[stable] Refactor static context check in CREATE (#6889)

* Refactor static context check in CREATE.

* Fix evm tests.

ethcore/evm/src/ext.rs

@@ -30,9 +30,6 @@ pub enum ContractCreateResult {
 	/// Returned when contract creation failed.
 	/// VM doesn't have to know the reason.
 	Failed,
-	/// Returned when contract creation failed.
-	/// VM doesn't have to know the reason.
-	FailedInStaticCall,
 	/// Reverted with REVERT.
 	Reverted(U256, ReturnData),
 }

ethcore/evm/src/interpreter/mod.rs

@@ -313,20 +313,24 @@ impl<Cost: CostType> Interpreter<Cost> {
 				let init_off = stack.pop_back();
 				let init_size = stack.pop_back();
 
-				let address_scheme = if instruction == instructions::CREATE { CreateContractAddress::FromSenderAndNonce } else { CreateContractAddress::FromSenderAndCodeHash };
 				let create_gas = provided.expect("`provided` comes through Self::exec from `Gasometer::get_gas_cost_mem`; `gas_gas_mem_cost` guarantees `Some` when instruction is `CALL`/`CALLCODE`/`DELEGATECALL`/`CREATE`; this is `CREATE`; qed");
 
-				let contract_code = self.mem.read_slice(init_off, init_size);
-				let can_create = ext.balance(&params.address)? >= endowment && ext.depth() < ext.schedule().max_depth;
+				if ext.is_static() {
+					return Err(evm::Error::MutableCallInStaticContext);
+				}
 
 				// clear return data buffer before creating new call frame.
 				self.return_data = ReturnData::empty();
 
+				let can_create = ext.balance(&params.address)? >= endowment && ext.depth() < ext.schedule().max_depth;
 				if !can_create {
 					stack.push(U256::zero());
 					return Ok(InstructionResult::UnusedGas(create_gas));
 				}
 
+				let contract_code = self.mem.read_slice(init_off, init_size);
+				let address_scheme = if instruction == instructions::CREATE { CreateContractAddress::FromSenderAndNonce } else { CreateContractAddress::FromSenderAndCodeHash };
+
 				let create_result = ext.create(&create_gas.as_u256(), &endowment, contract_code, address_scheme);
 				return match create_result {
 					ContractCreateResult::Created(address, gas_left) => {
@@ -342,9 +346,6 @@ impl<Cost: CostType> Interpreter<Cost> {
 						stack.push(U256::zero());
 						Ok(InstructionResult::Ok)
 					},
-					ContractCreateResult::FailedInStaticCall => {
-						Err(evm::Error::MutableCallInStaticContext)
-					},
 				};
 			},
 			instructions::CALL | instructions::CALLCODE | instructions::DELEGATECALL | instructions::STATICCALL => {
@@ -906,8 +907,8 @@ mod tests {
 	use rustc_hex::FromHex;
 	use vmtype::VMType;
 	use factory::Factory;
-	use vm::{self, ActionParams, ActionValue};
-	use vm::tests::{FakeExt, test_finalize};
+	use action_params::{ActionParams, ActionValue};
+	use ::tests::{FakeExt, test_finalize};
 
 	#[test]
 	fn should_not_fail_on_tracing_mem() {
@@ -950,6 +951,6 @@ mod tests {
 			test_finalize(vm.exec(params, &mut ext)).err().unwrap()
 		};
 
-		assert_eq!(err, ::vm::Error::OutOfBounds);
+		assert_eq!(err, ::Error::OutOfBounds);
 	}
 }

ethcore/evm/src/tests.rs

@@ -55,18 +55,20 @@ pub struct FakeExt {
 	pub store: HashMap<H256, H256>,
 	pub suicides: HashSet<Address>,
 	pub calls: HashSet<FakeCall>,
-	sstore_clears: usize,
-	depth: usize,
-	blockhashes: HashMap<U256, H256>,
-	codes: HashMap<Address, Arc<Bytes>>,
-	logs: Vec<FakeLogEntry>,
-	info: EnvInfo,
-	schedule: Schedule,
-	balances: HashMap<Address, U256>,
+	pub sstore_clears: usize,
+	pub depth: usize,
+	pub blockhashes: HashMap<U256, H256>,
+	pub codes: HashMap<Address, Arc<Bytes>>,
+	pub logs: Vec<FakeLogEntry>,
+	pub info: EnvInfo,
+	pub schedule: Schedule,
+	pub balances: HashMap<Address, U256>,
+	pub is_static: bool,
+	pub tracing: bool,
 }
 
