Merge pull request #6507 from ethereum/smt_address_members

[SMTChecker] Address members
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chriseth 2019-04-25 17:29:42 +02:00 committed by GitHub
commit 169b555a22
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14 changed files with 233 additions and 4 deletions

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@ -19,6 +19,7 @@ Compiler Features:
* SMTChecker: Support mod.
* SMTChecker: Support ``contract`` type.
* SMTChecker: Support ``this`` as address.
* SMTChecker: Support address members.
* Optimizer: Add rule for shifts by constants larger than 255 for Constantinople.
* Optimizer: Add rule to simplify certain ANDs and SHL combinations
* Yul: Adds break and continue keywords to for-loop syntax.

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@ -28,14 +28,58 @@ EncodingContext::EncodingContext(SolverInterface& _solver):
m_solver(_solver),
m_thisAddress(make_unique<SymbolicAddressVariable>("this", m_solver))
{
auto sort = make_shared<smt::ArraySort>(
make_shared<smt::Sort>(smt::Kind::Int),
make_shared<smt::Sort>(smt::Kind::Int)
);
m_balances = make_unique<SymbolicVariable>(sort, "balances", m_solver);
}
void EncodingContext::reset()
{
m_thisAddress->increaseIndex();
m_balances->increaseIndex();
}
smt::Expression EncodingContext::thisAddress()
{
return m_thisAddress->currentValue();
}
smt::Expression EncodingContext::balance()
{
return balance(m_thisAddress->currentValue());
}
smt::Expression EncodingContext::balance(smt::Expression _address)
{
return smt::Expression::select(m_balances->currentValue(), move(_address));
}
void EncodingContext::transfer(smt::Expression _from, smt::Expression _to, smt::Expression _value)
{
unsigned indexBefore = m_balances->index();
addBalance(_from, 0 - _value);
addBalance(_to, move(_value));
unsigned indexAfter = m_balances->index();
solAssert(indexAfter > indexBefore, "");
m_balances->increaseIndex();
/// Do not apply the transfer operation if _from == _to.
auto newBalances = smt::Expression::ite(
move(_from) == move(_to),
m_balances->valueAtIndex(indexBefore),
m_balances->valueAtIndex(indexAfter)
);
m_solver.addAssertion(m_balances->currentValue() == newBalances);
}
void EncodingContext::addBalance(smt::Expression _address, smt::Expression _value)
{
auto newBalances = smt::Expression::store(
m_balances->currentValue(),
_address,
balance(_address) + move(_value)
);
m_balances->increaseIndex();
m_solver.addAssertion(newBalances == m_balances->currentValue());
}

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@ -41,12 +41,24 @@ public:
/// Value of `this` address.
smt::Expression thisAddress();
/// @returns the symbolic balance of address `this`.
smt::Expression balance();
/// @returns the symbolic balance of an address.
smt::Expression balance(smt::Expression _address);
/// Transfer _value from _from to _to.
void transfer(smt::Expression _from, smt::Expression _to, smt::Expression _value);
private:
/// Adds _value to _account's balance.
void addBalance(smt::Expression _account, smt::Expression _value);
SolverInterface& m_solver;
/// Symbolic `this` address.
std::unique_ptr<SymbolicAddressVariable> m_thisAddress;
/// Symbolic balances.
std::unique_ptr<SymbolicVariable> m_balances;
};
}

