Re: [PATCH] lib/vsprintf: add %pT[C012] format specifier

From: Kees Cook
Date: Fri Jan 03 2014 - 12:49:17 EST


On Fri, Jan 3, 2014 at 9:39 AM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Fri, 2014-01-03 at 09:08 -0800, Kees Cook wrote:
>> I'm on board with the idea of embedding comm/pid/whatever,
>
> I still think the space reduction isn't worth the
> complication.
>
>> but I
>> either missed or do not understand why a second format-start character
>> is being added. I think this will complicate audits and maybe trigger
>> weird info leaks (imagine printing a string that was %-escaped, but
>> not 0x1A-escaped?)
>> Why not use % followed by 0x1A to be the start code, instead of just 0x1A?
>
> gcc would bleat an error for
> "unknown conversion type character 0x1a in format".

Oh right. Bleh. Which gets me back around to the original patch which
overloaded %p.

Hrmpf. Yeah, on the fence about this.

-Kees

--
Kees Cook
Chrome OS Security
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