Harden XCM v1 for Recursions (#3586)

* Guard against XCM recursive bombs by setting a recursion limit

* Add test and set a lower recursion limit

* Use u32 instead of usize for recursion limit

* Make spellcheck happy

* Cargo fmt

* Limit XCM decoding depth in UMP message processing

* Modify test to check for recursion in BuyExecution

* Update xcm/xcm-simulator/example/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Make cargo fmt happy

* WIP for testing recursion limit in WASM

* Revert "WIP for testing recursion limit in WASM"

This reverts commit 39181b46d1adf79358f5ae8aafcf480e0c0c22e6.

* Remove XCM recursion limit test

* Add recursion test for XCM message execution

* Set a more sensible recursion limit

* Cargo fmt

* Implement successful_origin for benchmarks

* Set recursion limit to 8 and create integration tests directory for xcm-executor

* Cargo fmt

* Add runtime-benchmarks feature to test-runtime

* Give up creating ConvertOriginToLocal and use EnsureXcm

* Re-add ConvertOriginToLocal

* Fix compilation

* Update xcm/xcm-executor/src/lib.rs

Co-authored-by: Gavin Wood <gavin@parity.io>

* Add decoding limit to all versioned XCM decode calls

* Fix recursion limit test

* Set a lower recursion count for recursion test

* move integration tests to their own folder, fix recursion check in execute_effects

* Remove xcm-executor integration tests directory

* fix up

* Update Cargo.lock

* Update runtime/parachains/src/ump.rs

* use proper decode limit

* fix decode depth limit

* here too

* Update traits.rs

* fix compile

* fix test

* Revert `decode_all_with_depth_limit` changes in parachain.rs

* Remove unused imports in parachain.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: Bastian Köcher <info@kchr.de>
Co-authored-by: Gavin Wood <gavin@parity.io>

polkadot/runtime/test-runtime/src/lib.rs

@@ -79,6 +79,7 @@ pub use sp_runtime::BuildStorage;
 
 /// Constant values used within the runtime.
 pub mod constants;
+pub mod xcm_config;
 use constants::{currency::*, fee::*, time::*};
 
 // Make the WASM binary available.
@@ -488,6 +489,31 @@ impl parachains_ump::Config for Runtime {
 	type FirstMessageFactorPercent = FirstMessageFactorPercent;
 }
 
+parameter_types! {
+	pub const BaseXcmWeight: frame_support::weights::Weight = 1_000;
+	pub const AnyNetwork: xcm::latest::NetworkId = xcm::latest::NetworkId::Any;
+}
+
+pub type LocalOriginToLocation = xcm_builder::SignedToAccountId32<Origin, AccountId, AnyNetwork>;
+
+impl pallet_xcm::Config for Runtime {
+	// The config types here are entirely configurable, since the only one that is sorely needed
+	// is `XcmExecutor`, which will be used in unit tests located in xcm-executor.
+	type Event = Event;
+	type ExecuteXcmOrigin = xcm_builder::EnsureXcmOrigin<Origin, LocalOriginToLocation>;
+	type LocationInverter = xcm_config::InvertNothing;
+	type SendXcmOrigin = xcm_builder::EnsureXcmOrigin<Origin, LocalOriginToLocation>;
+	type Weigher = xcm_builder::FixedWeightBounds<BaseXcmWeight, Call>;
+	type XcmRouter = xcm_config::DoNothingRouter;
+	type XcmExecuteFilter =
+		frame_support::traits::All<(xcm::latest::MultiLocation, xcm::latest::Xcm<Call>)>;
+	type XcmExecutor = xcm_executor::XcmExecutor<xcm_config::XcmConfig>;
+	type XcmTeleportFilter =
+		frame_support::traits::All<(xcm::latest::MultiLocation, Vec<xcm::latest::MultiAsset>)>;
+	type XcmReserveTransferFilter =
+		frame_support::traits::All<(xcm::latest::MultiLocation, Vec<xcm::latest::MultiAsset>)>;
+}
+
 impl parachains_hrmp::Config for Runtime {
 	type Event = Event;
 	type Origin = Origin;
@@ -543,6 +569,7 @@ construct_runtime! {
 		Hrmp: parachains_hrmp::{Pallet, Call, Storage, Event<T>},
 		Ump: parachains_ump::{Pallet, Call, Storage, Event},
 		Dmp: parachains_dmp::{Pallet, Call, Storage},
+		Xcm: pallet_xcm::{Pallet, Call, Event<T>, Origin},
 		ParasDisputes: parachains_disputes::{Pallet, Storage, Event<T>},
 
