Status

Current state: "Under DiscussionAccepted"

Discussion thread: here

JIRA: here

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• Channel wrapper for TransportLayer and AuthenticationLayer providing necessary handshake and authentication methods and also read(ByteBuffer buf) , write(ByteBuffer buf), write(ByteBuffer[] buf).
• TransportLayer is an interface for network transportLayer.
• PlainTextTransportLayer provides plain text socket channel methods
• SSLTransportLayer providers provides ssl handshake and read/write methods.
• AuthenticationLayer Authenticator is an interface to providing  providing client/server authentication.
• SaslServerAuthenticationLayer implements AuthenticationLayer, provides  provides authentication methods for server side.
• SaslClientAuthenticationLayer implements AuthenticationLayer, provides client side authentication.
  
  
  
• User: This class will be used to get the remoteUserId and add it to the Session Object (https://issues.apache.org/jira/browse/KAFKA-1683)
• KafkaPrincipalToLocalPlugin: This is a pluggable class with a default implementation which translates a kerberos principal which looks like "testuser/node1.test.com@EXAMPLE.COM" to "testuser". Users can provide a their own customized version of PrincipalToLocalPlugin.
• AuthUtils: This class will consists of any utilities needed for SASL and other auth related methods.
• KerberosLoginFactory:  It will use jaas config to login and generates a subject. 
• Protocol accepts the protocol type (PLAINTEXT, SSL )SecurityConfig , a config file for provider SecurityProtocol, PLAINTEXT+SASL,  SSL config and +SASL mechanisms.
  
• BlockingChannel interface changes as it accepts the Protocol to create appropriate channels.

Proposed Changes

we will be using SASL to provide authentication and SSL to provider encryption in connection oriented protocols. 

As part of SASL implementation we will be using JAAS config to read kerberos ticket and authenticate. More info on JAAS Config

http://docs.oracle.com/javase/7/docs/technotes/guides/security/jaas/JAASRefGuide.html

Proposed JAAS Login config file will look like this.

Users needs to pass -Djava.security.auth.login.config=kafka_jaas.conf as part of JVM params .

• )
  • PLAINTEXT (non-authenticated, non-encrypted)
    • This channel will provide exact behavior for communication channels as previous releases
      
  • SSL
    •  SSL  implementation. Authenticated principal in the session will be from the certificate presented or the peer host. 
  • SASL+PLAINTEXT
    • SASL authentication will be used over plaintext channel. Once the sasl authentication established between client and server . Session will have client’s principal as authenticated user. There won’t be any wire encryption in this case as all the channel communication will be over plain text .
  • SASL+SSL

    • SSL will be established initially and  SASL authentication will be done over SSL. Once SASL authentication is established users principal will be used as authenticated user .  This option is useful if users want to use SASL authentication ( for example kerberos ) with wire encryption.

        

       

• SecurityConfig , a config file for provider SecurityProtocol,  SSL config and SASL mechanisms.
  
• BlockingChannel interface changes as it accepts the Protocol to create appropriate channels.
  
  

Proposed Changes

we will be using SASL to provide authentication and SSL to provider encryption in connection oriented protocols. 

As part of SASL implementation we will be using JAAS config to read kerberos ticket and authenticate. More info on JAAS Config

http://docs.oracle.com/javase/7/docs/technotes/guides/security/jaas/JAASRefGuide.html

Proposed JAAS Login config file will look like this.

Users needs to pass -Djava.security.auth.login.config=kafka_jaas.conf as part of JVM params .

This JAAS file along with Login.java can be used to login into LDAP or KERBEROS etc.. 

Here are some details on LdapLoginModule for JAAS https://docs.oracle.com/javase/8/docs/jre/api/security/jaas/spec/com/sun/security/auth/module/LdapLoginModule.html 

KafkaServer {
com.sun.security.

KafkaServer {
com.sun.security.auth.module.Krb5LoginModule required
useKeyTab=true
keyTab="/keytabs/kafka.keytab"
storeKey=true
useTicketCache=false
serviceName="kafka" // this will be used to connect to other brokers for replica management and also controller requests. This should be set to whatever principal that kafka brokers are running.
principal="kafka/_HOST@EXAMPLE.COM";
};
Client {
com.sun.security.auth.module.Krb5LoginModule required
useKeyTab=true
keyTab="/keytabs/kafka.keytab"
storeKey=true
useTicketCache=false
serviceName="zookeeper"
principal="kafka@EXAMPLE.COM";
}


KafkaServer will be used to authenticate Kafka broker against kerberos
and Client section will be used for zkClient to access kerberos enabled zookeeper cluster.

