/*
* @(#)Sasl.java 1.21 04/05/05
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.security.sasl;
import javax.security.auth.callback.CallbackHandler;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.HashSet;
import java.util.Collections;
import java.security.Provider;
import java.security.Security;
/**
* A static class for creating SASL clients and servers.
*<p>
* This class defines the policy of how to locate, load, and instantiate
* SASL clients and servers.
*<p>
* For example, an application or library gets a SASL client by doing
* something like:
*<blockquote><pre>
* SaslClient sc = Sasl.createSaslClient(mechanisms,
* authorizationId, protocol, serverName, props, callbackHandler);
*</pre></blockquote>
* It can then proceed to use the instance to create an authentication connection.
*<p>
* Similarly, a server gets a SASL server by using code that looks as follows:
*<blockquote><pre>
* SaslServer ss = Sasl.createSaslServer(mechanism,
* protocol, serverName, props, callbackHandler);
*</pre></blockquote>
*
* @since 1.5
*
* @author Rosanna Lee
* @author Rob Weltman
*/
public class Sasl {
// Cannot create one of these
private Sasl() {
}
/**
* The name of a property that specifies the quality-of-protection to use.
* The property contains a comma-separated, ordered list
* of quality-of-protection values that the
* client or server is willing to support. A qop value is one of
* <ul>
* <li><tt>"auth"</tt> - authentication only</li>
* <li><tt>"auth-int"</tt> - authentication plus integrity protection</li>
* <li><tt>"auth-conf"</tt> - authentication plus integrity and confidentiality
* protection</li>
* </ul>
*
* The order of the list specifies the preference order of the client or
* server. If this property is absent, the default qop is <tt>"auth"</tt>.
* The value of this constant is <tt>"javax.security.sasl.qop"</tt>.
*/
public static final String QOP = "javax.security.sasl.qop";
/**
* The name of a property that specifies the cipher strength to use.
* The property contains a comma-separated, ordered list
* of cipher strength values that
* the client or server is willing to support. A strength value is one of
* <ul>
* <li><tt>"low"</tt></li>
* <li><tt>"medium"</tt></li>
* <li><tt>"high"</tt></li>
* </ul>
* The order of the list specifies the preference order of the client or
* server. An implementation should allow configuration of the meaning
* of these values. An application may use the Java Cryptography
* Extension (JCE) with JCE-aware mechanisms to control the selection of
*cipher suites that match the strength values.
* <BR>
* If this property is absent, the default strength is
* <tt>"high,medium,low"</tt>.
* The value of this constant is <tt>"javax.security.sasl.strength"</tt>.
*/
public static final String STRENGTH = "javax.security.sasl.strength";
/**
* The name of a property that specifies whether the
* server must authenticate to the client. The property contains
* <tt>"true"</tt> if the server must
* authenticate the to client; <tt>"false"</tt> otherwise.
* The default is <tt>"false"</tt>.
* <br>The value of this constant is
* <tt>"javax.security.sasl.server.authentication"</tt>.
*/
public static final String SERVER_AUTH =
"javax.security.sasl.server.authentication";
/**
* The name of a property that specifies the maximum size of the receive
* buffer in bytes of <tt>SaslClient</tt>/<tt>SaslServer</tt>.
* The property contains the string representation of an integer.
* <br>If this property is absent, the default size
* is defined by the mechanism.
* <br>The value of this constant is <tt>"javax.security.sasl.maxbuffer"</tt>.
*/
public static final String MAX_BUFFER = "javax.security.sasl.maxbuffer";
/**
* The name of a property that specifies the maximum size of the raw send
* buffer in bytes of <tt>SaslClient</tt>/<tt>SaslServer</tt>.
* The property contains the string representation of an integer.
* The value of this property is negotiated between the client and server
* during the authentication exchange.
* <br>The value of this constant is <tt>"javax.security.sasl.rawsendsize"</tt>.
