class/deliver/Deliver_SMTP.class.php

   1 <?php
   2
   3 /**
   4  * Deliver_SMTP.class.php
   5  *
   6  * SMTP delivery backend for the Deliver class.
   7  *
   8  * @copyright 1999-2022 The SquirrelMail Project Team
   9  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  10  * @version $Id$
  11  * @package squirrelmail
  12  */
  13
  14 /** @ignore */
  15 if (!defined('SM_PATH')) define('SM_PATH','../../');
  16
  17 /** This of course depends upon Deliver */
  18 include_once(SM_PATH . 'class/deliver/Deliver.class.php');
  19
  20 /**
  21  * Deliver messages using SMTP
  22  * @package squirrelmail
  23  */
  24 class Deliver_SMTP extends Deliver {
  25     /**
  26      * Array keys are uppercased ehlo keywords
  27      * array key values are ehlo params. If ehlo-param contains space, it is splitted into array.
  28      * @var array ehlo
  29      * @since 1.5.1
  30      */
  31     var $ehlo = array();
  32     /**
  33      * @var string domain
  34      * @since 1.5.1
  35      */
  36     var $domain = '';
  37     /**
  38      * SMTP STARTTLS rfc: "Both the client and the server MUST know if there
  39      * is a TLS session active."
  40      * Variable should be set to true, when encryption is turned on.
  41      * @var boolean
  42      * @since 1.5.1
  43      */
  44     var $tls_enabled = false;
  45     /**
  46      * Private var
  47      * var stream $stream
  48      * @todo don't pass stream resource in class method arguments.
  49      */
  50     //var $stream = false;
  51     /** @var string delivery error message */
  52     var $dlv_msg = '';
  53     /** @var integer delivery error number from server */
  54     var $dlv_ret_nr = '';
  55     /** @var string delivery error message from server */
  56     var $dlv_server_msg = '';
  57
  58     function preWriteToStream(&$s) {
  59         if ($s) {
  60             if ($s[0] == '.')   $s = '.' . $s;
  61             $s = str_replace("\n.","\n..",$s);
  62         }
  63     }
  64
  65     function initStream($message, $domain, $length=0, $host='', $port='', $user='', $pass='', $authpop=false, $pop_host='', $stream_options=array()) {
  66         global $use_smtp_tls,$smtp_auth_mech;
  67
  68         if ($authpop) {
  69             $this->authPop($user, $pass, $pop_host, '');
  70         }
  71
  72         $rfc822_header = $message->rfc822_header;
  73
  74         $from = $rfc822_header->from[0];
  75         $to =   $rfc822_header->to;
  76         $cc =   $rfc822_header->cc;
  77         $bcc =  $rfc822_header->bcc;
  78         $content_type  = $rfc822_header->content_type;
  79
  80         // MAIL FROM: <from address> MUST be empty in cae of MDN (RFC2298)
  81         if ($content_type->type0 == 'multipart' &&
  82             $content_type->type1 == 'report' &&
  83             isset($content_type->properties['report-type']) &&
  84             $content_type->properties['report-type']=='disposition-notification') {
  85             // reinitialize the from object because otherwise the from header somehow
  86             // is affected. This $from var is used for smtp command MAIL FROM which
  87             // is not the same as what we put in the rfc822 header.
  88             $from = new AddressStructure();
  89             $from->host = '';
  90             $from->mailbox = '';
  91         }
  92
  93         // NB: Using "ssl://" ensures the highest possible TLS version
  94         // will be negotiated with the server (whereas "tls://" only
  95         // uses TLS version 1.0)
  96         //
  97         if ($use_smtp_tls == 1) {
  98             if ((check_php_version(4,3)) && (extension_loaded('openssl'))) {
  99                 if (function_exists('stream_socket_client')) {
 100                     $server_address = 'ssl://' . $host . ':' . $port;
 101                     $ssl_context = @stream_context_create($stream_options);
 102                     $connect_timeout = ini_get('default_socket_timeout');
 103                     // null timeout is broken
 104                     if ($connect_timeout == 0)
 105                         $connect_timeout = 30;
 106                     $stream = @stream_socket_client($server_address, $errorNumber, $errorString, $connect_timeout, STREAM_CLIENT_CONNECT, $ssl_context);
 107                 } else {
 108                     $stream = @fsockopen('ssl://' . $host, $port, $errorNumber, $errorString);
 109                 }
 110                 $this->tls_enabled = true;
 111             } else {
 112                 /**
 113                  * don't connect to server when user asks for smtps and
 114                  * PHP does not support it.
