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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 96922C282DD for ; Fri, 10 Jan 2020 15:49:48 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6318120721 for ; Fri, 10 Jan 2020 15:49:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="J/s036gx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6318120721 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48266 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ipwXj-0004T3-7m for qemu-devel@archiver.kernel.org; Fri, 10 Jan 2020 10:49:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35497) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ipwSJ-00076M-BS for qemu-devel@nongnu.org; Fri, 10 Jan 2020 10:44:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ipwSI-0002JP-2J for qemu-devel@nongnu.org; Fri, 10 Jan 2020 10:44:11 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:34694 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ipwSH-0002Hf-SF for qemu-devel@nongnu.org; Fri, 10 Jan 2020 10:44:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578671049; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4x4BxsET7gPo2+t+isJ34uT7paifFc8+d+aqpS8J6hg=; b=J/s036gxJallhZzwB++1fpuWtaq0ffN0YWif+pggt+UI7rZ8T34QuuuGOBP5uJEgVStJ6o f5RiElQC02aWQ0SDPEa375G3hiCXtAyxHdDWVApZZs5OLOFg8SYjuxbV17DSZ8B+NgV4/4 lbuTTVdTs8EiEjXaxPKNlwgNTLDP9NI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-66-QFBUWIJ3PTuELeWXnmMvQQ-1; Fri, 10 Jan 2020 10:44:06 -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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id DB5368024D2 for ; Fri, 10 Jan 2020 15:44:05 +0000 (UTC) Received: from work-vm (unknown [10.36.118.36]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6F7AA10016E8; Fri, 10 Jan 2020 15:44:02 +0000 (UTC) Date: Fri, 10 Jan 2020 15:43:59 +0000 From: "Dr. David Alan Gilbert" To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Subject: Re: [PATCH 062/104] virtiofsd: Handle hard reboot Message-ID: <20200110154359.GI3901@work-vm> References: <20191212163904.159893-1-dgilbert@redhat.com> <20191212163904.159893-63-dgilbert@redhat.com> <20200107111437.GF3368802@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200107111437.GF3368802@redhat.com> User-Agent: Mutt/1.13.0 (2019-11-30) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: QFBUWIJ3PTuELeWXnmMvQQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Daniel P. Berrang=E9 (berrange@redhat.com) wrote: > On Thu, Dec 12, 2019 at 04:38:22PM +0000, Dr. David Alan Gilbert (git) wr= ote: > > From: "Dr. David Alan Gilbert" > >=20 > > Handle a > > mount > > hard reboot (without unmount) > > mount > >=20 > > we get another 'init' which FUSE doesn't normally expect. > >=20 > > Signed-off-by: Dr. David Alan Gilbert > > --- > > tools/virtiofsd/fuse_lowlevel.c | 16 +++++++++++++++- > > 1 file changed, 15 insertions(+), 1 deletion(-) > >=20 > > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_low= level.c > > index 2d1d1a2e59..45125ef66a 100644 > > --- a/tools/virtiofsd/fuse_lowlevel.c > > +++ b/tools/virtiofsd/fuse_lowlevel.c > > @@ -2436,7 +2436,21 @@ void fuse_session_process_buf_int(struct fuse_se= ssion *se, > > goto reply_err; > > } > > } else if (in->opcode =3D=3D FUSE_INIT || in->opcode =3D=3D CUSE_I= NIT) { > > - goto reply_err; > > + if (fuse_lowlevel_is_virtio(se)) { > > + /* > > + * TODO: This is after a hard reboot typically, we need to= do > > + * a destroy, but we can't reply to this request yet so > > + * we can't use do_destroy > > + */ > > + fuse_log(FUSE_LOG_DEBUG, "%s: reinit\n", __func__); > > + se->got_destroy =3D 1; > > + se->got_init =3D 0; > > + if (se->op.destroy) { > > + se->op.destroy(se->userdata); > > + } > > + } else { > > + goto reply_err; > > + } >=20 > In doing this, is there any danger we're exposed to from a malicious > guest which does >=20 > mount > mount >=20 > without a reboot in between ? I don't think so - or at least not from the daemon side of things; if it were to do that (and get two FUSE_INIT's) then the state of it's first mount would be rather messed up; but the only thing to suffer would be the kernel doing that odd re-init, so I don't think the maliciousness should break anyone else. > I'm thinking not so if its ok, then >=20 > Reviewed-by: Daniel P. Berrang=E9 Thanks. >=20 > Regards, > Daniel > --=20 > |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| > |: https://libvirt.org -o- https://fstop138.berrange.c= om :| > |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK