CandidateDescriptor: disable collator signature and collator id usage

polkadot/node/core/prospective-parachains/src/fragment_chain/mod.rs

@@ -160,8 +160,6 @@ impl CandidateStorage {
 			state,
 			candidate: Arc::new(ProspectiveCandidate {
 				commitments: candidate.commitments,
-				collator: candidate.descriptor.collator,
-				collator_signature: candidate.descriptor.signature,
 				persisted_validation_data,
 				pov_hash: candidate.descriptor.pov_hash,
 				validation_code_hash: candidate.descriptor.validation_code_hash,

polkadot/node/subsystem-util/src/inclusion_emulator/mod.rs

@@ -117,9 +117,8 @@
 /// That means a few blocks of execution time lost, which is not a big deal for code upgrades
 /// in practice at most once every few weeks.
 use polkadot_primitives::{
-	async_backing::Constraints as PrimitiveConstraints, BlockNumber, CandidateCommitments,
-	CollatorId, CollatorSignature, Hash, HeadData, Id as ParaId, PersistedValidationData,
-	UpgradeRestriction, ValidationCodeHash,
+	async_backing::Constraints as PrimitiveConstraints, BlockNumber, CandidateCommitments, Hash,
+	HeadData, Id as ParaId, PersistedValidationData, UpgradeRestriction, ValidationCodeHash,
 };
 use std::{collections::HashMap, sync::Arc};
 
@@ -521,18 +520,13 @@ impl ConstraintModifications {
 /// The prospective candidate.
 ///
 /// This comprises the key information that represent a candidate
-/// without pinning it to a particular session. For example, everything
-/// to do with the collator's signature and commitments are represented
-/// here. But the erasure-root is not. This means that prospective candidates
+/// without pinning it to a particular session. For example commitments are
+/// represented here. But the erasure-root is not. This means that prospective candidates
 /// are not correlated to any session in particular.
 #[derive(Debug, Clone, PartialEq)]
 pub struct ProspectiveCandidate {
 	/// The commitments to the output of the execution.
 	pub commitments: CandidateCommitments,
-	/// The collator that created the candidate.
-	pub collator: CollatorId,
-	/// The signature of the collator on the payload.
-	pub collator_signature: CollatorSignature,
 	/// The persisted validation data used to create the candidate.
 	pub persisted_validation_data: PersistedValidationData,
 	/// The hash of the PoV.
@@ -800,10 +794,7 @@ fn validate_against_constraints(
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use polkadot_primitives::{
-		CollatorPair, HorizontalMessages, OutboundHrmpMessage, ValidationCode,
-	};
-	use sp_application_crypto::Pair;
+	use polkadot_primitives::{HorizontalMessages, OutboundHrmpMessage, ValidationCode};
 
 	#[test]
 	fn stack_modifications() {
@@ -1162,11 +1153,6 @@ mod tests {
 		constraints: &Constraints,
 		relay_parent: &RelayChainBlockInfo,
 	) -> ProspectiveCandidate {
-		let collator_pair = CollatorPair::generate().0;
-		let collator = collator_pair.public();
-
-		let sig = collator_pair.sign(b"blabla".as_slice());
-
 		ProspectiveCandidate {
 			commitments: CandidateCommitments {
 				upward_messages: Default::default(),
@@ -1176,8 +1162,6 @@ mod tests {
 				processed_downward_messages: 0,
 				hrmp_watermark: relay_parent.number,
 			},
-			collator,
-			collator_signature: sig,
 			persisted_validation_data: PersistedValidationData {
 				parent_head: constraints.required_parent.clone(),
 				relay_parent_number: relay_parent.number,

polkadot/primitives/src/v7/mod.rs

@@ -2040,10 +2040,14 @@ pub mod node_features {
 		/// Must not be enabled unless all validators and collators have stopped using `req_chunk`
 		/// protocol version 1. If it is enabled, validators can start systematic chunk recovery.
 		AvailabilityChunkMapping = 2,
+		/// Enables node side support of `CoreIndex` committed candidate receipts.
+		/// See [RFC-103](https://github.com/polkadot-fellows/RFCs/pull/103) for details.
+		/// Only enable if at least 2/3 of nodes support the feature.
+		CandidateReceiptV2 = 3,
 		/// First unassigned feature bit.
 		/// Every time a new feature flag is assigned it should take this value.
 		/// and this should be incremented.
-		FirstUnassigned = 3,
+		FirstUnassigned = 4,
 	}
 }
 

