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From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org,
	Linux Containers <containers@lists.linux-foundation.org>,
	Christof Meerwald <cmeerw@cmeerw.org>
Subject: Re: [PATCH] signal: Avoid corrupting si_pid and si_uid in do_notify_parent
Date: Tue, 21 Apr 2020 11:28:47 +0200	[thread overview]
Message-ID: <20200421092846.GB6787@redhat.com> (raw)
In-Reply-To: <20200421083031.5wapruzncjkagvhf@wittgenstein>

On 04/21, Christian Brauner wrote:
>
> > -		__group_send_sig_info(sig, &info, tsk->parent);
> > +		__send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
>
> So below you switch to __send_signal() but set the "force" argument to
> to "false".

it must be false, the signal is generated from the parent's namespace or
its descendant

> Before that, if the signal was generated from another pid
> namespace and we fixed up si_pid and si_uid the "force" argument was set
> to "true",

before that the "force" argument could be falsely true by the same reason,
task_pid_nr_ns(tsk, tsk->parent) can return 0 because "tsk" no longer have
pids after __unhash_process().

Oleg.


  reply	other threads:[~2020-04-21  9:28 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-19 20:13 SIGCHLD signal sometimes sent with si_pid==0 (Linux 5.6.5) Christof Meerwald
2020-04-20 17:05 ` [PATCH] signal: Avoid corrupting si_pid and si_uid in do_notify_parent Eric W. Biederman
2020-04-21  8:30   ` Christian Brauner
2020-04-21  9:28     ` Oleg Nesterov [this message]
2020-04-21 10:21       ` Christian Brauner
2020-04-21 11:11         ` Oleg Nesterov
2020-04-21 11:26           ` Christian Brauner
2020-04-21 12:17             ` Oleg Nesterov
2020-04-21 12:59               ` Christian Brauner
2020-04-21 13:42                 ` Eric W. Biederman
2020-04-21 11:28           ` Oleg Nesterov
2020-04-21 11:38             ` Christian Brauner
2020-04-21 10:28     ` Christian Brauner
2020-04-21 14:57     ` Eric W. Biederman
2020-04-21 15:08       ` Christian Brauner
2020-04-21  9:04   ` Oleg Nesterov
2020-04-21 10:19     ` [PATCH] remove the no longer needed pid_alive() check in __task_pid_nr_ns() Oleg Nesterov
2020-04-21 10:50       ` Christian Brauner
2020-04-21 15:05       ` Eric W. Biederman
2020-04-24 18:05         ` Oleg Nesterov
2020-04-24 19:54           ` Eric W. Biederman
2020-04-21 14:59 ` SIGCHLD signal sometimes sent with si_pid==0 (Linux 5.6.5) Eric W. Biederman

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