get_magic_quotes_gpc
(PHP 4, PHP 5)
get_magic_quotes_gpc — Gets the current configuration setting of magic quotes gpc
Описание
int get_magic_quotes_gpc
( void
)
Returns the current configuration setting of magic_quotes_gpc
Keep in mind that the setting magic_quotes_gpc will not work at runtime.
For more information about magic_quotes, see this security section.
Возвращаемые значения
Returns 0 if magic quotes gpc are off, 1 otherwise.
Примеры
Пример #1 get_magic_quotes_gpc() example
<?php
echo get_magic_quotes_gpc(); // 1
echo $_POST['lastname']; // O\'reilly
echo addslashes($_POST['lastname']); // O\\\'reilly
if (!get_magic_quotes_gpc()) {
$lastname = addslashes($_POST['lastname']);
} else {
$lastname = $_POST['lastname'];
}
echo $lastname; // O\'reilly
$sql = "INSERT INTO lastnames (lastname) VALUES ('$lastname')";
?>
Примечания
Замечание: If the directive magic_quotes_sybase is ON it will completely override magic_quotes_gpc. So even when get_magic_quotes_gpc() returns TRUE neither double quotes, backslashes or NUL's will be escaped. Only single quotes will be escaped. In this case they'll look like: ''
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Коментарии
Please note, that when magic_quotes_gpc is set not only $_POST, $_GET, $_REQUEST, $_COOKIE arrays values are slashed. Actually every string value in $GLOBALS array is slashed, ie. $GLOBALS['_SERVER']['PATH_INFO'] (or $_SERVER['PATH_INFO']).Escaping of key-strings in GPC-arrays behave different to the escaping of their values.
First I expected that keys in submitted gpc-arrays are never escaped.
Anyway. After I saw escaped keys, I assumed they're escaped according to the settings of magic quotes.
... it's even worse...
It took me over 2 days of testing to figure out the exact behavior and creating two functions (one for each php-version) that strips slashes reliably from any array submitted to a script. Hope this saves someones time and nerves.
The following is true for $_GET- and $_POST-arrays. I hope other arrays affected by magic quotes behave equally.
I did not test the behavior for cases where magic_quotes_sybase is set.
== legend for possible case combinations ==
Px = php version we're using
P4 = php 4.3.9
P5 = php 5.0.2
MQ = MagicQuotes GPC
+MQ = magic quotes enabled
-MQ = magic quotes disabled
TL = TopLevel key
+TL = key is on top level (i.e. $_GET['myKey'])
-TL = key is nested within another array (i.e. $_GET['myList']['myKey'])
AK = ArrayKey
+AK = the value of the key is another array (i.e. is_array($_GET['myKey']) == true)
-AK = the value is a normal string (i.e. is_string($_GET['myKey']) == true)
== legend for possible results ==
KE = KeyEscaping
+KE = control chars are prefixed with a backslash
-KE = key is returned as submitted and needn't to be stripped
VE = ValueEscaping (doesn't apply for array as value)
+VE = control chars are prefixed with a backslash
-VE = value is returned as submitted and needn't to be stripped
== here we go - the following rules apply ==
1) P4 +MQ +AK +TL --> -KE
2) P4 +MQ +AK -TL --> +KE
3) P4 +MQ -AK +TL --> -KE +VE
4) P4 +MQ -AK -TL --> +KE +VE
5) P4 -MQ +AK +TL --> -KE
6) P4 -MQ +AK -TL --> -KE
7) P4 -MQ -AK +TL --> -KE -VE
8) P4 -MQ -AK -TL --> -KE -VE
9) P5 +MQ +AK +TL --> -KE
10) P5 +MQ +AK -TL --> +KE
11) P5 +MQ -AK +TL --> +KE +VE
12) P5 +MQ -AK -TL --> +KE +VE
13) P5 -MQ +AK +TL --> -KE
14) P5 -MQ +AK -TL --> -KE
15) P5 -MQ -AK +TL --> +KE -VE
16) P5 -MQ -AK -TL --> +KE -VE
17) The chars '.', ' ' are always replaced by '_' when used in keys.
Example (rule 15):
When running under php 5.0.2 having magic quotes disabled, gpc-keys on top level containing strings are escaped while their associated values are not.
== The following function will strip GPC-arrays for php 4.3.9 ==
<?php
function transcribe($aList, $aIsTopLevel = true) {
$gpcList = array();
$isMagic = get_magic_quotes_gpc();
foreach ($aList as $key => $value) {
$decodedKey = ($isMagic && !$aIsTopLevel)?stripslashes($key):$key;
if (is_array($value)) {
$decodedValue = transcribe($value, false);
} else {
$decodedValue = ($isMagic)?stripslashes($value):$value;
}
$gpcList[$decodedKey] = $decodedValue;
}
return $gpcList;
}
?>
== The following function will strip GPC-arrays for php 5.0.2 ==
<?php
function transcribe($aList, $aIsTopLevel = true) {
$gpcList = array();
$isMagic = get_magic_quotes_gpc();
foreach ($aList as $key => $value) {
if (is_array($value)) {
$decodedKey = ($isMagic && !$aIsTopLevel)?stripslashes($key):$key;
$decodedValue = transcribe($value, false);
} else {
$decodedKey = stripslashes($key);
$decodedValue = ($isMagic)?stripslashes($value):$value;
}
$gpcList[$decodedKey] = $decodedValue;
}
return $gpcList;
}
?>
Usage:
<?php
$unstrippedGET = transcribe($_GET);
$unstrippedPOST = transcribe($_POST);
?>
Maybe someone is willing to test those combinations for other php-versions and with magic_quotes_sybase set to 'on' - let me know.
