Introduce Tinkernet multisig XCM configs to Kusama/Rococo through xcm-builder

runtime/kusama/src/xcm_config.rs

@@ -41,8 +41,9 @@ use xcm_builder::{
 	ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
 	CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds, IsChildSystemParachain, IsConcrete,
 	MintLocation, OriginToPluralityVoice, SignedAccountId32AsNative, SignedToAccountId32,
-	SovereignSignedViaLocation, TakeWeightCredit, TrailingSetTopicAsId, UsingComponents,
-	WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
+	SovereignSignedViaLocation, TakeWeightCredit, TinkernetMultisigAsAccountId,
+	TinkernetMultisigAsNative, TrailingSetTopicAsId, UsingComponents, WeightInfoBounds,
+	WithComputedOrigin, WithUniqueTopic,
 };
 use xcm_executor::traits::WithOriginFilter;
 
@@ -70,6 +71,8 @@ pub type SovereignAccountOf = (
 	ChildParachainConvertsVia<ParaId, AccountId>,
 	// We can directly alias an `AccountId32` into a local account.
 	AccountId32Aliases<ThisNetwork, AccountId>,
+	// We can derive a local account from a Tinkernet XCMultisig MultiLocation.
+	TinkernetMultisigAsAccountId<AccountId>,
 );
 
 /// Our asset transactor. This is what allows us to interest with the runtime facilities from the point of
@@ -99,6 +102,8 @@ type LocalOriginConverter = (
 	SignedAccountId32AsNative<ThisNetwork, RuntimeOrigin>,
 	// A system child parachain, expressed as a Superuser, converts to the `Root` origin.
 	ChildSystemParachainAsSuperuser<ParaId, RuntimeOrigin>,
+	// Converts a Tinkernet XCMultisig MultiLocation into a `Signed` origin.
+	TinkernetMultisigAsNative<RuntimeOrigin>,
 );
 
 parameter_types! {

runtime/rococo/src/xcm_config.rs

@@ -40,8 +40,8 @@ use xcm_builder::{
 	ChildParachainAsNative, ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
 	CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds, IsChildSystemParachain, IsConcrete,
 	MintLocation, SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation,
-	TakeWeightCredit, TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin,
-	WithUniqueTopic,
+	TakeWeightCredit, TinkernetMultisigAsAccountId, TinkernetMultisigAsNative,
+	TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
 };
 use xcm_executor::{traits::WithOriginFilter, XcmExecutor};
 
@@ -53,8 +53,12 @@ parameter_types! {
 	pub LocalCheckAccount: (AccountId, MintLocation) = (CheckAccount::get(), MintLocation::Local);
 }
 
-pub type LocationConverter =
-	(ChildParachainConvertsVia<ParaId, AccountId>, AccountId32Aliases<ThisNetwork, AccountId>);
+pub type LocationConverter = (
+	ChildParachainConvertsVia<ParaId, AccountId>,
+	AccountId32Aliases<ThisNetwork, AccountId>,
+	// We can derive a local account from a Tinkernet XCMultisig MultiLocation.
+	TinkernetMultisigAsAccountId<AccountId>,
+);
 
 /// Our asset transactor. This is what allows us to interest with the runtime facilities from the point of
 /// view of XCM-only concepts like `MultiLocation` and `MultiAsset`.
@@ -83,6 +87,8 @@ type LocalOriginConverter = (
 	SignedAccountId32AsNative<ThisNetwork, RuntimeOrigin>,
 	// A system child parachain, expressed as a Superuser, converts to the `Root` origin.
 	ChildSystemParachainAsSuperuser<ParaId, RuntimeOrigin>,
+	// Converts a Tinkernet XCMultisig MultiLocation into a `Signed` origin.
+	TinkernetMultisigAsNative<RuntimeOrigin>,
 );
 
 parameter_types! {

xcm/xcm-builder/Cargo.toml

@@ -15,6 +15,7 @@ sp-std = { git = "https://github.com/paritytech/substrate", branch = "master", d
 sp-arithmetic = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-io = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-weights = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 frame-support = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 frame-system = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
@@ -49,6 +50,7 @@ std = [
 	"sp-arithmetic/std",
 	"sp-io/std",
 	"sp-runtime/std",
+	"sp-core/std",
 	"sp-weights/std",
 	"frame-support/std",
 	"frame-system/std",

xcm/xcm-builder/src/lib.rs

@@ -34,15 +34,15 @@ pub use location_conversion::{
 	ChildParachainConvertsVia, DescribeAccountId32Terminal, DescribeAccountIdTerminal,
 	DescribeAccountKey20Terminal, DescribeAllTerminal, DescribeFamily, DescribeLocation,
 	DescribePalletTerminal, DescribeTerminus, GlobalConsensusParachainConvertsFor,
-	HashedDescription, ParentIsPreset, SiblingParachainConvertsVia,
+	HashedDescription, ParentIsPreset, SiblingParachainConvertsVia, TinkernetMultisigAsAccountId,
 };
 
 mod origin_conversion;
 pub use origin_conversion::{
 	BackingToPlurality, ChildParachainAsNative, ChildSystemParachainAsSuperuser, EnsureXcmOrigin,
 	OriginToPluralityVoice, ParentAsSuperuser, RelayChainAsNative, SiblingParachainAsNative,
 	SiblingSystemParachainAsSuperuser, SignedAccountId32AsNative, SignedAccountKey20AsNative,
-	SignedToAccountId32, SovereignSignedViaLocation,
+	SignedToAccountId32, SovereignSignedViaLocation, TinkernetMultisigAsNative,
 };
 
 mod asset_conversion;

xcm/xcm-builder/src/location_conversion.rs

@@ -17,6 +17,7 @@
 use crate::universal_exports::ensure_is_remote;
 use frame_support::traits::Get;
 use parity_scale_codec::{Compact, Decode, Encode};
+use sp_core::H256;
 use sp_io::hashing::blake2_256;
 use sp_runtime::traits::{AccountIdConversion, Convert, TrailingZeroInput};
 use sp_std::{marker::PhantomData, prelude::*};
@@ -345,6 +346,52 @@ impl<Network: Get<Option<NetworkId>>, AccountId: From<[u8; 20]> + Into<[u8; 20]>
 	}
 }
 
+/// Tinkernet ParaId used when matching Multisig MultiLocations.
+pub const KUSAMA_TINKERNET_PARA_ID: u32 = 2125;
+
+/// Tinkernet Multisig pallet instance used when matching Multisig MultiLocations.
+pub const KUSAMA_TINKERNET_MULTISIG_PALLET: u8 = 71;
+
+/// Constant derivation function for Tinkernet Multisigs.
+/// Uses the Tinkernet genesis hash as a salt.
+pub fn derive_tinkernet_multisig<AccountId: Decode>(id: u128) -> Result<AccountId, ()> {
+	AccountId::decode(&mut TrailingZeroInput::new(
+		&(
+			// The constant salt used to derive Tinkernet Multisigs, this is Tinkernet's genesis hash.
+			H256([
+				212, 46, 150, 6, 169, 149, 223, 228, 51, 220, 121, 85, 220, 42, 112, 244, 149, 243,
+				80, 243, 115, 218, 162, 0, 9, 138, 232, 68, 55, 129, 106, 210,
+			]),
+			// The actual multisig integer id.
+			u32::try_from(id).map_err(|_| ())?,
+		)
+			.using_encoded(blake2_256),
+	))
+	.map_err(|_| ())
+}
+
+/// Convert a Tinkernet Multisig `MultiLocation` value into a local `AccountId`.
+pub struct TinkernetMultisigAsAccountId<AccountId>(PhantomData<AccountId>);
+impl<AccountId: Decode + Clone> ConvertLocation<AccountId>
+	for TinkernetMultisigAsAccountId<AccountId>
+{
+	fn convert_location(location: &MultiLocation) -> Option<AccountId> {
+		match location {
+			MultiLocation {
+				parents: _,
+				interior:
+					X3(
+						Parachain(KUSAMA_TINKERNET_PARA_ID),
+						PalletInstance(KUSAMA_TINKERNET_MULTISIG_PALLET),
+						// Index from which the multisig account is derived.
+						GeneralIndex(id),
+					),
+			} => derive_tinkernet_multisig(*id).ok(),
+			_ => None,
+		}
+	}
+}
+
 /// Converts a location which is a top-level parachain (i.e. a parachain held on a
 /// Relay-chain which provides its own consensus) into a 32-byte `AccountId`.
 ///
@@ -789,4 +836,24 @@ mod tests {
 		};
 		assert!(ForeignChainAliasAccount::<[u8; 32]>::convert_location(&mul).is_none());
 	}
+
+	#[test]
+	fn remote_tinkernet_multisig_convert_to_account() {
+		let mul = MultiLocation {
+			parents: 0,
+			interior: X3(
+				Parachain(KUSAMA_TINKERNET_PARA_ID),
+				PalletInstance(KUSAMA_TINKERNET_MULTISIG_PALLET),
+				GeneralIndex(0),
+			),
+		};
+
+		assert_eq!(
+			[
+				97, 160, 244, 60, 133, 145, 170, 26, 202, 108, 203, 156, 114, 116, 175, 30, 156,
+				195, 43, 101, 243, 51, 193, 162, 152, 188, 30, 165, 244, 81, 70, 90
+			],
+			TinkernetMultisigAsAccountId::<[u8; 32]>::convert_location(&mul).unwrap()
+		);
+	}
 }

xcm/xcm-builder/src/origin_conversion.rs

@@ -16,8 +16,12 @@
 
 //! Various implementations for `ConvertOrigin`.
 
+use crate::location_conversion::{
+	derive_tinkernet_multisig, KUSAMA_TINKERNET_MULTISIG_PALLET, KUSAMA_TINKERNET_PARA_ID,
+};
 use frame_support::traits::{EnsureOrigin, Get, GetBacking, OriginTrait};
 use frame_system::RawOrigin as SystemRawOrigin;
+use parity_scale_codec::Decode;
 use polkadot_parachain::primitives::IsSystem;
 use sp_runtime::traits::TryConvert;
 use sp_std::marker::PhantomData;
@@ -241,6 +245,37 @@ where
 	}
 }
 
+/// Convert a Tinkernet Multisig `MultiLocation` value into a `Signed` origin.
+pub struct TinkernetMultisigAsNative<RuntimeOrigin>(PhantomData<RuntimeOrigin>);
+impl<RuntimeOrigin: OriginTrait> ConvertOrigin<RuntimeOrigin>
+	for TinkernetMultisigAsNative<RuntimeOrigin>
+where
+	RuntimeOrigin::AccountId: Decode,
+{
+	fn convert_origin(
+		origin: impl Into<MultiLocation>,
+		kind: OriginKind,
+	) -> Result<RuntimeOrigin, MultiLocation> {
+		let origin = origin.into();
+		match (kind, origin) {
+			(
+				OriginKind::Native,
+				MultiLocation {
+					parents: _,
+					interior:
+						X3(
+							Junction::Parachain(KUSAMA_TINKERNET_PARA_ID),
+							Junction::PalletInstance(KUSAMA_TINKERNET_MULTISIG_PALLET),
+							// Index from which the multisig account is derived.
+							Junction::GeneralIndex(id),
+						),
+				},
+			) => Ok(RuntimeOrigin::signed(derive_tinkernet_multisig(id).map_err(|_| origin)?)),
+			(_, origin) => Err(origin),
+		}
+	}
+}
+
 /// `EnsureOrigin` barrier to convert from dispatch origin to XCM origin, if one exists.
 pub struct EnsureXcmOrigin<RuntimeOrigin, Conversion>(PhantomData<(RuntimeOrigin, Conversion)>);
 impl<RuntimeOrigin: OriginTrait + Clone, Conversion: TryConvert<RuntimeOrigin, MultiLocation>>