From nobody Sat Feb 7 07:12:17 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1625479964797938.5659239589484; Mon, 5 Jul 2021 03:12:44 -0700 (PDT) Received: from localhost ([::1]:58642 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m0Lal-0002Qm-KU for importer@patchew.org; Mon, 05 Jul 2021 06:12:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38862) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m0LSA-0001KS-Tm for qemu-devel@nongnu.org; Mon, 05 Jul 2021 06:03:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:40133) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m0LS8-0001BF-26 for qemu-devel@nongnu.org; Mon, 05 Jul 2021 06:03:50 -0400 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-562-L0w6WDp2M9yKKhced1Rk0w-1; Mon, 05 Jul 2021 06:03:46 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2091B1835AC3; Mon, 5 Jul 2021 10:03:45 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-114-11.ams2.redhat.com [10.36.114.11]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1334260C0F; Mon, 5 Jul 2021 10:03:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625479427; 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=bsA2HH6yfLKkqV4WkmgRRh9p9oulko4q1HRmnuira8c=; b=WISnk+8g7iyyXj56kP89sPp5YO/qhnimwaQNcgaEMEWH3xiBEb6qA5VAp3LKleYzqbH5qM 06yqvnF46TM3OtroZpYYQDw8OH6I4kMlrSpSvcEAz6xsfLq/3b8oVwacKinFNZC+5mdSpa MJWpsjeqC+benjf8RvZ7x5JzD3e5kyU= X-MC-Unique: L0w6WDp2M9yKKhced1Rk0w-1 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, berrange@redhat.com, linfeng23@huawei.com, groug@kaod.org, huangy81@chinatelecom.cn, lvivier@redhat.com, lizhijian@cn.fujitsu.com, peterx@redhat.com, vgoyal@redhat.com Subject: [PULL 09/19] virtiofsd: Don't allow file creation with FUSE_OPEN Date: Mon, 5 Jul 2021 11:02:25 +0100 Message-Id: <20210705100235.157093-10-dgilbert@redhat.com> In-Reply-To: <20210705100235.157093-1-dgilbert@redhat.com> References: <20210705100235.157093-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.441, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: leobras@redhat.com, stefanha@redhat.com, quintela@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1625479966006100001 Content-Type: text/plain; charset="utf-8" From: Greg Kurz A well behaved FUSE client uses FUSE_CREATE to create files. It isn't supposed to pass O_CREAT along a FUSE_OPEN request, as documented in the "fuse_lowlevel.h" header : /** * Open a file * * Open flags are available in fi->flags. The following rules * apply. * * - Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be * filtered out / handled by the kernel. But if the client happens to do it anyway, the server ends up passing this flag to open() without the mandatory mode_t 4th argument. Since open() is a variadic function, glibc will happily pass whatever it finds on the stack to the syscall. If this file is compiled with -D_FORTIFY_SOURCE=3D2, glibc will even detect that and abort: *** invalid openat64 call: O_CREAT or O_TMPFILE without mode ***: terminated Specifying O_CREAT with FUSE_OPEN is a protocol violation. Check this in do_open(), print out a message and return an error to the client, EINVAL like we already do when fuse_mbuf_iter_advance() fails. The FUSE filesystem doesn't currently support O_TMPFILE, but the very same would happen if O_TMPFILE was passed in a FUSE_OPEN request. Check that as well. Signed-off-by: Greg Kurz Message-Id: <20210624101809.48032-1-groug@kaod.org> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert --- tools/virtiofsd/fuse_lowlevel.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowleve= l.c index 7fe2cef1eb..3d725bcba2 100644 --- a/tools/virtiofsd/fuse_lowlevel.c +++ b/tools/virtiofsd/fuse_lowlevel.c @@ -1084,6 +1084,12 @@ static void do_open(fuse_req_t req, fuse_ino_t nodei= d, return; } =20 + /* File creation is handled by do_create() or do_mknod() */ + if (arg->flags & (O_CREAT | O_TMPFILE)) { + fuse_reply_err(req, EINVAL); + return; + } + memset(&fi, 0, sizeof(fi)); fi.flags =3D arg->flags; fi.kill_priv =3D arg->open_flags & FUSE_OPEN_KILL_SUIDGID; --=20 2.31.1