Authentication.phpclass

<?php
/**************************************************************************************************************

    NAME
        Ssh.phpclass

    DESCRIPTION
        Ssh protocol encapsulation classes.

    AUTHOR
        Christian Vigh, 01/2015.

    HISTORY
    [Version : 1.0]    [Date : 2015/05/17]     [Author : CV]
        Initial version.

 **************************************************************************************************************/

/*==============================================================================================================

    SshAuthentication class -
        Base class for all other authentication classes.

  ==============================================================================================================*/
abstract class  SshAuthentication		// extends  Object
   {
	// Constants for the GetInstance() method
	const		SSH_AUTHENTICATION_AGENT		=  1 ;
	const		SSH_AUTHENTICATION_HOSTBASED_FILE	=  2 ;
	const		SSH_AUTHENTICATION_NONE			=  3 ;
	const		SSH_AUTHENTICATION_PASSWORD		=  4 ;
	const		SSH_AUTHENTICATION_PUBKEY_FILE		=  5 ;
	
	// Parent session
	public		$Session ;
	// All derived classes have a username in common
	public		$Username ;
	// Indicates if an authentication has been established
	public		$Authenticated				=  false ;
	
	
	/*==============================================================================================================
	
	    Constructor -
	        Builds an SshAuthentication object. A Session object must be provided so that session data remains
		accessible from authentication classes.
	
	  ==============================================================================================================*/
	public function  __construct ( $session, $username )
	   {
		//parent::__construct ( ) ;
		
		$this -> Username	=  $username ;
		$this -> Session	=  $session ;
	    }
	
	
	/*==============================================================================================================
	
	    Authenticate -
	        Performs the authentication. To be implemented by derived classes.
	
	  ==============================================================================================================*/
	public abstract function  Authenticate ( ) ;
	
	
	/*==============================================================================================================
	
	    GetInstance -
	        Returns an authentication object of the specified type. For the purists only ; those who prefer 
	 	performance will directly call the constructor of the class they want.
	 	Note that specific authentication class constructor arguments MUST be specified after the $session
	 	parameter.
	
	  ==============================================================================================================*/
	public static function  GetInstance ( $auth_type, $session )
	   {
		$argv	=  func_get_args ( ) ;
		array_shift ( $argv ) ;
		
		switch ( $auth_type )
		   {
			case	self::SSH_AUTHENTICATION_AGENT :
				$class	=  'SshAgentAuthentication' ;
				break ;
				
			case	self::SSH_AUTHENTICATION_HOSTBASED_FILE :
				$class	=  'SshHostBasedAuthentication' ;
				break ;
				
			case	self::SSH_AUTHENTICATION_NONE :
				$class	=  'SshAuthenticationNone' ;
				break ;
				
			case	self::SSH_AUTHENTICATION_PASSWORD :
				$class	=  'SshPasswordAuthentication' ;
				break ;
				
			case	self::SSH_AUTHENTICATION_PUBKEY_FILE :
				$class	=  'SshPublicKeyAuthentication' ;
				break ;
				
			default :
				error ( \InvalidArgumentException ( "Invalid value $auth_type for the \$auth_type parameter" ) ) ;
		    }
		
		$object		=  call_user_func_array ( [ $class, '__construct' ], $argv ) ;
		
		return ( $object ) ;
	    }
	
	
	/*==============================================================================================================
	
	    GetSession -
	        Ensures that the Session object is connected.
	
	  ==============================================================================================================*/
	protected function  GetSession ( )
	   {
		if  ( $this -> Session )
		   {
			$connection	=  $this -> Session -> Connection ;
				
			if  ( $connection -> IsConnected ( ) )
				return  ( $connection -> GetResource ( ) ) ;
		    }
		
		error ( new SshSessionException ( get_class ( ) . ' : Cannot authenticate, no connection established.' ) ) ;
	    }
    }


/*==============================================================================================================

    SshAgentAuthentication -
        Authentication using ssh agent.

  ==============================================================================================================*/

class  SshAgentAuthentication		extends  SshAuthentication
   {
	public function  __construct ( $session, $username )
	   {
		parent::__construct ( $session, $username ) ;
	    }
	
	
	public function  Authenticate ( )
	   {
		$status			=  ssh2_auth_agent ( $this -> GetSession ( ), $this -> Username ) ;
		$this -> Authenticated	=  ( $status  ===  true ) ;

		return ( $status ) ;
	    }
    }


/*==============================================================================================================

    SshAuthenticationNone -
        Tries a "none" authentication. Returns true if the "none" method is supported, or an array of supported
	methods otherwise.

