referrerpolicy=no-referrer-when-downgrade
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
// This file is part of Substrate.

// Copyright (C) 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.

//! # Whitelist Pallet
//!
//! - [`Config`]
//! - [`Call`]
//!
//! ## Overview
//!
//! Allow some configurable origin: [`Config::WhitelistOrigin`] to whitelist some hash of a call,
//! and allow another configurable origin: [`Config::DispatchWhitelistedOrigin`] to dispatch them
//! with the root origin.
//!
//! In the meantime the call corresponding to the hash must have been submitted to the pre-image
//! handler [`pallet::Config::Preimages`].

#![cfg_attr(not(feature = "std"), no_std)]

#[cfg(feature = "runtime-benchmarks")]
mod benchmarking;
#[cfg(test)]
mod mock;
#[cfg(test)]
mod tests;
pub mod weights;
pub use weights::WeightInfo;

extern crate alloc;

use alloc::boxed::Box;
use codec::{DecodeLimit, Encode, FullCodec};
use frame_support::{
	dispatch::{GetDispatchInfo, PostDispatchInfo},
	ensure,
	traits::{QueryPreimage, StorePreimage},
	weights::Weight,
};
use scale_info::TypeInfo;
use sp_runtime::traits::{Dispatchable, Hash};

pub use pallet::*;

#[frame_support::pallet]
pub mod pallet {
	use super::*;
	use frame_support::pallet_prelude::*;
	use frame_system::pallet_prelude::*;

	#[pallet::config]
	pub trait Config: frame_system::Config {
		/// The overarching event type.
		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;

		/// The overarching call type.
		type RuntimeCall: IsType<<Self as frame_system::Config>::RuntimeCall>
			+ Dispatchable<RuntimeOrigin = Self::RuntimeOrigin, PostInfo = PostDispatchInfo>
			+ GetDispatchInfo
			+ FullCodec
			+ TypeInfo
			+ From<frame_system::Call<Self>>
			+ Parameter;

		/// Required origin for whitelisting a call.
		type WhitelistOrigin: EnsureOrigin<Self::RuntimeOrigin>;

		/// Required origin for dispatching whitelisted call with root origin.
		type DispatchWhitelistedOrigin: EnsureOrigin<Self::RuntimeOrigin>;

		/// The handler of pre-images.
		type Preimages: QueryPreimage<H = Self::Hashing> + StorePreimage;

		/// The weight information for this pallet.
		type WeightInfo: WeightInfo;
	}

	#[pallet::pallet]
	pub struct Pallet<T>(_);

	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config> {
		CallWhitelisted { call_hash: T::Hash },
		WhitelistedCallRemoved { call_hash: T::Hash },
		WhitelistedCallDispatched { call_hash: T::Hash, result: DispatchResultWithPostInfo },
	}

	#[pallet::error]
	pub enum Error<T> {
		/// The preimage of the call hash could not be loaded.
		UnavailablePreImage,
		/// The call could not be decoded.
		UndecodableCall,
		/// The weight of the decoded call was higher than the witness.
		InvalidCallWeightWitness,
		/// The call was not whitelisted.
		CallIsNotWhitelisted,
		/// The call was already whitelisted; No-Op.
		CallAlreadyWhitelisted,
	}

	#[pallet::storage]
	pub type WhitelistedCall<T: Config> = StorageMap<_, Twox64Concat, T::Hash, (), OptionQuery>;

	#[pallet::call]
	impl<T: Config> Pallet<T> {
		#[pallet::call_index(0)]
		#[pallet::weight(T::WeightInfo::whitelist_call())]
		pub fn whitelist_call(origin: OriginFor<T>, call_hash: T::Hash) -> DispatchResult {
			T::WhitelistOrigin::ensure_origin(origin)?;

			ensure!(
				!WhitelistedCall::<T>::contains_key(call_hash),
				Error::<T>::CallAlreadyWhitelisted,
			);

			WhitelistedCall::<T>::insert(call_hash, ());
			T::Preimages::request(&call_hash);