 		Sudo: pallet_sudo::{Pallet, Call, Storage, Config<T>, Event<T>},

polkadot/runtime/test-runtime/src/xcm_config.rs

@@ -0,0 +1,91 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+use frame_support::{parameter_types, traits::All, weights::Weight};
+use xcm::latest::{
+	Error as XcmError, Junction::*, MultiAsset, MultiLocation, MultiLocation::*, NetworkId,
+	Result as XcmResult, SendXcm, Xcm,
+};
+use xcm_builder::{AllowUnpaidExecutionFrom, FixedWeightBounds, SignedToAccountId32};
+use xcm_executor::{
+	traits::{InvertLocation, TransactAsset, WeightTrader},
+	Assets,
+};
+
+parameter_types! {
+	pub const OurNetwork: NetworkId = NetworkId::Polkadot;
+}
+
+/// Type to convert an `Origin` type value into a `MultiLocation` value which represents an interior location
+/// of this chain.
+pub type LocalOriginToLocation = (
+	// And a usual Signed origin to be used in XCM as a corresponding AccountId32
+	SignedToAccountId32<crate::Origin, crate::AccountId, OurNetwork>,
+);
+
+pub struct DoNothingRouter;
+impl SendXcm for DoNothingRouter {
+	fn send_xcm(_dest: MultiLocation, _msg: Xcm<()>) -> XcmResult {
+		Ok(())
+	}
+}
+
+pub type Barrier = AllowUnpaidExecutionFrom<All<MultiLocation>>;
+
+pub struct DummyAssetTransactor;
+impl TransactAsset for DummyAssetTransactor {
+	fn deposit_asset(_what: &MultiAsset, _who: &MultiLocation) -> XcmResult {
+		Ok(())
+	}
+
+	fn withdraw_asset(_what: &MultiAsset, _who: &MultiLocation) -> Result<Assets, XcmError> {
+		let asset: MultiAsset = (X1(Parent), 100_000).into();
+		Ok(asset.into())
+	}
+}
+
+pub struct DummyWeightTrader;
+impl WeightTrader for DummyWeightTrader {
+	fn new() -> Self {
+		DummyWeightTrader
+	}
+
+	fn buy_weight(&mut self, _weight: Weight, _payment: Assets) -> Result<Assets, XcmError> {
+		Ok(Assets::default())
+	}
+}
+
+pub struct InvertNothing;
+impl InvertLocation for InvertNothing {
+	fn invert_location(_: &MultiLocation) -> MultiLocation {
+		MultiLocation::Here
+	}
+}
+
+pub struct XcmConfig;
+impl xcm_executor::Config for XcmConfig {
+	type Call = super::Call;
+	type XcmSender = DoNothingRouter;
+	type AssetTransactor = DummyAssetTransactor;
+	type OriginConverter = pallet_xcm::XcmPassthrough<super::Origin>;
+	type IsReserve = ();
+	type IsTeleporter = ();
+	type LocationInverter = InvertNothing;
+	type Barrier = Barrier;
+	type Weigher = FixedWeightBounds<super::BaseXcmWeight, super::Call>;
+	type Trader = DummyWeightTrader;
+	type ResponseHandler = ();
+}