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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 6EA07C43382 for ; Thu, 27 Sep 2018 23:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DDD82172F for ; Thu, 27 Sep 2018 23:37:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0DDD82172F 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 S1727370AbeI1F6f (ORCPT ); Fri, 28 Sep 2018 01:58:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57230 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725917AbeI1F6f (ORCPT ); Fri, 28 Sep 2018 01:58:35 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 00E7A308429C; Thu, 27 Sep 2018 23:37:49 +0000 (UTC) Received: from [10.72.12.26] (ovpn-12-26.pek2.redhat.com [10.72.12.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 616D46531E; Thu, 27 Sep 2018 23:37:40 +0000 (UTC) Subject: Re: [PATCH net V2] vhost-vsock: fix use after free To: "Michael S. Tsirkin" Cc: stefanha@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, sergei.shtylyov@cogentembedded.com References: <20180927122204.4188-1-jasowang@redhat.com> <20180927123539-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <588ed28b-7e4b-9dc8-92ce-d75692836c9e@redhat.com> Date: Fri, 28 Sep 2018 07:37:37 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180927123539-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 27 Sep 2018 23:37:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年09月28日 01:04, Michael S. Tsirkin wrote: > On Thu, Sep 27, 2018 at 08:22:04PM +0800, Jason Wang wrote: >> The access of vsock is not protected by vhost_vsock_lock. This may >> lead to use after free since vhost_vsock_dev_release() may free the >> pointer at the same time. >> >> Fix this by holding the lock during the access. >> >> Reported-by:syzbot+e3e074963495f92a89ed@syzkaller.appspotmail.com >> Fixes: 16320f363ae1 ("vhost-vsock: add pkt cancel capability") >> Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") >> Cc: Stefan Hajnoczi >> Signed-off-by: Jason Wang > Wow is that really the best we can do? For net/stable, probably yes. > A global lock on a data path > operation? It's already there, and the patch only increase the critical section. > Granted use after free is nasty but Stefan said he sees > a way to fix it using a per socket refcount. He's on vacation > until Oct 4 though ... > Stefan has acked the pacth, so I think it's ok? We can do optimization for -next on top. Thanks