mail_plugin_dkim.inc.php

<?php

/**
 Copyright (c) 2007 - 2013, Till Brehm, projektfarm Gmbh
 Copyright (c) 2013, Florian Schaal, info@schaal-24.de
 All rights reserved.

 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
 this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice,
 this list of conditions and the following disclaimer in the documentation
 and/or other materials provided with the distribution.
 * Neither the name of ISPConfig nor the names of its contributors
 may be used to endorse or promote products derived from this software without
 specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 @author Florian Schaal, info@schaal-24.de
 @copyrighth Florian Schaal, info@schaal-24.de
 */


class mail_plugin_dkim {

	var $plugin_name = 'mail_plugin_dkim';
	var $class_name = 'mail_plugin_dkim';

	// private variables
	var $action = '';

	/**
	 * This function is called during ispconfig installation to determine
	 * if a symlink shall be created for this plugin.
	 */
	function onInstall() {
		global $conf;

		if($conf['services']['mail'] == true) {
			return true;
		} else {
			return false;
		}

	}

	/**
	 * This function is called when the plugin is loaded
	 */
	function onLoad() {
		global $app, $conf;
		/*
		Register for the events
		*/
		$app->plugins->registerEvent('mail_domain_delete', $this->plugin_name, 'domain_dkim_delete');
		$app->plugins->registerEvent('mail_domain_insert', $this->plugin_name, 'domain_dkim_insert');
		$app->plugins->registerEvent('mail_domain_update', $this->plugin_name, 'domain_dkim_update');
	}

	/**
	 * This function gets the amavisd-config file
	 * @return string path to the amavisd-config for dkim-keys
	 */
	function get_amavis_config() {
		$pos_config=array(
			'/etc/amavisd.conf',
			'/etc/amavisd.conf/50-user',
			'/etc/amavis/conf.d/50-user',
			'/etc/amavisd/amavisd.conf'
		);
		$amavis_configfile='';
		foreach($pos_config as $conf) {
			if (is_file($conf)) {
				$amavis_configfile=$conf;
				break;
			}
		}
		//* If we can use seperate config-files with amavis use 60-dkim
		if (substr_compare($amavis_configfile, '50-user', -7) === 0)
			$amavis_configfile = str_replace('50-user', '60-dkim', $amavis_configfile);

		return $amavis_configfile;
	}

	/**
	 * This function checks the relevant configs and disables dkim for the domain
	 * if the directory for dkim is not writeable or does not exist
	 * @param array $data mail-settings
	 * @return boolean - true when the amavis-config and the dkim-dir are writeable
	 */
	function check_system($data) {
		global $app, $mail_config;

		$app->uses('getconf');
		$check=true;

		/* check for amavis-config */
		$amavis_configfile = $this->get_amavis_config();

		//* When we can use 60-dkim for the dkim-keys create the file if it does not exists.
		if (substr_compare($amavis_configfile, '60-dkim', -7) === 0 && !file_exists($amavis_configfile))
			$app->system->touch($amavis_configfile);

		if ( $amavis_configfile == '' || !is_writeable($amavis_configfile) ) {
			$app->log('Amavis-config not found or not writeable.', LOGLEVEL_ERROR);
			$check=false;
		}

		/* dir for dkim-keys writeable? */
		$mail_config = $app->getconf->get_server_config($conf['server_id'], 'mail');
		if (	isset($mail_config['dkim_path']) && 
				!empty($mail_config['dkim_path']) && 
				isset($data['new']['dkim_private']) && 
				!empty($data['new']['dkim_private']) &&
				$mail_config['dkim_path'] != '/' 
		) {
            if (!is_dir($mail_config['dkim_path'])) {
                $app->log('DKIM Path '.$mail_config['dkim_path'].' not found - (re)created.', LOGLEVEL_DEBUG);
				if($app->system->is_user('amavis')) { 
					$amavis_user='amavis'; 
				} elseif ($app->system->is_user('vscan')) { 
					$amavis_user='vscan'; 
				}
				else { 
					$amavis_user=''; 
				}
				if(!empty($amavis_user)) {
					mkdir($mail_config['dkim_path'], 0750, true);
					$app->system->chown($mail_config['dkim_path'], $amavis_user);
				} else {
					mkdir($mail_config['dkim_path'], 0755, true);
					$app->log('No user amavis or vscan found - using root for '.$mail_config['dkim_path'], LOGLEVEL_WARNING);
				}
            } else {
				if (!$app->system->checkpath($mail_config['dkim_path'])) {
					$app->log('Unable to write DKIM settings - invalid DKIM-Path (symlink?)', LOGLEVEL_ERROR);
					$check=false;
				}
			}

