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Message-ID: <559FFDDF.2090302@schaufler-ca.com>
Date: Fri, 10 Jul 2015 10:16:15 -0700
From: Casey Schaufler <casey@schaufler-ca.com>
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To: David Herrmann <dh.herrmann@gmail.com>
CC: Stephen Smalley <sds@tycho.nsa.gov>, Greg KH <gregkh@linuxfoundation.org>,
        Daniel Mack <daniel@zonque.org>, Djalal Harouni <tixxdz@opendz.org>,
        lkml <linux-kernel@vger.kernel.org>,
        LSM <linux-security-module@vger.kernel.org>,
        Paul Osmialowski <p.osmialowsk@samsung.com>,
        Paul Moore <paul@paul-moore.com>
Subject: Re: kdbus: credential faking
References: <559EBCC0.7040604@tycho.nsa.gov>	<CANq1E4QH37+H3cbauN8LDRxp+Rsmtcn6CkLYCiV7XQrhm=qP9Q@mail.gmail.com>	<559FC7DD.8060507@tycho.nsa.gov>	<CANq1E4TaE6EK1iEGLq_Zhu6=z52VZx7sPFc4TVc1vt1F3pShcA@mail.gmail.com>	<559FEBF2.1040908@schaufler-ca.com> <CANq1E4Sdpb81PW9Ju+bnRjtZ=9HkGwGse-gstx1SjaEzmWiT-w@mail.gmail.com>
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On 7/10/2015 9:26 AM, David Herrmann wrote:
> Hi
>
> On Fri, Jul 10, 2015 at 5:59 PM, Casey Schaufler <casey@schaufler-ca.com> wrote:
> [...]
>>                There are so many ways uids are being (miss/ab)used
>> on Linux systems these days that the idea of trusting a bus just
>> because its non-root uid is listed in a table somewhere (or worse,
>> coded in an API) is asking for exploits.
> Please elaborate on these possible exploits. I'd also like to hear,
> whether the same applies to the already used '/run/user/<uid>/bus',
> which follows nearly the same model.

Sorry, I'm not the exploit generator guy. If I where, I would
point out that the application expecting the uid to identify
a person is going to behave incorrectly on the system that uses
the uid to identify an application. I never said that I liked
/run/user/<uid>/bus. Come to think of it, I never said I like
dbus, either.


>
> Thanks
> David
>

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