ree Software Foundation; either version 2 of the License, * or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA * http://www.gnu.org/licenses/gpl.html * * [kses strips evil scripts!] * * Added wp_ prefix to avoid conflicts with existing kses users * * @version 0.2.2 * @copyright (C) 2002, 2003, 2005 * @author Ulf Harnhammar * * @package External * @subpackage KSES * */ /** * You can override this in a plugin. * * The wp_kses_allowed_html filter is more powerful and supplies context. * CUSTOM_TAGS is not recommended and should be considered deprecated. * * @see wp_kses_allowed_html() * * @since 1.2.0 */ if ( ! defined( 'CUSTOM_TAGS' ) ) define( 'CUSTOM_TAGS', false ); if ( ! CUSTOM_TAGS ) { /** * Kses global for default allowable HTML tags. * * Can be override by using CUSTOM_TAGS constant. * * @global array $allowedposttags * @since 2.0.0 */ $allowedposttags = array( 'address' => array(), 'a' => array( 'href' => true, 'rel' => true, 'rev' => true, 'name' => true, 'target' => true, ), 'abbr' => array(), 'acronym' => array(), 'area' => array( 'alt' => true, 'coords' => true, 'href' => true, 'nohref' => true, 'shape' => true, 'target' => true, ), 'article' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'aside' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'b' => array(), 'big' => array(), 'blockquote' => array( 'cite' => true, 'lang' => true, 'xml:lang' => true, ), 'br' => array(), 'button' => array( 'disabled' => true, 'name' => true, 'type' => true, 'value' => true, ), 'caption' => array( 'align' => true, ), 'cite' => array( 'dir' => true, 'lang' => true, ), 'code' => array(), 'col' => array( 'align' => true, 'char' => true, 'charoff' => true, 'span' => true, 'dir' => true, 'valign' => true, 'width' => true, ), 'del' => array( 'datetime' => true, ), 'dd' => array(), 'dfn' => array(), 'details' => array( 'align' => true, 'dir' => true, 'lang' => true, 'open' => true, 'xml:lang' => true, ), 'div' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'dl' => array(), 'dt' => array(), 'em' => array(), 'fieldset' => array(), 'figure' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'figcaption' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'font' => array( 'color' => true, 'face' => true, 'size' => true, ), 'footer' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'form' => array( 'action' => true, 'accept' => true, 'accept-charset' => true, 'enctype' => true, 'method' => true, 'name' => true, 'target' => true, ), 'h1' => array( 'align' => true, ), 'h2' => array( 'align' => true, ), 'h3' => array( 'align' => true, ), 'h4' => array( 'align' => true, ), 'h5' => array( 'align' => true, ), 'h6' => array( 'align' => true, ), 'header' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'hgroup' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'hr' => array( 'align' => true, 'noshade' => true, 'size' => true, 'width' => true, ), 'i' => array(), 'img' => array( 'alt' => true, 'align' => true, 'border' => true, 'height' => true, 'hspace' => true, 'longdesc' => true, 'vspace' => true, 'src' => true, 'usemap' => true, 'width' => true, ), 'ins' => array( 'datetime' => true, 'cite' => true, ), 'kbd' => array(), 'label' => array( 'for' => true, ), 'legend' => array( 'align' => true, ), 'li' => array( 'align' => true, 'value' => true, ), 'map' => array( 'name' => true, ), 'mark' => array(), 'menu' => array( 'type' => true, ), 'nav' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'p' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'pre' => array( 'width' => true, ), 'q' => array( 'cite' => true, ), 's' => array(), 'samp' => array(), 'span' => array( 'dir' => true, 'align' => true, 'lang' => true, 'xml:lang' => true, ), 'section' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'small' => array(), 'strike' => array(), 