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