Introduce CheckNonZeroSender (#10413)

* Introduce CheckNonZeroSender

* Missing file

* Formatting

* Fixes

* Formatting

* some fixes to compile

* Update frame/system/src/extensions/check_non_zero_sender.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Fixes

* Fixes

* another fix

* Formatting

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/frame/system/src/extensions/check_non_zero_sender.rs

@@ -0,0 +1,100 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::Config;
+use codec::{Decode, Encode};
+use frame_support::weights::DispatchInfo;
+use scale_info::TypeInfo;
+use sp_runtime::{
+	traits::{DispatchInfoOf, Dispatchable, SignedExtension},
+	transaction_validity::{
+		InvalidTransaction, TransactionValidity, TransactionValidityError, ValidTransaction,
+	},
+};
+use sp_std::{marker::PhantomData, prelude::*};
+
+/// Check to ensure that the sender is not the zero address.
+#[derive(Encode, Decode, Clone, Eq, PartialEq, TypeInfo)]
+#[scale_info(skip_type_params(T))]
+pub struct CheckNonZeroSender<T: Config + Send + Sync>(PhantomData<T>);
+
+impl<T: Config + Send + Sync> sp_std::fmt::Debug for CheckNonZeroSender<T> {
+	#[cfg(feature = "std")]
+	fn fmt(&self, f: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
+		write!(f, "CheckNonZeroSender")
+	}
+
+	#[cfg(not(feature = "std"))]
+	fn fmt(&self, _: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
+		Ok(())
+	}
+}
+
+impl<T: Config + Send + Sync> CheckNonZeroSender<T> {
+	/// Create new `SignedExtension` to check runtime version.
+	pub fn new() -> Self {
+		Self(sp_std::marker::PhantomData)
+	}
+}
+
+impl<T: Config + Send + Sync> SignedExtension for CheckNonZeroSender<T>
+where
+	T::Call: Dispatchable<Info = DispatchInfo>,
+{
+	type AccountId = T::AccountId;
+	type Call = T::Call;
+	type AdditionalSigned = ();
+	type Pre = ();
+	const IDENTIFIER: &'static str = "CheckNonZeroSender";
+
+	fn additional_signed(&self) -> sp_std::result::Result<(), TransactionValidityError> {
+		Ok(())
+	}
+
+	fn validate(
+		&self,
+		who: &Self::AccountId,
+		_call: &Self::Call,
+		_info: &DispatchInfoOf<Self::Call>,
+		_len: usize,
+	) -> TransactionValidity {
+		if who.using_encoded(|d| d.into_iter().all(|x| *x == 0)) {
+			return Err(TransactionValidityError::Invalid(InvalidTransaction::BadSigner))
+		}
+		Ok(ValidTransaction::default())
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::mock::{new_test_ext, Test, CALL};
+	use frame_support::{assert_noop, assert_ok};
+
+	#[test]
+	fn zero_account_ban_works() {
+		new_test_ext().execute_with(|| {
+			let info = DispatchInfo::default();
+			let len = 0_usize;
+			assert_noop!(
+				CheckNonZeroSender::<Test>::new().validate(&0, CALL, &info, len),
+				InvalidTransaction::BadSigner
+			);
+			assert_ok!(CheckNonZeroSender::<Test>::new().validate(&1, CALL, &info, len));
+		})
+	}
+}

substrate/frame/system/src/extensions/mod.rs

@@ -17,6 +17,7 @@
 
 pub mod check_genesis;
 pub mod check_mortality;
+pub mod check_non_zero_sender;
 pub mod check_nonce;
 pub mod check_spec_version;
 pub mod check_tx_version;

substrate/frame/system/src/lib.rs

@@ -115,7 +115,8 @@ mod tests;
 pub mod weights;
 
 pub use extensions::{
-	check_genesis::CheckGenesis, check_mortality::CheckMortality, check_nonce::CheckNonce,
+	check_genesis::CheckGenesis, check_mortality::CheckMortality,
+	check_non_zero_sender::CheckNonZeroSender, check_nonce::CheckNonce,
 	check_spec_version::CheckSpecVersion, check_tx_version::CheckTxVersion,
 	check_weight::CheckWeight,
 };