dexorder

2024-10-17 02:42:28 -04:00
commit 25def69c66
878 changed files with 112489 additions and 0 deletions
--- a/lib_openzeppelin_contracts/certora/specs/ERC20.spec
+++ b/lib_openzeppelin_contracts/certora/specs/ERC20.spec
@@ -0,0 +1,352 @@
+import "helpers/helpers.spec";
+import "methods/IERC20.spec";
+import "methods/IERC2612.spec";
+
+methods {
+    // exposed for FV
+    function mint(address,uint256) external;
+    function burn(address,uint256) external;
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Ghost & hooks: sum of all balances                                                                                  │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+ghost mathint sumOfBalances {
+    init_state axiom sumOfBalances == 0;
+}
+
+// Because `balance` has a uint256 type, any balance addition in CVL1 behaved as a `require_uint256()` casting,
+// leaving out the possibility of overflow. This is not the case in CVL2 where casting became more explicit.
+// A counterexample in CVL2 is having an initial state where Alice initial balance is larger than totalSupply, which 
+// overflows Alice's balance when receiving a transfer. This is not possible unless the contract is deployed into an 
+// already used address (or upgraded from corrupted state).
+// We restrict such behavior by making sure no balance is greater than the sum of balances.
+hook Sload uint256 balance _balances[KEY address addr] STORAGE {
+    require sumOfBalances >= to_mathint(balance);
+}
+
+hook Sstore _balances[KEY address addr] uint256 newValue (uint256 oldValue) STORAGE {
+    sumOfBalances = sumOfBalances - oldValue + newValue;
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Invariant: totalSupply is the sum of all balances                                                                   │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+invariant totalSupplyIsSumOfBalances()
+    to_mathint(totalSupply()) == sumOfBalances;
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Invariant: balance of address(0) is 0                                                                               │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+invariant zeroAddressNoBalance()
+    balanceOf(0) == 0;
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rules: only mint and burn can change total supply                                                                   │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule noChangeTotalSupply(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+
+    method f;
+    calldataarg args;
+
+    uint256 totalSupplyBefore = totalSupply();
+    f(e, args);
+    uint256 totalSupplyAfter = totalSupply();
+
+    assert totalSupplyAfter > totalSupplyBefore => f.selector == sig:mint(address,uint256).selector;
+    assert totalSupplyAfter < totalSupplyBefore => f.selector == sig:burn(address,uint256).selector;
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rules: only the token holder or an approved third party can reduce an account's balance                             │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule onlyAuthorizedCanTransfer(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+
+    method f;
+    calldataarg args;
+    address account;
+
+    uint256 allowanceBefore = allowance(account, e.msg.sender);
+    uint256 balanceBefore   = balanceOf(account);
+    f(e, args);
+    uint256 balanceAfter    = balanceOf(account);
+
+    assert (
+        balanceAfter < balanceBefore
+    ) => (
+        f.selector == sig:burn(address,uint256).selector ||
+        e.msg.sender == account ||
+        balanceBefore - balanceAfter <= to_mathint(allowanceBefore)
+    );
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rules: only the token holder (or a permit) can increase allowance. The spender can decrease it by using it          │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule onlyHolderOfSpenderCanChangeAllowance(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+
+    method f;
+    calldataarg args;
+    address holder;
+    address spender;
+
+    uint256 allowanceBefore = allowance(holder, spender);
+    f(e, args);
+    uint256 allowanceAfter = allowance(holder, spender);
+
+    assert (
+        allowanceAfter > allowanceBefore
+    ) => (
+        (f.selector == sig:approve(address,uint256).selector           && e.msg.sender == holder) ||
+        (f.selector == sig:permit(address,address,uint256,uint256,uint8,bytes32,bytes32).selector)
+    );
+
+    assert (
+        allowanceAfter < allowanceBefore
+    ) => (
+        (f.selector == sig:transferFrom(address,address,uint256).selector && e.msg.sender == spender) ||
+        (f.selector == sig:approve(address,uint256).selector              && e.msg.sender == holder ) ||
+        (f.selector == sig:permit(address,address,uint256,uint256,uint8,bytes32,bytes32).selector)
+    );
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rules: mint behavior and side effects                                                                               │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule mint(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+    require nonpayable(e);
+
+    address to;
+    address other;
+    uint256 amount;
+
+    // cache state
+    uint256 toBalanceBefore    = balanceOf(to);
+    uint256 otherBalanceBefore = balanceOf(other);
+    uint256 totalSupplyBefore  = totalSupply();
+
+    // run transaction
+    mint@withrevert(e, to, amount);
+
+    // check outcome
+    if (lastReverted) {
+        assert to == 0 || totalSupplyBefore + amount > max_uint256;
+    } else {
+        // updates balance and totalSupply
+        assert to_mathint(balanceOf(to)) == toBalanceBefore   + amount;
+        assert to_mathint(totalSupply()) == totalSupplyBefore + amount;
+
+        // no other balance is modified
+        assert balanceOf(other) != otherBalanceBefore => other == to;
+    }
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rules: burn behavior and side effects                                                                               │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule burn(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+    require nonpayable(e);
+
