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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 5A529C07E95 for ; Wed, 7 Jul 2021 10:38:27 +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 06C4B61C60 for ; Wed, 7 Jul 2021 10:38:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 06C4B61C60 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]:32812 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m14wk-0006Ix-2b for qemu-devel@archiver.kernel.org; Wed, 07 Jul 2021 06:38:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50992) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m14vz-0004sO-C8 for qemu-devel@nongnu.org; Wed, 07 Jul 2021 06:37:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35306) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m14vw-0000nN-An for qemu-devel@nongnu.org; Wed, 07 Jul 2021 06:37:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625654254; 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: in-reply-to:in-reply-to:references:references; bh=eHGbyNtsw80y5fl6q2AI6FG3wZXkmsRFcS4nkMFbcyU=; b=NVxo+EV4pV+/ugB04NaXy3ZEPLiu5uw5xJIkcVjypd9X+861ip9WalkO8nWsG3KAkkEi+a +yfP33CbIJvflCotdjgnVPOh+P0Id2P4PCn8eV9AIUIvgJ+jBCdCUgF9+NWvHLu0gN/7Qv aWkR/JH3V6hX+T+w7hV7L+9O5+npBXg= 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-585-rOC3gDFhN0aHdTX0o5SKKQ-1; Wed, 07 Jul 2021 06:37:33 -0400 X-MC-Unique: rOC3gDFhN0aHdTX0o5SKKQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B20985074B; Wed, 7 Jul 2021 10:37:32 +0000 (UTC) Received: from redhat.com (ovpn-112-88.ams2.redhat.com [10.36.112.88]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E216B5D9D3; Wed, 7 Jul 2021 10:37:31 +0000 (UTC) Date: Wed, 7 Jul 2021 12:37:30 +0200 From: Kevin Wolf To: Max Reitz Subject: Re: [PATCH v2 2/6] export/fuse: Add allow-other option Message-ID: References: <20210625142317.271673-1-mreitz@redhat.com> <20210625142317.271673-3-mreitz@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210625142317.271673-3-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.442, 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=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 25.06.2021 um 16:23 hat Max Reitz geschrieben: > Without the allow_other mount option, no user (not even root) but the > one who started qemu/the storage daemon can access the export. Allow > users to configure the export such that such accesses are possible. > > While allow_other is probably what users want, we cannot make it an > unconditional default, because passing it is only possible (for non-root > users) if the global fuse.conf configuration file allows it. Thus, the > default is an 'auto' mode, in which we first try with allow_other, and > then fall back to without. > > FuseExport.allow_other reports whether allow_other was actually used as > a mount option or not. Currently, this information is not used, but a > future patch will let this field decide whether e.g. an export's UID and > GID can be changed through chmod. > > One notable thing about 'auto' mode is that libfuse may print error > messages directly to stderr, and so may fusermount (which it executes). > Our export code cannot really filter or hide them. Therefore, if 'auto' > fails its first attempt and has to fall back, fusermount will print an > error message that mounting with allow_other failed. > > This behavior necessitates a change to iotest 308, namely we need to > filter out this error message (because if the first attempt at mounting > with allow_other succeeds, there will be no such message). > > Furthermore, common.rc's _make_test_img should use allow-other=off for > FUSE exports, because iotests generally do not need to access images > from other users, so allow-other=on or allow-other=auto have no > advantage. OTOH, allow-other=on will not work on systems where > user_allow_other is disabled, and with allow-other=auto, we get said > error message that we would need to filter out again. Just disabling > allow-other is simplest. > > Signed-off-by: Max Reitz > --- > qapi/block-export.json | 33 ++++++++++++++++++++++++++++++++- > block/export/fuse.c | 28 +++++++++++++++++++++++----- > tests/qemu-iotests/308 | 6 +++++- > tests/qemu-iotests/common.rc | 6 +++++- > 4 files changed, 65 insertions(+), 8 deletions(-) > > diff --git a/qapi/block-export.json b/qapi/block-export.json > index e819e70cac..0ed63442a8 100644 > --- a/qapi/block-export.json > +++ b/qapi/block-export.json > @@ -120,6 +120,23 @@ > '*logical-block-size': 'size', > '*num-queues': 'uint16'} } > > +## > +# @FuseExportAllowOther: > +# > +# Possible allow_other modes for FUSE exports. > +# > +# @off: Do not pass allow_other as a mount option. > +# > +# @on: Pass allow_other as a mount option. > +# > +# @auto: Try mounting with allow_other first, and if that fails, retry > +# without allow_other. > +# > +# Since: 6.1 > +## > +{ 'enum': 'FuseExportAllowOther', > + 'data': ['off', 'on', 'auto'] } Why not use the generic OnOffAuto type from common.json? But since the external interface is unaffected so we can later change this as a code cleanup and soft freeze is approaching, I won't consider this a blocker. Kevin