*/
public static final String RAW_SEND_SIZE = "javax.security.sasl.rawsendsize";
/**
* The name of a property that specifies whether to reuse previously
* authenticated session information. The property contains "true" if the
* mechanism implementation may attempt to reuse previously authenticated
* session information; it contains "false" if the implementation must
* not reuse previously authenticated session information. A setting of
* "true" serves only as a hint: it does not necessarily entail actual
* reuse because reuse might not be possible due to a number of reasons,
* including, but not limited to, lack of mechanism support for reuse,
* expiration of reusable information, and the peer's refusal to support
* reuse.
*
* The property's default value is "false". The value of this constant
* is "javax.security.sasl.reuse".
*
* Note that all other parameters and properties required to create a
* SASL client/server instance must be provided regardless of whether
* this property has been supplied. That is, you cannot supply any less
* information in anticipation of reuse.
*
* Mechanism implementations that support reuse might allow customization
* of its implementation, for factors such as cache size, timeouts, and
* criteria for reuseability. Such customizations are
* implementation-dependent.
*/
public static final String REUSE = "javax.security.sasl.reuse";
/**
* The name of a property that specifies
* whether mechanisms susceptible to simple plain passive attacks (e.g.,
* "PLAIN") are not permitted. The property
* contains <tt>"true"</tt> if such mechanisms are not permitted;
* <tt>"false"</tt> if such mechanisms are permitted.
* The default is <tt>"false"</tt>.
* <br>The value of this constant is
* <tt>"javax.security.sasl.policy.noplaintext"</tt>.
*/
public static final String POLICY_NOPLAINTEXT =
"javax.security.sasl.policy.noplaintext";
/**
* The name of a property that specifies whether
* mechanisms susceptible to active (non-dictionary) attacks
* are not permitted.
* The property contains <tt>"true"</tt>
* if mechanisms susceptible to active attacks
* are not permitted; <tt>"false"</tt> if such mechanisms are permitted.
* The default is <tt>"false"</tt>.
* <br>The value of this constant is
* <tt>"javax.security.sasl.policy.noactive"</tt>.
*/
public static final String POLICY_NOACTIVE =
"javax.security.sasl.policy.noactive";
/**
* The name of a property that specifies whether
* mechanisms susceptible to passive dictionary attacks are not permitted.
* The property contains <tt>"true"</tt>
* if mechanisms susceptible to dictionary attacks are not permitted;
* <tt>"false"</tt> if such mechanisms are permitted.
* The default is <tt>"false"</tt>.
*<br>
* The value of this constant is
* <tt>"javax.security.sasl.policy.nodictionary"</tt>.
*/
public static final String POLICY_NODICTIONARY =
"javax.security.sasl.policy.nodictionary";
/**
* The name of a property that specifies whether mechanisms that accept
* anonymous login are not permitted. The property contains <tt>"true"</tt>
* if mechanisms that accept anonymous login are not permitted;
* <tt>"false"</tt>
* if such mechanisms are permitted. The default is <tt>"false"</tt>.
*<br>
* The value of this constant is
* <tt>"javax.security.sasl.policy.noanonymous"</tt>.
*/
public static final String POLICY_NOANONYMOUS =
"javax.security.sasl.policy.noanonymous";
/**
* The name of a property that specifies whether mechanisms that implement
* forward secrecy between sessions are required. Forward secrecy
* means that breaking into one session will not automatically
* provide information for breaking into future sessions.
* The property
* contains <tt>"true"</tt> if mechanisms that implement forward secrecy
* between sessions are required; <tt>"false"</tt> if such mechanisms
* are not required. The default is <tt>"false"</tt>.
*<br>
* The value of this constant is
* <tt>"javax.security.sasl.policy.forward"</tt>.
*/
public static final String POLICY_FORWARD_SECRECY =
"javax.security.sasl.policy.forward";
/**
* The name of a property that specifies whether
* mechanisms that pass client credentials are required. The property
* contains <tt>"true"</tt> if mechanisms that pass
* client credentials are required; <tt>"false"</tt>
* if such mechanisms are not required. The default is <tt>"false"</tt>.
*<br>
* The value of this constant is
* <tt>"javax.security.sasl.policy.credentials"</tt>.
