I have created a form in my web application which has only a single text field and that field is posted to a PHP page using GET, but I am observing strange behavior. i.e. when I test it on my local server, the text is received as it was written in the text field, but when I upload it to my online server, the received string is escaped automatically means, all single quotes and double quotes are escaped. e.g. If I write It's not true... then on php side I will get
$comment = $_REQUEST["comm"];
print $comment;
//will print It\'s not true... on my online server
//will print It's not true... on my local server
I am yet unable to under stand why is it so? Is there any PHP setting for escaping Query Strings variables automatically?
You have "magic quotes" enabled. They're a terrible misfeature which are luckily being removed in the next version of PHP. The PHP manual has a guide to disabling them.
In short, you need to set the following configuration items to Off in your php.ini file:
magic_quotes_gpc
magic_quotes_runtime
magic_quotes_sybase
Specifically, your problem appears to be with magic_quotes_gpc - the "gpc" portion being short for "GET, POST, and COOKIE" - but it's good practice to keep all of them disabled.
Code will tell you every thing what you need..
function mysql_prep($value) {
$magic_quotes_active = get_magic_quotes_gpc();
$new_enough_php = function_exists("mysql_real_escape_string"); // i.e. PHP >= v4.3.0
if ($new_enough_php) { // PHP v4.3.0 or higher
// undo any magic quote effects so mysql_real_escape_string can do the work
if ($magic_quotes_active) {
$value = stripslashes($value);
}
$value = mysql_real_escape_string($value);
} else { // before PHP v4.3.0
// if magic quotes aren't already on then add slashes manually
if (!$magic_quotes_active) {
$value = addslashes($value);
}
// if magic quotes are active, then the slashes already exist
}
return $value;
}
create above function and pass-on values to this function
and then call the values like
$yourVar = mysql_prep($_POST['yourControlName']);
I hope you may get every thing explained via comments...
I think its a setting within the php.ini file. You can call a PHP function to disable it, but by then it's too late.
Related
1.I m a beginner .I want to know that "magic quote" is deprecated , so do I still need to include in my code?
2.urldecode(), urlencode(), htmlentities() etc do I still need to use ?
3.So, below code won't be needed if everything is fine.
/** Check for Magic Quotes and remove them **/
function stripSlashesDeep($value) {
$value = is_array($value) ? array_map(‘stripSlashesDeep’, $value) : stripslashes($value);
return $value;
}
function RemoveMagicQuotes() {
if ( get_magic_quotes_gpc() ) {
$_GET = stripSlashesDeep($_GET );
$_POST = stripSlashesDeep($_POST );
$_COOKIE = stripSlashesDeep($_COOKIE);
}
}
Magic quotes are removed and not useable anymore from PHP 5.3 and later, why? It is up to the programmer to handle and point it where it needs to go. It was meant to be a cure for MySQL injections but failed to do so.
This means that it is up to you that you to sanitize everything that the "user" can put his furry little claws on. This means at the very least: POST, GET and COOKIE requests.
But escaping like magic quotes did was meant to be used in combination with a database. Using PDO escaping is done automatically and you don't have to worry about it (IF properly used of course).
The other functions are still to be used at your own discretion.
I have users entering their name, as in: O'riley.
Before I enter this data into the MySQL DB, I run mysql_real_escape_string.
Problem is, when I then select this data for display and use later, it comes out as: O\'riley.
Obviously, this is the intended operation. What I'm wondering is if there's someway to be sure I can store it in the DB (still safely escaping possible malicious code), so that I don't have to use strip_slashes() on the output EVERY time I call the data throughout the entire web app? Or, am I missing something here?
Thanks.
UPDATE
Please refer to the comments in Deceze's answer.
No, it's not the intended operation to store the string as "O\'riley"; it should only be escaped in the query, but not stored this way. I'll guess that PHP puts in the backslash through Magic Quotes, and you escape it again to make it stick.
Disable Magic Quotes.
