Re: [PATCH] Documentation/admin-guide: Embargoed hardware security issues

[Greg Kroah-Hartman]

On Thu, Jul 25, 2019 at 03:13:02PM -0600, Jonathan Corbet wrote:
> On Thu, 25 Jul 2019 15:01:13 +0200
> Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> 
> > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > 
> > To address the requirements of embargoed hardware issues, like Meltdown,
> > Spectre, L1TF, etc. it is necessary to define and document a process for
> > handling embargoed hardware security issues.
> > 
> > Following the discussion at the maintainer summit 2018 in Edinburgh
> > (https://lwn.net/Articles/769417/) the volunteered people have worked
> > out a process and a Memorandum of Understanding.  The latter addresses
> > the fact that the Linux kernel community cannot sign NDAs for various
> > reasons.
> > 
> 
> [...]
> 
> >  Documentation/admin-guide/embargoed-hardware-issues.rst |  281 ++++++++++++++++
> >  Documentation/admin-guide/index.rst                     |    1 
> >  2 files changed, 282 insertions(+)
> 
> So I would argue that the admin guide (which is aimed at sysadmins) is the
> wrong place for this document.  It's process information and is best placed
> in the process manual (Documentation/process) IMO.  (Yes, I know
> security-bugs.rst is in the admin guide; I remember there was a discussion
> at the time and it ended up there, but I'm not really sure that's right
> either).

Ok, will move it to the process directory.

> > Note, this document has gone through numerous reviews by a number of
> > kernel developers, developers at some of the Linux distros, as well as
> > all of the lawyers from almost all open source-related companies.  It's
> > been sitting on my local drive with no comments for a few months now,
> > and it's about time to get this out and merged properly.
> > 
> > If anyone has any final comments, please let me know.
> 
> I do think it could benefit from a pass for basic language issues; I can do
> that if such an effort would be welcome.

It would be!

> > If anyone from any company listed below wishes to add their name to the
> > document, please send a follow-on patch and I will be glad to add it to
> > the series.  I had a number of "I'll sign up" type comments from
> > different people, but I want something with a "s-o-b" to keep people on
> > the hook for this, so I did not add their name to the file without that.
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > 
> > 
> > --- /dev/null
> > +++ b/Documentation/admin-guide/embargoed-hardware-issues.rst
> > @@ -0,0 +1,281 @@
> > +.. _embargoedhardwareissues:
> 
> This label isn't used anywhere.

Odd, ok, dropped.

> 
> > +Embargoed hardware issues
> > +=========================
> > +
> > +Scope
> > +-----
> > +
> > +Hardware issues which result in security problems are a different category
> > +of security bugs than pure software bugs which  only affect the Linux
> > +kernel.
> > +
> > +Hardware issues like Meltdown, Spectre, L1TF etc. must be treated
> > +differently because they usually affect all Operating Systems (âOSâ) and
> 
> Somebody may well complain about the "smart quotes" here; non-ascii stuff
> has led to unhappiness in the past.

Now fixed, thanks.

> > +therefore need coordination across different OS vendors, distributions,
> > +hardware vendors and other parties. For some of the issues, software
> > +mitigations can depend on microcode or firmware updates, which need further
> > +coordination.
> > +
> > +.. _Contact:
> > +
> > +Contact
> > +-------
> > +
> > +The Linux kernel hardware security team is separate from the regular Linux
> > +kernel security team.
> > +
> > +The team is only handling the coordination of embargoed hardware security
> 
> s/is only handling/only handles/

Fixed.

> > +issues. Reports of pure software security bugs in the Linux kernel are not
> > +handled by this team and the reporter will be guided to contact the regular
> > +Linux kernel security team (:ref:`Documentation/admin-guide/
> > +<securitybugs>`) instead.
> > +
> > +The team can be contacted by email at <hardware-security@xxxxxxxxxx>. This
> > +is a private list of security officers who will help you to coordinate an
> > +issue according to our documented process.
> > +
> > +The list is encrypted and email to the list can be sent by either PGP or
> > +S/MIME encrypted and must be signed with the reporter's PGP key or S/MIME
> > +certificate. The list's PGP key and S/MIME certificate are available from
> > +https://www.kernel.org/....
> 
> Somebody needs to fill in some dots there...:)

Will work on that...