polkadot/runtime/parachains/src/builder.rs

@@ -30,21 +30,30 @@ use bitvec::{order::Lsb0 as BitOrderLsb0, vec::BitVec};
 use frame_support::pallet_prelude::*;
 use frame_system::pallet_prelude::*;
 use polkadot_primitives::{
-	collator_signature_payload, node_features::FeatureIndex, AvailabilityBitfield, BackedCandidate,
-	CandidateCommitments, CandidateDescriptor, CandidateHash, CollatorId, CollatorSignature,
-	CommittedCandidateReceipt, CompactStatement, CoreIndex, DisputeStatement, DisputeStatementSet,
-	GroupIndex, HeadData, Id as ParaId, IndexedVec, InherentData as ParachainsInherentData,
-	InvalidDisputeStatementKind, PersistedValidationData, SessionIndex, SigningContext,
-	UncheckedSigned, ValidDisputeStatementKind, ValidationCode, ValidatorId, ValidatorIndex,
-	ValidityAttestation,
+	node_features::FeatureIndex, AvailabilityBitfield, BackedCandidate, CandidateCommitments,
+	CandidateDescriptor, CandidateHash, CollatorId, CollatorSignature, CommittedCandidateReceipt,
+	CompactStatement, CoreIndex, DisputeStatement, DisputeStatementSet, GroupIndex, HeadData,
+	Id as ParaId, IndexedVec, InherentData as ParachainsInherentData, InvalidDisputeStatementKind,
+	PersistedValidationData, SessionIndex, SigningContext, UncheckedSigned,
+	ValidDisputeStatementKind, ValidationCode, ValidatorId, ValidatorIndex, ValidityAttestation,
 };
-use sp_core::{sr25519, H256};
+use sp_core::{sr25519, ByteArray, H256};
 use sp_runtime::{
 	generic::Digest,
 	traits::{Header as HeaderT, One, TrailingZeroInput, Zero},
 	RuntimeAppPublic,
 };
 
+/// Create a null collator id.
+pub fn dummy_collator() -> CollatorId {
+	CollatorId::from_slice(&vec![0u8; 32]).expect("32 bytes; qed")
+}
+
+/// Create a null collator signature.
+pub fn dummy_collator_signature() -> CollatorSignature {
+	CollatorSignature::from_slice(&vec![0u8; 64]).expect("64 bytes; qed")
+}
+
 fn mock_validation_code() -> ValidationCode {
 	ValidationCode(vec![1, 2, 3])
 }
@@ -584,7 +593,6 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 
 						// This generates a pair and adds it to the keystore, returning just the
 						// public.
-						let collator_public = CollatorId::generate_pair(None);
 						let header = Self::header(self.block_number);
 						let relay_parent = header.hash();
 
@@ -614,14 +622,6 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 
 						let pov_hash = Default::default();
 						let validation_code_hash = mock_validation_code().hash();
-						let payload = collator_signature_payload(
-							&relay_parent,
-							&para_id,
-							&persisted_validation_data_hash,
-							&pov_hash,
-							&validation_code_hash,
-						);
-						let signature = collator_public.sign(&payload).unwrap();
 
 						let mut past_code_meta =
 							paras::ParaPastCodeMeta::<BlockNumberFor<T>>::default();
@@ -634,11 +634,11 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 							descriptor: CandidateDescriptor::<T::Hash> {
 								para_id,
 								relay_parent,
-								collator: collator_public,
+								collator: dummy_collator(),
 								persisted_validation_data_hash,
 								pov_hash,
 								erasure_root: Default::default(),
-								signature,
+								signature: dummy_collator_signature(),
 								para_head: head_data.hash(),
 								validation_code_hash,
 							},