'strong' => array(), 'sub' => array(), 'summary' => array( 'align' => true, 'dir' => true, 'lang' => true, 'xml:lang' => true, ), 'sup' => array(), 'table' => array( 'align' => true, 'bgcolor' => true, 'border' => true, 'cellpadding' => true, 'cellspacing' => true, 'dir' => true, 'rules' => true, 'summary' => true, 'width' => true, ), 'tbody' => array( 'align' => true, 'char' => true, 'charoff' => true, 'valign' => true, ), 'td' => array( 'abbr' => true, 'align' => true, 'axis' => true, 'bgcolor' => true, 'char' => true, 'charoff' => true, 'colspan' => true, 'dir' => true, 'headers' => true, 'height' => true, 'nowrap' => true, 'rowspan' => true, 'scope' => true, 'valign' => true, 'width' => true, ), 'textarea' => array( 'cols' => true, 'rows' => true, 'disabled' => true, 'name' => true, 'readonly' => true, ), 'tfoot' => array( 'align' => true, 'char' => true, 'charoff' => true, 'valign' => true, ), 'th' => array( 'abbr' => true, 'align' => true, 'axis' => true, 'bgcolor' => true, 'char' => true, 'charoff' => true, 'colspan' => true, 'headers' => true, 'height' => true, 'nowrap' => true, 'rowspan' => true, 'scope' => true, 'valign' => true, 'width' => true, ), 'thead' => array( 'align' => true, 'char' => true, 'charoff' => true, 'valign' => true, ), 'title' => array(), 'tr' => array( 'align' => true, 'bgcolor' => true, 'char' => true, 'charoff' => true, 'valign' => true, ), 'tt' => array(), 'u' => array(), 'ul' => array( 'type' => true, ), 'ol' => array( 'start' => true, 'type' => true, ), 'var' => array(), ); /** * Kses allowed HTML elements. * * @global array $allowedtags * @since 1.0.0 */ $allowedtags = array( 'a' => array( 'href' => true, 'title' => true, ), 'abbr' => array( 'title' => true, ), 'acronym' => array( 'title' => true, ), 'b' => array(), 'blockquote' => array( 'cite' => true, ), 'cite' => array(), 'code' => array(), 'del' => array( 'datetime' => true, ), 'em' => array(), 'i' => array(), 'q' => array( 'cite' => true, ), 'strike' => array(), 'strong' => array(), ); $allowedentitynames = array( 'nbsp', 'iexcl', 'cent', 'pound', 'curren', 'yen', 'brvbar', 'sect', 'uml', 'copy', 'ordf', 'laquo', 'not', 'shy', 'reg', 'macr', 'deg', 'plusmn', 'acute', 'micro', 'para', 'middot', 'cedil', 'ordm', 'raquo', 'iquest', 'Agrave', 'Aacute', 'Acirc', 'Atilde', 'Auml', 'Aring', 'AElig', 'Ccedil', 'Egrave', 'Eacute', 'Ecirc', 'Euml', 'Igrave', 'Iacute', 'Icirc', 'Iuml', 'ETH', 'Ntilde', 'Ograve', 'Oacute', 'Ocirc', 'Otilde', 'Ouml', 'times', 'Oslash', 'Ugrave', 'Uacute', 'Ucirc', 'Uuml', 'Yacute', 'THORN', 'szlig', 'agrave', 'aacute', 'acirc', 'atilde', 'auml', 'aring', 'aelig', 'ccedil', 'egrave', 'eacute', 'ecirc', 'euml', 'igrave', 'iacute', 'icirc', 'iuml', 'eth', 'ntilde', 'ograve', 'oacute', 'ocirc', 'otilde', 'ouml', 'divide', 'oslash', 'ugrave', 'uacute', 'ucirc', 'uuml', 'yacute', 'thorn', 'yuml', 'quot', 'amp', 'lt', 'gt', 'apos', 'OElig', 'oelig', 'Scaron', 'scaron', 'Yuml', 'circ', 'tilde', 'ensp', 'emsp', 'thinsp', 'zwnj', 'zwj', 'lrm', 'rlm', 'ndash', 'mdash', 'lsquo', 'rsquo', 'sbquo', 'ldquo', 'rdquo', 'bdquo', 'dagger', 'Dagger', 'permil', 'lsaquo', 'rsaquo', 'euro', 'fnof', 'Alpha', 'Beta', 'Gamma', 'Delta', 'Epsilon', 'Zeta', 'Eta', 'Theta', 'Iota', 'Kappa', 'Lambda', 'Mu', 'Nu', 'Xi', 'Omicron', 'Pi', 'Rho', 'Sigma', 'Tau', 'Upsilon', 'Phi', 'Chi', 'Psi', 'Omega', 'alpha', 'beta', 'gamma', 'delta', 'epsilon', 'zeta', 'eta', 'theta', 'iota', 'kappa', 'lambda', 'mu', 'nu', 'xi', 'omicron', 'pi', 'rho', 'sigmaf', 'sigma', 'tau', 'upsilon', 'phi', 'chi', 'psi', 'omega', 'thetasym', 'upsih', 'piv', 'bull', 'hellip', 'prime', 'Prime', 'oline', 'frasl', 'weierp', 'image', 'real', 'trade', 'alefsym', 'larr', 'uarr', 'rarr', 'darr', 'harr', 'crarr', 'lArr', 'uArr', 'rArr', 'dArr', 'hArr', 'forall', 'part', 'exist', 'empty', 'nabla', 