Backports for stable (#6116)

* remove chunk to restore from pending set only upon successful import

* blacklist bad manifest hashes upon failure

* more checks before snapshot syncing

* Reverted tests

* revert submodule change

ethcore/src/snapshot/service.rs

@@ -46,6 +46,9 @@ struct Guard(bool, PathBuf);
 impl Guard {
 	fn new(path: PathBuf) -> Self { Guard(true, path) }
 
+	#[cfg(test)]
+	fn benign() -> Self { Guard(false, PathBuf::default()) }
+
 	fn disarm(mut self) { self.0 = false }
 }
 
@@ -120,7 +123,7 @@ impl Restoration {
 
 	// feeds a state chunk, aborts early if `flag` becomes false.
 	fn feed_state(&mut self, hash: H256, chunk: &[u8], flag: &AtomicBool) -> Result<(), Error> {
-		if self.state_chunks_left.remove(&hash) {
+		if self.state_chunks_left.contains(&hash) {
 			let len = snappy::decompress_into(chunk, &mut self.snappy_buffer)?;
 
 			self.state.feed(&self.snappy_buffer[..len], flag)?;
@@ -128,6 +131,8 @@ impl Restoration {
 			if let Some(ref mut writer) = self.writer.as_mut() {
 				writer.write_state_chunk(hash, chunk)?;
 			}
+
+			self.state_chunks_left.remove(&hash);
 		}
 
 		Ok(())
@@ -135,13 +140,15 @@ impl Restoration {
 
 	// feeds a block chunk
 	fn feed_blocks(&mut self, hash: H256, chunk: &[u8], engine: &Engine, flag: &AtomicBool) -> Result<(), Error> {
-		if self.block_chunks_left.remove(&hash) {
+		if self.block_chunks_left.contains(&hash) {
 			let len = snappy::decompress_into(chunk, &mut self.snappy_buffer)?;
 
 			self.blocks.feed(&self.snappy_buffer[..len], engine, flag)?;
 			if let Some(ref mut writer) = self.writer.as_mut() {
 				 writer.write_block_chunk(hash, chunk)?;
 			}
+
+			self.block_chunks_left.remove(&hash);
 		}
 
 		Ok(())
@@ -669,4 +676,49 @@ mod tests {
 		service.restore_state_chunk(Default::default(), vec![]);
 		service.restore_block_chunk(Default::default(), vec![]);
 	}
+
+	#[test]
+	fn cannot_finish_with_invalid_chunks() {
+		use util::{H256, FixedHash};
+		use util::kvdb::DatabaseConfig;
+
+		let spec = get_test_spec();
+		let dir = RandomTempPath::new();
+
+		let state_hashes: Vec<_> = (0..5).map(|_| H256::random()).collect();
+		let block_hashes: Vec<_> = (0..5).map(|_| H256::random()).collect();
+		let db_config = DatabaseConfig::with_columns(::db::NUM_COLUMNS);
+		let gb = spec.genesis_block();
+		let flag = ::std::sync::atomic::AtomicBool::new(true);
+
+		let params = RestorationParams {
+			manifest: ManifestData {
+				version: 2,
+				state_hashes: state_hashes.clone(),
+				block_hashes: block_hashes.clone(),
+				state_root: H256::default(),
+				block_number: 100000,
+				block_hash: H256::default(),
+			},
+			pruning: Algorithm::Archive,
+			db_path: dir.as_path().to_owned(),
+			db_config: &db_config,
+			writer: None,
+			genesis: &gb,
+			guard: Guard::benign(),
+		};
+
+		let mut restoration = Restoration::new(params).unwrap();
+		let definitely_bad_chunk = [1, 2, 3, 4, 5];
+
+		for hash in state_hashes {
+			assert!(restoration.feed_state(hash, &definitely_bad_chunk, &flag).is_err());
+			assert!(!restoration.is_done());
+		}
+
+		for hash in block_hashes {
+			assert!(restoration.feed_blocks(hash, &definitely_bad_chunk, &*spec.engine, &flag).is_err());
+			assert!(!restoration.is_done());
+		}
+	}
 }

sync/src/chain.rs

@@ -159,6 +159,7 @@ pub const SNAPSHOT_SYNC_PACKET_COUNT: u8 = 0x16;
 const MAX_SNAPSHOT_CHUNKS_DOWNLOAD_AHEAD: usize = 3;
 
 const MIN_SUPPORTED_SNAPSHOT_MANIFEST_VERSION: u64 = 1;
+const MAX_SUPPORTED_SNAPSHOT_MANIFEST_VERSION: u64 = 2;
 
 const WAIT_PEERS_TIMEOUT_SEC: u64 = 5;
 const STATUS_TIMEOUT_SEC: u64 = 5;
@@ -523,7 +524,8 @@ impl ChainSync {
 					sn > fork_block &&
 					self.highest_block.map_or(true, |highest| highest >= sn && (highest - sn) <= SNAPSHOT_RESTORE_THRESHOLD)
 				))
-				.filter_map(|(p, peer)| peer.snapshot_hash.map(|hash| (p, hash.clone())));
+				.filter_map(|(p, peer)| peer.snapshot_hash.map(|hash| (p, hash.clone())))
+				.filter(|&(_, ref hash)| !self.snapshot.is_known_bad(hash));
 
