From: Andy Lutomirski <luto@amacapital.net>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
David Howells <dhowells@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
USB list <linux-usb@vger.kernel.org>,
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>,
Paul Moore <paul@paul-moore.com>
Subject: Re: [RFC][PATCH 00/10] Mount, FS, Block and Keyrings notifications [ver #3]
Date: Thu, 6 Jun 2019 11:51:01 -0700 [thread overview]
Message-ID: <E7472FA4-886E-4325-87EA-9812D08CC2D3@amacapital.net> (raw)
In-Reply-To: <7afe1a85-bf19-b5b4-fdf3-69d9be475dab@schaufler-ca.com>
> On Jun 6, 2019, at 11:33 AM, Casey Schaufler <casey@schaufler-ca.com> wrote:
>
>> On 6/6/2019 10:11 AM, Andy Lutomirski wrote:
>>> On Thu, Jun 6, 2019 at 9:43 AM Casey Schaufler <casey@schaufler-ca.com> wrote:
>>> ...
>>> I don't agree. That is, I don't believe it is sufficient.
>>> There is no guarantee that being able to set a watch on an
>>> object implies that every process that can trigger the event
>>> can send it to you.
>>>
>>> Watcher has Smack label W
>>> Triggerer has Smack label T
>>> Watched object has Smack label O
>>>
>>> Relevant Smack rules are
>>>
>>> W O rw
>>> T O rw
>>>
>>> The watcher will be able to set the watch,
>>> the triggerer will be able to trigger the event,
>>> but there is nothing that would allow the watcher
>>> to receive the event. This is not a case of watcher
>>> reading the watched object, as the event is delivered
>>> without any action by watcher.
>> I think this is an example of a bogus policy that should not be
>> supported by the kernel.
>
> At this point it's pretty hard for me to care much what
> you think. You don't seem to have any insight into the
> implications of the features you're advocating, or their
> potential consequences.
>
>
Can you try to spell it out, then? A mostly or fully worked out example might help.
As Stephen said, it looks like you are considering cases where there is already a full communication channel between two processes, and you’re concerned that this new mechanism might add a side channel too. If this is wrong, can you explain how?
next prev parent reply other threads:[~2019-06-06 18:51 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 9:41 [RFC][PATCH 00/10] Mount, FS, Block and Keyrings notifications [ver #3] David Howells
2019-06-06 9:42 ` [PATCH 01/10] security: Override creds in __fput() with last fputter's creds " David Howells
2019-06-06 14:57 ` Andy Lutomirski
2019-06-06 15:06 ` David Howells
2019-06-06 17:18 ` Andy Lutomirski
2019-06-06 19:09 ` Casey Schaufler
2019-06-06 19:34 ` Andy Lutomirski
2019-06-06 9:42 ` [PATCH 02/10] General notification queue with user mmap()'able ring buffer " David Howells
2019-06-06 9:42 ` [PATCH 03/10] keys: Add a notification facility " David Howells
2019-06-06 9:42 ` [PATCH 04/10] vfs: Add a mount-notification " David Howells
2019-06-06 9:42 ` [PATCH 05/10] vfs: Add superblock notifications " David Howells
2019-06-06 9:42 ` [PATCH 06/10] fsinfo: Export superblock notification counter " David Howells
2019-06-06 9:43 ` [PATCH 07/10] Add a general, global device notification watch list " David Howells
2019-06-06 9:43 ` [PATCH 08/10] block: Add block layer notifications " David Howells
2019-06-06 9:43 ` [PATCH 09/10] usb: Add USB subsystem " David Howells
2019-06-06 14:24 ` Alan Stern
2019-06-06 14:33 ` Greg Kroah-Hartman
2019-06-06 14:55 ` Alan Stern
2019-06-06 15:31 ` Greg Kroah-Hartman
2019-06-07 6:40 ` Felipe Balbi
2019-06-07 14:01 ` Alan Stern
2019-06-11 6:28 ` Felipe Balbi
2019-06-11 13:53 ` Alan Stern
2019-06-12 6:58 ` Felipe Balbi
2019-06-06 9:43 ` [PATCH 10/10] Add sample notification program " David Howells
2019-06-06 21:21 ` Eugeniu Rosca
2019-06-06 22:52 ` David Howells
2019-06-07 14:37 ` David Howells
2019-06-06 12:32 ` [RFC][PATCH 00/10] Mount, FS, Block and Keyrings notifications " Stephen Smalley
2019-06-06 13:16 ` David Howells
2019-06-06 14:05 ` Stephen Smalley
2019-06-06 16:43 ` Casey Schaufler
2019-06-06 17:11 ` Andy Lutomirski
2019-06-06 18:33 ` Casey Schaufler
2019-06-06 18:51 ` Andy Lutomirski [this message]
2019-06-06 17:16 ` Stephen Smalley
2019-06-06 18:56 ` Casey Schaufler
2019-06-06 19:54 ` Andy Lutomirski
2019-06-06 21:17 ` David Howells
2019-06-06 21:54 ` Andy Lutomirski
2019-06-06 22:38 ` David Howells
2019-06-06 22:42 ` Andy Lutomirski
2019-06-06 22:50 ` David Howells
2019-06-06 14:34 ` Christian Brauner
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