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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.InvalidParameterException;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;
import java.security.Provider.Service;
import java.security.Security;
/**
* A static class for creating SASL clients and servers.
*
* This class defines the policy of how to locate, load, and instantiate
* SASL clients and servers.
*
* For example, an application or library gets a SASL client by doing
* something like:
*
*
* @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
*
*
{@code "auth"} - authentication only
*
{@code "auth-int"} - authentication plus integrity protection
*
{@code "auth-conf"} - authentication plus integrity and confidentiality
* protection
*
*
* The order of the list specifies the preference order of the client or
* server. If this property is absent, the default qop is {@code "auth"}.
* The value of this constant is {@code "javax.security.sasl.qop"}.
*/
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
*
*
{@code "low"}
*
{@code "medium"}
*
{@code "high"}
*
* 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.
*
* If this property is absent, the default strength is
* {@code "high,medium,low"}.
* The value of this constant is {@code "javax.security.sasl.strength"}.
*/
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
* {@code "true"} if the server must
* authenticate the to client; {@code "false"} otherwise.
* The default is {@code "false"}.
* The value of this constant is
* {@code "javax.security.sasl.server.authentication"}.
*/
public static final String SERVER_AUTH =
"javax.security.sasl.server.authentication";
/**
* The name of a property that specifies the bound server name for
* an unbound server. A server is created as an unbound server by setting
* the {@code serverName} argument in {@link #createSaslServer} as null.
* The property contains the bound host name after the authentication
* exchange has completed. It is only available on the server side.
* The value of this constant is
* {@code "javax.security.sasl.bound.server.name"}.
*/
public static final String BOUND_SERVER_NAME =
"javax.security.sasl.bound.server.name";
/**
* The name of a property that specifies the maximum size of the receive
* buffer in bytes of {@code SaslClient}/{@code SaslServer}.
* The property contains the string representation of an integer.
* If this property is absent, the default size
* is defined by the mechanism.
* The value of this constant is {@code "javax.security.sasl.maxbuffer"}.
*/
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 {@code SaslClient}/{@code SaslServer}.
* 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.
* The value of this constant is {@code "javax.security.sasl.rawsendsize"}.
*/
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 reusability. 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 {@code "true"} if such mechanisms are not permitted;
* {@code "false"} if such mechanisms are permitted.
* The default is {@code "false"}.
* The value of this constant is
* {@code "javax.security.sasl.policy.noplaintext"}.
*/
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 {@code "true"}
* if mechanisms susceptible to active attacks
* are not permitted; {@code "false"} if such mechanisms are permitted.
* The default is {@code "false"}.
* The value of this constant is
* {@code "javax.security.sasl.policy.noactive"}.
*/
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 {@code "true"}
* if mechanisms susceptible to dictionary attacks are not permitted;
* {@code "false"} if such mechanisms are permitted.
* The default is {@code "false"}.
*
* The value of this constant is
* {@code "javax.security.sasl.policy.nodictionary"}.
*/
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 {@code "true"}
* if mechanisms that accept anonymous login are not permitted;
* {@code "false"}
* if such mechanisms are permitted. The default is {@code "false"}.
*
* The value of this constant is
* {@code "javax.security.sasl.policy.noanonymous"}.
*/
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 {@code "true"} if mechanisms that implement forward secrecy
* between sessions are required; {@code "false"} if such mechanisms
* are not required. The default is {@code "false"}.
*
* The value of this constant is
* {@code "javax.security.sasl.policy.forward"}.
*/
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 {@code "true"} if mechanisms that pass
* client credentials are required; {@code "false"}
* if such mechanisms are not required. The default is {@code "false"}.
*
* The value of this constant is
* {@code "javax.security.sasl.policy.credentials"}.
*/
public static final String POLICY_PASS_CREDENTIALS =
"javax.security.sasl.policy.credentials";
/**
* The name of a property that specifies the credentials to use.
* The property contains a mechanism-specific Java credential object.
* Mechanism implementations may examine the value of this property
* to determine whether it is a class that they support.
* The property may be used to supply credentials to a mechanism that
* supports delegated authentication.
*
* The value of this constant is
* {@code "javax.security.sasl.credentials"}.
*/
public static final String CREDENTIALS = "javax.security.sasl.credentials";
/**
* Creates a {@code SaslClient} using the parameters supplied.
*
* This method uses the
JCA Security Provider Framework, described in the
* "Java Cryptography Architecture API Specification & Reference", for
* locating and selecting a {@code SaslClient} implementation.
*
* First, it
* obtains an ordered list of {@code SaslClientFactory} instances from
* the registered security providers for the "SaslClientFactory" service
* and the specified SASL mechanism(s). It then invokes
* {@code createSaslClient()} on each factory instance on the list
* until one produces a non-null {@code SaslClient} instance. It returns
* the non-null {@code SaslClient} instance, or null if the search fails
* to produce a non-null {@code SaslClient} instance.
