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From: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
To: Daniel Mack <daniel-cYrQPVfZoowdnm+yROfE0A@public.gmane.org>
Cc: Greg Kroah-Hartman
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	John Stultz <john.stultz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>,
	Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Marcel Holtmann <marcel-kz+m5ild9QBg9hUCZPvPmw@public.gmane.org>,
	Ryan Lortie <desrt-0xnayjDhYQY@public.gmane.org>,
	Bastien Nocera <hadess-0MeiytkfxGOsTnJN9+BGXg@public.gmane.org>,
	David Herrmann
	<dh.herrmann-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Djalal Harouni <tixxdz-Umm1ozX2/EEdnm+yROfE0A@public.gmane.org>,
	Simon McVittie
	<simon.mcvittie-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>,
	alban.crequy-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org,
	Javier Martinez Canillas
	<javier.martinez-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>,
	Tom Gundersen <teg-B22kvLQNl6c@public.gmane.org>
Subject: Re: kdbus: add code to gather metadata
Date: Thu, 30 Oct 2014 07:07:57 -0700	[thread overview]
Message-ID: <CALCETrWjOS0AHF33zN0Vy1NC1441To7AgNPge3sKCz8bn2d8gg@mail.gmail.com> (raw)
In-Reply-To: <5451FA9B.8070501-cYrQPVfZoowdnm+yROfE0A@public.gmane.org>

On Thu, Oct 30, 2014 at 1:45 AM, Daniel Mack <daniel-cYrQPVfZoowdnm+yROfE0A@public.gmane.org> wrote:
>
> 1. At open() time, So we can tell peers (through KDBUS_CMD_CONN_INFO)
> about the credentials a connection had when it was created with
> KDBUS_CMD_HELLO.

Then the API that tells peers about this information needs to make
this very clear.

>
> 2. When a new bus is created through KDBUS_CMD_BUS_MAKE, so peers can
> later query the credentials of the owner of the bus they're connected to.
>

Ditto.  Although, why on earth should a bus have credentials?  This
sounds like a misdesign.  It seems to me that this type of policy
belongs all the way in userspace.  If you want a bus, you ask the
owner of the entire domain to make you a bus.  Or you make it yourself
and hand off references in some authenticated way.

> 3. When we dispatch a KDBUS_CMD_MSG_SEND ioctl(), because we want to
> attach the metadata that was authoritative when the message was sent.
> IOW: We want metadata that actually matches the message payload.
>

What does that "metadata that actually matches the message payload"
mean?  If I create an endpoint and delegate some processing to a less
privileged child, other things on the bus MUST NOT be able to detect
that delegation in any sensible design.  Otherwise everything will
appear to work in testing because other processes never checked the
problematic credential, but then it will randomly fail because someone
decided to do something daft and validate my unprivileged child's
argv[0], which is, of course, not what they expected.

I suspect that, if you make credential sending opt-in, you will
quickly discover that the current model for which credentials matter
makes no sense.

>> And the ns_eq stuff is too far buried (and not even contained in this
>> patch!) to be easily verified as being correct, whatever correct means
>> in that context.
>
> I see that. As I explained earlier in my reply to Eric, we've chosen to
> submit the patch set this way to keep the reply threading clean, so it
> was some sort of a trade-off. Still, I think the best way to review it
> is to pull in Greg's patches and look at the actual files.

This wasn't a comment about the threading.  The call, in the patches
in the git tree, is buried and very difficult to follow.

--Andy

  parent reply	other threads:[~2014-10-30 14:07 UTC|newest]

