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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 8C26CC04EB8 for ; Fri, 30 Nov 2018 13:44:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59F962145D for ; Fri, 30 Nov 2018 13:44:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59F962145D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727196AbeLAAxo (ORCPT ); Fri, 30 Nov 2018 19:53:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36182 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726070AbeLAAxo (ORCPT ); Fri, 30 Nov 2018 19:53:44 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 69C543164669; Fri, 30 Nov 2018 13:44:22 +0000 (UTC) Received: from redhat.com (ovpn-120-67.rdu2.redhat.com [10.10.120.67]) by smtp.corp.redhat.com (Postfix) with SMTP id CECBE1057075; Fri, 30 Nov 2018 13:44:16 +0000 (UTC) Date: Fri, 30 Nov 2018 08:44:16 -0500 From: "Michael S. Tsirkin" To: Linus Torvalds Cc: Kees Cook , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, Linux Kernel Mailing List , Andrew Morton , bijan.mottahedeh@oracle.com, gedwards@ddn.com, joe@perches.com, lenaic@lhuard.fr, liang.z.li@intel.com, mhocko@kernel.org, mhocko@suse.com, stefanha@redhat.com, wei.w.wang@intel.com Subject: Re: [PULL] vhost: cleanups and fixes Message-ID: <20181130084227-mutt-send-email-mst@kernel.org> References: <20181101171938-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Fri, 30 Nov 2018 13:44:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 01, 2018 at 04:06:19PM -0700, Linus Torvalds wrote: > On Thu, Nov 1, 2018 at 4:00 PM Kees Cook wrote: > > > > + memset(&rsp, 0, sizeof(rsp)); > > + rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED; > > + resp = vq->iov[out].iov_base; > > + ret = __copy_to_user(resp, &rsp, sizeof(rsp)); > > > > Is it actually safe to trust that iov_base has passed an earlier > > access_ok() check here? Why not just use copy_to_user() instead? > > Good point. > > We really should have removed those double-underscore things ages ago. > > Also, apart from the address, what about the size? Wouldn't it be > better to use copy_to_iter() rather than implement it badly by hand? > > Linus Bijan can you respond please? Are you going to look into this and convert code to copy_to_iter? I don't think we should release Linux like this, so if you don't have the time I'd rather revert for now and you can look into reposting for the next release. Thanks, -- MST