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@ -112,6 +112,7 @@ bool SMTChecker::visit(FunctionDefinition const& _function)
if (isRootFunction())
{
m_interface->reset();
m_context.reset();
m_pathConditions.clear();
m_callStack.clear();
m_expressions.clear();
@ -609,6 +610,12 @@ void SMTChecker::endVisit(FunctionCall const& _funCall)
popCallStack();
break;
case FunctionType::Kind::External:
case FunctionType::Kind::DelegateCall:
case FunctionType::Kind::BareCall:
case FunctionType::Kind::BareCallCode:
case FunctionType::Kind::BareDelegateCall:
case FunctionType::Kind::BareStaticCall:
case FunctionType::Kind::Creation:
m_externalFunctionCallHappened = true;
resetStateVariables();
resetStorageReferences();
@ -622,6 +629,22 @@ void SMTChecker::endVisit(FunctionCall const& _funCall)
case FunctionType::Kind::MulMod:
abstractFunctionCall(_funCall);
break;
case FunctionType::Kind::Send:
case FunctionType::Kind::Transfer:
{
auto const& memberAccess = dynamic_cast<MemberAccess const&>(_funCall.expression());
auto const& address = memberAccess.expression();
auto const& value = args.at(0);
solAssert(value, "");
smt::Expression thisBalance = m_context.balance();
setSymbolicUnknownValue(thisBalance, TypeProvider::uint256(), *m_interface);
checkCondition(thisBalance < expr(*value), _funCall.location(), "Insufficient funds", "address(this).balance", &thisBalance);
m_context.transfer(m_context.thisAddress(), expr(address), expr(*value));
createExpr(_funCall);
break;
}
default:
m_errorReporter.warning(
_funCall.location(),
@ -874,6 +897,17 @@ bool SMTChecker::visit(MemberAccess const& _memberAccess)
}
return false;
}
else if (exprType->category() == Type::Category::Address)
{
_memberAccess.expression().accept(*this);
if (_memberAccess.memberName() == "balance")
{
defineExpr(_memberAccess, m_context.balance(expr(_memberAccess.expression())));
setSymbolicUnknownValue(*m_expressions[&_memberAccess], *m_interface);
m_uninterpretedTerms.insert(&_memberAccess);
return false;
}
}
else
m_errorReporter.warning(
_memberAccess.location(),

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@ -286,6 +286,7 @@ private:
std::unordered_map<Expression const*, std::shared_ptr<SymbolicVariable>> m_expressions;
std::unordered_map<VariableDeclaration const*, std::shared_ptr<SymbolicVariable>> m_variables;
std::unordered_map<std::string, std::shared_ptr<SymbolicVariable>> m_globalContext;
/// Stores the instances of an Uninterpreted Function applied to arguments.
/// These may be direct application of UFs or Array index access.
/// Used to retrieve models.

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@ -0,0 +1,13 @@
pragma experimental SMTChecker;
contract C
{
function f(address a, address b) public view {
uint x = b.balance + 1000 ether;
assert(a.balance > b.balance);
}
}
// ----
// Warning: (96-102): Unused local variable.
// Warning: (131-160): Assertion violation happens here
// Warning: (105-127): Overflow (resulting value larger than 2**256 - 1) happens here

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@ -0,0 +1,23 @@
pragma experimental SMTChecker;
contract C
{
uint x;
mapping (uint => uint) map;
function f(address a, bytes memory data) public {
x = 0;
map[0] = 0;
mapping (uint => uint) storage localMap = map;
(bool success, bytes memory ret) = a.call(data);
assert(success);
assert(x == 0);
assert(map[0] == 0);
assert(localMap[0] == 0);
}
}
// ====
// EVMVersion: >spuriousDragon
// ----
// Warning: (224-240): Unused local variable.
// Warning: (209-256): Assertion checker does not yet support such variable declarations.
// Warning: (260-275): Assertion violation happens here

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@ -0,0 +1,23 @@
pragma experimental SMTChecker;
contract C
{
uint x;
mapping (uint => uint) map;
function f(address a, bytes memory data) public {
x = 0;
map[0] = 0;
mapping (uint => uint) storage localMap = map;
(bool success, bytes memory ret) = a.delegatecall(data);
assert(success);
assert(x == 0);
assert(map[0] == 0);
assert(localMap[0] == 0);
}
}
// ====
// EVMVersion: >spuriousDragon
// ----
// Warning: (224-240): Unused local variable.
// Warning: (209-264): Assertion checker does not yet support such variable declarations.
// Warning: (268-283): Assertion violation happens here