KafkaClient {
com.sun.security.auth.module.Krb5LoginModule required
useKeyTab=true
keyTab="/keytabs/kafkaclientkafka.keytab"
storeKey=true
useTicketCache=false
serviceName="kafka"
principal="kafkaproducer/_HOST@EXAMPLE.COM";
};
 
The above config is for any client ( producer, consumer) connecting to kerberos enabled Kafka cluster.
Here serviceName must match the principal name used under KafkaServer.
 

Channel

 // this will be used to connect to other brokers for replica management and also controller requests. This should be set to whatever principal that kafka brokers are running.
principal="kafka/_HOST@EXAMPLE.COM";
};
Client {
com.sun.security.auth.module.Krb5LoginModule required
useKeyTab=true
keyTab="/keytabs/kafka.keytab"
storeKey=true
useTicketCache=false
serviceName="zookeeper"
principal="kafka@EXAMPLE.COM";
}


KafkaServer will be used to authenticate Kafka broker against kerberos
and Client section will be used for zkClient to access kerberos enabled zookeeper cluster.

KafkaClient {
com.sun.security.auth.module.Krb5LoginModule required
useKeyTab=true
keyTab="/keytabs/kafkaclient.keytab"
storeKey=true
useTicketCache=false
serviceName="kafka"
principal="kafkaproducer/_HOST@EXAMPLE.COM";
};
 
The above config is for any client ( producer, consumer) connecting to kerberos enabled Kafka cluster.
Here serviceName must match the principal name used under KafkaServer.
 

Channel

package org.apache.kafka.common.network;
 
public class Channel implements ScatteringByteChannel, GatheringByteChannel {
   private TransportLayer transportLayer;
   private Authenticator authenticator;

   public Channel(TransportLayer transportLayer, Authenticator authenticator) throws IOException 
  

package org.apache.kafka.common.network;
 
public class Channel implements ScatteringByteChannel, GatheringByteChannel {
   private TransportLayer transportLayer;
   private Authenticator authenticator;

   public Channel(TransportLayer transportLayer, Authenticator authenticator) throws IOException 
  
   /**
    * returns user principal for the session
    * Incase of PLAINTEXT and No Authentication returns ANONYMOUS as the userPrincipal
    * If SSL used without any SASL Authentication returns SSLSession.peerPrincipal
    */
    public UserPrincipal userPrincipal() {
       return authenticator.userPrincipal();
    }

    /**
    * * starts transportLayer handshakereturns user principal for the session
     * If transportLayer handshake finishes, than initiates AuthenticationLayer.authenticate
 Incase of PLAINTEXT and No Authentication returns ANONYMOUS as the userPrincipal
    * @returnsIf 0SSL ifused handshakewithout andany authenticationSASL finishes otherwiseAuthentication returns appropriate SelctionKeySSLSession.OPpeerPrincipal
     */
    public intUserPrincipal connectuserPrincipal(boolean) read,{
 boolean write) throws IOException 
  return authenticator.userPrincipal();
    }

    /**
     * starts transportLayer handshake
     */
 If transportLayer handshake publicfinishes, voidthan blockingConnect(long timeout) throws IOException
  
initiates AuthenticationLayer.authenticate
     * @Override
@returns 0 if handshake publicand intauthentication write(ByteBuffer src) throws IOException
 
finishes otherwise returns appropriate SelctionKey.OP
     @Override*/
    public int read(ByteBuffer dstconnect(boolean read, boolean write) throws IOException 
     
    /**
  returns the socketChannel */ 
    public SocketChannel socketChannel();
 
	@Override
 */
    public longvoid writeblockingConnect(ByteBuffer[]long srcstimeout) throws IOException 
     
    @Override
    public longint write(ByteBuffer[] srcs, int offset, int length src) throws IOException
 
    @Override
    public int read(ByteBuffer dst) throws IOException
 
    /* returns the socketChannel */
    public SocketChannel socketChannel();
 
