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