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From: Paul Moore <paul@paul-moore.com>
To: David Howells <dhowells@redhat.com>
Cc: linux-unionfs@vger.kernel.org, selinux@tycho.nsa.gov,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] Overlayfs: Use copy-up security hooks
Date: Mon, 10 Nov 2014 10:45:37 -0500	[thread overview]
Message-ID: <3253042.xfZ6VF8OvX@sifl> (raw)
In-Reply-To: <3148.1415397940@warthog.procyon.org.uk>

On Friday, November 07, 2014 10:05:40 PM David Howells wrote:
> Paul Moore <paul@paul-moore.com> wrote:
> > So the LSM must modify the xattr in place?  I suppose that since the
> > @value is allocated to the max size it shouldn't be a problem.  Just
> > checking ...
> 
> ... And the caller must provide a maximally sized buffer (which it likely
> has to allocate anyway).
> 
> I'm not sure I really need to provide the modification thing.  I suspect a
> binary keep or discard decision is sufficient.

The docker use case we've been talking about in this thread doesn't really 
care about the on-disk file labels (xattrs) because the docker folks want to 
use context= mounts; however if someone did care about on-disk file labels for 
the upper layer in the overlayfs then they might want to modify the xattr.

-- 
paul moore
www.paul-moore.com


WARNING: multiple messages have this Message-ID (diff)
From: Paul Moore <paul@paul-moore.com>
To: David Howells <dhowells@redhat.com>
Cc: linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-unionfs@vger.kernel.org, selinux@tycho.nsa.gov,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] Overlayfs: Use copy-up security hooks
Date: Mon, 10 Nov 2014 10:45:37 -0500	[thread overview]
Message-ID: <3253042.xfZ6VF8OvX@sifl> (raw)
In-Reply-To: <3148.1415397940@warthog.procyon.org.uk>

On Friday, November 07, 2014 10:05:40 PM David Howells wrote:
> Paul Moore <paul@paul-moore.com> wrote:
> > So the LSM must modify the xattr in place?  I suppose that since the
> > @value is allocated to the max size it shouldn't be a problem.  Just
> > checking ...
> 
> ... And the caller must provide a maximally sized buffer (which it likely
> has to allocate anyway).
> 
> I'm not sure I really need to provide the modification thing.  I suspect a
> binary keep or discard decision is sufficient.

The docker use case we've been talking about in this thread doesn't really 
care about the on-disk file labels (xattrs) because the docker folks want to 
use context= mounts; however if someone did care about on-disk file labels for 
the upper layer in the overlayfs then they might want to modify the xattr.

-- 
paul moore
www.paul-moore.com

  reply	other threads:[~2014-11-10 15:45 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-05 15:42 [PATCH 0/7] Security: Provide unioned file support David Howells
2014-11-05 15:42 ` [PATCH 1/7] Security: Provide copy-up security hooks for unioned files David Howells
2014-11-06 17:46   ` Casey Schaufler
2014-11-07 14:49   ` David Howells
2014-11-07 14:49     ` David Howells
2014-11-07 21:22   ` Paul Moore
2014-11-07 21:22     ` Paul Moore
2014-11-07 22:10   ` David Howells
2014-11-07 22:10     ` David Howells
2014-11-10 15:28     ` Paul Moore
2014-11-10 15:28       ` Paul Moore
2014-11-05 15:42 ` [PATCH 2/7] Overlayfs: Use copy-up security hooks David Howells
2014-11-07 21:39   ` Paul Moore
2014-11-07 21:39     ` Paul Moore
2014-11-07 22:05   ` David Howells
2014-11-07 22:05     ` David Howells
2014-11-10 15:45     ` Paul Moore [this message]
2014-11-10 15:45       ` Paul Moore
2014-11-05 15:42 ` [PATCH 3/7] SELinux: Stub in copy-up handling David Howells
2014-11-07 21:44   ` Paul Moore
2014-11-07 21:44     ` Paul Moore
2014-11-07 22:08   ` David Howells
2014-11-07 22:08     ` David Howells
2014-11-10 15:47     ` Paul Moore
2014-11-10 15:47       ` Paul Moore
2014-11-05 15:42 ` [PATCH 4/7] Security: Pass the union-layer file path into security_file_open() David Howells
2014-11-05 15:43 ` [PATCH 5/7] SELinux: Handle opening of a unioned file David Howells
2014-11-05 16:35   ` Stephen Smalley
2014-11-06 12:03   ` David Howells
2014-11-06 12:03     ` David Howells
2014-11-06 13:13     ` Stephen Smalley
2014-11-06 13:13       ` Stephen Smalley
2014-11-06 13:34     ` David Howells
2014-11-06 13:34       ` David Howells
2014-11-27 14:15     ` David Howells
2014-11-27 14:15       ` David Howells
2014-11-06 12:27   ` David Howells
2014-11-06 12:27     ` David Howells
2014-11-06 12:27     ` David Howells
2014-11-27 17:25   ` David Howells
2014-11-27 17:25     ` David Howells
2015-06-12 15:30   ` David Howells
2015-06-12 15:30     ` David Howells
2015-06-15 12:57     ` Stephen Smalley
2015-06-15 12:57       ` Stephen Smalley
2015-06-16  9:41     ` David Howells
2015-06-16  9:41       ` David Howells
2015-06-16 16:49     ` David Howells
2015-06-16 16:49       ` David Howells
2015-06-16 17:20       ` Stephen Smalley
2015-06-16 17:20         ` Stephen Smalley
2015-06-16 21:34       ` David Howells
2015-06-16 21:34         ` David Howells
2015-06-17 14:44         ` Stephen Smalley
2015-06-17 14:44           ` Stephen Smalley
2015-06-18 10:15         ` David Howells
2015-06-18 10:15           ` David Howells
2015-06-18 12:48           ` Stephen Smalley
2015-06-18 12:48             ` Stephen Smalley
2015-06-18 15:26           ` David Howells
2015-06-18 15:26             ` David Howells
2015-06-18 10:32       ` David Howells
2015-06-18 10:32         ` David Howells
2015-06-18 12:16         ` Stephen Smalley
2015-06-18 12:16           ` Stephen Smalley
2014-11-05 15:43 ` [PATCH 6/7] SELinux: The copy-up operation must have read permission on the lower file David Howells
2014-11-05 16:43   ` Stephen Smalley
2014-11-05 17:54     ` Stephen Smalley
2014-11-06 13:39       ` Stephen Smalley
2014-11-27 14:17     ` David Howells
2014-11-27 14:17       ` David Howells
2014-11-27 14:21     ` David Howells
2014-11-27 14:21       ` David Howells
2014-11-27 14:21       ` David Howells
2014-11-05 15:43 ` [PATCH 7/7] SELinux: Check against union and lower labels for file ops on lower files David Howells
2014-11-06 17:35 ` [PATCH 0/7] Security: Provide unioned file support Casey Schaufler
2014-11-06 17:35   ` Casey Schaufler
2014-11-06 17:58 ` David Howells
2014-11-06 17:58   ` David Howells
2014-11-06 18:40   ` Casey Schaufler
2014-11-06 18:40     ` Casey Schaufler
2014-11-07 15:21   ` David Howells
2014-11-07 15:21     ` David Howells
2014-11-07 18:54     ` Daniel J Walsh
2014-11-07 18:54       ` Daniel J Walsh
2014-11-09  1:31       ` Casey Schaufler
2014-11-09  1:31         ` Casey Schaufler
2014-11-10 13:59         ` Daniel J Walsh
2014-11-10 13:59           ` Daniel J Walsh

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