On Tue, Apr 13, 2021 at 4:34 PM Mathieu Desnoyers
<mathieu.desnoy...@efficios.com> wrote:
>
> ----- On Apr 13, 2021, at 3:36 AM, Eric Dumazet eric.duma...@gmail.com wrote:
>
> > From: Eric Dumazet <eduma...@google.com>
> >
> > After commit 8f2817701492 ("rseq: Use get_user/put_user rather
> > than __get_user/__put_user") we no longer need
> > an access_ok() call from __rseq_handle_notify_resume()
>
> While we are doing that, should we also remove the access_ok() check in
> rseq_syscall() ? It look like it can also be removed for the exact same
> reason outlined here.Yes, good idea. I was focusing in __rseq_handle_notify_resume() paths but rseq_syscall() can get the same. > Thanks, > > Mathieu > > > > > Signed-off-by: Eric Dumazet <eduma...@google.com> > > Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> > > Cc: Peter Zijlstra <pet...@infradead.org> > > Cc: "Paul E. McKenney" <paul...@kernel.org> > > Cc: Boqun Feng <boqun.f...@gmail.com> > > Cc: Arjun Roy <arjun...@google.com> > > Cc: Ingo Molnar <mi...@kernel.org> > > --- > > kernel/rseq.c | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/kernel/rseq.c b/kernel/rseq.c > > index > > d2689ccbb132c0fc8ec0924008771e5ee1ca855e..57344f9abb43905c7dd2b6081205ff508d963e1e > > 100644 > > --- a/kernel/rseq.c > > +++ b/kernel/rseq.c > > @@ -273,8 +273,6 @@ void __rseq_handle_notify_resume(struct ksignal *ksig, > > struct pt_regs *regs) > > > > if (unlikely(t->flags & PF_EXITING)) > > return; > > - if (unlikely(!access_ok(t->rseq, sizeof(*t->rseq)))) > > - goto error; > > ret = rseq_ip_fixup(regs); > > if (unlikely(ret < 0)) > > goto error; > > -- > > 2.31.1.295.g9ea45b61b8-goog > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com
