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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 39043C433FE for ; Fri, 11 Dec 2020 10:18:03 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 64ACD23C18 for ; Fri, 11 Dec 2020 10:18:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64ACD23C18 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37044 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1knfUv-0007pz-Av for qemu-devel@archiver.kernel.org; Fri, 11 Dec 2020 05:18:01 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:42726) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1knfTn-00071E-BK; Fri, 11 Dec 2020 05:16:53 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:2830) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1knfTi-0002yY-AX; Fri, 11 Dec 2020 05:16:51 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4Csmrq3T2RzkpS0; Fri, 11 Dec 2020 18:15:55 +0800 (CST) Received: from [10.174.187.138] (10.174.187.138) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.487.0; Fri, 11 Dec 2020 18:16:32 +0800 Message-ID: <5FD34700.3090001@huawei.com> Date: Fri, 11 Dec 2020 18:16:32 +0800 From: Alex Chen User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: "Dr. David Alan Gilbert" Subject: Re: [PATCH] virtiofsd: Fix potential NULL pointer dereference in virtio_send_msg() References: <20201210151426.89244-1-alex.chen@huawei.com> <20201210180010.GG3629@work-vm> In-Reply-To: <20201210180010.GG3629@work-vm> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.187.138] X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.190; envelope-from=alex.chen@huawei.com; helo=szxga04-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org, stefanha@redhat.com, zhang.zhanghailiang@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Dave, On 2020/12/11 2:00, Dr. David Alan Gilbert wrote: > * Alex Chen (alex.chen@huawei.com) wrote: >> The 'ch' will be NULL in the following stack: >> send_notify_iov()->fuse_send_msg()->virtio_send_msg(), >> so we should check 'ch' is valid before dereferencing it >> >> Reported-by: Euler Robot >> Signed-off-by: Alex Chen > > Please check, but I don't think we can currently hit this because > we never call send_notify_iov - it's currently called by > fuse_lowlevel_notify_inval_entry, inval_inode, and > fuse_lowlevel_notify_poll - > but I don't think those are called anywhere. > Thanks for your review. The send_notify_iov() is really not being called. > In that case, probably the best fix is to remove those until we > put notify back in. > OK, I will remove those temporarily useless code and send patch v2 to fix this problem. Thanks, Alex > Dave > >> --- >> tools/virtiofsd/fuse_virtio.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c >> index 623812c432..31b2187a15 100644 >> --- a/tools/virtiofsd/fuse_virtio.c >> +++ b/tools/virtiofsd/fuse_virtio.c >> @@ -205,6 +205,8 @@ static void copy_iov(struct iovec *src_iov, int src_count, >> int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, >> struct iovec *iov, int count) >> { >> + assert(ch); >> + >> FVRequest *req = container_of(ch, FVRequest, ch); >> struct fv_QueueInfo *qi = ch->qi; >> VuDev *dev = &se->virtio_dev->dev; >> -- >> 2.19.1 >>