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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 3013EC169C4 for ; Tue, 29 Jan 2019 22:54:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED5FA20882 for ; Tue, 29 Jan 2019 22:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729744AbfA2Wyv (ORCPT ); Tue, 29 Jan 2019 17:54:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35966 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727488AbfA2Wyu (ORCPT ); Tue, 29 Jan 2019 17:54:50 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7F0687AE8B; Tue, 29 Jan 2019 22:54:50 +0000 (UTC) Received: from redhat.com (ovpn-123-79.rdu2.redhat.com [10.10.123.79]) by smtp.corp.redhat.com (Postfix) with SMTP id 2518D5D96F; Tue, 29 Jan 2019 22:54:44 +0000 (UTC) Date: Tue, 29 Jan 2019 17:54:44 -0500 From: "Michael S. Tsirkin" To: David Miller Cc: jasowang@redhat.com, stefanha@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] vhost: fix OOB in get_rx_bufs() Message-ID: <20190129175145-mutt-send-email-mst@kernel.org> References: <20190128070505.18335-1-jasowang@redhat.com> <20190128.225444.1929870241029842289.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190128.225444.1929870241029842289.davem@davemloft.net> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 29 Jan 2019 22:54:50 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 28, 2019 at 10:54:44PM -0800, David Miller wrote: > From: Jason Wang > Date: Mon, 28 Jan 2019 15:05:05 +0800 > > > After batched used ring updating was introduced in commit e2b3b35eb989 > > ("vhost_net: batch used ring update in rx"). We tend to batch heads in > > vq->heads for more than one packet. But the quota passed to > > get_rx_bufs() was not correctly limited, which can result a OOB write > > in vq->heads. > > > > headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, > > vhost_len, &in, vq_log, &log, > > likely(mergeable) ? UIO_MAXIOV : 1); > > > > UIO_MAXIOV was still used which is wrong since we could have batched > > used in vq->heads, this will cause OOB if the next buffer needs more > > than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've > > batched 64 (VHOST_NET_BATCH) heads: > ... > > Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for > > vhost-net. This is done through set the limitation through > > vhost_dev_init(), then set_owner can allocate the number of iov in a > > per device manner. > > > > This fixes CVE-2018-16880. > > > > Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx") > > Signed-off-by: Jason Wang > > Applied and queued up for -stable, thanks! Wow it seems we are down to hours round time post to queue. It would be hard to keep up that rate generally. However, I am guessing this was already in downstreams, and it's a CVE, so I guess it's a no brainer and review wasn't really necessary - was that the idea? Just checking. -- MST