.. _embargoed_hardware_issues:
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Embargoed hardware issues
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=========================
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Scope
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-----
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Hardware issues which result in security problems are a different category
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of security bugs than pure software bugs which only affect the Linux
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kernel.
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Hardware issues like Meltdown, Spectre, L1TF etc. must be treated
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differently because they usually affect all Operating Systems ("OS") and
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therefore need coordination across different OS vendors, distributions,
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hardware vendors and other parties. For some of the issues, software
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mitigations can depend on microcode or firmware updates, which need further
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coordination.
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.. _Contact:
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Contact
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-------
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The Linux kernel hardware security team is separate from the regular Linux
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kernel security team.
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The team only handles the coordination of embargoed hardware security
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issues. Reports of pure software security bugs in the Linux kernel are not
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handled by this team and the reporter will be guided to contact the regular
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Linux kernel security team (:ref:`Documentation/admin-guide/
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<securitybugs>`) instead.
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The team can be contacted by email at <hardware-security@kernel.org>. This
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is a private list of security officers who will help you to coordinate an
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issue according to our documented process.
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The list is encrypted and email to the list can be sent by either PGP or
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S/MIME encrypted and must be signed with the reporter's PGP key or S/MIME
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certificate. The list's PGP key and S/MIME certificate are available from
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the following URLs:
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- PGP: https://www.kernel.org/static/files/hardware-security.asc
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- S/MIME: https://www.kernel.org/static/files/hardware-security.crt
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While hardware security issues are often handled by the affected hardware
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vendor, we welcome contact from researchers or individuals who have
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identified a potential hardware flaw.
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Hardware security officers
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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The current team of hardware security officers:
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- Linus Torvalds (Linux Foundation Fellow)
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- Greg Kroah-Hartman (Linux Foundation Fellow)
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- Thomas Gleixner (Linux Foundation Fellow)
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Operation of mailing-lists
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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The encrypted mailing-lists which are used in our process are hosted on
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Linux Foundation's IT infrastructure. By providing this service, members
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of Linux Foundation's IT operations personnel technically have the
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ability to access the embargoed information, but are obliged to
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confidentiality by their employment contract. Linux Foundation IT
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personnel are also responsible for operating and managing the rest of
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kernel.org infrastructure.
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The Linux Foundation's current director of IT Project infrastructure is
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Konstantin Ryabitsev.
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Non-disclosure agreements
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-------------------------
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The Linux kernel hardware security team is not a formal body and therefore
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unable to enter into any non-disclosure agreements. The kernel community
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is aware of the sensitive nature of such issues and offers a Memorandum of
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Understanding instead.
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Memorandum of Understanding
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---------------------------
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The Linux kernel community has a deep understanding of the requirement to
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keep hardware security issues under embargo for coordination between
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different OS vendors, distributors, hardware vendors and other parties.
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The Linux kernel community has successfully handled hardware security
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issues in the past and has the necessary mechanisms in place to allow
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community compliant development under embargo restrictions.
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The Linux kernel community has a dedicated hardware security team for
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initial contact, which oversees the process of handling such issues under
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embargo rules.
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The hardware security team identifies the developers (domain experts) who
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will form the initial response team for a particular issue. The initial
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response team can bring in further developers (domain experts) to address
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the issue in the best technical way.
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All involved developers pledge to adhere to the embargo rules and to keep
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the received information confidential. Violation of the pledge will lead to
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immediate exclusion from the current issue and removal from all related
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mailing-lists. In addition, the hardware security team will also exclude
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the offender from future issues. The impact of this consequence is a highly
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effective deterrent in our community. In case a violation happens the
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hardware security team will inform the involved parties immediately. If you
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or anyone becomes aware of a potential violation, please report it
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immediately to the Hardware security officers.
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Process
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^^^^^^^
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Due to the globally distributed nature of Linux kernel development,
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face-to-face meetings are almost impossible to address hardware security
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issues. Phone conferences are hard to coordinate due to time zones and
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other factors and should be only used when absolutely necessary. Encrypted
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email has been proven to be the most effective and secure communication
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method for these types of issues.
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Start of Disclosure
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"""""""""""""""""""
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Disclosure starts by contacting the Linux kernel hardware security team by
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email. This initial contact should contain a description of the problem and
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a list of any known affected hardware. If your organization builds or
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distributes the affected hardware, we encourage you to also consider what
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other hardware could be affected.
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The hardware security team will provide an incident-specific encrypted
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mailing-list which will be used for initial discussion with the reporter,
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further disclosure and coordination.
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The hardware security team will provide the disclosing party a list of
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developers (domain experts) who should be informed initially about the
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issue after confirming with the developers that they will adhere to this
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Memorandum of Understanding and the documented process. These developers
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form the initial response team and will be responsible for handling the
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issue after initial contact. The hardware security team is supporting the
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response team, but is not necessarily involved in the mitigation
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development process.
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While individual developers might be covered by a non-disclosure agreement
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via their employer, they cannot enter individual non-disclosure agreements
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in their role as Linux kernel developers. They will, however, agree to
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adhere to this documented process and the Memorandum of Understanding.
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The disclosing party should provide a list of contacts for all other
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entities who have already been, or should be, informed about the issue.
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This serves several purposes:
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- The list of disclosed entities allows communication accross the
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industry, e.g. other OS vendors, HW vendors, etc.
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- The disclosed entities can be contacted to name experts who should
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participate in the mitigation development.
