From: "Theodore Ts'o" <tytso@mit.edu>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
dwalsh@redhat.com, Vivek Goyal <vgoyal@redhat.com>,
"Schaufler, Casey" <casey.schaufler@intel.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"virtio-fs@redhat.com" <virtio-fs@redhat.com>,
"berrange@redhat.com" <berrange@redhat.com>,
linux-security-module <linux-security-module@vger.kernel.org>,
"selinux@vger.kernel.org" <selinux@vger.kernel.org>
Subject: Re: [RFC PATCH 0/1] xattr: Allow user.* xattr on symlink/special files if caller has CAP_SYS_RESOURCE
Date: Tue, 29 Jun 2021 12:25:48 -0400 [thread overview]
Message-ID: <YNtJjDlGoBcg4kgS@mit.edu> (raw)
In-Reply-To: <e6f9ed0d-c101-01df-3dff-85c1b38f9714@schaufler-ca.com>
On Tue, Jun 29, 2021 at 07:38:15AM -0700, Casey Schaufler wrote:
> > IMHO the biggest problem is it's badly defined when you want to actually
> > share filesystems between guests or between guests and the host.
>
> Right. The filesystem isn't the right layer for mapping xattrs.
Well, let's enumerate the alternatives:
* Some kind of stackable LSM?
* Some kind of FUSE-like scheme?
* Adding an eBPF hook which can perform the mapping
The last may be the best bet, since different use cases can use
different eBPF programs. The eBPF script can handle both the mapping
as well some kind of specialized access control with respect to what
entities are allowed set or get xattrs.
> >>> It would be lovely if there was something more granular, (e.g. allowing
> >>> user.NUMBER. or trusted.NUMBER. to be used by this particular guest).
> >> We can't do that without breaking the "kernels aren't container aware"
> >> mandate.
eBPF scripts, since they are supplied by the user *can* be container
aware. :-)
- Ted
WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: "berrange@redhat.com" <berrange@redhat.com>,
"selinux@vger.kernel.org" <selinux@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"virtio-fs@redhat.com" <virtio-fs@redhat.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"Schaufler, Casey" <casey.schaufler@intel.com>,
Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [Virtio-fs] [RFC PATCH 0/1] xattr: Allow user.* xattr on symlink/special files if caller has CAP_SYS_RESOURCE
Date: Tue, 29 Jun 2021 12:25:48 -0400 [thread overview]
Message-ID: <YNtJjDlGoBcg4kgS@mit.edu> (raw)
In-Reply-To: <e6f9ed0d-c101-01df-3dff-85c1b38f9714@schaufler-ca.com>
On Tue, Jun 29, 2021 at 07:38:15AM -0700, Casey Schaufler wrote:
> > IMHO the biggest problem is it's badly defined when you want to actually
> > share filesystems between guests or between guests and the host.
>
> Right. The filesystem isn't the right layer for mapping xattrs.
Well, let's enumerate the alternatives:
* Some kind of stackable LSM?
* Some kind of FUSE-like scheme?
* Adding an eBPF hook which can perform the mapping
The last may be the best bet, since different use cases can use
different eBPF programs. The eBPF script can handle both the mapping
as well some kind of specialized access control with respect to what
entities are allowed set or get xattrs.
> >>> It would be lovely if there was something more granular, (e.g. allowing
> >>> user.NUMBER. or trusted.NUMBER. to be used by this particular guest).
> >> We can't do that without breaking the "kernels aren't container aware"
> >> mandate.
