verify chunk hashes in cli restore (#3241)

parity/snapshot.rs

@@ -66,6 +66,8 @@ pub struct SnapshotCommand {
 // helper for reading chunks from arbitrary reader and feeding them into the
 // service.
 fn restore_using<R: SnapshotReader>(snapshot: Arc<SnapshotService>, reader: &R, recover: bool) -> Result<(), String> {
+	use util::sha3::Hashable;
+
 	let manifest = reader.manifest();
 
 	info!("Restoring to block #{} (0x{:?})", manifest.block_number, manifest.block_hash);
@@ -93,6 +95,12 @@ fn restore_using<R: SnapshotReader>(snapshot: Arc<SnapshotService>, reader: &R,
 
  		let chunk = try!(reader.chunk(state_hash)
 			.map_err(|e| format!("Encountered error while reading chunk {:?}: {}", state_hash, e)));
+
+		let hash = chunk.sha3();
+		if hash != state_hash {
+			return Err(format!("Mismatched chunk hash. Expected {:?}, got {:?}", state_hash, hash));
+		}
+
  		snapshot.feed_state_chunk(state_hash, &chunk);
  	}
 
@@ -104,6 +112,11 @@ fn restore_using<R: SnapshotReader>(snapshot: Arc<SnapshotService>, reader: &R,
 
  		let chunk = try!(reader.chunk(block_hash)
 			.map_err(|e| format!("Encountered error while reading chunk {:?}: {}", block_hash, e)));
+
+		let hash = chunk.sha3();
+		if hash != block_hash {
+			return Err(format!("Mismatched chunk hash. Expected {:?}, got {:?}", block_hash, hash));
+		}
 		snapshot.feed_block_chunk(block_hash, &chunk);
 	}