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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Sat, 2 Dec 2017 08:51:52 +0000
Message-ID: <CAKv+Gu-fHg44tgEV1+EjA+mm_DreMgiZc0nTp3QcvNSfX1Pv1A@mail.gmail.com>
Subject: Re: [GIT PULL] hash addresses printed with %p
To: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "Tobin C. Harding" <me@tobin.cc>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        LKML <linux-kernel@vger.kernel.org>,
        "linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>
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On 1 December 2017 at 16:33, Kees Cook <keescook@chromium.org> wrote:
> On Fri, Dec 1, 2017 at 7:34 AM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
>
>> And isn't there a specific %p modifier you should use for a kernel
>> pointer.  I've lost the thread here for what should, or should not, be
>> done for kernel pointers these days based on the long email discussion.
>
> Current implementation to bypass the hashing is %px. (Though perhaps
> all %px usage should include a comment with a justification?)
>

In this case, we're always dealing with u64 types regardless of the
pointer size and physical address size. So I am leaning towards
retaining the %llx, and only updating the sysfs node permissions.