org.apache.accumulo.server.security.UserImpersonation.java Source code

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/*
 * 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.accumulo.server.security;

import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.apache.accumulo.core.conf.AccumuloConfiguration;
import org.apache.accumulo.core.conf.Property;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * When SASL is enabled, this parses properties from the site configuration to build up a set of all users capable of impersonating another user, the users
 * which may be impersonated and the hosts in which the impersonator may issue requests from.
 *
 * <code>INSTANCE_RPC_SASL_PROXYUSERS=rpc_user={allowed_accumulo_users=[...], allowed_client_hosts=[...]</code>
 * <code>INSTANCE_RPC_SASL_ALLOWED_USER_IMPERSONATION=rpc_user:user,user,user;...</code>
 * <code>INSTANCE_RPC_SASL_ALLOWED_HOST_IMPERSONATION=host,host:host...</code>
 *
 * @see Property#INSTANCE_RPC_SASL_ALLOWED_USER_IMPERSONATION
 * @see Property#INSTANCE_RPC_SASL_ALLOWED_HOST_IMPERSONATION
 */
public class UserImpersonation {

    private static final Logger log = LoggerFactory.getLogger(UserImpersonation.class);
    private static final Set<String> ALWAYS_TRUE = new AlwaysTrueSet<>();
    private static final String ALL = "*", USERS = "users", HOSTS = "hosts";

    public static class AlwaysTrueSet<T> implements Set<T> {

        @Override
        public int size() {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean isEmpty() {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean contains(Object o) {
            return true;
        }

        @Override
        public Iterator<T> iterator() {
            throw new UnsupportedOperationException();
        }

        @Override
        public Object[] toArray() {
            throw new UnsupportedOperationException();
        }

        @Override
        public <E> E[] toArray(E[] a) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean add(T e) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean remove(Object o) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean containsAll(Collection<?> c) {
            return true;
        }

        @Override
        public boolean addAll(Collection<? extends T> c) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean retainAll(Collection<?> c) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean removeAll(Collection<?> c) {
            throw new UnsupportedOperationException();
        }

        @Override
        public void clear() {
            throw new UnsupportedOperationException();
        }
    }

    public static class UsersWithHosts {
        private Set<String> users = new HashSet<>(), hosts = new HashSet<>();
        private boolean allUsers, allHosts;

        public UsersWithHosts() {
            allUsers = allHosts = false;
        }

        public UsersWithHosts(Set<String> users, Set<String> hosts) {
            this();
            this.users = users;
            this.hosts = hosts;
        }

        public Set<String> getUsers() {
            if (allUsers) {
                return ALWAYS_TRUE;
            }
            return users;
        }

        public Set<String> getHosts() {
            if (allHosts) {
                return ALWAYS_TRUE;
            }
            return hosts;
        }

        public boolean acceptsAllUsers() {
            return allUsers;
        }

        public void setAcceptAllUsers(boolean allUsers) {
            this.allUsers = allUsers;
        }

        public boolean acceptsAllHosts() {
            return allHosts;
        }

        public void setAcceptAllHosts(boolean allHosts) {
            this.allHosts = allHosts;
        }

        public void setUsers(Set<String> users) {
            this.users = users;
            allUsers = false;
        }

        public void setHosts(Set<String> hosts) {
            this.hosts = hosts;
            allHosts = false;
        }
    }

    private final Map<String, UsersWithHosts> proxyUsers;

    @SuppressWarnings("deprecation")
    public UserImpersonation(AccumuloConfiguration conf) {
        proxyUsers = new HashMap<>();

        // Property.INSTANCE_RPC_SASL_ALLOWED_USER_IMPERSONATION is treated as the "new config style" switch
        final String userConfig = conf.get(Property.INSTANCE_RPC_SASL_ALLOWED_USER_IMPERSONATION);
        if (!Property.INSTANCE_RPC_SASL_ALLOWED_USER_IMPERSONATION.getDefaultValue().equals(userConfig)) {
            String hostConfig = conf.get(Property.INSTANCE_RPC_SASL_ALLOWED_HOST_IMPERSONATION);
            parseOnelineConfiguration(userConfig, hostConfig);
        } else {
            // Otherwise, assume the old-style
            parseMultiPropertyConfiguration(conf.getAllPropertiesWithPrefix(Property.INSTANCE_RPC_SASL_PROXYUSERS));
        }
    }

