From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 17 Mar 2021 11:18:57 -0400 From: Vivek Goyal Message-ID: <20210317151857.GC324911@redhat.com> References: <20210316160147.289193-1-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: Subject: Re: [Virtio-fs] [PATCH 0/1] fuse: acl: Send file mode updates using SETATTR List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luis Henriques Cc: linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com, seth.forshee@canonical.com, miklos@szeredi.hu On Wed, Mar 17, 2021 at 02:29:03PM +0000, Luis Henriques wrote: > On Tue, Mar 16, 2021 at 12:01:46PM -0400, Vivek Goyal wrote: > > Hi Miklos, > >=20 > > Please find attached a patch to fix the SGID clearing issue upon=20 > > ACL change.=20 > >=20 > > Luis reported that currently fstests generic/375 fails on virtiofs. And > > reason being that we don't clear SGID when it should be. > >=20 > > Setting ACL can lead to file mode change. And this in-turn also can > > lead to clearing SGID bit if. > >=20 > > - None of caller's groups match file owner group. > > AND > > - Caller does not have CAP_FSETID. > >=20 > > Current implementation relies on server updating the mode. But file > > server does not have enough information to do so.=20 > >=20 > > Initially I thought of sending CAP_FSETID information to server but > > then I realized, it is just one of the pieces. What about all the > > groups caller is a member of. If this has to work correctly, then > > all the information will have to be sent to virtiofsd somehow. Just > > sending CAP_FSETID information required adding V2 of fuse_setxattr_in > > because we don't have any space for sending extra information. > >=20 > > https://github.com/rhvgoyal/linux/commit/681cf5bdbba9c965c3dbd4337c16e9= b17f27debe > >=20 > > Also this approach will not work with idmapped mounts because server > > does not have information about idmapped mappings. > >=20 > > So I started to look at the approach of sending file mode updates > > using SETATTR. As filesystems like 9pfs and ceph are doing. This > > seems simpler approach. Though it has its issues too. > >=20 > > - File mode update and setxattr(system.posix_acl_access) are not atomic. >=20 > After reviewing (and testing) the patch, the only comment I have is that > we should at least pr_warn() an eventual failure in setxattr(). But f > that operation fails at that point, probably something went wrong on the > other side Hi Luis, If setxattr failed, user will get the error.=20 I guess pr_warn() could help with figuring out that there was a side affect of failed failed setxattr operation. (mode changed). I will add something. > and the kernel is unlikely to be able to revert the mode > changes anyway. Interestingly ceph code seems to revert mode changes if setxattr fails. I think for now I am happy with just a pr_warn(). >=20 > (And a nit: your patch seems to require some whitespaces clean-up.) Will check it and fix it and post V2. Thanks Vivek >=20 > Cheers, > -- > Lu=EDs >=20 >=20 > > None of the approaches seem very clean to me. But sending SETATTR > > explicitly seems to be lesser of two evils to me at this point of time. > > Hence I am proposing this patch.=20 > >=20 > > I have run fstests acl tests and they pass. (./check -g acl). > >=20 > > Corresponding virtiofsd patches are here. > >=20 > > https://github.com/rhvgoyal/qemu/commits/acl-sgid-setattr > >=20 > > What do you think. > >=20 > > Vivek Goyal (1): > > fuse: Add a mode where fuse client sends mode changes on ACL change > >=20 > > fs/fuse/acl.c | 54 ++++++++++++++++++++++++++++++++++++--- > > fs/fuse/dir.c | 11 ++++---- > > fs/fuse/fuse_i.h | 9 ++++++- > > fs/fuse/inode.c | 4 ++- > > include/uapi/linux/fuse.h | 5 ++++ > > 5 files changed, 71 insertions(+), 12 deletions(-) > >=20 > > --=20 > > 2.25.4 > >=20 >=20 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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,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 43EC2C433E9 for ; Wed, 17 Mar 2021 15:50:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 063D364F80 for ; Wed, 17 Mar 2021 15:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232514AbhCQPtt (ORCPT ); Wed, 17 Mar 2021 11:49:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:40244 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232495AbhCQPtR (ORCPT ); Wed, 17 Mar 2021 11:49:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615996156; 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=ojM9g5bXUmb7n3KgDuQWnhqjZ24DPefjMRpNBzV+8t4=; b=W4+G3i0oAafLiaWb9OSLXCd8l0XNcubO3n2pU4rniCZNwDVPmvCpes2xVQHbakndZMgb6e s22gKXMQIyH7PtMPWK70q2SzlIq+mK6jqtHPWXLs4aY8J/6UD/TvVfxWoZQY3LiJkM/2c/ 7oppovShzNs/7M5psXbEBmlYomiCL2g= 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-368-x5NourVEOhGzr9N7HRFZ1A-1; Wed, 17 Mar 2021 11:19:02 -0400 X-MC-Unique: x5NourVEOhGzr9N7HRFZ1A-1 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 8EA8E100945F; Wed, 17 Mar 2021 15:19:01 +0000 (UTC) Received: from horse.redhat.com (ovpn-116-32.rdu2.redhat.com [10.10.116.