 115                  */
 116                 $errorNumber = '';
 117                 $errorString = _("Secure SMTP (TLS) is enabled in SquirrelMail configuration, but used PHP version does not support it.");
 118             }
 119         } else {
 120             $stream = @fsockopen($host, $port, $errorNumber, $errorString);
 121         }
 122
 123         if (!$stream) {
 124             // reset tls state var to default value, if connection fails
 125             $this->tls_enabled = false;
 126             // set error messages
 127             $this->dlv_msg = $errorString;
 128             $this->dlv_ret_nr = $errorNumber;
 129             $this->dlv_server_msg = _("Can't open SMTP stream.");
 130             return(0);
 131         }
 132         // get server greeting
 133         $tmp = fgets($stream, 1024);
 134         if ($this->errorCheck($tmp, $stream)) {
 135             return(0);
 136         }
 137
 138         /*
 139          * If $_SERVER['HTTP_HOST'] is set, use that in our HELO to the SMTP
 140          * server.  This should fix the DNS issues some people have had
 141          */
 142         if (sqgetGlobalVar('HTTP_HOST', $HTTP_HOST, SQ_SERVER)) { // HTTP_HOST is set
 143             // optionally trim off port number
 144             if($p = strrpos($HTTP_HOST, ':')) {
 145                 $HTTP_HOST = substr($HTTP_HOST, 0, $p);
 146             }
 147             $helohost = $HTTP_HOST;
 148         } else { // For some reason, HTTP_HOST is not set - revert to old behavior
 149             $helohost = $domain;
 150         }
 151
 152         // if the host is an IPv4 address, enclose it in brackets
 153         //
 154         if (preg_match('/^\d+\.\d+\.\d+\.\d+$/', $helohost))
 155             $helohost = '[' . $helohost . ']';
 156
 157         $hook_result = do_hook('smtp_helo_override', $helohost);
 158         if (!empty($hook_result)) $helohost = $hook_result;
 159
 160         /* Lets introduce ourselves */
 161         fputs($stream, "EHLO $helohost\r\n");
 162         // Read ehlo response
 163         $tmp = $this->parse_ehlo_response($stream);
 164         if ($this->errorCheck($tmp,$stream)) {
 165             // fall back to HELO if EHLO is not supported (error 5xx)
 166             if ($this->dlv_ret_nr[0] == '5') {
 167                 fputs($stream, "HELO $helohost\r\n");
 168                 $tmp = fgets($stream,1024);
 169                 if ($this->errorCheck($tmp,$stream)) {
 170                     return(0);
 171                 }
 172             } else {
 173                 return(0);
 174             }
 175         }
 176
 177         /**
 178          * Implementing SMTP STARTTLS (rfc2487) in php 5.1.0+
 179          * http://www.php.net/stream-socket-enable-crypto
 180          */
 181         if ($use_smtp_tls === 2) {
 182             if (function_exists('stream_socket_enable_crypto')) {
 183                 // don't try starting tls, when client thinks that it is already active
 184                 if ($this->tls_enabled) {
 185                     $this->dlv_msg = _("TLS session is already activated.");
 186                     return 0;
 187                 } elseif (!array_key_exists('STARTTLS',$this->ehlo)) {
 188                     // check for starttls in ehlo response
 189                     $this->dlv_msg = _("SMTP STARTTLS is enabled in SquirrelMail configuration, but used SMTP server does not support it");
 190                     return 0;
 191                 }
 192
 193                 // issue starttls command
 194                 fputs($stream, "STARTTLS\r\n");
 195                 // get response
 196                 $tmp = fgets($stream,1024);
 197                 if ($this->errorCheck($tmp,$stream)) {
 198                     return 0;
 199                 }
 200
 201                 // start crypto on connection. suppress function errors.