	@Override
    public long readwrite(ByteBuffer[] dstssrcs) throws IOException 
   
    @Override
    public long readwrite(ByteBuffer[] dstssrcs, int offset, int length) throws IOException

    @Override
    public booleanint finishConnectread(ByteBuffer dst) throws IOException

    @Override
    public DataInputStreamlong getInputStreamread(ByteBuffer[] dsts) throws IOException 

    @Override
    public DataOutputStreamlong getOutputStream(read(ByteBuffer[] dsts, int offset, int length) throws IOException

    public voidboolean closefinishConnect() throws IOException
    
 }    public DataInputStream getInputStream() throws IOException

    public DataOutputStream getOutputStream() throws IOException

    public void close() throws IOException
    
 }

TransportLayer

public interface TransportLayer {

    /**
     * Closes this channel
     *
     * @throws IOException If and I/O error occurs
     */
    void close() throws IOException;


    /**
     * Tells wheather or not this channel is open.
     */
    boolean isOpen();

    /**
     * Writes a sequence of bytes to this channel from the given buffer.
     */
    int write(ByteBuffer src) throws IOException;

    long write(ByteBuffer[] srcs) throws IOException;

    long write(ByteBuffer[] srcs, int offset, int length) throws IOException;

    int read(ByteBuffer dst) throws IOException;

    long read(ByteBuffer[] dsts) throws IOException;

    long read(ByteBuffer[] dsts, int offset, int length) throws IOException;

    boolean isReady();

    boolean finishConnect() throws IOException;

    SocketChannel socketChannel();

    /**
     * Performs SSL handshake hence is a no-op for the non-secure
     * implementation
     * @param read Unused in non-secure implementation
     * @param write Unused in non-secure implementation
     * @return Always return 0
     * @throws IOException
    */
    int handshake(boolean read, boolean write) throws IOException;

    DataInputStream inStream() throws IOException;

    DataOutputStream outStream() throws IOException;

    boolean flush(ByteBuffer buffer) throws IOException;

    Principal getPeerPrincipal();
}

PlainTextTransportLayer

public class PlainTextTransportLayer implements TransportLayer {
   public PlainTextTransportLayer(SocketChannel socketChannel) throws IOException
}  
 

SSLTransportLayer

public class SSLTransportLayer implements TransportLayer {
	public SSLTransportLayer(SocketChannel socketChannel, SSLEngine sslEngine) throws IOException 
}  
 

...

 Authenticator

public interface Authenticator {

    /**
     * Closes any resources
     *
     * @throws IOException if any I/O error occurs
     */
    void close() throws IOException;

    /**
     *
     * @throws IOException
     */
    void init() throws IOException;

    /**
     * Returns UserPrincipal after authentication is established
     */
    UserPrincipal userPrincipal();


    /**
     * Does authentication in non-blocking way and returns SelectionKey.OP if further communication needed
     */
    int authenticate(boolean read, boolean write) throws IOException;

    /**
     * returns true if authentication is complete otherwise returns false;
     */

    boolean isComplete();

}
 
 

...

DefaultAuthenticator

public class DefaultAuthenticator implements Authenticator {

    TransportLayer transportLayer;

    public DefaultAuthenticator(TransportLayer transportLayer) {
        this.transportLayer = transportLayer;
    }

    public void init() {}

    public int authenticate(boolean read, boolean write) throws IOException {
        return 0;
    }

    /** returns peer host incase of SSL */
    public UserPrincipal userPrincipal() {
        return new UserPrincipal(transportLayer.getPeerPrincipal().toString());
    }

    public void close() throws IOException {}

    public boolean isComplete() {
        return true;
    }
}
  
 

...

SaslServerAuthenticator

public class AuthUtilsSaslServerAuthenticator implements Authenticator {

   /**
 public SaslServerAuthenticator(final Subject subject, *TransportLayer ConstructtransportLayer) a{
 JAAS configuration object per kafka jaas configuration file
     * @param storm_conf Storm configuration
     * @return JAAS configuration object
     */
    public static Configuration getConfiguration(String jaasConfigFilePath)
 
    public static String getJaasConfig(String loginContextName, String key) throws IOException
 
    public static String getDefaultRealm()
 
}
 
 

Login

package org.apache.kafka.common.security.kerberos;
 
public class Login {
private volatile Subject subject = null;
 
//logs in based on jaas conf and starts a thread to renew it .
public Login(final String loginContextName)
            throws LoginException 
 
// returns generated subject after the login.
public Subject getSubject() 


}
 

KerberosLoginManager

package kafka.common
 
object KerberosLoginManager {
   var kerberosLogin: Login 
 
   //does kerberos login and generates the subject
   def init()
 
   // returns kerberosLogin.getSubject()
   def subject()
 
   def shutdown()
   
}

...

