Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754769AbYLEGyO (ORCPT ); Fri, 5 Dec 2008 01:54:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751795AbYLEGx6 (ORCPT ); Fri, 5 Dec 2008 01:53:58 -0500 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:57460 "EHLO ecfrec.frec.bull.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751674AbYLEGx5 (ORCPT ); Fri, 5 Dec 2008 01:53:57 -0500 Message-Id: <20081205065210.495580470@bull.net> References: <20081205065053.966672287@bull.net> User-Agent: quilt/0.46-1 Date: Fri, 05 Dec 2008 07:50:54 +0100 From: Nadia.Derbey@bull.net To: containers@lists.osdl.org, oleg@redhat.com, xemul@openvz.org, sukadev@us.ibm.com Cc: ebiederm@xmission.com, linux-kernel@vger.kernel.org, Nadia.Derbey@bull.net Subject: [RFC][PATCH 1/1] Fix si_pid value when notifying about message arrival on POSIX mqueue Content-Disposition: inline; filename=mq_notify_fix_si_pid.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3374 Lines: 96 If a process registers for asynchronous notification on a POSIX message queue, it gets a signal and a siginfo_t structure when a message arrives on the message queue. The si_pid in the siginfo_t structure is set to the PID of the process that sent the message to the message queue. The principle is the following: . when mq_notify(SIGEV_SIGNAL) is called, the caller registers for notification when a msg arrives. The associated pid structure is stroed into inode_info->notify_owner. Let's call this process P1. . when mq_send() is called by say P2, P2 sends a signal to P1 to notify him about msg arrival. The way .si_pid is set today is not correct, since it doesn't take into account the fact that the process that is sending the message might not be in the same namespace as the notified one. This patch proposes to set si_pid to the sender's pid into the notify_owner namespace. Note: I've integrated in this patch a patch sent by Suka last week, that defines ns_of_pid() (see http://lkml.org/lkml/2008/11/25/460) Signed-off-by: Nadia Derbey --- include/linux/pid.h | 11 +++++++++++ ipc/mqueue.c | 12 +++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-) Index: linux-2.6.28-rc7/ipc/mqueue.c =================================================================== --- linux-2.6.28-rc7.orig/ipc/mqueue.c 2008-12-04 14:22:15.000000000 +0100 +++ linux-2.6.28-rc7/ipc/mqueue.c 2008-12-04 17:19:41.000000000 +0100 @@ -31,6 +31,7 @@ #include #include #include +#include #include #include "util.h" @@ -502,15 +503,24 @@ static void __do_notify(struct mqueue_in case SIGEV_SIGNAL: /* sends signal */ + { + struct pid_namespace *notify_ns; + sig_i.si_signo = info->notify.sigev_signo; sig_i.si_errno = 0; sig_i.si_code = SI_MESGQ; sig_i.si_value = info->notify.sigev_value; - sig_i.si_pid = task_tgid_vnr(current); + + rcu_read_lock(); + notify_ns = ns_of_pid(info->notify_owner); + sig_i.si_pid = task_tgid_nr_ns(current, notify_ns); + rcu_read_unlock(); + sig_i.si_uid = current->uid; kill_pid_info(info->notify.sigev_signo, &sig_i, info->notify_owner); + } break; case SIGEV_THREAD: set_cookie(info->notify_cookie, NOTIFY_WOKENUP); Index: linux-2.6.28-rc7/include/linux/pid.h =================================================================== --- linux-2.6.28-rc7.orig/include/linux/pid.h 2008-12-04 14:21:21.000000000 +0100 +++ linux-2.6.28-rc7/include/linux/pid.h 2008-12-04 14:57:56.000000000 +0100 @@ -122,6 +122,17 @@ int next_pidmap(struct pid_namespace *pi extern struct pid *alloc_pid(struct pid_namespace *ns); extern void free_pid(struct pid *pid); +/* ns_of_pid returns the pid namespace in which the specified + * pid was allocated. + */ +static inline struct pid_namespace *ns_of_pid(struct pid *pid) +{ + struct pid_namespace *ns = NULL; + if (pid) + ns = pid->numbers[pid->level].ns; + return ns; +} + /* * the helpers to get the pid's id seen from different namespaces * -- -- 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/