From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754046AbZHaS4g (ORCPT ); Mon, 31 Aug 2009 14:56:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753466AbZHaS4N (ORCPT ); Mon, 31 Aug 2009 14:56:13 -0400 Received: from server1.wserver.cz ([82.113.45.157]:36629 "EHLO server1.wserver.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753708AbZHaS4J (ORCPT ); Mon, 31 Aug 2009 14:56:09 -0400 From: Jiri Slaby To: akpm@linux-foundation.org Cc: mingo@redhat.com, oleg@redhat.com, linux-kernel@vger.kernel.org, Jiri Slaby Subject: [PATCH 5/6] core: allow setrlimit to non-current tasks Date: Mon, 31 Aug 2009 20:56:13 +0200 Message-Id: <1251744974-29398-5-git-send-email-jirislaby@gmail.com> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1251744974-29398-1-git-send-email-jirislaby@gmail.com> References: <1251744974-29398-1-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 signal and sighand non-null. Do all the signal processing under that lock still held. Signed-off-by: Jiri Slaby Cc: Oleg Nesterov --- kernel/sys.c | 26 ++++++++++++++++++++------ 1 files changed, 20 insertions(+), 6 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index 919cebe..777a152 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1244,16 +1244,27 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, if (new_rlim->rlim_cur > new_rlim->rlim_max) return -EINVAL; + + /* protect tsk->signal and tsk->sighand from disappearing */ + read_lock_irq(&tasklist_lock); + if (!tsk->signal || !tsk->sighand) { + retval = -ESRCH; + goto unlock; + } old_rlim = tsk->signal->rlim + resource; if ((new_rlim->rlim_max > old_rlim->rlim_max) && - !capable(CAP_SYS_RESOURCE)) - return -EPERM; - if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open) - return -EPERM; + !capable(CAP_SYS_RESOURCE)) { + retval = -EPERM; + goto unlock; + } + if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open) { + retval = -EPERM; + goto unlock; + } retval = security_task_setrlimit(tsk, resource, new_rlim); if (retval) - return retval; + goto unlock; if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { /* @@ -1283,7 +1294,10 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, update_rlimit_cpu(tsk, new_rlim->rlim_cur); out: - return 0; + retval = 0; +unlock: + read_unlock_irq(&tasklist_lock); + return retval; } SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) -- 1.6.3.3