'isin', 'notin', 'ni', 'prod', 'sum', 'minus', 'lowast', 'radic', 'prop', 'infin', 'ang', 'and', 'or', 'cap', 'cup', 'int', 'sim', 'cong', 'asymp', 'ne', 'equiv', 'le', 'ge', 'sub', 'sup', 'nsub', 'sube', 'supe', 'oplus', 'otimes', 'perp', 'sdot', 'lceil', 'rceil', 'lfloor', 'rfloor', 'lang', 'rang', 'loz', 'spades', 'clubs', 'hearts', 'diams', 'sup1', 'sup2', 'sup3', 'frac14', 'frac12', 'frac34', 'there4', ); $allowedposttags = array_map( '_wp_add_global_attributes', $allowedposttags ); } else { $allowedtags = wp_kses_array_lc( $allowedtags ); $allowedposttags = wp_kses_array_lc( $allowedposttags ); } /** * Filters content and keeps only allowable HTML elements. * * This function makes sure that only the allowed HTML element names, attribute * names and attribute values plus only sane HTML entities will occur in * $string. You have to remove any slashes from PHP's magic quotes before you * call this function. * * The default allowed protocols are 'http', 'https', 'ftp', 'mailto', 'news', * 'irc', 'gopher', 'nntp', 'feed', 'telnet, 'mms', 'rtsp' and 'svn'. This * covers all common link protocols, except for 'javascript' which should not * be allowed for untrusted users. * * @since 1.0.0 * * @param string $string Content to filter through kses * @param array $allowed_html List of allowed HTML elements * @param array $allowed_protocols Optional. Allowed protocol in links. * @return string Filtered content with only allowed HTML elements */ function wp_kses( $string, $allowed_html, $allowed_protocols = array() ) { if ( empty( $allowed_protocols ) ) $allowed_protocols = wp_allowed_protocols(); $string = wp_kses_no_null($string); $string = wp_kses_js_entities($string); $string = wp_kses_normalize_entities($string); $string = wp_kses_hook($string, $allowed_html, $allowed_protocols); // WP changed the order of these funcs and added args to wp_kses_hook return wp_kses_split($string, $allowed_html, $allowed_protocols); } /** * Return a list of allowed tags and attributes for a given context. * * @since 3.5.0 * * @param string $context The context for which to retrieve tags. Allowed values are * post | strip | data | entities or the name of a field filter such as pre_user_description. * @return array List of allowed tags and their allowed attributes. */ function wp_kses_allowed_html( $context = '' ) { global $allowedposttags, $allowedtags, $allowedentitynames; if ( is_array( $context ) ) { /** * Filter HTML elements allowed for a given context. * * @since 3.5.0 * * @param string $tags Allowed tags, attributes, and/or entities. * @param string $context Context to judge allowed tags by. Allowed values are 'post', * 'data', 'strip', 'entities', 'explicit', or the name of a filter. */ return apply_filters( 'wp_kses_allowed_html', $context, 'explicit' ); } switch ( $context ) { case 'post': /** This filter is documented in wp-includes/kses.php */ return apply_filters( 'wp_kses_allowed_html', $allowedposttags, $context ); break; case 'user_description': case 'pre_user_description': $tags = $allowedtags; $tags['a']['rel'] = true; /** This filter is documented in wp-includes/kses.php */ return apply_filters( 'wp_kses_allowed_html', $tags, $context ); break; case 'strip': /** This filter is documented in wp-includes/kses.php */ return apply_filters( 'wp_kses_allowed_html', array(), $context ); break; case 'entities': /** This filter is documented in wp-includes/kses.php */ return apply_filters( 'wp_kses_allowed_html', $allowedentitynames, $context); break; case 'data': default: /** This filter is documented in wp-includes/kses.php */ return apply_filters( 'wp_kses_allowed_html', $allowedtags, $context ); } } /** * You add any kses hooks here. * * There is currently only one kses WordPress hook and it is called here. All * parameters are passed to the hooks