From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 437C6C43387 for ; Tue, 18 Dec 2018 17:34:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DE2F2133F for ; Tue, 18 Dec 2018 17:34:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727277AbeLRReD (ORCPT ); Tue, 18 Dec 2018 12:34:03 -0500 Received: from smtprelay0039.hostedemail.com ([216.40.44.39]:59432 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726839AbeLRReC (ORCPT ); Tue, 18 Dec 2018 12:34:02 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay05.hostedemail.com (Postfix) with ESMTP id 2527118028995; Tue, 18 Dec 2018 17:34:01 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: blow87_400871a9d6404 X-Filterd-Recvd-Size: 4506 Received: from XPS-9350.home (unknown [47.151.153.53]) (Authenticated sender: joe@perches.com) by omf05.hostedemail.com (Postfix) with ESMTPA; Tue, 18 Dec 2018 17:33:59 +0000 (UTC) Message-ID: <4db484684a6e9b096c7fdf57673fd208d1c4005a.camel@perches.com> Subject: Re: [PATCH] cifs: check kzalloc return From: Joe Perches To: Nicholas Mc Guire , Steve French Cc: linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org Date: Tue, 18 Dec 2018 09:33:58 -0800 In-Reply-To: <1545150439-26055-1-git-send-email-hofrat@osadl.org> References: <1545150439-26055-1-git-send-email-hofrat@osadl.org> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.1-1build1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2018-12-18 at 17:27 +0100, Nicholas Mc Guire wrote: > kzalloc can return NULL so a check is needed. While there is a > check for ret_buf there is no check for the allocation of > ret_buf->crfid.fid - this check is thus added. Both call-sites > of tconInfoAlloc() check for NULL return of tconInfoAlloc() > so returning NULL on failure of kzalloc() here seems appropriate. > As the kzalloc() is the only thing here that can fail it is > moved to the beginning so as not to initialize other resources > on failure of kzalloc. > > Signed-off-by: Nicholas Mc Guire > Fixes: 3d4ef9a15343 ("smb3: fix redundant opens on root") > --- > > Problem located with an experimental coccinelle script > > While at it make checkpatch happy by using *ret_buf->crfid.fid > rather than struct cifs_fid. > > Patch was compile tested with: x86_64_defconfig + CIFS=m > (with some unrelated smatch warnings and some pending cocci fixes) > > Patch is against v4.20-rc7 (localversion-next is next-20181218) [] > diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c [] > @@ -113,6 +113,13 @@ tconInfoAlloc(void) > struct cifs_tcon *ret_buf; > ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL); > if (ret_buf) { > + ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), > + GFP_KERNEL); > + if (!ret_buf->crfid.fid) { > + kfree(ret_buf); > + return NULL; > + } > + > atomic_inc(&tconInfoAllocCount); > ret_buf->tidStatus = CifsNew; > ++ret_buf->tc_count; > @@ -120,8 +127,6 @@ tconInfoAlloc(void) > INIT_LIST_HEAD(&ret_buf->tcon_list); > spin_lock_init(&ret_buf->open_file_lock); > mutex_init(&ret_buf->crfid.fid_mutex); > - ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid), > - GFP_KERNEL); > spin_lock_init(&ret_buf->stat_lock); > atomic_set(&ret_buf->num_local_opens, 0); > atomic_set(&ret_buf->num_remote_opens, 0); Perhaps use a more common style by returning early on the first possible failure too so the block can be unindented. Maybe as a separate cleanup patch. --- fs/cifs/misc.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 113980dba4d8..bee203055b30 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -111,21 +111,27 @@ struct cifs_tcon * tconInfoAlloc(void) { struct cifs_tcon *ret_buf; - ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL); - if (ret_buf) { - atomic_inc(&tconInfoAllocCount); - ret_buf->tidStatus = CifsNew; - ++ret_buf->tc_count; - INIT_LIST_HEAD(&ret_buf->openFileList); - INIT_LIST_HEAD(&ret_buf->tcon_list); - spin_lock_init(&ret_buf->open_file_lock); - mutex_init(&ret_buf->crfid.fid_mutex); - ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid), - GFP_KERNEL); - spin_lock_init(&ret_buf->stat_lock); - atomic_set(&ret_buf->num_local_opens, 0); - atomic_set(&ret_buf->num_remote_opens, 0); + + ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL); + if (!ret_buf) + return NULL; + ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL); + if (!ret_buf->crfid.fid) { + kfree(ret_buf); + return NULL; } + + atomic_inc(&tconInfoAllocCount); + ret_buf->tidStatus = CifsNew; + ++ret_buf->tc_count; + INIT_LIST_HEAD(&ret_buf->openFileList); + INIT_LIST_HEAD(&ret_buf->tcon_list); + spin_lock_init(&ret_buf->open_file_lock); + mutex_init(&ret_buf->crfid.fid_mutex); + spin_lock_init(&ret_buf->stat_lock); + atomic_set(&ret_buf->num_local_opens, 0); + atomic_set(&ret_buf->num_remote_opens, 0); + return ret_buf; }