			if (!is_writeable($mail_config['dkim_path'])) {
				$app->log('DKIM Path '.$mail_config['dkim_path'].' not writeable.', LOGLEVEL_ERROR);
				$check=false;
			}

			if ( !$app->system->checkpath($mail_config['dkim_path']) ) {
				$app->log('DKIM Path '.$mail_config['dkim_path'].' failed in checkpath.', LOGLEVEL_ERROR);
				$check = false;
			}

		} else {
			$app->log('Unable to write DKIM settings - no or invalid DKIM-Path defined', LOGLEVEL_ERROR);
			$check=false;
		}
		return $check;
	}

	/**
	 * This function restarts amavis
	 */
    function restart_amavis() {
        global $app, $conf;
        $pos_init=array(
            $conf['init_scripts'].'/amavis',
            $conf['init_scripts'].'/amavisd'
        );
        $initfile='';
        foreach($pos_init as $init) {
            if (is_executable($init)) {
                $initfile=$init;
                break;
                }
        }
		if ( $initfile == '' ) $initfile = 'service amavis';
        $app->log('Restarting amavis: '.$initfile.'.', LOGLEVEL_DEBUG);
        exec(escapeshellarg($initfile).' restart', $output);
        foreach($output as $logline) $app->log($logline, LOGLEVEL_DEBUG);
    }

	/**
	 * This function writes the keyfiles (public and private)
	 * @param string $key_file full path to the key-file
	 * @param string $key_value private-key
	 * @param string $key_domain mail-domain
	 * @return bool - true when the private key was written to disk
	 */
	function write_dkim_key($key_file, $key_value, $key_domain) {
		global $app, $mailconfig;
		$success=false;
		if ( $app->system->file_put_contents($key_file.'.private', $key_value) ) {
			$app->log('Saved DKIM Private-key to '.$key_file.'.private', LOGLEVEL_DEBUG);
			$success=true;
			/* now we get the DKIM Public-key */
			exec('cat '.escapeshellarg($key_file.'.private').'|openssl rsa -pubout 2> /dev/null', $pubkey, $result);
			$public_key='';
			foreach($pubkey as $values) $public_key=$public_key.$values."\n";
			/* save the DKIM Public-key in dkim-dir */
			if ( $app->system->file_put_contents($key_file.'.public', $public_key) )
				$app->log('Saved DKIM Public to '.$key_domain.'.', LOGLEVEL_DEBUG);
			else $app->log('Unable to save DKIM Public to '.$key_domain.'.', LOGLEVEL_DEBUG);
		} else {
			$app->log('Unable to save DKIM Privte-key to '.$key_file.'.private', LOGLEVEL_ERROR);
		}
		return $success;
	}

	/**
	 * This function removes the keyfiles
	 * @param string $key_file full path to the key-file
	 * @param string $key_domain mail-domain
	 */
	function remove_dkim_key($key_file, $key_domain) {
		global $app;
		if (file_exists($key_file.'.private')) {
			$app->system->unlink($key_file.'.private');
			$app->log('Deleted the DKIM Private-key for '.$key_domain.'.', LOGLEVEL_DEBUG);
		} else $app->log('Unable to delete the DKIM Private-key for '.$key_domain.' (not found).', LOGLEVEL_DEBUG);
		if (file_exists($key_file.'.public')) {
			$app->system->unlink($key_file.'.public');
			$app->log('Deleted the DKIM Public-key for '.$key_domain.'.', LOGLEVEL_DEBUG);
		} else $app->log('Unable to delete the DKIM Public-key for '.$key_domain.' (not found).', LOGLEVEL_DEBUG);
	}