> > +While hardware security issues are often handled by the affected hardware
> > +vendor, we welcome contact from researchers or individuals who identified a
> 
> who *have* identified

fixed.

> > +potential hardware flaw.
> > +
> > +Hardware security officers
> > +^^^^^^^^^^^^^^^^^^^^^^^^^^
> > +
> > +The current team of hardware security officers:
> > +
> > +  - Linus Torvalds (Linux Foundation Fellow)
> > +  - Greg Kroah-Hartman (Linux Foundation Fellow)
> > +  - Thomas Gleixner (Linux Foundation Fellow)
> > +
> > +Operation of mailing-lists
> > +^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> I would de-hyphenate "mailing list" throughout.  But that's me.

I'll let the original author have it his way :)

> > +The encrypted mailing-lists which are used in our process are hosted on
> > +Linux Foundation's IT infrastructure. By providing this service Linux
> > +Foundation's director of IT Infrastructure security technically has the
> > +ability to access the embargoed information, but is obliged to
> > +confidentiality by his employment contract. Linux Foundation's director of
> > +IT Infrastructure security is also responsible for the kernel.org
> > +infrastructure.
> > +
> > +The Linux Foundation's current director of IT Infrastructure security is
> > +Konstantin Ryabitsev.
> > +
> > +
> > +Non-disclosure agreements
> > +-------------------------
> > +
> > +The Linux kernel hardware security team is not a formal body and therefore
> > +unable to enter into any non-disclosure agreements.  The kernel community
> > +is aware of the sensitive nature of such issues and offers a Memorandum of
> > +Understanding instead.
> > +
> > +
> > +Memorandum of Understanding
> > +---------------------------
> > +
> > +The Linux kernel community has a deep understanding of the requirement to
> > +keep hardware security issues under embargo for coordination between
> > +different OS vendors, distributors, hardware vendors and other parties.
> > +
> > +The Linux kernel community has successfully handled hardware security
> > +issues in the past and has the necessary mechanisms in place to allow
> > +community compliant development under embargo restrictions.
> > +
> > +The Linux kernel community has a dedicated hardware security team for
> > +initial contact, which oversees the process of handling such issues under
> > +embargo rules.
> > +
> > +The hardware security team identifies the developers (domain experts) which
> > +form the initial response team for a particular issue. The initial response
> 
> s/which form/who will form/

fixed.

> > +team can bring in further developers (domain experts) to address the issue
> > +in the best technical way.
> 
> Does the reporter get any say in who can be in this group?  That should
> probably be made explicit either way.

That is discussed later in the document, and the reporter can offer up
people, but that's about it.  It's up to us running the list to be the
ones in charge of this, and that's one of the main reasons this document
exists.

I'll leave the wording as-is for now, given all of the lawyers who have
already agreed with it.  If we find people objecting to how it all is
written now in the future, we can revisit it.

> > +All involved developers pledge to adhere to the embargo rules and to keep
> > +the received information confidential. Violation of the pledge will lead to
> > +immediate exclusion from the current issue and removal from all related
> > +mailing-lists. In addition, the hardware security team will also exclude
> > +the offender from future issues. The impact of this consequence is a highly
> > +effective deterrent in our community. In case a violation happens the
> > +hardware security team will inform the involved parties immediately. If you
> > +or anyone becomes aware of a potential violation, please report it
> > +immediately to the Hardware security officers.
> > +
> > +
> > +Process
> > +^^^^^^^
> > +
> > +Due to the globally distributed nature of Linux kernel development, face to
> > +face meetings are almost impossible to address hardware security issues.
> 
> face-to-face

fixed.

