/**
* 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.hadoop.security;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URL;
import java.net.UnknownHostException;
import java.security.AccessController;
import java.util.Arrays;
import java.util.List;
import java.util.ServiceLoader;
import java.util.Set;
import javax.security.auth.Subject;
import javax.security.auth.kerberos.KerberosPrincipal;
import javax.security.auth.kerberos.KerberosTicket;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeys;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.TokenInfo;
import com.google.common.annotations.VisibleForTesting;
//this will need to be replaced someday when there is a suitable replacement
import sun.net.dns.ResolverConfiguration;
import sun.net.util.IPAddressUtil;
import sun.security.jgss.krb5.Krb5Util;
import sun.security.krb5.Credentials;
import sun.security.krb5.PrincipalName;
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class SecurityUtil {
public static final Log LOG = LogFactory.getLog(SecurityUtil.class);
public static final String HOSTNAME_PATTERN = "_HOST";
// controls whether buildTokenService will use an ip or host/ip as given
// by the user
@VisibleForTesting
static boolean useIpForTokenService;
@VisibleForTesting
static HostResolver hostResolver;
static {
boolean useIp = new Configuration().getBoolean(
CommonConfigurationKeys.HADOOP_SECURITY_TOKEN_SERVICE_USE_IP,
CommonConfigurationKeys.HADOOP_SECURITY_TOKEN_SERVICE_USE_IP_DEFAULT);
setTokenServiceUseIp(useIp);
}
/**
* For use only by tests and initialization
*/
@InterfaceAudience.Private
static void setTokenServiceUseIp(boolean flag) {
useIpForTokenService = flag;
hostResolver = !useIpForTokenService
? new QualifiedHostResolver()
: new StandardHostResolver();
}
/**
* Find the original TGT within the current subject's credentials. Cross-realm
* TGT's of the form "krbtgt/TWO.COM@ONE.COM" may be present.
*
* @return The TGT from the current subject
* @throws IOException
* if TGT can't be found
*/
private static KerberosTicket getTgtFromSubject() throws IOException {
Subject current = Subject.getSubject(AccessController.getContext());
if (current == null) {
throw new IOException(
"Can't get TGT from current Subject, because it is null");
}
Set<KerberosTicket> tickets = current
.getPrivateCredentials(KerberosTicket.class);
for (KerberosTicket t : tickets) {
if (isOriginalTGT(t))
return t;
}
throw new IOException("Failed to find TGT from current Subject:"+current);
}
/**
* TGS must have the server principal of the form "krbtgt/FOO@FOO".
* @param principal
* @return true or false
*/
static boolean
isTGSPrincipal(KerberosPrincipal principal) {
if (principal == null)
return false;
if (principal.getName().equals("krbtgt/" + principal.getRealm() +
"@" + principal.getRealm())) {
return true;
}
return false;
}
/**
* Check whether the server principal is the TGS's principal
* @param ticket the original TGT (the ticket that is obtained when a
* kinit is done)
* @return true or false
*/
protected static boolean isOriginalTGT(KerberosTicket ticket) {
return isTGSPrincipal(ticket.getServer());
}
/**
* Explicitly pull the service ticket for the specified host. This solves a
* problem with Java's Kerberos SSL problem where the client cannot
* authenticate against a cross-realm service. It is necessary for clients
* making kerberized https requests to call this method on the target URL
* to ensure that in a cross-realm environment the remote host will be
* successfully authenticated.
*
* This method is internal to Hadoop and should not be used by other
* applications. This method should not be considered stable or open:
* it will be removed when the Java behavior is changed.
*
* @param remoteHost Target URL the krb-https client will access
* @throws IOException if the service ticket cannot be retrieved
*/
public static void fetchServiceTicket(URL remoteHost) throws IOException {
if(!UserGroupInformation.isSecurityEnabled())
return;
String serviceName = "host/" + remoteHost.getHost();
if (LOG.isDebugEnabled())
LOG.debug("Fetching service ticket for host at: " + serviceName);
Credentials serviceCred = null;
try {
PrincipalName principal = new PrincipalName(serviceName,
PrincipalName.KRB_NT_SRV_HST);
serviceCred = Credentials.acquireServiceCreds(principal
.toString(), Krb5Util.ticketToCreds(getTgtFromSubject()));
} catch (Exception e) {
throw new IOException("Can't get service ticket for: "
+ serviceName, e);
}
if (serviceCred == null) {
throw new IOException("Can't get service ticket for " + serviceName);
}
Subject.getSubject(AccessController.getContext()).getPrivateCredentials()
.add(Krb5Util.credsToTicket(serviceCred));
}
/**
* Convert Kerberos principal name pattern to valid Kerberos principal
* names. It replaces hostname pattern with hostname, which should be
* fully-qualified domain name. If hostname is null or "0.0.0.0", it uses
* dynamically looked-up fqdn of the current host instead.
*
* @param principalConfig
* the Kerberos principal name conf value to convert
* @param hostname
* the fully-qualified domain name used for substitution
* @return converted Kerberos principal name
* @throws IOException if the client address cannot be determined
*/
public static String getServerPrincipal(String principalConfig,
String hostname) throws IOException {
String[] components = getComponents(principalConfig);
if (components == null || components.length != 3
|| !components[1].equals(HOSTNAME_PATTERN)) {
return principalConfig;
} else {
return replacePattern(components, hostname);
}
}
/**
* Convert Kerberos principal name pattern to valid Kerberos principal names.
* This method is similar to {@link #getServerPrincipal(String, String)},
* except 1) the reverse DNS lookup from addr to hostname is done only when
* necessary, 2) param addr can't be null (no default behavior of using local
* hostname when addr is null).
*
* @param principalConfig
* Kerberos principal name pattern to convert
* @param addr
* InetAddress of the host used for substitution
* @return converted Kerberos principal name
* @throws IOException if the client address cannot be determined
*/
public static String getServerPrincipal(String principalConfig,
InetAddress addr) throws IOException {
String[] components = getComponents(principalConfig);
if (components == null || components.length != 3
|| !components[1].equals(HOSTNAME_PATTERN)) {
return principalConfig;
} else {
if (addr == null) {
throw new IOException("Can't replace " + HOSTNAME_PATTERN
+ " pattern since client address is null");
}
return replacePattern(components, addr.getCanonicalHostName());
}
}
private static String[] getComponents(String principalConfig) {
if (principalConfig == null)
return null;
return principalConfig.split("[/@]");
}
private static String replacePattern(String[] components, String hostname)
throws IOException {
String fqdn = hostname;
if (fqdn == null || fqdn.equals("") || fqdn.equals("0.0.0.0")) {
fqdn = getLocalHostName();
}
return components[0] + "/" + fqdn.toLowerCase() + "@" + components[2];
}
static String getLocalHostName() throws UnknownHostException {
return InetAddress.getLocalHost().getCanonicalHostName();
}
/**
* Login as a principal specified in config. Substitute $host in
* user's Kerberos principal name with a dynamically looked-up fully-qualified
* domain name of the current host.
*
* @param conf
* conf to use
* @param keytabFileKey
* the key to look for keytab file in conf
* @param userNameKey
* the key to look for user's Kerberos principal name in conf
* @throws IOException if login fails
*/
public static void login(final Configuration conf,
final String keytabFileKey, final String userNameKey) throws IOException {
login(conf, keytabFileKey, userNameKey, getLocalHostName());
}
/**
* Login as a principal specified in config. Substitute $host in user's Kerberos principal
* name with hostname. If non-secure mode - return. If no keytab available -
* bail out with an exception
*
* @param conf
* conf to use
* @param keytabFileKey
* the key to look for keytab file in conf
* @param userNameKey
* the key to look for user's Kerberos principal name in conf
* @param hostname
* hostname to use for substitution
* @throws IOException if the config doesn't specify a keytab
*/
public static void login(final Configuration conf,
final String keytabFileKey, final String userNameKey, String hostname)
throws IOException {
if(! UserGroupInformation.isSecurityEnabled())
return;
String keytabFilename = conf.get(keytabFileKey);
if (keytabFilename == null || keytabFilename.length() == 0) {
throw new IOException("Running in secure mode, but config doesn't have a keytab");
}
String principalConfig = conf.get(userNameKey, System
.getProperty("user.name"));
String principalName = SecurityUtil.getServerPrincipal(principalConfig,
hostname);
UserGroupInformation.loginUserFromKeytab(principalName, keytabFilename);
}
/**
* create the service name for a Delegation token
* @param uri of the service
* @param defPort is used if the uri lacks a port
* @return the token service, or null if no authority
* @see #buildTokenService(InetSocketAddress)
*/
public static String buildDTServiceName(URI uri, int defPort) {
String authority = uri.getAuthority();
if (authority == null) {
return null;
}
InetSocketAddress addr = NetUtils.createSocketAddr(authority, defPort);
return buildTokenService(addr).toString();
}
/**
* Get the host name from the principal name of format <service>/host@realm.
