Merge pull request #9 from paritytech/stas-6-validate-block-parent-hash

Pass parent hash to the validate_block function

cumulus/runtime/src/validate_block/implementation.rs

@@ -56,14 +56,16 @@ trait Storage {
 #[cfg(not(feature = "std"))]
 #[doc(hidden)]
 pub fn validate_block<B: BlockT, E: ExecuteBlock<B>>(
-	mut block_data: &[u8],
+	mut arguments: &[u8],
 ) {
 	use codec::Decode;
 
-	let block_data = crate::ParachainBlockData::<B>::decode(&mut block_data)
+	let (parent_hash, block_data): (B::Hash, crate::ParachainBlockData::<B>) = Decode::decode(&mut arguments)
 		.expect("Could not decode parachain block.");
 	// TODO: Add `PolkadotInherent`.
 	let block = B::new(block_data.header, block_data.extrinsics);
+	assert!(parent_hash == *block.header().parent_hash(), "Invalid parent hash");
+
 	let storage = WitnessStorage::<B>::new(
 		block_data.witness_data,
 		block_data.witness_data_storage_root,

cumulus/runtime/src/validate_block/mod.rs

@@ -57,17 +57,17 @@ macro_rules! register_validate_block_impl {
 
 			#[no_mangle]
 			unsafe fn validate_block(
-				block_data: *const u8,
+				arguments: *const u8,
-				block_data_len: u64,
+				arguments_len: u64,
 			) {
-				let block_data = $crate::slice::from_raw_parts(
+				let arguments = $crate::slice::from_raw_parts(
-					block_data,
+					arguments,
-					block_data_len as usize,
+					arguments_len as usize,
 				);
 
 				$crate::validate_block::implementation::validate_block::<
 					$block, $block_executor
-				>(block_data);
+				>(arguments);
 			}
 		}
 	};

cumulus/runtime/src/validate_block/tests.rs

@@ -23,7 +23,8 @@ use runtime_primitives::traits::{Block as BlockT, Header as HeaderT};
 use executor::{WasmExecutor, error::Result, wasmi::RuntimeValue::{I64, I32}};
 use test_client::{
 	TestClientBuilder, TestClient,
-	runtime::{Block, Transfer}, TestClientBuilderExt,
+	runtime::{Block, Transfer, Hash}, TestClientBuilderExt,
+	client_ext::TestClient as _,
 };
 
 use std::collections::HashMap;
@@ -33,7 +34,7 @@ use codec::Encode;
 const WASM_CODE: &[u8] =
 	include_bytes!("../../../test/runtime/wasm/target/wasm32-unknown-unknown/release/cumulus_test_runtime.compact.wasm");
 
-fn call_validate_block(block_data: ParachainBlockData<Block>) -> Result<()> {
+fn call_validate_block(parent_hash: Hash, block_data: ParachainBlockData<Block>) -> Result<()> {
 	let mut ext = TestExternalities::default();
 	WasmExecutor::new().call_with_custom_signature(
 		&mut ext,
@@ -41,13 +42,13 @@ fn call_validate_block(block_data: ParachainBlockData<Block>) -> Result<()> {
 		&WASM_CODE,
 		"validate_block",
 		|alloc| {
-			let block_data = block_data.encode();
+			let arguments = (parent_hash, block_data).encode();
-			let block_data_offset = alloc(&block_data)?;
+			let arguments_offset = alloc(&arguments)?;
 
 			Ok(
 				vec![
-					I32(block_data_offset as i32),
+					I32(arguments_offset as i32),
-					I64(block_data.len() as i64),
+					I64(arguments.len() as i64),
 				]
 			)
 		},
@@ -131,7 +132,7 @@ fn validate_block_with_no_extrinsics() {
 		witness_data,
 		witness_data_storage_root
 	);
-	call_validate_block(block_data).expect("Calls `validate_block`");
+	call_validate_block(client.genesis_hash(), block_data).expect("Calls `validate_block`");
 }
 
 #[test]
@@ -150,5 +151,26 @@ fn validate_block_with_extrinsics() {
 		witness_data,
 		witness_data_storage_root
 	);
-	call_validate_block(block_data).expect("Calls `validate_block`");
+	call_validate_block(client.genesis_hash(), block_data).expect("Calls `validate_block`");
-}
+}
+
+#[test]
+#[should_panic]
+fn validate_block_invalid_parent_hash() {
+	let client = create_test_client();
+	let witness_data_storage_root = *client
+		.best_block_header()
+		.expect("Best block exists")
+		.state_root();
+	let (block, witness_data) = build_block_with_proof(&client, Vec::new());
+	let (mut header, extrinsics) = block.deconstruct();
+	header.set_parent_hash(Hash::from_low_u64_be(1));
+
+	let block_data = ParachainBlockData::new(
+		header,
+		extrinsics,
+		witness_data,
+		witness_data_storage_root
+	);
+	call_validate_block(client.genesis_hash(), block_data).expect("Calls `validate_block`");
+}