remove WASM_MAGIC (#2832)

* remove WASM_MAGIC

* fix test warnings

polkadot/runtime/common/src/integration_tests.rs

@@ -259,12 +259,7 @@ fn test_genesis_head(size: usize) -> HeadData {
 }
 
 fn test_validation_code(size: usize) -> ValidationCode {
-	let mut validation_code = vec![0u8; size as usize];
-	// Replace first bytes of code with "WASM_MAGIC" to pass validation test.
-	let _ = validation_code.splice(
-		..crate::WASM_MAGIC.len(),
-		crate::WASM_MAGIC.iter().cloned(),
-	).collect::<Vec<_>>();
+	let validation_code = vec![0u8; size as usize];
 	ValidationCode(validation_code)
 }
 

polkadot/runtime/common/src/lib.rs

@@ -59,10 +59,6 @@ pub use impls::ToAuthor;
 
 pub type NegativeImbalance<T> = <pallet_balances::Pallet<T> as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
 
-/// The sequence of bytes a valid wasm module binary always starts with. Apart from that it's also a
-/// valid wasm module.
-pub const WASM_MAGIC: &[u8] = &[0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00];
-
 /// We assume that an on-initialize consumes 1% of the weight on average, hence a single extrinsic
 /// will not be allowed to consume more than `AvailableBlockRatio - 1%`.
 pub const AVERAGE_ON_INITIALIZE_RATIO: Perbill = Perbill::from_percent(1);

polkadot/runtime/common/src/mock.rs

@@ -160,12 +160,7 @@ impl<T: frame_system::Config> Registrar for TestRegistrar<T> {
 
 	#[cfg(test)]
 	fn worst_validation_code() -> ValidationCode {
-		let mut validation_code = vec![0u8; 1000];
-		// Replace first bytes of code with "WASM_MAGIC" to pass validation test.
-		let _ = validation_code.splice(
-			..crate::WASM_MAGIC.len(),
-			crate::WASM_MAGIC.iter().cloned(),
-		).collect::<Vec<_>>();
+		let validation_code = vec![0u8; 1000];
 		validation_code.into()
 	}
 

polkadot/runtime/common/src/paras_registrar.rs

@@ -17,7 +17,6 @@
 //! Module to handle parathread/parachain registration and related fund management.
 //! In essence this is a simple wrapper around `paras`.
 
-use crate::WASM_MAGIC;
 use sp_std::{prelude::*, result};
 use frame_support::{
 	decl_storage, decl_module, decl_error, decl_event, ensure,
@@ -133,8 +132,6 @@ decl_error! {
 		CodeTooLarge,
 		/// Invalid para head data size.
 		HeadDataTooLarge,
-		/// The validation code provided doesn't start with the Wasm file magic string.
-		DefinitelyNotWasm,
 		/// Para is not a Parachain.
 		NotParachain,
 		/// Para is not a Parathread.
@@ -304,12 +301,7 @@ impl<T: Config> Registrar for Module<T> {
 	fn worst_validation_code() -> ValidationCode {
 		// TODO: Figure a way to allow bigger wasm in benchmarks?
 		let max_code_size = (T::MaxCodeSize::get()).min(4 * 1024 * 1024);
-		let mut validation_code = vec![0u8; max_code_size as usize];
-		// Replace first bytes of code with "WASM_MAGIC" to pass validation test.
-		let _ = validation_code.splice(
-			..crate::WASM_MAGIC.len(),
-			crate::WASM_MAGIC.iter().cloned(),
-		).collect::<Vec<_>>();
+		let validation_code = vec![0u8; max_code_size as usize];
 		validation_code.into()
 	}
 
@@ -378,7 +370,6 @@ impl<T: Config> Module<T> {
 	) -> Result<(ParaGenesisArgs, BalanceOf<T>), sp_runtime::DispatchError> {
 		ensure!(validation_code.0.len() <= T::MaxCodeSize::get() as usize, Error::<T>::CodeTooLarge);
 		ensure!(genesis_head.0.len() <= T::MaxHeadSize::get() as usize, Error::<T>::HeadDataTooLarge);
-		ensure!(validation_code.0.starts_with(WASM_MAGIC), Error::<T>::DefinitelyNotWasm);
 
 		let per_byte_fee = T::DataDepositPerByte::get();
 		let deposit = T::ParaDeposit::get()
@@ -557,12 +548,7 @@ mod tests {
 	}
 
 	fn test_validation_code(size: usize) -> ValidationCode {
-		let mut validation_code = vec![0u8; size as usize];
-		// Replace first bytes of code with "WASM_MAGIC" to pass validation test.
-		let _ = validation_code.splice(
-			..crate::WASM_MAGIC.len(),
-			crate::WASM_MAGIC.iter().cloned(),
-		).collect::<Vec<_>>();
+		let validation_code = vec![0u8; size as usize];
 		ValidationCode(validation_code)
 	}
 
@@ -811,7 +797,7 @@ mod tests {
 				Origin::signed(1),
 				1u32.into(),
 				vec![1; 3].into(),
-				WASM_MAGIC.to_vec().into(),
+				vec![1, 2, 3].into()
 			));
 
 			// 2 session changes to fully onboard.
@@ -827,7 +813,7 @@ mod tests {
 				Origin::signed(1),
 				1u32.into(),
 				vec![1; 3].into(),
-				WASM_MAGIC.to_vec().into(),
+				vec![1, 2, 3].into()
 			), Error::<Test>::AlreadyRegistered);
 
 			// By session 4, it is offboarded, and we can register again.
@@ -837,7 +823,7 @@ mod tests {
 				Origin::signed(1),
 				1u32.into(),
 				vec![1; 3].into(),
-				WASM_MAGIC.to_vec().into(),
+				vec![1, 2, 3].into()
 			));
 		});
 	}

polkadot/runtime/common/src/paras_sudo_wrapper.rs

@@ -16,7 +16,6 @@
 
 //! A simple wrapper allowing `Sudo` to call into `paras` routines.
 
-use crate::WASM_MAGIC;
 use sp_std::prelude::*;
 use frame_support::{
 	decl_error, decl_module, ensure,
@@ -47,8 +46,6 @@ decl_error! {
 		/// A DMP message couldn't be sent because it exceeds the maximum size allowed for a downward
 		/// message.
 		ExceedsMaxMessageSize,
-		/// The validation code provided doesn't start with the Wasm file magic string.
-		DefinitelyNotWasm,
 		/// Could not schedule para cleanup.
 		CouldntCleanup,
 		/// Not a parathread.
@@ -75,7 +72,6 @@ decl_module! {
 			genesis: ParaGenesisArgs,
 		) -> DispatchResult {
 			ensure_root(origin)?;
-			ensure!(genesis.validation_code.0.starts_with(WASM_MAGIC), Error::<T>::DefinitelyNotWasm);
 			runtime_parachains::schedule_para_initialize::<T>(id, genesis).map_err(|_| Error::<T>::ParaAlreadyExists)?;
 			Ok(())
 		}