			Self::deposit_event(Event::<T>::CallWhitelisted { call_hash });

			Ok(())
		}

		#[pallet::call_index(1)]
		#[pallet::weight(T::WeightInfo::remove_whitelisted_call())]
		pub fn remove_whitelisted_call(origin: OriginFor<T>, call_hash: T::Hash) -> DispatchResult {
			T::WhitelistOrigin::ensure_origin(origin)?;

			WhitelistedCall::<T>::take(call_hash).ok_or(Error::<T>::CallIsNotWhitelisted)?;

			T::Preimages::unrequest(&call_hash);

			Self::deposit_event(Event::<T>::WhitelistedCallRemoved { call_hash });

			Ok(())
		}

		#[pallet::call_index(2)]
		#[pallet::weight(
			T::WeightInfo::dispatch_whitelisted_call(*call_encoded_len)
				.saturating_add(*call_weight_witness)
		)]
		pub fn dispatch_whitelisted_call(
			origin: OriginFor<T>,
			call_hash: T::Hash,
			call_encoded_len: u32,
			call_weight_witness: Weight,
		) -> DispatchResultWithPostInfo {
			T::DispatchWhitelistedOrigin::ensure_origin(origin)?;

			ensure!(
				WhitelistedCall::<T>::contains_key(call_hash),
				Error::<T>::CallIsNotWhitelisted,
			);

			let call = T::Preimages::fetch(&call_hash, Some(call_encoded_len))
				.map_err(|_| Error::<T>::UnavailablePreImage)?;

			let call = <T as Config>::RuntimeCall::decode_all_with_depth_limit(
				sp_api::MAX_EXTRINSIC_DEPTH,
				&mut &call[..],
			)
			.map_err(|_| Error::<T>::UndecodableCall)?;

			ensure!(
				call.get_dispatch_info().call_weight.all_lte(call_weight_witness),
				Error::<T>::InvalidCallWeightWitness
			);

			let actual_weight = Self::clean_and_dispatch(call_hash, call).map(|w| {
				w.saturating_add(T::WeightInfo::dispatch_whitelisted_call(call_encoded_len))
			});

			Ok(actual_weight.into())
		}

		#[pallet::call_index(3)]
		#[pallet::weight({
			let call_weight = call.get_dispatch_info().call_weight;
			let call_len = call.encoded_size() as u32;

			T::WeightInfo::dispatch_whitelisted_call_with_preimage(call_len)
				.saturating_add(call_weight)
		})]
		pub fn dispatch_whitelisted_call_with_preimage(
			origin: OriginFor<T>,
			call: Box<<T as Config>::RuntimeCall>,
		) -> DispatchResultWithPostInfo {
			T::DispatchWhitelistedOrigin::ensure_origin(origin)?;

			let call_hash = T::Hashing::hash_of(&call).into();

			ensure!(
				WhitelistedCall::<T>::contains_key(call_hash),
				Error::<T>::CallIsNotWhitelisted,
			);

			let call_len = call.encoded_size() as u32;
			let actual_weight = Self::clean_and_dispatch(call_hash, *call).map(|w| {
				w.saturating_add(T::WeightInfo::dispatch_whitelisted_call_with_preimage(call_len))
			});

			Ok(actual_weight.into())
		}
	}
}

impl<T: Config> Pallet<T> {
	/// Clean whitelisting/preimage and dispatch call.
	///
	/// Return the call actual weight of the dispatched call if there is some.
	fn clean_and_dispatch(call_hash: T::Hash, call: <T as Config>::RuntimeCall) -> Option<Weight> {
		WhitelistedCall::<T>::remove(call_hash);

		T::Preimages::unrequest(&call_hash);

		let result = call.dispatch(frame_system::Origin::<T>::Root.into());

		let call_actual_weight = match result {
			Ok(call_post_info) => call_post_info.actual_weight,
			Err(call_err) => call_err.post_info.actual_weight,
		};

		Self::deposit_event(Event::<T>::WhitelistedCallDispatched { call_hash, result });

		call_actual_weight
	}
}