eBPF scripts, since they are supplied by the user *can* be container
aware. :-)
- Ted
next prev parent reply other threads:[~2021-06-29 16:26 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 19:12 [RFC PATCH 0/1] xattr: Allow user.* xattr on symlink/special files if caller has CAP_SYS_RESOURCE Vivek Goyal
2021-06-25 19:12 ` [Virtio-fs] " Vivek Goyal
2021-06-25 19:12 ` [PATCH 1/1] xattr: Allow user.* xattr on symlink/special files with CAP_SYS_RESOURCE Vivek Goyal
2021-06-25 19:12 ` [Virtio-fs] " Vivek Goyal
2021-06-28 12:33 ` Christian Brauner
2021-06-28 12:33 ` [Virtio-fs] " Christian Brauner
2021-06-28 15:00 ` Vivek Goyal
2021-06-28 15:00 ` [Virtio-fs] " Vivek Goyal
2021-06-29 3:13 ` [xattr] 8d8cd767b6: ltp.setxattr02.fail kernel test robot
2021-06-29 3:13 ` [Virtio-fs] " kernel test robot
2021-06-29 3:13 ` kernel test robot
2021-06-29 3:13 ` [LTP] " kernel test robot
2021-06-29 12:59 ` Vivek Goyal
2021-06-29 12:59 ` [Virtio-fs] " Vivek Goyal
2021-06-29 12:59 ` Vivek Goyal
2021-06-29 12:59 ` [LTP] " Vivek Goyal
2021-06-25 21:49 ` [RFC PATCH 0/1] xattr: Allow user.* xattr on symlink/special files if caller has CAP_SYS_RESOURCE Schaufler, Casey
2021-06-25 21:49 ` [Virtio-fs] " Schaufler, Casey
2021-06-28 11:58 ` Dr. David Alan Gilbert
2021-06-28 11:58 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-06-28 13:17 ` Vivek Goyal
2021-06-28 13:17 ` [Virtio-fs] " Vivek Goyal
2021-06-28 13:36 ` Daniel Walsh
2021-06-28 13:36 ` [Virtio-fs] " Daniel Walsh
2021-06-28 16:04 ` Casey Schaufler
2021-06-28 16:04 ` [Virtio-fs] " Casey Schaufler
2021-06-28 16:28 ` Dr. David Alan Gilbert
2021-06-28 16:28 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-06-28 17:41 ` Casey Schaufler
2021-06-28 17:41 ` [Virtio-fs] " Casey Schaufler
2021-06-29 9:00 ` Dr. David Alan Gilbert
2021-06-29 9:00 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-06-29 14:38 ` Casey Schaufler
2021-06-29 14:38 ` [Virtio-fs] " Casey Schaufler
2021-06-29 15:20 ` Vivek Goyal
2021-06-29 15:20 ` [Virtio-fs] " Vivek Goyal
2021-06-29 16:13 ` Casey Schaufler
2021-06-29 16:13 ` [Virtio-fs] " Casey Schaufler
2021-06-29 16:35 ` Dr. David Alan Gilbert
2021-06-29 16:35 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-06-29 16:51 ` Casey Schaufler
2021-06-29 16:51 ` [Virtio-fs] " Casey Schaufler
2021-06-29 17:35 ` Vivek Goyal
2021-06-29 17:35 ` [Virtio-fs] " Vivek Goyal
2021-06-29 20:28 ` Daniel Walsh
2021-06-29 20:28 ` [Virtio-fs] " Daniel Walsh
2021-06-30 4:12 ` Theodore Ts'o
2021-06-30 4:12 ` [Virtio-fs] " Theodore Ts'o
2021-06-30 8:07 ` Dr. David Alan Gilbert
2021-06-30 8:07 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-06-30 14:47 ` Theodore Ts'o
2021-06-30 14:47 ` [Virtio-fs] " Theodore Ts'o
2021-06-30 15:01 ` Dr. David Alan Gilbert
2021-06-30 15:01 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-06-30 19:59 ` Theodore Ts'o
2021-06-30 19:59 ` [Virtio-fs] " Theodore Ts'o
2021-06-30 20:32 ` Vivek Goyal
2021-06-30 20:32 ` [Virtio-fs] " Vivek Goyal
2021-07-01 8:48 ` Dr. David Alan Gilbert
2021-07-01 8:48 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-07-01 12:21 ` Vivek Goyal
2021-07-01 12:21 ` [Virtio-fs] " Vivek Goyal
2021-07-01 13:10 ` Vivek Goyal
2021-07-01 13:10 ` [Virtio-fs] " Vivek Goyal
2021-07-01 16:58 ` Casey Schaufler
2021-07-01 16:58 ` [Virtio-fs] " Casey Schaufler
2021-06-30 16:09 ` Vivek Goyal
2021-06-30 16:09 ` [Virtio-fs] " Vivek Goyal
2021-06-30 14:27 ` Vivek Goyal
2021-06-30 14:27 ` [Virtio-fs] " Vivek Goyal
2021-06-29 16:25 ` Theodore Ts'o [this message]
2021-06-29 16:25 ` Theodore Ts'o
2021-06-28 17:22 ` Vivek Goyal
2021-06-28 17:22 ` [Virtio-fs] " Vivek Goyal
2021-06-28 18:55 ` Daniel Walsh
2021-06-28 18:55 ` [Virtio-fs] " Daniel Walsh
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