I personally always turn off magic quotes because it is doing something I haven't told it to do. If you dont have the ability to turn it off, consider including this code at the top of all of your pages.
if (get_magic_quotes_gpc()) {
function strip_array($var) {
return is_array($var)? array_map("strip_array", $var):stripslashes($var);
}
$_POST = strip_array($_POST);
$_SESSION = strip_array($_SESSION);
$_GET = strip_array($_GET);
}
If you have magic quotes disabled, and in the case that get_magic_quotes_gpc returned 1 and you did something like #Michael shows and this still occurs, magic quotes runtime may be enabled.
Magic quotes runtime will add slashes to strings when doing database queries and even when writing to files. To disable this in the currently executing script, do:
if(function_exists('get_magic_quotes_runtime') && get_magic_quotes_runtime())
{
set_magic_quotes_runtime(false);
}
You can also disable this configuration option through php.ini as well, if you can do so. However, if you can't disable it through php.ini permanently, you may need to add # before get_magic_quotes_runtime and set_magic_quotes_runtime as PHP may through E_DEPRECATED errors if error_reporting is set to log such errors (and this will get fairly annoying).
Alright, here's what you need to do. First, based on the comments, from other questions:
ISOLATE
You need to determine what is causing the problem. Is it the server? Is it some hidden code somewhere? What? Some programmers may include code like this on a configuration page:
<?php if (isset($_POST))
foreach ($_POST as $key => $value) $_POST[$key] = addslashes($value);
?>
So here are some checks to see if it is the server. This is about as solid a way of checking as possible. Create a NEW page. Leave it entirely blank and add this code:
<?php print_r($_POST); ?>
<form action="" method="POST">
<input type="text" name="test" value="O'riley" />
<input type="submit" name="submit" value="submit" />
</form>
Save it and load it in the browser. Hit submit. See if the slash is added still.
If it is still adding it, you need to troubleshoot your server / configuration. If it's a server you're paying for, you need to tell them to fix it or shove it. If it's your own server, then you're going to need to do some messing / googling to figure out how to turn off magic quotes.
If there are no quotes showing up, then there is definitely some code adding slashes to your post variables. It might not be as obvious as the code above, however. You need to run a search on your code for "addslashes", "mysql_real_escape_string", and possibly "str_replace". If you find one of these, you need to disable it. But be advised this may break other parts of your site that are assuming this action is taking place. You're other option for storing it in the database is to do a function similar to the code above, but instead, run stripslashes on it. Then you can run mysql_real_escape_string on it later. (A bit more unneeded overhead.)
Use
var_dump(get_magic_quotes_gpc());
somewhere near the actual use of the posted data to see if the Magic Quotes are really off.
Also some weird frameworks may add said quotes for you so grep your code for addslashes and other escape_string-like functions.
I would honestly suggest the use of PDO.
PDO employs the use of prepare and execute statements, which in turn adds security and removes some extra headache.
$pdo = new PDO();
$stm = $pdo->prepare('INSERT... (LastName) VALUES (:LastName)');
$stm->execute(array(':LastName' => "O'Rily"));
$stm->fetchAssoc(PDO::FETCH_ASSOC);
You no longer will need to worry about removing the escaping slashes as well as securing basic sql injection tactics.
It's possible magic quotes are turned on in your httpd.conf or in a virtual host declaration.
The exact location and file will depend on OS and distro. I'd check Apache configuration files for the php_flag setting.
Just use clean the data before inserting in to database,
function check_input($value)
{
if( get_magic_quotes_gpc() )
{
$value = stripslashes( $value );
}
//check if this function exists
if( function_exists( "mysql_real_escape_string" ) )
{
$value = mysql_real_escape_string( $value );
}
//for PHP version < 4.3.0 use addslashes
else
{
$value = addslashes( $value );
}
return $value;
}
$cleandata = check_input($value);
$sql = "INSERT INTO `table_name` SET `field_name`='".$cleandata."'";
While fetching the data and show into it use stripslashes($val)
Thank you everyone for the answers. I will award the +50 out, but I wanted to tell my real solution here, all which people did help with...
