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From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Manfred Spraul <manfred@colorfullife.com>,
	Markus Elfring <elfring@users.sourceforge.net>,
	Yoji <yoji.fujihar.min@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH -mm] ipc-mqueuec-change-__do_notify-to-bypass-check_kill_permission-fix
Date: Fri, 27 Mar 2020 20:56:43 +0100	[thread overview]
Message-ID: <20200327195643.GA9366@redhat.com> (raw)
In-Reply-To: <87v9mr1dlf.fsf@x220.int.ebiederm.org>

On 03/26, Eric W. Biederman wrote:
>
> > +			task = pid_task(info->notify_owner, PIDTYPE_PID);
>                                                             ^^^^^^^^^^^^
> Minor nit:  If we are doing the task lookup ourselves that can and
>             should be PIDTYPE_TGID.

I think this shouldn't make any difference, in particular because
do_mq_notify() does "notify_owner = task_tgid()" and we do not care
about exec.

But I agree, pid_task(PIDTYPE_TGID) looks better, thanks.


diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 63b164932ffd..9a44dcb04e13 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -801,7 +801,7 @@ static void __do_notify(struct mqueue_inode_info *info)
 			 * bypass check_kill_permission(). It is from kernel
 			 * but si_fromuser() can't know this.
 			 */
-			task = pid_task(info->notify_owner, PIDTYPE_PID);
+			task = pid_task(info->notify_owner, PIDTYPE_TGID);
 			if (task)
 				do_send_sig_info(info->notify.sigev_signo,
 						&sig_i, task, PIDTYPE_TGID);


      reply	other threads:[~2020-03-27 19:56 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22 11:09 [PATCH] ipc/mqueue.c: change __do_notify() to bypass check_kill_permission() Oleg Nesterov
2020-03-22 14:17 ` Eric W. Biederman
2020-03-22 14:59   ` Eric W. Biederman
2020-03-22 20:29   ` Oleg Nesterov
2020-03-23 16:47     ` Eric W. Biederman
2020-03-24  2:12       ` Andrew Morton
2020-03-24  2:57         ` Eric W. Biederman
2020-03-24 11:52           ` Oleg Nesterov
2020-03-24 20:08             ` Oleg Nesterov
2020-03-24 10:35       ` Oleg Nesterov
2020-03-24 20:09 ` [PATCH V2] " Oleg Nesterov
2020-03-26 12:54   ` Eric W. Biederman
2020-03-27 19:56     ` Oleg Nesterov [this message]

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