linux/Documentation/admin-guide/security-bugs.rst

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.. _securitybugs:
Security bugs
=============
Linux kernel developers take security very seriously. As such, we'd
like to know when a security bug is found so that it can be fixed and
disclosed as quickly as possible. Please report security bugs to the
Linux kernel security team.
Contact
-------
The Linux kernel security team can be contacted by email at
<security@kernel.org>. This is a private list of security officers
who will help verify the bug report and develop and release a fix.
If you already have a fix, please include it with your report, as
that can speed up the process considerably. It is possible that the
security team will bring in extra help from area maintainers to
understand and fix the security vulnerability.
As it is with any bug, the more information provided the easier it
will be to diagnose and fix. Please review the procedure outlined in
:doc:`reporting-bugs` if you are unclear about what
information is helpful. Any exploit code is very helpful and will not
be released without consent from the reporter unless it has already been
made public.
Please send plain text emails without attachments where possible.
It is much harder to have a context-quoted discussion about a complex
issue if all the details are hidden away in attachments. Think of it like a
:doc:`regular patch submission <../process/submitting-patches>`
(even if you don't have a patch yet): describe the problem and impact, list
reproduction steps, and follow it with a proposed fix, all in plain text.
Disclosure and embargoed information
------------------------------------
The security list is not a disclosure channel. For that, see Coordination
below.
Documentation/security-bugs: Postpone fix publication in exceptional cases At the request of the reporter, the Linux kernel security team offers to postpone the publishing of a fix for up to 5 business days from the date of a report. While it is generally undesirable to keep a fix private after it has been developed, this short window is intended to allow distributions to package the fix into their kernel builds and permits early inclusion of the security team in the case of a co-ordinated disclosure with other parties. Unfortunately, discussions with major Linux distributions and cloud providers has revealed that 5 business days is not sufficient to achieve either of these two goals. As an example, cloud providers need to roll out KVM security fixes to a global fleet of hosts with sufficient early ramp-up and monitoring. An end-to-end timeline of less than two weeks dramatically cuts into the amount of early validation and increases the chance of guest-visible regressions. The consequence of this timeline mismatch is that security issues are commonly fixed without the involvement of the Linux kernel security team and are instead analysed and addressed by an ad-hoc group of developers across companies contributing to Linux. In some cases, mainline (and therefore the official stable kernels) can be left to languish for extended periods of time. This undermines the Linux kernel security process and puts upstream developers in a difficult position should they find themselves involved with an undisclosed security problem that they are unable to report due to restrictions from their employer. To accommodate the needs of these users of the Linux kernel and encourage them to engage with the Linux security team when security issues are first uncovered, extend the maximum period for which fixes may be delayed to 7 calendar days, or 14 calendar days in exceptional cases, where the logistics of QA and large scale rollouts specifically need to be accommodated. This brings parity with the linux-distros@ maximum embargo period of 14 calendar days. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Amit Shah <aams@amazon.com> Cc: Laura Abbott <labbott@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Co-developed-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-19 11:07:18 +00:00
Once a robust fix has been developed, the release process starts. Fixes
for publicly known bugs are released immediately.
Although our preference is to release fixes for publicly undisclosed bugs
as soon as they become available, this may be postponed at the request of
the reporter or an affected party for up to 7 calendar days from the start
of the release process, with an exceptional extension to 14 calendar days
if it is agreed that the criticality of the bug requires more time. The
only valid reason for deferring the publication of a fix is to accommodate
the logistics of QA and large scale rollouts which require release
coordination.
While embargoed information may be shared with trusted individuals in
order to develop a fix, such information will not be published alongside
the fix or on any other disclosure channel without the permission of the
reporter. This includes but is not limited to the original bug report
and followup discussions (if any), exploits, CVE information or the
identity of the reporter.
In other words our only interest is in getting bugs fixed. All other
information submitted to the security list and any followup discussions
of the report are treated confidentially even after the embargo has been
lifted, in perpetuity.
Coordination
------------
Fixes for sensitive bugs, such as those that might lead to privilege
escalations, may need to be coordinated with the private
<linux-distros@vs.openwall.org> mailing list so that distribution vendors
are well prepared to issue a fixed kernel upon public disclosure of the
upstream fix. Distros will need some time to test the proposed patch and
will generally request at least a few days of embargo, and vendor update
publication prefers to happen Tuesday through Thursday. When appropriate,
the security team can assist with this coordination, or the reporter can
include linux-distros from the start. In this case, remember to prefix
the email Subject line with "[vs]" as described in the linux-distros wiki:
<http://oss-security.openwall.org/wiki/mailing-lists/distros#how-to-use-the-lists>
CVE assignment
--------------
The security team does not normally assign CVEs, nor do we require them
for reports or fixes, as this can needlessly complicate the process and
may delay the bug handling. If a reporter wishes to have a CVE identifier
assigned ahead of public disclosure, they will need to contact the private
linux-distros list, described above. When such a CVE identifier is known
before a patch is provided, it is desirable to mention it in the commit
message if the reporter agrees.
Non-disclosure agreements
-------------------------
The Linux kernel security team is not a formal body and therefore unable
to enter any non-disclosure agreements.