[XCM] allow signed account to be aliased between system chains

cumulus/parachains/common/src/xcm_config.rs

@@ -144,13 +144,44 @@ impl Contains<Location> for ParentRelayOrSiblingParachains {
 	}
 }
 
+/// Filter to check if a given `target` location represents the same AccountId32 as `origin`,
+/// but coming from another sibling system chain.
+///
+/// This type should only be used within the context of a parachain, to allow accounts on system
+/// chains to Alias to the same accounts on the local chain.
+pub struct AliasAccountId32FromSiblingSystemChain;
+impl ContainsPair<Location, Location> for AliasAccountId32FromSiblingSystemChain {
+	fn contains(origin: &Location, target: &Location) -> bool {
+		let result = match origin.unpack() {
+			// `origin` is AccountId32 on sibling system parachain
+			(1, [Parachain(para_id), AccountId32 { network: _, id: origin }])
+				if ParaId::from(*para_id).is_system() =>
+			{
+				match target.unpack() {
+					// `target` is local AccountId32 and matches `origin` remote account
+					(0, [AccountId32 { network: _, id: target }]) => target.eq(origin),
+					_ => false,
+				}
+			},
+			_ => false,
+		};
+		log::trace!(
+			target: "xcm::contains",
+			"AliasAccountId32FromSiblingSystemChain origin: {:?}, target: {:?}, result {:?}",
+			origin, target, result,
+		);
+		result
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use frame_support::{parameter_types, traits::Contains};
 
 	use super::{
-		AllSiblingSystemParachains, Asset, ConcreteAssetFromSystem, ContainsPair, GeneralIndex,
-		Here, Location, PalletInstance, Parachain, Parent,
+		AliasAccountId32FromSiblingSystemChain, AllSiblingSystemParachains, Asset,
+		ConcreteAssetFromSystem, ContainsPair, GeneralIndex, Here, Location, PalletInstance,
+		Parachain, Parent,
 	};
 	use polkadot_primitives::LOWEST_PUBLIC_ID;
 	use xcm::latest::prelude::*;
@@ -221,4 +252,54 @@ mod tests {
 		// when used with non-parachain
 		assert!(!AllSiblingSystemParachains::contains(&Location::new(1, [OnlyChild])));
 	}
+
+	#[test]
+	fn alias_accountid32_from_sibling_system_parachains() {
+		let acc_42 = AccountId32 { network: None, id: [42u8; 32] };
+		let acc_13 = AccountId32 { network: None, id: [13u8; 32] };
+		// origin acc_42 on sibling system parachain aliases into local acc_42
+		assert!(AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_42]),
+			&Location::new(0, [acc_42])
+		));
+		// if target is not local account, always fails
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_42]),
+			&Location::new(0, [])
+		));
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_42]),
+			&Location::new(0, [Parachain(1)])
+		));
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_42]),
+			&Location::new(0, [GeneralIndex(42)])
+		));
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_42]),
+			&Location::new(1, [acc_42])
+		));
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_42]),
+			&Location::new(2, [acc_42])
+		));
+		// origin acc_13 on sibling system parachain CANNOT alias into local acc_42
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(1), acc_13]),
+			&Location::new(0, [acc_42])
+		));
+		// origin acc_42 on sibling non-system parachain CANNOT alias into local acc_42
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(1, [Parachain(LOWEST_PUBLIC_ID.into()), acc_42]),
+			&Location::new(0, [acc_42])
+		));
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(0, [acc_13]),
+			&Location::new(0, [acc_13]),
+		));
+		assert!(!AliasAccountId32FromSiblingSystemChain::contains(
+			&Location::new(0, [acc_42]),
+			&Location::new(1, [Parachain(1), acc_42]),
+		));
+	}
 }