	/**
	 * This function adds the entry to the amavisd-config
	 * @param string $key_domain mail-domain
	 */
	function add_to_amavis($key_domain, $selector, $old_selector) {
		global $app, $mail_config;

		if (empty($selector)) $selector = 'default';
		$restart = false;
		$amavis_configfile = $this->get_amavis_config();

		$search_regex = "/(\n|\r)?dkim_key\(\'".$key_domain."\',\ \'(".$selector."|".$old_selector."){1}?\'.*/";

		//* If we are using seperate config-files with amavis remove existing keys from 50-user to avoid duplicate keys
		if (substr_compare($amavis_configfile, '60-dkim', -7) === 0) {
			$temp_configfile = str_replace('60-dkim', '50-user', $amavis_configfile);
			$temp_config = $app->system->file_get_contents($temp_configfile, true);
			if (preg_match($search_regex, $temp_config)) {
				$temp_config = preg_replace($search_regex, '', $temp_config)."\n";
				$app->system->file_put_contents($temp_configfile, $temp_config, true);
			}
			unset($temp_configfile);
			unset($temp_config);
		}

		$key_value="dkim_key('".$key_domain."', '".$selector."', '".$mail_config['dkim_path']."/".$key_domain.".private');\n";
		$amavis_config = $app->system->file_get_contents($amavis_configfile, true);
		$amavis_config = preg_replace($search_regex, '', $amavis_config).$key_value;

		if ( $app->system->file_put_contents($amavis_configfile, $amavis_config, true) ) {
			$app->log('Adding DKIM Private-key to amavis-config.', LOGLEVEL_DEBUG);
			$restart = true;
		} else {
			$app->log('Unable to add DKIM Private-key for '.$key_domain.' to amavis-config.', LOGLEVEL_ERROR);
		}

		return $restart;
	}

	/**
	 * This function removes the entry from the amavisd-config
	 * @param string $key_domain mail-domain
	 */
	function remove_from_amavis($key_domain) {
		global $app;

		$restart = false;
		$amavis_configfile = $this->get_amavis_config();
		$amavis_config = $app->system->file_get_contents($amavis_configfile, true);

		$search_regex = "/(\n|\r)?dkim_key.*".$key_domain.".*(\n|\r)?/";

		if (preg_match($search_regex, $amavis_config)) {
			$amavis_config = preg_replace($search_regex, '', $amavis_config);
			$app->system->file_put_contents($amavis_configfile, $amavis_config, true);
			$app->log('Deleted the DKIM settings from amavis-config for '.$key_domain.'.', LOGLEVEL_DEBUG);
			$restart = true;
		}

		//* If we are using seperate config-files with amavis remove existing keys from 50-user, too
		if (substr_compare($amavis_configfile, '60-dkim', -7) === 0) {
			$temp_configfile = str_replace('60-dkim', '50-user', $amavis_configfile);
			$temp_config = $app->system->file_get_contents($temp_configfile, true);
			if (preg_match($search_regex, $temp_config)) {
				$temp_config = preg_replace($search_regex, '', $temp_config);
				$app->system->file_put_contents($temp_configfile, $temp_config, true);
				$restart = true;
			}
			unset($temp_configfile);
			unset($temp_config);
		}

