adelapena commented on code in PR #1892: URL: https://github.com/apache/cassandra/pull/1892#discussion_r1052315531
########## src/java/org/apache/cassandra/cql3/functions/masking/HashMaskingFunction.java: ########## @@ -0,0 +1,141 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.cassandra.cql3.functions.masking; + +import java.nio.ByteBuffer; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.util.List; +import java.util.function.Supplier; +import javax.annotation.Nullable; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.Suppliers; + +import org.apache.cassandra.cql3.functions.FunctionFactory; +import org.apache.cassandra.cql3.functions.FunctionName; +import org.apache.cassandra.cql3.functions.FunctionParameter; +import org.apache.cassandra.cql3.functions.NativeFunction; +import org.apache.cassandra.db.marshal.AbstractType; +import org.apache.cassandra.db.marshal.BytesType; +import org.apache.cassandra.db.marshal.StringType; +import org.apache.cassandra.db.marshal.UTF8Type; +import org.apache.cassandra.exceptions.InvalidRequestException; +import org.apache.cassandra.transport.ProtocolVersion; + +/** + * A {@link MaskingFunction} that replaces the specified column value by its hash according to the specified + * algorithm. The available algorithms are those defined by the registered security {@link java.security.Provider}s. + * If no algorithm is passed to the function, the {@link #DEFAULT_ALGORITHM} will be used. + */ +public class HashMaskingFunction extends MaskingFunction +{ + public static final String NAME = "hash"; + + /** The default hashing algorithm to be used if no other algorithm is specified in the call to the function. */ + public static final String DEFAULT_ALGORITHM = "SHA-256"; + + // The default message digest is lazily built to prevent a failure during server startup if the algorithm is not + // available. That way, if the algorithm is not found only the calls to the function will fail. + private static final Supplier<MessageDigest> DEFAULT_DIGEST = Suppliers.memoize(() -> messageDigest(DEFAULT_ALGORITHM)); + private static final AbstractType<?>[] DEFAULT_ARGUMENTS = {}; + + /** The type of the supplied algorithm argument, {@code null} if that argument isn't supplied. */ + @Nullable + private final StringType algorithmArgumentType; + + private HashMaskingFunction(FunctionName name, AbstractType<?> inputType, @Nullable StringType algorithmArgumentType) + { + super(name, BytesType.instance, inputType, argumentsType(algorithmArgumentType)); + this.algorithmArgumentType = algorithmArgumentType; + } + + private static AbstractType<?>[] argumentsType(@Nullable StringType algorithmArgumentType) + { + // the algorithm argument is optional, so we will have different signatures depending on whether that argument + // is supplied or not + return algorithmArgumentType == null + ? DEFAULT_ARGUMENTS + : new AbstractType<?>[]{ algorithmArgumentType }; + } + + @Override + public final ByteBuffer execute(ProtocolVersion protocolVersion, List<ByteBuffer> parameters) + { + MessageDigest digest; + if (algorithmArgumentType == null || parameters.get(1) == null) + { + digest = DEFAULT_DIGEST.get(); + } + else + { + String algorithm = algorithmArgumentType.compose(parameters.get(1)); + digest = messageDigest(algorithm); + } + + return hash(digest, parameters.get(0)); + } + + @VisibleForTesting + @Nullable + static ByteBuffer hash(MessageDigest digest, ByteBuffer value) + { + if (value == null) + return null; + + byte[] hash = digest.digest(value.array()); + return BytesType.instance.compose(ByteBuffer.wrap(hash)); Review Comment: On regular queries we do change the `ResultSet` metadata, I have added some specific testing for this. Selector chaining should work as with using any other function. That might be more tricky when we attach functions to columns at CASSANDRA-18068, and we probably should forbid attaching this kind of type-altering functions. But using them as regular functions on SELECT queries shouldn't be a problem. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
