src/main/java/org/apache/cassandra/sidecar/utils/CassandraInputValidator.java

/*
 * 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.sidecar.utils;

import java.io.File;
import java.util.Objects;

import com.google.inject.Inject;
import com.google.inject.Singleton;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.vertx.ext.web.handler.HttpException;
import org.apache.cassandra.sidecar.common.data.Name;
import org.apache.cassandra.sidecar.config.CassandraInputValidationConfiguration;
import org.apache.cassandra.sidecar.config.yaml.CassandraInputValidationConfigurationImpl;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.VisibleForTesting;

/**
 * Miscellaneous methods used for validation.
 */
@Singleton
public class CassandraInputValidator
{
    private final CassandraInputValidationConfiguration validationConfiguration;

    /**
     * Constructs a new object with the provided {@code validationConfiguration}
     *
     * @param validationConfiguration a validation configuration
     */
    @Inject
    public CassandraInputValidator(CassandraInputValidationConfiguration validationConfiguration)
    {
        this.validationConfiguration = validationConfiguration;
    }

    @VisibleForTesting
    public CassandraInputValidator()
    {
        this(new CassandraInputValidationConfigurationImpl());
    }

    /**
     * Validates that the {@code keyspace} is not {@code null}, that it contains valid characters, and that it's
     * not a forbidden keyspace.
     *
     * @param keyspace the name of the Cassandra keyspace to validate
     * @return the validated {@code keyspace}
     * @throws NullPointerException when the {@code keyspace} is {@code null}
     * @throws HttpException        when the {@code keyspace} contains invalid characters in the name or when the
     *                              keyspace is forbidden
     */
    public Name validateKeyspaceName(@NotNull String keyspace)
    {
        Objects.requireNonNull(keyspace, "keyspace must not be null");
        String unquoted = removeQuotesIfNecessary(keyspace);
        // whether the input is quoted from the source
        boolean isQuoted = !unquoted.equals(keyspace);
        validatePattern(unquoted, keyspace, "keyspace", isQuoted);
        if (validationConfiguration.forbiddenKeyspaces().contains(unquoted))
            throw new HttpException(HttpResponseStatus.FORBIDDEN.code(), "Forbidden keyspace: " + keyspace);
        return new Name(unquoted, keyspace);
    }

    /**
     * Validates that the {@code tableName} is not {@code null}, and it contains allowed character for Cassandra
     * table names.
     *
     * @param tableName the name of the Cassandra table to validate
     * @return the validated {@code tableName}
     * @throws NullPointerException when the {@code tableName} is {@code null}
     * @throws HttpException        when the {@code tableName} contains invalid characters in the name
     */
    public Name validateTableName(@NotNull String tableName)
    {
        Objects.requireNonNull(tableName, "tableName must not be null");
        String unquoted = removeQuotesIfNecessary(tableName);
        boolean isQuoted = !unquoted.equals(tableName);
        validatePattern(unquoted, tableName, "table name", isQuoted);
        return new Name(unquoted, tableName);
    }

    /**
     * Validates that the {@code snapshotName} is not {@code null}, and it contains allowed character for the
     * Cassandra snapshot names.
     *
     * @param snapshotName the name of the Cassandra snapshot to validate
     * @return the validated {@code snapshotName}
     * @throws NullPointerException when the {@code snapshotName} is {@code null}
     * @throws HttpException        when the {@code snapshotName} contains invalid characters in the name
     */
    public String validateSnapshotName(@NotNull String snapshotName)
    {
        Objects.requireNonNull(snapshotName, "snapshotName must not be null");
        //  most UNIX systems only disallow file separator and null characters for directory names
        if (snapshotName.contains(File.separator) || snapshotName.contains("\0"))
            throw new HttpException(HttpResponseStatus.BAD_REQUEST.code(),
                                    "Invalid characters in snapshot name: " + snapshotName);
        return snapshotName;
    }

    /**
     * Validates that the {@code componentName} is not {@code null}, and it contains allowed names for the
     * Cassandra SSTable component.
     *
     * @param componentName the name of the SSTable component to validate
     * @return the validated {@code componentName}
     * @throws NullPointerException when the {@code componentName} is null
     * @throws HttpException        when the {@code componentName} is not valid
     */
    public String validateComponentName(@NotNull String componentName)
    {
        return validateComponentNameByRegex(componentName,
                                            validationConfiguration.allowedPatternForComponentName());
    }

    /**
     * Validates that the {@code componentName} is not {@code null}, and it contains a subset of allowed names for the
     * Cassandra SSTable component.
     *
     * @param componentName the name of the SSTable component to validate
     * @return the validated {@code componentName}
     * @throws NullPointerException when the {@code componentName} is null
     * @throws HttpException        when the {@code componentName} is not a valid name for the configured restricted
     *                              component name
     */
    public String validateRestrictedComponentName(@NotNull String componentName)
    {
        return validateComponentNameByRegex(componentName,
                                            validationConfiguration.allowedPatternForRestrictedComponentName());
    }

    /**
     * Validates the {@code componentName} against the provided {@code regex}.
     *
     * @param componentName the name of the SSTable component
     * @param regex         the regex for validation
     * @return the validated {@code componentName}
     * @throws NullPointerException when the {@code componentName} is null
     * @throws HttpException        when the {@code componentName} does not match the provided regex
     */
    @NotNull
    private String validateComponentNameByRegex(String componentName, String regex)
    {
        Objects.requireNonNull(componentName, "componentName must not be null");
        if (!componentName.matches(regex))
            throw new HttpException(HttpResponseStatus.BAD_REQUEST.code(),
                                    "Invalid component name: " + componentName);
        return componentName;
    }

    /**
     * Validates that the {@code unquotedInput} matches the {@code patternWordChars}
     *
     * @param unquotedInput      the unquoted input
     * @param quotedInput        the original input used for the exception message
     * @param name               a name for the exception message
     * @param isQuotedFromSource whether the name was quoted from source
     * @throws HttpException when the {@code unquotedInput} does not match the pattern
     */
    public void validatePattern(String unquotedInput, String quotedInput, String name, boolean isQuotedFromSource)
    {
        String pattern = isQuotedFromSource
                         ? validationConfiguration.allowedPatternForQuotedName()
                         : validationConfiguration.allowedPatternForName();

        if (!unquotedInput.matches(pattern))
            throw new HttpException(HttpResponseStatus.BAD_REQUEST.code(),
                                    "Invalid characters in " + name + ": " + quotedInput);
    }

    /**
     * Removes the surrounding quotes for the name, if the quotes are present. Otherwise, returns the original
     * input.
     *
     * @param name the name
     * @return the {@code name} without surrounding quotes
     */
    static String removeQuotesIfNecessary(String name)
    {
        if (name == null || name.length() <= 1
            || name.charAt(0) != '"' || name.charAt(name.length() - 1) != '"')
        {
            return name;
        }
        return name.substring(1, name.length() - 1);
    }
}