		return $restart;
	}

	/**
	 * This function controlls new key-files and amavisd-entries
	 * @param array $data mail-settings
	 */
	function add_dkim($data) {
		global $app;
		if ($data['new']['active'] == 'y') {
			$mail_config = $app->getconf->get_server_config($conf['server_id'], 'mail');
			if ( substr($mail_config['dkim_path'], strlen($mail_config['dkim_path'])-1) == '/' )
				$mail_config['dkim_path'] = substr($mail_config['dkim_path'], 0, strlen($mail_config['dkim_path'])-1);
			if ($this->write_dkim_key($mail_config['dkim_path']."/".$data['new']['domain'], $data['new']['dkim_private'], $data['new']['domain'])) {
				if ($this->add_to_amavis($data['new']['domain'], $data['new']['dkim_selector'], $data['old']['dkim_selector'] )) {
					$this->restart_amavis();
				} else {
					$this->remove_dkim_key($mail_config['dkim_path']."/".$data['new']['domain'], $data['new']['domain']);
				}
			} else {
				$app->log('Error saving the DKIM Private-key for '.$data['new']['domain'].' - DKIM is not enabled for the domain.', LOGLEVEL_ERROR);
			}
		}
	}

	/**
	 * This function controlls the removement of keyfiles (public and private)
	 * and the entry in the amavisd-config
	 * @param array $data mail-settings
	 */
	function remove_dkim($_data) {
		global $app;
		$mail_config = $app->getconf->get_server_config($conf['server_id'], 'mail');
		if ( substr($mail_config['dkim_path'], strlen($mail_config['dkim_path'])-1) == '/' )
			$mail_config['dkim_path'] = substr($mail_config['dkim_path'], 0, strlen($mail_config['dkim_path'])-1);
		$this->remove_dkim_key($mail_config['dkim_path']."/".$_data['domain'], $_data['domain']);
		if ($this->remove_from_amavis($_data['domain']))
			$this->restart_amavis();
	}

	/**
	 * Function called by onLoad
	 * deletes dkim-keys
	 */
	function domain_dkim_delete($event_name, $data) {
		if (isset($data['old']['dkim']) && $data['old']['dkim'] == 'y' && $data['old']['active'] == 'y')
			$this->remove_dkim($data['old']);
	}

	/**
	 * Function called by onLoad
	 * insert dkim-keys
	 */
	function domain_dkim_insert($event_name, $data) {
		if (isset($data['new']['dkim']) && $data['new']['dkim']=='y' && $this->check_system($data))
			$this->add_dkim($data);
	}

	/**
	 * Function called by onLoad
	 * chang dkim-settings
	 */
	function domain_dkim_update($event_name, $data) {
		global $app;
		if ($this->check_system($data)) {
			/* maildomain disabled */
			if ($data['new']['active'] == 'n' && $data['old']['active'] == 'y' && $data['new']['dkim']=='y') {
				$app->log('Maildomain '.$data['new']['domain'].' disabled - remove DKIM-settings', LOGLEVEL_DEBUG);
				$this->remove_dkim($data['new']);
			}
			/* maildomain re-enabled */
			if ($data['new']['active'] == 'y' && $data['old']['active'] == 'n' && $data['new']['dkim']=='y') 
				$this->add_dkim($data);

			/* maildomain active - only dkim changes */
			if ($data['new']['active'] == 'y' && $data['old']['active'] == 'y') {
				/* dkim disabled */
				if ($data['new']['dkim'] != $data['old']['dkim'] && $data['new']['dkim'] == 'n') {
					$this->remove_dkim($data['new']);
				}
				/* dkim enabled */
				elseif ($data['new']['dkim'] != $data['old']['dkim'] && $data['new']['dkim'] == 'y') {
					$this->add_dkim($data);
				}
				/* new private-key */
				if ($data['new']['dkim_private'] != $data['old']['dkim_private'] && $data['new']['dkim'] == 'y') {
					$this->add_dkim($data);
				}
				/* new selector */
				if ($data['new']['dkim_selector'] != $data['old']['dkim_selector'] && $data['new']['dkim'] == 'y') {
					$this->add_dkim($data);
				}
				/* new domain-name */
				if ($data['new']['domain'] != $data['old']['domain']) {
					$this->remove_dkim($data['old']);
					$this->add_dkim($data);
				}
			}

			/* resync */
			if ($data['new']['active'] == 'y' && $data['new'] == $data['old']) {
				$this->add_dkim($data);
			}
		}
	}

}

?>