A0-1820: implement substrate specific verifier for sync protocol (#864)

* Small refactor to prepare for verifier

* move justification verification to sync folder

* implement SessionVerifier cache

* implement verifier for VerifierCache

finality-aleph/src/crypto.rs

@@ -102,7 +102,7 @@ pub fn verify(authority: &AuthorityId, message: &[u8], signature: &Signature) ->
 
 /// Holds the public authority keys for a session allowing for verification of messages from that
 /// session.
-#[derive(Clone)]
+#[derive(PartialEq, Clone, Debug)]
 pub struct AuthorityVerifier {
     authorities: Vec<AuthorityId>,
 }

finality-aleph/src/nodes/mod.rs

@@ -3,30 +3,23 @@ mod validator_node;
 
 use std::{future::Future, sync::Arc};
 
-use aleph_primitives::{AuthorityId, SessionAuthorityData};
-use codec::Encode;
-use log::warn;
 pub use nonvalidator_node::run_nonvalidator_node;
 use sc_client_api::Backend;
 use sc_network::NetworkService;
 use sc_network_common::ExHashT;
-use sp_runtime::{
-    traits::{Block, Header, NumberFor},
-    RuntimeAppPublic,
-};
+use sp_runtime::traits::{Block, Header, NumberFor};
 pub use validator_node::run_validator_node;
 
 use crate::{
-    crypto::AuthorityVerifier,
     finalization::AlephFinalizer,
     justification::{
-        AlephJustification, JustificationHandler, JustificationRequestSchedulerImpl, SessionInfo,
-        SessionInfoProvider, Verifier,
+        JustificationHandler, JustificationRequestSchedulerImpl, SessionInfo, SessionInfoProvider,
     },
     last_block_of_session, mpsc,
     mpsc::UnboundedSender,
     session_id_from_block_num,
     session_map::ReadOnlySessionMap,
+    sync::SessionVerifier,
     BlockchainBackend, JustificationNotification, Metrics, MillisecsPerBlock, SessionPeriod,
 };
 
@@ -38,52 +31,6 @@ pub mod testing {
 /// Max amount of tries we can not update a finalized block number before we will clear requests queue
 const MAX_ATTEMPTS: u32 = 5;
 
-struct JustificationVerifier {
-    authority_verifier: AuthorityVerifier,
-    emergency_signer: Option<AuthorityId>,
-}
-
-impl From<SessionAuthorityData> for JustificationVerifier {
-    fn from(authority_data: SessionAuthorityData) -> Self {
-        JustificationVerifier {
-            authority_verifier: AuthorityVerifier::new(authority_data.authorities().to_vec()),
-            emergency_signer: authority_data.emergency_finalizer().clone(),
-        }
-    }
-}
-
-impl<B: Block> Verifier<B> for JustificationVerifier {
-    fn verify(&self, justification: &AlephJustification, hash: B::Hash) -> bool {
-        use AlephJustification::*;
-        let encoded_hash = hash.encode();
-        match justification {
-            CommitteeMultisignature(multisignature) => match self
-                .authority_verifier
-                .is_complete(&encoded_hash, multisignature)
-            {
-                true => true,
-                false => {
-                    warn!(target: "aleph-justification", "Bad multisignature for block hash #{:?} {:?}", hash, multisignature);
-                    false
-                }
-            },
-            EmergencySignature(signature) => match &self.emergency_signer {
-                Some(emergency_signer) => match emergency_signer.verify(&encoded_hash, signature) {
-                    true => true,
-                    false => {
-                        warn!(target: "aleph-justification", "Bad emergency signature for block hash #{:?} {:?}", hash, signature);
-                        false
-                    }
-                },
-                None => {
-                    warn!(target: "aleph-justification", "Received emergency signature for block with hash #{:?}, which has no emergency signer defined.", hash);
-                    false
-                }
-            },
-        }
-    }
-}
-
 struct JustificationParams<B: Block, H: ExHashT, C, BB> {
     pub network: Arc<NetworkService<B, H>>,
     pub client: Arc<C>,
@@ -110,10 +57,10 @@ impl SessionInfoProviderImpl {
 }
 
