Re: [RFC][PATCH] tracing, printk: Force no hashing when trace_printk() is used

[Kees Cook]

On Wed, Apr 4, 2018 at 12:49 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Tue, Apr 03, 2018 at 05:06:12PM -0400, Steven Rostedt wrote:
>> If you are concerned about attack surface, I could make it a bit more
>> difficult to tweak by malicious software. What about the patch below?
>> It would be much more difficult to modify this knob from an attack
>> vector.
>
> Not if you build using clang, because that doesn't support asm-goto and
> thus falls back to a simple runtime variable, which is exactly what Kees
> didn't want.

Nah, Clang will get asm-goto soon. I'm not worried about that. Besides
the "yay new target issue", I was concerned about Linus yelling about
seeing the knob added he specifically said he didn't want. :P

-Kees

-- 
Kees Cook
Pixel Security