Restrict governance messages to governance channel id (#786)

* Restrict governance messages to governance channel id

* Fix tests and add tests

* Unused variable

primitives/bridge/src/symbiotic_message_processor.rs

@@ -16,7 +16,7 @@
 
 use frame_support::pallet_prelude::*;
 use parity_scale_codec::DecodeAll;
-use snowbridge_core::Channel;
+use snowbridge_core::{Channel, PRIMARY_GOVERNANCE_CHANNEL};
 use snowbridge_router_primitives::inbound::envelope::Envelope;
 use snowbridge_router_primitives::inbound::MessageProcessor;
 use sp_runtime::DispatchError;
@@ -84,6 +84,11 @@ where
 
         match message {
             Message::V1(InboundCommand::ReceiveValidators { validators }) => {
+                if envelope.channel_id != PRIMARY_GOVERNANCE_CHANNEL {
+                    return Err(DispatchError::Other(
+                        "Received governance message from invalid channel id",
+                    ));
+                }
                 pallet_external_validators::Pallet::<T>::set_external_validators(validators)?;
                 Ok(())
             }

solo-chains/runtime/dancelight/src/tests/inbound_queue_tests/integration_tests.rs

@@ -24,7 +24,7 @@ use snowbridge_beacon_primitives::types::deneb;
 use snowbridge_beacon_primitives::{ExecutionProof, VersionedExecutionPayloadHeader};
 use snowbridge_core::{
     inbound::{Log, Message, Proof},
-    Channel, ChannelId,
+    Channel, PRIMARY_GOVERNANCE_CHANNEL,
 };
 use snowbridge_router_primitives::inbound::envelope::OutboundMessageAccepted;
 use sp_core::H256;
@@ -33,14 +33,12 @@ use tp_bridge::symbiotic_message_processor::{
     InboundCommand, Message as SymbioticMessage, Payload, MAGIC_BYTES,
 };
 
-const MOCK_CHANNEL_ID: [u8; 32] = [0; 32];
-
 #[test]
 fn test_inbound_queue_message_passing() {
     ExtBuilder::default().build().execute_with(|| {
         let current_nonce = 1;
 
-        snowbridge_pallet_system::Channels::<Runtime>::set(ChannelId::from(MOCK_CHANNEL_ID), Some(Channel {
+        snowbridge_pallet_system::Channels::<Runtime>::set(PRIMARY_GOVERNANCE_CHANNEL, Some(Channel {
             agent_id: Default::default(),
             para_id: Default::default()
         }));
@@ -71,7 +69,7 @@ fn test_inbound_queue_message_passing() {
         } };
 
         let event_with_empty_payload = OutboundMessageAccepted {
-            channel_id: MOCK_CHANNEL_ID.into(),
+            channel_id: <[u8; 32]>::from(PRIMARY_GOVERNANCE_CHANNEL).into(),
             nonce: current_nonce,
             message_id: Default::default(),
             payload: vec![],
@@ -102,7 +100,7 @@ fn test_inbound_queue_message_passing() {
         };
 
         let event_with_valid_payload = OutboundMessageAccepted {
-            channel_id: MOCK_CHANNEL_ID.into(),
+            channel_id: <[u8; 32]>::from(PRIMARY_GOVERNANCE_CHANNEL).into(),
             nonce: current_nonce,
             message_id: Default::default(),
             payload: payload.encode(),

solo-chains/runtime/dancelight/src/tests/inbound_queue_tests/message_processor_tests.rs

@@ -18,7 +18,7 @@ use crate::tests::common::ExtBuilder;
 use crate::{ExternalValidators, Runtime};
 use frame_support::pallet_prelude::*;
 use keyring::AccountKeyring;
-use snowbridge_core::Channel;
+use snowbridge_core::{Channel, PRIMARY_GOVERNANCE_CHANNEL};
 use snowbridge_router_primitives::inbound::envelope::Envelope;
 use snowbridge_router_primitives::inbound::MessageProcessor;
 use sp_core::{H160, H256};
@@ -36,7 +36,7 @@ fn test_symbiotic_message_processor() {
         };
 
         let envelope_with_invalid_payload = Envelope {
-            channel_id: H256::default().into(),
+            channel_id: PRIMARY_GOVERNANCE_CHANNEL,
             gateway: H160::default(),
             message_id: Default::default(),
             nonce: 0,
@@ -65,7 +65,7 @@ fn test_symbiotic_message_processor() {
             }),
         };
         let envelope = Envelope {
-            channel_id: H256::default().into(),
+            channel_id: PRIMARY_GOVERNANCE_CHANNEL,
             gateway: H160::default(),
             message_id: Default::default(),
             nonce: 0,
@@ -95,7 +95,7 @@ fn test_symbiotic_message_processor() {
             }),
         };
         let envelope = Envelope {
-            channel_id: H256::default().into(),
+            channel_id: PRIMARY_GOVERNANCE_CHANNEL,
             gateway: H160::default(),
             message_id: Default::default(),
             nonce: 0,
@@ -121,3 +121,55 @@ fn test_symbiotic_message_processor() {
         assert_eq!(ExternalValidators::validators(), expected_validators);
     });
 }
+
+#[test]
+fn test_symbiotic_message_processor_rejects_invalid_channel_id() {
+    ExtBuilder::default().build().execute_with(|| {
+        let default_channel = Channel {
+            agent_id: H256::default(),
+            para_id: 0.into(),
+        };
+
+        // No external validators are set right now
+        assert_eq!(
+            ExternalValidators::validators(),
+            ExternalValidators::whitelisted_validators()
+        );
+
+        let payload_validators = vec![
+            AccountKeyring::Alice.to_account_id(),
+            AccountKeyring::Charlie.to_account_id(),
+            AccountKeyring::Bob.to_account_id(),
+        ];
+
+        let payload_with_correct_magic_bytes = Payload {
+            magic_bytes: MAGIC_BYTES,
+            message: Message::V1(InboundCommand::<Runtime>::ReceiveValidators {
+                validators: payload_validators.clone(),
+            }),
+        };
+        let envelope = Envelope {
+            channel_id: H256::default().into(),
+            gateway: H160::default(),
+            message_id: Default::default(),
+            nonce: 0,
+            payload: payload_with_correct_magic_bytes.encode(),
+        };
+        assert_eq!(
+            SymbioticMessageProcessor::<Runtime>::can_process_message(&default_channel, &envelope),
+            true
+        );
+        assert_eq!(
+            SymbioticMessageProcessor::<Runtime>::process_message(
+                default_channel.clone(),
+                envelope
+            ),
+            Err(DispatchError::Other(
+                "Received governance message from invalid channel id"
+            ))
+        );
+
+        let expected_validators = [ExternalValidators::whitelisted_validators()].concat();
+        assert_eq!(ExternalValidators::validators(), expected_validators);
+    });
+}