From: Kees Cook <keescook@chromium.org>
To: linmiaohe <linmiaohe@huawei.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>
Subject: Re: [PATCH] mm/migrate: Avoid possible unnecessary ptrace_may_access() call in kernel_move_pages()
Date: Thu, 20 Aug 2020 14:21:45 -0700 [thread overview]
Message-ID: <202008201420.D9F0CB3E@keescook> (raw)
In-Reply-To: <9ce6209f41b64734b2cac748783aa441@huawei.com>
On Thu, Aug 20, 2020 at 02:18:21AM +0000, linmiaohe wrote:
> Kees Cook <keescook@chromium.org> wrote:
> >On Mon, Aug 17, 2020 at 07:59:33AM -0400, Miaohe Lin wrote:
> >> There is no need to check if this process has the right to modify the
> >> specified process when they are same.
> >>
> >> Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
> >> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> >
> >NAK, please don't do this -- the ptrace and security hooks already do these kinds of self-introspection checks, and I'd like to keep a central place to perform these kinds of checks.
> >
>
> Many thanks for your reply.
> We also avoid get_task_struct/ put_task_struct pair of atomic ops, rcu_lock, task_lock and so on this way.
>
> >Is there a specific problem you've encountered that this fixes?
> >
>
> I'am sorry but there's no specific problem. I do this mainly to skip the unnecessary ptrace and security hooks.
Cool. Let's keep this as-is so we continue to have centralized
instrumentation of these things in the LSM. :)
Thanks for your attention to performance!
--
Kees Cook
next prev parent reply other threads:[~2020-08-20 21:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 2:18 [PATCH] mm/migrate: Avoid possible unnecessary ptrace_may_access() call in kernel_move_pages() linmiaohe
2020-08-20 21:21 ` Kees Cook [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-08-18 2:25 linmiaohe
2020-08-17 11:59 Miaohe Lin
2020-08-17 12:32 ` Matthew Wilcox
2020-08-19 18:04 ` Kees Cook
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