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=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 E3E0AC169C4 for ; Tue, 29 Jan 2019 06:54:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B19582177E for ; Tue, 29 Jan 2019 06:54:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726181AbfA2Gyp (ORCPT ); Tue, 29 Jan 2019 01:54:45 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:54356 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725267AbfA2Gyp (ORCPT ); Tue, 29 Jan 2019 01:54:45 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id CC75514F0B3CF; Mon, 28 Jan 2019 22:54:44 -0800 (PST) Date: Mon, 28 Jan 2019 22:54:44 -0800 (PST) Message-Id: <20190128.225444.1929870241029842289.davem@davemloft.net> To: jasowang@redhat.com Cc: mst@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() From: David Miller In-Reply-To: <20190128070505.18335-1-jasowang@redhat.com> References: <20190128070505.18335-1-jasowang@redhat.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 28 Jan 2019 22:54:45 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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!