<?php
/// PARAMETER HANDLING ////////////////////////////////////////////////////
/**
* Returns a particular value for the named variable, taken from
* POST or GET. If the parameter doesn't exist then an error is
* thrown because we require this variable.
*
* This function should be used to initialise all required values
* in a script that are based on parameters. Usually it will be
* used like this:
* $id = required_param('id');
*
* @param string $parname the name of the page parameter we want
* @param int $type expected type of parameter
* @return mixed
*/
function required_param($parname, $type=PARAM_CLEAN) {
// detect_unchecked_vars addition
global $CFG;
if (!empty($CFG->detect_unchecked_vars)) {
global $UNCHECKED_VARS;
unset ($UNCHECKED_VARS->vars[$parname]);
}
if (isset($_POST[$parname])) { // POST has precedence
$param = $_POST[$parname];
} else if (isset($_GET[$parname])) {
$param = $_GET[$parname];
} else {
error('A required parameter ('.$parname.') was missing');
}
return clean_param($param, $type);
}
/**
* Returns a particular value for the named variable, taken from
* POST or GET, otherwise returning a given default.
*
* This function should be used to initialise all optional values
* in a script that are based on parameters. Usually it will be
* used like this:
* $name = optional_param('name', 'Fred');
*
* @param string $parname the name of the page parameter we want
* @param mixed $default the default value to return if nothing is found
* @param int $type expected type of parameter
* @return mixed
*/
function optional_param($parname, $default=NULL, $type=PARAM_CLEAN) {
// detect_unchecked_vars addition
global $CFG;
if (!empty($CFG->detect_unchecked_vars)) {
global $UNCHECKED_VARS;
unset ($UNCHECKED_VARS->vars[$parname]);
}
if (isset($_POST[$parname])) { // POST has precedence
$param = $_POST[$parname];
} else if (isset($_GET[$parname])) {
$param = $_GET[$parname];
} else {
return $default;
}
return clean_param($param, $type);
}
/**
* Used by {@link optional_param()} and {@link required_param()} to
* clean the variables and/or cast to specific types, based on
* an options field.
* <code>
* $course->format = clean_param($course->format, PARAM_ALPHA);
* $selectedgrade_item = clean_param($selectedgrade_item, PARAM_CLEAN);
* </code>
*
* @uses $CFG
* @uses PARAM_RAW
* @uses PARAM_CLEAN
* @uses PARAM_CLEANHTML
* @uses PARAM_INT
* @uses PARAM_NUMBER
* @uses PARAM_ALPHA
* @uses PARAM_ALPHANUM
* @uses PARAM_ALPHAEXT
* @uses PARAM_SEQUENCE
* @uses PARAM_BOOL
* @uses PARAM_NOTAGS
* @uses PARAM_TEXT
* @uses PARAM_SAFEDIR
* @uses PARAM_CLEANFILE
* @uses PARAM_FILE
* @uses PARAM_PATH
* @uses PARAM_HOST
* @uses PARAM_URL
* @uses PARAM_LOCALURL
* @uses PARAM_PEM
* @uses PARAM_BASE64
* @uses PARAM_TAG
* @uses PARAM_SEQUENCE
* @param mixed $param the variable we are cleaning
* @param int $type expected format of param after cleaning.
* @return mixed
*/
function clean_param($param, $type) {
global $CFG;
if (is_array($param)) { // Let's loop
$newparam = array();
foreach ($param as $key => $value) {
$newparam[$key] = clean_param($value, $type);
}
return $newparam;
}
switch ($type) {
case PARAM_RAW: // no cleaning at all
return $param;
case PARAM_CLEAN: // General HTML cleaning, try to use more specific type if possible
if (is_numeric($param)) {
return $param;
}
$param = stripslashes($param); // Needed for kses to work fine
$param = clean_text($param); // Sweep for scripts, etc
return addslashes($param); // Restore original request parameter slashes
case PARAM_CLEANHTML: // prepare html fragment for display, do not store it into db!!