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- If an expert which is required to handle an issue is employed by an
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listed entity or member of an listed entity, then the response teams can
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request the disclosure of that expert from that entity. This ensures
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that the expert is also part of the entity's response team.
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Disclosure
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""""""""""
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The disclosing party provides detailed information to the initial response
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team via the specific encrypted mailing-list.
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From our experience the technical documentation of these issues is usually
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a sufficient starting point and further technical clarification is best
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done via email.
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Mitigation development
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""""""""""""""""""""""
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The initial response team sets up an encrypted mailing-list or repurposes
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an existing one if appropriate.
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Using a mailing-list is close to the normal Linux development process and
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has been successfully used in developing mitigations for various hardware
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security issues in the past.
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The mailing-list operates in the same way as normal Linux development.
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Patches are posted, discussed and reviewed and if agreed on applied to a
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non-public git repository which is only accessible to the participating
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developers via a secure connection. The repository contains the main
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development branch against the mainline kernel and backport branches for
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stable kernel versions as necessary.
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The initial response team will identify further experts from the Linux
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kernel developer community as needed. Bringing in experts can happen at any
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time of the development process and needs to be handled in a timely manner.
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If an expert is employed by or member of an entity on the disclosure list
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provided by the disclosing party, then participation will be requested from
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the relevant entity.
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If not, then the disclosing party will be informed about the experts
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participation. The experts are covered by the Memorandum of Understanding
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and the disclosing party is requested to acknowledge the participation. In
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case that the disclosing party has a compelling reason to object, then this
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objection has to be raised within five work days and resolved with the
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incident team immediately. If the disclosing party does not react within
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five work days this is taken as silent acknowledgement.
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After acknowledgement or resolution of an objection the expert is disclosed
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by the incident team and brought into the development process.
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Coordinated release
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"""""""""""""""""""
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The involved parties will negotiate the date and time where the embargo
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ends. At that point the prepared mitigations are integrated into the
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relevant kernel trees and published.
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While we understand that hardware security issues need coordinated embargo
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time, the embargo time should be constrained to the minimum time which is
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required for all involved parties to develop, test and prepare the
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mitigations. Extending embargo time artificially to meet conference talk
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dates or other non-technical reasons is creating more work and burden for
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the involved developers and response teams as the patches need to be kept
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up to date in order to follow the ongoing upstream kernel development,
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which might create conflicting changes.
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CVE assignment
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""""""""""""""
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Neither the hardware security team nor the initial response team assign
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CVEs, nor are CVEs required for the development process. If CVEs are
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provided by the disclosing party they can be used for documentation
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purposes.
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Process ambassadors
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-------------------
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For assistance with this process we have established ambassadors in various
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organizations, who can answer questions about or provide guidance on the
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reporting process and further handling. Ambassadors are not involved in the
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disclosure of a particular issue, unless requested by a response team or by
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an involved disclosed party. The current ambassadors list:
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============= ========================================================
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ARM Grant Likely <grant.likely@arm.com>
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AMD Tom Lendacky <tom.lendacky@amd.com>
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IBM Z Christian Borntraeger <borntraeger@de.ibm.com>
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IBM Power Anton Blanchard <anton@linux.ibm.com>
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Intel Tony Luck <tony.luck@intel.com>
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Qualcomm Trilok Soni <tsoni@codeaurora.org>
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Microsoft James Morris <jamorris@linux.microsoft.com>
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VMware
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Xen Andrew Cooper <andrew.cooper3@citrix.com>
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Canonical John Johansen <john.johansen@canonical.com>
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Debian Ben Hutchings <ben@decadent.org.uk>
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Oracle Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Red Hat Josh Poimboeuf <jpoimboe@redhat.com>
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SUSE Jiri Kosina <jkosina@suse.cz>
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Amazon
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Google Kees Cook <keescook@chromium.org>
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============= ========================================================
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If you want your organization to be added to the ambassadors list, please
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contact the hardware security team. The nominated ambassador has to
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understand and support our process fully and is ideally well connected in
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the Linux kernel community.
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Encrypted mailing-lists
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-----------------------
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We use encrypted mailing-lists for communication. The operating principle
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of these lists is that email sent to the list is encrypted either with the
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list's PGP key or with the list's S/MIME certificate. The mailing-list
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software decrypts the email and re-encrypts it individually for each
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subscriber with the subscriber's PGP key or S/MIME certificate. Details
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about the mailing-list software and the setup which is used to ensure the
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security of the lists and protection of the data can be found here:
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https://korg.wiki.kernel.org/userdoc/remail.
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List keys
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^^^^^^^^^
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For initial contact see :ref:`Contact`. For incident specific mailing-lists
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the key and S/MIME certificate are conveyed to the subscribers by email
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sent from the specific list.
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Subscription to incident specific lists
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Subscription is handled by the response teams. Disclosed parties who want
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to participate in the communication send a list of potential subscribers to
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the response team so the response team can validate subscription requests.
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Each subscriber needs to send a subscription request to the response team
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by email. The email must be signed with the subscriber's PGP key or S/MIME
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certificate. If a PGP key is used, it must be available from a public key
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server and is ideally connected to the Linux kernel's PGP web of trust. See
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also: https://www.kernel.org/signature.html.
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The response team verifies that the subscriber request is valid and adds
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the subscriber to the list. After subscription the subscriber will receive
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email from the mailing-list which is signed either with the list's PGP key
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or the list's S/MIME certificate. The subscriber's email client can extract
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the PGP key or the S/MIME certificate from the signature so the subscriber
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can send encrypted email to the list.
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