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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98D32CE7AF8 for ; Thu, 28 Sep 2023 04:06:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230149AbjI1EGJ (ORCPT ); Thu, 28 Sep 2023 00:06:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229453AbjI1EGI (ORCPT ); Thu, 28 Sep 2023 00:06:08 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9714510A for ; Wed, 27 Sep 2023 21:05:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695873922; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZrLjkHF0/HwoOXQ2UetFuy9QaHx8cXgataUvrO0ObDQ=; b=SRIkcUZ3sLmLgGjlfkYqbTTGqGBq6ub9qudt/0+6Rg5eN4kZwIfU+U+x4ODyO/BTPmXCMt jVBgMVTA/Z98fR3pfXqwy1fqiSHemjabro7rDxbxsHCVXXxGuNkeZ2cHx5MWFcYF/glOjS FKCV1gHo2h0ZNUgSJTnpZ28zz031+gU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-657-T1n3Zf0xOJ-gjUrloG85LQ-1; Thu, 28 Sep 2023 00:05:17 -0400 X-MC-Unique: T1n3Zf0xOJ-gjUrloG85LQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2F85E85A5BD; Thu, 28 Sep 2023 04:05:17 +0000 (UTC) Received: from fedora (unknown [10.72.120.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E6A03C15BB8; Thu, 28 Sep 2023 04:05:10 +0000 (UTC) Date: Thu, 28 Sep 2023 12:05:05 +0800 From: Ming Lei To: linan666@huaweicloud.com Cc: josef@toxicpanda.com, axboe@kernel.dk, linux-block@vger.kernel.org, nbd@other.debian.org, linux-kernel@vger.kernel.org, linan122@huawei.com, yukuai3@huawei.com, yi.zhang@huawei.com, houtao1@huawei.com, yangerkun@huawei.com, ming.lei@redhat.com Subject: Re: [PATCH] nbd: pass nbd_sock to nbd_read_reply() instead of index Message-ID: References: <20230911023308.3467802-1-linan666@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230911023308.3467802-1-linan666@huaweicloud.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 11, 2023 at 10:33:08AM +0800, linan666@huaweicloud.com wrote: > From: Li Nan > > If a socket is processing ioctl 'NBD_SET_SOCK', config->socks might be > krealloc in nbd_add_socket(), and a garbage request is received now, a UAF > may occurs. > > T1 > nbd_ioctl > __nbd_ioctl > nbd_add_socket > blk_mq_freeze_queue > T2 > recv_work > nbd_read_reply > sock_xmit > krealloc config->socks > def config->socks > > Pass nbd_sock to nbd_read_reply(). And introduce a new function > sock_xmit_recv(), which differs from sock_xmit only in the way it get > socket. > I am wondering why not grab queue usage counter before calling nbd_read_reply() for avoiding such issue, something like the following change: diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index df1cd0f718b8..09215b605b12 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -837,9 +837,6 @@ static void recv_work(struct work_struct *work) while (1) { struct nbd_reply reply; - if (nbd_read_reply(nbd, args->index, &reply)) - break; - /* * Grab .q_usage_counter so request pool won't go away, then no * request use-after-free is possible during nbd_handle_reply(). @@ -852,6 +849,9 @@ static void recv_work(struct work_struct *work) break; } + if (nbd_read_reply(nbd, args->index, &reply)) + break; + cmd = nbd_handle_reply(nbd, args->index, &reply); if (IS_ERR(cmd)) { percpu_ref_put(&q->q_usage_counter); Thanks, Ming