functions/mime.php

   1 <?php
   2
   3 /**
   4  * mime.php
   5  *
   6  * This contains the functions necessary to detect and decode MIME
   7  * messages.
   8  *
   9  * @copyright 1999-2021 The SquirrelMail Project Team
  10  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  11  * @version $Id$
  12  * @package squirrelmail
  13  */
  14
  15 /**
  16  * dependency information
  17    functions       dependency
  18    mime_structure
  19         class/mime/Message.class.php
  20             Message::parseStructure
  21         functions/page_header.php
  22             displayPageHeader
  23         functions/display_messages.php
  24             plain_error_message
  25    mime_fetch_body
  26         functions/imap_general.php
  27             sqimap_run_command
  28    mime_print_body_lines
  29
  30
  31
  32 functions/imap.php
  33 functions/attachment_common.php
  34 functions/display_messages.php
  35
  36 magicHtml => url_parser
  37 translateText => url_parser
  38
  39 */
  40
  41
  42 /* -------------------------------------------------------------------------- */
  43 /* MIME DECODING                                                              */
  44 /* -------------------------------------------------------------------------- */
  45
  46 /**
  47  * Get the MIME structure
  48  *
  49  * This function gets the structure of a message and stores it in the "message" class.
  50  * It will return this object for use with all relevant header information and
  51  * fully parsed into the standard "message" object format.
  52  */
  53 function mime_structure ($bodystructure, $flags=array()) {
  54
  55     /* Isolate the body structure and remove beginning and end parenthesis. */
  56     $read = trim(substr ($bodystructure, strpos(strtolower($bodystructure), 'bodystructure') + 13));
  57     $read = trim(substr ($read, 0, -1));
  58     $i = 0;
  59     $msg = Message::parseStructure($read,$i);
  60
  61     if (!is_object($msg)) {
  62         global $color, $mailbox;
  63         displayPageHeader( $color, $mailbox );
  64         $errormessage  = _("SquirrelMail could not decode the bodystructure of the message");
  65         $errormessage .= '<br />'._("The bodystructure provided by your IMAP server:").'<br /><br />';
  66         $errormessage .= '<pre>' . sm_encode_html_special_chars($read) . '</pre>';
  67         plain_error_message( $errormessage );
  68         echo '</body></html>';
  69         exit;
  70     }
  71     if (count($flags)) {
  72         foreach ($flags as $flag) {
  73 //FIXME: please document why it is we have to check the first char of the flag but we then go ahead and do a full string comparison anyway.  Is this a speed enhancement?  If not, let's keep it simple and just compare the full string and forget the switch block.
  74             $char = strtoupper($flag[1]);
  75             switch ($char) {
  76                 case 'S':
  77                     if (strtolower($flag) == '\\seen') {
  78                         $msg->is_seen = true;
  79                     }
  80                     break;
  81                 case 'A':
  82                     if (strtolower($flag) == '\\answered') {
  83                         $msg->is_answered = true;
  84                     }
  85                     break;
  86                 case 'D':
  87                     if (strtolower($flag) == '\\deleted') {
  88                         $msg->is_deleted = true;
  89                     }
  90                     break;
  91                 case 'F':
  92                     if (strtolower($flag) == '\\flagged') {
  93                         $msg->is_flagged = true;
  94                     }
  95                     else if (strtolower($flag) == '$forwarded') {
  96                         $msg->is_forwarded = true;
  97                     }
  98                     break;
  99                 case 'M':
 100                     if (strtolower($flag) == '$mdnsent') {
 101                         $msg->is_mdnsent = true;
 102                     }
 103                     break;
 104                 default:
 105                     break;
 106             }
 107         }
 108     }
 109     //    listEntities($msg);
 110     return $msg;
 111 }
 112
 113
 114
 115 /* This starts the parsing of a particular structure.  It is called recursively,
 116  * so it can be passed different structures.  It returns an object of type
 117  * $message.
 118  * First, it checks to see if it is a multipart message.  If it is, then it
 119  * handles that as it sees is necessary.  If it is just a regular entity,
 120  * then it parses it and adds the necessary header information (by calling out
 121  * to mime_get_elements()
 122  */
 123
 124 function mime_fetch_body($imap_stream, $id, $ent_id=1, $fetch_size=0) {
 125     /* Do a bit of error correction.  If we couldn't find the entity id, just guess
 126      * that it is the first one.  That is usually the case anyway.
 127      */
 128
 129     if (!$ent_id) {
 130         $cmd = "FETCH $id BODY[]";
 131     } else {
 132         $cmd = "FETCH $id BODY[$ent_id]";
 133     }
 134
 135     if ($fetch_size!=0) $cmd .= "<0.$fetch_size>";
 136
 137     $data = sqimap_run_command ($imap_stream, $cmd, true, $response, $message, TRUE);
 138     do {
 139         $topline = trim(array_shift($data));
 140     } while($topline && ($topline[0] == '*') && !preg_match('/\* [0-9]+ FETCH .*BODY.*/i', $topline)) ;
 141     // Matching with "BODY" above is difficult: in most cases "FETCH \(BODY" would work
 142     // but some servers may put other things in the same result, perhaps something such
 143     // as "* 23 FETCH (FLAGS (\Seen) BODY[1] {174}".  There is some small chance that
 144     // if the character sequence "BODY" appears in a response where it isn't actually
 145     // a FETCH response data item name, the current regex will break things.  The better
 146     // way to do this would be to parse the response correctly and not use a regex.
 147
 148     $wholemessage = implode('', $data);
 149     if (preg_match('/\{([^\}]*)\}/', $topline, $regs)) {
 150         $ret = substr($wholemessage, 0, $regs[1]);
 151         /* There is some information in the content info header that could be important
 152          * in order to parse html messages. Let's get them here.
 153          */
 154 //        if ($ret[0] == '<') {
 155 //            $data = sqimap_run_command ($imap_stream, "FETCH $id BODY[$ent_id.MIME]", true, $response, $message, TRUE);
 156 //        }
 157     } else if (preg_match('/"([^"]*)"/', $topline, $regs)) {
 158         $ret = $regs[1];
 159     } else if ((stristr($topline, 'nil') !== false) && (empty($wholemessage))) {
 160         $ret = $wholemessage;
 161     } else {
 162         global $where, $what, $mailbox, $passed_id, $startMessage;
 163         $par = 'mailbox=' . urlencode($mailbox) . '&amp;passed_id=' . $passed_id;
 164         if (isset($where) && isset($what)) {
 165             $par .= '&amp;where=' . urlencode($where) . '&amp;what=' . urlencode($what);
 166         } else {
 167             $par .= '&amp;startMessage=' . $startMessage . '&amp;show_more=0';
 168         }
 169         $par .= '&amp;response=' . urlencode($response) .
 170             '&amp;message='  . urlencode($message)  .
 171             '&amp;topline='  . urlencode($topline);
 172
 173         echo '<tt><br />' .
 174             '<table width="80%"><tr>' .
 175             '<tr><td colspan="2">' .
 176             _("Body retrieval error. The reason for this is most probably that the message is malformed.") .
 177             '</td></tr>' .
 178             '<tr><td><b>' . _("Command:") . "</td><td>$cmd</td></tr>" .
 179             '<tr><td><b>' . _("Response:") . "</td><td>$response</td></tr>" .
 180             '<tr><td><b>' . _("Message:") . "</td><td>$message</td></tr>" .
 181             '<tr><td><b>' . _("FETCH line:") . "</td><td>$topline</td></tr>" .
 182             "</table><br /></tt></font><hr />";
 183
 184         $data = sqimap_run_command ($imap_stream, "FETCH $passed_id BODY[]", true, $response, $message, TRUE);
 185         array_shift($data);
 186         $wholemessage = implode('', $data);
 187
 188         $ret = $wholemessage;
 189     }
 190     return $ret;
 191 }
 192
 193 // TODO: Needs documentation.  $ent_id default is usually 1
 194 function mime_print_body_lines ($imap_stream, $id, $ent_id, $encoding, $rStream='php://stdout', $force_crlf='') {
 195
 196     /* Don't kill the connection if the browser is over a dialup
 197      * and it would take over 30 seconds to download it.
 198      * Don't call set_time_limit in safe mode.
 199      */
 200
 201     if (!ini_get('safe_mode')) {
 202         set_time_limit(0);
 203     }
 204     /* in case of base64 encoded attachments, do not buffer them.
 205        Instead, echo the decoded attachment directly to screen */
 206     if (strtolower($encoding) == 'base64') {
 207         if (!$ent_id) {
 208             $query = "FETCH $id BODY[]";
 209         } else {
 210             $query = "FETCH $id BODY[$ent_id]";
 211         }
 212         sqimap_run_command($imap_stream,$query,true,$response,$message,TRUE,'sqimap_base64_decode',$rStream,true);
 213     } else {
 214         $body = mime_fetch_body ($imap_stream, $id, $ent_id);
 215         if (is_resource($rStream)) {
 216             fputs($rStream,decodeBody($body, $encoding, $force_crlf));
 217         } else {
 218             echo decodeBody($body, $encoding, $force_crlf);
 219         }
 220     }
 221
 222     /*
 223        TODO, use the same method for quoted printable.
 224        However, I assume that quoted printable attachments aren't that large
 225        so the performancegain / memory usage drop will be minimal.
 226        If we decide to add that then we need to adapt sqimap_fread because
 227        we need to split te result on \n and fread doesn't stop at \n. That
 228        means we also should provide $results from sqimap_fread (by ref) to
 229        te function and set $no_return to false. The $filter function for
 230        quoted printable should handle unsetting of $results.
 231      */
 232     /*
 233        TODO 2: find out how we write to the output stream php://stdout. fwrite
 234        doesn't work because 'php://stdout isn't a stream.
 235      */
 236
 237     return;
 238 }
 239
 240 /* -[ END MIME DECODING ]----------------------------------------------------------- */
 241
 242 /* This is here for debugging purposes.  It will print out a list
 243  * of all the entity IDs that are in the $message object.
 244  */
 245 function listEntities ($message) {
 246     if ($message) {
 247         echo "<tt>" . $message->entity_id . ' : ' . $message->type0 . '/' . $message->type1 . ' parent = '. $message->parent->entity_id. '<br />';
 248         for ($i = 0; isset($message->entities[$i]); $i++) {
 249             echo "$i : ";
 250             $msg = listEntities($message->entities[$i]);
 251
 252             if ($msg) {
 253                 echo "return: ";
 254                 return $msg;
 255             }
 256         }
 257     }
 258 }
 259
 260 function getPriorityStr($priority) {
 261     $priority_level = substr($priority,0,1);
 262
 263     switch($priority_level) {
 264         /* Check for a higher then normal priority. */
 265         case '1':
 266         case '2':
 267             $priority_string = _("High");
 268             break;
 269
 270         /* Check for a lower then normal priority. */
 271         case '4':
 272         case '5':
 273             $priority_string = _("Low");
 274             break;
 275
 276         /* Check for a normal priority. */
 277         case '3':
 278         default:
 279             $priority_level = '3';
 280             $priority_string = _("Normal");
 281             break;
 282
 283     }
 284     return $priority_string;
 285 }
 286
 287 /* returns a $message object for a particular entity id */
 288 function getEntity ($message, $ent_id) {
 289     return $message->getEntity($ent_id);
 290 }
 291
 292 /* translateText
 293  * Extracted from strings.php 23/03/2002
 294  */
 295
 296 function translateText(&$body, $wrap_at, $charset) {
 297     global $where, $what;   /* from searching */
 298     global $color;          /* color theme */
 299
 300     // require_once(SM_PATH . 'functions/url_parser.php');
 301
 302     $body_ary = explode("\n", $body);
 303     for ($i=0; $i < count($body_ary); $i++) {
 304         $line = rtrim($body_ary[$i],"\r");
 305
 306         if (strlen($line) - 2 >= $wrap_at) {
 307             sqWordWrap($line, $wrap_at, $charset);
 308         }
 309         $line = charset_decode($charset, $line);
 310         $line = str_replace("\t", '        ', $line);
 311
 312         parseUrl ($line);
 313
 314         $quotes = 0;
 315         $pos = 0;
 316         $j = strlen($line);
 317
 318         while ($pos < $j) {
 319             if ($line[$pos] == ' ') {
 320                 $pos++;
 321             } else if (strpos($line, '&gt;', $pos) === $pos) {
 322                 $pos += 4;
 323                 $quotes++;
 324             } else {
 325                 break;
 326             }
 327         }
 328
 329         if ($quotes % 2) {
 330             $line = '<span class="quote1">' . $line . '</span>';
 331         } elseif ($quotes) {
 332             $line = '<span class="quote2">' . $line . '</span>';
 333         }
 334
 335         $body_ary[$i] = $line;
 336     }
 337     $body = '<pre>' . implode("\n", $body_ary) . '</pre>';
 338 }
 339
 340 /**
 341  * This returns a parsed string called $body. That string can then
 342  * be displayed as the actual message in the HTML. It contains
 343  * everything needed, including HTML Tags, Attachments at the
 344  * bottom, etc.
 345  *
 346  * Since 1.2.0 function uses message_body hook.
 347  * Till 1.3.0 function included output of formatAttachments().
 348  *
 349  * @param resource $imap_stream imap connection resource
 350  * @param object $message squirrelmail message object
 351  * @param array $color squirrelmail color theme array
 352  * @param integer $wrap_at number of characters per line
 353  * @param string $ent_num (since 1.3.0) message part id
 354  * @param integer $id (since 1.3.0) message id
 355  * @param string $mailbox (since 1.3.0) imap folder name
 356  * @return string html formated message text
 357  */
 358 function formatBody($imap_stream, $message, $color, $wrap_at, $ent_num, $id, $mailbox='INBOX') {
 359     /* This if statement checks for the entity to show as the
 360      * primary message. To add more of them, just put them in the
 361      * order that is their priority.
 362      */
 363     global $startMessage, $languages, $squirrelmail_language,
 364            $show_html_default, $sort, $has_unsafe_images, $passed_ent_id,
 365            $use_iframe, $iframe_height, $download_and_unsafe_link,
 366            $download_href, $unsafe_image_toggle_href, $unsafe_image_toggle_text,
 367            $oTemplate, $nbsp;
 368
 369     // workaround for not updated config.php
 370     if (! isset($use_iframe)) $use_iframe = false;
 371
 372     // If there's no "view_unsafe_images" variable in the URL, turn unsafe
 373     // images off by default.
 374     sqgetGlobalVar('view_unsafe_images', $view_unsafe_images, SQ_GET, FALSE);
 375
 376     $body = '';
 377     $urlmailbox = urlencode($mailbox);
 378     $body_message = getEntity($message, $ent_num);
 379     if (($body_message->header->type0 == 'text') ||
 380             ($body_message->header->type0 == 'rfc822')) {
 381         $body = mime_fetch_body ($imap_stream, $id, $ent_num);
 382         $body = decodeBody($body, $body_message->header->encoding);
 383
 384         if (isset($languages[$squirrelmail_language]['XTRA_CODE']) &&
 385                 function_exists($languages[$squirrelmail_language]['XTRA_CODE'] . '_decode')) {
 386             if (mb_detect_encoding($body) != 'ASCII') {
 387                 $body = call_user_func($languages[$squirrelmail_language]['XTRA_CODE'] . '_decode',$body);
 388             }
 389         }
 390
 391         /* As of 1.5.2, $body is passed (and modified) by reference */
 392         do_hook('message_body', $body);
 393
 394         /* If there are other types that shouldn't be formatted, add
 395          * them here.