*/
public static final String POLICY_PASS_CREDENTIALS =
"javax.security.sasl.policy.credentials";
/**
* Creates a <tt>SaslClient</tt> using the parameters supplied.
*
* This method uses the
<a href="http://java.sun.com/j2se/1.4/docs/guide/security/CryptoSpec.html#Provider">JCA Security Provider Framework</a>, described in the
* "Java Cryptography Architecture API Specification & Reference", for
* locating and selecting a <tt>SaslClient</tt> implementation.
*
* First, it
* obtains an ordered list of <tt>SaslClientFactory</tt> instances from
* the registered security providers for the "SaslClientFactory" service
* and the specified SASL mechanism(s). It then invokes
* <tt>createSaslClient()</tt> on each factory instance on the list
* until one produces a non-null <tt>SaslClient</tt> instance. It returns
* the non-null <tt>SaslClient</tt> instance, or null if the search fails
* to produce a non-null <tt>SaslClient</tt> instance.
*<p>
* A security provider for SaslClientFactory registers with the
* JCA Security Provider Framework keys of the form <br>
* <tt>SaslClientFactory.<em>mechanism_name</em></tt>
* <br>
* and values that are class names of implementations of
* <tt>javax.security.sasl.SaslClientFactory</tt>.
*
* For example, a provider that contains a factory class,
* <tt>com.wiz.sasl.digest.ClientFactory</tt>, that supports the
* "DIGEST-MD5" mechanism would register the following entry with the JCA:
* <tt>SaslClientFactory.DIGEST-MD5 com.wiz.sasl.digest.ClientFactory</tt>
*<p>
* See the
* "Java Cryptography Architecture API Specification & Reference"
* for information about how to install and configure security service
* providers.
*
* @param mechanisms The non-null list of mechanism names to try. Each is the
* IANA-registered name of a SASL mechanism. (e.g. "GSSAPI", "CRAM-MD5").
* @param authorizationId The possibly null protocol-dependent
* identification to be used for authorization.
* If null or empty, the server derives an authorization
* ID from the client's authentication credentials.
* When the SASL authentication completes successfully,
* the specified entity is granted access.
*
* @param protocol The non-null string name of the protocol for which
* the authentication is being performed (e.g., "ldap").
*
* @param serverName The non-null fully-qualified host name of the server
* to authenticate to.
*
* @param props The possibly null set of properties used to
* select the SASL mechanism and to configure the authentication
* exchange of the selected mechanism.
* For example, if <tt>props</tt> contains the
* <code>Sasl.POLICY_NOPLAINTEXT</code> property with the value
* <tt>"true"</tt>, then the selected
* SASL mechanism must not be susceptible to simple plain passive attacks.
* In addition to the standard properties declared in this class,
* other, possibly mechanism-specific, properties can be included.
* Properties not relevant to the selected mechanism are ignored.
*
* @param cbh The possibly null callback handler to used by the SASL
* mechanisms to get further information from the application/library
* to complete the authentication. For example, a SASL mechanism might
* require the authentication ID, password and realm from the caller.
* The authentication ID is requested by using a <tt>NameCallback</tt>.
* The password is requested by using a <tt>PasswordCallback</tt>.
* The realm is requested by using a <tt>RealmChoiceCallback</tt> if there is a list
* of realms to choose from, and by using a <tt>RealmCallback</tt> if
* the realm must be entered.
*
*@return A possibly null <tt>SaslClient</tt> created using the parameters
* supplied. If null, cannot find a <tt>SaslClientFactory</tt>
* that will produce one.
*@exception SaslException If cannot create a <tt>SaslClient</tt> because
* of an error.