polkadot/runtime/parachains/src/inclusion/mod.rs

@@ -338,8 +338,6 @@ pub mod pallet {
 		InsufficientBacking,
 		/// Invalid (bad signature, unknown validator, etc.) backing.
 		InvalidBacking,
-		/// Collator did not sign PoV.
-		NotCollatorSigned,
 		/// The validation data hash does not match expected.
 		ValidationDataHashMismatch,
 		/// The downward message queue is not processed correctly.
@@ -1222,7 +1220,6 @@ impl<T: Config> CandidateCheckContext<T> {
 	///
 	/// Assures:
 	///  * relay-parent in-bounds
-	///  * collator signature check passes
 	///  * code hash of commitments matches current code hash
 	///  * para head in the descriptor and commitments match
 	///
@@ -1259,11 +1256,6 @@ impl<T: Config> CandidateCheckContext<T> {
 			);
 		}
 
-		ensure!(
-			backed_candidate_receipt.descriptor().check_collator_signature().is_ok(),
-			Error::<T>::NotCollatorSigned,
-		);
-
 		let validation_code_hash = paras::CurrentCodeHash::<T>::get(para_id)
 			// A candidate for a parachain without current validation code is not scheduled.
 			.ok_or_else(|| Error::<T>::UnscheduledCandidate)?;

polkadot/runtime/parachains/src/inclusion/tests.rs

@@ -1545,16 +1545,52 @@ fn candidate_checks() {
 				None,
 			);
 
-			assert_noop!(
-				ParaInclusion::process_candidates(
-					&allowed_relay_parents,
-					&vec![(thread_a_assignment.0, vec![(backed, thread_a_assignment.1)])]
-						.into_iter()
-						.collect(),
-					&group_validators,
-					false
-				),
-				Error::<Test>::NotCollatorSigned
+			let ProcessedCandidates {
+				core_indices: occupied_cores,
+				candidate_receipt_with_backing_validator_indices,
+			} = ParaInclusion::process_candidates(
+				&allowed_relay_parents,
+				&vec![(thread_a_assignment.0, vec![(backed.clone(), thread_a_assignment.1)])]
+					.into_iter()
+					.collect(),
+				&group_validators,
+				false,
+			)
+			.expect("candidate is accepted with bad collator signature");
+
+			assert_eq!(occupied_cores, vec![(CoreIndex::from(2), thread_a)]);
+
+			let mut expected = std::collections::HashMap::<
+				CandidateHash,
+				(CandidateReceipt, Vec<(ValidatorIndex, ValidityAttestation)>),
+			>::new();
+			let backed_candidate = backed;
+			let candidate_receipt_with_backers = expected
+				.entry(backed_candidate.hash())
+				.or_insert_with(|| (backed_candidate.receipt(), Vec::new()));
+			let (validator_indices, _maybe_core_index) =
+				backed_candidate.validator_indices_and_core_index(true);
+			assert_eq!(backed_candidate.validity_votes().len(), validator_indices.count_ones());
+			candidate_receipt_with_backers.1.extend(
+				validator_indices
+					.iter()
+					.enumerate()
+					.filter(|(_, signed)| **signed)
+					.zip(backed_candidate.validity_votes().iter().cloned())
+					.filter_map(|((validator_index_within_group, _), attestation)| {
+						let grp_idx = GroupIndex(2);
+						group_validators(grp_idx).map(|validator_indices| {
+							(validator_indices[validator_index_within_group], attestation)
+						})
+					}),
+			);
+
+			assert_eq!(
+				expected,
+				candidate_receipt_with_backing_validator_indices
+					.into_iter()
+					.map(|c| (c.0.hash(), c))
+					.collect()
 			);
 		}
 

prdoc/pr_4665.prdoc

@@ -0,0 +1,21 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: "Remove runtime collator signature checks"
+
+doc:
+  - audience: [Runtime Dev, Node Dev]
+    description: |
+      Removes runtime collator signature checks, but these are still being done on the node. Remove collator 
+      and signature from the `ProspectiveCandidate` definition in the inclusion emulator. Add 
+      `CandidateReceiptV2` node feature bit.
+
+crates: 
+- name: polkadot-primitives
+  bump: minor
+- name: polkadot-node-subsystem-util
+  bump: minor
+- name: polkadot-node-core-prospective-parachains
+  bump: patch
+- name: polkadot-runtime-parachains
+  bump: patch