 202                 if (@stream_socket_enable_crypto($stream,true,STREAM_CRYPTO_METHOD_TLS_CLIENT)) {
 203                     // starttls was successful (rfc2487 5.2 Result of the STARTTLS Command)
 204                     // get new EHLO response
 205                     fputs($stream, "EHLO $helohost\r\n");
 206                     // Read ehlo response
 207                     $tmp = $this->parse_ehlo_response($stream);
 208                     if ($this->errorCheck($tmp,$stream)) {
 209                         // don't revert to helo here. server must support ESMTP
 210                         return 0;
 211                     }
 212                     // set information about started tls
 213                     $this->tls_enabled = true;
 214                 } else {
 215                     /**
 216                      * stream_socket_enable_crypto() call failed.
 217                      */
 218                     $this->dlv_msg = _("Unable to start TLS.");
 219                     return 0;
 220                     // Bug: can't get error message. See comments in sqimap_create_stream().
 221                 }
 222             } else {
 223                 // php install does not support stream_socket_enable_crypto() function
 224                 $this->dlv_msg = _("SMTP STARTTLS is enabled in SquirrelMail configuration, but used PHP version does not support functions that allow to enable encryption on open socket.");
 225                 return 0;
 226             }
 227         }
 228
 229         // FIXME: check ehlo response before using authentication
 230
 231         // Try authentication by a plugin
 232         //
 233         // NOTE: there is another hook in functions/auth.php called "smtp_auth"
 234         // that allows a plugin to specify a different set of login credentials
 235         // (so is slightly mis-named, but is too old to change), so be careful
 236         // that you do not confuse your hook names.
 237         //
 238         $smtp_auth_args = array(
 239             'auth_mech' => $smtp_auth_mech,
 240             'user' => $user,
 241             'pass' => $pass,
 242             'host' => $host,
 243             'port' => $port,
 244             'stream' => $stream,
 245         );
 246         if (boolean_hook_function('smtp_authenticate', $smtp_auth_args, 1)) {
 247             // authentication succeeded
 248         } else if (( $smtp_auth_mech == 'cram-md5') or ( $smtp_auth_mech == 'digest-md5' )) {
 249             // Doing some form of non-plain auth
 250             if ($smtp_auth_mech == 'cram-md5') {
 251                 fputs($stream, "AUTH CRAM-MD5\r\n");
 252             } elseif ($smtp_auth_mech == 'digest-md5') {
 253                 fputs($stream, "AUTH DIGEST-MD5\r\n");
 254             }
 255
 256             $tmp = fgets($stream,1024);
 257
 258             if ($this->errorCheck($tmp,$stream)) {
 259                 return(0);
 260             }
 261
 262             // At this point, $tmp should hold "334 <challenge string>"
 263             $chall = substr($tmp,4);
 264             // Depending on mechanism, generate response string
 265             if ($smtp_auth_mech == 'cram-md5') {
 266                 $response = cram_md5_response($user,$pass,$chall);
 267             } elseif ($smtp_auth_mech == 'digest-md5') {
 268                 $response = digest_md5_response($user,$pass,$chall,'smtp',$host);
 269             }
 270             fputs($stream, $response);
 271
 272             // Let's see what the server had to say about that
 273             $tmp = fgets($stream,1024);
 274             if ($this->errorCheck($tmp,$stream)) {
 275                 return(0);
 276             }
 277
 278             // CRAM-MD5 is done at this point.  If DIGEST-MD5, there's a bit more to go
 279             if ($smtp_auth_mech == 'digest-md5') {
 280                 // $tmp contains rspauth, but I don't store that yet. (No need yet)
 281                 fputs($stream,"\r\n");
 282                 $tmp = fgets($stream,1024);
 283
 284                 if ($this->errorCheck($tmp,$stream)) {
 285                 return(0);
 286                 }
 287             }
 288         // CRAM-MD5 and DIGEST-MD5 code ends here
 289         } elseif ($smtp_auth_mech == 'none') {
 290         // No auth at all, just send helo and then send the mail
 291         // We already said hi earlier, nothing more is needed.
 292         } elseif ($smtp_auth_mech == 'login') {
 293             // The LOGIN method
 294             fputs($stream, "AUTH LOGIN\r\n");
 295             $tmp = fgets($stream, 1024);
 296
 297             if ($this->errorCheck($tmp, $stream)) {
 298                 return(0);
 299             }
 300             fputs($stream, base64_encode ($user) . "\r\n");
 301             $tmp = fgets($stream, 1024);
 302             if ($this->errorCheck($tmp, $stream)) {
 303                 return(0);
 304             }
 305
 306             fputs($stream, base64_encode($pass) . "\r\n");
 307             $tmp = fgets($stream, 1024);
 308             if ($this->errorCheck($tmp, $stream)) {
 309                 return(0);
 310             }
 311         } elseif ($smtp_auth_mech == "plain") {
 312             /* SASL Plain */
 313             $auth = base64_encode("$user\0$user\0$pass");
 314
 315             $query = "AUTH PLAIN\r\n";
 316             fputs($stream, $query);
 317             $read=fgets($stream, 1024);
 318
 319             if (substr($read,0,3) == '334') { // OK so far..
 320                 fputs($stream, "$auth\r\n");
 321                 $read = fgets($stream, 1024);
 322             }
 323
 324             $results=explode(" ",$read,3);
 325             $response=$results[1];
 326             $message=$results[2];
 327         } else {
 328             /* Right here, they've reached an unsupported auth mechanism.
 329             This is the ugliest hack I've ever done, but it'll do till I can fix
 330             things up better tomorrow.  So tired... */
 331             if ($this->errorCheck("535 Unable to use this auth type",$stream)) {
 332                 return(0);
 333             }
 334         }
 335
 336         /* Ok, who is sending the message? */
 337         $fromaddress = (strlen($from->mailbox) && $from->host) ?
 338             $from->mailbox.'@'.$from->host : '';
 339         fputs($stream, 'MAIL FROM:<'.$fromaddress.">\r\n");
 340         $tmp = fgets($stream, 1024);
 341         if ($this->errorCheck($tmp, $stream)) {
 342             return(0);
 343         }
 344
 345         /* send who the recipients are */
 346         for ($i = 0, $cnt = count($to); $i < $cnt; $i++) {
 347             if (!$to[$i]->host) $to[$i]->host = $domain;
 348             if (strlen($to[$i]->mailbox)) {
 349                 // Ask for DSN if user has requested such and remote server supports it
 350                 if (isset($rfc822_header->dsn) && $rfc822_header->dsn
 351                  && array_key_exists('DSN',$this->ehlo)) {
 352                     // TODO: Make the DSN parameters configurable by admin? user?
 353                     fputs($stream, 'RCPT TO:<'.$to[$i]->mailbox.'@'.$to[$i]->host."> NOTIFY=SUCCESS,DELAY,FAILURE\r\n");
 354                     // Retry without DSN fields for cranky MTAs
 355                     if ($this->errorCheck($tmp, $stream)) {
 356                         fputs($stream, 'RCPT TO:<'.$to[$i]->mailbox.'@'.$to[$i]->host.">\r\n");
 357                     }
 358                 }
 359                 else
 360                     fputs($stream, 'RCPT TO:<'.$to[$i]->mailbox.'@'.$to[$i]->host.">\r\n");
 361                 $tmp = fgets($stream, 1024);
 362                 if ($this->errorCheck($tmp, $stream)) {
 363                     return(0);
 364                 }
 365             }
 366         }
 367
 368         for ($i = 0, $cnt = count($cc); $i < $cnt; $i++) {
 369             if (!$cc[$i]->host) $cc[$i]->host = $domain;
 370             if (strlen($cc[$i]->mailbox)) {
 371                 // Ask for DSN if user has requested such and remote server supports it
 372                 if (isset($rfc822_header->dsn) && $rfc822_header->dsn
 373                  && array_key_exists('DSN',$this->ehlo)) {
 374                     // TODO: Make the DSN parameters configurable by admin? user?