* @param principalName principal name of format as described above
* @return host name if the the string conforms to the above format, else null
*/
public static String getHostFromPrincipal(String principalName) {
return new HadoopKerberosName(principalName).getHostName();
}
private static ServiceLoader<SecurityInfo> securityInfoProviders =
ServiceLoader.load(SecurityInfo.class);
private static SecurityInfo[] testProviders = new SecurityInfo[0];
/**
* Test setup method to register additional providers.
* @param providers a list of high priority providers to use
*/
@InterfaceAudience.Private
public static void setSecurityInfoProviders(SecurityInfo... providers) {
testProviders = providers;
}
/**
* Look up the KerberosInfo for a given protocol. It searches all known
* SecurityInfo providers.
* @param protocol the protocol class to get the information for
* @param conf configuration object
* @return the KerberosInfo or null if it has no KerberosInfo defined
*/
public static KerberosInfo
getKerberosInfo(Class<?> protocol, Configuration conf) {
synchronized (testProviders) {
for(SecurityInfo provider: testProviders) {
KerberosInfo result = provider.getKerberosInfo(protocol, conf);
if (result != null) {
return result;
}
}
}
synchronized (securityInfoProviders) {
for(SecurityInfo provider: securityInfoProviders) {
KerberosInfo result = provider.getKerberosInfo(protocol, conf);
if (result != null) {
return result;
}
}
}
return null;
}
/**
* Look up the TokenInfo for a given protocol. It searches all known
* SecurityInfo providers.
* @param protocol The protocol class to get the information for.
* @param conf Configuration object
* @return the TokenInfo or null if it has no KerberosInfo defined
*/
public static TokenInfo getTokenInfo(Class<?> protocol, Configuration conf) {
synchronized (testProviders) {
for(SecurityInfo provider: testProviders) {
TokenInfo result = provider.getTokenInfo(protocol, conf);
if (result != null) {
return result;
}
}
}
synchronized (securityInfoProviders) {
for(SecurityInfo provider: securityInfoProviders) {
TokenInfo result = provider.getTokenInfo(protocol, conf);
if (result != null) {
return result;
}
}
}
return null;
}
/**
* Decode the given token's service field into an InetAddress
* @param token from which to obtain the service
* @return InetAddress for the service
*/
public static InetSocketAddress getTokenServiceAddr(Token<?> token) {
return NetUtils.createSocketAddr(token.getService().toString());
}
/**
* Set the given token's service to the format expected by the RPC client
* @param token a delegation token
* @param addr the socket for the rpc connection
*/
public static void setTokenService(Token<?> token, InetSocketAddress addr) {
Text service = buildTokenService(addr);
if (token != null) {
token.setService(service);
if (LOG.isDebugEnabled()) {
LOG.debug("Acquired token "+token); // Token#toString() prints service
}
} else {
LOG.warn("Failed to get token for service "+service);
}
}
/**
* Construct the service key for a token
* @param addr InetSocketAddress of remote connection with a token
* @return "ip:port" or "host:port" depending on the value of
* hadoop.security.token.service.use_ip
*/
public static Text buildTokenService(InetSocketAddress addr) {
String host = null;
if (useIpForTokenService) {
if (addr.isUnresolved()) { // host has no ip address
throw new IllegalArgumentException(
new UnknownHostException(addr.getHostName())
);
}
host = addr.getAddress().getHostAddress();
} else {
host = addr.getHostName().toLowerCase();
}
return new Text(host + ":" + addr.getPort());
}
/**
* Construct the service key for a token
* @param uri of remote connection with a token
* @return "ip:port" or "host:port" depending on the value of
* hadoop.security.token.service.use_ip
*/
public static Text buildTokenService(URI uri) {
return buildTokenService(NetUtils.createSocketAddr(uri.getAuthority()));
}
/**
* Resolves a host subject to the security requirements determined by
* hadoop.security.token.service.use_ip.
*
* @param hostname host or ip to resolve
* @return a resolved host
* @throws UnknownHostException if the host doesn't exist
*/
@InterfaceAudience.Private
public static
InetAddress getByName(String hostname) throws UnknownHostException {
return hostResolver.getByName(hostname);
}
interface HostResolver {
InetAddress getByName(String host) throws UnknownHostException;
}
/**
* Uses standard java host resolution
*/
static class StandardHostResolver implements HostResolver {
public InetAddress getByName(String host) throws UnknownHostException {
return InetAddress.getByName(host);
}
}
/**
* This an alternate resolver with important properties that the standard
* java resolver lacks:
* 1) The hostname is fully qualified. This avoids security issues if not
* all hosts in the cluster do not share the same search domains. It
* also prevents other hosts from performing unnecessary dns searches.
