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From: David Howells <dhowells@redhat.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: dhowells@redhat.com, Andy Lutomirski <luto@kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	raven@themaw.net, Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	linux-block@vger.kernel.org, keyrings@vger.kernel.org,
	LSM List <linux-security-module@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Rational model for UID based controls
Date: Wed, 05 Jun 2019 17:56:47 +0100	[thread overview]
Message-ID: <18357.1559753807@warthog.procyon.org.uk> (raw)
In-Reply-To: <e4c19d1b-9827-5949-ecb8-6c3cb4648f58@schaufler-ca.com>

Casey Schaufler <casey@schaufler-ca.com> wrote:

> YES!

I'm trying to decide if that's fervour or irritation at this point ;-)

> And it would be really great if you put some thought into what
> a rational model would be for UID based controls, too.

I have put some thought into it, but I don't see a single rational model.  It
depends very much on the situation.

In any case, that's what I was referring to when I said I might need to call
inode_permission().  But UIDs don't exist for all filesystems, for example,
and there are no UIDs on superblocks, mount objects or hardware events.

Now, I could see that you ignore UIDs on things like keys and
hardware-triggered events, but how does this interact with things like mount
watches that see directories that have UIDs?

Are you advocating making it such that process B can only see events triggered
by process A if they have the same UID, for example?

David

WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: dhowells@redhat.com, Andy Lutomirski <luto@kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	raven@themaw.net, Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	linux-block@vger.kernel.org, keyrings@vger.kernel.org,
	LSM List <linux-security-module@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Rational model for UID based controls
Date: Wed, 05 Jun 2019 16:56:47 +0000	[thread overview]
Message-ID: <18357.1559753807@warthog.procyon.org.uk> (raw)
In-Reply-To: <e4c19d1b-9827-5949-ecb8-6c3cb4648f58@schaufler-ca.com>

Casey Schaufler <casey@schaufler-ca.com> wrote:

> YES!

I'm trying to decide if that's fervour or irritation at this point ;-)

> And it would be really great if you put some thought into what
> a rational model would be for UID based controls, too.

I have put some thought into it, but I don't see a single rational model.  It
depends very much on the situation.

In any case, that's what I was referring to when I said I might need to call
inode_permission().  But UIDs don't exist for all filesystems, for example,
and there are no UIDs on superblocks, mount objects or hardware events.

Now, I could see that you ignore UIDs on things like keys and
hardware-triggered events, but how does this interact with things like mount
watches that see directories that have UIDs?

Are you advocating making it such that process B can only see events triggered
by process A if they have the same UID, for example?

David

  parent reply	other threads:[~2019-06-05 16:57 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-04 16:34 [RFC][PATCH 0/8] Mount, FS, Block and Keyrings notifications [ver #2] David Howells
2019-06-04 16:34 ` David Howells
2019-06-04 16:35 ` [PATCH 1/8] security: Override creds in __fput() with last fputter's creds " David Howells
2019-06-04 16:35   ` David Howells
2019-06-04 16:35   ` David Howells
2019-06-04 18:15   ` Andy Lutomirski
2019-06-04 18:15     ` Andy Lutomirski
2019-06-04 16:35 ` [PATCH 2/8] General notification queue with user mmap()'able ring buffer " David Howells
2019-06-04 16:35   ` David Howells
2019-06-04 16:35 ` [PATCH 3/8] keys: Add a notification facility " David Howells
2019-06-04 16:35   ` David Howells
2019-06-04 16:35 ` [PATCH 4/8] vfs: Add a mount-notification " David Howells
2019-06-04 16:35   ` David Howells
2019-06-04 16:35 ` [PATCH 5/8] vfs: Add superblock notifications " David Howells
2019-06-04 16:35   ` David Howells
2019-06-04 16:36 ` [PATCH 6/8] fsinfo: Export superblock notification counter " David Howells
2019-06-04 16:36   ` David Howells
2019-06-04 16:36 ` [PATCH 7/8] block: Add block layer notifications " David Howells
2019-06-04 16:36   ` David Howells
2019-06-04 16:36 ` [PATCH 8/8] Add sample notification program " David Howells
2019-06-04 16:36   ` David Howells
2019-06-04 17:43 ` [RFC][PATCH 0/8] Mount, FS, Block and Keyrings notifications " Andy Lutomirski
2019-06-04 17:43   ` Andy Lutomirski
2019-06-04 20:31   ` Casey Schaufler
2019-06-04 20:31     ` Casey Schaufler
2019-06-04 21:05     ` Andy Lutomirski
2019-06-04 21:05       ` Andy Lutomirski
2019-06-04 22:03       ` Casey Schaufler
2019-06-04 22:03         ` Casey Schaufler
2019-06-05  8:41   ` David Howells
2019-06-05  8:41     ` David Howells
2019-06-05 14:50     ` Casey Schaufler
2019-06-05 14:50       ` Casey Schaufler
2019-06-05 16:04       ` Andy Lutomirski
2019-06-05 16:04         ` Andy Lutomirski
2019-06-05 17:01         ` Casey Schaufler
2019-06-05 17:01           ` Casey Schaufler
2019-06-05 17:47           ` Andy Lutomirski
2019-06-05 17:47             ` Andy Lutomirski
2019-06-05 18:12             ` Casey Schaufler
2019-06-05 18:12               ` Casey Schaufler
2019-06-05 18:25             ` Stephen Smalley
2019-06-05 18:25               ` Stephen Smalley
2019-06-05 19:28               ` Greg KH
2019-06-05 19:28                 ` Greg KH
2019-06-05 21:01                 ` Stephen Smalley
2019-06-05 21:01                   ` Stephen Smalley
2019-06-05 16:56     ` David Howells [this message]
2019-06-05 16:56       ` Rational model for UID based controls David Howells
2019-06-05 17:40       ` Casey Schaufler
2019-06-05 17:40         ` Casey Schaufler
2019-06-05 21:06       ` David Howells
2019-06-05 21:06         ` David Howells
2019-06-05 17:21     ` [RFC][PATCH 0/8] Mount, FS, Block and Keyrings notifications [ver #2] David Howells
2019-06-05 17:21       ` David Howells
2019-06-04 20:39 ` David Howells
2019-06-04 20:39   ` David Howells
2019-06-04 20:57   ` Andy Lutomirski
2019-06-04 20:57     ` Andy Lutomirski
     [not found]     ` <CAB9W1A0AgMYOwGx9c-TmAt=1O6Bjsr2P3Nhd=2+QV39dgw0CrA@mail.gmail.com>
2019-06-05  4:19       ` Andy Lutomirski
2019-06-05  4:19         ` Andy Lutomirski
2019-06-05 13:47         ` Stephen Smalley
2019-06-05 13:47           ` Stephen Smalley
2019-06-04 21:11   ` Casey Schaufler
2019-06-04 21:11     ` Casey Schaufler

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