From: David Howells <dhowells@redhat.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: dhowells@redhat.com, linux-unionfs@vger.kernel.org,
linux-kernel@vger.kernel.org, drquigl <drquigl@tycho.nsa.gov>,
linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 5/7] SELinux: Handle opening of a unioned file
Date: Tue, 16 Jun 2015 22:34:33 +0100 [thread overview]
Message-ID: <16652.1434490473@warthog.procyon.org.uk> (raw)
In-Reply-To: <55805AEA.3050407@tycho.nsa.gov>
Stephen Smalley <sds@tycho.nsa.gov> wrote:
> Why are you talking about file_open()?
Because that's the focus of the patch 5/7 that this comment chain is in
response to. You said that it should have a common helper with the dentry and
inode init functions.
Also, would be good to create a common helper for use here, by
selinux_dentry_init_security(), selinux_inode_init_security(), and
may_create(). Already some seeming potential for inconsistencies
there.
Okay, I missed that you'd said may_create() too. I further assumed that you
meant that selinux_file_open_union() should use the common helper too.
> Until a process writes to the file, we just want to use the lower inode
> label, right?
No.
There are two issues:
(1) Non-fd accesses to an overlayfs file use the security label on the
overlay inode, not the lower inode, even before copy up because they go
through the inode ops of the overlayfs file first.
(2) I'm told that we want the ability to have a different label on the upper
file to that on the lower file. This is trivial in overlayfs since you
always have an overlay inode off which to hang the security label, but
tricky with unionmount since you may only have a dentry.
David
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org,
dhowells@redhat.com, linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov,
drquigl <drquigl@tycho.nsa.gov>
Subject: Re: [PATCH 5/7] SELinux: Handle opening of a unioned file
Date: Tue, 16 Jun 2015 22:34:33 +0100 [thread overview]
Message-ID: <16652.1434490473@warthog.procyon.org.uk> (raw)
In-Reply-To: <55805AEA.3050407@tycho.nsa.gov>
Stephen Smalley <sds@tycho.nsa.gov> wrote:
> Why are you talking about file_open()?
Because that's the focus of the patch 5/7 that this comment chain is in
response to. You said that it should have a common helper with the dentry and
inode init functions.
Also, would be good to create a common helper for use here, by
selinux_dentry_init_security(), selinux_inode_init_security(), and
may_create(). Already some seeming potential for inconsistencies
there.
Okay, I missed that you'd said may_create() too. I further assumed that you
meant that selinux_file_open_union() should use the common helper too.
> Until a process writes to the file, we just want to use the lower inode
> label, right?
No.
There are two issues:
(1) Non-fd accesses to an overlayfs file use the security label on the
overlay inode, not the lower inode, even before copy up because they go
through the inode ops of the overlayfs file first.
(2) I'm told that we want the ability to have a different label on the upper
file to that on the lower file. This is trivial in overlayfs since you
always have an overlay inode off which to hang the security label, but
tricky with unionmount since you may only have a dentry.
David
next prev parent reply other threads:[~2015-06-16 21:35 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
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 [this message]
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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