+    address from;
+    address other;
+    uint256 amount;
+
+    // cache state
+    uint256 fromBalanceBefore  = balanceOf(from);
+    uint256 otherBalanceBefore = balanceOf(other);
+    uint256 totalSupplyBefore  = totalSupply();
+
+    // run transaction
+    burn@withrevert(e, from, amount);
+
+    // check outcome
+    if (lastReverted) {
+        assert from == 0 || fromBalanceBefore < amount;
+    } else {
+        // updates balance and totalSupply
+        assert to_mathint(balanceOf(from)) == fromBalanceBefore   - amount;
+        assert to_mathint(totalSupply())   == totalSupplyBefore - amount;
+
+        // no other balance is modified
+        assert balanceOf(other) != otherBalanceBefore => other == from;
+    }
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rule: transfer behavior and side effects                                                                            │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule transfer(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+    require nonpayable(e);
+
+    address holder = e.msg.sender;
+    address recipient;
+    address other;
+    uint256 amount;
+
+    // cache state
+    uint256 holderBalanceBefore    = balanceOf(holder);
+    uint256 recipientBalanceBefore = balanceOf(recipient);
+    uint256 otherBalanceBefore     = balanceOf(other);
+
+    // run transaction
+    transfer@withrevert(e, recipient, amount);
+
+    // check outcome
+    if (lastReverted) {
+        assert holder == 0 || recipient == 0 || amount > holderBalanceBefore;
+    } else {
+        // balances of holder and recipient are updated
+        assert to_mathint(balanceOf(holder))    == holderBalanceBefore    - (holder == recipient ? 0 : amount);
+        assert to_mathint(balanceOf(recipient)) == recipientBalanceBefore + (holder == recipient ? 0 : amount);
+
+        // no other balance is modified
+        assert balanceOf(other) != otherBalanceBefore => (other == holder || other == recipient);
+    }
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rule: transferFrom behavior and side effects                                                                        │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule transferFrom(env e) {
+    requireInvariant totalSupplyIsSumOfBalances();
+    require nonpayable(e);
+
+    address spender = e.msg.sender;
+    address holder;
+    address recipient;
+    address other;
+    uint256 amount;
+
+    // cache state
+    uint256 allowanceBefore        = allowance(holder, spender);
+    uint256 holderBalanceBefore    = balanceOf(holder);
+    uint256 recipientBalanceBefore = balanceOf(recipient);
+    uint256 otherBalanceBefore     = balanceOf(other);
+
+    // run transaction
+    transferFrom@withrevert(e, holder, recipient, amount);
+
+    // check outcome
+    if (lastReverted) {
+        assert holder == 0 || recipient == 0 || spender == 0 || amount > holderBalanceBefore || amount > allowanceBefore;
+    } else {
+        // allowance is valid & updated
+        assert allowanceBefore            >= amount;
+        assert to_mathint(allowance(holder, spender)) == (allowanceBefore == max_uint256 ? max_uint256 : allowanceBefore - amount);
+
+        // balances of holder and recipient are updated
+        assert to_mathint(balanceOf(holder))    == holderBalanceBefore    - (holder == recipient ? 0 : amount);
+        assert to_mathint(balanceOf(recipient)) == recipientBalanceBefore + (holder == recipient ? 0 : amount);
+
+        // no other balance is modified
+        assert balanceOf(other) != otherBalanceBefore => (other == holder || other == recipient);
+    }
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rule: approve behavior and side effects                                                                             │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule approve(env e) {
+    require nonpayable(e);
+
+    address holder = e.msg.sender;
+    address spender;
+    address otherHolder;
+    address otherSpender;
+    uint256 amount;
+
+    // cache state
+    uint256 otherAllowanceBefore = allowance(otherHolder, otherSpender);
+
+    // run transaction
+    approve@withrevert(e, spender, amount);
+
+    // check outcome
+    if (lastReverted) {
+        assert holder == 0 || spender == 0;
+    } else {
+        // allowance is updated
+        assert allowance(holder, spender) == amount;
+
+        // other allowances are untouched
+        assert allowance(otherHolder, otherSpender) != otherAllowanceBefore => (otherHolder == holder && otherSpender == spender);
+    }
+}
+
+/*
+┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Rule: permit behavior and side effects                                                                              │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+*/
+rule permit(env e) {
+    require nonpayable(e);
+
+    address holder;
+    address spender;
+    uint256 amount;
+    uint256 deadline;
+    uint8 v;
+    bytes32 r;
+    bytes32 s;
+
+    address account1;
+    address account2;
+    address account3;
+
+    // cache state
+    uint256 nonceBefore          = nonces(holder);
+    uint256 otherNonceBefore     = nonces(account1);
+    uint256 otherAllowanceBefore = allowance(account2, account3);
+
+    // sanity: nonce overflow, which possible in theory, is assumed to be impossible in practice
+    require nonceBefore      < max_uint256;
+    require otherNonceBefore < max_uint256;
+
+    // run transaction
+    permit@withrevert(e, holder, spender, amount, deadline, v, r, s);
+
+    // check outcome
+    if (lastReverted) {
+        // Without formally checking the signature, we can't verify exactly the revert causes
+        assert true;
+    } else {
+        // allowance and nonce are updated
+        assert allowance(holder, spender) == amount;
+        assert to_mathint(nonces(holder)) == nonceBefore + 1;
+
+        // deadline was respected
+        assert deadline >= e.block.timestamp;
+
+        // no other allowance or nonce is modified
+        assert nonces(account1)              != otherNonceBefore     => account1 == holder;
+        assert allowance(account2, account3) != otherAllowanceBefore => (account2 == holder && account3 == spender);
+    }
+}