cumulus/parachains/integration-tests/emulated/common/src/macros.rs

@@ -745,3 +745,80 @@ macro_rules! test_xcm_fee_querying_apis_work_for_asset_hub {
 		}
 	};
 }
+
+#[macro_export]
+macro_rules! test_cross_chain_alias {
+	( vec![$( ($sender_para:ty, $receiver_para:ty, $is_teleport:expr, $expected_success:expr) ),+], $origin:expr, $target:expr, $fees:expr ) => {
+		$crate::macros::paste::paste! {
+			use xcm::latest::AssetTransferFilter;
+			$(
+				{
+					let para_destination = <$sender_para>::sibling_location_of(<$receiver_para>::para_id());
+					let account: AccountId = $origin.clone().into();
+					$sender_para::fund_accounts(vec![(account.clone(), $fees * 10)]);
+					let total_fees: Asset = (Location::parent(), $fees).into();
+					let fees: Asset = (Location::parent(), $fees / 2).into();
+
+					let remote_fees = if $is_teleport {
+						Some(AssetTransferFilter::Teleport(fees.clone().into()))
+					} else {
+						let source_para_sa = <$receiver_para>::sovereign_account_id_of(
+							<$receiver_para>::sibling_location_of(<$sender_para>::para_id()),
+						);
+						$receiver_para::fund_accounts(vec![(source_para_sa, $fees * 10)]);
+						Some(AssetTransferFilter::ReserveWithdraw(fees.clone().into()))
+					};
+					<$sender_para>::execute_with(|| {
+						type RuntimeEvent = <$sender_para as $crate::macros::Chain>::RuntimeEvent;
+						let xcm_message = Xcm::<()>(vec![
+							WithdrawAsset(total_fees.into()),
+							PayFees { asset: fees.clone() },
+							InitiateTransfer {
+								destination: para_destination,
+								remote_fees,
+								preserve_origin: true,
+								assets: BoundedVec::new(),
+								remote_xcm: Xcm(vec![
+									// try to alias into `account`
+									AliasOrigin($target.clone().into()),
+									RefundSurplus,
+									DepositAsset {
+										assets: Wild(AllCounted(1)),
+										beneficiary: $target.clone().into(),
+									},
+								]),
+							},
+							RefundSurplus,
+							DepositAsset { assets: Wild(AllCounted(1)), beneficiary: account.clone().into() },
+						]);
+
+						let signed_origin = <$sender_para as Chain>::RuntimeOrigin::signed(account.into());
+						assert_ok!(<$sender_para as [<$sender_para Pallet>]>::PolkadotXcm::execute(
+							signed_origin,
+							bx!(xcm::VersionedXcm::from(xcm_message.into())),
+							Weight::MAX
+						));
+						assert_expected_events!(
+							$sender_para,
+							vec![
+								RuntimeEvent::PolkadotXcm(pallet_xcm::Event::Sent { .. }) => {},
+							]
+						);
+					});
+
+					<$receiver_para>::execute_with(|| {
+						type RuntimeEvent = <$receiver_para as $crate::macros::Chain>::RuntimeEvent;
+						assert_expected_events!(
+							$receiver_para,
+							vec![
+								RuntimeEvent::MessageQueue(pallet_message_queue::Event::Processed {
+									success, ..
+								}) => { success: *success == $expected_success, },
+							]
+						);
+					});
+				}
+			)+
+		}
+	};
+}

cumulus/parachains/integration-tests/emulated/tests/assets/asset-hub-westend/src/lib.rs

@@ -63,10 +63,12 @@ mod imports {
 			genesis::{AssetHubWestendAssetOwner, ED as ASSET_HUB_WESTEND_ED},
 			AssetHubWestendParaPallet as AssetHubWestendPallet,
 		},
-		bridge_hub_westend_emulated_chain::bridge_hub_westend_runtime::xcm_config::{
-			self as bhw_xcm_config,
+		bridge_hub_westend_emulated_chain::{
+			bridge_hub_westend_runtime::xcm_config::{self as bhw_xcm_config},
+			BridgeHubWestendParaPallet as BridgeHubWestendPallet,
 		},
 		collectives_westend_emulated_chain::CollectivesWestendParaPallet as CollectivesWestendPallet,
+		coretime_westend_emulated_chain::CoretimeWestendParaPallet as CoretimeWestendPallet,
 		penpal_emulated_chain::{
 			penpal_runtime::xcm_config::{
 				CustomizableAssetFromSystemAssetHub as PenpalCustomizableAssetFromSystemAssetHub,
@@ -78,6 +80,7 @@ mod imports {
 			PenpalAParaPallet as PenpalAPallet, PenpalAssetOwner,
 			PenpalBParaPallet as PenpalBPallet,
 		},
+		people_westend_emulated_chain::PeopleWestendParaPallet as PeopleWestendPallet,
 		westend_emulated_chain::{
 			genesis::ED as WESTEND_ED,
 			westend_runtime::{
@@ -94,10 +97,12 @@ mod imports {
 		AssetHubWestendParaSender as AssetHubWestendSender,
 		BridgeHubWestendPara as BridgeHubWestend,
 		BridgeHubWestendParaReceiver as BridgeHubWestendReceiver,
-		CollectivesWestendPara as CollectivesWestend, PenpalAPara as PenpalA,
-		PenpalAParaReceiver as PenpalAReceiver, PenpalAParaSender as PenpalASender,
-		PenpalBPara as PenpalB, PenpalBParaReceiver as PenpalBReceiver, WestendRelay as Westend,
-		WestendRelayReceiver as WestendReceiver, WestendRelaySender as WestendSender,
+		CollectivesWestendPara as CollectivesWestend, CoretimeWestendPara as CoretimeWestend,
+		PenpalAPara as PenpalA, PenpalAParaReceiver as PenpalAReceiver,
+		PenpalAParaSender as PenpalASender, PenpalBPara as PenpalB,
+		PenpalBParaReceiver as PenpalBReceiver, PeopleWestendPara as PeopleWestend,
+		WestendRelay as Westend, WestendRelayReceiver as WestendReceiver,
+		WestendRelaySender as WestendSender,
 	};
 
 	pub const ASSET_ID: u32 = 3;