I was performing mysql_real_escape_string on all of the data AS SOON as it posted (before any processing). So, a slash was added to escape the ' character that was submitted. This, we know is normal.
However, there was no reason that the backslash \ should show up in the DB entry, right? The escape was there to be sure the ' was entered.
Turns out, AFTER escaping, I would then save the variable to be reloaded to the page in the session, in case the user had an error that PHP found while validating all of the form fields. In this case, the user's input (formerly O'riley was now printed to their screen as O\'riley. Then, the user didn't catch this - so they would often just fix their error that PHP caught during validation (unrelated to the name field), and thus the O\'riley would land in the database because mysql_real_escape_string would escape the characters.
Lesson:
When processing a form, FIRST save data for form-refill use. SECOND validate form fields. THIRD escape the data for processing into the database.
Or better yet, use PDO and avoid this =).
Comments welcome. THANKS ALL!
This question already has answers here:
Why are $_POST variables getting escaped in PHP?
(6 answers)
Closed 7 years ago.
I have a php page which contains a form.
Sometimes this page is submitted to itself (like when pics are uploaded).
I wouldn't want users to have to fill in every field again and again, so I use this as a value of a text-input inside the form:
value="<?php echo htmlentities(#$_POST['annonsera_headline'],ENT_COMPAT,'UTF-8');?>">
This works, except it adds a "\" sign before every double-quote...
For instance writing 19" wheels gives after page is submitted to itself:
19\" wheels
And if I don't even use htmlentities then everything after the quotes dissappears.
What is the problem here?
UPDATE:
Okay, so the prob is magic_quotes... This is enabled on my server...
Should I disable it? I have root access and it is my server :)
Whats the harm in disabling it?
Looks like you have magic quotes turned on. Use below condition using stripslashes with whatever text you want to process:
if(get_magic_quotes_gpc())
{
$your_text = stripslashes($your_text);
}
Now you can process $your_text variable normally.
Update:
Magic quotes are exaplained here. For well written code there is normally no harm in disabling it.
You likely have magic quotes turned on. You need to stripslashes() it as well.
Nicest way would be to wrap this in a function:
function get_string($array, $index, $default = null) {
if (isset($array[$index]) && strlen($value = trim($array[$index])) > 0) {
return get_magic_quotes_gpc() ? stripslashes($value) : $value;
} else {
return $default;
}
}
Which you can use as
$annonsera_headline = get_string($_POST, 'annonsera_headline');
By the way:
And if I don't even use htmlentities then everything after the quotes dissappears.
It's actually still there in the HTML source, you only don't see it. Do a View Source ;)
Update as per your update: the magic quotes is there to prevent SQL injection attacks in code of beginners. You see this often in 3rd party hosts. If you really know what you're doing in the code, then you can safely turn it off. But if you want to make your code distributable, then you'll really take this into account when gathering request parameters. For this the above function example is perfectly suitable (you only need to write simliar get_boolean(), get_number(), get_array() functions yourself).
Yes, you should disable magic quotes if you can. The feature is deprecated, and will likely go away completely in the future.
If you've relied on magic quotes for escaping data (for instance when inserting it into a database) you will may be opening yourself up to sql injection vulnerabilities if you disable it. You should check all your queries and make sure you're using mysql_real_escape_string().
I include the following file to undo magic quotes in apps that are deployed to servers not under my control.
<?php
set_magic_quotes_runtime(0);
function _remove_magic_quotes(&$input) {
if(is_array($input)) {
foreach(array_keys($input) as $key) _remove_magic_quotes($input[$key]);
}
else $input = stripslashes($input);
}
if(get_magic_quotes_gpc()) {
_remove_magic_quotes($_REQUEST);
_remove_magic_quotes($_GET);
_remove_magic_quotes($_POST);
_remove_magic_quotes($_COOKIE);
}
return true;
?>
This is actually a function of PHP trying to be security conscious, luckily there is an easy fix for it that looks something like this:
if (get_magic_quotes_gpc()) {$var = stripslashes($var);}
There isn't a huge problem in having it enabled, it comes down to personal preference. If you code will be moving servers much and you can't disable it through your php.ini file, it's best to use something as described above.
If you have access to your php.ini file and you want to change it, because you don't want to have to validate it each time you can add the following line to php.ini
magic_quotes_gpc = Off
Or the following to your .htaccess:
php_flag magic_quotes_gpc Off
Hope this helps clear things up.
Looks like your server is setup to use Magic Quotes.
You can fix it by stripping them with stripslashes, or better, by turning off Magic Quotes.
you shouldn't use htmlentities() when writing something to an input field value.
is magic_quotes enabled on your server? try out stripslashes before the output.
I have a simple PHP script I use to front-end an SQLite database. It's nothing fancy or complex. But I have noticed from looking at the records in the database that anything I enter in a form-field with double-quotes comes across in the form-processing as though I'd escaped the quotes with a backslash. So when I entered a record with the title:
British Light Utility Car 10HP "Tilly"
what shows up in the database is:
British Light Utility Car 10HP \"Tilly\"
I don't know where these are coming from, and what's worse, even using the following preg_replace doesn't seem to remove them:
$name = preg_replace('/\\"/', '"', $_REQUEST['kits_name']);
If I dump out $name, it still bears the unwanted \ characters.
You have most probably magic_quotes_gpc set to on in php.ini. If you want to avoid that and use your own regex, make a check like this:
if (get_magic_quotes_gpc())
{
$mytext = stripslashes($your_text);
}
// and your further code....
This means your server has magic_quotes_gpc enabled.
You can use ini_set() to disable this setting, or you can create a method to filter the $_REQUEST values()
function getRequest($key)
{
$val = $_REQUEST[$key];
if(get_magic_quotes_gpc() == 1) {
$val = stripslashes($val);
}
return $val;
}
echo getRequest('kits_name');
Is it possible magic quotes are enabled on the server?
You probably have magic quotes turned on.
You should disable these as it's bad practice and is deprecated.
View this doc to learn how to disable them.
Well because of lack of good answers.
As they said above, it is because magic quotes on.
You have to get rid of these slashes before inserting your data.
So, to get rid of it you can use either .htaccess (if any) with these settings
php_flag magic_quotes_gpc 0
php_flag magic_quotes_runtime 0
or make it manually, with code like this
if ( get_magic_quotes_gpc( ) ) {
$_GET = array_map_recursive('stripslashes', $_GET) ;
$_POST = array_map_recursive('stripslashes', $_POST) ;
$_COOKIE = array_map_recursive('stripslashes', $_COOKIE) ;
$_REQUEST = array_map_recursive('stripslashes', $_REQUEST) ;
if (isset($_SERVER['PHP_AUTH_USER'])) stripslashes($_SERVER['PHP_AUTH_USER']);
if (isset($_SERVER['PHP_AUTH_PW'])) stripslashes($_SERVER['PHP_AUTH_PW']);
}
if your php version doesn't support array_map_recursive function, you can use a recursive function like this one
function strips(&$el) {
if (is_array($el))
foreach($el as $k=>$v)
strips($el[$k]);
else $el = stripslashes($el);
}
or write your own one
You can use this code co cleanse your existing data
As for
If I dump out $name, it still bears
the unwanted \ characters.
it may be result of wrong use htmlspecialchars function
I just moved to a new hosting company and now whenever a string gets escaped using:
mysql_real_escape_string($str);
the slashes remain in the database. This is the first time I've ever seen this happen so none of my scripts use
stripslashes()
anymore.
This is on a CentOS 4.5 64bit running php 5.2.6 as fastcgi on a lighttpd 1.4 server. I've ensured that all magic_quotes options are off and the mysql client api is 5.0.51a.
I have the same issue on all 6 of my webservers.
Any help would be appreciated.
Thanks.
Edit:
Magic Quotes isn't on. Please don't recommend turning it off. THIS IS NOT THE ISSUE.
The host that you've moved probably has magic_quotes_runtime turned on. You can turn it off with set_magic_quotes_runtime(0).
