From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425074AbdEYSxG (ORCPT ); Thu, 25 May 2017 14:53:06 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:33662 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1036446AbdEYSvi (ORCPT ); Thu, 25 May 2017 14:51:38 -0400 From: Manfred Spraul To: mtk.manpages@gmail.com, Andrew Morton , Kees Cook Cc: LKML , 1vier1@web.de, Davidlohr Bueso , mingo@kernel.org, peterz@infradead.org, fabf@skynet.be, Manfred Spraul Subject: [PATCH 15/20] ipc/msg.c: Avoid ipc_rcu_putref for failed ipc_addid() Date: Thu, 25 May 2017 20:51:02 +0200 Message-Id: <20170525185107.12869-16-manfred@colorfullife.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170525185107.12869-1-manfred@colorfullife.com> References: <20170508222345.GA52073@beast> <20170525185107.12869-1-manfred@colorfullife.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Loosely based on a patch from Kees Cook : - id and retval can be merged - if ipc_addid() fails, then use call_rcu() directly. The difference is that call_rcu is used for failed ipc_addid() calls, to continue to guaranteed an rcu delay for security_msg_queue_free(). Signed-off-by: Manfred Spraul Cc: Kees Cook --- ipc/msg.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/ipc/msg.c b/ipc/msg.c index 10094a7..cd90bfd 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -132,7 +132,7 @@ static struct msg_queue *msg_alloc(void) static int newque(struct ipc_namespace *ns, struct ipc_params *params) { struct msg_queue *msq; - int id, retval; + int retval; key_t key = params->key; int msgflg = params->flg; @@ -160,10 +160,10 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params) INIT_LIST_HEAD(&msq->q_senders); /* ipc_addid() locks msq upon success. */ - id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); - if (id < 0) { - ipc_rcu_putref(&msq->q_perm, msg_rcu_free); - return id; + retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); + if (retval < 0) { + call_rcu(&msq->q_perm.rcu, msg_rcu_free); + return retval; } ipc_unlock_object(&msq->q_perm); -- 2.9.3