 375                     fputs($stream, 'RCPT TO:<'.$cc[$i]->mailbox.'@'.$cc[$i]->host."> NOTIFY=SUCCESS,DELAY,FAILURE\r\n");
 376                     // Retry without DSN fields for cranky MTAs
 377                     if ($this->errorCheck($tmp, $stream)) {
 378                         fputs($stream, 'RCPT TO:<'.$cc[$i]->mailbox.'@'.$cc[$i]->host.">\r\n");
 379                     }
 380                 }
 381                 else
 382                     fputs($stream, 'RCPT TO:<'.$cc[$i]->mailbox.'@'.$cc[$i]->host.">\r\n");
 383                 $tmp = fgets($stream, 1024);
 384                 if ($this->errorCheck($tmp, $stream)) {
 385                     return(0);
 386                 }
 387             }
 388         }
 389
 390         for ($i = 0, $cnt = count($bcc); $i < $cnt; $i++) {
 391             if (!$bcc[$i]->host) $bcc[$i]->host = $domain;
 392             if (strlen($bcc[$i]->mailbox)) {
 393                 // Ask for DSN if user has requested such and remote server supports it
 394                 if (isset($rfc822_header->dsn) && $rfc822_header->dsn
 395                  && array_key_exists('DSN',$this->ehlo)) {
 396                     // TODO: Make the DSN parameters configurable by admin? user?
 397                     fputs($stream, 'RCPT TO:<'.$bcc[$i]->mailbox.'@'.$bcc[$i]->host."> NOTIFY=SUCCESS,DELAY,FAILURE\r\n");
 398                     // Retry without DSN fields for cranky MTAs
 399                     if ($this->errorCheck($tmp, $stream)) {
 400                         fputs($stream, 'RCPT TO:<'.$bcc[$i]->mailbox.'@'.$bcc[$i]->host.">\r\n");
 401                     }
 402                 }
 403                 else
 404                     fputs($stream, 'RCPT TO:<'.$bcc[$i]->mailbox.'@'.$bcc[$i]->host.">\r\n");
 405                 $tmp = fgets($stream, 1024);
 406                 if ($this->errorCheck($tmp, $stream)) {
 407                     return(0);
 408                 }
 409             }
 410         }
 411         /* Lets start sending the actual message */
 412         fputs($stream, "DATA\r\n");
 413         $tmp = fgets($stream, 1024);
 414         if ($this->errorCheck($tmp, $stream)) {
 415                 return(0);
 416         }
 417         return $stream;
 418     }
 419
 420     function finalizeStream($stream) {
 421         fputs($stream, "\r\n.\r\n"); /* end the DATA part */
 422         $tmp = fgets($stream, 1024);
 423         $this->errorCheck($tmp, $stream);
 424         if ($this->dlv_ret_nr != 250) {
 425                 return(0);
 426         }
 427         fputs($stream, "QUIT\r\n"); /* log off */
 428         fclose($stream);
 429         return true;
 430     }
 431
 432     /* check if an SMTP reply is an error and set an error message) */
 433     function errorCheck($line, $smtpConnection) {
 434
 435         $err_num = substr($line, 0, 3);
 436         $this->dlv_ret_nr = $err_num;
 437         $server_msg = substr($line, 4);
 438
 439         while(substr($line, 0, 4) == ($err_num.'-')) {
 440             $line = fgets($smtpConnection, 1024);
 441             $server_msg .= substr($line, 4);
 442         }
 443
 444         if ( ((int) $err_num[0]) < 4) {
 445             return false;
 446         }
 447
 448         switch ($err_num) {
 449         case '421': $message = _("Service not available, closing channel");
 450             break;
 451         case '432': $message = _("A password transition is needed");
 452             break;
 453         case '450': $message = _("Requested mail action not taken: mailbox unavailable");
 454             break;
 455         case '451': $message = _("Requested action aborted: error in processing");
 456             break;
 457         case '452': $message = _("Requested action not taken: insufficient system storage");
 458             break;
 459         case '454': $message = _("Temporary authentication failure");
 460             break;
 461         case '500': $message = _("Syntax error; command not recognized");
 462             break;
 463         case '501': $message = _("Syntax error in parameters or arguments");
 464             break;
 465         case '502': $message = _("Command not implemented");
 466             break;
 467         case '503': $message = _("Bad sequence of commands");
 468             break;
 469         case '504': $message = _("Command parameter not implemented");
 470             break;
 471         case '530': $message = _("Authentication required");
 472             break;
 473         case '534': $message = _("Authentication mechanism is too weak");
 474             break;
 475         case '535': $message = _("Authentication failed");
 476             break;
