<?php

if ( getConfig('yubikey_enable', '1') != '1' )
		return true;

// hook into auth
$plugins->attachHook('login_process_userdata_json', 'return yubikey_auth_hook_json($userinfo, $req["level"], @$req["remember"]);');
// hook into special page init
$plugins->attachHook('session_started', 'yubikey_add_special_pages();');
// session key security
$plugins->attachHook('session_key_calc', 'yubikey_sk_calc($user_id, $key_pieces, $sk_mode);');

function yubikey_auth_hook_json(&$userdata, $level, $remember)
{
	global $db, $session, $paths, $template, $plugins; // Common objects
	global $lang;
	
	$do_validate_otp = false;
	$do_validate_user = false;
	$do_validate_pass = false;
	
	$user_flag = ( $level >= USER_LEVEL_CHPREF ) ? YK_SEC_ELEV_USERNAME : YK_SEC_NORMAL_USERNAME;
	$pass_flag = ( $level >= USER_LEVEL_CHPREF ) ? YK_SEC_ELEV_PASSWORD : YK_SEC_NORMAL_PASSWORD;
	
	$auth_log_prefix = ( $level >= USER_LEVEL_CHPREF ) ? 'admin_' : '';
	
	// Sort of a hack: if the password looks like an OTP and the OTP field is empty, use the password as the OTP
	if ( empty($userdata['yubikey_otp']) && preg_match('/^[cbdefghijklnrtuv]{44}$/', $userdata['password'] ) )
	{
		$userdata['yubikey_otp'] = $userdata['password'];
	}
	
	// Lockouts removed from here - they're done during preprocessing now.
	
	if ( !empty($userdata['username']) )
	{
		// get flags
		$q = $db->sql_query('SELECT user_id, user_yubikey_flags FROM ' . table_prefix . "users WHERE " . ENANO_SQLFUNC_LOWERCASE . "(username) = '" . $db->escape(strtolower($userdata['username'])) . "';");
		if ( !$q )
			$db->die_json();
		
		if ( $db->numrows() < 1 )
		{
			// Username not found - let the main login function handle it
			$db->free_result();
			return null;
		}
		list($user_id, $flags) = $db->fetchrow_num();
		$flags = intval($flags);
		// At the point the username is validated.
		$do_validate_user = false;
		$do_validate_pass = $flags & $pass_flag;
		if ( empty($userdata['yubikey_otp']) )
		{
			// no OTP was provided
			// make sure the user has allowed logging in with no OTP
			if ( !($flags & YK_SEC_ALLOW_NO_OTP) )
			{
				// We also might have no Yubikeys enrolled.
				$q = $db->sql_query('SELECT 1 FROM ' . table_prefix . "yubikey WHERE user_id = $user_id;");
				if ( !$q )
					$db->die_json();
				
				if ( $db->numrows() > 0 )
				{
					// Yep at least one key is enrolled.
					// I don't think these should be logged because they'll usually just be innocent mistakes.
					$db->free_result();
					return array(
							'mode' => 'error',
							'error' => 'yubiauth_err_must_have_otp'
						);
				}
				// Nope, no keys enrolled, user hasn't enabled Yubikey support
				$db->free_result();
			}
			// we're ok, use normal password auth
			return null;
		}
		else
		{
			// user did enter an OTP; make sure it's associated with the username
			$yubi_uid = $db->escape(substr($userdata['yubikey_otp'], 0, 12));
			$q = $db->sql_query('SELECT user_id FROM ' . table_prefix . 'yubikey WHERE yubi_uid = \'' . $yubi_uid . '\';');
			if ( !$q )
				$db->die_json();
			if ( $db->numrows() < 1 )
			{
				$db->free_result();
				return array(
						'mode' => 'error',
						'error' => 'yubiauth_err_key_not_authorized'
					);
			}
			list($yubi_pair_uid) = $db->fetchrow_num();
			if ( $yubi_pair_uid !== $user_id )
			{
				return array(
						'mode' => 'error',
						'error' => 'yubiauth_err_uid_mismatch'
					);
			}
			$db->free_result();
			$do_validate_otp = true;
		}
	}
	else if ( !empty($userdata['yubikey_otp']) )
	{
		// we have an OTP, but no username to work with
		$yubi_uid = substr($userdata['yubikey_otp'], 0, 12);
		if ( !preg_match('/^[cbdefghijklnrtuv]{12}$/', $yubi_uid ) )
		{
			return array(
					'mode' => 'error',
					'error' => 'yubiauth_err_invalid_otp'
				);
		}
		$q = $db->sql_query('SELECT u.user_id, u.username, u.user_yubikey_flags FROM ' . table_prefix . "users AS u\n"
											. "  LEFT JOIN " . table_prefix . "yubikey AS y\n"
											. "    ON ( y.user_id = u.user_id )\n"
											. "  WHERE y.yubi_uid = '$yubi_uid'\n"
											. "  GROUP BY u.user_yubikey_flags;");
		if ( !$q )
			$db->_die();
		
		if ( $db->numrows() < 1 )
		{
			if ( !$do_validate_pass )
				$session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"
 									. '  (\'security\', \'' . $auth_log_prefix . 'auth_bad\', '.time().', \'DEPRECATED\', \'(Yubikey)\', '
											. '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');
			
			return array(
					'mode' => 'error',
					'error' => 'yubiauth_err_key_not_authorized'
				);
		}
		
		list($user_id, $username, $flags) = $db->fetchrow_num();
		
		if ( $level > USER_LEVEL_MEMBER )
		{
			$session->start();
			if ( $session->user_logged_in && ($session->user_id !== $user_id) )
			{
				return array(
						'mode' => 'error',
						'error' => 'yubiauth_err_uid_mismatch'
					);
			}
		}
		