*/
public static SaslClient createSaslClient(
String[] mechanisms,
String authorizationId,
String protocol,
String serverName,
Map<String,?> props,
CallbackHandler cbh) throws SaslException {
SaslClient mech = null;
SaslClientFactory fac;
String className;
String mechName;
for (int i = 0; i < mechanisms.length; i++) {
if ((mechName=mechanisms[i]) == null) {
throw new NullPointerException(
"Mechanism name cannot be null");
} else if (mechName.length() == 0) {
continue;
}
String mechFilter = "SaslClientFactory." + mechName;
Provider[] provs = Security.getProviders(mechFilter);
for (int j = 0; provs != null && j < provs.length; j++) {
className = provs[j].getProperty(mechFilter);
if (className == null) {
// Case is ignored
continue;
}
fac = (SaslClientFactory) loadFactory(provs[j], className);
if (fac != null) {
mech = fac.createSaslClient(
new String[]{mechanisms[i]}, authorizationId,
protocol, serverName, props, cbh);
if (mech != null) {
return mech;
}
}
}
}
return null;
}
private static Object loadFactory(Provider p, String className)
throws SaslException {
try {
/*
* Load the implementation class with the same class loader
* that was used to load the provider.
* In order to get the class loader of a class, the
* caller's class loader must be the same as or an ancestor of
* the class loader being returned. Otherwise, the caller must
* have "getClassLoader" permission, or a SecurityException
* will be thrown.
*/
ClassLoader cl = p.getClass().getClassLoader();
Class implClass;
implClass = Class.forName(className, true, cl);
return implClass.newInstance();
} catch (ClassNotFoundException e) {
throw new SaslException("Cannot load class " + className, e);
} catch (InstantiationException e) {
throw new SaslException("Cannot instantiate class " + className, e);
} catch (IllegalAccessException e) {
throw new SaslException("Cannot access class " + className, e);
} catch (SecurityException e) {
throw new SaslException("Cannot access class " + className, e);
}
}
/**
* Creates a <tt>SaslServer</tt> for the specified mechanism.
*
* This method uses the
<a href="http://java.sun.com/j2se/1.4/docs/guide/security/CryptoSpec.html#Provider">JCA Security Provider Framework</a>,
* described in the
* "Java Cryptography Architecture API Specification & Reference", for
* locating and selecting a <tt>SaslServer</tt> implementation.
*
* First, it
* obtains an ordered list of <tt>SaslServerFactory</tt> instances from
* the registered security providers for the "SaslServerFactory" service
* and the specified mechanism. It then invokes
* <tt>createSaslServer()</tt> on each factory instance on the list
* until one produces a non-null <tt>SaslServer</tt> instance. It returns
* the non-null <tt>SaslServer</tt> instance, or null if the search fails
* to produce a non-null <tt>SaslServer</tt> instance.
*<p>
* A security provider for SaslServerFactory registers with the
* JCA Security Provider Framework keys of the form <br>
* <tt>SaslServerFactory.<em>mechanism_name</em></tt>
* <br>
* and values that are class names of implementations of
* <tt>javax.security.sasl.SaslServerFactory</tt>.
*
* For example, a provider that contains a factory class,
* <tt>com.wiz.sasl.digest.ServerFactory</tt>, that supports the
* "DIGEST-MD5" mechanism would register the following entry with the JCA:
* <tt>SaslServerFactory.DIGEST-MD5 com.wiz.sasl.digest.ServerFactory</tt>
*<p>
* See the
* "Java Cryptography Architecture API Specification & Reference"
* for information about how to install and configure security
* service providers.
*
* @param mechanism The non-null mechanism name. It must be an
* IANA-registered name of a SASL mechanism. (e.g. "GSSAPI", "CRAM-MD5").
* @param protocol The non-null string name of the protocol for which
* the authentication is being performed (e.g., "ldap").
* @param serverName The non-null fully qualified host name of the server.
* @param props The possibly null set of properties used to
* select the SASL mechanism and to configure the authentication
* exchange of the selected mechanism.
* For example, if <tt>props</tt> contains the
* <code>Sasl.POLICY_NOPLAINTEXT</code> property with the value
* <tt>"true"</tt>, then the selected
* SASL mechanism must not be susceptible to simple plain passive attacks.
* In addition to the standard properties declared in this class,
* other, possibly mechanism-specific, properties can be included.
* Properties not relevant to the selected mechanism are ignored.
*
* @param cbh The possibly null callback handler to used by the SASL
* mechanisms to get further information from the application/library
* to complete the authentication. For example, a SASL mechanism might
* require the authentication ID, password and realm from the caller.