Sorry for this huge amount of text, but it's complete. I was unable to compress the decision table more than this.
When you work with forms and databases you should use this concept:
1.When inserting the user input in DB escape $_POST/$_GET with add_slashes() or similar (to match the speciffic database escape rules)
$query='INSERT INTO users SET fullname="'.add_slashes($_POST['fullname']).'"';
insert_into_db($query);
2.When reading a previously submitted input from DB use html_special_chars to display an escaped result!
read_db_row('SELECT fullname FROM users');
echo '<input type="text" name="fullname" value="'.html_special_chars($db_row['fullname']).'" />
this way you safely store and work with the original(unescaped) data.
Re: php at kaiundina dot de (03-Feb-2005 02:18)
1. magic_quotes_gpc=on/off and magic_quotes_sybase=on/off
I made test and your function worked right.
These were the <input ... /> names I used:
name="a"
name="b.b b\b"
name="c[c.1]"
name="c[c 2]"
name="c[c\3]"
name="c.c c[c.' 4]"
name="c ' c[c"4]"
name="d"[d"1]"
(I used " because I don't know other way to put " into the name)
and the user-input value:
a ' " \ \' \" \\ a
2. > 17) The chars '.', ' ' are always replaced by '_' when used in keys.
This is true only for the top-level keys, such as "b.b b\b", "c.c c" and "c ' c" above. The second-level key "[c.' 4]" was not changed to [c_'_4] but was escaped acording to how magic_quites_XXX are set.
Tested on PHP 4.4.0.
These magic_quotes are really black magic :(
It'll be good to make test against $_SESSION, but I can't do it today.
Just a little correction:( Because of the ini_get function that may return a string value of "off" that evaluates to TRUE )
<?php
if(
( function_exists("get_magic_quotes_gpc") && get_magic_quotes_gpc() )
|| ( ini_get('magic_quotes_sybase') && ( strtolower(ini_get('magic_quotes_sybase')) != "off" ) )
){
foreach($_GET as $k => $v) $_GET[$k] = stripslashes($v);
foreach($_POST as $k => $v) $_POST[$k] = stripslashes($v);
foreach($_COOKIE as $k => $v) $_COOKIE[$k] = stripslashes($v);
}
?>
@ dot dot dot dot dot alexander at gmail dot com
I suggest replacing foreach by "stripslashes_deep":
Example #2 Using stripslashes() on an array on
<function.stripslashes>:
<?php
function stripslashes_deep($value)
{
$value = is_array($value) ?
array_map('stripslashes_deep', $value) :
stripslashes($value);
return $value;
}
?>
This gives:
<?php
if((function_exists("get_magic_quotes_gpc") && get_magic_quotes_gpc()) || (ini_get('magic_quotes_sybase') && (strtolower(ini_get('magic_quotes_sybase'))!="off")) ){
stripslashes_deep($_GET);
stripslashes_deep($_POST);
stripslashes_deep($_COOKIE);
}
?>
<?php
function stripper($stringvar){
if (1 == get_magic_quotes_gpc()){
$stringvar = stripslashes($stringvar);
}
return $stringvar;
}
?>
Usage:
<?php
$Body = stripper($rs->fields('Body'));
echo($Body);
?>
This checks if get_magic_quotes_gpc() is on and strips a string variable for output if its on. Useful if the dev server and live server are set up different.
Here's what I came up with to remove magic quotes from request data.
Replaces two single-quotes with one if magic_quotes_sybase are on, otherwise it just strips slashes.
Note that the `foreach` style makes this work only with PHP 5 and above.
<?php
// Strip magic quotes from request data.
if (function_exists('get_magic_quotes_gpc') && get_magic_quotes_gpc()) {
// Create lamba style unescaping function (for portability)
$quotes_sybase = strtolower(ini_get('magic_quotes_sybase'));
$unescape_function = (empty($quotes_sybase) || $quotes_sybase === 'off') ? 'stripslashes($value)' : 'str_replace("\'\'","\'",$value)';
$stripslashes_deep = create_function('&$value, $fn', '
if (is_string($value)) {
$value = ' . $unescape_function . ';
} else if (is_array($value)) {
foreach ($value as &$v) $fn($v, $fn);
}
');
// Unescape data
$stripslashes_deep($_POST, $stripslashes_deep);
$stripslashes_deep($_GET, $stripslashes_deep);
$stripslashes_deep($_COOKIE, $stripslashes_deep);
$stripslashes_deep($_REQUEST, $stripslashes_deep);
}
?>
> "If the directive magic_quotes_sybase is ON it will completely override magic_quotes_gpc."
This "note" is a bit misleading. magic_quotes_sybase will only override the escaping method used on Get/Post/Cookie data if magic_quotes_gpc is already enabled. If magic_quotes_gpc is not enabled then magic_quotes_sybase will have no effect here.
A few of the other comments are therefore incorrect in determining when to "stripslashes" from the input, by "stripping slashes" when either magic_quotes_gpc OR magic_quotes_sybase is enabled. You should only stripslashes() when magic_quotes_gpc is enabled since that is the only time when slashes are automatically added.
stripslashes() is also magic_quotes_sybase aware, so you don't need to do anything special (ie. write a custom function to handle this situation as another comment suggests) when magic_quotes_sybase is enabled. When magic_quotes_sybase is enabled, stripslashes() does not actually strip any slashes, but instead unescapes single-quotes that are escaped with single-quotes only.
magic_quotes_sybase does however influence the escaping (and unescaping) method used by addslashes() and stripslashes() respectively, regardless of whether magic_quotes_gpc (or magic_quotes_runtime) is enabled.