staking/certora/specs/StakeVault.spec

100 lines
4.0 KiB
Ruby

using ERC20A as staked;
using StakeManager as stakeManager;
methods {
function ERC20A.balanceOf(address) external returns (uint256) envfree;
function ERC20A.allowance(address, address) external returns(uint256) envfree;
function ERC20A.totalSupply() external returns(uint256) envfree;
function StakeManager.accounts(address) external returns(address, uint256, uint256, uint256, uint256, uint256, uint256) envfree;
function _.migrateFrom(address, bool, StakeManager.Account) external => DISPATCHER(true);
function _.increaseTotalMP(uint256) external => DISPATCHER(true);
function _.owner() external => DISPATCHER(true);
function Math.mulDiv(uint256 a, uint256 b, uint256 c) internal returns uint256 => mulDivSummary(a,b,c);
}
function mulDivSummary(uint256 a, uint256 b, uint256 c) returns uint256 {
require c != 0;
return require_uint256(a*b/c);
}
function getAccountBalance(address addr) returns uint256 {
uint256 balance;
_, balance, _, _, _, _, _ = stakeManager.accounts(addr);
return balance;
}
definition isMigrationFunction(method f) returns bool = (
f.selector == sig:stakeManager.migrationInitialize(uint256,uint256,uint256,uint256).selector ||
f.selector == sig:stakeManager.migrateFrom(address,bool,StakeManager.Account).selector ||
f.selector == sig:stakeManager.increaseTotalMP(uint256).selector ||
f.selector == sig:stakeManager.startMigration(address).selector
);
// check that the ERC20.balanceOf(vault) is >= to StakeManager.accounts[a].balance
invariant accountBalanceVsERC20Balance()
staked.balanceOf(currentContract) >= getAccountBalance(currentContract)
filtered {
m -> m.selector != sig:leave().selector && !isMigrationFunction(m)
}
{ preserved with (env e) {
// the sender can't be the vault otherwise it can transfer tokens
require e.msg.sender != currentContract;
// nobody has allowance to spend the tokens of the vault
require staked.allowance(currentContract, e.msg.sender) == 0;
// if it's a generic transfer to the vault, it can't overflow
require staked.balanceOf(currentContract) + staked.balanceOf(e.msg.sender) <= to_mathint(staked.totalSupply());
// if it's a transfer from the StakeManager to the vault as reward address, it can't overflow
require staked.balanceOf(currentContract) + staked.balanceOf(stakeManager) <= to_mathint(staked.totalSupply());
}
// the next blocked is run instead of the general one if the current function is staked.transferFrom.
// if it's a transferFrom, we don't have the from in the first preserved block to check for an overflow
preserved staked.transferFrom(address from, address to, uint256 amount) with (env e) {
// if the msg.sender is the vault than it would be able to move tokens.
// it would be possible only if the Vault contract called the ERC20.transferFrom.
require e.msg.sender != currentContract;
// no one has allowance to move tokens owned by the vault
require staked.allowance(currentContract, e.msg.sender) == 0;
require staked.balanceOf(from) + staked.balanceOf(to) <= to_mathint(staked.totalSupply());
}
preserved stake(uint256 amount, uint256 duration) with (env e) {
require e.msg.sender != currentContract;
require staked.balanceOf(currentContract) + staked.balanceOf(e.msg.sender) + staked.balanceOf(stakeManager) <= to_mathint(staked.totalSupply());
}
}
/* assume that migration is zero, causing to ignore cases where it is not zero */
function simplification() {
require stakeManager.migration == 0;
}
rule reachability(method f) filtered { f -> !isMigrationFunction(f) }
{
calldataarg args;
env e;
f(e,args);
satisfy true;
}
/*
The rule below is commented out as it's merely used to easily have the
prover find all functions that change balances.
rule whoChangeERC20Balance(method f)
{
simplification();
address user;
uint256 before = staked.balanceOf(user);
calldataarg args;
env e;
f(e,args);
assert before == staked.balanceOf(user);
}
*/