  ==============================================================================================================*/
class  SshAuthenticationNone		extends  SshAuthentication
   {
	public function  __construct ( $session, $username )
	   {
		parent::__construct ( $session, $username ) ;
	    }
	
	
	public function  Authenticate ( )
	   {
		$status			=  ssh2_auth_none ( $this -> GetSession ( ), $this -> Username ) ;
		$this -> Authenticated	=  false ;

		return ( $status ) ;
	    }
    }


/*==============================================================================================================

    SshPasswordAuthentication -
        Authentication with username/password.

  ==============================================================================================================*/
class  SshPasswordAuthentication		extends  SshAuthentication
   {
	public	$Password ;
	
	
	public function  __construct ( $session, $username, $password )
	   {
		parent::__construct ( $session, $username ) ;
		
		$this -> Password	=  $password ;
	    }
	
	
	public function  Authenticate ( )
	   {
		$status			=  ssh2_auth_password ( $this -> GetSession ( ), $this -> Username, $this -> Password ) ;
		$this -> Authenticated	=  ( $status  ===  true ) ;

		return ( $status ) ;
	    }
    }


/*==============================================================================================================

    SshKeyBasedAuthentication class -
        Base class for the SshHostBasedAuthentication and SshPublicKeyAuthentication classes.

  ==============================================================================================================*/
abstract class  SshKeyBasedAuthentication		extends  SshAuthentication
   {
	public		$PublicKeyFile ;
	public		$PrivateKeyFile ;
	public		$PassPhrase ;
	
	
	public function  __construct ( $session, $username, $public_key_file, $private_key_file, $passphrase = null )
	   {
		parent::__construct ( $session, $username ) ;

		if  ( ! file_exists ( $public_key_file ) )
			error ( new \Exception ( "Public key file \"$public_key_file\" not found" ) ) ;
		
		if  ( ! file_exists ( $private_key_file ) )
			error ( new \Exception ( "Private key file \"$private_key_file\" not found" ) ) ;
				
		$this -> PublicKeyFile	=  realpath ( $public_key_file ) ;
		$this -> PrivateKeyFile	=  realpath ( $private_key_file ) ;
		$this -> PassPhrase	=  $passphrase ;
	    }
    }


/*==============================================================================================================

    SshPublicKeyAuthentication -
        Authentication using a public key.

  ==============================================================================================================*/
class  SshPublicKeyAuthentication		extends  SshKeyBasedAuthentication
   {
	public function  __construct ( $session, $username, $public_key_file, $private_key_file, $passphrase = null )
	   {
		parent::__construct ( $session, $username, $public_key_file, $private_key_file, $passphrase ) ;
	    }
	
	
	// FIX: ssh2_auth_pubkey_file() always return the following error :
	//	ssh2_auth_pubkey_file(): Authentication failed for root using public key: Callback returned error.
	public function  Authenticate ( )
	   {
		$status			=  ssh2_auth_pubkey_file ( $this -> GetSession ( ), $this -> Username, 
							$this -> PublicKeyFile, $this -> PrivateKeyFile, $this -> PassPhrase ) ;
		$this -> Authenticated	=  ( $status  ===  true ) ;

		return ( $status ) ;
	    }
    }


/*==============================================================================================================

    SshHostBasedAuthentication -
        Authentication through an external host.

  ==============================================================================================================*/
class  SshHostBasedAuthentication		extends  SshKeyBasedAuthentication
   {
	public		$Host ;
	
	
	public function  __construct ( $session, $username, $host, $public_key_file, $private_key_file, $passphrase = null )
	   {
		parent::__construct ( $session, $username, $public_key_file, $private_key_file, $passphrase ) ;
		
		$this -> Host	=  $host ;
	    }
	
	
	public function  Authenticate ( )
	   {
		$status			=  ssh2_auth_hostbased_file ( $this -> GetSession ( ), $this -> Username, $this -> Host,
							$this -> PublicKeyFile, $this -> PrivateKeyFile, $this -> PassPhrase ) ;
		$this -> Authenticated	=  ( $status  ===  true ) ;

		
		return ( $status ) ;
	    }
    }