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openzeppelin-contracts/certora/specs/GovernorBase.spec

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//////////////////////////////////////////////////////////////////////////////
///////////////////// Governor.sol base definitions //////////////////////////
//////////////////////////////////////////////////////////////////////////////
using ERC20VotesHarness as erc20votes
methods {
proposalSnapshot(uint256) returns uint256 envfree // matches proposalVoteStart
proposalDeadline(uint256) returns uint256 envfree // matches proposalVoteEnd
hashProposal(address[],uint256[],bytes[],bytes32) returns uint256 envfree
isExecuted(uint256) returns bool envfree
isCanceled(uint256) returns bool envfree
execute(address[], uint256[], bytes[], bytes32) returns uint256
hasVoted(uint256, address) returns bool
castVote(uint256, uint8) returns uint256
updateQuorumNumerator(uint256)
// internal functions made public in harness:
_quorumReached(uint256) returns bool
_voteSucceeded(uint256) returns bool envfree
_pId_Harness() returns uint256 envfree;
// function summarization
hashProposal(address[], uint256[], bytes[], bytes32) => CONSTANT
proposalThreshold() returns uint256 envfree
getVotes(address, uint256) returns uint256 => DISPATCHER(true)
//getVotes(address, uint256) => DISPATCHER(true)
erc20votes.getPastTotalSupply(uint256) returns uint256
//getPastTotalSupply(uint256) => DISPATCHER(true)
erc20votes.getPastVotes(address, uint256) returns uint256
}
//////////////////////////////////////////////////////////////////////////////
////////////////////////////////// Ghosts ////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
// ghost uniqueHashGhost(bytes32) returns uint256;
//////////////////////////////////////////////////////////////////////////////
///////////////////////////// Helper Functions ///////////////////////////////
//////////////////////////////////////////////////////////////////////////////
function callFunctionWithProposal(uint256 proposalId, method f) {
address[] targets; uint256[] values; bytes[] calldatas; bytes32 descriptionHash;
uint8 support; uint8 v; bytes32 r; bytes32 s;
env e;
if (f.selector == callPropose(address[], uint256[], bytes[]).selector) {
uint256 result = callPropose@withrevert(e, targets, values, calldatas);
require(proposalId == result);
} else if (f.selector == execute(address[], uint256[], bytes[], bytes32).selector) {
uint256 result = execute@withrevert(e, targets, values, calldatas, descriptionHash);
require(result == proposalId);
} else if (f.selector == castVote(uint256, uint8).selector) {
castVote@withrevert(e, proposalId, support);
} else if (f.selector == 0x7b3c71d3) {
calldataarg args;
require(_pId_Harness() == proposalId);
f@withrevert(e, args);
} else if (f.selector == castVoteBySig(uint256, uint8,uint8, bytes32, bytes32).selector) {
castVoteBySig@withrevert(e, proposalId, support, v, r, s);
} else {
calldataarg args;
f@withrevert(e, args);
}
}
/*
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////// State Diagram //////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// //
// castVote(s)() //
// ------------- propose() ---------------------- time pass --------------- time passes ----------- //
// | No Proposal | --------> | Before Start (Delay) | --------> | Voting Period | ----------------------> | execute() | //
// ------------- ---------------------- --------------- -> Executed/Canceled ----------- //
// ------------------------------------------------------------|---------------|-------------------------|--------------> //
// t start end timelock //
// //
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
*/
///////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////// Global Valid States /////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////
/*
* If any of the properties are non zero, the rest has to be non zero
*/
invariant proposalInitiated(uint256 pId)
(proposalSnapshot(pId) != 0 <=> proposalDeadline(pId) != 0) &&
(isCanceled(pId) => proposalSnapshot(pId) != 0) &&
(isExecuted(pId) => proposalSnapshot(pId) != 0)
/*{ preserved with (env e){
require e.block.number > 0;
}}*/
/*
* A proposal cannot end unless it started.
*/
invariant voteStartBeforeVoteEnd(uint256 pId)
(proposalSnapshot(pId) > 0 => proposalSnapshot(pId) <= proposalDeadline(pId)) // from < to <= because snapshot and deadline can be the same block number if delays are set to 0
&& (proposalSnapshot(pId) == 0 => proposalDeadline(pId) == 0)
/*
* A proposal cannot be both executed and canceled.