> > +Phone conferences are hard to coordinate due to time zones and other
> > +factors and should be only used when absolutely necessary. Encrypted email
> > +has been proven to be the most effective and secure communication method
> > +for these types of issues.
> > +
> > +Start of Disclosure
> > +"""""""""""""""""""
> > +
> > +Disclosure starts by contacting the Linux kernel hardware security team by
> > +email. This initial contact should contain a description of the problem and
> > +a list of any known affected hardware. If your organization builds or
> > +distributes the affected hardware, we encourage you to also consider what
> > +other hardware could be affected.
> > +
> > +The hardware security team will provide a per incident specific encrypted
> 
> s/per incident specific/incident-specific/

Fixed.  And changed /a/ to /an/

> > +mailing-list which will be used for initial discussion with the reporter,
> > +further disclosure and coordination.
> > +
> > +The hardware security team will provide the disclosing party a list of
> > +developers (domain experts) who should be informed initially about the
> > +issue after confirming with the developers  that they will adhere to this
> > +Memorandum of Understanding and the documented process. These developers
> > +form the initial response team and will be responsible for handling the
> > +issue after initial contact. The hardware security team is supporting the
> > +response team, but is not necessarily involved in the mitigation
> > +development process.
> 
> Again, "should be informed" is conditional, suggesting that the reporter
> might have some sort of veto power.  But the actual policy is not clear.

Embrace the grey, it is much better here :)

> > +While individual developers might be covered by a non-disclosure agreement
> > +via their employer, they cannot enter individual non-disclosure agreements
> > +in their role as Linux kernel developers. They will, however, adhere to
> > +this documented process and the Memorandum of Understanding.
> 
> They will *agree to* adhere ...  We expect that actual adherence will be
> the case but there is no way (even if an NDA were involved) to guarantee
> that.

True, fixed up now.

> > +Disclosure
> > +""""""""""
> > +
> > +The disclosing party provides detailed information to the initial response
> > +team via the specific encrypted mailing-list.
> > +
> > +From our experience the technical documentation of these issues is usually
> > +a sufficient starting point and further technical clarification is best
> > +done via email.
> > +
> > +Mitigation development
> > +""""""""""""""""""""""
> > +
> > +The initial response team sets up an encrypted mailing-list or repurposes
> > +an existing one if appropriate. The disclosing party should provide a list
> > +of contacts for all other parties who have already been, or should be
> > +informed about the issue. The response team contacts these parties so they
> > +can name experts who should be subscribed to the mailing-list.
> > +
> > +Using a mailing-list is close to the normal Linux development process and
> > +has been successfully used in developing mitigations for various hardware
> > +security issues in the past.
> > +
> > +The mailing-list operates in the same way as normal Linux development.
> > +Patches are posted, discussed and reviewed and if agreed on applied to a
> > +non-public git repository which is only accessible to the participating
> > +developers via a secure connection. The repository contains the main
> > +development branch against the mainline kernel and backport branches for
> > +stable kernel versions as necessary.
> 
> Do we want to envision a KPTI-like situation where the mitigation can be
> developed publicly?  Or perhaps just handle any such case if and when it
> ever arises?

We can handle such cases if and when it arises.  And who's to say it
already hasn't?  :)

