From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751353AbZIBJpN (ORCPT ); Wed, 2 Sep 2009 05:45:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751083AbZIBJpB (ORCPT ); Wed, 2 Sep 2009 05:45:01 -0400 Received: from server1.wserver.cz ([82.113.45.157]:33035 "EHLO server1.wserver.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022AbZIBJpA (ORCPT ); Wed, 2 Sep 2009 05:45:00 -0400 From: Jiri Slaby To: oleg@redhat.com Cc: akpm@linux-foundation.org, mingo@redhat.com, linux-kernel@vger.kernel.org, Jiri Slaby Subject: [PATCH 2/2] core: allow setrlimit to non-current tasks Date: Wed, 2 Sep 2009 11:45:03 +0200 Message-Id: <1251884703-14523-2-git-send-email-jirislaby@gmail.com> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1251884703-14523-1-git-send-email-jirislaby@gmail.com> References: <1251884703-14523-1-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 | 25 ++++++++++++++++++------- 1 files changed, 18 insertions(+), 7 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index 919cebe..4a55bef 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1240,20 +1240,28 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, struct rlimit *new_rlim) { struct rlimit *old_rlim; + unsigned long flags; int retval; if (new_rlim->rlim_cur > new_rlim->rlim_max) return -EINVAL; + + if (lock_task_sighand(tsk, &flags) == NULL) + return -ESRCH; 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) { /* @@ -1281,9 +1289,12 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, if (new_rlim->rlim_cur == RLIM_INFINITY) goto out; - update_rlimit_cpu(tsk, new_rlim->rlim_cur); + __update_rlimit_cpu(tsk, new_rlim->rlim_cur); out: - return 0; + retval = 0; +unlock: + unlock_task_sighand(tsk, &flags); + return retval; } SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) -- 1.6.3.3