Re: [PATCH] Documentation: Document the Linux Kernel CVE process

[Randy Dunlap]

On 2/13/24 10:48, Greg Kroah-Hartman wrote:
> The Linux kernel project now has the ability to assign CVEs to fixed
> issues, so document the process and how individual developers can get a
> CVE if one is not automatically assigned for their fixes.
> 
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
> ---
>  Documentation/process/cve.rst           | 116 ++++++++++++++++++++++++
>  Documentation/process/index.rst         |   1 +
>  Documentation/process/security-bugs.rst |   6 +-
>  3 files changed, 120 insertions(+), 3 deletions(-)
>  create mode 100644 Documentation/process/cve.rst
> 
> diff --git a/Documentation/process/cve.rst b/Documentation/process/cve.rst
> new file mode 100644
> index 000000000000..17df5d673102
> --- /dev/null
> +++ b/Documentation/process/cve.rst
> @@ -0,0 +1,116 @@
> +CVEs
> +====
> +
> +Common Vulnerabilities and Exposure (CVE®) numbers, were developed as an

                            no comma                 ^

> +unambiguous way to identify, define, and catalog publically disclosed

                                                    publicly

> +security vulnerabilities.  Over time, their usefulness has declined with
> +regards to the kernel project, and CVE numbers were very often assigned
> +in inappropriate ways and for inappropriate reasons.  Because of this,
> +the kernel development community has tended to avoid them.  However, the
> +combination of continuing pressure to assign CVEs and other forms of
> +security identifiers, and ongoing abuses by community members outside of
> +the kernel community has made it clear that the kernel community should
> +have control over those assignments.
> +
> +The Linux kernel developer team does have the ability to assign CVEs for
> +potential Linux kernel security issues.  This assignment is independent
> +of the :doc:`normal Linux kernel security bug reporting
> +process<../process/security_bugs>`.
> +
> +A list of all assigned CVEs for the Linux kernel can be found in the
> +archives of the linux-cve mailing list, as seen on
> +https://lore.kernel.org/linux-cve-announce/.  To get notice of the
> +assigned CVEs, please subscribe to that mailing list.
> +
> +Process
> +-------
> +
> +As part of the normal stable release process, kernel changes that are
> +potentially security issues are identified by the developers responsible
> +for CVE number assignments and have CVE numbers automatically assigned
> +to them.  These assignments are published on the linux-cve mailing list

                                                    linux-cve-announce mailing list

> +as announcements on a frequent basis.
> +
> +Note, due to the layer at which the Linux kernel is in a system, almost
> +any bug might be exploitable to compromise the security of the kernel,
> +but the possibility of exploitation is often not evident when the bug is
> +fixed.  Because of this, the CVE assignment team are overly cautious and

                                                    is
to be consistent.

> +assign CVE numbers to any bugfix that they identify.  This
> +explains the seemingly large number of CVEs that are issued by the Linux
> +kernel team.
> +
> +If the CVE assignment team misses a specific fix that any user feels
> +should have a CVE assigned to it, please email them at <cve@xxxxxxxxxx>
> +and the team there will work with you on it.  Note, that no potential

                             no comma                ^

> +security issues should be sent to this alias, it is ONLY for assignment
> +of CVEs for fixes that are already in released kernel trees.  If you
> +feel you have found an unfixed security issue, please follow the
> +:doc:`normal Linux kernel security bug reporting
> +process<../process/security_bugs>`.
> +
> +No CVEs will be assigned for unfixed security issues in the Linux
> +kernel, assignment will only happen after a fix is available as it can

   kernel;

> +be properly tracked that way by the git commit id of the original fix.
> +
> +No CVEs will be assigned for any issue found in a version of the kernel
> +that is not currently being actively supported by the Stable/LTS kernel
> +team.  A list of the currently supported kernel branches can be found at
> +https://kernel.org/category/releases.html
> +
> +Disputes of assigned CVEs
> +-------------------------
> +
> +The authority to dispute or modify an assigned CVE for a specific kernel
> +change lies solely with the maintainers of the relevant subsystem
> +affected.  This principle ensures a high degree of accuracy and
> +accountability in vulnerability reporting.  Only those individuals with
> +deep expertise and intimate knowledge of the subsystem can effectively
> +assess the validity and scope of a reported vulnerability and determine
> +its appropriate CVE designation.  Any attempt to modify or dispute a CVE
> +outside of this designated authority could lead to confusion, inaccurate
> +reporting, and ultimately, compromised systems.
> +
> +Invalid CVEs
> +------------
> +
> +If a security issue is found in a Linux kernel that is only supported by
> +a Linux distribution due to the changes that have been made by that
> +distribution, or due to the distribution supporting a kernel version
> +that is no longer one of the kernel.org supported releases, then a CVE
> +can not be assigned by the Linux kernel CVE team, and must be asked for
> +from that Linux distribution itself.
> +
> +Any CVE that is assigned against the Linux kernel for an actively
> +supported kernel version, by any group other than the kernel assignment
> +CVE team should not be treated as a valid CVE.  Please notify the
> +kernel CVE assignment team at <cve@xxxxxxxxxx> so that they can work to
> +invalidate such entries through the CNA remediation process.
> +
> +Applicability of specific CVEs
> +------------------------------
> +
> +As the Linux kernel can be used in many different ways, with many
> +different ways of accessing it by external users, or no access at all,
> +the applicability of any specific CVE is up to the user of Linux to
> +determine, it is not up to the CVE assignment team.  Please do not
> +contact us to attempt to determine the applicability of any specific
> +CVE.
> +
> +Also, as the source tree is so large, and any one system only uses a
> +small subset of the source tree, any users of Linux should be aware that
> +large numbers of assigned CVEs are not relevant for their systems.
> +
> +In short, we do not know your use case, and we do not know what portions
> +of the kernel that you use, so there is no way for us to determine if a
> +specific CVE is relevant for your system.
> +
> +As always, it is best to take all released kernel changes, as they are
> +tested together in a unified whole by many community members, and not as
> +individual cherry-picked changes.  Also note that for many bugs, the
> +solution to the overall problem is not found in a single change, but by
> +the sum of many fixes on top of each other.  Ideally CVEs will be
> +assigned to all fixes for all issues, but sometimes we do not notice
> +fixes in released kernels, so do not assume that because a specific
> +change does not have a CVE assigned to it, that it is not relevant to
> +take.
> +


-- 
#Randy