From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756482AbZAGHyM (ORCPT ); Wed, 7 Jan 2009 02:54:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752316AbZAGHxy (ORCPT ); Wed, 7 Jan 2009 02:53:54 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:33174 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752268AbZAGHxx (ORCPT ); Wed, 7 Jan 2009 02:53:53 -0500 Date: Tue, 6 Jan 2009 23:51:23 -0800 From: Sukadev Bhattiprolu To: oleg@redhat.com, ebiederm@xmission.com, roland@redhat.com, bastian@waldi.eu.org Cc: containers@lists.osdl.org, linux-kernel@vger.kernel.org, xemul@openvz.org Subject: [PATCH 4/7][v6] Define siginfo_from_ancestor_ns() Message-ID: <20090107075123.GD27985@us.ibm.com> References: <20090107074558.GA27881@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090107074558.GA27881@us.ibm.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sukadev Bhattiprolu Date: Wed, 24 Dec 2008 13:46:02 -0800 Subject: [PATCH 4/7][v6] Define siginfo_from_ancestor_ns() Determine if sender of a signal is from an ancestor namespace. This function will be used in a follow-on patch. This is based on discussions on the patch from Oleg Nesterov and me http://lkml.org/lkml/2008/11/25/462. Changelog[v6]: - (Oleg Nesterov) Simplify/correct comments - (Oleg Nesterov) Remove 'ns == NULL' check since task_active_pid_ns() will return a valid ns for the target. - (Roland Mcgrath) Remove incorrect SI_ASYNCIO check in siginfo_from_user(). Changelog[v5]: - (Oleg Nesterov) Put siginfo_from_ancestor_ns() back under CONFIG_PID_NS. - (Oleg Nesterov) Remove the warning in rt_sigqueueinfo(). Changelog[v4]: - siginfo_from_ancestor_ns() is fairly clean and it does not need to be under CONFIG_PID_NS. Only siginfo_from_user() needs to be. - Warn if rt_sigqueueinfo() uses SI_ASYNCIO. - Added a check for pid-ns of receiver being NULL (in case it is exiting). Signed-off-by: Sukadev Bhattiprolu --- kernel/signal.c | 37 +++++++++++++++++++++++++++++++++++++ 1 files changed, 37 insertions(+), 0 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index bb3b6f5..d0dfa0d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -820,6 +820,43 @@ static inline int legacy_queue(struct sigpending *signals, int sig) { return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); } +/* + * Return 1 if this signal originated directly from a user process (i.e via + * kill(), tkill(), sigqueue()). Return 0 otherwise. + */ +#ifdef CONFIG_PID_NS +static inline int siginfo_from_user(siginfo_t *info) +{ + if (!is_si_special(info) && SI_FROMUSER(info)) + return 1; + + return 0; +} + +static inline int siginfo_from_ancestor_ns(struct task_struct *t, + siginfo_t *info) +{ + /* + * If we do not have a pid in the receiver's namespace, + * we must be from an ancestor namespace. + */ + if (siginfo_from_user(info) && + task_pid_nr_ns(current, task_active_pid_ns(t)) <= 0) { + return 1; + } + + return 0; +} + +#else + +static inline int siginfo_from_ancestor_ns(struct task_struct *t, + siginfo_t *info) +{ + return 0; +} + +#endif static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, int group, int from_ancestor_ns) -- 1.5.2.5