 396          */
 397
 398         if ($body_message->header->type1 == 'html') {
 399             if ($show_html_default <> 1) {
 400                 $entity_conv = array('&nbsp;' => ' ',
 401                                      '<p>'    => "\n",
 402                                      '<P>'    => "\n",
 403                                      '<br>'   => "\n",
 404                                      '<BR>'   => "\n",
 405                                      '<br />' => "\n",
 406                                      '<BR />' => "\n",
 407                                      '&gt;'   => '>',
 408                                      '&lt;'   => '<');
 409                 $body = strtr($body, $entity_conv);
 410                 $body = strip_tags($body);
 411                 $body = trim($body);
 412                 translateText($body, $wrap_at,
 413                         $body_message->header->getParameter('charset'));
 414             } elseif ($use_iframe) {
 415                 /**
 416                  * If we don't add html message between iframe tags,
 417                  * we must detect unsafe images and modify $has_unsafe_images.
 418                  */
 419                 $html_body = magicHTML($body, $id, $message, $mailbox);
 420                 // Convert character set in order to display html mails in different character set
 421                 $html_body = charset_decode($body_message->header->getParameter('charset'),$html_body,false,true);
 422
 423                 // creating iframe url
 424                 $iframeurl=sqm_baseuri().'src/view_html.php?'
 425                     . 'mailbox=' . $urlmailbox
 426                     . '&amp;passed_id=' . $id
 427                     . '&amp;ent_id=' . $ent_num
 428                     . '&amp;view_unsafe_images=' . (int) $view_unsafe_images;
 429
 430                 global $oTemplate;
 431                 $oTemplate->assign('iframe_url', $iframeurl);
 432                 $oTemplate->assign('iframe_height', $iframe_height);
 433                 $oTemplate->assign('html_body', $html_body);
 434
 435                 $body = $oTemplate->fetch('read_html_iframe.tpl');
 436             } else {
 437                 // old way of html rendering
 438                 /**
 439                  * convert character set. charset_decode does not remove html special chars
 440                  * applied by magicHTML functions and does not sanitize them second time if
 441                  * fourth argument is true.
 442                  */
 443                 $charset = $body_message->header->getParameter('charset');
 444                 if (!empty($charset)) {
 445                     $body = charset_decode($charset,$body,false,true);
 446                 }
 447                 $body = magicHTML($body, $id, $message, $mailbox);
 448             }
 449         } else {
 450             translateText($body, $wrap_at,
 451                     $body_message->header->getParameter('charset'));
 452         }
 453
 454         /*
 455          * Previously the links for downloading and unsafe images were printed
 456          * under the mail. By putting the links in a global variable we can
 457          * print it in the toolbar where it belongs. Since the original code was
 458          * in this place it's left here. It might be possible to move it to some
 459          * other place if that makes sense. The possibility to do so has not
 460          * been evaluated yet.
 461          */
 462
 463         // Initialize the global variable to an empty string.
 464         // FIXME: To have $download_and_unsafe_link as a global variable might not be needed since the use of separate variables ($download_href, $unsafe_image_toggle_href, and $unsafe_image_toggle_text) for the templates was introduced.
 465         $download_and_unsafe_link = '';
 466
 467         // Prepare and build a link for downloading the mail.
 468         $link = 'passed_id=' . $id . '&amp;ent_id='.$ent_num.
 469             '&amp;mailbox=' . $urlmailbox .'&amp;sort=' . $sort .
 470             '&amp;startMessage=' . $startMessage . '&amp;show_more=0';
 471         if (isset($passed_ent_id)) {
 472             $link .= '&amp;passed_ent_id='.$passed_ent_id;
 473         }
 474         $download_href = SM_PATH . 'src/download.php?absolute_dl=true&amp;' . $link;
 475
 476         // Always add the link for downloading the mail as a file to the global
 477         // variable.
 478         $download_and_unsafe_link .= "$nbsp|$nbsp"
 479             . create_hyperlink($download_href, _("Download this as a file"));
 480
 481         // Find out the right text to use in the link depending on the
 482         // circumstances. If the unsafe images are displayed the link should
 483         // hide them, if they aren't displayed the link should only appear if
 484         // the mail really contains unsafe images.
 485         if ($view_unsafe_images) {
 486             $text = _("Hide Unsafe Images");
 487         } else {
 488             if (isset($has_unsafe_images) && $has_unsafe_images) {
 489                 $link .= '&amp;view_unsafe_images=1';
 490                 $text = _("View Unsafe Images");
 491             } else {
 492                 $text = '';
 493             }
 494         }
 495
 496         // Only create a link for unsafe images if there's need for one. If so:
 497         // add it to the global variable.
 498         if($text != '') {
 499             $unsafe_image_toggle_href = SM_PATH . 'src/read_body.php?'.$link;
 500             $unsafe_image_toggle_text = $text;
 501             $download_and_unsafe_link .= "$nbsp|$nbsp"
 502                 . create_hyperlink($unsafe_image_toggle_href, $text);
 503         }
 504     }
 505     return $body;
 506 }
 507
 508 /**
 509  * Generate attachments array for passing to templates.
 510  *
 511  * @since 1.5.2
 512  * @param object $message SquirrelMail message object
 513  * @param array $exclude_id message parts that are not attachments.
 514  * @param string $mailbox mailbox name
 515  * @param integer $id message id
 516  */
 517 function buildAttachmentArray($message, $exclude_id, $mailbox, $id) {
 518     global $where, $what, $startMessage, $color, $passed_ent_id,
 519            $base_uri, $block_svg_download;
 520
 521     $att_ar = $message->getAttachments($exclude_id);
 522     $urlMailbox = urlencode($mailbox);
 523
 524     $attachments = array();
 525     foreach ($att_ar as $att) {
 526         $ent = $att->entity_id;
 527         $header = $att->header;
 528         $type0 = strtolower($header->type0);
 529         $type1 = strtolower($header->type1);
 530         if ($block_svg_download && strpos($type1, 'svg') === 0)
 531             continue;
 532
 533         $name = '';
 534         $links = array();
 535         $links['download link']['text'] = _("Download");
 536         $links['download link']['href'] = $base_uri .
 537             "src/download.php?absolute_dl=true&amp;passed_id=$id&amp;mailbox=$urlMailbox&amp;ent_id=$ent";
 538
 539         if ($type0 =='message' && $type1 == 'rfc822') {
 540             $default_page = $base_uri  . 'src/read_body.php';
 541             $rfc822_header = $att->rfc822_header;
 542             $filename = $rfc822_header->subject;
 543             if (trim( $filename ) == '') {
 544                 $filename = 'untitled-[' . $ent . ']' ;
 545             }
 546             $from_o = $rfc822_header->from;
 547             if (is_object($from_o)) {
 548                 $from_name = decodeHeader($from_o->getAddress(false));
 549             } elseif (is_array($from_o) && count($from_o) && is_object($from_o[0])) {
 550                 // something weird happens when a digest message is opened and you return to the digest
 551                 // now the from object is part of an array. Probably the parseHeader call overwrites the info
 552                 // retrieved from the bodystructure in a different way. We need to fix this later.
 553                 // possible starting point, do not fetch header we already have and inspect how
 554                 // the rfc822_header object behaves.
 555                 $from_name = decodeHeader($from_o[0]->getAddress(false));
 556             } else {
 557                 $from_name = _("Unknown sender");
 558             }
 559             $description = _("From").': '.$from_name;
 560         } else {
 561             $default_page = $base_uri  . 'src/download.php';
 562             $filename = $att->getFilename();
 563             if ($header->description) {
 564                 $description = decodeHeader($header->description);
 565             } else {
 566                 $description = '';
 567             }
 568         }
 569
 570         $display_filename = $filename;
 571         if (isset($passed_ent_id)) {
 572             $passed_ent_id_link = '&amp;passed_ent_id='.$passed_ent_id;
 573         } else {
 574             $passed_ent_id_link = '';
 575         }
 576         $defaultlink = $default_page . "?startMessage=$startMessage"
 577             . "&amp;passed_id=$id&amp;mailbox=$urlMailbox"
 578             . '&amp;ent_id='.$ent.$passed_ent_id_link;
 579         if ($where && $what) {
 580             $defaultlink .= '&amp;where='. urlencode($where).'&amp;what='.urlencode($what);
 581         }
 582         // IE does make use of mime content sniffing. Forcing a download
 583         // prohibit execution of XSS inside an application/octet-stream attachment
 584         if ($type0 == 'application' && $type1 == 'octet-stream') {
 585             $defaultlink .= '&amp;absolute_dl=true';
 586         }
 587
 588         /* This executes the attachment hook with a specific MIME-type.
 589          * It also allows plugins to run if there's a rule for a more
 590          * generic type. Finally, a hook for ALL attachment types is
 591          * run as well.
 592          */
 593         // First remember the default link.
 594         $defaultlink_orig = $defaultlink;
 595
 596         /* The API for this hook has changed as of 1.5.2 so that all plugin
 597            arguments are passed in an array instead of each their own plugin
 598            argument, and arguments are passed by reference, so instead of
 599            returning any changes, changes should simply be made to the original
 600            arguments themselves. */
 601         $temp = array(&$links, &$startMessage, &$id, &$urlMailbox, &$ent,
 602                     &$defaultlink, &$display_filename, &$where, &$what,
 603                     &$type0, &$type1);
 604         do_hook("attachment $type0/$type1", $temp);
 605         /* The API for this hook has changed as of 1.5.2 so that all plugin
 606            arguments are passed in an array instead of each their own plugin
 607            argument, and arguments are passed by reference, so instead of
 608            returning any changes, changes should simply be made to the original
 609            arguments themselves. */
 610         $temp = array(&$links, &$startMessage, &$id, &$urlMailbox, &$ent,
 611                       &$defaultlink, &$display_filename, &$where, &$what,
 612                       &$type0, &$type1);
 613         // Do not let a generic plugin change the default link if a more
 614         // specialized one already did it...
 615         if ($defaultlink != $defaultlink_orig) {
 616             $dummy = '';
 617             $temp[5] = &$dummy;
 618         }
 619         do_hook("attachment $type0/*", $temp);
 620         /* The API for this hook has changed as of 1.5.2 so that all plugin
 621            arguments are passed in an array instead of each their own plugin
 622            argument, and arguments are passed by reference, so instead of
 623            returning any changes, changes should simply be made to the original
 624            arguments themselves. */
 625         $temp = array(&$links, &$startMessage, &$id, &$urlMailbox, &$ent,
 626                       &$defaultlink, &$display_filename, &$where, &$what,
 627                       &$type0, &$type1);
 628         // Do not let a generic plugin change the default link if a more
 629         // specialized one already did it...
 630         if ($defaultlink != $defaultlink_orig) {
 631             $dummy = '';
 632             $temp[5] = &$dummy;
 633         }
 634         do_hook("attachment */*", $temp);
 635
 636         $this_attachment = array();
 637         $this_attachment['Name'] = decodeHeader($display_filename);
 638         $this_attachment['Description'] = $description;
 639         $this_attachment['DefaultHREF'] = $defaultlink;
 640         $this_attachment['DownloadHREF'] = $links['download link']['href'];
 641         $this_attachment['ViewHREF'] = isset($links['attachment_common']) ? $links['attachment_common']['href'] : '';
 642
 643         // base64 encoded file sizes are misleading, so approximate real size
 644         if (!empty($header->encoding) && strtolower($header->encoding) == 'base64')
 645             $this_attachment['Size'] = $header->size / 4 * 3;
 646         else
 647             $this_attachment['Size'] = $header->size;
 648
 649         $this_attachment['ContentType'] = sm_encode_html_special_chars($type0 .'/'. $type1);
 650         $this_attachment['OtherLinks'] = array();
 651         foreach ($links as $val) {
 652             if ($val['text']==_("Download")) {
 653                 $this_attachment['DownloadHREF'] = $val['href'];
 654                 continue;
 655             }
 656             if ($val['text']==_("View")) {
 657                 $this_attachment['ViewHREF'] = $val['href'];
 658                 continue;
 659             }
 660
 661             // This makes no sense - If 'text' and 'extra' are just concatenated,
 662             // there is no point in having 'extra'.... I am going to assume this
 663             // was a mistake and am changing 'extra' to be what I think it was
 664             // meant to be: additional tag attributes.  However, I'm not checking
 665             // extensively for plugins that were using this the wrong way (but why would they?)
 666             if (empty($val['text']))
 667                 continue;
 668
 669             $temp = array();
 670             $temp['HREF'] = $val['href'];
 671             $temp['Text'] = $val['text'];
 672             $temp['Extra'] = (empty($val['extra']) ? '' : $val['extra']);
 673             $this_attachment['OtherLinks'][] = $temp;
 674         }
 675         $attachments[] = $this_attachment;
 676
 677         unset($links);
 678     }
 679
 680     return $attachments;
 681 }
 682
 683 /**
 684  * Displays attachment links and information
 685  *
 686  * Since 1.3.0 function is not included in formatBody() call.
 687  *
 688  * Since 1.0.2 uses attachment $type0/$type1 hook.
 689  * Since 1.2.5 uses attachment $type0/* hook.
 690  * Since 1.5.0 uses attachments_bottom hook.
 691  * Since 1.5.2 uses templates and does *not* return a value.
 692  *
 693  * @param object $message SquirrelMail message object
 694  * @param array $exclude_id message parts that are not attachments.
 695  * @param string $mailbox mailbox name
 696  * @param integer $id message id
 697  */
 698 function formatAttachments($message, $exclude_id, $mailbox, $id) {
 699     global $oTemplate;
 700
 701     $attach = buildAttachmentArray($message, $exclude_id, $mailbox, $id);
 702
 703     $oTemplate->assign('attachments', $attach);
 704     $oTemplate->display('read_attachments.tpl');
 705 }
 706
 707 function sqimap_base64_decode(&$string) {
 708
 709     // Base64 encoded data goes in pairs of 4 bytes. To achieve on the
 710     // fly decoding (to reduce memory usage) you have to check if the
 711     // data has incomplete pairs
 712
 713     // Remove the noise in order to check if the 4 bytes pairs are complete
 714     $string = str_replace(array("\r\n","\n", "\r", " "),array('','','',''),$string);
 715
 716     $sStringRem = '';
 717     $iMod = strlen($string) % 4;
 718     if ($iMod) {
 719         $sStringRem = substr($string,-$iMod);
 720         // Check if $sStringRem contains padding characters
 721         if (substr($sStringRem,-1) != '=') {
 722             $string = substr($string,0,-$iMod);
 723         } else {
 724             $sStringRem = '';
 725         }
 726     }
 727     $string = base64_decode($string);
 728     return $sStringRem;
 729 }
 730
 731 /**
 732  * Decodes encoded string (usually message body)
 733  *
 734  * This function decodes a string (usually the message body)
 735  * depending on the encoding type.  Currently quoted-printable
 736  * and base64 encodings are supported.
 737  *
 738  * The decode_body hook was added to this function in 1.4.2/1.5.0.
 739  * The $force_crlf parameter was added in 1.5.2.
 740  *
 741  * @param string $string     The encoded string
 742  * @param string $encoding   used encoding
 743  * @param string $force_crlf Whether or not to force CRLF or LF
 744  *                           line endings (or to leave as is).
 745  *                           If given as "LF", line endings will
 746  *                           all be converted to LF; if "CRLF",
 747  *                           line endings will all be converted
 748  *                           to CRLF.  If given as an empty value,
 749  *                           the global $force_crlf_default will
 750  *                           be consulted (it can be specified in
 751  *                           config/config_local.php).  Otherwise,
 752  *                           any other value will cause the string
 753  *                           to be left alone.  Note that this will
 754  *                           be overridden to "LF" if not using at
 755  *                           least PHP version 4.3.0. (OPTIONAL;
 756  *                           default is empty - consult global
 757  *                           default value)
 758  *
 759  * @return string The decoded string
 760  *
 761  * @since 1.0
 762  *
 763  */
 764 function decodeBody($string, $encoding, $force_crlf='') {
 765
 766     global $force_crlf_default;
 767     if (empty($force_crlf)) $force_crlf = $force_crlf_default;
 768     $force_crlf = strtoupper($force_crlf);
 769
 770     // must force line endings to LF due to broken
 771     // quoted_printable_decode() in PHP versions
 772     // before 4.3.0 (see below)
 773     //
 774     if (!check_php_version(4, 3, 0) || $force_crlf == 'LF')
 775         $string = str_replace("\r\n", "\n", $string);
 776     else if ($force_crlf == 'CRLF')
 777         $string = str_replace("\n", "\r\n", $string);
 778
 779     $encoding = strtolower($encoding);
 780
 781     $encoding_handler = do_hook('decode_body', $encoding);
 782
 783
 784     // plugins get first shot at decoding the string
 785     //
 786     if (!empty($encoding_handler) && function_exists($encoding_handler)) {
 787         $string = $encoding_handler('decode', $string);
 788
 789     } elseif ($encoding == 'quoted-printable' ||
 790             $encoding == 'quoted_printable') {
 791
 792         // quoted_printable_decode() function is broken in older
 793         // php versions.  Text with \r\n decoding was fixed only
 794         // in php 4.3.0.  Minimal code requirement is PHP 4.0.4+
 795         // and the above call to:  str_replace("\r\n", "\n", $string);
 796         //
 797         $string = quoted_printable_decode($string);
 798
 799     } elseif ($encoding == 'base64') {
 800         $string = base64_decode($string);
 801     }
 802
 803     // All other encodings are returned raw.
 804     return $string;
 805 }
 806
 807 /**
 808  * Decodes headers
 809  *
 810  * This function decodes strings that are encoded according to
 811  * RFC1522 (MIME Part Two: Message Header Extensions for Non-ASCII Text).
 812  * Patched by Christian Schmidt <christian@ostenfeld.dk>  23/03/2002
 813  *
 814  * @param string $string header string that has to be made readable
 815  * @param boolean $utfencode change message in order to be readable on user's charset. defaults to true
 816  * @param boolean $htmlsafe preserve spaces and sanitize html special characters. defaults to true
 817  * @param boolean $decide decide if string can be utfencoded. defaults to false
 818  * @return string decoded header string
 819  */
 820 function decodeHeader ($string, $utfencode=true,$htmlsafe=true,$decide=false) {
 821     global $languages, $squirrelmail_language,$default_charset, $fix_broken_base64_encoded_messages;
 822     if (is_array($string)) {
 823         $string = implode("\n", $string);
 824     }
 825
 826     if (isset($languages[$squirrelmail_language]['XTRA_CODE']) &&
 827             function_exists($languages[$squirrelmail_language]['XTRA_CODE'] . '_decodeheader')) {
 828         $string = call_user_func($languages[$squirrelmail_language]['XTRA_CODE'] . '_decodeheader', $string);
 829         // Do we need to return at this point?
 830         // return $string;
 831     }
 832     $i = 0;
 833     $iLastMatch = -2;
 834     $encoded = true;
 835
 836 // FIXME: spaces are allowed inside quoted-printable encoding, but the following line will bust up any such encoded strings
 837     $aString = explode(' ',$string);
 838     $ret = '';
 839     foreach ($aString as $chunk) {
 840         if ($encoded && $chunk === '') {
 841             continue;
 842         } elseif ($chunk === '') {
 843             $ret .= ' ';
 844             continue;
 845         }
 846         $encoded = false;
 847         /* if encoded words are not separated by a linear-space-white we still catch them */
 848         $j = $i-1;
 849
 850         while ($match = preg_match('/^(.*)=\?([^?]*)\?(Q|B)\?([^?]*)\?=(.*)$/Ui',$chunk,$res)) {
 851             /* if the last chunk isn't an encoded string then put back the space, otherwise don't */
 852             if ($iLastMatch !== $j) {
 853                 if ($htmlsafe) {
 854                     $ret .= '&#32;';
 855                 } else {
 856                     $ret .= ' ';
 857                 }
 858             }
 859             $iLastMatch = $i;
 860             $j = $i;
 861             if ($htmlsafe) {
 862                 $ret .= sm_encode_html_special_chars($res[1]);
 863             } else {
 864                 $ret .= $res[1];
 865             }
 866             $encoding = ucfirst($res[3]);
 867
 868             /* decide about valid decoding */
 869             if ($decide && is_conversion_safe($res[2])) {
 870                 $utfencode=true;
 871                 $can_be_encoded=true;
 872             } else {
 873                 $can_be_encoded=false;
 874             }
 875             switch ($encoding)
 876             {
 877                 case 'B':
 878                     // fix broken base64-encoded strings (remove end = padding,
 879                     // change any = to + in middle of string, add padding back
 880                     // to the end)
 881                     if ($fix_broken_base64_encoded_messages) {
 882                         $encoded_string_minus_padding = strtr(rtrim($res[4], '='), '=', '+');
 883                         $res[4] = str_pad($encoded_string_minus_padding, strlen($res[4]), '=');
 884                     }
 885                     $replace = base64_decode($res[4]);
 886                     if ($utfencode) {
 887                         if ($can_be_encoded) {
 888                             /* convert string to different charset,
 889                              * if functions asks for it (usually in compose)
 890                              */
 891                             $ret .= charset_convert($res[2],$replace,$default_charset,$htmlsafe);
 892                         } else {
 893                             // convert string to html codes in order to display it
 894                             $ret .= charset_decode($res[2],$replace);
 895                         }
 896                     } else {
 897                         if ($htmlsafe) {
 898                             $replace = sm_encode_html_special_chars($replace);
 899                         }
 900                         $ret.= $replace;
 901                     }
 902                     break;
 903                 case 'Q':
 904                     $replace = str_replace('_', ' ', $res[4]);
 905                     $replace = preg_replace_callback('/=([0-9a-f]{2})/i',
 906                                              (check_php_version(5, 3, 0)
 907                                               ? function($matches) { return chr(hexdec($matches[1])); }
 908                                               : create_function ('$matches', 'return chr(hexdec($matches[1]));')
 909                                              ),
 910                                              $replace);
 911                     if ($utfencode) {
 912                         if ($can_be_encoded) {
 913                             /* convert string to different charset,
 914                              * if functions asks for it (usually in compose)
 915                              */
 916                             $replace = charset_convert($res[2], $replace,$default_charset,$htmlsafe);
 917                         } else {
 918                             // convert string to html codes in order to display it
 919                             $replace = charset_decode($res[2], $replace);
 920                         }
 921                     } else {
 922                         if ($htmlsafe) {
 923                             $replace = sm_encode_html_special_chars($replace);
 924                         }
 925                     }
 926                     $ret .= $replace;
 927                     break;
 928                 default:
 929                     break;
 930             }
 931             $chunk = $res[5];
 932             $encoded = true;
 933         }
 934         if (!$encoded) {
 935             if ($htmlsafe) {
 936                 $ret .= '&#32;';
 937             } else {
 938                 $ret .= ' ';
 939             }
 940         }
 941
 942         if (!$encoded && $htmlsafe) {
 943             $ret .= sm_encode_html_special_chars($chunk);
 944         } else {
 945             $ret .= $chunk;
 946         }
 947         ++$i;
 948     }
 949     /* remove the first added space */
 950     if ($ret) {
 951         if ($htmlsafe) {
 952             $ret = substr($ret,5);
 953         } else {
 954             $ret = substr($ret,1);
 955         }
 956     }
 957
 958     return $ret;
 959 }
 960
 961 /**
 962  * Encodes header
 963  *
 964  * Function uses XTRA_CODE _encodeheader function, if such function exists.
 965  *
 966  * Function uses Q encoding by default and encodes a string according to RFC
 967  * 1522 for use in headers if it contains 8-bit characters or anything that
 968  * looks like it should be encoded.
 969  *
 970  * Function switches to B encoding and encodeHeaderBase64() function, if
 971  * string is 8bit and multibyte character set supported by mbstring extension
 972  * is used. It can cause E_USER_NOTICE errors, if interface is used with
 973  * multibyte character set unsupported by mbstring extension.
 974  *
 975  * @param string $string header string, that has to be encoded
 976  * @return string quoted-printable encoded string
 977  * @todo make $mb_charsets system wide constant
 978  */
 979 function encodeHeader ($string) {
 980     global $default_charset, $languages, $squirrelmail_language;
 981
 982     if (isset($languages[$squirrelmail_language]['XTRA_CODE']) &&
 983             function_exists($languages[$squirrelmail_language]['XTRA_CODE'] . '_encodeheader')) {
 984         return  call_user_func($languages[$squirrelmail_language]['XTRA_CODE'] . '_encodeheader', $string);
 985     }
 986
 987     // Use B encoding for multibyte charsets
 988     $mb_charsets = array('utf-8','big5','gb2313','euc-kr');
 989     if (in_array($default_charset,$mb_charsets) &&
 990         in_array($default_charset,sq_mb_list_encodings()) &&
 991         sq_is8bit($string)) {
 992         return encodeHeaderBase64($string,$default_charset);
 993     } elseif (in_array($default_charset,$mb_charsets) &&
 994               sq_is8bit($string) &&
 995               ! in_array($default_charset,sq_mb_list_encodings())) {
 996         // Add E_USER_NOTICE error here (can cause 'Cannot add header information' warning in compose.php)
 997         // trigger_error('encodeHeader: Multibyte character set unsupported by mbstring extension.',E_USER_NOTICE);
 998     }
 999
1000     // Encode only if the string contains 8-bit characters or =?
1001     $j = strlen($string);
1002     $max_l = 75 - strlen($default_charset) - 7;
1003     $aRet = array();
1004     $ret = '';
1005     $iEncStart = $enc_init = false;
1006     $cur_l = $iOffset = 0;
1007     for($i = 0; $i < $j; ++$i) {
1008         switch($string[$i])
1009         {
1010             case '"':
1011             case '=':
1012             case '<':
1013             case '>':
1014             case ',':
1015             case '?':
1016             case '_':
1017                 if ($iEncStart === false) {
1018                     $iEncStart = $i;
1019                 }
1020                 $cur_l+=3;
1021                 if ($cur_l > ($max_l-2)) {
1022                     /* if there is an stringpart that doesn't need encoding, add it */
1023                     $aRet[] = substr($string,$iOffset,$iEncStart-$iOffset);
1024                     $aRet[] = "=?$default_charset?Q?$ret?=";
1025                     $iOffset = $i;
1026                     $cur_l = 0;
1027                     $ret = '';
1028                     $iEncStart = false;
1029                 } else {
1030                     $ret .= sprintf("=%02X",ord($string[$i]));
1031                 }
1032                 break;
1033             case '(':
1034             case ')':
1035                 if ($iEncStart !== false) {
1036                     $aRet[] = substr($string,$iOffset,$iEncStart-$iOffset);
1037                     $aRet[] = "=?$default_charset?Q?$ret?=";
1038                     $iOffset = $i;
1039                     $cur_l = 0;
1040                     $ret = '';
1041                     $iEncStart = false;
1042                 }
1043                 break;
1044             case ' ':
1045                 if ($iEncStart !== false) {
1046                     $cur_l++;
1047                     if ($cur_l > $max_l) {
1048                         $aRet[] = substr($string,$iOffset,$iEncStart-$iOffset);
1049                         $aRet[] = "=?$default_charset?Q?$ret?=";
1050                         $iOffset = $i;
1051                         $cur_l = 0;
1052                         $ret = '';
1053                         $iEncStart = false;
1054                     } else {
1055                         $ret .= '_';
1056                     }
1057                 }
1058                 break;
1059             default:
1060                 $k = ord($string[$i]);
1061                 if ($k > 126) {
1062                     if ($iEncStart === false) {
1063                         // do not start encoding in the middle of a string, also take the rest of the word.
1064                         $sLeadString = substr($string,0,$i);
1065                         $aLeadString = explode(' ',$sLeadString);
1066                         $sToBeEncoded = array_pop($aLeadString);
1067                         $iEncStart = $i - strlen($sToBeEncoded);
1068                         $ret .= $sToBeEncoded;
1069                         $cur_l += strlen($sToBeEncoded);
1070                     }
1071                     $cur_l += 3;
1072                     /* first we add the encoded string that reached it's max size */
1073                     if ($cur_l > ($max_l-2)) {
1074                         $aRet[] = substr($string,$iOffset,$iEncStart-$iOffset);
1075                         $aRet[] = "=?$default_charset?Q?$ret?= "; /* the next part is also encoded => separate by space */
1076                         $cur_l = 3;
1077                         $ret = '';
1078                         $iOffset = $i;
1079                         $iEncStart = $i;
1080                     }
1081                     $enc_init = true;
1082                     $ret .= sprintf("=%02X", $k);
1083                 } else {
1084                     if ($iEncStart !== false) {
1085                         $cur_l++;
1086                         if ($cur_l > $max_l) {
1087                             $aRet[] = substr($string,$iOffset,$iEncStart-$iOffset);
1088                             $aRet[] = "=?$default_charset?Q?$ret?=";
1089                             $iEncStart = false;
1090                             $iOffset = $i;
1091                             $cur_l = 0;
1092                             $ret = '';
1093                         } else {
1094                             $ret .= $string[$i];
1095                         }
1096                     }
1097                 }
1098                 break;
1099         }
1100     }
1101
1102     if ($enc_init) {
1103         if ($iEncStart !== false) {
1104             $aRet[] = substr($string,$iOffset,$iEncStart-$iOffset);
1105             $aRet[] = "=?$default_charset?Q?$ret?=";
1106         } else {
1107             $aRet[] = substr($string,$iOffset);
1108         }
1109         $string = implode('',$aRet);
1110     }
1111     return $string;
1112 }
1113
1114 /**
1115  * Encodes string according to rfc2047 B encoding header formating rules
1116  *
1117  * It is recommended way to encode headers with character sets that store
1118  * symbols in more than one byte.
