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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 04B61C5ACAE for ; Wed, 11 Sep 2019 13:52:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA2F3206CD for ; Wed, 11 Sep 2019 13:52:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728067AbfIKNwc (ORCPT ); Wed, 11 Sep 2019 09:52:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53114 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727576AbfIKNwc (ORCPT ); Wed, 11 Sep 2019 09:52:32 -0400 Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 67907C059B7A for ; Wed, 11 Sep 2019 13:52:31 +0000 (UTC) Received: by mail-qt1-f197.google.com with SMTP id f19so23865257qtq.1 for ; Wed, 11 Sep 2019 06:52:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=bTpTDYaW4L1Gk4pQTaJgOsQGofG8+keatPi5K+boUSM=; b=kD21bfRSlq36d9s67ZMM/4oF+Qf3bHWDn29FeDhx5ifoLDbx+F9Jmbyp16R4FuczZP tNOkPGeILXsHa0F5IPfEVO8WG7fusnEOW7zKmQSfuL/b8OE8tud3cBN7YofybSzlNlC9 LGVhf4NbjMPYAuXNYAwnQiSyXqpxn+tc5Ke+oV0RR9H/CqLDUOxX1AxpPwaF6EWsyWV/ Hr9cJfH8O7qGnkPuE+f9KDxdM2D9Jbm/M5RR/ObopXlck13jM4aJV7ZuQEFhlL1IOe2X QNXZ8rmAOpLER+Z1GBBeb/QymwjOcxCxwjLIbZgtOMd4FmKfIW3fINVmUNKeUF6G3zAj wHSg== X-Gm-Message-State: APjAAAU5jl1vFQBDNtn0QV0wic8AXGc697IR/UblWdg4YKRETZL9TeuG 1dXImkHVKpLQ5/tqpAEBTNaYjUnS5kTCitkZjR86DjzXBqqi0fbwRsfLusXZKWNatw/5fScEMT2 p4paDelDCjrHl X-Received: by 2002:a37:4651:: with SMTP id t78mr35308378qka.259.1568209950747; Wed, 11 Sep 2019 06:52:30 -0700 (PDT) X-Google-Smtp-Source: APXvYqzAArEKuceihQtc6r95FHhQta9AhTzn+LrxDRMztlrzqQf2WbTHO7axIccFjavXyHt6DHiEWw== X-Received: by 2002:a37:4651:: with SMTP id t78mr35308358qka.259.1568209950581; Wed, 11 Sep 2019 06:52:30 -0700 (PDT) Received: from redhat.com ([80.74.107.118]) by smtp.gmail.com with ESMTPSA id n62sm9969475qkd.124.2019.09.11.06.52.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Sep 2019 06:52:29 -0700 (PDT) Date: Wed, 11 Sep 2019 09:52:25 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, security@kernel.org Subject: Re: [PATCH v2] vhost: block speculation of translated descriptors Message-ID: <20190911095147-mutt-send-email-mst@kernel.org> References: <20190911120908.28410-1-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190911120908.28410-1-mst@redhat.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Sep 11, 2019 at 08:10:00AM -0400, Michael S. Tsirkin wrote: > iovec addresses coming from vhost are assumed to be > pre-validated, but in fact can be speculated to a value > out of range. > > Userspace address are later validated with array_index_nospec so we can > be sure kernel info does not leak through these addresses, but vhost > must also not leak userspace info outside the allowed memory table to > guests. > > Following the defence in depth principle, make sure > the address is not validated out of node range. > > Signed-off-by: Michael S. Tsirkin > Acked-by: Jason Wang > Tested-by: Jason Wang > --- Cc: security@kernel.org Pls advise on whether you'd like me to merge this directly, Cc stable, or handle it in some other way. > changes from v1: fix build on 32 bit > > drivers/vhost/vhost.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 5dc174ac8cac..34ea219936e3 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2071,8 +2071,10 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, > _iov = iov + ret; > size = node->size - addr + node->start; > _iov->iov_len = min((u64)len - s, size); > - _iov->iov_base = (void __user *)(unsigned long) > - (node->userspace_addr + addr - node->start); > + _iov->iov_base = (void __user *) > + ((unsigned long)node->userspace_addr + > + array_index_nospec((unsigned long)(addr - node->start), > + node->size)); > s += size; > addr += size; > ++ret; > -- > MST