Thread overview: 116+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-29 22:00 [PATCH 00/12] Add kdbus implementation Greg Kroah-Hartman
2014-10-29 22:00 ` kdbus: add documentation Greg Kroah-Hartman
2014-10-30 12:20   ` Peter Meerwald
     [not found]     ` <alpine.DEB.2.02.1410301231040.32212-jW+XmwGofnusTnJN9+BGXg@public.gmane.org>
2014-11-02  1:29       ` Greg Kroah-Hartman
2014-10-29 22:00 ` kdbus: add driver skeleton, ioctl entry points and utility functions Greg Kroah-Hartman
     [not found]   ` <1414620056-6675-4-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-10-30  3:50     ` Eric W. Biederman
2014-10-30 23:45     ` Thomas Gleixner
2014-10-31  0:23       ` Jiri Kosina
     [not found]         ` <alpine.LRH.2.00.1410310114290.11562-1ReQVI26iDCaZKY3DrU6dA@public.gmane.org>
2014-10-31  0:42           ` Thomas Gleixner
2014-10-29 22:00 ` kdbus: add connection, queue handling and message validation code Greg Kroah-Hartman
     [not found]   ` <87k33iw759.fsf@x220.int.ebiederm.org>
     [not found]     ` <87k33iw759.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-30  3:55       ` Andy Lutomirski
2014-10-30  9:06         ` Djalal Harouni
2014-10-29 22:00 ` kdbus: add code to gather metadata Greg Kroah-Hartman
     [not found]   ` <1414620056-6675-7-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-10-29 22:33     ` Andy Lutomirski
     [not found]       ` <CALCETrWqbpxk83L0k0_78JZCO+ntZhx_hHMcRu=vxs6VE2f5JQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30  0:13         ` Andy Lutomirski
     [not found]           ` <CALCETrVkuKxMMEw3HBEOZoFUuw8PndXtB13+bLWmcp_E34SaFw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30  8:45             ` Daniel Mack
     [not found]               ` <5451FA9B.8070501-cYrQPVfZoowdnm+yROfE0A@public.gmane.org>
2014-10-30 14:07                 ` Andy Lutomirski [this message]
     [not found]                   ` <CALCETrWjOS0AHF33zN0Vy1NC1441To7AgNPge3sKCz8bn2d8gg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30 15:54                     ` Daniel Mack
     [not found]                       ` <54525F32.3040502-cYrQPVfZoowdnm+yROfE0A@public.gmane.org>
2014-10-30 21:01                         ` Andy Lutomirski
     [not found]                           ` <CALCETrV6MLYUQN6mqZbH=FrLyrETVoemtdC05po8+X=6SKQ70A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-01 11:05                             ` Daniel Mack
     [not found]                               ` <5454BE6E.5040507-cYrQPVfZoowdnm+yROfE0A@public.gmane.org>
2014-11-01 16:19                                 ` Andy Lutomirski
     [not found]                                   ` <CALCETrXxx4juUGA3mwOxq0BtErM0kj7_THxiO5LwCVLzCXnd2A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-03 12:00                                     ` Simon McVittie
     [not found]                                       ` <54576E48.40800-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
2014-11-03 17:05                                         ` Andy Lutomirski
2014-10-30  8:09         ` Daniel Mack
2014-10-29 22:00 ` kdbus: add code for notifications and matches Greg Kroah-Hartman
2014-10-29 22:00 ` kdbus: add code for buses, domains and endpoints Greg Kroah-Hartman
     [not found]   ` <1414620056-6675-9-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-10-30  3:59     ` Eric W. Biederman
2014-10-30  9:58       ` Djalal Harouni
2014-10-30 12:15         ` Eric W. Biederman
     [not found]           ` <87wq7hiwjb.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-30 14:48             ` Djalal Harouni
2014-10-30 14:58               ` Andy Lutomirski
2014-10-30 18:08                 ` Djalal Harouni
2014-10-30 18:46                   ` Simon McVittie
     [not found]                     ` <54528798.40107-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
2014-11-05 19:59                       ` Djalal Harouni
2014-10-30 20:37                   ` Andy Lutomirski
2014-10-30 21:47                     ` Alex Elsayed
2014-10-30 22:00                       ` Andy Lutomirski
2014-10-30 23:38     ` How Not To Use kref (was Re: kdbus: add code for buses, domains and endpoints) Al Viro
     [not found]       ` <20141030233801.GF7996-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2014-10-31 18:00         ` Linus Torvalds
     [not found]           ` <CA+55aFxB=jWGvPH3TMhB=ungOg9TBai5Ak-ma5vChBB-H2AgnQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-31 19:56             ` Al Viro
2014-11-04  9:11         ` David Herrmann
2014-10-31  1:39     ` kdbus: add code for buses, domains and endpoints Al Viro
     [not found]       ` <20141031013922.GG7996-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2014-10-31  9:55         ` Daniel Mack
2014-10-29 22:00 ` kdbus: add name registry implementation Greg Kroah-Hartman
2014-10-29 22:00 ` kdbus: add policy database implementation Greg Kroah-Hartman
2014-10-29 22:00 ` kdbus: add Makefile, Kconfig and MAINTAINERS entry Greg Kroah-Hartman
2014-10-29 22:00 ` kdbus: add selftests Greg Kroah-Hartman
     [not found]   ` <1414620056-6675-13-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-10-30  8:31     ` Arnd Bergmann
2014-11-14  3:42     ` Michael Ellerman
2014-11-14  8:56       ` Daniel Mack
2014-10-29 22:15 ` [PATCH 00/12] Add kdbus implementation Andy Lutomirski
     [not found]   ` <CALCETrWrxc8foPYbRPtxwNX0sHK_=vLFLDXXyXu+2U2=B+=qCQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-29 22:27     ` Greg Kroah-Hartman
2014-10-29 22:34       ` Andy Lutomirski
     [not found]       ` <20141029222729.GB8129-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2014-10-30  2:27         ` Andy Lutomirski
     [not found]           ` <CALCETrVxvF2ie=vVgpjeqikn+nci_9jyKfU4s3t=4cjyNZNaNQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30  4:20             ` Eric W. Biederman
     [not found]               ` <87bnourxx4.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-30 10:15                 ` Tom Gundersen
     [not found]                   ` <CAG-2HqUChohNrRSdXzckSiv8ZUYwFLMvRTc41Uo7-b-qmkSFMQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30 12:02                     ` Eric W. Biederman
2014-10-30 13:48                     ` Andy Lutomirski
     [not found] ` <1414620056-6675-1-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-10-29 22:00   ` kdbus: add header file Greg Kroah-Hartman
     [not found]     ` <1414620056-6675-3-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-10-30  8:20       ` Arnd Bergmann
2014-10-30 11:02         ` Tom Gundersen
2014-10-30 11:26           ` Arnd Bergmann
2014-10-30 11:52             ` Daniel Mack
2014-10-30 12:03               ` Arnd Bergmann
2014-10-31 10:03                 ` Daniel Mack
2014-10-29 22:00   ` kdbus: add connection pool implementation Greg Kroah-Hartman
2014-10-29 22:15   ` [PATCH 00/12] Add kdbus implementation Greg KH
     [not found]     ` <20141029221505.GA7812-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2014-10-30  4:04       ` Eric W. Biederman
     [not found]         ` <87egtqurrp.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-30  7:12           ` Daniel Mack
2014-10-29 22:19   ` Andy Lutomirski
2014-10-29 22:25     ` Greg Kroah-Hartman
2014-10-29 22:28       ` Andy Lutomirski
2014-10-29 22:36         ` Andy Lutomirski
     [not found]         ` <CALCETrX6vf7cKy=XDhDtn9hn1W930MRxBa=pk93RnyuZ-EaNyw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30  7:44           ` Daniel Mack
     [not found]     ` <CALCETrUBegZ4F1sKq3LxUgANX3=syYOrqOp9=F--g9pkVHHgUA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-05 14:34       ` Daniel Mack
2014-10-29 23:00   ` Jiri Kosina
     [not found]     ` <alpine.LRH.2.00.1410292354480.11562-1ReQVI26iDCaZKY3DrU6dA@public.gmane.org>
2014-10-29 23:11       ` Greg Kroah-Hartman
     [not found]         ` <20141029231106.GB16548-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2014-10-29 23:12           ` Greg Kroah-Hartman
2014-10-29 23:24           ` Jiri Kosina
     [not found]             ` <alpine.LRH.2.00.1410300019570.11562-1ReQVI26iDCaZKY3DrU6dA@public.gmane.org>
2014-10-29 23:26               ` Jiri Kosina
     [not found]                 ` <alpine.LRH.2.00.1410300024530.11562-1ReQVI26iDCaZKY3DrU6dA@public.gmane.org>
2014-10-29 23:34                   ` Greg Kroah-Hartman
2014-10-29 23:40               ` Greg Kroah-Hartman
