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From:   Jeff Xu <jeffxu@google.com>
Date:   Tue, 16 May 2023 15:23:44 -0700
Message-ID: <CALmYWFujMVFLWDMMkdvWDDpXm+Z=b2vXapX1-2g1qe-qePMyhg@mail.gmail.com>
Subject: Re: [PATCH 3/6] PKEY: Apply PKEY_ENFORCE_API to mprotect
To:     Kees Cook <keescook@chromium.org>
Cc:     jeffxu@chromium.org, dave.hansen@intel.com, luto@kernel.org,
        jorgelo@chromium.org, groeck@chromium.org, jannh@google.com,
        sroettger@google.com, akpm@linux-foundation.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-mm@kvack.org, linux-hardening@vger.kernel.org
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On Tue, May 16, 2023 at 1:07=E2=80=AFPM Kees Cook <keescook@chromium.org> w=
rote:
>
> On Mon, May 15, 2023 at 01:05:49PM +0000, jeffxu@chromium.org wrote:
> > From: Jeff Xu <jeffxu@google.com>
> >
> > This patch enables PKEY_ENFORCE_API for the mprotect and
> > mprotect_pkey syscalls.
>
> All callers are from userspace -- this change looks like a no-op?
>
Yes. All callers are from user space now.
I am thinking about the future when someone adds a caller in kernel
code and may miss the check.
This is also consistent with munmap and other syscalls I plan to change.
There are comments on do_mprotect_pkey() to describe how this flag is used.


> -Kees
>
> --
> Kees Cook