Messages in this thread | | | Date | Thu, 20 Aug 2020 14:21:45 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] mm/migrate: Avoid possible unnecessary ptrace_may_access() call in kernel_move_pages() |
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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
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