From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754041AbZJQVWj (ORCPT ); Sat, 17 Oct 2009 17:22:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753876AbZJQVWi (ORCPT ); Sat, 17 Oct 2009 17:22:38 -0400 Received: from server1.wserver.cz ([82.113.45.157]:60880 "EHLO server1.wserver.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753884AbZJQVVX (ORCPT ); Sat, 17 Oct 2009 17:21:23 -0400 From: Jiri Slaby To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, Jiri Slaby , Oleg Nesterov Subject: [PATCH -repost 6/8] core: allow setrlimit to non-current tasks Date: Sat, 17 Oct 2009 23:21:20 +0200 Message-Id: <1255814482-13994-6-git-send-email-jirislaby@gmail.com> X-Mailer: git-send-email 1.6.4.2 In-Reply-To: <1255814482-13994-1-git-send-email-jirislaby@gmail.com> References: <1255814482-13994-1-git-send-email-jirislaby@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add locking to allow setrlimit accept task parameter other than current. Namely, lock tasklist_lock for read and check whether the task structure has sighand non-null. Do all the signal processing under that lock still held. Signed-off-by: Jiri Slaby Cc: Oleg Nesterov --- kernel/sys.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index 2dc84b9..5bb80d6 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1238,6 +1238,7 @@ SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource, #endif +/* make sure you are allowed to change @tsk limits before calling this */ int setrlimit(struct task_struct *tsk, unsigned int resource, struct rlimit *new_rlim) { @@ -1249,9 +1250,16 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open) return -EPERM; + /* protect tsk->signal and tsk->sighand from disappearing */ + read_lock(&tasklist_lock); + if (!tsk->sighand) { + retval = -ESRCH; + goto out; + } + retval = security_task_setrlimit(tsk, resource, new_rlim); if (retval) - return retval; + goto out; if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { /* @@ -1286,6 +1294,7 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, update_rlimit_cpu(tsk, new_rlim->rlim_cur); out: + read_unlock(&tasklist_lock); return retval; } -- 1.6.4.2