1119  *
1120  * Function requires mbstring support. If required mbstring functions are missing,
1121  * function returns false and sets E_USER_WARNING level error message.
1122  *
1123  * Minimal requirements - php 4.0.6 with mbstring extension. Please note,
1124  * that mbstring functions will generate E_WARNING errors, if unsupported
1125  * character set is used. mb_encode_mimeheader function provided by php
1126  * mbstring extension is not used in order to get better control of header
1127  * encoding.
1128  *
1129  * Used php code functions - function_exists(), trigger_error(), strlen()
1130  * (is used with charset names and base64 strings). Used php mbstring
1131  * functions - mb_strlen and mb_substr.
1132  *
1133  * Related documents: rfc 2045 (BASE64 encoding), rfc 2047 (mime header
1134  * encoding), rfc 2822 (header folding)
1135  *
1136  * @param string $string header string that must be encoded
1137  * @param string $charset character set. Must be supported by mbstring extension.
1138  * Use sq_mb_list_encodings() to detect supported charsets.
1139  * @return string string encoded according to rfc2047 B encoding formating rules
1140  * @since 1.5.1
1141  * @todo First header line can be wrapped to $iMaxLength - $HeaderFieldLength - 1
1142  * @todo Do we want to control max length of header?
1143  * @todo Do we want to control EOL (end-of-line) marker?
1144  * @todo Do we want to translate error message?
1145  */
1146 function encodeHeaderBase64($string,$charset) {
1147     /**
1148      * Check mbstring function requirements.
1149      */
1150     if (! function_exists('mb_strlen') ||
1151         ! function_exists('mb_substr')) {
1152         // set E_USER_WARNING
1153         trigger_error('encodeHeaderBase64: Required mbstring functions are missing.',E_USER_WARNING);
1154         // return false
1155         return false;
1156     }
1157
1158     // initial return array
1159     $aRet = array();
1160
1161     /**
1162      * header length = 75 symbols max (same as in encodeHeader)
1163      * remove $charset length
1164      * remove =? ? ?= (5 chars)
1165      * remove 2 more chars (\r\n ?)
1166      */
1167     $iMaxLength = 75 - strlen($charset) - 7;
1168
1169     // set first character position
1170     $iStartCharNum = 0;
1171
1172     // loop through all characters. count characters and not bytes.
1173     for ($iCharNum=1; $iCharNum<=mb_strlen($string,$charset); $iCharNum++) {
1174         // encode string from starting character to current character.
1175         $encoded_string = base64_encode(mb_substr($string,$iStartCharNum,$iCharNum-$iStartCharNum,$charset));
1176
1177         // Check encoded string length
1178         if(strlen($encoded_string)>$iMaxLength) {
1179             // if string exceeds max length, reduce number of encoded characters and add encoded string part to array
1180             $aRet[] = base64_encode(mb_substr($string,$iStartCharNum,$iCharNum-$iStartCharNum-1,$charset));
1181
1182             // set new starting character
1183             $iStartCharNum = $iCharNum-1;
1184
1185             // encode last char (in case it is last character in string)
1186             $encoded_string = base64_encode(mb_substr($string,$iStartCharNum,$iCharNum-$iStartCharNum,$charset));
1187         } // if string is shorter than max length - add next character
1188     }
1189
1190     // add last encoded string to array
1191     $aRet[] = $encoded_string;
1192
1193     // set initial return string
1194     $sRet = '';
1195
1196     // loop through encoded strings
1197     foreach($aRet as $string) {
1198         // TODO: Do we want to control EOL (end-of-line) marker
1199         if ($sRet!='') $sRet.= " ";
1200
1201         // add header tags and encoded string to return string
1202         $sRet.= '=?'.$charset.'?B?'.$string.'?=';
1203     }
1204
1205     return $sRet;
1206 }
1207
1208 /* This function trys to locate the entity_id of a specific mime element */
1209 function find_ent_id($id, $message) {
1210     for ($i = 0, $ret = ''; $ret == '' && $i < count($message->entities); $i++) {
1211         if ($message->entities[$i]->header->type0 == 'multipart')  {
1212             $ret = find_ent_id($id, $message->entities[$i]);
1213         } else {
1214             if (strcasecmp($message->entities[$i]->header->id, $id) == 0) {
1215 //                if (sq_check_save_extension($message->entities[$i])) {
1216                 return $message->entities[$i]->entity_id;
1217 //                }
1218             } elseif (!empty($message->entities[$i]->header->parameters['name'])) {
1219                 /**
1220                  * This is part of a fix for Outlook Express 6.x generating
1221                  * cid URLs without creating content-id headers
1222                  * @@JA - 20050207
1223                  */
1224                 if (strcasecmp($message->entities[$i]->header->parameters['name'], $id) == 0) {
1225                     return $message->entities[$i]->entity_id;
1226                 }
1227             }
1228         }
1229     }
1230     return $ret;
1231 }
1232
1233 function sq_check_save_extension($message) {
1234     $filename = $message->getFilename();
1235     $ext = substr($filename, strrpos($filename,'.')+1);
1236     $save_extensions = array('jpg','jpeg','gif','png','bmp');
1237     return in_array($ext, $save_extensions);
1238 }
1239
1240
1241 /**
1242  ** HTMLFILTER ROUTINES
1243  */
1244
1245 /**
1246  * This function checks attribute values for entity-encoded values
1247  * and returns them translated into 8-bit strings so we can run
1248  * checks on them.
1249  *
1250  * @param  $attvalue A string to run entity check against.
1251  * @return           Nothing, modifies a reference value.
1252  */
1253 function sq_defang(&$attvalue){
1254     $me = 'sq_defang';
1255     /**
1256      * Skip this if there aren't ampersands or backslashes.
1257      */
1258     if (strpos($attvalue, '&') === false
1259         && strpos($attvalue, '\\') === false){
1260         return;
1261     }
1262     $m = false;
1263     // before deent, translate the dangerous unicode characters and ... to safe values
1264     // otherwise the regular expressions do not match.
1265
1266
1267
1268     do {
1269         $m = false;
1270         $m = $m || sq_deent($attvalue, '/\&#0*(\d+);*/s');
1271         $m = $m || sq_deent($attvalue, '/\&#x0*((\d|[a-f])+);*/si', true);
1272         $m = $m || sq_deent($attvalue, '/\\\\(\d+)/s', true);
1273     } while ($m == true);
1274     $attvalue = stripslashes($attvalue);
1275 }
1276
1277 /**
1278  * Kill any tabs, newlines, or carriage returns. Our friends the
1279  * makers of the browser with 95% market value decided that it'd
1280  * be funny to make "java[tab]script" be just as good as "javascript".
1281  *
1282  * @param  attvalue  The attribute value before extraneous spaces removed.
1283  * @return attvalue  Nothing, modifies a reference value.
1284  */
1285 function sq_unspace(&$attvalue){
1286     $me = 'sq_unspace';
1287     if (strcspn($attvalue, "\t\r\n\0 ") != strlen($attvalue)){
1288         $attvalue = str_replace(Array("\t", "\r", "\n", "\0", " "),
1289                                 Array('',   '',   '',   '',   ''), $attvalue);
1290     }
1291 }
1292
1293 /**
1294  * Translate all dangerous Unicode or Shift_JIS characters which are accepted by
1295  * IE as regular characters.
1296  *
1297  * @param  attvalue  The attribute value before dangerous characters are translated.
1298  * @return attvalue  Nothing, modifies a reference value.
1299  * @author Marc Groot Koerkamp.
1300  */
1301 function sq_fixIE_idiocy(&$attvalue) {
1302     // remove NUL
1303     $attvalue = str_replace("\0", "", $attvalue);
1304     // remove comments
1305     $attvalue = preg_replace("/(\/\*.*?\*\/)/","",$attvalue);
1306
1307     // IE has the evil habit of accepting every possible value for the attribute expression.
1308     // The table below contains characters which are parsed by IE if they are used in the "expression"
1309     // attribute value.
1310     $aDangerousCharsReplacementTable = array(
1311                         array('&#x029F;', '&#0671;' ,/* L UNICODE IPA Extension */
1312                               '&#x0280;', '&#0640;' ,/* R UNICODE IPA Extension */
1313                               '&#x0274;', '&#0628;' ,/* N UNICODE IPA Extension */
1314                               '&#xFF25;', '&#65317;' ,/* Unicode FULLWIDTH LATIN CAPITAL LETTER E */
1315                               '&#xFF45;', '&#65349;' ,/* Unicode FULLWIDTH LATIN SMALL LETTER E */
1316                               '&#xFF38;', '&#65336;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER X */
1317                               '&#xFF58;', '&#65368;',/* Unicode FULLWIDTH LATIN SMALL LETTER X */
1318                               '&#xFF30;', '&#65328;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER P */
1319                               '&#xFF50;', '&#65360;',/* Unicode FULLWIDTH LATIN SMALL LETTER P */
1320                               '&#xFF32;', '&#65330;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER R */
1321                               '&#xFF52;', '&#65362;',/* Unicode FULLWIDTH LATIN SMALL LETTER R */
1322                               '&#xFF33;', '&#65331;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER S */
1323                               '&#xFF53;', '&#65363;',/* Unicode FULLWIDTH LATIN SMALL LETTER S */
1324                               '&#xFF29;', '&#65321;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER I */
1325                               '&#xFF49;', '&#65353;',/* Unicode FULLWIDTH LATIN SMALL LETTER I */
1326                               '&#xFF2F;', '&#65327;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER O */
1327                               '&#xFF4F;', '&#65359;',/* Unicode FULLWIDTH LATIN SMALL LETTER O */
1328                               '&#xFF2E;', '&#65326;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER N */
1329                               '&#xFF4E;', '&#65358;',/* Unicode FULLWIDTH LATIN SMALL LETTER N */
1330                               '&#xFF2C;', '&#65324;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER L */
1331                               '&#xFF4C;', '&#65356;',/* Unicode FULLWIDTH LATIN SMALL LETTER L */
1332                               '&#xFF35;', '&#65333;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER U */
1333                               '&#xFF55;', '&#65365;',/* Unicode FULLWIDTH LATIN SMALL LETTER U */
1334                               '&#x207F;', '&#8319;' ,/* Unicode SUPERSCRIPT LATIN SMALL LETTER N */
1335                               "\xEF\xBC\xA5", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER E */   // in unicode this is some Chinese char range
1336                               "\xEF\xBD\x85", /* Shift JIS FULLWIDTH LATIN SMALL LETTER E */
1337                               "\xEF\xBC\xB8", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER X */
1338                               "\xEF\xBD\x98", /* Shift JIS FULLWIDTH LATIN SMALL LETTER X */
1339                               "\xEF\xBC\xB0", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER P */
1340                               "\xEF\xBD\x90", /* Shift JIS FULLWIDTH LATIN SMALL LETTER P */
1341                               "\xEF\xBC\xB2", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER R */
1342                               "\xEF\xBD\x92", /* Shift JIS FULLWIDTH LATIN SMALL LETTER R */
1343                               "\xEF\xBC\xB3", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER S */
1344                               "\xEF\xBD\x93", /* Shift JIS FULLWIDTH LATIN SMALL LETTER S */
1345                               "\xEF\xBC\xA9", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER I */
1346                               "\xEF\xBD\x89", /* Shift JIS FULLWIDTH LATIN SMALL LETTER I */
1347                               "\xEF\xBC\xAF", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER O */
1348                               "\xEF\xBD\x8F", /* Shift JIS FULLWIDTH LATIN SMALL LETTER O */
1349                               "\xEF\xBC\xAE", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER N */
1350                               "\xEF\xBD\x8E", /* Shift JIS FULLWIDTH LATIN SMALL LETTER N */
1351                               "\xEF\xBC\xAC", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER L */
1352                               "\xEF\xBD\x8C", /* Shift JIS FULLWIDTH LATIN SMALL LETTER L */
1353                               "\xEF\xBC\xB5", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER U */
1354                               "\xEF\xBD\x95", /* Shift JIS FULLWIDTH LATIN SMALL LETTER U */
1355                               "\xE2\x81\xBF", /* Shift JIS FULLWIDTH SUPERSCRIPT N */
1356                               "\xCA\x9F", /* L UNICODE IPA Extension */
1357                               "\xCA\x80", /* R UNICODE IPA Extension */
1358                               "\xC9\xB4"),  /* N UNICODE IPA Extension */
1359                        array('l', 'l', 'r','r','n','n',
1360                              'E','E','e','e','X','X','x','x','P','P','p','p','R','R','r','r','S','S','s','s','I','I',
1361                              'i','i','O','O','o','o','N','N','n','n','L','L','l','l','U','U','u','u','n','n',
1362                              'E','e','X','x','P','p','R','r','S','s','I','i','O','o','N','n','L','l','U','u','n','l','r','n'));
1363     $attvalue = str_replace($aDangerousCharsReplacementTable[0],$aDangerousCharsReplacementTable[1],$attvalue);
1364
1365     // Escapes are useful for special characters like "{}[]()'&. In other cases they are
1366     // used for XSS.
1367     $attvalue = preg_replace("/(\\\\)([a-zA-Z]{1})/",'$2',$attvalue);
1368 }
1369
1370 /**
1371  * This function returns the final tag out of the tag name, an array
1372  * of attributes, and the type of the tag. This function is called by
1373  * sq_sanitize internally.
1374  *
1375  * @param  $tagname  the name of the tag.
1376  * @param  $attary   the array of attributes and their values
1377  * @param  $tagtype  The type of the tag (see in comments).
1378  * @return           a string with the final tag representation.
1379  */
1380 function sq_tagprint($tagname, $attary, $tagtype){
1381     $me = 'sq_tagprint';
1382
1383     if ($tagtype == 2){
1384         $fulltag = '</' . $tagname . '>';
1385     } else {
1386         $fulltag = '<' . $tagname;
1387         if (is_array($attary) && sizeof($attary)){
1388             $atts = Array();
1389             foreach ($attary as $attname => $attvalue){
1390                 array_push($atts, "$attname=$attvalue");
1391             }
1392             $fulltag .= ' ' . join(" ", $atts);
1393         }
1394         if ($tagtype == 3){
1395             $fulltag .= ' /';
1396         }
1397         $fulltag .= '>';
1398     }
1399     return $fulltag;
1400 }
1401
1402 /**
1403  * A small helper function to use with array_walk. Modifies a by-ref
1404  * value and makes it lowercase.
1405  *
1406  * @param  $val a value passed by-ref.
1407  * @return      void since it modifies a by-ref value.
1408  */
1409 function sq_casenormalize(&$val){
1410     $val = strtolower($val);
1411 }
1412
1413 /**
1414  * This function skips any whitespace from the current position within
1415  * a string and to the next non-whitespace value.
1416  *
1417  * @param  $body   the string
1418  * @param  $offset the offset within the string where we should start
1419  *                 looking for the next non-whitespace character.
1420  * @return         the location within the $body where the next
1421  *                 non-whitespace char is located.