and expected to receive a string. * * @since 1.0.0 * * @param string $string Content to filter through kses * @param array $allowed_html List of allowed HTML elements * @param array $allowed_protocols Allowed protocol in links * @return string Filtered content through 'pre_kses' hook */ function wp_kses_hook( $string, $allowed_html, $allowed_protocols ) { /** * Filter content to be run through kses. * * @since 2.3.0 * * @param string $string Content to run through kses. * @param array $allowed_html Allowed HTML elements. * @param array $allowed_protocols Allowed protocol in links. */ $string = apply_filters( 'pre_kses', $string, $allowed_html, $allowed_protocols ); return $string; } /** * This function returns kses' version number. * * @since 1.0.0 * * @return string KSES Version Number */ function wp_kses_version() { return '0.2.2'; } /** * Searches for HTML tags, no matter how malformed. * * It also matches stray ">" characters. * * @since 1.0.0 * * @param string $string Content to filter * @param array $allowed_html Allowed HTML elements * @param array $allowed_protocols Allowed protocols to keep * @return string Content with fixed HTML tags */ function wp_kses_split( $string, $allowed_html, $allowed_protocols ) { global $pass_allowed_html, $pass_allowed_protocols; $pass_allowed_html = $allowed_html; $pass_allowed_protocols = $allowed_protocols; return preg_replace_callback( '%(|$))|(<[^>]*(>|$)|>)%', '_wp_kses_split_callback', $string ); } /** * Callback for wp_kses_split. * * @since 3.1.0 * @access private */ function _wp_kses_split_callback( $match ) { global $pass_allowed_html, $pass_allowed_protocols; return wp_kses_split2( $match[0], $pass_allowed_html, $pass_allowed_protocols ); } /** * Callback for wp_kses_split for fixing malformed HTML tags. * * This function does a lot of work. It rejects some very malformed things like * <:::>. It returns an empty string, if the element isn't allowed (look ma, no * strip_tags()!). Otherwise it splits the tag into an element and an attribute * list. * * After the tag is split into an element and an attribute list, it is run * through another filter which will remove illegal attributes and once that is * completed, will be returned. * * @access private * @since 1.0.0 * @uses wp_kses_attr() * * @param string $string Content to filter * @param array $allowed_html Allowed HTML elements * @param array $allowed_protocols Allowed protocols to keep * @return string Fixed HTML element */ function wp_kses_split2($string, $allowed_html, $allowed_protocols) { $string = wp_kses_stripslashes($string); if (substr($string, 0, 1) != '<') return '>'; # It matched a ">" character if ( ''), '', $string ); while ( $string != ($newstring = wp_kses($string, $allowed_html, $allowed_protocols)) ) $string = $newstring; if ( $string == '' ) return ''; // prevent multiple dashes in comments $string = preg_replace('/--+/', '-', $string); // prevent three dashes closing a comment $string = preg_replace('/-$/', '', $string); return ""; } # Allow HTML comments if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9]+)([^>]*)>?$%', $string, $matches)) return ''; # It's seriously malformed $slash = trim($matches[1]); $elem = $matches[2]; $attrlist = $matches[3]; if ( ! is_array( $allowed_html ) ) $allowed_html = wp_kses_allowed_html( $allowed_html ); if ( ! isset($allowed_html[strtolower($elem)]) ) return ''; # They are using a not allowed HTML element if ($slash != '') return ""; # No attributes are allowed for closing elements return wp_kses_attr( $elem, $attrlist, $allowed_html, $allowed_protocols ); } /** * Removes all attributes, if none are allowed for this element. * * If some are allowed it calls wp_kses_hair() to split them further, and then * it builds up new HTML code from the data that kses_hair() returns. It