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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Kees Cook <keescook@chromium.org>
Cc: Rik van Riel <riel@redhat.com>,
	Laura Abbott <labbott@fedoraproject.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	kernel test robot <xiaolong.ye@intel.com>
Subject: Re: [PATCH] usercopy: Skip multi-page bounds checking on SLOB
Date: Fri, 19 Aug 2016 13:07:53 -0700	[thread overview]
Message-ID: <CA+55aFwVhy59d0OH1En_Z7agsQAkW41QoOXAptr9eQt25VMRNQ@mail.gmail.com> (raw)
In-Reply-To: <CAGXu5jJi4qMD5p38i5NuR7fh38m7mp+7qZNXgUiGNRTaLtYoxA@mail.gmail.com>

On Fri, Aug 19, 2016 at 1:03 PM, Kees Cook <keescook@chromium.org> wrote:
>
> Okay, I can live with that. I'd hoped to keep the general split
> between the other checks (i.e. stack) and the allocator, but if this
> is preferred, that's cool. :)

If it had been anything else than SLOB, I might have cared. As it was,
I didn't think it was worth worrying about SLOB together with
hardening.

It was also about the __check_object_size() modification just being
very ugly, with a "return NULL" in the middle of the function. I
looked at just splitting that function up, and having a part of it
that would just go away when the slab allocator wasn't smart enough,
but that would have been a bigger change that I'm not interested in
taking right now. So it could be a future improvement, and maybe we
could then re-instate SLOB with partial checking.

             Linus

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      reply	other threads:[~2016-08-19 20:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17 22:29 [PATCH] usercopy: Skip multi-page bounds checking on SLOB Kees Cook
2016-08-18 14:21 ` Rik van Riel
2016-08-18 17:42   ` Linus Torvalds
2016-08-18 18:02     ` Rik van Riel
2016-08-19 18:00       ` Kees Cook
2016-08-19 10:31   ` Michal Hocko
2016-08-19 19:41 ` Linus Torvalds
2016-08-19 20:03   ` Kees Cook
2016-08-19 20:07     ` Linus Torvalds [this message]

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