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=-11.6 required=3.0 tests=BAYES_00,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,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 A11FAC433E1 for ; Mon, 13 Jul 2020 09:13:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E0B12067D for ; Mon, 13 Jul 2020 09:13:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="tzeG5ve5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729455AbgGMJNy (ORCPT ); Mon, 13 Jul 2020 05:13:54 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:54872 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726380AbgGMJNx (ORCPT ); Mon, 13 Jul 2020 05:13:53 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06D96nCd150599; Mon, 13 Jul 2020 09:13:40 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=XLvfUS4mbnV209WiCLIZkkPnGW6xeTZVH1WmfCUolWs=; b=tzeG5ve5TmruXBYeD9fe3P4ay+Nf1tkBPArT6w+89JT5hNRXDqSZU91+g15xPWrtafNt ZLTYImWy1OkIQ7w8fG/d39KP2quYoCC2Yvd1D/U+L+p9jYE2rPBwC9g7pa2ki+6mlrBP sQLkCQuENMsJAe01428Hub7ho75G6GAHVicrhf+BvvO+Ie4ELwQccA4lT2DsO8XSnmz2 gHNLgk0ksBwmu1ock23DP+QK3Iz3biOfIj56Jdmk49tcghTpeh9sTKkYgMorkr8Hy7MZ kFzTm6Yw2oiHwD7nauThznUSN4yjcgzy/scVg/eBdjKC15rpAUJKzkmJvvVY+ZP030mj Yw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 32762n5svv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 13 Jul 2020 09:13:40 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06D98X5X145817; Mon, 13 Jul 2020 09:13:40 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 327qbv8vbf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Jul 2020 09:13:40 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 06D9DcU1002442; Mon, 13 Jul 2020 09:13:38 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 13 Jul 2020 02:13:37 -0700 Date: Mon, 13 Jul 2020 12:13:29 +0300 From: Dan Carpenter To: Eric Biggers Cc: Peilin Ye , "David S . Miller" , Jakub Kicinski , Navid Emamdoost , Christophe JAILLET , Greg Kroah-Hartman , netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter() Message-ID: <20200713091329.GP2571@kadam> References: <20200712210300.200399-1-yepeilin.cs@gmail.com> <20200712213631.GA809@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200712213631.GA809@sol.localdomain> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9680 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 spamscore=0 mlxlogscore=999 bulkscore=0 malwarescore=0 mlxscore=0 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130071 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9680 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 spamscore=0 clxscore=1011 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 bulkscore=0 suspectscore=0 phishscore=0 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130071 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 12, 2020 at 02:36:31PM -0700, Eric Biggers wrote: > On Sun, Jul 12, 2020 at 05:03:00PM -0400, Peilin Ye wrote: > > qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count` > > equals to zero. Fix it by rejecting zero-length kzalloc() requests. > > > > This patch fixes the following syzbot bug: > > > > https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a > > > > Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com > > Signed-off-by: Peilin Ye > > --- > > net/qrtr/tun.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c > > index 15ce9b642b25..5465e94ba8e5 100644 > > --- a/net/qrtr/tun.c > > +++ b/net/qrtr/tun.c > > @@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from) > > ssize_t ret; > > void *kbuf; > > > > + if (!len) > > + return -EINVAL; > > + > > kbuf = kzalloc(len, GFP_KERNEL); > > if (!kbuf) > > return -ENOMEM; > > Wasn't this already fixed by: > > commit 8ff41cc21714704ef0158a546c3c4d07fae2c952 > Author: Dan Carpenter > Date: Tue Jun 30 14:46:15 2020 +0300 > > net: qrtr: Fix an out of bounds read qrtr_endpoint_post() Yep. If you're using kmalloc() you can allocate a zero byte buffer but you just can't access the array. for (i = 0; i < 0; i++) works. It's interesting because at the time, I wrote the patch I thought "len" probably couldn't be zero but I just checked it for completeness and readability. regards, dan carpenter 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=-11.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 34B0EC433DF for ; Mon, 13 Jul 2020 09:13:55 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E2C622067D for ; 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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=XLvfUS4mbnV209WiCLIZkkPnGW6xeTZVH1WmfCUolWs=; b=tzeG5ve5TmruXBYeD9fe3P4ay+Nf1tkBPArT6w+89JT5hNRXDqSZU91+g15xPWrtafNt ZLTYImWy1OkIQ7w8fG/d39KP2quYoCC2Yvd1D/U+L+p9jYE2rPBwC9g7pa2ki+6mlrBP sQLkCQuENMsJAe01428Hub7ho75G6GAHVicrhf+BvvO+Ie4ELwQccA4lT2DsO8XSnmz2 gHNLgk0ksBwmu1ock23DP+QK3Iz3biOfIj56Jdmk49tcghTpeh9sTKkYgMorkr8Hy7MZ kFzTm6Yw2oiHwD7nauThznUSN4yjcgzy/scVg/eBdjKC15rpAUJKzkmJvvVY+ZP030mj Yw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 32762n5svv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 13 Jul 2020 09:13:40 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06D98X5X145817; Mon, 13 Jul 2020 09:13:40 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 327qbv8vbf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Jul 2020 09:13:40 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 06D9DcU1002442; Mon, 13 Jul 2020 09:13:38 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 13 Jul 2020 02:13:37 -0700 Date: Mon, 13 Jul 2020 12:13:29 +0300 From: Dan Carpenter To: Eric Biggers Message-ID: <20200713091329.GP2571@kadam> References: <20200712210300.200399-1-yepeilin.cs@gmail.com> <20200712213631.GA809@sol.localdomain> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200712213631.GA809@sol.localdomain> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9680 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 spamscore=0 mlxlogscore=999 bulkscore=0 malwarescore=0 mlxscore=0 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130071 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9680 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 spamscore=0 clxscore=1011 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 bulkscore=0 suspectscore=0 phishscore=0 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130071 Cc: syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org, "David S . Miller" , Christophe JAILLET , netdev@vger.kernel.org, Jakub Kicinski , linux-kernel-mentees@lists.linuxfoundation.org, Peilin Ye , Navid Emamdoost Subject: Re: [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter() X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" On Sun, Jul 12, 2020 at 02:36:31PM -0700, Eric Biggers wrote: > On Sun, Jul 12, 2020 at 05:03:00PM -0400, Peilin Ye wrote: > > qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count` > > equals to zero. Fix it by rejecting zero-length kzalloc() requests. > > > > This patch fixes the following syzbot bug: > > > > https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a > > > > Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com > > Signed-off-by: Peilin Ye > > --- > > net/qrtr/tun.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c > > index 15ce9b642b25..5465e94ba8e5 100644 > > --- a/net/qrtr/tun.c > > +++ b/net/qrtr/tun.c > > @@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from) > > ssize_t ret; > > void *kbuf; > > > > + if (!len) > > + return -EINVAL; > > + > > kbuf = kzalloc(len, GFP_KERNEL); > > if (!kbuf) > > return -ENOMEM; > > Wasn't this already fixed by: > > commit 8ff41cc21714704ef0158a546c3c4d07fae2c952 > Author: Dan Carpenter > Date: Tue Jun 30 14:46:15 2020 +0300 > > net: qrtr: Fix an out of bounds read qrtr_endpoint_post() Yep. If you're using kmalloc() you can allocate a zero byte buffer but you just can't access the array. for (i = 0; i < 0; i++) works. It's interesting because at the time, I wrote the patch I thought "len" probably couldn't be zero but I just checked it for completeness and readability. regards, dan carpenter _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees