Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754901AbXKZPBM (ORCPT ); Mon, 26 Nov 2007 10:01:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753188AbXKZPA6 (ORCPT ); Mon, 26 Nov 2007 10:00:58 -0500 Received: from sacred.ru ([62.205.161.221]:46260 "EHLO sacred.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbXKZPA5 (ORCPT ); Mon, 26 Nov 2007 10:00:57 -0500 Message-ID: <474ADF94.5050500@openvz.org> Date: Mon, 26 Nov 2007 18:00:36 +0300 From: Pavel Emelyanov User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Oleg Nesterov CC: Andrew Morton , "Eric W. Biederman" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] fix setsid() for sub-namespace /sbin/init References: <20071126142553.GA16525@tv-sign.ru> In-Reply-To: <20071126142553.GA16525@tv-sign.ru> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-3.0 (sacred.ru [62.205.161.221]); Mon, 26 Nov 2007 18:00:36 +0300 (MSK) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2500 Lines: 68 Oleg Nesterov wrote: > sys_setsid() still deals with pid_t's from the global namespace. This means > that the "session > 1" check can't help for sub-namespace init, setsid() can't > succeed because copy_process(CLONE_NEWPID) populates PIDTYPE_PGID/SID links. > > Remove the usage of task_struct->pid and convert the code to use "struct pid". > This also simplifies and speedups the code, saves one find_pid(). > > Signed-off-by: Oleg Nesterov Acked-by: Pavel Emelyanov > --- PT/kernel/sys.c~1_setsid 2007-11-26 15:52:15.000000000 +0300 > +++ PT/kernel/sys.c 2007-11-26 16:10:43.000000000 +0300 > @@ -1045,35 +1045,33 @@ asmlinkage long sys_getsid(pid_t pid) > asmlinkage long sys_setsid(void) > { > struct task_struct *group_leader = current->group_leader; > - pid_t session; > + struct pid *sid = task_pid(group_leader); > + pid_t session = pid_vnr(sid); > int err = -EPERM; > > write_lock_irq(&tasklist_lock); > - > /* Fail if I am already a session leader */ > if (group_leader->signal->leader) > goto out; > > - session = group_leader->pid; > - /* Fail if a process group id already exists that equals the > - * proposed session id. > + /* Fail if a process group id already exists that equals the proposed > + * session id. > * > - * Don't check if session id == 1 because kernel threads use this > - * session id and so the check will always fail and make it so > - * init cannot successfully call setsid. > + * Don't check if session == 1 because kernel threads and CLONE_NEWPID > + * tasks use this session id and so the check will always fail and make > + * it so init cannot successfully call setsid. > */ > - if (session > 1 && find_task_by_pid_type_ns(PIDTYPE_PGID, > - session, &init_pid_ns)) > + if (session != 1 && pid_task(sid, PIDTYPE_PGID)) > goto out; > > group_leader->signal->leader = 1; > - __set_special_pids(session, session); > + __set_special_pids(pid_nr(sid), pid_nr(sid)); > > spin_lock(&group_leader->sighand->siglock); > group_leader->signal->tty = NULL; > spin_unlock(&group_leader->sighand->siglock); > > - err = task_pgrp_vnr(group_leader); > + err = session; > out: > write_unlock_irq(&tasklist_lock); > return err; > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/