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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 F30F4C2D0DB for ; Wed, 22 Jan 2020 14:27:29 +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 BE148217F4 for ; Wed, 22 Jan 2020 14:27:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (4096-bit key) header.d=crudebyte.com header.i=@crudebyte.com header.b="nKyRpG1M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE148217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=crudebyte.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42964 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuGye-000552-L7 for qemu-devel@archiver.kernel.org; Wed, 22 Jan 2020 09:27:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59704) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuGxW-0003ka-Tg for qemu-devel@nongnu.org; Wed, 22 Jan 2020 09:26:20 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iuGxV-0001dJ-NL for qemu-devel@nongnu.org; Wed, 22 Jan 2020 09:26:18 -0500 Received: from kylie.crudebyte.com ([5.189.157.229]:54381) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iuGxV-0001Zx-6i for qemu-devel@nongnu.org; Wed, 22 Jan 2020 09:26:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=o3fpBiCs+ILBZnbU9Cda+t7v8Q0Y9XmKKPCJRGHxbAI=; b=nKyRpG1MrIRSH+Lx5+VzkyK7QR heW9VIxOhrC/bQTFkB1saDLhJ4k3dokG58C4S/S4s+lSLk3CP7dMe8hHtPhSpuYr+xcHWaUIiJDru a5ccAN4QmpuoP7UoV/S1Lxq6H0GV/HuxMyzriKMRXTAhlHsnJ3gNA6Am/Ul8I1woxKt6Su3Hfpp4U KlhPu4C2i5xH70NdihcHcVhz51Nt+Rlf2oQejIbt4Z3dD5Bao9DwDZGymYa/djKH6KWX7Jc675ARQ ippg53H85KYYz+R8k+Gg0Qxstg8gKqN2jQcqvAV2Xuu1uEZImnFug6hVumWvt07BGlb1s2Ogu0Jym Z2jVqszMqP0eRK3zUZRwbzB7VHQghFG2OT2g6awVoJLgRDZqW3yyeJVZHMdxbTAT7+0XtvAoQHKSe +JtH4YcY25dt/kuBkXZ/U+QlGmNbd373lf/ZlGvGzCZisIBJmWkoAh12QqqhvqDh464RsUHzrSGYL UOROG28/xC90O93ywgrDXPNtFLabmZ79dmBxjEyO5AmB1VSbrDsvqplp1ALVVwfSNLv2vrwk9hQOy wvVyP0+sI2yDNKOS7f3lnq2sVC+wr4upW0hArB01CSmFIda1ZrQGsoCL9Y0slWlg7dB2y5H2I3jJF qqpObMt0I3CzfQIAWUPouc/pHk1gMOuE9Ih/WZiZ0=; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Greg Kurz Subject: Re: [PATCH v4 03/11] 9pfs: validate count sent by client with T_readdir Date: Wed, 22 Jan 2020 15:26:13 +0100 Message-ID: <11790174.e6hFKklOfu@silver> In-Reply-To: <20200122151107.7b8e5b10@bahia.lan> References: <3990d3891e8ae2074709b56449e96ab4b4b93b7d.1579567020.git.qemu_oss@crudebyte.com> <20200122151107.7b8e5b10@bahia.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 5.189.157.229 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mittwoch, 22. Januar 2020 15:11:07 CET Greg Kurz wrote: > On Tue, 21 Jan 2020 00:50:33 +0100 > > Christian Schoenebeck wrote: > > A good 9p client sends T_readdir with "count" parameter that's > > sufficiently > > smaller than client's initially negotiated msize (maximum message size). > > We perform a check for that though to avoid the server to be interrupted > > with a "Failed to encode VirtFS reply type 41" transport error message by > > bad clients. This count value constraint uses msize - 11, because 11 is > > the > > header size of R_readdir. > > This would be worth a comment... > > > Signed-off-by: Christian Schoenebeck > > --- > > > > hw/9pfs/9p.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c > > index a5fbe821d4..18370183c4 100644 > > --- a/hw/9pfs/9p.c > > +++ b/hw/9pfs/9p.c > > @@ -2426,6 +2426,7 @@ static void coroutine_fn v9fs_readdir(void *opaque) > > > > int32_t count; > > uint32_t max_count; > > V9fsPDU *pdu = opaque; > > > > + V9fsState *s = pdu->s; > > > > retval = pdu_unmarshal(pdu, offset, "dqd", &fid, > > > > &initial_offset, &max_count); > > > > @@ -2434,6 +2435,13 @@ static void coroutine_fn v9fs_readdir(void *opaque) > > > > } > > trace_v9fs_readdir(pdu->tag, pdu->id, fid, initial_offset, > > max_count); > > ... here. Something like: > > /* Enough space for a R_readdir header: size[4] Rreaddir tag[2] count[4] > */ > > I can fix this in my tree, and actually done so since I've > applied patches 1 to 3. Fine with me, thanks Greg! > Reviewed-by: Greg Kurz Best regards, Christian Schoenebeck