$param = stripslashes($param); // Remove any slashes
$param = clean_text($param); // Sweep for scripts, etc
return trim($param);
case PARAM_INT:
return (int)$param; // Convert to integer
case PARAM_NUMBER:
return (float)$param; // Convert to integer
case PARAM_ALPHA: // Remove everything not a-z
return eregi_replace('[^a-zA-Z]', '', $param);
case PARAM_ALPHANUM: // Remove everything not a-zA-Z0-9
return eregi_replace('[^A-Za-z0-9]', '', $param);
case PARAM_ALPHAEXT: // Remove everything not a-zA-Z/_-
return eregi_replace('[^a-zA-Z/_-]', '', $param);
case PARAM_SEQUENCE: // Remove everything not 0-9,
return eregi_replace('[^0-9,]', '', $param);
case PARAM_BOOL: // Convert to 1 or 0
$tempstr = strtolower($param);
if ($tempstr == 'on' or $tempstr == 'yes' ) {
$param = 1;
} else if ($tempstr == 'off' or $tempstr == 'no') {
$param = 0;
} else {
$param = empty($param) ? 0 : 1;
}
return $param;
case PARAM_NOTAGS: // Strip all tags
return strip_tags($param);
case PARAM_TEXT: // leave only tags needed for multilang
return clean_param(strip_tags($param, '<lang><span>'), PARAM_CLEAN);
case PARAM_SAFEDIR: // Remove everything not a-zA-Z0-9_-
return eregi_replace('[^a-zA-Z0-9_-]', '', $param);
case PARAM_CLEANFILE: // allow only safe characters
return clean_filename($param);
case PARAM_FILE: // Strip all suspicious characters from filename
$param = ereg_replace('[[:cntrl:]]|[<>"`\|\':\\/]', '', $param);
$param = ereg_replace('\.\.+', '', $param);
if($param == '.') {
$param = '';
}
return $param;
case PARAM_PATH: // Strip all suspicious characters from file path
$param = str_replace('\\\'', '\'', $param);
$param = str_replace('\\"', '"', $param);
$param = str_replace('\\', '/', $param);
$param = ereg_replace('[[:cntrl:]]|[<>"`\|\':]', '', $param);
$param = ereg_replace('\.\.+', '', $param);
$param = ereg_replace('//+', '/', $param);
return ereg_replace('/(\./)+', '/', $param);
case PARAM_HOST: // allow FQDN or IPv4 dotted quad
$param = preg_replace('/[^\.\d\w-]/','', $param ); // only allowed chars
// match ipv4 dotted quad
if (preg_match('/(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/',$param, $match)){
// confirm values are ok
if ( $match[0] > 255
|| $match[1] > 255
|| $match[3] > 255
|| $match[4] > 255 ) {
// hmmm, what kind of dotted quad is this?
$param = '';
}
} elseif ( preg_match('/^[\w\d\.-]+$/', $param) // dots, hyphens, numbers
&& !preg_match('/^[\.-]/', $param) // no leading dots/hyphens
&& !preg_match('/[\.-]$/', $param) // no trailing dots/hyphens
) {
// all is ok - $param is respected
} else {
// all is not ok...
$param='';
}
return $param;
case PARAM_URL: // allow safe ftp, http, mailto urls
include_once($CFG->dirroot . '/lib/validateurlsyntax.php');
if (!empty($param) && validateUrlSyntax($param, 's?H?S?F?E?u-P-a?I?p?f?q?r?')) {
// all is ok, param is respected
} else {
$param =''; // not really ok
}
return $param;
case PARAM_LOCALURL: // allow http absolute, root relative and relative URLs within wwwroot
$param = clean_param($param, PARAM_URL);
if (!empty($param)) {
if (preg_match(':^/:', $param)) {
// root-relative, ok!
} elseif (preg_match('/^'.preg_quote($CFG->wwwroot, '/').'/i',$param)) {
// absolute, and matches our wwwroot
} else {
// relative - let's make sure there are no tricks
if (validateUrlSyntax($param, 's-u-P-a-p-f+q?r?')) {
// looks ok.
} else {
$param = '';
}
}
}
return $param;
case PARAM_PEM:
$param = trim($param);
// PEM formatted strings may contain letters/numbers and the symbols
// forward slash: /
// plus sign: +
// equal sign: =
// , surrounded by BEGIN and END CERTIFICATE prefix and suffixes
if (preg_match('/^-----BEGIN CERTIFICATE-----([\s\w\/\+=]+)-----END CERTIFICATE-----$/', trim($param), $matches)) {
list($wholething, $body) = $matches;
unset($wholething, $matches);
$b64 = clean_param($body, PARAM_BASE64);
if (!empty($b64)) {
return "-----BEGIN CERTIFICATE-----\n$b64\n-----END CERTIFICATE-----\n";
} else {
return '';
}
}
return '';
case PARAM_BASE64:
if (!empty($param)) {
// PEM formatted strings may contain letters/numbers and the symbols
// forward slash: /
// plus sign: +
// equal sign: =
if (0 >= preg_match('/^([\s\w\/\+=]+)$/', trim($param))) {
return '';
}
$lines = preg_split('/[\s]+/', $param, -1, PREG_SPLIT_NO_EMPTY);
// Each line of base64 encoded data must be 64 characters in
// length, except for the last line which may be less than (or
// equal to) 64 characters long.
for ($i=0, $j=count($lines); $i < $j; $i++) {
if ($i + 1 == $j) {
if (64 < strlen($lines[$i])) {
return '';
}
continue;
}
if (64 != strlen($lines[$i])) {
return '';
}
}
return implode("\n",$lines);
} else {
return '';
}
case PARAM_TAG:
//as long as magic_quotes_gpc is used, a backslash will be a
//problem, so remove *all* backslash.
$param = str_replace('\\', '', $param);
//convert many whitespace chars into one
$param = preg_replace('/\s+/', ' ', $param);
$textlib = textlib_get_instance();
$param = $textlib->substr(trim($param), 0, TAG_MAX_LENGTH);
return $param;
case PARAM_TAGLIST:
$tags = explode(',', $param);
$result = array();
foreach ($tags as $tag) {
$res = clean_param($tag, PARAM_TAG);
if ($res != '') {
$result[] = $res;
}
}
if ($result) {
return implode(',', $result);
} else {
return '';
}
default: // throw error, switched parameters in optional_param or another serious problem
error("Unknown parameter type: $type");
}
}
?>
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