From: Sasha Levin <sashal@kernel.org>
To: Mimi Zohar <zohar@linux.ibm.com>
Cc: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
linux-integrity@vger.kernel.org,
Matthew Garrett <mjg59@google.com>,
jamorris@linux.microsoft.com, kgoldman@us.ibm.com, "Wiseman,
Monty (GE Global Research, US)" <monty.wiseman@ge.com>,
Roberto Sassu <roberto.sassu@huawei.com>,
Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH 0/1] KEYS: Measure keys in trusted keyring
Date: Thu, 19 Sep 2019 09:18:51 -0400 [thread overview]
Message-ID: <20190919131851.GA8171@sasha-vm> (raw)
In-Reply-To: <1568035881.4614.347.camel@linux.ibm.com>
On Mon, Sep 09, 2019 at 09:31:21AM -0400, Mimi Zohar wrote:
>On Tue, 2019-09-03 at 08:54 -0700, Lakshmi Ramasubramanian wrote:
>> On 8/30/19 11:41 AM, Mimi Zohar wrote:
>>
>> > No, the measurement list ima-sig template record contains both the
>> > file hash and signature. There's no need to maintain a white list of
>> > either the file hashes or signed hashes. All that is needed is the
>> > set of permitted public keys (eg. keys on the trusted IMA keyring).
>>
>> You are right - Thanks for the info.
>>
>> > Even though on the local system, files signed by the system owner
>> > would be permitted, the attestation server would be able to control
>> > access to whatever service. For example, Trusted Network Connect
>> > (TNC) could control network access. By measuring the keys on the
>> > builtin/secondary keyrings, that control is not based on who signed
>> > the software package, but based on who signed the certificate of the
>> > key that signed the software package. My concern is how this level of
>> > indirection could be abused.
>> Since the signer of certificate of the key that signed the software
>> package changes much less frequently compared to the certificate of the
>> key used to sign the software package, the operational overhead on the
>> server side is significantly reduced.
>>
>> I understand there is another level of indirection here. But I am also
>> not clear how this can be abused.
>
>The remote attestation server could gate any service based on the
>certificate signer. The first gated service, based on this feature,
>will probably be network access (eg. TNC). If/when this feature is
>upstreamed, every company, including financial institutes,
I'm not sure why upstreaming this code will matter for those entities
you're concerned about. Any entity that provides a signed kernel image
is very well capable of including out of tree patches in that image.
>organizations, and governments will become THE certificate signer for
>their organization, in order to limit access to their network and
>systems. Once that happens, how long will it be until the same
>feature will be abused and used to limit the individual's ability to
>pick and choose which applications may run on their systems.[1]
We do not restrict end use of the kernel; this is one of the main
reasons that the kernel is licensed under GPLv2 rather than GPLv3.
Please see https://lwn.net/Articles/200422/ .
We'd love to work with you on the technical aspects of this code to make
it acceptable to the IMA maintainers, but this work can't just be NACKed
based on a perceived end use of it.
--
Thanks,
Sasha
next prev parent reply other threads:[~2019-09-19 13:18 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-28 0:27 [PATCH 0/1] KEYS: Measure keys in trusted keyring Lakshmi Ramasubramanian
2019-08-28 0:27 ` [PATCH 1/1] " Lakshmi Ramasubramanian
2019-09-02 22:04 ` Mimi Zohar
2019-08-29 1:11 ` [PATCH 0/1] " Mimi Zohar
2019-08-30 2:43 ` Lakshmi Ramasubramanian
2019-08-30 18:41 ` Mimi Zohar
2019-09-03 15:54 ` Lakshmi Ramasubramanian
2019-09-09 13:31 ` Mimi Zohar
2019-09-09 21:34 ` James Morris
2019-09-19 13:18 ` Sasha Levin [this message]
2019-09-19 17:12 ` Mimi Zohar
2019-10-04 19:29 ` Lakshmi Ramasubramanian
2019-10-04 19:57 ` Mimi Zohar
2019-10-04 20:10 ` Lakshmi Ramasubramanian
2019-10-04 21:58 ` Mimi Zohar
2019-10-05 0:10 ` Lakshmi Ramasubramanian
2019-10-06 13:17 ` Mimi Zohar
2019-10-07 15:03 ` Lakshmi Ramasubramanian
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190919131851.GA8171@sasha-vm \
--to=sashal@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=jamorris@linux.microsoft.com \
--cc=kgoldman@us.ibm.com \
--cc=linux-integrity@vger.kernel.org \
--cc=mjg59@google.com \
--cc=monty.wiseman@ge.com \
--cc=nramas@linux.microsoft.com \
--cc=roberto.sassu@huawei.com \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).