*
* A security provider for SaslClientFactory registers with the
* JCA Security Provider Framework keys of the form
* {@code SaslClientFactory.}{@code mechanism_name}
*
* and values that are class names of implementations of
* {@code javax.security.sasl.SaslClientFactory}.
*
* For example, a provider that contains a factory class,
* {@code com.wiz.sasl.digest.ClientFactory}, that supports the
* "DIGEST-MD5" mechanism would register the following entry with the JCA:
* {@code SaslClientFactory.DIGEST-MD5 com.wiz.sasl.digest.ClientFactory}
*
* 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 {@code props} contains the
* {@code Sasl.POLICY_NOPLAINTEXT} property with the value
* {@code "true"}, 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,
* including any map entries with non-String keys.
*
* @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 {@code NameCallback}.
* The password is requested by using a {@code PasswordCallback}.
* The realm is requested by using a {@code RealmChoiceCallback} if there is a list
* of realms to choose from, and by using a {@code RealmCallback} if
* the realm must be entered.
*
*@return A possibly null {@code SaslClient} created using the parameters
* supplied. If null, cannot find a {@code SaslClientFactory}
* that will produce one.
*@exception SaslException If cannot create a {@code SaslClient} because
* of an error.
*/
public static SaslClient createSaslClient(
String[] mechanisms,
String authorizationId,
String protocol,
String serverName,
Map props,
CallbackHandler cbh) throws SaslException {
SaslClient mech = null;
SaslClientFactory fac;
Service service;
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 type = "SaslClientFactory";
Provider[] provs = Security.getProviders(type + "." + mechName);
if (provs != null) {
for (Provider p : provs) {
service = p.getService(type, mechName);
if (service == null) {
// no such service exists
continue;
}
fac = (SaslClientFactory) loadFactory(service);
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(Service service)
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.
*/
return service.newInstance(null);
} catch (InvalidParameterException | NoSuchAlgorithmException e) {
throw new SaslException("Cannot instantiate service " + service, e);
}
}
/**
* Creates a {@code SaslServer} for the specified mechanism.
*
* This method uses the
JCA Security Provider Framework,
* described in the
* "Java Cryptography Architecture API Specification & Reference", for
* locating and selecting a {@code SaslServer} implementation.
*
* First, it
* obtains an ordered list of {@code SaslServerFactory} instances from
* the registered security providers for the "SaslServerFactory" service
* and the specified mechanism. It then invokes
* {@code createSaslServer()} on each factory instance on the list
* until one produces a non-null {@code SaslServer} instance. It returns
* the non-null {@code SaslServer} instance, or null if the search fails
* to produce a non-null {@code SaslServer} instance.
*
* A security provider for SaslServerFactory registers with the
* JCA Security Provider Framework keys of the form
* {@code SaslServerFactory.}{@code mechanism_name}
*
* and values that are class names of implementations of
* {@code javax.security.sasl.SaslServerFactory}.
*
* For example, a provider that contains a factory class,
* {@code com.wiz.sasl.digest.ServerFactory}, that supports the
* "DIGEST-MD5" mechanism would register the following entry with the JCA:
* {@code SaslServerFactory.DIGEST-MD5 com.wiz.sasl.digest.ServerFactory}
*
* 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 fully qualified host name of the server, or null
* if the server is not bound to any specific host name. If the mechanism
* does not allow an unbound server, a {@code SaslException} will
* be thrown.
* @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 {@code props} contains the
* {@code Sasl.POLICY_NOPLAINTEXT} property with the value
* {@code "true"}, 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,
* including any map entries with non-String keys.
*
* @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 {@code NameCallback}.
* The password is requested by using a {@code PasswordCallback}.
* The realm is requested by using a {@code RealmChoiceCallback} if there is a list
* of realms to choose from, and by using a {@code RealmCallback} if
* the realm must be entered.
*
*@return A possibly null {@code SaslServer} created using the parameters
* supplied. If null, cannot find a {@code SaslServerFactory}
* that will produce one.
*@exception SaslException If cannot create a {@code SaslServer} because
* of an error.
**/
public static SaslServer
createSaslServer(String mechanism,
String protocol,
String serverName,
Map props,
javax.security.auth.callback.CallbackHandler cbh)
throws SaslException {
SaslServer mech = null;
SaslServerFactory fac;
Service service;
if (mechanism == null) {
throw new NullPointerException("Mechanism name cannot be null");
} else if (mechanism.length() == 0) {
return null;
}
String type = "SaslServerFactory";
Provider[] provs = Security.getProviders(type + "." + mechanism);
if (provs != null) {
for (Provider p : provs) {
service = p.getService(type, mechanism);
if (service == null) {
throw new SaslException("Provider does not support " +
mechanism + " " + type);
}
fac = (SaslServerFactory) loadFactory(service);
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 {@code SaslClient}.
* This method uses the same algorithm for locating factories as
* {@code createSaslClient()}.
* @return A non-null enumeration of known factories for producing
* {@code SaslClient}.
* @see #createSaslClient
*/
public static Enumeration getSaslClientFactories() {
Set