Tag Archives: PHP programming language

Zend_Validate_Alnum Doesn’t Work Correctly

PHP, zend framework, , , , ,

Zend Framework’s Zend_Validate

I’m used to validate the form in a typical Zend Framework application with Zend_Validate or course. It gives you the absolute power to use the build in classes for standard validation, as well as write your custom validation classes.

The problem I had was a bit odd! Zend_Validate_Alnum is supposed to filter all characters and numbers, but what about non Latin symbols!? The project I’m working on is multilingual and there are eight languages, including Arabic, Chinese and Russian! All these were incorrectly !not validated by Zend_Validate_Alnum, although there were only letters and numbers!

In fact whatever the string encoding was – it doesn’t seem to work! Perhaps I’m wrong, but so far this is the situation.

Recent Update

After few test I figured out the problem was not in Zend_Validate at all! My mistake the solution is:

iconv_set_encoding('input_encoding', 'UTF-8');
iconv_set_encoding('output_encoding', 'UTF-8');
iconv_set_encoding('internal_encoding', 'UTF-8');

Zend_Http_Client and Case Sensitivity

micro tutorial, PHP, zend framework, , , , , , ,

Recently I posted about Zend_Http_Client and the ability to check a request HEAD or GET. It is, as everything in Zend Framework, extremely easy to adopt and use, but today I experienced some “strnage” problems!

As I wrote some lines of code,

<?php
....
$client = new Zend_Http_Client('uri_path');
$request = $client->request('head');
...
?>

so far so good, everything worked just perfect until I deployed the “working” code on the production server. Than odd enough some requests just crashed. Not all – just some of them.

Another strange thing was that no exception was thrown.

Maybe using more my intuition instead of my brain I just tried to request the head using capital letter – HEAD. And as everything was strange enough, yet again this solution happened to be working! That solved my problem.

<?php
....
$client = new Zend_Http_Client('uri_path');
$request = $client->request('HEAD');
...
?>

Secure Forms with Zend Framework

micro tutorial, PHP, zend framework, , , , , , , , , , ,

Maybe the correct title is not “with Zend Framework”, but “with PHP”, because the general approach I used is purely PHP and no Zend Framework dependency is used. However let me mention that ZF allows you to build forms with Zend_Form, which gives you an abstraction over the HTML forms with many goodies like validation, filtering and protection.

Zend_Form and Zend_Form_Element_Hash

Although the technique I’m using is doing the same thing, note that in ZF there’s a Zend_Form_Element_Hash which generates and validates the form, thus protecting you from CSRF attacks. The thing is that I didn’t use it because the form I’m protecting is not generated with Zend_Form, and I cannot benefit from everything ZF is giving to me. However you can easily reproduce the basic strategy with every form and every framework till it’s written in PHP.

What’s the solution?

It’s pretty simple and it’s described many many times around the web, simply generate a random hash, a possible solution is to use uniqid in combination with mt_rand and md5, thus you’d get quite strong hash.

Step two is to pass this generated hash, also stored in the session in a hidden value of the form. Of course now the most asked question is: but that’s visible to the source and thus everybody will have a valid hash.

There’s the trick. OK everybody will have a valid hash, but on submit the hash is validated against the SESSION variable, and as you know the session is specified between the browser (client) and the web server. Although the attacker may have a valid hash he must execute the attacking script from the same domain, possibly with the same browser, which makes the task rather difficult.

An Example

Let me show a breve example, it may help make things clearer.

1. First step – start the session

<?php
session_start();
?>

2. Second step – validate the form against the $_SESSION and generate a valid token

<?php
if (isset($_POST['name']) && $_POST['token'] == $_SESSION['token'])
    echo $_POST['name'];
else
    echo 'dont hack';
 
$_SESSION['token'] = md5(uniqid('test', true));
?>

3. Third step – make a form

<form method="POST" action="">
<input type="hidden" value="<?php echo $_SESSION['token'] ?>" name="token" />
<input type="text" name="name" value="stoimen" />
<input type="submit" name="submit" />
</form>

Demo here.

For more to test this you may try to make the same form somewhere else on the web and to point the action to http://www.stoimen.com/projects/php.secure.forms/! Without the session validation it’s absolutely sure you can post on the attacked server.

P.S. Now I’ve to admit that this have nothing to do with Zend Framework, however it’s good practice and thus may be used with every framework.

Send Mail with Zend Framework

PHP, zend framework, , , , , , , , , , , , ,

Simple, but Doesn’t Work!

It may sound strange, because all this is quite well documented in the Zend Framework documentation. Indeed it’s very very simple and all is done only by few lines of code.

$mail = new Zend_Mail();
$mail->setFrom('sender@example.com');
$mail->setBodyHtml('some message - it may be html formatted text');
$mail->addTo('recipient@example.com', 'recipient');
$mail->setSubject('subject');
$mail->send();

Even it look simple though, it may not work on your localhost while you’re trying to make it work! Because you’ve to have sendmail setup. And in Zend Framework sendmail is the default transport protocol for sending mails.

What You Have to Do to Make it Work?

Actually you’ve simply to add a transport protocol, just like that:

$tr = new Zend_Mail_Transport_Smtp('smtp.example.com',
                    array('auth' => 'login',
                             'username' => 'username',
                             'password' => 'password'));
Zend_Mail::setDefaultTransport($tr);

Where Did I Get These?

Well look at your favorite mail account you probably use every day. It may be hosted in GMail or wherever, but there are some configurations you have to port under Zend’s code and everything will be just fine until you develop the app!