1422  */
1423 function sq_skipspace($body, $offset){
1424     $me = 'sq_skipspace';
1425     preg_match('/^(\s*)/s', substr($body, $offset), $matches);
1426     if (!empty($matches[1])){
1427         $offset += strlen($matches[1]);
1428     }
1429     return $offset;
1430 }
1431
1432 /**
1433  * This function looks for the next character within a string.  It's
1434  * really just a glorified "strpos", except it catches if failures
1435  * nicely.
1436  *
1437  * @param  $body   The string to look for needle in.
1438  * @param  $offset Start looking from this position.
1439  * @param  $needle The character/string to look for.
1440  * @return         location of the next occurance of the needle, or
1441  *                 strlen($body) if needle wasn't found.
1442  */
1443 function sq_findnxstr($body, $offset, $needle){
1444     $me  = 'sq_findnxstr';
1445     $pos = strpos($body, $needle, $offset);
1446     if ($pos === FALSE){
1447         $pos = strlen($body);
1448     }
1449     return $pos;
1450 }
1451
1452 /**
1453  * This function takes a PCRE-style regexp and tries to match it
1454  * within the string.
1455  *
1456  * @param  $body   The string to look for needle in.
1457  * @param  $offset Start looking from here.
1458  * @param  $reg    A PCRE-style regex to match.
1459  * @return         Returns a false if no matches found, or an array
1460  *                 with the following members:
1461  *                 - integer with the location of the match within $body
1462  *                 - string with whatever content between offset and the match
1463  *                 - string with whatever it is we matched
1464  */
1465 function sq_findnxreg($body, $offset, $reg){
1466     $me = 'sq_findnxreg';
1467     $matches = Array();
1468     $retarr = Array();
1469     preg_match("%^(.*?)($reg)%si", substr($body, $offset), $matches);
1470     if (!isset($matches[0]) || !$matches[0]){
1471         $retarr = false;
1472     } else {
1473         $retarr[0] = $offset + strlen($matches[1]);
1474         $retarr[1] = $matches[1];
1475         $retarr[2] = $matches[2];
1476     }
1477     return $retarr;
1478 }
1479
1480 /**
1481  * This function looks for the next tag.
1482  *
1483  * @param  $body   String where to look for the next tag.
1484  * @param  $offset Start looking from here.
1485  * @return         false if no more tags exist in the body, or
1486  *                 an array with the following members:
1487  *                 - string with the name of the tag
1488  *                 - array with attributes and their values
1489  *                 - integer with tag type (1, 2, or 3)
1490  *                 - integer where the tag starts (starting "<")
1491  *                 - integer where the tag ends (ending ">")
1492  *                 first three members will be false, if the tag is invalid.
1493  */
1494 function sq_getnxtag($body, $offset){
1495     $me = 'sq_getnxtag';
1496     if ($offset > strlen($body)){
1497         return false;
1498     }
1499     $lt = sq_findnxstr($body, $offset, "<");
1500     if ($lt == strlen($body)){
1501         return false;
1502     }
1503     /**
1504      * We are here:
1505      * blah blah <tag attribute="value">
1506      * \---------^
1507      */
1508     $pos = sq_skipspace($body, $lt+1);
1509     if ($pos >= strlen($body)){
1510         return Array(false, false, false, $lt, strlen($body));
1511     }
1512     /**
1513      * There are 3 kinds of tags:
1514      * 1. Opening tag, e.g.:
1515      *    <a href="blah">
1516      * 2. Closing tag, e.g.:
1517      *    </a>
1518      * 3. XHTML-style content-less tag, e.g.:
1519      *    <img src="blah" />
1520      */
1521     $tagtype = false;
1522     switch (substr($body, $pos, 1)){
1523         case '/':
1524             $tagtype = 2;
1525             $pos++;
1526             break;
1527         case '!':
1528             /**
1529              * A comment or an SGML declaration.
1530              */
1531             if (substr($body, $pos+1, 2) == "--"){
1532                 $gt = strpos($body, "-->", $pos);
1533                 if ($gt === false){
1534                     $gt = strlen($body);
1535                 } else {
1536                     $gt += 2;
1537                 }
1538                 return Array(false, false, false, $lt, $gt);
1539             } else {
1540                 $gt = sq_findnxstr($body, $pos, ">");
1541                 return Array(false, false, false, $lt, $gt);
1542             }
1543             break;
1544         default:
1545             /**
1546              * Assume tagtype 1 for now. If it's type 3, we'll switch values
1547              * later.
1548              */
1549             $tagtype = 1;
1550             break;
1551     }
1552
1553     $tag_start = $pos;
1554     $tagname = '';
1555     /**
1556      * Look for next [\W-_], which will indicate the end of the tag name.
1557      */
1558     $regary = sq_findnxreg($body, $pos, "[^\w\-_]");
1559     if ($regary == false){
1560         return Array(false, false, false, $lt, strlen($body));
1561     }
1562     list($pos, $tagname, $match) = $regary;
1563     $tagname = strtolower($tagname);
1564
1565     /**
1566      * $match can be either of these:
1567      * '>'  indicating the end of the tag entirely.
1568      * '\s' indicating the end of the tag name.
1569      * '/'  indicating that this is type-3 xhtml tag.
1570      *
1571      * Whatever else we find there indicates an invalid tag.
1572      */
1573     switch ($match){
1574         case '/':
1575             /**
1576              * This is an xhtml-style tag with a closing / at the
1577              * end, like so: <img src="blah" />. Check if it's followed
1578              * by the closing bracket. If not, then this tag is invalid
1579              */
1580             if (substr($body, $pos, 2) == "/>"){
1581                 $pos++;
1582                 $tagtype = 3;
1583             } else {
1584                 $gt = sq_findnxstr($body, $pos, ">");
1585                 $retary = Array(false, false, false, $lt, $gt);
1586                 return $retary;
1587             }
1588         case '>':
1589             return Array($tagname, false, $tagtype, $lt, $pos);
1590             break;
1591         default:
1592             /**
1593              * Check if it's whitespace
1594              */
1595             if (!preg_match('/\s/', $match)){
1596                 /**
1597                  * This is an invalid tag! Look for the next closing ">".
1598                  */
1599                 $gt = sq_findnxstr($body, $lt, ">");
1600                 return Array(false, false, false, $lt, $gt);
1601             }
1602             break;
1603     }
1604
1605     /**
1606      * At this point we're here:
1607      * <tagname  attribute='blah'>
1608      * \-------^
1609      *
1610      * At this point we loop in order to find all attributes.
1611      */
1612     $attname = '';
1613     $atttype = false;
1614     $attary = Array();
1615
1616     while ($pos <= strlen($body)){
1617         $pos = sq_skipspace($body, $pos);
1618         if ($pos == strlen($body)){
1619             /**
1620              * Non-closed tag.
1621              */
1622             return Array(false, false, false, $lt, $pos);
1623         }
1624         /**
1625          * See if we arrived at a ">" or "/>", which means that we reached
1626          * the end of the tag.
1627          */
1628         $matches = Array();
1629         if (preg_match("%^(\s*)(>|/>)%s", substr($body, $pos), $matches)) {
1630             /**
1631              * Yep. So we did.
1632              */
1633             $pos += strlen($matches[1]);
1634             if ($matches[2] == "/>"){
1635                 $tagtype = 3;
1636                 $pos++;
1637             }
1638             return Array($tagname, $attary, $tagtype, $lt, $pos);
1639         }
1640
1641         /**
1642          * There are several types of attributes, with optional
1643          * [:space:] between members.
1644          * Type 1:
1645          *   attrname[:space:]=[:space:]'CDATA'
1646          * Type 2:
1647          *   attrname[:space:]=[:space:]"CDATA"
1648          * Type 3:
1649          *   attr[:space:]=[:space:]CDATA
1650          * Type 4:
1651          *   attrname
1652          *
1653          * We leave types 1 and 2 the same, type 3 we check for
1654          * '"' and convert to "&quot" if needed, then wrap in
1655          * double quotes. Type 4 we convert into:
1656          * attrname="yes".
1657          */
1658         $regary = sq_findnxreg($body, $pos, "[^:\w\-_]");
1659         if ($regary == false){
1660             /**
1661              * Looks like body ended before the end of tag.
1662              */
1663             return Array(false, false, false, $lt, strlen($body));
1664         }
1665         list($pos, $attname, $match) = $regary;
1666         $attname = strtolower($attname);
1667         /**
1668          * We arrived at the end of attribute name. Several things possible
1669          * here:
1670          * '>'  means the end of the tag and this is attribute type 4
1671          * '/'  if followed by '>' means the same thing as above
1672          * '\s' means a lot of things -- look what it's followed by.
1673          *      anything else means the attribute is invalid.
1674          */
1675         switch($match){
1676             case '/':
1677                 /**
1678                  * This is an xhtml-style tag with a closing / at the
1679                  * end, like so: <img src="blah" />. Check if it's followed
1680                  * by the closing bracket. If not, then this tag is invalid
1681                  */
1682                 if (substr($body, $pos, 2) == "/>"){
1683                     $pos++;
1684                     $tagtype = 3;
1685                 } else {
1686                     $gt = sq_findnxstr($body, $pos, ">");
1687                     $retary = Array(false, false, false, $lt, $gt);
1688                     return $retary;
1689                 }
1690             case '>':
1691                 $attary[$attname] = '"yes"';
1692                 return Array($tagname, $attary, $tagtype, $lt, $pos);
1693                 break;
1694             default:
1695                 /**
1696                  * Skip whitespace and see what we arrive at.
1697                  */
1698                 $pos = sq_skipspace($body, $pos);
1699                 $char = substr($body, $pos, 1);
1700                 /**
1701                  * Two things are valid here:
1702                  * '=' means this is attribute type 1 2 or 3.
1703                  * \w means this was attribute type 4.
1704                  * anything else we ignore and re-loop. End of tag and
1705                  * invalid stuff will be caught by our checks at the beginning
1706                  * of the loop.
1707                  */
1708                 if ($char == "="){
1709                     $pos++;
1710                     $pos = sq_skipspace($body, $pos);
1711                     /**
1712                      * Here are 3 possibilities:
1713                      * "'"  attribute type 1
1714                      * '"'  attribute type 2
1715                      * everything else is the content of tag type 3
1716                      */
1717                     $quot = substr($body, $pos, 1);
1718                     if ($quot == "'"){
1719                         $regary = sq_findnxreg($body, $pos+1, "\'");
1720                         if ($regary == false){
1721                             return Array(false, false, false, $lt, strlen($body));
1722                         }
1723                         list($pos, $attval, $match) = $regary;
1724                         $pos++;
1725                         $attary[$attname] = "'" . $attval . "'";
1726                     } else if ($quot == '"'){
1727                         $regary = sq_findnxreg($body, $pos+1, '\"');
1728                         if ($regary == false){
1729                             return Array(false, false, false, $lt, strlen($body));
1730                         }
1731                         list($pos, $attval, $match) = $regary;
1732                         $pos++;
1733                         $attary[$attname] = '"' . $attval . '"';
1734                     } else {
1735                         /**
1736                          * These are hateful. Look for \s, or >.
1737                          */
1738                         $regary = sq_findnxreg($body, $pos, "[\s>]");
1739                         if ($regary == false){
1740                             return Array(false, false, false, $lt, strlen($body));
1741                         }
1742                         list($pos, $attval, $match) = $regary;
1743                         /**
1744                          * If it's ">" it will be caught at the top.
1745                          */
1746                         $attval = preg_replace("/\"/s", "&quot;", $attval);
1747                         $attary[$attname] = '"' . $attval . '"';
1748                     }
1749                 } else if (preg_match("|[\w/>]|", $char)) {
1750                     /**
1751                      * That was attribute type 4.
1752                      */
1753                     $attary[$attname] = '"yes"';
1754                 } else {
1755                     /**
1756                      * An illegal character. Find next '>' and return.
1757                      */
1758                     $gt = sq_findnxstr($body, $pos, ">");
1759                     return Array(false, false, false, $lt, $gt);
1760                 }
1761                 break;
1762         }
1763     }
1764     /**
1765      * The fact that we got here indicates that the tag end was never
1766      * found. Return invalid tag indication so it gets stripped.
1767      */
1768     return Array(false, false, false, $lt, strlen($body));
1769 }
1770
1771 /**
1772  * Translates entities into literal values so they can be checked.
1773  *
1774  * @param $attvalue the by-ref value to check.
1775  * @param $regex    the regular expression to check against.
1776  * @param $hex      whether the entites are hexadecimal.
1777  * @return          True or False depending on whether there were matches.
1778  */
1779 function sq_deent(&$attvalue, $regex, $hex=false){
1780     $me = 'sq_deent';
1781     $ret_match = false;
1782     // remove comments
1783     //$attvalue = preg_replace("/(\/\*.*\*\/)/","",$attvalue);
1784     preg_match_all($regex, $attvalue, $matches);
1785     if (is_array($matches) && sizeof($matches[0]) > 0){
1786         $repl = Array();
1787         for ($i = 0; $i < sizeof($matches[0]); $i++){
1788             $numval = $matches[1][$i];
1789             if ($hex){
1790                 $numval = hexdec($numval);
1791             }
1792             $repl[$matches[0][$i]] = chr($numval);
1793         }
1794         $attvalue = strtr($attvalue, $repl);
1795         return true;
1796     } else {
1797         return false;
1798     }
1799 }
1800
1801 /**
1802  * This function runs various checks against the attributes.
1803  *
1804  * @param  $tagname         String with the name of the tag.
1805  * @param  $attary          Array with all tag attributes.
1806  * @param  $rm_attnames     See description for sq_sanitize
1807  * @param  $bad_attvals     See description for sq_sanitize
1808  * @param  $add_attr_to_tag See description for sq_sanitize
1809  * @param  $message         message object
1810  * @param  $id              message id
1811  * @return                  Array with modified attributes.
1812  */
1813 function sq_fixatts($tagname,
1814                     $attary,
1815                     $rm_attnames,
1816                     $bad_attvals,
1817                     $add_attr_to_tag,
1818                     $message,
1819                     $id,
1820                     $mailbox
1821                     ){
1822     $me = 'sq_fixatts';
1823     foreach ($attary as $attname => $attvalue){
1824         /**
1825          * See if this attribute should be removed.
1826          */
1827         foreach ($rm_attnames as $matchtag=>$matchattrs){
1828             if (preg_match($matchtag, $tagname)){
1829                 foreach ($matchattrs as $matchattr){
1830                     if (preg_match($matchattr, $attname)){
1831                         unset($attary[$attname]);
1832                         continue;
1833                     }
1834                 }
1835             }
1836         }
1837         /**
1838          * Workaround for IE quirks
1839          */
1840         sq_fixIE_idiocy($attvalue);
1841
1842         /**
1843          * Remove any backslashes, entities, and extraneous whitespace.
1844          */
1845
1846         $oldattvalue = $attvalue;
1847         sq_defang($attvalue);
1848         if ($attname == 'style' && $attvalue !== $oldattvalue) {
1849             // entities are used in the attribute value. In 99% of the cases it's there as XSS
1850             // i.e.<div style="{ left:exp&#x0280;essio&#x0274;( alert('XSS') ) }">
1851             $attvalue = "idiocy";
1852             $attary[$attname] = $attvalue;
1853         }
1854         sq_unspace($attvalue);
1855
1856         /**
1857          * Now let's run checks on the attvalues.
1858          * I don't expect anyone to comprehend this. If you do,
1859          * get in touch with me so I can drive to where you live and
1860          * shake your hand personally. :)
1861          */
1862         foreach ($bad_attvals as $matchtag=>$matchattrs){
1863             if (preg_match($matchtag, $tagname)){
1864                 foreach ($matchattrs as $matchattr=>$valary){
1865                     if (preg_match($matchattr, $attname)){
1866                         /**
1867                          * There are two arrays in valary.
1868                          * First is matches.
1869                          * Second one is replacements
1870                          */
1871                         list($valmatch, $valrepl) = $valary;
1872                         $newvalue =
1873                             preg_replace($valmatch, $valrepl, $attvalue);
1874                         if ($newvalue != $attvalue){
1875                             $attary[$attname] = $newvalue;
1876                             $attvalue = $newvalue;
1877                         }
1878                     }
1879                 }
1880             }
1881         }
1882         if ($attname == 'style') {
1883             if (preg_match('/[\0-\37\200-\377]+/',$attvalue)) {
1884                 // 8bit and control characters in style attribute values can be used for XSS, remove them
1885                 $attary[$attname] = '"disallowed character"';
1886             }
1887             preg_match_all("/url\s*\((.+)\)/si",$attvalue,$aMatch);
1888             if (count($aMatch)) {
1889                 foreach($aMatch[1] as $sMatch) {
1890                     // url value
1891                     $urlvalue = $sMatch;
1892                     sq_fix_url($attname, $urlvalue, $message, $id, $mailbox,"'");
1893                     $attary[$attname] = str_replace($sMatch,$urlvalue,$attvalue);
1894                 }
1895             }
1896         }
1897         /**
1898          * Use white list based filtering on attributes which can contain url's
1899          */
1900         else if ($attname == 'href' || $attname == 'xlink:href' || $attname == 'src'
1901               || $attname == 'poster' || $attname == 'formaction'
1902               || $attname == 'background' || $attname == 'action') {
1903             sq_fix_url($attname, $attvalue, $message, $id, $mailbox);
1904             $attary[$attname] = $attvalue;
1905         }
1906     }
1907     /**
1908      * See if we need to append any attributes to this tag.
1909      */
1910     foreach ($add_attr_to_tag as $matchtag=>$addattary){
1911         if (preg_match($matchtag, $tagname)){
1912             $attary = array_merge($attary, $addattary);
1913         }
1914     }
1915     return $attary;
1916 }
1917
1918 /**
1919  * This function filters url's
1920  *
1921  * @param  $attvalue        String with attribute value to filter
1922  * @param  $message         message object
1923  * @param  $id               message id
1924  * @param  $mailbox         mailbox
1925  * @param  $sQuote          quoting characters around url's
1926  */
1927 function sq_fix_url($attname, &$attvalue, $message, $id, $mailbox,$sQuote = '"') {
1928     $attvalue = trim($attvalue);
1929     if ($attvalue && ($attvalue[0] =='"'|| $attvalue[0] == "'")) {
1930         // remove the double quotes
1931         $sQuote = $attvalue[0];
1932         $attvalue = trim(substr($attvalue,1,-1));
1933     }
1934
1935     // If there's no "view_unsafe_images" variable in the URL, turn unsafe
1936     // images off by default.
1937     sqgetGlobalVar('view_unsafe_images', $view_unsafe_images, SQ_GET, FALSE);
1938
1939     global $use_transparent_security_image;
1940     if ($use_transparent_security_image) $secremoveimg = '../images/spacer.png';
1941     else $secremoveimg = '../images/' . _("sec_remove_eng.png");
1942
1943     /**
1944      * Replace empty src tags with the blank image.  src is only used
1945      * for frames, images, and image inputs.  Doing a replace should
1946      * not affect them working as should be, however it will stop
1947      * IE from being kicked off when src for img tags are not set
1948      */
1949     if ($attvalue == '') {
1950         $attvalue = '"' . SM_PATH . 'images/blank.png"';
1951     } else {
1952         // first, disallow 8 bit characters and control characters
1953         if (preg_match('/[\0-\37\200-\377]+/',$attvalue)) {
1954             switch ($attname) {
1955                 case 'href':
1956                     $attvalue = $sQuote . 'http://invalid-stuff-detected.example.com' . $sQuote;
1957                     break;
1958                 default:
1959                     $attvalue = $sQuote . SM_PATH . 'images/blank.png'. $sQuote;
1960                     break;
1961             }
1962         } else {
1963             $aUrl = parse_url($attvalue);
1964             if (isset($aUrl['scheme'])) {
1965                 switch(strtolower($aUrl['scheme'])) {
1966                     case 'mailto':
1967                     case 'http':
1968                     case 'https':
1969                     case 'ftp':
1970                         if ($attname != 'href') {
1971                             if ($view_unsafe_images == false) {
1972                                 $attvalue = $sQuote . $secremoveimg . $sQuote;
1973                             } else {
1974                                 if (isset($aUrl['path'])) {
1975
1976                                     // No one has been able to show that image URIs
1977                                     // can be exploited, so for now, no restrictions
1978                                     // are made at all.  If this proves to be a problem,
1979                                     // the commented-out code below can be of help.
1980                                     // (One consideration is that I see nothing in this
1981                                     // function that specifically says that we will
1982                                     // only ever arrive here when inspecting an image
1983                                     // tag, although that does seem to be the end
1984                                     // result - e.g., <script src="..."> where malicious
1985                                     // image URIs are in fact a problem are already
1986                                     // filtered out elsewhere.
1987                                     /* ---------------------------------
1988                                     // validate image extension.
1989                                     $ext = strtolower(substr($aUrl['path'],strrpos($aUrl['path'],'.')));
1990                                     if (!in_array($ext,array('.jpeg','.jpg','xjpeg','.gif','.bmp','.jpe','.png','.xbm'))) {
1991                                         // If URI is to something other than
1992                                         // a regular image file, get the contents
1993                                         // and try to see if it is an image.
1994                                         // Don't use Fileinfo (finfo_file()) because
1995                                         // we'd need to make the admin configure the
1996                                         // location of the magic.mime file (FIXME: add finfo_file() support later?)
1997                                         //
1998                                         $mime_type = '';
1999                                         if (function_exists('mime_content_type')
2000                                          && ($FILE = @fopen($attvalue, 'rb', FALSE))) {
2001
2002                                             // fetch file
2003                                             //
2004                                             $file_contents = '';
2005                                             while (!feof($FILE)) {
2006                                                 $file_contents .= fread($FILE, 8192);
2007                                             }
2008                                             fclose($FILE);
2009
2010                                             // store file locally
2011                                             //
2012                                             global $attachment_dir, $username;
2013                                             $hashed_attachment_dir = getHashedDir($username, $attachment_dir);
2014                                             $localfilename = GenerateRandomString(32, '', 7);
2015                                             $full_localfilename = "$hashed_attachment_dir/$localfilename";
2016                                             while (file_exists($full_localfilename)) {
2017                                                 $localfilename = GenerateRandomString(32, '', 7);
2018                                                 $full_localfilename = "$hashed_attachment_dir/$localfilename";
2019                                             }
2020                                             $FILE = fopen("$hashed_attachment_dir/$localfilename", 'wb');
2021                                             fwrite($FILE, $file_contents);
2022                                             fclose($FILE);
2023
2024                                             // get mime type and remove file
2025                                             //
2026                                             $mime_type = mime_content_type("$hashed_attachment_dir/$localfilename");
2027                                             unlink("$hashed_attachment_dir/$localfilename");
2028                                         }
2029                                         // debug: echo "$attvalue FILE TYPE IS $mime_type<HR>";
2030                                         if (substr(strtolower($mime_type), 0, 5) != 'image') {
2031                                             $attvalue = $sQuote . SM_PATH . 'images/blank.png'. $sQuote;
2032                                         }
2033                                     }
2034                                     --------------------------------- */
2035                                 } else {
2036                                     $attvalue = $sQuote . SM_PATH . 'images/blank.png'. $sQuote;
2037                                 }
2038                             }
2039                         } else {
2040                             $attvalue = $sQuote . $attvalue . $sQuote;
2041                         }
2042                         break;
2043                     case 'outbind':
2044                         /**
2045                          * "Hack" fix for Outlook using propriatary outbind:// protocol in img tags.
2046                          * One day MS might actually make it match something useful, for now, falling
2047                          * back to using cid2http, so we can grab the blank.png.
2048                          */
2049                         $attvalue = $sQuote . sq_cid2http($message, $id, $attvalue, $mailbox) . $sQuote;
2050                         break;
2051                     case 'cid':
2052                         /**
2053                             * Turn cid: urls into http-friendly ones.
2054                             */
2055                         $attvalue = $sQuote . sq_cid2http($message, $id, $attvalue, $mailbox) . $sQuote;
2056                         break;
2057                     default:
2058                         $attvalue = $sQuote . SM_PATH . 'images/blank.png' . $sQuote;
2059                         break;
2060                 }
2061             } else {
2062                 if (!isset($aUrl['path']) || $aUrl['path'] != $secremoveimg) {
2063                     // parse_url did not lead to satisfying result
2064                     $attvalue = $sQuote . SM_PATH . 'images/blank.png' . $sQuote;
2065                 }
2066             }
2067         }
2068     }
2069 }
2070
2071 /**
2072  * This function edits the style definition to make them friendly and
2073  * usable in SquirrelMail.
2074  *
2075  * @param  $message  the message object
2076  * @param  $id       the message id
2077  * @param  $content  a string with whatever is between <style> and </style>
2078  * @param  $mailbox  the message mailbox
2079  * @return           a string with edited content.
2080  */
2081 function sq_fixstyle($body, $pos, $message, $id, $mailbox){
2082     $me = 'sq_fixstyle';
2083     // workaround for </style> in between comments
2084     $iCurrentPos = $pos;
2085     $content = '';
2086     $sToken = '';
2087     $bSucces = false;
2088     $bEndTag = false;
2089     for ($i=$pos,$iCount=strlen($body);$i<$iCount;++$i) {
2090         $char = $body[$i];
2091         switch ($char) {
2092             case '<':
2093                 $sToken = $char;
2094                 break;
2095             case '/':
2096                  if ($sToken == '<') {
2097                     $sToken .= $char;
2098                     $bEndTag = true;
2099                  } else {
2100                     $content .= $char;
2101                  }
2102                  break;
2103             case '>':
2104                  if ($bEndTag) {
2105                     $sToken .= $char;
2106                     if (preg_match('/\<\/\s*style\s*\>/i',$sToken,$aMatch)) {
2107                         $newpos = $i + 1;
2108                         $bSucces = true;
2109                         break 2;
2110                     } else {
2111                         $content .= $sToken;
2112                     }
2113                     $bEndTag = false;
2114                  } else {
2115                     $content .= $char;
2116                  }
2117                  break;
2118             case '!':
2119                 if ($sToken == '<') {
2120                     // possible comment
2121                     if (isset($body[$i+2]) && substr($body,$i,3) == '!--') {
2122                         $i = strpos($body,'-->',$i+3);
2123                         if ($i === false) { // no end comment
2124                             $i = strlen($body);
2125                         }
2126                         $sToken = '';
2127                     }
2128                 } else {
2129                     $content .= $char;
2130                 }
2131                 break;
2132             default:
2133                 if ($bEndTag) {
2134                     $sToken .= $char;
2135                 } else {
2136                     $content .= $char;
2137                 }
2138                 break;
2139         }
2140     }
2141     if ($bSucces == FALSE){
2142         return array(FALSE, strlen($body));
2143     }
2144
2145
2146
2147     /**
2148      * First look for general BODY style declaration, which would be
2149      * like so:
2150      * body {background: blah-blah}
2151      * and change it to .bodyclass so we can just assign it to a <div>
2152      */
2153     // $content = preg_replace("|body(\s*\{.*?\})|si", ".bodyclass\\1", $content);
2154     // Nah, this is even better - try to preface all CSS selectors with
2155     // our <div> class ID "bodyclass" then correct generic "body" selectors
2156     // TODO: this works pretty good but breaks stuff like this:
2157     //       @media print { body { font-size: 10pt; } }
2158     //       but there isn't an easy way to make this regex skip @media
2159     //       definitions... though lots of the ones in the wild will be
2160     //       correctly handled because they tend to end with a parenthesis, like:
2161     //       @media screen and (max-width:480px) { ...
2162     $content = preg_replace('/([a-z0-9._-][a-z0-9 >+~|:._-]*\s*(?:,|{.*?}))/si', '.bodyclass $1', $content);
2163     $content = str_replace('.bodyclass body', '.bodyclass', $content);
2164
2165     global $use_transparent_security_image;
2166     if ($use_transparent_security_image) $secremoveimg = '../images/spacer.png';
2167     else $secremoveimg = '../images/' . _("sec_remove_eng.png");
2168
2169     /**
2170     * Fix url('blah') declarations.
2171     */
2172     //   $content = preg_replace("|url\s*\(\s*([\'\"])\s*\S+script\s*:.*?([\'\"])\s*\)|si",
2173     //                           "url(\\1$secremoveimg\\2)", $content);
2174
2175     // first check for 8bit sequences and disallowed control characters
2176     if (preg_match('/[\16-\37\200-\377]+/',$content)) {
2177         $content = '<!-- style block removed by html filter due to presence of 8bit characters -->';
2178         return array($content, $newpos);
2179     }
2180
2181     // IE Sucks hard. We have a special function for it.
2182     sq_fixIE_idiocy($content);
2183
2184     // remove @import line
2185     $content = preg_replace("/^\s*(@import.*)$/mi","\n<!-- @import rules forbidden -->\n",$content);
2186
2187     // translate ur\l and variations (IE parses that)
2188     // TODO check if the sq_fixIE_idiocy function already handles this.
2189     $content = preg_replace("/(\\\\)?u(\\\\)?r(\\\\)?l(\\\\)?/i", 'url', $content);
2190     preg_match_all("/url\s*\((.+)\)/si",$content,$aMatch);
2191     if (count($aMatch)) {
2192         $aValue = $aReplace = array();
2193         foreach($aMatch[1] as $sMatch) {
2194             // url value
2195             $urlvalue = $sMatch;
2196             sq_fix_url('style',$urlvalue, $message, $id, $mailbox,"'");
2197             $aValue[] = $sMatch;
2198             $aReplace[] = $urlvalue;
2199         }
2200         $content = str_replace($aValue,$aReplace,$content);
2201     }
2202
2203     /**
2204      * Remove any backslashes, entities, and extraneous whitespace.
2205      */
2206     $contentTemp = $content;
2207     sq_defang($contentTemp);
2208     sq_unspace($contentTemp);
2209
2210     /**
2211      * Fix stupid css declarations which lead to vulnerabilities
2212      * in IE.
2213      *
2214      * Also remove "position" attribute, as it can easily be set
2215      * to "fixed" or "absolute" with "left" and "top" attributes
2216      * of zero, taking over the whole content frame.  It can also
2217      * be set to relative and move itself anywhere it wants to,
2218      * displaying content in areas it shouldn't be allowed to touch.
2219      */
2220     $match   = Array('/\/\*.*\*\//', // removes /* blah blah */
2221                     '/expression/i',
2222                     '/behaviou*r/i',
2223                     '/binding/i',
2224                     '/include-source/i',
2225                     '/javascript/i',
2226                     '/script/i',
2227                     '/position/i');
2228     $replace = Array('','idiocy', 'idiocy', 'idiocy', 'idiocy', 'idiocy', 'idiocy', '');
2229     $contentNew = preg_replace($match, $replace, $contentTemp);
2230     if ($contentNew !== $contentTemp) {
2231         // insecure css declarations are used. From now on we don't care
2232         // anymore if the css is destroyed by sq_deent, sq_unspace or sq_unbackslash
2233         $content = $contentNew;
2234     }
2235     return array($content, $newpos);
2236 }
2237
2238
2239 /**
2240  * This function converts cid: url's into the ones that can be viewed in
2241  * the browser.
2242  *
2243  * @param  $message  the message object
2244  * @param  $id       the message id
2245  * @param  $cidurl   the cid: url.
2246  * @param  $mailbox  the message mailbox
2247  * @return           a string with a http-friendly url
2248  */
2249 function sq_cid2http($message, $id, $cidurl, $mailbox){
2250     /**
2251      * Get rid of quotes.
2252      */
2253     $quotchar = substr($cidurl, 0, 1);
2254     if ($quotchar == '"' || $quotchar == "'"){
2255         $cidurl = str_replace($quotchar, "", $cidurl);
2256     } else {
2257         $quotchar = '';
2258     }
2259     $cidurl = substr(trim($cidurl), 4);
2260
2261     $match_str = '/\{.*?\}\//';
2262     $str_rep = '';
2263     $cidurl = preg_replace($match_str, $str_rep, $cidurl);
2264
2265     $linkurl = find_ent_id($cidurl, $message);
2266     /* in case of non-safe cid links $httpurl should be replaced by a sort of
2267        unsafe link image */
2268     $httpurl = '';
2269
2270     /**
2271      * This is part of a fix for Outlook Express 6.x generating
2272      * cid URLs without creating content-id headers. These images are
2273      * not part of the multipart/related html mail. The html contains
2274      * <img src="cid:{some_id}/image_filename.ext"> references to
2275      * attached images with as goal to render them inline although
2276      * the attachment disposition property is not inline.
2277      */
2278
2279     if (empty($linkurl)) {
2280         if (preg_match('/{.*}\//', $cidurl)) {
2281             $cidurl = preg_replace('/{.*}\//','', $cidurl);
2282             if (!empty($cidurl)) {
2283                 $linkurl = find_ent_id($cidurl, $message);
2284             }
2285         }
2286     }
2287
2288     if (!empty($linkurl)) {
2289         $httpurl = $quotchar . sqm_baseuri() . 'src/download.php?absolute_dl=true&amp;' .
2290             "passed_id=$id&amp;mailbox=" . urlencode($mailbox) .
2291             '&amp;ent_id=' . $linkurl . $quotchar;
2292     } else {
2293         /**
2294          * If we couldn't generate a proper img url, drop in a blank image
2295          * instead of sending back empty, otherwise it causes unusual behaviour
2296          */
2297         $httpurl = $quotchar . SM_PATH . 'images/blank.png' . $quotchar;
2298     }
2299
2300     return $httpurl;
2301 }
2302
2303 /**
2304  * This function changes the <body> tag into a <div> tag since we
2305  * can't really have a body-within-body.
2306  *
2307  * @param  $attary   an array of attributes and values of <body>
2308  * @param  $mailbox  mailbox we're currently reading (for cid2http)
2309  * @param  $message  current message (for cid2http)
2310  * @param  $id       current message id (for cid2http)
2311  * @return           a modified array of attributes to be set for <div>
2312  */
2313 function sq_body2div($attary, $mailbox, $message, $id){
2314     $me = 'sq_body2div';
2315     $divattary = Array('class' => "'bodyclass'");
2316     $text = '#000000';
2317     $has_bgc_stl = $has_txt_stl = false;
2318     $styledef = '';
2319     if (is_array($attary) && sizeof($attary) > 0){
2320         foreach ($attary as $attname=>$attvalue){
2321             $quotchar = substr($attvalue, 0, 1);
2322             $attvalue = str_replace($quotchar, "", $attvalue);
2323             switch ($attname){
2324                 case 'background':
2325                     $attvalue = sq_cid2http($message, $id, $attvalue, $mailbox);
2326                     $styledef .= "background-image: url('$attvalue'); ";
2327                     break;
2328                 case 'bgcolor':
2329                     $has_bgc_stl = true;
2330                     $styledef .= "background-color: $attvalue; ";
2331                     break;
2332                 case 'text':
2333                     $has_txt_stl = true;
2334                     $styledef .= "color: $attvalue; ";
2335                     break;
2336             }
2337         }
2338         // Outlook defines a white bgcolor and no text color. This can lead to
2339         // white text on a white bg with certain themes.
2340         if ($has_bgc_stl && !$has_txt_stl) {
2341             $styledef .= "color: $text; ";
2342         }
2343         if (strlen($styledef) > 0){
2344             $divattary["style"] = "\"$styledef\"";
2345         }
2346     }
2347     return $divattary;
2348 }
2349
2350 /**
2351  * This is the main function and the one you should actually be calling.
2352  * There are several variables you should be aware of an which need
2353  * special description.
2354  *
2355  * Since the description is quite lengthy, see it here:
2356  * http://linux.duke.edu/projects/mini/htmlfilter/
2357  *
2358  * @param $body                 the string with HTML you wish to filter
2359  * @param $tag_list             see description above
2360  * @param $rm_tags_with_content see description above
2361  * @param $self_closing_tags    see description above
2362  * @param $force_tag_closing    see description above
2363  * @param $rm_attnames          see description above
2364  * @param $bad_attvals          see description above
2365  * @param $add_attr_to_tag      see description above
2366  * @param $message              message object
2367  * @param $id                   message id
2368  * @param $recursively_called   boolean flag for recursive calls into this function (optional; default FALSE)
2369  * @return                      sanitized html safe to show on your pages.
2370  */
2371 function sq_sanitize($body,
2372                      $tag_list,
2373                      $rm_tags_with_content,
2374                      $self_closing_tags,
2375                      $force_tag_closing,
2376                      $rm_attnames,
2377                      $bad_attvals,
2378                      $add_attr_to_tag,
2379                      $message,
2380                      $id,
2381                      $mailbox,
2382                      $recursively_called=FALSE
2383                      ){
2384     $me = 'sq_sanitize';
2385
2386     /**
2387      * See if tag_list is of tags to remove or tags to allow.
2388      * false  means remove these tags
2389      * true   means allow these tags
2390      */
2391     $orig_tag_list = $tag_list;
2392     $rm_tags = array_shift($tag_list);
2393
2394     /**
2395      * Normalize rm_tags and rm_tags_with_content.
2396      */
2397     @array_walk($tag_list, 'sq_casenormalize');
2398     @array_walk($rm_tags_with_content, 'sq_casenormalize');
2399     @array_walk($self_closing_tags, 'sq_casenormalize');
2400
2401     $curpos = 0;
2402     $open_tags = Array();
2403     $trusted = "\n<!-- begin sanitized html -->\n";
2404     $skip_content = false;
2405     /**
2406      * Take care of netscape's stupid javascript entities like
2407      * &{alert('boo')};
2408      */
2409     $body = preg_replace("/&(\{.*?\};)/si", "&amp;\\1", $body);
2410
2411     while (($curtag = sq_getnxtag($body, $curpos)) != FALSE){
2412         list($tagname, $attary, $tagtype, $lt, $gt) = $curtag;
2413
2414         /**
2415          * RCDATA and RAWTEXT tags are handled differently:
2416          * next instance of closing tag is used, whether or not
2417          * the HTML is well formed before that
2418          */
2419         global $rcdata_rawtext_tags;
2420         if (!$recursively_called
2421          && in_array($tagname, $rcdata_rawtext_tags)
2422          && $tagtype === 1){
2423             $closing_tag = false;
2424             $closing_tag_offset = $curpos;
2425             // seek out the closing tag for the current RCDATA/RAWTEXT tag
2426             while (1) {
2427                 // first we need to move forward to next available closing tag
2428                 // (intentionally leave off the closing > and let sq_getnxtag() validate a proper tag syntax)
2429                 $next_tag = sq_findnxreg($body, $closing_tag_offset, "</\s*$tagname");
2430                 if ($next_tag === false) {
2431                     $closing_tag = false;
2432                     break;
2433                 }
2434                 // but then we have to make sure it's a well-formed tag
2435                 $closing_tag = sq_getnxtag($body, $next_tag[0]);
2436                 if ($closing_tag === false)
2437                     break;
2438                 else if ($closing_tag[0] !== false
2439                  // these should be redundant
2440                  && $closing_tag[0] === $tagname && $closing_tag[2] === 2) {
2441                     $trusted .= sq_sanitize(substr($body, $curpos, $closing_tag[4] - $curpos + 1),
2442                                             $orig_tag_list, $rm_tags_with_content, $self_closing_tags,
2443                                             $force_tag_closing, $rm_attnames, $bad_attvals, $add_attr_to_tag,
2444                                             $message, $id, $mailbox, true);
2445                     $curpos = $closing_tag[4] + 1;
2446                     continue 2;
2447                 }
2448                 $closing_tag_offset = $next_tag[0] + 1;
2449             }
2450             if ($closing_tag === false)
2451             { /* no-op... there was no closing tag for this RCDATA/RAWTEXT tag - we could probably set $curpos to the end of $body, but this HTML is malformed anyway and should just fall apart on its own */ }
2452         }
2453
2454         $free_content = substr($body, $curpos, $lt-$curpos);
2455         /**
2456          * Take care of <style>
2457          */
2458         if ($tagname == "style" && $tagtype == 1){
2459             list($free_content, $curpos) =
2460                 sq_fixstyle($body, $gt+1, $message, $id, $mailbox);
2461             if ($free_content != FALSE){
2462                 if ( !empty($attary) ) {
2463                     $attary = sq_fixatts($tagname,
2464                                          $attary,
2465                                          $rm_attnames,
2466                                          $bad_attvals,
2467                                          $add_attr_to_tag,
2468                                          $message,
2469                                          $id,
2470                                          $mailbox
2471                                          );
2472                 }
2473                 $trusted .= sq_tagprint($tagname, $attary, $tagtype);
2474                 $trusted .= $free_content;
2475                 $trusted .= sq_tagprint($tagname, false, 2);
2476             }
2477             continue;
2478         }
2479         if ($skip_content == false){
2480             $trusted .= $free_content;
2481         }
2482         if ($tagname != FALSE){
2483             if ($tagtype == 2){
2484                 if ($skip_content == $tagname){
2485                     /**
2486                      * Got to the end of tag we needed to remove.
2487                      */
2488                     $tagname = false;
2489                     $skip_content = false;
2490                 } else {
2491                     if ($skip_content == false){
2492                         if ($tagname == "body"){
2493                             $tagname = "div";
2494                         }
2495                         if (isset($open_tags[$tagname]) &&
2496                                 $open_tags[$tagname] > 0){
2497                             $open_tags[$tagname]--;
2498                         } else {
2499                             $tagname = false;
2500                         }
2501                     }
2502                 }
2503             } else {
2504                 /**
2505                  * $rm_tags_with_content
2506                  */
2507                 if ($skip_content == false){
2508                     /**
2509                      * See if this is a self-closing type and change
2510                      * tagtype appropriately.
2511                      */
2512                     if ($tagtype == 1
2513                             && in_array($tagname, $self_closing_tags)){
2514                         $tagtype = 3;
2515                     }
2516                     /**
2517                      * See if we should skip this tag and any content
2518                      * inside it.
2519                      */
2520                     if ($tagtype == 1 &&
2521                             in_array($tagname, $rm_tags_with_content)){
2522                         $skip_content = $tagname;
2523                     } else {
2524                         if (($rm_tags == false
2525                                     && in_array($tagname, $tag_list)) ||
2526                                 ($rm_tags == true &&
2527                                  !in_array($tagname, $tag_list))){
2528                             $tagname = false;
2529                         } else {
2530                             /**
2531                              * Convert body into div.
2532                              */
2533                             if ($tagname == "body"){
2534                                 $tagname = "div";
2535                                 $attary = sq_body2div($attary, $mailbox,
2536                                         $message, $id);
2537                             }
2538                             if ($tagtype == 1){
2539                                 if (isset($open_tags[$tagname])){
2540                                     $open_tags[$tagname]++;
2541                                 } else {
2542                                     $open_tags[$tagname]=1;
2543                                 }
2544                             }
2545                             /**
2546                              * This is where we run other checks.
2547                              */
2548                             if (is_array($attary) && sizeof($attary) > 0){
2549                                 $attary = sq_fixatts($tagname,
2550                                                      $attary,
2551                                                      $rm_attnames,
2552                                                      $bad_attvals,
2553                                                      $add_attr_to_tag,
2554                                                      $message,
2555                                                      $id,
2556                                                      $mailbox
2557                                                      );
2558                             }
2559                         }
2560                     }
2561                 }
2562             }
2563             if ($tagname != false && $skip_content == false){
2564                 $trusted .= sq_tagprint($tagname, $attary, $tagtype);
2565             }
2566         }
2567         $curpos = $gt+1;
2568     }
2569     $trusted .= substr($body, $curpos, strlen($body)-$curpos);
2570     if ($force_tag_closing == true){
2571         foreach ($open_tags as $tagname=>$opentimes){
2572             while ($opentimes > 0){
2573                 $trusted .= '</' . $tagname . '>';
2574                 $opentimes--;
2575             }
2576         }
2577         $trusted .= "\n";
2578     }
2579     $trusted .= "<!-- end sanitized html -->\n";
2580     return $trusted;
2581 }
2582
2583 /**
2584  * This is a wrapper function to call html sanitizing routines.
2585  *
2586  * @param  $body  the body of the message
2587  * @param  $id    the id of the message
2588
2589  * @param  $message
2590  * @param  $mailbox
2591  * @param  boolean $take_mailto_links When TRUE, converts mailto: links
2592  *                                    into internal SM compose links
2593  *                                    (optional; default = TRUE)
2594  * @return        a string with html safe to display in the browser.
2595  */
2596 function magicHTML($body, $id, $message, $mailbox = 'INBOX', $take_mailto_links =true) {
2597
2598     // require_once(SM_PATH . 'functions/url_parser.php');  // for $MailTo_PReg_Match
2599
2600     global $attachment_common_show_images, $view_unsafe_images,
2601            $has_unsafe_images, $allow_svg_display, $rcdata_rawtext_tags,
2602            $remove_rcdata_rawtext_tags_and_content;
2603
2604     $rcdata_rawtext_tags = array(
2605         "noscript",
2606         "noframes",
2607         "noembed",
2608         "textarea",
2609         // also "title", "xmp", "script", "iframe", "plaintext" which we already remove below
2610     );
2611
2612     /**
2613      * Don't display attached images in HTML mode.
2614      *
2615      * SB: why?
