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bh=d1vxC8HOW8BTtV2K9h458OpZbcikKwdHEuZxxQyxtlY=; b=JulM9WaXfAunmZf495TbhCtqht+LXiYEagBTUB9u1YgglFljnQDhDxsHKKqgOnmvCI+XfF kHerUgiHDlCZ/aZeMaFCz7LTHVBqHHh4nGFvkLXbnlot5BmcTOf+5612137FVEeG+V4dh3 G+1+BJnqnfe43KwXe7kDyVZMYYxZT2g= 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-473-jo17jsGbPI2LN74CoQNyqg-1; Wed, 09 Sep 2020 07:20:22 -0400 X-MC-Unique: jo17jsGbPI2LN74CoQNyqg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9084D802B62 for ; Wed, 9 Sep 2020 11:20:21 +0000 (UTC) Received: from lpt (unknown [10.43.2.94]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 85B63838C4; Wed, 9 Sep 2020 11:20:14 +0000 (UTC) Date: Wed, 9 Sep 2020 13:20:12 +0200 From: =?iso-8859-1?B?SuFu?= Tomko To: "Dr. David Alan Gilbert (git)" Subject: Re: [PATCH v2 3/6] tools/virtiofsd: xattr name mappings: Add option Message-ID: <20200909112012.GD1377607@lpt> References: <20200827153657.111098-1-dgilbert@redhat.com> <20200827153657.111098-4-dgilbert@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200827153657.111098-4-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jtomko@redhat.com X-Mimecast-Spam-Score: 0.0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="UfEAyuTBtIjiZzX6" Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=jtomko@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/09 07:20:24 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: virtio-fs@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --UfEAyuTBtIjiZzX6 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline On a Thursday in 2020, Dr. David Alan Gilbert (git) wrote: >From: "Dr. David Alan Gilbert" > >Add an option to define mappings of xattr names so that >the client and server filesystems see different views. >This can be used to have different SELinux mappings as >seen by the guest, to run the virtiofsd with less privileges >(e.g. in a case where it can't set trusted/system/security >xattrs but you want the guest to be able to), or to isolate >multiple users of the same name; e.g. trusted attributes >used by stacking overlayfs. > >A mapping engine is used wit 3 simple rules; the rules can >be combined to allow most useful mapping scenarios. >The ruleset is defined by -o xattrmap='rules...'. > >This patch doesn't use the rule maps yet. > >Signed-off-by: Dr. David Alan Gilbert >--- > docs/tools/virtiofsd.rst | 55 ++++++++++++ > tools/virtiofsd/passthrough_ll.c | 148 +++++++++++++++++++++++++++++++ > 2 files changed, 203 insertions(+) > >diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst >index 824e713491..2efa16d3c5 100644 >--- a/docs/tools/virtiofsd.rst >+++ b/docs/tools/virtiofsd.rst >@@ -107,6 +107,60 @@ Options > performance. ``auto`` acts similar to NFS with a 1 second metadata cache > timeout. ``always`` sets a long cache lifetime at the expense of coherency. > >+xattr-mapping >+------------- >+ >+By default the name of xattr's used by the client are passed through to the server >+file system. This can be a problem where either those xattr names are used >+by something on the server (e.g. selinux client/server confusion) or if the >+virtiofsd is running in a container with restricted priviliges where it cannot privileges >+access some attributes. >+ >+A mapping of xattr names can be made using -o xattrmap=mapping where the ``mapping`` >+string consists of a series of rules. >+ >+The first matching rule terminates the mapping. >+ >+Each rule consists of a number of fields separated with a separator that is the >+first non-white space character in the rule. This separator must then be used >+for the whole rule. >+White space may be added before and after each rule. >+Using ':' as the separator a rule is of the form: >+ >+``:scope:type:key:prepend:`` >+ >+**scope** is: >+ >+- 'client' - match 'key' against a xattr name from the client for >+ setxattr/getxattr/removexattr >+- 'server' - match 'prepend' against a xattr name from the server >+ for listxattr >+- 'all' - can be used to match both cases. >+ >+**type** is one of: >+ >+- 'prefix' - If 'key' matches the client then the 'prepend' >+ is added before the name is passed to the server. >+ For a server case, the prepend is tested and stripped >+ if matching. >+ >+- 'ok' - The attribute name is OK and passed through to >+ the server unchanged. >+ >+- 'bad' - If a client tries to use this name it's >+ denied using EPERM; when the server passes an attribute >+ name matching it's hidden. >+ >+**key** is a string tested as a prefix on an attribute name originating >+on the client. It maybe empty in which case a 'client' rule >+will always match on client names. >+ >+**prepend** is a string tested as a prefix on an attribute name originiating originating >+on the server, and used as a new prefix. It maybe empty may be >+in which case a 'server' rule will always match on all names from >+the server. >+ >+ > Examples > -------- > >@@ -123,3 +177,4 @@ Export ``/var/lib/fs/vm001/`` on vhost-user UNIX domain socket > -numa node,memdev=mem \ > ... > guest# mount -t virtiofs myfs /mnt >+ git complains about trailing whitespace at EOF Jano --UfEAyuTBtIjiZzX6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEE7DTm0WabvfIr7YZ4Ak1z5KIMl5QFAl9YumsACgkQAk1z5KIM l5Ry0Af/Zjbvzw4apmipGfIqkDHTdj3ujBEvABtzHkR/E3gnyB1kpVHQX2WI/kCv DkMGNF1GjV3B7Tn1TGv/32Sel9xU0V2pIZNCjUNRGlJ9V2ct4kFDjfeVNyUKX9SS mE/OxS3aJ2whyS0kZvWBbQAqZXf8h52ffgaiSBFM3wdB5SW7KdT8SOh0IVQl4Smc A7uwojQfYI2JE3rxqJcu2Uq+dOzVCak8ZIcG5D0Vlq9upf3dSVB5+uKw8cPs0A0F F4fZCFVFCp53j4YudCPk+PDIrgjiUA0ize0pTpkriU+HUyl9yM1X1y9NNfvebonx DKIA+QxHdcS2AgtRcxcHrLm7ExRY/w== =fIpH -----END PGP SIGNATURE----- --UfEAyuTBtIjiZzX6--