2014-10-29 23:55                 ` Andy Lutomirski
2014-10-30 11:52                   ` Tom Gundersen
     [not found]                     ` <CAG-2HqX9RUQHiF1U_CXiDVVLS-7aUOQdYn7EVNSMZNdbe38cTA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30 12:28                       ` Simon McVittie
2014-10-30 13:59                     ` Andy Lutomirski
2014-10-30 20:28                       ` Alex Elsayed
2014-10-30  9:51                 ` Karol Lewandowski
     [not found]                   ` <54520A21.20404-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-10-30 10:44                     ` Karol Lewandowski
     [not found]                       ` <54521697.1030900-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-10-30 14:47                         ` Greg Kroah-Hartman
     [not found]                           ` <20141030144709.GA19721-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2014-10-30 19:55                             ` Karol Lewandowski
     [not found]                               ` <545297CC.6020306-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-10-30 20:24                                 ` Greg Kroah-Hartman
2014-10-31 11:15                                   ` Karol Lewandowski
2014-10-30 23:13                                 ` One Thousand Gnomes
     [not found]                                   ` <20141030231310.0b65b762-mUKnrFFms3BCCTY1wZZT65JpZx93mCW/@public.gmane.org>
2014-10-31 10:58                                     ` Karol Lewandowski
2014-10-30 23:39                               ` Paul Moore
2014-10-31 14:21                                 ` Karol Lewandowski
2014-10-31 16:36                                   ` [RFC PATCH 0/5] kdbus: add support for lsm Karol Lewandowski
2014-10-31 16:36                                     ` [PATCH 1/5] kdbus: extend structures with security pointer " Karol Lewandowski
     [not found]                                       ` <1414773397-26490-2-git-send-email-k.lewandowsk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-11-17  1:47                                         ` Karol Lewandowski
2014-11-17 18:37                                           ` Greg KH
2014-10-31 16:36                                     ` [PATCH 2/5] security: export security_file_receive for modules Karol Lewandowski
2014-10-31 16:36                                     ` [PATCH 3/5] kdbus: check if lsm permits installing received fds Karol Lewandowski
     [not found]                                     ` <1414773397-26490-1-git-send-email-k.lewandowsk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-10-31 16:36                                       ` [PATCH 4/5] security: introduce lsm hooks for kdbus Karol Lewandowski
2014-10-31 16:36                                       ` [PATCH 5/5] kdbus: make use of new lsm hooks Karol Lewandowski
2014-10-31 17:19                                       ` [PATCH 3/5] kdbus: check if lsm permits installing received fds Karol Lewandowski
2014-11-07 18:01                                     ` [RFC PATCH 0/5] kdbus: add support for lsm Greg KH
     [not found]                                       ` <20141107180120.GA15387-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2014-11-09  0:07                                         ` Karol Lewandowski
2014-11-02  1:21       ` [PATCH 00/12] Add kdbus implementation Greg Kroah-Hartman
     [not found]         ` <20141102012130.GA9335-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2014-11-03 14:38           ` One Thousand Gnomes
2014-10-30  8:33   ` Arnd Bergmann
2014-10-30 16:17     ` Greg Kroah-Hartman
  -- strict thread matches above, loose matches on Subject: below --
2014-11-21  5:02 [PATCH v2 00/13] " Greg Kroah-Hartman
2014-11-21  5:02 ` kdbus: add code to gather metadata Greg Kroah-Hartman
     [not found]   ` <1416546149-24799-8-git-send-email-gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2014-11-21 19:50     ` Andy Lutomirski
     [not found]       ` <546F977B.7040500-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
2014-12-01 13:50         ` Daniel Mack
2014-12-01 14:46           ` Andy Lutomirski

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