		$do_validate_otp = true;
		$do_validate_user = $flags & $user_flag;
		$do_validate_pass = $flags & $pass_flag;
		// to complete security logs later
		$userdata['username'] = $username;
	}
	else
	{
		// Nothing - no username or OTP. This request can't be used; throw it out.
		return array(
				'mode' => 'error',
				'error' => 'yubiauth_err_nothing_provided'
			);
	}
	
	if ( $do_validate_otp )
	{
		// We need to validate the OTP.
		$otp_check = yubikey_validate_otp($userdata['yubikey_otp']);
		if ( !$otp_check['success'] )
		{
			if ( !$do_validate_pass )
				$session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"
 									. '  (\'security\', \'' . $auth_log_prefix . 'auth_bad\', '.time().', \'DEPRECATED\', \'(Yubikey)\', '
											. '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');
			
			if ( $otp_check['error'] === 'http_failed' )
			{
				return array(
						'mode' => 'error',
						'error' => 'yubiauth_err_' . $otp_check['error'],
						'http_error' => $otp_check['http_error']
					);
			}
			return array(
					'mode' => 'error',
					'error' => 'yubiauth_err_' . $otp_check['error']
				);
		}
	}
	if ( $do_validate_user )
	{
		if ( empty($username) )
		{
			return array(
					'mode' => 'error',
					'error' => 'yubiauth_err_must_have_username'
				);
		}
		if ( strtolower($username) !== strtolower($userdata['username']) )
		{
			// Username incorrect
			if ( !$do_validate_pass )
				$session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"
 									. '  (\'security\', \'' . $auth_log_prefix . 'auth_bad\', '.time().', \'DEPRECATED\', \'(Yubikey)\', '
											. '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');
			return array(
					'mode' => 'error',
					'error' => 'invalid_credentials'
				);
		}
	}
	// Do we need to have the password validated?
	if ( $do_validate_pass )
	{
		if ( empty($userdata['password']) )
		{
			return array(
					'mode' => 'error',
					'error' => 'yubiauth_err_must_have_password'
				);
		}
		// Yes; return and let the login API continue
		return null;
	}
	else
	{
		// No password required; validated, issue session key
		$session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"
 									. '  (\'security\', \'' . $auth_log_prefix . 'auth_good\', '.time().', \'DEPRECATED\', \'' . $db->escape($userdata['username']) . '\', '
											. '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');
				
		$q = $db->sql_query('SELECT password FROM ' . table_prefix . "users WHERE user_id = $user_id;");
		if ( !$q )
			$db->_die();
		
		list($password) = $db->fetchrow_num();
		$db->free_result();
		
		$session->register_session($user_id, $userdata['username'], $password, intval($level), $remember);
		return true;
	}
}

function yubikey_add_special_pages()
{
	global $db, $session, $paths, $template, $plugins; // Common objects
	global $lang;
	
	if ( getConfig('yubikey_enable', '1') != '1' )
		return true;
	
	$paths->add_page(array(
			'name' => $lang->get('yubiauth_specialpage_yubikey'),
			'urlname' => 'Yubikey',
			'namespace' => 'Special',
			'visible' => 0, 'protected' => 0, 'comments_on' => 0, 'special' => 0
		));
}

function yubikey_sk_calc($user_id, &$key_pieces, &$sk_mode)
{
	global $db, $session, $paths, $template, $plugins; // Common objects
	// hash the user's yubikeys
	$q = $db->sql_query('SELECT yubi_uid FROM ' . table_prefix . "yubikey WHERE user_id = $user_id;");
	if ( !$q )
		$db->_die();
	
	while ( $row = $db->fetchrow() )
	{
		$key_pieces[] = $row['yubi_uid'];
	}
}

function page_Special_Yubikey()
{
	global $db, $session, $paths, $template, $plugins; // Common objects
	
	header('Content-type: text/javascript');
	/*
	if ( isset($_GET['validate_otp']) )
	{
		echo enano_json_encode(yubikey_validate_otp($_GET['validate_otp']));
		return true;
	}
	*/
	if ( isset($_GET['get_flags']) || isset($_POST['get_flags']) )
	{
		$yubi_uid = substr($_REQUEST['get_flags'], 0, 12);
		if ( !preg_match('/^[cbdefghijklnrtuv]{12}$/', $yubi_uid) )
		{
			return print enano_json_encode(array(
					'mode' => 'error',
					'error' => 'invalid_otp'
				));
		}
		$q = $db->sql_query('SELECT u.user_yubikey_flags FROM ' . table_prefix . "users AS u\n"
											. "  LEFT JOIN " . table_prefix . "yubikey AS y\n"
											. "    ON ( y.user_id = u.user_id )\n"
											. "  WHERE y.yubi_uid = '$yubi_uid'\n"
											. "  GROUP BY u.user_yubikey_flags;");
		if ( !$q )
			$db->_die();
		
		if ( $db->numrows() < 1 )
		{
			return print enano_json_encode(array(
					'mode' => 'error',
					'error' => 'key_not_authorized'
				));
		}
		
		list($flags) = $db->fetchrow_num();
		
		echo enano_json_encode(array(
				// We strip YK_SEC_ALLOW_NO_OTP here for security reasons.
				'flags' => intval($flags & ~YK_SEC_ALLOW_NO_OTP)
			));
		
		return true;
	}
}