Re: [PATCH 1/2] remove all uses of printf's %n

From: Kees Cook
Date: Mon Sep 16 2013 - 11:25:50 EST


On Mon, Sep 16, 2013 at 8:09 AM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Mon, 2013-09-16 at 07:59 -0700, Kees Cook wrote:
>> Perhaps instead of seq->count, there should be an access function?
>> seq_get_count(seq) or something?
>
> My thought was to add a seq_last_len()

That would mean growing the size of the seq_file structure and adding
instructions for all users. While I personally have no problem with
that, I worry others might. If we just use seq->count (or equivalent
function), then only those that want length will use it. I actually
think this uses fewer instructions than %n. Especially in the case
where seq_printf got replaced by seq_puts. :)

-Kees

--
Kees Cook
Chrome OS Security
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