also * removes "<" and ">" characters, if there are any left. One more thing it does * is to check if the tag has a closing XHTML slash, and if it does, it puts one * in the returned code as well. * * @since 1.0.0 * * @param string $element HTML element/tag * @param string $attr HTML attributes from HTML element to closing HTML element tag * @param array $allowed_html Allowed HTML elements * @param array $allowed_protocols Allowed protocols to keep * @return string Sanitized HTML element */ function wp_kses_attr($element, $attr, $allowed_html, $allowed_protocols) { # Is there a closing XHTML slash at the end of the attributes? if ( ! is_array( $allowed_html ) ) $allowed_html = wp_kses_allowed_html( $allowed_html ); $xhtml_slash = ''; if (preg_match('%\s*/\s*$%', $attr)) $xhtml_slash = ' /'; # Are any attributes allowed at all for this element? if ( ! isset($allowed_html[strtolower($element)]) || count($allowed_html[strtolower($element)]) == 0 ) return "<$element$xhtml_slash>"; # Split it $attrarr = wp_kses_hair($attr, $allowed_protocols); # Go through $attrarr, and save the allowed attributes for this element # in $attr2 $attr2 = ''; $allowed_attr = $allowed_html[strtolower($element)]; foreach ($attrarr as $arreach) { if ( ! isset( $allowed_attr[strtolower($arreach['name'])] ) ) continue; # the attribute is not allowed $current = $allowed_attr[strtolower($arreach['name'])]; if ( $current == '' ) continue; # the attribute is not allowed if ( strtolower( $arreach['name'] ) == 'style' ) { $orig_value = $arreach['value']; $value = safecss_filter_attr( $orig_value ); if ( empty( $value ) ) continue; $arreach['value'] = $value; $arreach['whole'] = str_replace( $orig_value, $value, $arreach['whole'] ); } if ( ! is_array($current) ) { $attr2 .= ' '.$arreach['whole']; # there are no checks } else { # there are some checks $ok = true; foreach ($current as $currkey => $currval) { if ( ! wp_kses_check_attr_val($arreach['value'], $arreach['vless'], $currkey, $currval) ) { $ok = false; break; } } if ( $ok ) $attr2 .= ' '.$arreach['whole']; # it passed them } # if !is_array($current) } # foreach # Remove any "<" or ">" characters $attr2 = preg_replace('/[<>]/', '', $attr2); return "<$element$attr2$xhtml_slash>"; } /** * Builds an attribute list from string containing attributes. * * This function does a lot of work. It parses an attribute list into an array * with attribute data, and tries to do the right thing even if it gets weird * input. It will add quotes around attribute values that don't have any quotes * or apostrophes around them, to make it easier to produce HTML code that will * conform to W3C's HTML specification. It will also remove bad URL protocols * from attribute values. It also reduces duplicate attributes by using the * attribute defined first (foo='bar' foo='baz' will result in foo='bar'). * * @since 1.0.0 * * @param string $attr Attribute list from HTML element to closing HTML element tag * @param array $allowed_protocols Allowed protocols to keep * @return array List of attributes after parsing */ function wp_kses_hair($attr, $allowed_protocols) { $attrarr = array(); $mode = 0; $attrname = ''; $uris = array('xmlns', 'profile', 'href', 'src', 'cite', 'classid', 'codebase', 'data', 'usemap', 'longdesc', 'action'); # Loop through the whole attribute list while (strlen($attr) != 0) { $working = 0; # Was the last operation successful? switch ($mode) { case 0 : # attribute name, href for instance if ( preg_match('/^([-a-zA-Z:]+)/', $attr, $match ) ) { $attrname = $match[1]; $working = $mode = 1; $attr = preg_replace( '/^[-a-zA-Z:]+/', '', $attr ); } break; case 1 : # equals sign or valueless ("selected") if (preg_match('/^\s*=\s*/', $attr)) # equals sign { $working = 1; $mode = 2; $attr = preg_replace('/^\s*=\s*/', '', $attr); break; } if (preg_match('/^\s+/', $attr)) # valueless { $working = 1; $mode = 0; if(false === array_key_exists($attrname, $attrarr)) { $attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y'); } $attr = preg_replace('/^\s+/', '', $attr); } break; case 2 : # attribute value, a URL after href= for instance if (preg_match('%^"([^"]*)"(\s+|/?