* In contrast, InetAddress simply returns the host as given.
* 2) The InetAddress is instantiated with an exact host and IP to prevent
* further unnecessary lookups. InetAddress may perform an unnecessary
* reverse lookup for an IP.
* 3) A call to getHostName() will always return the qualified hostname, or
* more importantly, the IP if instantiated with an IP. This avoids
* unnecessary dns timeouts if the host is not resolvable.
* 4) Point 3 also ensures that if the host is re-resolved, ex. during a
* connection re-attempt, that a reverse lookup to host and forward
* lookup to IP is not performed since the reverse/forward mappings may
* not always return the same IP. If the client initiated a connection
* with an IP, then that IP is all that should ever be contacted.
*
* NOTE: this resolver is only used if:
* hadoop.security.token.service.use_ip=false
*/
protected static class QualifiedHostResolver implements HostResolver {
@SuppressWarnings("unchecked")
private List<String> searchDomains =
ResolverConfiguration.open().searchlist();
/**
* Create an InetAddress with a fully qualified hostname of the given
* hostname. InetAddress does not qualify an incomplete hostname that
* is resolved via the domain search list.
* {@link InetAddress#getCanonicalHostName()} will fully qualify the
* hostname, but it always return the A record whereas the given hostname
* may be a CNAME.
*
* @param host a hostname or ip address
* @return InetAddress with the fully qualified hostname or ip
* @throws UnknownHostException if host does not exist
*/
public InetAddress getByName(String host) throws UnknownHostException {
InetAddress addr = null;
if (IPAddressUtil.isIPv4LiteralAddress(host)) {
// use ipv4 address as-is
byte[] ip = IPAddressUtil.textToNumericFormatV4(host);
addr = InetAddress.getByAddress(host, ip);
} else if (IPAddressUtil.isIPv6LiteralAddress(host)) {
// use ipv6 address as-is
byte[] ip = IPAddressUtil.textToNumericFormatV6(host);
addr = InetAddress.getByAddress(host, ip);
} else if (host.endsWith(".")) {
// a rooted host ends with a dot, ex. "host."
// rooted hosts never use the search path, so only try an exact lookup
addr = getByExactName(host);
} else if (host.contains(".")) {
// the host contains a dot (domain), ex. "host.domain"
// try an exact host lookup, then fallback to search list
addr = getByExactName(host);
if (addr == null) {
addr = getByNameWithSearch(host);
}
} else {
// it's a simple host with no dots, ex. "host"
// try the search list, then fallback to exact host
InetAddress loopback = InetAddress.getByName(null);
if (host.equalsIgnoreCase(loopback.getHostName())) {
addr = InetAddress.getByAddress(host, loopback.getAddress());
} else {
addr = getByNameWithSearch(host);
if (addr == null) {
addr = getByExactName(host);
}
}
}
// unresolvable!
if (addr == null) {
throw new UnknownHostException(host);
}
return addr;
}
InetAddress getByExactName(String host) {
InetAddress addr = null;
// InetAddress will use the search list unless the host is rooted
// with a trailing dot. The trailing dot will disable any use of the
// search path in a lower level resolver. See RFC 1535.
String fqHost = host;
if (!fqHost.endsWith(".")) fqHost += ".";
try {
addr = getInetAddressByName(fqHost);
// can't leave the hostname as rooted or other parts of the system
// malfunction, ex. kerberos principals are lacking proper host
// equivalence for rooted/non-rooted hostnames
addr = InetAddress.getByAddress(host, addr.getAddress());
} catch (UnknownHostException e) {
// ignore, caller will throw if necessary
}
return addr;
}
InetAddress getByNameWithSearch(String host) {
InetAddress addr = null;
if (host.endsWith(".")) { // already qualified?
addr = getByExactName(host);
} else {
for (String domain : searchDomains) {
String dot = !domain.startsWith(".") ? "." : "";
addr = getByExactName(host + dot + domain);
if (addr != null) break;
}
}
return addr;
}
// implemented as a separate method to facilitate unit testing
InetAddress getInetAddressByName(String host) throws UnknownHostException {
return InetAddress.getByName(host);
}
void setSearchDomains(String ... domains) {
searchDomains = Arrays.asList(domains);
}
}
}