> > +The initial response team will identify further experts from the Linux
> > +kernel developer community as needed and inform the disclosing party about
> > +their participation. Bringing in experts can happen at any time of the
> > +development process and often needs to be handled in a timely manner.
> > +
> > +Coordinated release
> > +"""""""""""""""""""
> > +
> > +The involved parties will negotiate the date and time where the embargo
> > +ends. At that point the prepared mitigations are integrated into the
> > +relevant kernel trees and published.
> > +
> > +While we understand that hardware security issues need coordinated embargo
> > +time, the embargo time should be constrained to the minimum time which is
> > +required for all involved parties to develop, test and prepare the
> > +mitigations. Extending embargo time artificially to meet conference talk
> > +dates or other non-technical reasons is creating more work and burden for
> > +the involved developers and response teams as the patches need to be kept
> > +up to date in order to follow the ongoing upstream kernel development,
> > +which might create conflicting changes.
> > +
> > +CVE assignment
> > +""""""""""""""
> > +
> > +Neither the hardware security team nor the initial response team assign
> > +CVEs, nor are CVEs required for the development process. If CVEs are
> > +provided by the disclosing party they can be used for documentation
> > +purposes.
> > +
> > +Process ambassadors
> > +-------------------
> > +
> > +For assistance with this process we have established ambassadors in various
> > +organizations, who can answer questions about or provide guidance on the
> > +reporting process and further handling. Ambassadors are not involved in the
> > +disclosure of a particular issue, unless requested by a response team or by
> > +an involved disclosed party. The current ambassadors list:
> > +
> > +  ============== ========================================================
> > +  ARM
> > +  AMD
> > +  IBM
> > +  Intel
> > +  Qualcomm
> > +
> > +  Microsoft
> > +  VMware
> > +  XEN
> > +
> > +  Canonical
> > +  Debian
> > +  Oracle
> > +  Redhat
> > +  Suse           Jiri Kosina <jkosina@xxxxxxxx>
> > +
> > +  Amazon
> > +  Google
> > +  ============== ========================================================
> 
> Having companies without names seems a little weird.  Unless perhaps you
> have people teed up to add their names in follow-on patches?

Jiri posted an update with more names.

The blank lines are there for where we want names.  I have a bunch of
people who have agreed, but I want them sending add-on patches for the
document, with their s-o-b on it, so that everyone "knows" they really
agree with this, and that someone didn't just add their name to the
document without them realizing.

> > +If you want your organization to be added to the ambassadors list, please
> > +contact the hardware security team. The nominated ambassador has to
> > +understand and support our process fully and is ideally well connected in
> > +the Linux kernel community.
> > +
> > +Encrypted mailing-lists
> > +-----------------------
> > +
> > +We use encrypted mailing-lists for communication. The operating principle
> > +of these lists is that email sent to the list is encrypted either with the
> > +list's PGP key or with the list's S/MIME certificate. The mailing-list
> > +software decrypts the email and re-encrypts it individually for each
> > +subscriber with the subscriber's PGP key or S/MIME certificate. Details
> > +about the mailing-list software and the setup which is used to ensure the
> > +security of the lists and protection of the data can be found here:
> > +https://www.kernel.org/....
> 
> That URL is also in need of completion.

Yeah, we will work on that next...

> 
> The topic of encrypted mailing lists is visited several times in this
> document; I wonder if that could be coalesced somehow?

Edits are welcome :)

> > +List keys
> > +^^^^^^^^^
> > +
> > +For initial contact see :ref:`Contact`. For incident specific mailing-lists
> > +the key and S/MIME certificate are conveyed to the subscribers by email
> > +sent from the specific list.
> > +
> > +Subscription to incident specific lists
> > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > +
> > +Subscription is handled by the response teams. Disclosed parties who want
> > +to participate in the communication send a list of potential subscribers to
> > +the response team so the response team can validate subscription requests.
> > +
> > +Each subscriber needs to send a subscription request to the response team
> > +by email. The email must be signed with the subscriber's PGP key or S/MIME
> > +certificate. If a PGP key is used, it must be available from a public key
> > +server and is ideally connected to the Linux kernel's PGP web of trust. See
> > +also: https://www.kernel.org/signature.html.
> 
> The "public key server" thing isn't working quite as well as it was; does
> this requirement need to be revisited?

We have a private web right now, and it's the best we have at the
moment.  So until we get something else, let's stick with it.

Many thanks for the edits, I'll send out a new version soon.

greg k-h