 #[async_trait::async_trait]
-impl<B: Block> SessionInfoProvider<B, JustificationVerifier> for SessionInfoProviderImpl {
-    async fn for_block_num(&self, number: NumberFor<B>) -> SessionInfo<B, JustificationVerifier> {
-        let current_session = session_id_from_block_num::<B>(number, self.session_period);
-        let last_block_height = last_block_of_session::<B>(current_session, self.session_period);
+impl<B: Block> SessionInfoProvider<B, SessionVerifier> for SessionInfoProviderImpl {
+    async fn for_block_num(&self, number: NumberFor<B>) -> SessionInfo<B, SessionVerifier> {
+        let current_session = session_id_from_block_num(number, self.session_period);
+        let last_block_height = last_block_of_session(current_session, self.session_period);
         let verifier = self
             .session_authorities
             .get(current_session)

finality-aleph/src/party/impls.rs

@@ -1,10 +1,11 @@
 use std::{marker::PhantomData, sync::Arc};
 
 use sc_client_api::Backend;
-use sp_runtime::traits::{Block as BlockT, NumberFor, SaturatedConversion};
+use sp_runtime::traits::{Block as BlockT, NumberFor};
 
 use crate::{
     party::traits::{Block, ChainState, SessionInfo},
+    session::{first_block_of_session, last_block_of_session, session_id_from_block_num},
     ClientForAleph, SessionId, SessionPeriod,
 };
 
@@ -44,14 +45,14 @@ impl SessionInfoImpl {
 
 impl<B: BlockT> SessionInfo<B> for SessionInfoImpl {
     fn session_id_from_block_num(&self, n: NumberFor<B>) -> SessionId {
-        SessionId(n.saturated_into::<u32>() / self.session_period.0)
+        session_id_from_block_num(n, self.session_period)
     }
 
     fn last_block_of_session(&self, session_id: SessionId) -> NumberFor<B> {
-        ((session_id.0 + 1) * self.session_period.0 - 1).into()
+        last_block_of_session(session_id, self.session_period)
     }
 
     fn first_block_of_session(&self, session_id: SessionId) -> NumberFor<B> {
-        (session_id.0 * self.session_period.0).into()
+        first_block_of_session(session_id, self.session_period)
     }
 }

finality-aleph/src/party/mocks.rs

@@ -14,7 +14,8 @@ use crate::{
         manager::AuthorityTask,
         traits::{Block, ChainState, NodeSessionManager, SessionInfo, SyncState},
     },
-    AuthorityId, NodeIndex, SessionId,
+    session::{first_block_of_session, last_block_of_session, session_id_from_block_num},
+    AuthorityId, NodeIndex, SessionId, SessionPeriod,
 };
 
 type AMutex<T> = Arc<Mutex<T>>;
@@ -183,25 +184,27 @@ impl NodeSessionManager for Arc<MockNodeSessionManager> {
 }
 
 pub struct MockSessionInfo {
-    pub session_period: u32,
+    pub session_period: SessionPeriod,
 }
 
 impl MockSessionInfo {
     pub fn new(session_period: u32) -> Self {
-        Self { session_period }
+        Self {
+            session_period: SessionPeriod(session_period),
+        }
     }
 }
 
 impl SessionInfo<SimpleBlock> for MockSessionInfo {
     fn session_id_from_block_num(&self, n: u32) -> SessionId {
-        SessionId(n / self.session_period)
+        session_id_from_block_num(n, self.session_period)
     }
 
     fn last_block_of_session(&self, session_id: SessionId) -> u32 {
-        (session_id.0 + 1) * self.session_period - 1
+        last_block_of_session(session_id, self.session_period)
     }
 
     fn first_block_of_session(&self, session_id: SessionId) -> u32 {
-        session_id.0 * self.session_period
+        first_block_of_session(session_id, self.session_period)
     }
 }

finality-aleph/src/session.rs

@@ -1,5 +1,8 @@
 use codec::{Decode, Encode};
-use sp_runtime::{traits::Block, SaturatedConversion};
+use sp_runtime::{
+    traits::{AtLeast32BitUnsigned, Block},
+    SaturatedConversion,
+};
 
 use crate::NumberFor;
 
@@ -12,8 +15,8 @@ pub struct SessionBoundaries<B: Block> {
 impl<B: Block> SessionBoundaries<B> {
     pub fn new(session_id: SessionId, period: SessionPeriod) -> Self {
         SessionBoundaries {
-            first_block: first_block_of_session::<B>(session_id, period),
-            last_block: last_block_of_session::<B>(session_id, period),
+            first_block: first_block_of_session(session_id, period),
+            last_block: last_block_of_session(session_id, period),
         }
     }
 
@@ -26,22 +29,40 @@ impl<B: Block> SessionBoundaries<B> {
     }
 }
 
-pub fn first_block_of_session<B: Block>(
+pub fn first_block_of_session<N: AtLeast32BitUnsigned>(
     session_id: SessionId,
     period: SessionPeriod,
-) -> NumberFor<B> {
+) -> N {
     (session_id.0 * period.0).into()
 }
 
-pub fn last_block_of_session<B: Block>(
+pub fn last_block_of_session<N: AtLeast32BitUnsigned>(
     session_id: SessionId,
     period: SessionPeriod,
-) -> NumberFor<B> {
+) -> N {
     ((session_id.0 + 1) * period.0 - 1).into()
 }
 