Please turn off magic_quotes_runtime, and then change your code to use bind variables, rather than using the string escaping.
I can think of a number of things that could cause this. But it depends how you are invoking SQL queries. If you moved to use parameterized queries like with PDO, then escaping is unnecessary which means the call to mysql_real_escape_string is adding the extra slashes.
If you are using mysql_query etc. then there must be some code somewhere like addslashes which is doing this. This could either be before the data is going into the database, or after.
Also you say you have disabled magic quotes... if you haven't already, just do a hard check in the code with something like this:
echo htmlentities($_GET['value']); // or $_POST, whichever is appropriate
Make sure there are no slashes in that value, then also check this:
echo "Magic quotes is " . (get_magic_quotes_gpc() ? "ON" : "OFF");
I know you've said multiple times it isn't magic quotes, but for us guys trying to help we need to be sure you have checked the actual PHP output rather than just changing the config (which might not have worked).
it sounds as though you have magic quotes turned on. Turning it off isn't too hard: just create a file in your root directory called .htaccess and put this line in it:
php_flag magic_quotes off
If that's not possible for whatever reason, or you want to change your application to be able to handle magic quotes, use this technique:
Instead of accessing the request variables directly, use a function instead. That function can then check if magic quotes is on or off and strip out slashes accordingly. Simply running stripslashes() over everything won't work, because you'll get rid of slashes which you actually want.
function getVar($key) {
if (get_magic_quotes_gpc()) {
return stripslashes($_POST[$key]);
} else {
return $_POST[$key];
}
}
$x = getVar('x');
Now that you've got that, all your incoming variables are ready to be escaped again and mysql_real_escape_string() won't stuff them up.
the slashes remain in the database.
It means that your data gets double escaped.
There are 2 possible reasons:
magic quotes are on, despite of your feeling. Double-check it
There is some code in your application, that just mimic magic quotes behaviour, escaping all input.
This is very common misconception to have a general escaping function to "protect" all the incoming data. While it does no good at all, it also responsible for the cases like this.
Of so - just find that function and wipe it out.
You must probably have magic quotes turned on. Figuring out exactly how to turn it off can be quite a headache in PHP. While you can turn off magic quotes with set_magic_quotes_runtime(0), it isn't enough -- Magic quotes has already altered the input data at this point, so you must undo the change. Try with this snippet: http://talks.php.net/show/php-best-practices/26
Or better yet -- Disable magic quotes in php.ini, and any .htaccess files it may be set in.
I am not sure if I understand the issue correctly but I had a very same problem. No matter what I did the slashes were there when the string got escaped. Since I needed the inserted value to be in the exact same format as it was entered I used
htmlentities($inserted_value)
this will leave all inserted quote marks unescaped but harmless.
What might be the problem (it was with us) that you use mysql_real_escape_string() multiple times on the same var. When you use it multiple times, it will add the slashes.
Function below will correctly remove slashes before inserting into the database. I know you said magic quotes isn't on but something is adding slashes so try the following page and see the output. It'll help figure out where. Call with page.php?var=something-with'data_that;will`be|escaped
You will most likely see number three outputting more slashes than needed.
*Change the db details too.
<?php
$db = mysql_connect('host', 'user', 'pass');
$var = $_REQUEST['var'];
echo "1: $var :1<br />";
echo "2: ".stripslashes($var)." :2<br />";
echo "3: ".mysql_real_escape_string($var)." :3<br />";
echo "4: ".quote_smart($var)." :4<br />";
function quote_smart($value)
{
// Stripslashes is gpc on
if (get_magic_quotes_gpc())
{
$value = stripslashes($value);
}
// Quote if not a number or a numeric string
if ( !is_numeric($value) )
{
$value = mysql_real_escape_string($value);
}
return $value;
}
?>
mysql_real_escape_string($str); is supposed to do exactly that. it is meant to add backslashes to special characters especially when you want to pass the query to mysql. Take note that it also takes into account the character set of mysql.
For safer coding practices it would be good to edit your code and use stripslashes() to read out the data and remove the slashes.