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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 8F3ACC35679 for ; Mon, 24 Feb 2020 07:32:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F37820637 for ; Mon, 24 Feb 2020 07:32:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="h5bFUu77" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727206AbgBXHcn (ORCPT ); Mon, 24 Feb 2020 02:32:43 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:57500 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725792AbgBXHcm (ORCPT ); Mon, 24 Feb 2020 02:32:42 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 01O7VL7i053525; Mon, 24 Feb 2020 07:32:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=ctgNwyDsGErJORzON8g3jp9u7VQvJRVglKKheMnzkkU=; b=h5bFUu77Tdpq7K6YcUFW/6O4hLpE73MsWFyh9w4MrdE0V4+wivoFHCxCP8oTouXgs3qA oOlexsdjkR9v5E/7QDKns/Ma8KiqUA8jnAtfbpwJmfjLWOIFdYT1+KL9qH8uD8J+1GpX PsNboxUAIqwRoBjNifdVjVhhQlsFsO07gYgWywQ5MOt9B3WHsIit5Ok4rdXba8gGCVLb 1YjHM4VscAqNv2BnyyPq60MTgaujJVZKMyKAIXOXAj1qMmKyqsC9FL43rSAO5M8GoWvc N2tQWhWrmDoXh66/Ih8FuPrYpB/k7y5lCRBCX5zPD1I4vEUNv0OXXEvPDMBBI5rk/D8s 2Q== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2yauqu5f6b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 24 Feb 2020 07:32:13 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 01O7SLXe162686; Mon, 24 Feb 2020 07:32:12 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3020.oracle.com with ESMTP id 2yby5anfs9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 24 Feb 2020 07:32:12 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 01O7W9o4007023; Mon, 24 Feb 2020 07:32:10 GMT Received: from kadam (/129.205.23.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 23 Feb 2020 23:32:09 -0800 Date: Mon, 24 Feb 2020 10:31:57 +0300 From: Dan Carpenter To: Christian Brauner Cc: Colin King , Christian Brauner , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Tejun Heo , kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH][next] clone3: fix an unsigned args.cgroup comparison to less than zero Message-ID: <20200224073157.GB3286@kadam> References: <20200222001513.43099-1-colin.king@canonical.com> <20200222121801.cu4dfnk4z5xd5uc2@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200222121801.cu4dfnk4z5xd5uc2@wittgenstein> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9540 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxscore=0 bulkscore=0 suspectscore=0 mlxlogscore=999 phishscore=0 adultscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002240065 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9540 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 bulkscore=0 clxscore=1011 malwarescore=0 impostorscore=0 adultscore=0 phishscore=0 priorityscore=1501 mlxlogscore=999 spamscore=0 mlxscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002240065 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 22, 2020 at 01:18:01PM +0100, Christian Brauner wrote: > On Sat, Feb 22, 2020 at 12:15:13AM +0000, Colin King wrote: > > From: Colin Ian King > > > > The less than zero comparison of args.cgroup is aways false because > > args.cgroup is a u64 and can never be less than zero. I believe the > > correct check is to cast args.cgroup to a s64 first to ensure an > > invalid value is not copied to kargs->cgroup. > > > > Addresses-Coverity: ("Unsigned compared against 0") > > Fixes: ef2c41cf38a7 ("clone3: allow spawning processes into cgroups") > > Signed-off-by: Colin Ian King > > Thanks, Colin. > Dan has reported this issue a few days prior on the janitors list so he > likely should get a > Reported-by: Dan Carpenter > too. Colin found it independently so no need for a Reported-by. > diff --git a/kernel/fork.c b/kernel/fork.c > index 2diff --git a/kernel/fork.c b/kernel/fork.c > index 2853e258fe1f..dca4dde3b5b2 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -2618,7 +2618,8 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, > !valid_signal(args.exit_signal))) > return -EINVAL; > > - if ((args.flags & CLONE_INTO_CGROUP) && args.cgroup < 0) > + if ((args.flags & CLONE_INTO_CGROUP) && > + (args.cgroup > INT_MAX || (s64)args.cgroup < 0)) If we're capping it at INT_MAX then the check for negative isn't required and static analysis tools know it's not so they might complain. regards, dan carpenter