[wp-hackers] the template tags and their default safe contexts
halukkaramete at gmail.com
Mon Feb 17 15:08:50 UTC 2014
Nikola, thank you for your reply.
I think, it would be necessary to create a matrix. and keep it handy...
sort of like...
the template tag safe-in-HTML safe-in-JS safe-in-Attr
safe-in-Textarea safe-in-HREF etc...
the_title() TRUE FALSE FALSE FALSE
On Sun, Feb 16, 2014 at 12:24 PM, Nikola Nikolov <nikolov.tmw at gmail.com>wrote:
> Hi Haluk,
> I see your point there and I guess that it's a matter of experience and
> being aware of things.
> Like being aware, that using the_title() is not safe to use within HTML
> attribute values. And to know that you should instead use esc_attr(
> get_the_title() ) - note the use of get_the_title() - using just
> the_title() won't work, since it will output it and not return it :)
> If you are aware of the escaping functions and in which cases they should
> be used, then that should give you a pretty good start. For instance if you
> want to escape text that will go in a textarea, you use esc_textarea().
> The best thing to do in my opinion when writing a theme or a plugin
> template is to use the correct escaping methods. This way I think that
> there are higher chances for the user to keep the escaping functions in
> place even if they tweak something on the template.
> On Sun, Feb 16, 2014 at 9:49 PM, Haluk Karamete <halukkaramete at gmail.com
> > Right off the bat, I'd like to express that this post of mine is not a
> > criticism of the current system, whatsoever. I know security is a complex
> > matter.
> > I'm only trying to get the hang of the issue I will be trying to point
> > below to pick your brains for ideas. That's all there is to it.
> > Having said that... here we go.
> > To make my point, I will just pick the template tag the_title().
> > The the_title() outputs the title.
> > And it's very easy to learn this fact, thanks to the codex and the
> > countless articles that are out there.
> > Since it's a WordPress core function, it's also pretty human to think
> > it should be safe to use it is as is. At least, I would not blame the
> > who think so, from the get-go.
> > But the fact of the matter is HTML is a complex thing. And dealing with
> > or simply writing valid HTML is even more complex. And most people can
> > easily get lost in this.
> > Take a look a this piece for instance...
> > It uses the_title() in a straightforward HTML.
> > <a href="#" title="<?php the_title(); ?>"><?php the_title(); ?></a>
> > The question is - Is it safe?
> > Obviously not...
> > Well, it is %50 secure. :)
> > The part within the HTML context ( which will eventually be falling in
> > between > and < ) is fine but the attribute part ( which will be falling
> > into title=" and " ) is not.
> > The the_title() call within the title attribute above is like a military
> > mines which is waiting to detonate for the wrong title.
> > Considering so many different contexts, and some many template_tags and
> > many esc_ functions, and millions of people out there, what do we do? or
> > should do?
> > And what do you guys do to sort this kind of matters when writing your
> > template files that outputs stuff? What handle or conventions do you use?
> > obviously, we do not have
> > the_title_js()
> > the_title_attr() and
> > the_title_html() versions for each and every template tag - which would
> > follow the esc_API context conventions in a one to one fashion ) as Mark
> > demonstrates here->
> > http://wordpress.tv/2011/01/29/mark-jaquith-theme-plugin-security/
> > I do know the fact that here, we have "the_title_attribute()" available
> > us, but hey, you just have to know that.
> > below. Which way do I go about it - and how do I know which one would be
> > allright?
> > Stackoverflow it?
> > <Script>
> > $the_title = '<?php the_title();?>';
> > $the_title = '<?php esc_js(the_title());?>';
> > $the_title = '<?php the_title_attribute();?>';
> > $the_title = '<?php esc_js(the_title_attribute());?>';
> > </script>
> > Is the only way to sort this out to know each-and-every-template_tag and
> > their safe output contexts? Or are there tips or conventions you guys use
> > to sort these things in a convenient way?
> > I'm just curious.
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