 			let mut snapshot_peers = HashMap::new();
 			let mut max_peers: usize = 0;
@@ -1020,6 +1022,7 @@ impl ChainSync {
 			trace!(target: "sync", "Ignoring snapshot manifest from unconfirmed peer {}", peer_id);
 			return Ok(());
 		}
+
 		self.clear_peer_download(peer_id);
 		if !self.reset_peer_asking(peer_id, PeerAsking::SnapshotManifest) || self.state != SyncState::SnapshotManifest {
 			trace!(target: "sync", "{}: Ignored unexpected/expired manifest", peer_id);
@@ -1037,13 +1040,32 @@ impl ChainSync {
 			}
 			Ok(manifest) => manifest,
 		};
-		if manifest.version < MIN_SUPPORTED_SNAPSHOT_MANIFEST_VERSION {
-			trace!(target: "sync", "{}: Snapshot manifest version too low: {}", peer_id, manifest.version);
+
+		let manifest_hash = manifest_rlp.as_raw().sha3();
+		let is_usable_version = manifest.version >= MIN_SUPPORTED_SNAPSHOT_MANIFEST_VERSION
+			&& manifest.version <= MAX_SUPPORTED_SNAPSHOT_MANIFEST_VERSION;
+
+		if !self.peers.get(&peer_id).map_or(false, |peer| peer.snapshot_hash == Some(manifest_hash)) {
+			trace!(target: "sync", "{}: Snapshot manifest hash {} mismatched with advertised", peer_id, manifest_hash);
 			io.disable_peer(peer_id);
 			self.continue_sync(io);
+
+			return Ok(());
+		}
+
+		if !is_usable_version {
+			trace!(target: "sync", "{}: Snapshot manifest version incompatible: {}", peer_id, manifest.version);
+			self.snapshot.note_bad(manifest_hash);
+
+			// temporarily disable the peer while we tune our peer set to those
+			// with usable snapshots. we don't try and download any rejected manifest
+			// again, so when we reconnect we can still full sync.
+			io.disable_peer(peer_id);;
+			self.continue_sync(io);
 			return Ok(());
 		}
-		self.snapshot.reset_to(&manifest, &manifest_rlp.as_raw().sha3());
+
+		self.snapshot.reset_to(&manifest, &manifest_hash);
 		io.snapshot_service().begin_restore(manifest);
 		self.state = SyncState::SnapshotData;
 
@@ -1068,10 +1090,18 @@ impl ChainSync {
 		}
 
 		// check service status
-		match io.snapshot_service().status() {
+		let status = io.snapshot_service().status();
+		match status {
 			RestorationStatus::Inactive | RestorationStatus::Failed => {
 				trace!(target: "sync", "{}: Snapshot restoration aborted", peer_id);
 				self.state = SyncState::WaitingPeers;
+
+				// only note bad if restoration failed.
+				if let (Some(hash), RestorationStatus::Failed) = (self.snapshot.snapshot_hash(), status) {
+					trace!(target: "sync", "Noting snapshot hash {} as bad", hash);
+					self.snapshot.note_bad(hash);
+				}
+
 				self.snapshot.clear();
 				self.continue_sync(io);
 				return Ok(());

sync/src/snapshot.rs

@@ -31,6 +31,7 @@ pub struct Snapshot {
 	downloading_chunks: HashSet<H256>,
 	completed_chunks: HashSet<H256>,
 	snapshot_hash: Option<H256>,
+	bad_hashes: HashSet<H256>,
 }
 
 impl Snapshot {
@@ -42,6 +43,7 @@ impl Snapshot {
 			downloading_chunks: HashSet::new(),
 			completed_chunks: HashSet::new(),
 			snapshot_hash: None,
+			bad_hashes: HashSet::new(),
 		}
 	}
 
@@ -104,6 +106,16 @@ impl Snapshot {
 		self.downloading_chunks.remove(hash);
 	}
 
+	// note snapshot hash as bad.
+	pub fn note_bad(&mut self, hash: H256) {
+		self.bad_hashes.insert(hash);
+	}
+
+	// whether snapshot hash is known to be bad.
+	pub fn is_known_bad(&self, hash: &H256) -> bool {
+		self.bad_hashes.contains(hash)
+	}
+
 	pub fn snapshot_hash(&self) -> Option<H256> {
 		self.snapshot_hash
 	}
@@ -200,5 +212,15 @@ mod test {
 		assert_eq!(snapshot.done_chunks(), snapshot.total_chunks());
 		assert_eq!(snapshot.snapshot_hash(), Some(manifest.into_rlp().sha3()));
 	}
+
+	#[test]
+	fn tracks_known_bad() {
+		let mut snapshot = Snapshot::new();
+		let hash = H256::random();
+
+		assert_eq!(snapshot.is_known_bad(&hash), false);
+		snapshot.note_bad(hash);
+		assert_eq!(snapshot.is_known_bad(&hash), true);
+	}
 }