* The authentication ID is requested by using a <tt>NameCallback</tt>.
* The password is requested by using a <tt>PasswordCallback</tt>.
* The realm is requested by using a <tt>RealmChoiceCallback</tt> if there is a list
* of realms to choose from, and by using a <tt>RealmCallback</tt> if
* the realm must be entered.
*
*@return A possibly null <tt>SaslServer</tt> created using the parameters
* supplied. If null, cannot find a <tt>SaslServerFactory</tt>
* that will produce one.
*@exception SaslException If cannot create a <tt>SaslServer</tt> because
* of an error.
**/
public static SaslServer
createSaslServer(String mechanism,
String protocol,
String serverName,
Map<String,?> props,
javax.security.auth.callback.CallbackHandler cbh)
throws SaslException {
SaslServer mech = null;
SaslServerFactory fac;
String className;
if (mechanism == null) {
throw new NullPointerException("Mechanism name cannot be null");
} else if (mechanism.length() == 0) {
return null;
}
String mechFilter = "SaslServerFactory." + mechanism;
Provider[] provs = Security.getProviders(mechFilter);
for (int j = 0; provs != null && j < provs.length; j++) {
className = provs[j].getProperty(mechFilter);
if (className == null) {
throw new SaslException("Provider does not support " +
mechFilter);
}
fac = (SaslServerFactory) loadFactory(provs[j], className);
if (fac != null) {
mech = fac.createSaslServer(
mechanism, protocol, serverName, props, cbh);
if (mech != null) {
return mech;
}
}
}
return null;
}
/**
* Gets an enumeration of known factories for producing <tt>SaslClient</tt>.
* This method uses the same algorithm for locating factories as
* <tt>createSaslClient()</tt>.
* @return A non-null enumeration of known factories for producing
* <tt>SaslClient</tt>.
* @see #createSaslClient
*/
public static Enumeration<SaslClientFactory> getSaslClientFactories() {
Set facs = getFactories("SaslClientFactory");
final Iterator iter = facs.iterator();
return new Enumeration<SaslClientFactory>() {
public boolean hasMoreElements() {
return iter.hasNext();
}
public SaslClientFactory nextElement() {
return (SaslClientFactory)iter.next();
}
};
}
/**
* Gets an enumeration of known factories for producing <tt>SaslServer</tt>.
* This method uses the same algorithm for locating factories as
* <tt>createSaslServer()</tt>.
* @return A non-null enumeration of known factories for producing
* <tt>SaslServer</tt>.
* @see #createSaslServer
*/
public static Enumeration<SaslServerFactory> getSaslServerFactories() {
Set facs = getFactories("SaslServerFactory");
final Iterator iter = facs.iterator();
return new Enumeration<SaslServerFactory>() {
public boolean hasMoreElements() {
return iter.hasNext();
}
public SaslServerFactory nextElement() {
return (SaslServerFactory)iter.next();
}
};
}
private static Set getFactories(String serviceName) {
HashSet result = new HashSet();
if ((serviceName == null) || (serviceName.length() == 0) ||
(serviceName.endsWith("."))) {
return result;
}
Provider[] providers = Security.getProviders();
HashSet classes = new HashSet();
Object fac;
for (int i = 0; i < providers.length; i++) {
classes.clear();
// Check the keys for each provider.
for (Enumeration e = providers[i].keys(); e.hasMoreElements(); ) {
String currentKey = (String)e.nextElement();
if (currentKey.startsWith(serviceName)) {
// We should skip the currentKey if it contains a
// whitespace. The reason is: such an entry in the
// provider property contains attributes for the
// implementation of an algorithm. We are only interested
// in entries which lead to the implementation
// classes.
if (currentKey.indexOf(" ") < 0) {
String className = providers[i].getProperty(currentKey);
if (!classes.contains(className)) {
classes.add(className);
try {
fac = loadFactory(providers[i], className);
if (fac != null) {
result.add(fac);
}
}catch (Exception ignore) {
}
}
}
}
}
}
return Collections.unmodifiableSet(result);
}
}
|
