Security Advice Needed

Profile picture of the author Kirk Ward by Kirk Ward Posted: 02/11/2013
I am creating a wordpress multiser or network site with forms on each blogs dashboard where the admin can enter content.

There are two textare boxes and one text input box in the form and it is being saved as post metadata using a _POST action.

What would you suggest I use to sanitize the data that is being saved? And, where would this sanitizing function go?

Thanks,
#advice #needed #security

  • Profile picture of the author SteveSRS
    SteveSRS
    Check out PDO it auto sanitizes (when used correctly!!)
  • Profile picture of the author Kirk Ward
    Kirk Ward
    Being one old non-coder, PDO looks to be way over my head.

    I was reading the Wordpress Codex for update_post() and noted that it runs any submission through kses. Does update_meta() run data submitted through kses?
  • Profile picture of the author SteveJohnson
    SteveJohnson
    This page: Data Validation « WordPress Codex discusses data validation in WP. There are a number of WP functions that will do what you need. Also, you should check the docs on WP nonces: WordPress Nonces « WordPress Codex. Your form processing function verifies the nonce to ensure that whatever submitted the form data has the authority to do so.

    Also, it sounds like you're trying to create a dashboard widget? If so, this page: Dashboard Widgets API « WordPress Codex might help.

    Does update_meta() run data submitted through kses?
    No, it does not. The only sanitization of data occurs when the UPDATE statement is prepared. You need to do your own validation first.
  • Profile picture of the author Kirk Ward
    Kirk Ward
    Thanks Steve,

    I've been struggling, trying to figure out what to do and am wondering if I could create a function and have the sanitize_meta function clean up things for me. Seems that is called when the update_meta function is called.

    What you think?
  • Profile picture of the author SteveJohnson
    SteveJohnson
    The sanitize_meta function is just an empty hook, it doesn't do anything on its own. You build your own sanitizing filter (function) for a specific meta key, and run it by adding the filter to the sanitize_meta function. You would use this kind of filter most often when you're needing to validate/sanitize a custom field that a user would enter.

    In your case, it would be easier to just build your filter into the function that saves the meta data.

    Let's say you want to allow only the limited HTML that is allowed in a comment. It's as simple as this:

    $meta_data = wp_kses_data( $_POST['meta_data'] );
    update_post_meta( $post->ID, 'meta_key', $meta_data );

    ( Function Reference/wp kses data « WordPress Codex )

    It's kind of difficult to guide you without seeing exactly what you're doing.
  • Profile picture of the author lordspace
    lordspace
    For my fields I use strip_tags and trim to make sure HTML tags are removed.
    Is it text content that goes in the text fields?
  • Profile picture of the author SteveSRS
    SteveSRS
    lordspace that is def not enough for insertion in a database...
  • Profile picture of the author SteveJohnson
    SteveJohnson
    Originally Posted by SteveSRS View Post

    lordspace that is def not enough for insertion in a database...
    It is if you're using built-in WP routines to update the db, as Kirk is.
  • Profile picture of the author Kirk Ward
    Kirk Ward
    Originally Posted by SteveJohnson View Post

    t's kind of difficult to guide you without seeing exactly what you're doing.
    Sorry I've not answered sooner. I've been trying to understand Stripe (http://stripe.com)

    I tried posting my code in here, but it appears I can't do the bbcode for code.

    Okay if I PM you and send what I think is the pertinent code either privately or in an email?

    I'm not sure whether to put the sanitize function in the functions.php or the include file. Take a look at the code and you'll see why ... one of the things I do is switch between blogs a bit.
  • Profile picture of the author Kirk Ward
    Kirk Ward
    Originally Posted by lordspace View Post

    For my fields I use strip_tags and trim to make sure HTML tags are removed.
    Is it text content that goes in the text fields?
    Yes, it is text only for two textarea fields and numberic only for the text input box.

    numberic?

    I need to learn to spell when it is four hours past my old geezer bedtime.
  • Profile picture of the author SteveJohnson
    SteveJohnson
    Originally Posted by Kirk Ward View Post

    Sorry I've not answered sooner. I've been trying to understand Stripe (http://stripe.com)

    I tried posting my code in here, but it appears I can't do the bbcode for code.

    Okay if I PM you and send what I think is the pertinent code either privately or in an email?

    I'm not sure whether to put the sanitize function in the functions.php or the include file. Take a look at the code and you'll see why ... one of the things I do is switch between blogs a bit.
    Would be better if you were to supply the complete plugin or theme folder that you're working on, that lets me see everything in context. Just zip up the folder and send it in a pm to me (I think you can include files in PMs? Dunno for sure). I'll PM you my email addr to use if that won't work.
  • Profile picture of the author Kirk Ward
    Kirk Ward
    Originally Posted by SteveJohnson View Post

    Would be better if you were to supply the complete plugin or theme folder that you're working on, that lets me see everything in context. Just zip up the folder and send it in a pm to me (I think you can include files in PMs? Dunno for sure). I'll PM you my email addr to use if that won't work.
    I'd thank you two or three times if the WF software would let me.

    Files sent.

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