Don't pass validators' public keys with attestations (#186)

* Don't pass validators' public keys with attestations

* Update statement-table's Misbehaviour typedef

* Update network/router

* Expand MessageValidationData

* Try to fix tests

* Extend ApiContext

* Remove 'index_mapping' from the SessionParams

* Construct index_mapping from authorities

* Move index_mapping to TableContext

* Add test for index_mapping order

polkadot/network/src/gossip.rs

@@ -22,7 +22,7 @@ use substrate_network::consensus_gossip::{
 	ValidatorContext,
 };
 use polkadot_validation::SignedStatement;
-use polkadot_primitives::{Block, Hash, SessionKey};
+use polkadot_primitives::{Block, Hash, SessionKey, parachain::ValidatorIndex};
 use codec::Decode;
 
 use std::collections::HashMap;
@@ -120,19 +120,26 @@ impl RegisteredMessageValidator {
 	}
 }
 
-// data needed for validating gossip.
+/// The data needed for validating gossip.
 pub(crate) struct MessageValidationData {
 	/// The authorities at a block.
 	pub(crate) authorities: Vec<SessionKey>,
+	/// Mapping from validator index to `SessionKey`.
+	pub(crate) index_mapping: HashMap<ValidatorIndex, SessionKey>,
 }
 
 impl MessageValidationData {
 	fn check_statement(&self, relay_parent: &Hash, statement: &SignedStatement) -> bool {
-		self.authorities.contains(&statement.sender) &&
+		let sender = match self.index_mapping.get(&statement.sender) {
+			Some(val) => val,
+			None => return false,
+		};
+
+		self.authorities.contains(&sender) &&
 			::polkadot_validation::check_statement(
 				&statement.statement,
 				&statement.signature,
-				statement.sender.clone(),
+				sender.clone(),
 				relay_parent,
 			)
 	}

polkadot/network/src/router.rs

@@ -27,10 +27,9 @@ use sr_primitives::traits::{ProvideRuntimeApi, BlakeTwo256, Hash as HashT};
 use polkadot_validation::{
 	SharedTable, TableRouter, SignedStatement, GenericStatement, ParachainWork, Outgoing, Validated
 };
-use polkadot_primitives::{Block, Hash, SessionKey};
-use polkadot_primitives::parachain::{
-	Extrinsic, CandidateReceipt, ParachainHost, Id as ParaId, Message,
-	Collation, PoVBlock,
+use polkadot_primitives::{Block, Hash};
+use polkadot_primitives::parachain::{Extrinsic, CandidateReceipt, ParachainHost, Id as ParaId, Message,
+	ValidatorIndex, Collation, PoVBlock,
 };
 use gossip::RegisteredMessageValidator;
 
@@ -163,12 +162,14 @@ impl<P: ProvideRuntimeApi + Send + Sync + 'static, E, N, T> Router<P, E, N, T> w
 		);
 		// dispatch future work as necessary.
 		for (producer, statement) in producers.into_iter().zip(statements) {
-			self.fetcher.knowledge().lock().note_statement(statement.sender, &statement.statement);
+			if let Some(sender) = self.table.index_to_id(statement.sender) {
+				self.fetcher.knowledge().lock().note_statement(sender, &statement.statement);
 
-			if let Some(work) = producer.map(|p| self.create_work(c_hash, p)) {
-				trace!(target: "validation", "driving statement work to completion");
-				let work = work.select2(self.fetcher.exit().clone()).then(|_| Ok(()));
-				self.fetcher.executor().spawn(work);
+				if let Some(work) = producer.map(|p| self.create_work(c_hash, p)) {
+					trace!(target: "validation", "driving statement work to completion");
+					let work = work.select2(self.fetcher.exit().clone()).then(|_| Ok(()));
+					self.fetcher.executor().spawn(work);
+				}
 			}
 		}
 	}
@@ -270,8 +271,8 @@ impl<P, E, N: NetworkService, T> Drop for Router<P, E, N, T> {
 // A unique trace for valid statements issued by a validator.
 #[derive(Hash, PartialEq, Eq, Clone, Debug)]
 enum StatementTrace {
-	Valid(SessionKey, Hash),
-	Invalid(SessionKey, Hash),
+	Valid(ValidatorIndex, Hash),
+	Invalid(ValidatorIndex, Hash),
 }
 
 // helper for deferring statements whose associated candidate is unknown.
@@ -325,19 +326,17 @@ impl DeferredStatements {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use substrate_primitives::crypto::UncheckedInto;
-	use polkadot_primitives::parachain::ValidatorId;
 
 	#[test]
 	fn deferred_statements_works() {
 		let mut deferred = DeferredStatements::new();
 		let hash = [1; 32].into();
 		let sig = Default::default();
-		let sender: ValidatorId = [255; 32].unchecked_into();
+		let sender_index = 0;
 
 		let statement = SignedStatement {
 			statement: GenericStatement::Valid(hash),
-			sender: sender.clone(),
+			sender: sender_index,
 			signature: sig,
 		};
 
@@ -358,7 +357,7 @@ mod tests {
 
 			assert_eq!(traces.len(), 1);
 			assert_eq!(signed[0].clone(), statement);
-			assert_eq!(traces[0].clone(), StatementTrace::Valid(sender, hash));
+			assert_eq!(traces[0].clone(), StatementTrace::Valid(sender_index, hash));
 		}
 
 		// after draining

polkadot/network/src/tests/validation.rs

@@ -401,6 +401,7 @@ fn make_table(data: &ApiData, local_key: &AuthorityKeyring, parent_hash: Hash) -
 	).unwrap();
 
 	Arc::new(SharedTable::new(
+		data.validators.as_slice(),
 		group_info,
 		Arc::new(local_key.pair()),
 		parent_hash,

polkadot/network/src/validation.rs

@@ -24,10 +24,7 @@ use substrate_network::Context as NetContext;
 use substrate_network::consensus_gossip::{TopicNotification, MessageRecipient as GossipMessageRecipient};
 use polkadot_validation::{Network as ParachainNetwork, SharedTable, Collators, Statement, GenericStatement};
 use polkadot_primitives::{Block, BlockId, Hash, SessionKey};
-use polkadot_primitives::parachain::{
-	Id as ParaId, Collation, Extrinsic, ParachainHost, Message, CandidateReceipt,
-	CollatorId, ValidatorId, PoVBlock,
-};
+use polkadot_primitives::parachain::{Id as ParaId, Collation, Extrinsic, ParachainHost, Message, CandidateReceipt, CollatorId, ValidatorId, PoVBlock, ValidatorIndex};
 use codec::{Encode, Decode};
 
 use futures::prelude::*;
@@ -195,13 +192,21 @@ impl<P, E, N, T> ValidationNetwork<P, E, N, T> where
 		let task_executor = self.executor.clone();
 		let exit = self.exit.clone();
 		let message_validator = self.message_validator.clone();
+		let index_mapping = params.authorities
+			.iter()
+			.enumerate()
+			.map(|(i, k)| (i as ValidatorIndex, k.clone()))
+			.collect();
 
 		let (tx, rx) = oneshot::channel();
 		self.network.with_spec(move |spec, ctx| {
 			// before requesting messages, note live consensus session.
 			message_validator.note_session(
 				parent_hash,
-				MessageValidationData { authorities: params.authorities.clone() },
+				MessageValidationData {
+					authorities: params.authorities.clone(),
+					index_mapping,
+				},
 			);
 
 			let session = spec.new_validation_session(ctx, params);