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From: Oleg Nesterov <oleg@redhat.com>
To: Richard Guy Briggs <rgb@redhat.com>
Cc: John Johansen <john.johansen@canonical.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] apparmor: remove the "task" arg from may_change_ptraced_domain()
Date: Tue, 24 Sep 2013 18:44:42 +0200	[thread overview]
Message-ID: <20130924164442.GB4036@redhat.com> (raw)
In-Reply-To: <20130923215214.GV13968@madcap2.tricolour.ca>

On 09/23, Richard Guy Briggs wrote:
>
> On Mon, Sep 16, 2013 at 04:20:35PM +0200, Oleg Nesterov wrote:
> > Unless task == current ptrace_parent(task) is not safe even under
> > rcu_read_lock() and most of the current users are not right.
>
> Could you point to an explanation of this?

If this task exits before rcu_read_lock() ->parent can point to the
already freed/reused memory.

(in the long term we should probably clear
 ->parent/real_parent/group_leader/more in __unhash_process(), but
 lets not discuss this right now ;)

> (Did you send a patch to fix the selinux hook?)

No, sorry, I was sick. Will do.

> Acked-by: Richard Guy Briggs <rgb@redhat.com>

Thanks!

Oleg.


  reply	other threads:[~2013-09-24 16:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-16 14:20 [PATCH] apparmor: remove the "task" arg from may_change_ptraced_domain() Oleg Nesterov
2013-09-16 15:10 ` Oleg Nesterov
2013-09-16 17:01 ` John Johansen
2013-09-23 21:52 ` Richard Guy Briggs
2013-09-24 16:44   ` Oleg Nesterov [this message]
2013-09-26 13:25     ` Richard Guy Briggs
  -- strict thread matches above, loose matches on Subject: below --
2013-12-18 19:43 Richard Guy Briggs
2013-12-18 20:19 ` [PATCH] apparmor: remove the "task" arg from may_change_ptraced_domain() Oleg Nesterov
2013-12-20  4:36   ` Richard Guy Briggs
2013-12-20  6:22     ` John Johansen
2013-12-20 17:59     ` Oleg Nesterov

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