-pub fn session_id_from_block_num<B: Block>(num: NumberFor<B>, period: SessionPeriod) -> SessionId {
-    SessionId(num.saturated_into::<u32>() / period.0)
+pub fn session_id_from_block_num<N: AtLeast32BitUnsigned>(
+    num: N,
+    period: SessionPeriod,
+) -> SessionId {
+    SessionId((num / period.0.into()).saturated_into())
+}
+
+#[cfg(test)]
+pub mod testing {
+    use aleph_primitives::SessionAuthorityData;
+    use sp_runtime::testing::UintAuthorityId;
+
+    pub fn authority_data(from: u64, to: u64) -> SessionAuthorityData {
+        SessionAuthorityData::new(
+            (from..to)
+                .map(|id| UintAuthorityId(id).to_public_key())
+                .collect(),
+            None,
+        )
+    }
 }
 
 #[derive(Copy, Clone, Debug, Default, Eq, PartialEq, Hash, Ord, PartialOrd, Encode, Decode)]

finality-aleph/src/session_map.rs

@@ -313,15 +313,15 @@ where
     }
 
     async fn update_session(&mut self, session_id: SessionId, period: SessionPeriod) {
-        let first_block = first_block_of_session::<B>(session_id, period);
+        let first_block = first_block_of_session(session_id, period);
         self.handle_first_block_of_session(first_block, session_id)
             .await;
     }
 
     fn catch_up_boundaries(&self, period: SessionPeriod) -> (SessionId, SessionId) {
         let last_finalized = self.finality_notificator.last_finalized();
 
-        let current_session = session_id_from_block_num::<B>(last_finalized, period);
+        let current_session = session_id_from_block_num(last_finalized, period);
         let starting_session = SessionId(current_session.0.saturating_sub(PRUNING_THRESHOLD));
 
         (starting_session, current_session)
@@ -343,7 +343,7 @@ where
             let last_finalized = header.number();
             trace!(target: "aleph-session-updater", "got FinalityNotification about #{:?}", last_finalized);
 
-            let session_id = session_id_from_block_num::<B>(*last_finalized, period);
+            let session_id = session_id_from_block_num(*last_finalized, period);
 
             if last_updated >= session_id {
                 continue;
@@ -366,15 +366,14 @@ mod tests {
     use sc_block_builder::BlockBuilderProvider;
     use sc_utils::mpsc::tracing_unbounded;
     use sp_consensus::BlockOrigin;
-    use sp_runtime::testing::UintAuthorityId;
     use substrate_test_runtime_client::{
         ClientBlockImportExt, DefaultTestClientBuilderExt, TestClient, TestClientBuilder,
         TestClientBuilderExt,
     };
     use tokio::sync::oneshot::error::TryRecvError;
 
     use super::*;
-    use crate::testing::mocks::TBlock;
+    use crate::{session::testing::authority_data, testing::mocks::TBlock};
 
     struct MockProvider {
         pub session_map: HashMap<NumberFor<TBlock>, SessionAuthorityData>,
@@ -432,15 +431,6 @@ mod tests {
         }
     }
 
-    fn authority_data(from: u64, to: u64) -> SessionAuthorityData {
-        SessionAuthorityData::new(
-            (from..to)
-                .map(|id| UintAuthorityId(id).to_public_key())
-                .collect(),
-            None,
-        )
-    }
-
     fn n_new_blocks(client: &mut Arc<TestClient>, n: u64) -> Vec<TBlock> {
         (0..n)
             .map(|_| {

finality-aleph/src/sync/mod.rs

@@ -7,6 +7,8 @@ mod substrate;
 mod task_queue;
 mod ticker;
 
+pub use substrate::SessionVerifier;
+
 const LOG_TARGET: &str = "aleph-block-sync";
 
 /// The identifier of a block, the least amount of knowledge we can have about a block.
@@ -50,7 +52,7 @@ pub trait Verifier<J: Justification> {
 
     /// Verifies the raw justification and returns a full justification if successful, otherwise an
     /// error.
-    fn verify(&self, justification: J::Unverified) -> Result<J, Self::Error>;
+    fn verify(&mut self, justification: J::Unverified) -> Result<J, Self::Error>;
 }
 
 /// A facility for finalizing blocks using justifications.

finality-aleph/src/sync/substrate/mod.rs

@@ -11,13 +11,17 @@ use crate::{
 mod chain_status;
 mod finalizer;
 mod status_notifier;
+mod verification;
+
+pub use verification::SessionVerifier;
 
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct BlockId<H: SubstrateHeader<Number = BlockNumber>> {
     hash: H::Hash,
     number: H::Number,
 }
 
+/// An identifier uniquely specifying a block and its height.
 impl<SH: SubstrateHeader<Number = BlockNumber>> Hash for BlockId<SH> {
     fn hash<H>(&self, state: &mut H)
     where