KafkaClient

1) KafkaClient picks the principal it wants to use by looking at KafkaClient jaas config (example above).

2) Authenticates against KDC (kerberos) using the KafkaClient principal.

3) KafkaClient constructs the service principal name based on the jaas config serviceName

4) KafkaClient initiates challenge/response with KafkaBroker along with KafkaClient principal and service principal . Depending on the KafkaBroker response these challenge/response might continue until it receives COMPLETE from the KafkaBroker.

KafkaBroker

1) KafkaBroker will accept the connection and accepts the client and service principal

2) checks if the service principal is same as the one KafkaBroker running with.

3) KafkaBroker accepts/rejects the clients token

4) Returns the response to the client if its authenticated or not.

 }
}
  
 

SaslClientAuthenticator

public class SaslServerAuthenticator implements Authenticator {
   public SaslServerAuthenticator(final Subject subject, TransportLayer transportLayer) {
   }
}
  
 

Callbacks  for Login , SaslServer, SaslClient

    Callbacks for the above modules will help in grabbing the users authentication information.

AuthUtils

public class AuthUtils {
   /**
     * Construct a JAAS configuration object per kafka jaas configuration file
     * @param storm_conf Storm configuration
     * @return JAAS configuration object
     */
    public static Configuration getConfiguration(String jaasConfigFilePath)
 
    public static String getJaasConfig(String loginContextName, String key) throws IOException
 
    public static String getDefaultRealm()
 
}
 
 

Login

package org.apache.kafka.common.security.kerberos;
 
public class Login {
private volatile Subject subject = null;
 
//logs in based on jaas conf and starts a thread to renew it .
public Login(final String loginContextName)
            throws LoginException 
 
// returns generated subject after the login.
public Subject getSubject() 


}
 

KerberosLoginManager

package kafka.common
 
object KerberosLoginManager {
   var kerberosLogin: Login 
 
   //does kerberos login and generates the subject
   def init()
 
   // returns kerberosLogin.getSubject()
   def subject()
 
   def shutdown()
   
}

SASL Authentication exchange

KafkaClient

1) KafkaClient picks the principal it wants to use by looking at KafkaClient jaas config (example above).

2) Authenticates against KDC (kerberos) using the KafkaClient principal.

3) KafkaClient constructs the service principal name based on the jaas config serviceName

4) KafkaClient initiates challenge/response with KafkaBroker along with KafkaClient principal and service principal . Depending on the KafkaBroker response these challenge/response might continue until it receives COMPLETE from the KafkaBroker.

KafkaBroker

1) KafkaBroker will accept the connection and accepts the client and service principal

2) checks if the service principal is same as the one KafkaBroker running with.

3) KafkaBroker accepts/rejects the clients token

4) Returns the response to the client if its authenticated or not.

5) Once client is authenticated they can send Kafka requests.

Security Config

SecurityConfig will be shared across clients and brokers. If not provided communication channels fall back to PLAINTEXT . Here are proposed configs

sasl.authentication.mechanism (KERBEROS will be supported for revision1) 
ssl.protocol
ssl.cipher.suites
ssl.enabled.protocols
ssl.keystore.type
ssl.keystore.location
ssl.keystore.password
ssl.key.password
ssl.truststore.type
ssl.truststore.location
ssl.truststore.password
ssl.client.require.cert
ssl.keymanager.algorithm
ssl.trustmanager.algorithm
 

 5) Once client is authenticated they can send Kafka requests.

Compatibility, Deprecation, and Migration Plan

...

1) Users should be configuring -Djava.security.auth.login.config=jass_file.conf . after setting kerberosauthentication.enable to true in server and also in clients. Any objections on this approach?

...

3) Similarly Producer and Consumer does KerberosLoginManager.init() with "KafkaClient" section  if kerberosauthentication.enable set to true and also passes Protocol to BlockingChannel.  Any alternatives or objections on this approach?

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