2616      */
2617     $attachment_common_show_images = false;
2618     $tag_list = Array(
2619             false, // remove these tags
2620             "meta",
2621             "html",
2622             "head",
2623             "base",
2624             "link",
2625             "frame",
2626             "iframe",
2627             "plaintext",
2628             "marquee",
2629             );
2630
2631     $rm_tags_with_content = Array(
2632             "script",
2633             "object",
2634             "applet",
2635             "embed",
2636             "title",
2637             "frameset",
2638             "xmp",
2639             "xml",
2640             );
2641     if (!$allow_svg_display)
2642         $rm_tags_with_content[] = 'svg';
2643     /**
2644      * SquirrelMail will parse RCDATA and RAWTEXT tags and handle them as the special
2645      * case that they are, but if you prefer to remove them and their contents entirely
2646      * (in most cases, should be a safe thing with minimal impact), you can add the
2647      * following to config/config_local.php
2648      *    $remove_rcdata_rawtext_tags_and_content = TRUE;
2649      */
2650     if ($remove_rcdata_rawtext_tags_and_content)
2651         $rm_tags_with_content = array_merge($rm_tags_with_content, $rcdata_rawtext_tags);
2652
2653     $self_closing_tags =  Array(
2654             "img",
2655             "br",
2656             "hr",
2657             "input",
2658             "outbind",
2659             );
2660
2661     $force_tag_closing = true;
2662
2663     $rm_attnames = Array(
2664             "/.*/" =>
2665             Array(
2666                 "/target/i",
2667                 "/^on.*/i",
2668                 "/^dynsrc/i",
2669                 "/^data.*/i",
2670                 "/^lowsrc.*/i",
2671                 )
2672             );
2673
2674     global $use_transparent_security_image;
2675     if ($use_transparent_security_image) $secremoveimg = '../images/spacer.png';
2676     else $secremoveimg = '../images/' . _("sec_remove_eng.png");
2677
2678     $bad_attvals = Array(
2679             "/.*/" =>
2680             Array(
2681                 "/^src|background/i" =>
2682                 Array(
2683                     Array(
2684                         "/^([\'\"])\s*\S+script\s*:.*([\'\"])/si",
2685                         "/^([\'\"])\s*mocha\s*:*.*([\'\"])/si",
2686                         "/^([\'\"])\s*about\s*:.*([\'\"])/si"
2687                         ),
2688                     Array(
2689                         "\\1$secremoveimg\\2",
2690                         "\\1$secremoveimg\\2",
2691                         "\\1$secremoveimg\\2",
2692                         )
2693                     ),
2694                 "/^href|action/i" =>
2695                 Array(
2696                     Array(
2697                         "/^([\'\"])\s*\S+script\s*:.*([\'\"])/si",
2698                         "/^([\'\"])\s*mocha\s*:*.*([\'\"])/si",
2699                         "/^([\'\"])\s*about\s*:.*([\'\"])/si"
2700                         ),
2701                     Array(
2702                         "\\1#\\1",
2703                         "\\1#\\1",
2704                         "\\1#\\1"
2705                         )
2706                     ),
2707         "/^style/i" =>
2708             Array(
2709                 Array(
2710                     "/\/\*.*\*\//",
2711                     "/expression/i",
2712                     "/binding/i",
2713                     "/behaviou*r/i",
2714                     "/include-source/i",
2715
2716                     // position:relative can also be exploited
2717                     // to put content outside of email body area
2718                     // and position:fixed is similarly exploitable
2719                     // as position:absolute, so we'll remove it
2720                     // altogether....
2721                     //
2722                     // Does this screw up legitimate HTML messages?
2723                     // If so, the only fix I see is to allow position
2724                     // attributes (any values?  I think we still have
2725                     // to block static and fixed) only if $use_iframe
2726                     // is enabled (1.5.0+)
2727                     //
2728                     // was:   "/position\s*:\s*absolute/i",
2729                     //
2730                     "/position\s*:/i",
2731
2732                     "/(\\\\)?u(\\\\)?r(\\\\)?l(\\\\)?/i",
2733                     "/url\s*\(\s*([\'\"])\s*\S+script\s*:.*([\'\"])\s*\)/si",
2734                     "/url\s*\(\s*([\'\"])\s*mocha\s*:.*([\'\"])\s*\)/si",
2735                     "/url\s*\(\s*([\'\"])\s*about\s*:.*([\'\"])\s*\)/si",
2736                     "/(.*)\s*:\s*url\s*\(\s*([\'\"]*)\s*\S+script\s*:.*([\'\"]*)\s*\)/si",
2737                     ),
2738                 Array(
2739                     "",
2740                     "idiocy",
2741                     "idiocy",
2742                     "idiocy",
2743                     "idiocy",
2744                     "idiocy",
2745                     "url",
2746                     "url(\\1#\\1)",
2747                     "url(\\1#\\1)",
2748                     "url(\\1#\\1)",
2749                     "\\1:url(\\2#\\3)"
2750                     )
2751                 )
2752             )
2753         );
2754
2755     // If there's no "view_unsafe_images" variable in the URL, turn unsafe
2756     // images off by default.
2757     sqgetGlobalVar('view_unsafe_images', $view_unsafe_images, SQ_GET, FALSE);
2758
2759     if (!$view_unsafe_images){
2760         /**
2761          * Remove any references to http/https if view_unsafe_images set
2762          * to false.
2763          */
2764         array_push($bad_attvals['/.*/']['/^src|background/i'][0],
2765                 '/^([\'\"])\s*https*:.*([\'\"])/si');
2766         array_push($bad_attvals['/.*/']['/^src|background/i'][1],
2767                 "\\1$secremoveimg\\1");
2768         array_push($bad_attvals['/.*/']['/^style/i'][0],
2769                 '/url\([\'\"]?https?:[^\)]*[\'\"]?\)/si');
2770         array_push($bad_attvals['/.*/']['/^style/i'][1],
2771                 "url(\\1$secremoveimg\\1)");
2772     }
2773
2774     $add_attr_to_tag = Array(
2775             "/^a$/i" =>
2776             Array('target'=>'"_blank"',
2777                 'title'=>'"'._("This external link will open in a new window").'"'
2778                 )
2779             );
2780     $trusted = sq_sanitize($body,
2781                            $tag_list,
2782                            $rm_tags_with_content,
2783                            $self_closing_tags,
2784                            $force_tag_closing,
2785                            $rm_attnames,
2786                            $bad_attvals,
2787                            $add_attr_to_tag,
2788                            $message,
2789                            $id,
2790                            $mailbox
2791                            );
2792     if (strpos($trusted,$secremoveimg)){
2793         $has_unsafe_images = true;
2794     }
2795
2796     // we want to parse mailto's in HTML output, change to SM compose links
2797     // this is a modified version of code from url_parser.php... but Marc is
2798     // right: we need a better filtering implementation; adding this randomly
2799     // here is not a great solution
2800     //
2801     if ($take_mailto_links) {
2802         // parseUrl($trusted);   // this even parses URLs inside of tags... too aggressive
2803         global $MailTo_PReg_Match;
2804         // some mailers (Microsoft, surprise surprise) produce mailto strings without being
2805         // inside an anchor (link) tag, so we have to make sure the regex looks for the
2806         // quote before mailto, and we'll also try to convert the non-links back into links
2807         $MailTo_PReg_Match = '/([\'"])?mailto:' . substr($MailTo_PReg_Match, 1) ;
2808         if ((preg_match_all($MailTo_PReg_Match, $trusted, $regs)) && ($regs[0][0] != '')) {
2809             foreach ($regs[0] as $i => $mailto_before) {
2810                 $mailto_params = $regs[11][$i];
2811
2812                 // get rid of any leading quote we may have captured but don't care about
2813                 //
2814                 $mailto_before = ltrim($mailto_before, '"\'');
2815
2816                 // get rid of any tailing quote since we have to add send_to to the end
2817                 //
2818                 $mailto_before = rtrim($mailto_before, '"\'');
2819                 $mailto_params = rtrim($mailto_params, '"\'');
2820
2821                 if ($regs[2][$i]) {    //if there is an email addr before '?', we need to merge it with the params
2822                     $to = 'to=' . $regs[2][$i];
2823                     if (strpos($mailto_params, 'to=') > -1)    //already a 'to='
2824                         $mailto_params = str_replace('to=', $to . '%2C%20', $mailto_params);
2825                     else {
2826                         if ($mailto_params)    //already some params, append to them
2827                             $mailto_params .= '&amp;' . $to;
2828                         else
2829                             $mailto_params .= '?' . $to;
2830                     }
2831                 }
2832
2833                 $url_str = preg_replace(array('/to=/i', '/(?<!b)cc=/i', '/bcc=/i'), array('send_to=', 'send_to_cc=', 'send_to_bcc='), $mailto_params);
2834
2835                 // we'll already have target=_blank, no need to allow comp_in_new
2836                 // here (which would be a lot more work anyway)
2837                 //
2838                 global $compose_new_win;
2839                 $temp_comp_in_new = $compose_new_win;
2840                 $compose_new_win = 0;
2841                 $comp_uri = makeComposeLink('src/compose.php' . $url_str, $mailto_before);
2842                 $compose_new_win = $temp_comp_in_new;
2843
2844                 // remove <a href=" and anything after the next quote (we only
2845                 // need the uri, not the link HTML) in compose uri
2846                 //
2847                 // but only do this if the original mailto was in a real anchor tag
2848                 //
2849                 if (!empty($regs[1][$i])) {
2850                     $comp_uri = substr($comp_uri, 9);
2851                     $comp_uri = substr($comp_uri, 0, strpos($comp_uri, '"', 1));
2852                 }
2853                 $trusted = str_replace($mailto_before, $comp_uri, $trusted);
2854             }
2855         }
2856     }
2857
2858     return $trusted;
2859 }
2860
2861 /**
2862  * function SendDownloadHeaders - send file to the browser
2863  *
2864  * Original Source: SM core src/download.php
2865  * moved here to make it available to other code, and separate
2866  * front end from back end functionality.
2867  *
2868  * @param string $type0 first half of mime type
2869  * @param string $type1 second half of mime type
2870  * @param string $filename filename to tell the browser for downloaded file
2871  * @param boolean $force whether to force the download dialog to pop
2872  * @param optional integer $filesize send the Content-Header and length to the browser
2873  * @return void
2874  */
2875 function SendDownloadHeaders($type0, $type1, $filename, $force, $filesize=0) {
2876     global $languages, $squirrelmail_language;
2877     $isIE = $isIE6plus = false;
2878
2879     sqgetGlobalVar('HTTP_USER_AGENT', $HTTP_USER_AGENT, SQ_SERVER);
2880
2881     if (strstr($HTTP_USER_AGENT, 'compatible; MSIE ') !== false &&
2882             strstr($HTTP_USER_AGENT, 'Opera') === false) {
2883         $isIE = true;
2884     }
2885
2886     if (preg_match('/compatible; MSIE ([0-9]+)/', $HTTP_USER_AGENT, $match) &&
2887         ((int)$match[1]) >= 6 && strstr($HTTP_USER_AGENT, 'Opera') === false) {
2888         $isIE6plus = true;
2889     }
2890
2891     if (isset($languages[$squirrelmail_language]['XTRA_CODE']) &&
2892             function_exists($languages[$squirrelmail_language]['XTRA_CODE'] . '_downloadfilename')) {
2893         $filename =
2894             call_user_func($languages[$squirrelmail_language]['XTRA_CODE'] . '_downloadfilename', $filename, $HTTP_USER_AGENT);
2895     } else {
2896         $filename = preg_replace('/[\\\\\/:*?"<>|;]/', '_', str_replace('&nbsp;', ' ', $filename));
2897     }
2898
2899     // A Pox on Microsoft and it's Internet Explorer!
2900     //
2901     // IE has lots of bugs with file downloads.
2902     // It also has problems with SSL.  Both of these cause problems
2903     // for us in this function.
2904     //
2905     // See this article on Cache Control headers and SSL
2906     // http://support.microsoft.com/default.aspx?scid=kb;en-us;323308
2907     //
2908     // The best thing you can do for IE is to upgrade to the latest
2909     // version
2910     //set all the Cache Control Headers for IE
2911     if ($isIE) {
2912         $filename=rawurlencode($filename);
2913         header ("Pragma: public");
2914         header ("Cache-Control: no-store, max-age=0, no-cache, must-revalidate"); // HTTP/1.1
2915         // does nothing - see: https://blogs.msdn.microsoft.com/ieinternals/2009/07/20/internet-explorers-cache-control-extensions/
2916         // header ("Cache-Control: post-check=0, pre-check=0", false);
2917         header ("Cache-Control: private");
2918
2919         //set the inline header for IE, we'll add the attachment header later if we need it
2920         header ("Content-Disposition: inline; filename=$filename");
2921     }
2922
2923     if (!$force) {
2924         // Try to show in browser window
2925         header ("Content-Disposition: inline; filename=\"$filename\"");
2926         header ("Content-Type: $type0/$type1; name=\"$filename\"");
2927     } else {
2928         // Try to pop up the "save as" box
2929
2930         // IE makes this hard.  It pops up 2 save boxes, or none.
2931         // http://support.microsoft.com/support/kb/articles/Q238/5/88.ASP
2932         // http://support.microsoft.com/default.aspx?scid=kb;EN-US;260519
2933         // But, according to Microsoft, it is "RFC compliant but doesn't
2934         // take into account some deviations that allowed within the
2935         // specification."  Doesn't that mean RFC non-compliant?
2936         // http://support.microsoft.com/support/kb/articles/Q258/4/52.ASP
2937
2938         // all browsers need the application/octet-stream header for this
2939         header ("Content-Type: application/octet-stream; name=\"$filename\"");
2940
2941         // http://support.microsoft.com/support/kb/articles/Q182/3/15.asp
2942         // Do not have quotes around filename, but that applied to
2943         // "attachment"... does it apply to inline too?
2944         header ("Content-Disposition: attachment; filename=\"$filename\"");
2945
2946         if ($isIE && !$isIE6plus) {
2947             // This combination seems to work mostly.  IE 5.5 SP 1 has
2948             // known issues (see the Microsoft Knowledge Base)
2949
2950             // This works for most types, but doesn't work with Word files
2951             header ("Content-Type: application/download; name=\"$filename\"");
2952             header ("Content-Type: application/force-download; name=\"$filename\"");
2953             // These are spares, just in case.  :-)
2954             //header("Content-Type: $type0/$type1; name=\"$filename\"");
2955             //header("Content-Type: application/x-msdownload; name=\"$filename\"");
2956             //header("Content-Type: application/octet-stream; name=\"$filename\"");
2957         } else if ($isIE) {
2958              // This is to prevent IE for MIME sniffing and auto open a file in IE
2959              header ("Content-Type: application/force-download; name=\"$filename\"");
2960         } else {
2961             // another application/octet-stream forces download for Netscape
2962             header ("Content-Type: application/octet-stream; name=\"$filename\"");
2963         }
2964     }
2965
2966     //send the content-length header if the calling function provides it
2967     if ($filesize > 0) {
2968         header("Content-Length: $filesize");
2969     }
2970
2971 }  // end fn SendDownloadHeaders