVoteSucceeded(uint256 pId, env e, method f){
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bool isExecutedBefore = isExecuted(pId);
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bool quorumReachedBefore = _quorumReached(e, pId);
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bool voteSucceededBefore = _voteSucceeded(pId);
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calldataarg args;
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f(e, args);
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bool isExecutedAfter = isExecuted(pId);
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assert (!isExecutedBefore && isExecutedAfter) => (quorumReachedBefore && voteSucceededBefore), "quorum was changed";
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}
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///////////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////// In-State Rules /////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////////////////
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//==========================================
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//------------- Voting Period --------------
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//==========================================
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/*
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* A user cannot vote twice
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*/
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// Checked for castVote only. all 3 castVote functions call _castVote, so the completeness of the verification is counted on
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// the fact that the 3 functions themselves makes no changes, but rather call an internal function to execute.
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// That means that we do not check those 3 functions directly, however for castVote & castVoteWithReason it is quite trivial
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// to understand why this is ok. For castVoteBySig we basically assume that the signature referendum is correct without checking it.
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// We could check each function separately and pass the rule, but that would have uglyfied the code with no concrete
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// benefit, as it is evident that nothing is happening in the first 2 functions (calling a view function), and we do not desire to check the signature verification.
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rule doubleVoting(uint256 pId, uint8 sup, method f) {
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env e;
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address user = e.msg.sender;
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bool votedCheck = hasVoted(e, pId, user);
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castVote@withrevert(e, pId, sup);
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assert votedCheck => lastReverted, "double voting accured";
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}
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///////////////////////////////////////////////////////////////////////////////////////
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//////////////////////////// State Transitions Rules //////////////////////////////////
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///////////////////////////////////////////////////////////////////////////////////////
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//===========================================
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//-------- Propose() --> End of Time --------
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//===========================================
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/*
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* Once a proposal is created, voteStart and voteEnd are immutable
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*/
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rule immutableFieldsAfterProposalCreation(uint256 pId, method f) {
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uint256 _voteStart = proposalSnapshot(pId);
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uint256 _voteEnd = proposalDeadline(pId);
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require proposalCreated(pId); // startDate > 0
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env e; calldataarg arg;
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f(e, arg);
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uint256 voteStart_ = proposalSnapshot(pId);
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uint256 voteEnd_ = proposalDeadline(pId);
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assert _voteStart == voteStart_, "Start date was changed";
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assert _voteEnd == voteEnd_, "End date was changed";
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}
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/*
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* Voting cannot start at a block number prior to proposal’s creation block number
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*/
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rule noStartBeforeCreation(uint256 pId) {
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uint256 previousStart = proposalSnapshot(pId);
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// This line makes sure that we see only cases where start date is changed from 0, i.e. creation of proposal
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// We proved in immutableFieldsAfterProposalCreation that once dates set for proposal, it cannot be changed
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require !proposalCreated(pId); // previousStart == 0;
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env e; calldataarg args;
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propose(e, args);
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uint256 newStart = proposalSnapshot(pId);
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// if created, start is after current block number (creation block)
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assert(newStart != previousStart => newStart >= e.block.number);
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}
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//============================================
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//--- End of Voting Period --> End of Time ---
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//============================================
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/*
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* A proposal can neither be executed nor canceled before it ends
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*/
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// By induction it cannot be executed nor canceled before it starts, due to voteStartBeforeVoteEnd
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rule noExecuteOrCancelBeforeDeadline(uint256 pId, method f){
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require !isExecuted(pId) && !isCanceled(pId);
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env e; calldataarg args;
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f(e, args);
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assert e.block.number < proposalDeadline(pId) => (!isExecuted(pId) && !isCanceled(pId)), "executed/cancelled before deadline";
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}
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////////////////////////////////////////////////////////////////////////////////
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////////////////////// Integrity Of Functions (Unit Tests) /////////////////////
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////// High Level Rules ////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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///////////////////////////// Not Categorized Yet //////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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/*
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* All proposal specific (non-view) functions should revert if proposal is executed
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*/
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// In this rule we show that if a function is executed, i.e. execute() was called on the proposal ID,
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// non of the proposal specific functions can make changes again. In executedOnlyAfterExecuteFunc
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// we connected the executed attribute to the execute() function, showing that only execute() can
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// change it, and that it will always change it.
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rule allFunctionsRevertIfExecuted(method f) filtered { f ->
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!f.isView && !f.isFallback
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&& f.selector != updateTimelock(address).selector
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&& f.selector != updateQuorumNumerator(uint256).selector
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&& f.selector != queue(address[],uint256[],bytes[],bytes32).selector
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&& f.selector != relay(address,uint256,bytes).selector
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&& f.selector != 0xb9a61961 // __acceptAdmin()
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} {
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env e; calldataarg args;
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uint256 pId;
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require(isExecuted(pId));
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requireInvariant noBothExecutedAndCanceled(pId);
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requireInvariant executedImplyStartAndEndDateNonZero(pId);
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helperFunctionsWithRevert(pId, f, e);
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assert(lastReverted, "Function was not reverted");
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}
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/*
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* All proposal specific (non-view) functions should revert if proposal is canceled
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*/
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rule allFunctionsRevertIfCanceled(method f) filtered {
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f -> !f.isView && !f.isFallback
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&& f.selector != updateTimelock(address).selector
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&& f.selector != updateQuorumNumerator(uint256).selector
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&& f.selector != queue(address[],uint256[],bytes[],bytes32).selector
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&& f.selector != relay(address,uint256,bytes).selector
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&& f.selector != 0xb9a61961 // __acceptAdmin()
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} {
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env e; calldataarg args;
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uint256 pId;
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require(isCanceled(pId));
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requireInvariant noBothExecutedAndCanceled(pId);
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requireInvariant canceledImplyStartAndEndDateNonZero(pId);
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helperFunctionsWithRevert(pId, f, e);
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assert(lastReverted, "Function was not reverted");
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}
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/*
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* Proposal can be switched to executed only via execute() function
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*/
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rule executedOnlyAfterExecuteFunc(address[] targets, uint256[] values, bytes[] calldatas, bytes32 descriptionHash, method f) {
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env e; calldataarg args;
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uint256 pId;
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bool executedBefore = isExecuted(pId);
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require(!executedBefore);
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helperFunctionsWithRevert(pId, f, e);
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bool executedAfter = isExecuted(pId);
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assert(executedAfter != executedBefore => f.selector == execute(address[], uint256[], bytes[], bytes32).selector, "isExecuted only changes in the execute method");
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}
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