 // similar to the normal `finalize` function, but ignoring NeedsReturn.
-fn test_finalize(res: Result<GasLeft, evm::Error>) -> Result<U256, evm::Error> {
+pub fn test_finalize(res: Result<GasLeft, evm::Error>) -> Result<U256, evm::Error> {
 	match res {
 		Ok(GasLeft::Known(gas)) => Ok(gas),
 		Ok(GasLeft::NeedsReturn{..}) => unimplemented!(), // since ret is unimplemented.
@@ -78,6 +80,12 @@ impl FakeExt {
 	pub fn new() -> Self {
 		FakeExt::default()
 	}
+
+	pub fn new_byzantium() -> Self {
+		let mut ext = FakeExt::new();
+		ext.schedule = Schedule::new_byzantium();
+		ext
+	}
 }
 
 impl Default for Schedule {
@@ -168,7 +176,7 @@ impl Ext for FakeExt {
 		Ok(())
 	}
 
-	fn ret(self, _gas: &U256, _data: &ReturnData) -> evm::Result<U256> {
+	fn ret(self, _gas: &U256, _data: &ReturnData, _apply_state: bool) -> evm::Result<U256> {
 		unimplemented!();
 	}
 
@@ -192,6 +200,10 @@ impl Ext for FakeExt {
 	fn inc_sstore_clears(&mut self) {
 		self.sstore_clears += 1;
 	}
+
+	fn is_static(&self) -> bool {
+		self.is_static
+	}
 }
 
 #[test]
@@ -917,7 +929,6 @@ fn test_jumps(factory: super::Factory) {
 	assert_eq!(gas_left, U256::from(54_117));
 }
 
-
 evm_test!{test_calls: test_calls_jit, test_calls_int}
 fn test_calls(factory: super::Factory) {
 	let code = "600054602d57600160005560006000600060006050610998610100f160006000600060006050610998610100f25b".from_hex().unwrap();
@@ -962,6 +973,27 @@ fn test_calls(factory: super::Factory) {
 	assert_eq!(ext.calls.len(), 2);
 }
 
+evm_test!{test_create_in_staticcall: test_create_in_staticcall_jit, test_create_in_staticcall_int}
+fn test_create_in_staticcall(factory: super::Factory) {
+	let code = "600060006064f000".from_hex().unwrap();
+
+	let address = Address::from(0x155);
+	let mut params = ActionParams::default();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(code));
+	params.address = address.clone();
+	let mut ext = FakeExt::new_byzantium();
+	ext.is_static = true;
+
+	let err = {
+		let mut vm = factory.create(params.gas);
+		test_finalize(vm.exec(params, &mut ext)).unwrap_err()
+	};
+
+	assert_eq!(err, ::Error::MutableCallInStaticContext);
+	assert_eq!(ext.calls.len(), 0);
+}
+
 fn assert_set_contains<T : Debug + Eq + PartialEq + Hash>(set: &HashSet<T>, val: &T) {
 	let contains = set.contains(val);
 	if !contains {

ethcore/evm/src/wasm/runtime.rs

@@ -169,10 +169,6 @@ impl<'a> Runtime<'a> {
 				self.gas_counter = self.gas_limit - gas_left.low_u64();
 				Ok(Some((-1i32).into()))
 			},
-			ext::ContractCreateResult::FailedInStaticCall => {
-				trace!(target: "wasm", "runtime: create contract called in static context");
-				Err(interpreter::Error::Trap("CREATE in static context".to_owned()))
-			},
 		}
 	}
 

ethcore/src/externalities.rs

@@ -234,8 +234,6 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 			Ok(FinalizationResult{ gas_left, apply_state: false, return_data }) => {
 				ContractCreateResult::Reverted(gas_left, return_data)
 			},
-			Err(evm::Error::MutableCallInStaticContext) => ContractCreateResult::FailedInStaticCall,
-			_ => ContractCreateResult::Failed,
 		}
 	}
 

scripts/targets.sh

@@ -19,4 +19,5 @@ export TARGETS="
 	-p ethcore-ipc-tests \
 	-p ethcore-ipc-nano \
 	-p ethcore-light \
+	-p evm \
 	-p parity"