 477         case '538': $message = _("Encryption required for requested authentication mechanism");
 478             break;
 479         case '550': $message = _("Requested action not taken: mailbox unavailable");
 480             break;
 481         case '551': $message = _("User not local; please try forwarding");
 482             break;
 483         case '552': $message = _("Requested mail action aborted: exceeding storage allocation");
 484             break;
 485         case '553': $message = _("Requested action not taken: mailbox name not allowed");
 486             break;
 487         case '554': $message = _("Transaction failed");
 488             break;
 489         default:    $message = _("Unknown response");
 490             break;
 491         }
 492
 493         $this->dlv_msg = $message;
 494         $this->dlv_server_msg = $server_msg;
 495
 496         return true;
 497     }
 498
 499     function authPop($user, $pass, $pop_server='', $pop_port='') {
 500         if (!$pop_port) {
 501             $pop_port = 110;
 502         }
 503         if (!$pop_server) {
 504             $pop_server = 'localhost';
 505         }
 506         $popConnection = @fsockopen($pop_server, $pop_port, $err_no, $err_str);
 507         if (!$popConnection) {
 508             error_log("Error connecting to POP Server ($pop_server:$pop_port)"
 509                 . " $err_no : $err_str");
 510             return false;
 511         } else {
 512             $tmp = fgets($popConnection, 1024); /* banner */
 513             if (substr($tmp, 0, 3) != '+OK') {
 514                 return false;
 515             }
 516             fputs($popConnection, "USER $user\r\n");
 517             $tmp = fgets($popConnection, 1024);
 518             if (substr($tmp, 0, 3) != '+OK') {
 519                 return false;
 520             }
 521             fputs($popConnection, 'PASS ' . $pass . "\r\n");
 522             $tmp = fgets($popConnection, 1024);
 523             if (substr($tmp, 0, 3) != '+OK') {
 524                 return false;
 525             }
 526             fputs($popConnection, "QUIT\r\n"); /* log off */
 527             fclose($popConnection);
 528         }
 529         return true;
 530     }
 531
 532     /**
 533      * Parses ESMTP EHLO response (rfc1869)
 534      *
 535      * Reads SMTP response to EHLO command and fills class variables
 536      * (ehlo array and domain string). Returns last line.
 537      * @param stream $stream smtp connection stream.
 538      * @return string last ehlo line
 539      * @since 1.5.1
 540      */
 541     function parse_ehlo_response($stream) {
 542         // don't cache ehlo information
 543         $this->ehlo=array();
 544         $ret = '';
 545         $firstline = true;
 546         /**
 547          * ehlo mailclient.example.org
 548          * 250-mail.example.org
 549          * 250-PIPELINING
 550          * 250-SIZE 52428800
 551          * 250-DATAZ
 552          * 250-STARTTLS
 553          * 250-AUTH LOGIN PLAIN
 554          * 250 8BITMIME
 555          */
 556         while ($line=fgets($stream, 1024)){
 557             // match[1] = first symbol after 250
 558             // match[2] = domain or ehlo-keyword
 559             // match[3] = greeting or ehlo-param
 560             // match space after keyword in ehlo-keyword CR LF
 561             if (preg_match("/^250(-|\s)(\S*)\s+(\S.*)\r\n/",$line,$match)||
 562                 preg_match("/^250(-|\s)(\S*)\s*\r\n/",$line,$match)) {
 563                 if ($firstline) {
 564                     // first ehlo line (250[-\ ]domain SP greeting)
 565                     $this->domain = $match[2];
 566                     $firstline=false;
 567                 } elseif (!isset($match[3])) {
 568                     // simple one word extension
 569                     $this->ehlo[strtoupper($match[2])]='';
 570                 } elseif (!preg_match("/\s/",trim($match[3]))) {
 571                     // extension with one option
 572                     // yes, I know about ctype extension. no, i don't want to depend on it
 573                     $this->ehlo[strtoupper($match[2])]=trim($match[3]);
 574                 } else {
 575                     // ehlo-param with spaces
 576                     $this->ehlo[strtoupper($match[2])]=explode(' ',trim($match[3]));
 577                 }
 578                 if ($match[1]==' ') {
 579                     // stop while cycle, if we reach last 250 line
 580                     $ret = $line;
 581                     break;
 582                 }
 583             } else {
 584                 // this is not 250 response
 585                 $ret = $line;
 586                 break;
 587             }
 588         }
 589         return $ret;
 590     }
 591 }