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@ -0,0 +1,23 @@
pragma experimental SMTChecker;
contract C
{
uint x;
mapping (uint => uint) map;
function f(address a, bytes memory data) public {
x = 0;
map[0] = 0;
mapping (uint => uint) storage localMap = map;
(bool success, bytes memory ret) = a.staticcall(data);
assert(success);
assert(x == 0);
assert(map[0] == 0);
assert(localMap[0] == 0);
}
}
// ====
// EVMVersion: >spuriousDragon
// ----
// Warning: (224-240): Unused local variable.
// Warning: (209-262): Assertion checker does not yet support such variable declarations.
// Warning: (266-281): Assertion violation happens here

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@ -0,0 +1,16 @@
pragma experimental SMTChecker;
contract C
{
function f(address payable a) public {
uint x = 100;
require(x == a.balance);
a.transfer(600);
// This fails since a == this is possible.
assert(a.balance == 700);
}
}
// ----
// Warning: (131-146): Insufficient funds happens here
// Warning: (131-146): Assertion checker does not yet implement this type.
// Warning: (195-219): Assertion violation happens here

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@ -0,0 +1,21 @@
pragma experimental SMTChecker;
contract C
{
function f(uint x, address payable a, address payable b) public {
require(a != b);
require(x == 100);
require(x == a.balance);
require(a.balance == b.balance);
a.transfer(600);
b.transfer(100);
// Fails since a == this is possible.
assert(a.balance > b.balance);
}
}
// ----
// Warning: (217-232): Insufficient funds happens here
// Warning: (217-232): Assertion checker does not yet implement this type.
// Warning: (236-251): Insufficient funds happens here
// Warning: (236-251): Assertion checker does not yet implement this type.
// Warning: (295-324): Assertion violation happens here

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@ -0,0 +1,18 @@
pragma experimental SMTChecker;
contract C
{
function f(address payable a, address payable b) public {
require(a.balance == 0);
a.transfer(600);
b.transfer(1000);
// Fails since a == this is possible.
assert(a.balance == 600);
}
}
// ----
// Warning: (134-149): Insufficient funds happens here
// Warning: (134-149): Assertion checker does not yet implement this type.
// Warning: (153-169): Insufficient funds happens here
// Warning: (153-169): Assertion checker does not yet implement this type.
// Warning: (213-237): Assertion violation happens here

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@ -3,9 +3,9 @@
{
"smtlib2responses":
{
"0x47826ec8b83cfec30171b34f944aed6c33ecd12f02b9ad522ca45317c9bd5f45": "sat\n((|EVALEXPR_0| 1))",
"0x734c058efe9d6ec224de3cf2bdfa6c936a1c9c159c040c128d631145b2fed195": "unsat\n",
"0xa0c072acdbe5181dd56cbad8960cb5bb0b9e97fd598cfd895467bd73bbcca028": "sat\n((|EVALEXPR_0| 0))"
"0x47a038dd9021ecb218726ea6bf1f75c215a50b1981bae4341e89c9f2b7ac5db7": "sat\n((|EVALEXPR_0| 1))",
"0xf057b272f2ceb99a2f714cb132960babdeedfb84ff8ffb96106a58bc0c2060cb": "sat\n((|EVALEXPR_0| 0))",
"0xf49b9d0eb7b6d2f2ac9e1604288e52ee1a08cda57058e26d7843ed109ca6d7c9": "unsat\n"
}
}
}

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@ -3,7 +3,7 @@
{
"smtlib2responses":
{
"0xa0c072acdbe5181dd56cbad8960cb5bb0b9e97fd598cfd895467bd73bbcca028": "sat\n((|EVALEXPR_0| 0))\n"
"0xf057b272f2ceb99a2f714cb132960babdeedfb84ff8ffb96106a58bc0c2060cb": "sat\n((|EVALEXPR_0| 0))\n"
}
}
}