    /**
     * Parses the impersonation configuration for all users from a single property.
     *
     * @param userConfigString
     *          Semi-colon separated list of {@code remoteUser:alloweduser,alloweduser,...}.
     * @param hostConfigString
     *          Semi-colon separated list of hosts.
     */
    private void parseOnelineConfiguration(String userConfigString, String hostConfigString) {
        // Pull out the config values, defaulting to at least one value
        final String[] userConfigs;
        if (userConfigString.trim().isEmpty()) {
            userConfigs = new String[] { "" };
        } else {
            userConfigs = StringUtils.split(userConfigString, ';');
        }
        final String[] hostConfigs;
        if (hostConfigString.trim().isEmpty()) {
            hostConfigs = new String[] { "" };
        } else {
            hostConfigs = StringUtils.split(hostConfigString, ';');
        }

        if (userConfigs.length != hostConfigs.length) {
            String msg = String.format(
                    "Should have equal number of user and host impersonation elements in configuration. Got %d and %d elements, respectively.",
                    userConfigs.length, hostConfigs.length);
            throw new IllegalArgumentException(msg);
        }

        for (int i = 0; i < userConfigs.length; i++) {
            final String userConfig = userConfigs[i];
            final String hostConfig = hostConfigs[i];

            final String[] splitUserConfig = StringUtils.split(userConfig, ':');
            if (2 != splitUserConfig.length) {
                throw new IllegalArgumentException(
                        "Expect a single colon-separated pair, but found '" + userConfig + "'");
            }

            final String remoteUser = splitUserConfig[0];
            final String allowedImpersonationsForRemoteUser = splitUserConfig[1];
            final UsersWithHosts usersWithHosts = new UsersWithHosts();

            proxyUsers.put(remoteUser.trim(), usersWithHosts);

            if (ALL.equals(allowedImpersonationsForRemoteUser)) {
                usersWithHosts.setAcceptAllUsers(true);
            } else {
                String[] allowedUsers = StringUtils.split(allowedImpersonationsForRemoteUser, ",");
                Set<String> usersSet = new HashSet<>();
                usersSet.addAll(Arrays.asList(allowedUsers));
                usersWithHosts.setUsers(usersSet);
            }

            if (ALL.equals(hostConfig)) {
                usersWithHosts.setAcceptAllHosts(true);
            } else {
                String[] allowedHosts = StringUtils.split(hostConfig, ",");
                Set<String> hostsSet = new HashSet<>();
                hostsSet.addAll(Arrays.asList(allowedHosts));
                usersWithHosts.setHosts(hostsSet);
            }
        }
    }

    /**
     * Parses all properties that start with {@link Property#INSTANCE_RPC_SASL_PROXYUSERS}. This approach was the original configuration method, but does not work
     * with Ambari.
     *
     * @param configProperties
     *          The relevant configuration properties for impersonation.
     */
    @SuppressWarnings("javadoc")
    private void parseMultiPropertyConfiguration(Map<String, String> configProperties) {
        @SuppressWarnings("deprecation")
        final String configKey = Property.INSTANCE_RPC_SASL_PROXYUSERS.getKey();
        for (Entry<String, String> entry : configProperties.entrySet()) {
            String aclKey = entry.getKey().substring(configKey.length());
            int index = aclKey.lastIndexOf('.');

            if (-1 == index) {
                throw new RuntimeException("Expected 2 elements in key suffix: " + aclKey);
            }

            final String remoteUser = aclKey.substring(0, index).trim(),
                    usersOrHosts = aclKey.substring(index + 1).trim();
            UsersWithHosts usersWithHosts = proxyUsers.get(remoteUser);
            if (null == usersWithHosts) {
                usersWithHosts = new UsersWithHosts();
                proxyUsers.put(remoteUser, usersWithHosts);
            }

            if (USERS.equals(usersOrHosts)) {
                String userString = entry.getValue().trim();
                if (ALL.equals(userString)) {
                    usersWithHosts.setAcceptAllUsers(true);
                } else if (!usersWithHosts.acceptsAllUsers()) {
                    Set<String> users = usersWithHosts.getUsers();
                    if (null == users) {
                        users = new HashSet<>();
                        usersWithHosts.setUsers(users);
                    }
                    String[] userValues = StringUtils.split(userString, ',');
                    users.addAll(Arrays.<String>asList(userValues));
                }
            } else if (HOSTS.equals(usersOrHosts)) {
                String hostsString = entry.getValue().trim();
                if (ALL.equals(hostsString)) {
                    usersWithHosts.setAcceptAllHosts(true);
                } else if (!usersWithHosts.acceptsAllHosts()) {
                    Set<String> hosts = usersWithHosts.getHosts();
                    if (null == hosts) {
                        hosts = new HashSet<>();
                        usersWithHosts.setHosts(hosts);
                    }
                    String[] hostValues = StringUtils.split(hostsString, ',');
                    hosts.addAll(Arrays.<String>asList(hostValues));
                }
            } else {
                log.debug("Ignoring key " + aclKey);
            }
        }
    }

    public UsersWithHosts get(String remoteUser) {
        return proxyUsers.get(remoteUser);
    }

}