$)%', $attr, $match)) # "value" { $thisval = $match[1]; if ( in_array(strtolower($attrname), $uris) ) $thisval = wp_kses_bad_protocol($thisval, $allowed_protocols); if(false === array_key_exists($attrname, $attrarr)) { $attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n'); } $working = 1; $mode = 0; $attr = preg_replace('/^"[^"]*"(\s+|$)/', '', $attr); break; } if (preg_match("%^'([^']*)'(\s+|/?$)%", $attr, $match)) # 'value' { $thisval = $match[1]; if ( in_array(strtolower($attrname), $uris) ) $thisval = wp_kses_bad_protocol($thisval, $allowed_protocols); if(false === array_key_exists($attrname, $attrarr)) { $attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname='$thisval'", 'vless' => 'n'); } $working = 1; $mode = 0; $attr = preg_replace("/^'[^']*'(\s+|$)/", '', $attr); break; } if (preg_match("%^([^\s\"']+)(\s+|/?$)%", $attr, $match)) # value { $thisval = $match[1]; if ( in_array(strtolower($attrname), $uris) ) $thisval = wp_kses_bad_protocol($thisval, $allowed_protocols); if(false === array_key_exists($attrname, $attrarr)) { $attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n'); } # We add quotes to conform to W3C's HTML spec. $working = 1; $mode = 0; $attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr); } break; } # switch if ($working == 0) # not well formed, remove and try again { $attr = wp_kses_html_error($attr); $mode = 0; } } # while if ($mode == 1 && false === array_key_exists($attrname, $attrarr)) # special case, for when the attribute list ends with a valueless # attribute like "selected" $attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y'); return $attrarr; } /** * Performs different checks for attribute values. * * The currently implemented checks are "maxlen", "minlen", "maxval", "minval" * and "valueless". * * @since 1.0.0 * * @param string $value Attribute value * @param string $vless Whether the value is valueless. Use 'y' or 'n' * @param string $checkname What $checkvalue is checking for. * @param mixed $checkvalue What constraint the value should pass * @return bool Whether check passes */ function wp_kses_check_attr_val($value, $vless, $checkname, $checkvalue) { $ok = true; switch (strtolower($checkname)) { case 'maxlen' : # The maxlen check makes sure that the attribute value has a length not # greater than the given value. This can be used to avoid Buffer Overflows # in WWW clients and various Internet servers. if (strlen($value) > $checkvalue) $ok = false; break; case 'minlen' : # The minlen check makes sure that the attribute value has a length not # smaller than the given value. if (strlen($value) < $checkvalue) $ok = false; break; case 'maxval' : # The maxval check does two things: it checks that the attribute value is # an integer from 0 and up, without an excessive amount of zeroes or # whitespace (to avoid Buffer Overflows). It also checks that the attribute # value is not greater than the given value. # This check can be used to avoid Denial of Service attacks. if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value)) $ok = false; if ($value > $checkvalue) $ok = false; break; case 'minval' : # The minval check makes sure that the attribute value is a positive integer, # and that it is not smaller than the given value. if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value)) $ok = false; if ($value < $checkvalue) $ok = false; break; case 'valueless' : # The valueless check makes sure if the attribute has a value # (like ) or not (