*/
invariant noBothExecutedAndCanceled(uint256 pId)
!isExecuted(pId) || !isCanceled(pId)
/**
* A proposal could be executed only if quorum was reached and vote succeeded
*/
//invariant executionOnlyIfQuoromReachedAndVoteSucceeded(uint256 pId, env e)
// isExecuted(pId) => _quorumReached(e, pId) && _voteSucceeded(pId)
rule executionOnlyIfQuoromReachedAndVoteSucceeded(uint256 pId, env e, method f){
bool isExecutedBefore = isExecuted(pId);
calldataarg args;
f(e, args);
bool isExecutedAfter = isExecuted(pId);
assert isExecutedBefore != isExecutedAfter => _quorumReached(e, pId) && _voteSucceeded(pId), "quorum was changed";
}
///////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////// In-State Rules /////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////
//==========================================
//------------- Voting Period --------------
//==========================================
/*
* A user cannot vote twice
*/
rule doubleVoting(uint256 pId, uint8 sup) {
env e;
address user = e.msg.sender;
bool votedCheck = hasVoted(e, pId, user);
castVote@withrevert(e, pId, sup);
bool reverted = lastReverted;
assert votedCheck => reverted, "double voting accured";
}
///////////////////////////////////////////////////////////////////////////////////////
//////////////////////////// State Transitions Rules //////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////
//===========================================
//-------- Propose() --> End of Time --------
//===========================================
/*
* The voting must start not before the proposal’s creation time
*/
rule noStartBeforeCreation(uint256 pId) {
uint256 previousStart = proposalSnapshot(pId);
require previousStart == 0;
env e;
calldataarg arg;
propose(e, arg);
uint newStart = proposalSnapshot(pId);
// if created, start is after current block number (creation block)
assert(newStart != previousStart => newStart >= e.block.number);
}
/*
* Once a proposal is created, voteStart and voteEnd are immutable
*/
rule immutableFieldsAfterProposalCreation(uint256 pId, method f) {
uint _voteStart = proposalSnapshot(pId);
uint _voteEnd = proposalDeadline(pId);
require _voteStart > 0; // proposal was created - relation proved in noStartBeforeCreation
env e;
calldataarg arg;
f(e, arg);
uint voteStart_ = proposalSnapshot(pId);
uint voteEnd_ = proposalDeadline(pId);
assert _voteStart == voteStart_;
assert _voteEnd == voteEnd_;
}
/*
* A proposal cannot be neither executed nor canceled before it starts
*/
rule noExecuteOrCancelBeforeStarting(uint256 pId, method f){
env e;
require !isExecuted(pId) && !isCanceled(pId);
calldataarg arg;
f(e, arg);
assert e.block.number < proposalSnapshot(pId) => (!isExecuted(pId) && !isCanceled(pId)), "executed/cancelled before start";
}
//============================================
//--- End of Voting Period --> End of Time ---
//============================================
/*
* A proposal cannot be neither executed nor canceled before proposal's deadline
*/
rule noExecuteOrCancelBeforeDeadline(uint256 pId, method f){
env e;
requireInvariant voteStartBeforeVoteEnd(pId);
require !isExecuted(pId) && !isCanceled(pId);
calldataarg arg;
f(e, arg);
assert e.block.number < proposalDeadline(pId) => (!isExecuted(pId) && !isCanceled(pId)), "executed/cancelled before deadline";
}
////////////////////////////////////////////////////////////////////////////////
////////////////////// Integrity Of Functions (Unit Tests) /////////////////////
////////////////////////////////////////////////////////////////////////////////
/**
* Check hashProposal hashing is reliable (different inputs lead to different buffers hashed)
*/
/*
rule checkHashProposal {
address[] t1;
address[] t2;
uint256[] v1;
uint256[] v2;
bytes[] c1;
bytes[] c2;
bytes32 d1;
bytes32 d2;
uint256 h1 = hashProposal(t1,v1,c1,d1);
uint256 h2 = hashProposal(t2,v2,c2,d2);
bool equalHashes = h1 == h2;
assert equalHashes => t1.length == t2.length;
assert equalHashes => v1.length == v2.length;
assert equalHashes => c1.length == c2.length;
assert equalHashes => d1 == d2;
}
*/
////////////////////////////////////////////////////////////////////////////////
////////////////////////////// High Level Rules ////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
///////////////////////////// Not Categorized Yet //////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/*
* all non-view functions should revert if proposal is executed
*/
// summarization - hashProposal => Const - for any set of arguments passed to the function the same value will be returned.
// that means that for different arguments passed, the same value will be returned, for example: func(a,b,c,d) == func(o,p,g,r)
// the summarization is not an under estimation in this case, because we want to check that for a specific proposal ID (pId), any
// (non view) function call is reverting. We dont care what happen with other pIds, and dont care how the hash function generates the ID.
rule allFunctionsRevertIfExecuted(method f) filtered { f -> !f.isView && f.selector != 0x7d5e81e2 && !f.isFallback && f.selector != updateQuorumNumerator(uint256).selector && f.selector != 0xa890c910} {
env e; calldataarg args; // ^ ^
uint256 pId; // propose updateTimelock
require(isExecuted(pId));
requireInvariant proposalInitiated(pId);
requireInvariant noBothExecutedAndCanceled(pId);
callFunctionWithProposal(pId, f);
assert(lastReverted, "Function was not reverted");
}
/*
* all non-view functions should revert if proposal is canceled
*/
rule allFunctionsRevertIfCanceled(method f) filtered { f -> !f.isView && f.selector != 0x7d5e81e2 && !f.isFallback && f.selector != updateQuorumNumerator(uint256).selector && f.selector != 0xa890c910} {
env e; calldataarg args; // ^ ^
uint256 pId; // propose updateTimelock
require(isCanceled(pId));
requireInvariant noBothExecutedAndCanceled(pId);
requireInvariant proposalInitiated(pId);
callFunctionWithProposal(pId, f);
assert(lastReverted, "Function was not reverted");
}
/*
* Shows that executed can only change due to execute()
*/
rule executedOnlyAfterExecuteFunc(address[] targets, uint256[] values, bytes[] calldatas, bytes32 descriptionHash, method f) {
env e; calldataarg args;
uint256 pId;
bool executedBefore = isExecuted(pId);
require(!executedBefore);
callFunctionWithProposal(pId, f);
require(!lastReverted);
// execute(e, targets, values, calldatas, descriptionHash);
bool executedAfter = isExecuted(pId);
assert(executedAfter != executedBefore, "executed property did not change");
}
/*
* User should not be able to affect proposal threshold
*/
rule unaffectedThreshhold(method f){
uint256 thresholdBefore = proposalThreshold();
env e;
calldataarg args;
f(e, args);
uint256 thresholdAfter = proposalThreshold();
assert thresholdBefore == thresholdAfter, "threshold was changed";
}