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 48FEF10074FC; Wed, 17 Mar 2021 15:18:58 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id AC0FD220BCF; Wed, 17 Mar 2021 11:18:57 -0400 (EDT) Date: Wed, 17 Mar 2021 11:18:57 -0400 From: Vivek Goyal To: Luis Henriques Cc: linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com, miklos@szeredi.hu, dgilbert@redhat.com, seth.forshee@canonical.com Subject: Re: [PATCH 0/1] fuse: acl: Send file mode updates using SETATTR Message-ID: <20210317151857.GC324911@redhat.com> References: <20210316160147.289193-1-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Mar 17, 2021 at 02:29:03PM +0000, Luis Henriques wrote: > On Tue, Mar 16, 2021 at 12:01:46PM -0400, Vivek Goyal wrote: > > Hi Miklos, > > > > Please find attached a patch to fix the SGID clearing issue upon > > ACL change. > > > > Luis reported that currently fstests generic/375 fails on virtiofs. And > > reason being that we don't clear SGID when it should be. > > > > Setting ACL can lead to file mode change. And this in-turn also can > > lead to clearing SGID bit if. > > > > - None of caller's groups match file owner group. > > AND > > - Caller does not have CAP_FSETID. > > > > Current implementation relies on server updating the mode. But file > > server does not have enough information to do so. > > > > Initially I thought of sending CAP_FSETID information to server but > > then I realized, it is just one of the pieces. What about all the > > groups caller is a member of. If this has to work correctly, then > > all the information will have to be sent to virtiofsd somehow. Just > > sending CAP_FSETID information required adding V2 of fuse_setxattr_in > > because we don't have any space for sending extra information. > > > > https://github.com/rhvgoyal/linux/commit/681cf5bdbba9c965c3dbd4337c16e9b17f27debe > > > > Also this approach will not work with idmapped mounts because server > > does not have information about idmapped mappings. > > > > So I started to look at the approach of sending file mode updates > > using SETATTR. As filesystems like 9pfs and ceph are doing. This > > seems simpler approach. Though it has its issues too. > > > > - File mode update and setxattr(system.posix_acl_access) are not atomic. > > After reviewing (and testing) the patch, the only comment I have is that > we should at least pr_warn() an eventual failure in setxattr(). But f > that operation fails at that point, probably something went wrong on the > other side Hi Luis, If setxattr failed, user will get the error. I guess pr_warn() could help with figuring out that there was a side affect of failed failed setxattr operation. (mode changed). I will add something. > and the kernel is unlikely to be able to revert the mode > changes anyway. Interestingly ceph code seems to revert mode changes if setxattr fails. I think for now I am happy with just a pr_warn(). > > (And a nit: your patch seems to require some whitespaces clean-up.) Will check it and fix it and post V2. Thanks Vivek > > Cheers, > -- > Luís > > > > None of the approaches seem very clean to me. But sending SETATTR > > explicitly seems to be lesser of two evils to me at this point of time. > > Hence I am proposing this patch. > > > > I have run fstests acl tests and they pass. (./check -g acl). > > > > Corresponding virtiofsd patches are here. > > > > https://github.com/rhvgoyal/qemu/commits/acl-sgid-setattr > > > > What do you think. > > > > Vivek Goyal (1): > > fuse: Add a mode where fuse client sends mode changes on ACL change > > > > fs/fuse/acl.c | 54 ++++++++++++++++++++++++++++++++++++--- > > fs/fuse/dir.c | 11 ++++---- > > fs/fuse/fuse_i.h | 9 ++++++- > > fs/fuse/inode.c | 4 ++- > > include/uapi/linux/fuse.h | 5 ++++ > > 5 files changed, 71 insertions(+), 12 deletions(-) > > > > -- > > 2.25.4 > > >