Re: Re: Security, Late Nights and Overall Paranoia

The point is.. If you for example only allow <i><u> and <b> doing this with bbcode would require extra cpu-cycles to convert [i] to <i> I don't really agree with this, because I think escaping the html + replacing bbcode would require less cpu cycles then scanning the string for invalid html and escaping them. Maybe someone has the time to benchmark this? Whatever the outcome will be, I would still prefer <i> over [i] because I'm a standards guy =) regards, Evert Jonathan Kart wrote:

I've been loosely following this thread, and have a question now. Isn't one advantage of a bbcode type solution that you can more easily avoid session hijacking vis cross site scripting? If you allow html, then you open the door for people to add eventhandlers. I guess you could always strip them, but it seems like for simple stuff bbcode isn't a bad solution. On 7/11/05, Richard Davey <rich@launchcode.co.uk> wrote:

Hello Greg, Monday, July 11, 2005, 5:06:51 PM, you wrote: GD> I wouldn't know, <span> isn't one of the tags I allow. If you stick to the plain vanilla HTML tags such as i, b, u, etc then BBCode is pointless - I agreed on this with you several posts ago. I don't however use it just for that, I use it to let thousands of kids add a little sparkle to their messages/profiles with colours, images, etc -- without them having to have good CSS/HTML knowledge (most of them could handle a font tag, but that'd break my XHTML Trans). This is the point I argued all along to which I get "it's not really a security benefit" (no, it's a user benefit) and it's a "misuse of cpu cycles". For people I hold in such high regard, I'm ashamed at the lot of you :) GD> I don't bother with perfect tag validation, and I doubt the phpbb GD> bbcode people do either since they average about 2-3 exploits a GD> month on Bugtraq. Not that I'd let an install of phpBB anywhere near a site I run, they didn't invent BBCode, and in all fairness to those guys the majority of their exploits are elsewhere. GD> I allow a specific set of safe html tags and I provide a preview GD> function. Even after that, if the user goofs up I allow a specific GD> time span in which to edit the post to correct the goof. Ditto. I just don't force them to use HTML. Best regards, Richard Davey -- http://www.launchcode.co.uk - PHP Development Services "I do not fear computers. I fear the lack of them." - Isaac Asimov -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php