Re: POST action

On 7/28/13 9:23 PM, Paul M Foster wrote:

On Sun, Jul 28, 2013 at 08:46:06PM -0500, Larry Garfield wrote:

On 07/28/2013 12:38 PM, Ashley Sheridan wrote:

On Sun, 2013-07-28 at 13:37 -0400, Jim Giner wrote:

Never write your own form? I'm guilty - oh, so guilty. What exactly is a 'security hardened' form?

- All forms need a valid CSRF token to avoid CSRF attacks. This needs to be matched between the submitted form and server-maintained state. Do all of your forms have that? Every single one? (A GET lookup form like a search box doesn't need it, but anything with POST does, I'd argue.)

Yes. I wrote a "bless" class just for this purpose, which I use on all form pages.

- Do you have a select element? Do you have error handling for when someone submits a value for that wasn't one of the option elements?

Yes, since I realize that what comes back to me may bear no resemblence to what I coded in HTML. Thus, I always check for allowed "SELECT" values.

- Your text input field has a max length of 20. Does your code return an error when the user enters a string of 100 characters?

Yes. Same answer. Putting a max length of 20 in the HTML works okay, but the user could still submit something much longer if they are attempting to hack the page. Thus I always check for max characters on the return.

- Are you checking for weird edge-case-y character encoding issues? (Some versions of some browsers can be hacked by sending UTF-7 instead of UTF-8 for certain parts of the request. I don't fully understand that stuff myself, either.)

No I don't check for this.

- You have a "number" field (HTML5). Does your PHP code handle someone submitting a string anyway?

I don't use HTML5 tags like this, since they are not universally supported. However, I check that numbers look like numbers on return and strings look like strings on return. PHP has built-in functions for this. All this is part of my validation class.

- Are you checking all of those correctly every single time you write a form?

Except as noted above. This is all home-grown, using native PHP functions designed to do these things, and classes I've written. I carefully examine each field when writing the POST-handling code with the idea in mind that no matter what the HTML says, the return value must conform to what *I* think it should be. No MVC framework written by others (though I do conform to MVC paradigm). Paul

Then you're not writing your own form tags from the sound of it; you're writing your own Form API. Still an improvements. :-) Now, let's talk about form accessibility... --Larry Garfield