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From: "Roberts, William C" <william.c.roberts@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
        "Tobin C. Harding" <me@tobin.cc>
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Subject: RE: [PATCH 0/3] add %pX specifier
Thread-Topic: [PATCH 0/3] add %pX specifier
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Date: Fri, 13 Oct 2017 17:54:17 +0000
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> -----Original Message-----
> From: linus971@gmail.com [mailto:linus971@gmail.com] On Behalf Of Linus
> Torvalds
> Sent: Tuesday, October 10, 2017 4:17 PM
> To: Tobin C. Harding <me@tobin.cc>
> Cc: kernel-hardening@lists.openwall.com; KVM list <kvm@vger.kernel.org>;
> Linux Kernel Mailing List <linux-kernel@vger.kernel.org>; Kees Cook
> <keescook@chromium.org>; Paolo Bonzini <pbonzini@redhat.com>; Tycho
> Andersen <tycho@docker.com>; Roberts, William C
> <william.c.roberts@intel.com>; Tejun Heo <tj@kernel.org>; Jordan Glover
> <Golden_Miller83@protonmail.ch>; Greg KH <gregkh@linuxfoundation.org>;
> Petr Mladek <pmladek@suse.com>; Joe Perches <joe@perches.com>; Ian
> Campbell <ijc@hellion.org.uk>; Sergey Senozhatsky
> <sergey.senozhatsky@gmail.com>; Catalin Marinas <catalin.marinas@arm.com>;
> Will Deacon <will.deacon@arm.com>; Steven Rostedt <rostedt@goodmis.org>;
> Chris Fries <cfries@google.com>; Dave Weinstein <olorin@google.com>; Daniel
> Micay <danielmicay@gmail.com>; Djalal Harouni <tixxdz@gmail.com>
> Subject: Re: [PATCH 0/3] add %pX specifier
> 
> On Tue, Oct 10, 2017 at 4:09 PM, Tobin C. Harding <me@tobin.cc> wrote:
> >
> > This patch is a softer version of Linus' suggestion because it does
> > not change the behaviour of the %p specifier. I don't see the benefit
> > in making such a breaking change without addressing the issue of %x (and I
> don't the balls to right now).
> 
> The thing is, this continues to have the exact same issue that %pK has
> - because it is opt-in, effectively nobody will actually use it.
> 
> That's why I would suggest that if we do this way, we really change %p and %pa
> to use the hashed value, to convert *everybody*. And then people who have a
> good reason to actually expose the pointer have to do the extra work and opt
> out.

Yes we cannot make this opt in or there is really no point in doing it. %pK and mistakes
got us here to this point. I see there is multiple threads, this getting really fun to follow.

> 
>                   Linus