docs: security: Confidential computing intro and threat model for x86 virtualization

Kernel developers working on confidential computing for virtualized
environments in x86 operate under a set of assumptions regarding the Linux
kernel threat model that differs from the traditional view. Historically,
the Linux threat model acknowledges attackers residing in userspace, as
well as a limited set of external attackers that are able to interact with
the kernel through networking or limited HW-specific exposed interfaces
(e.g. USB, thunderbolt). The goal of this document is to explain additional
attack vectors that arise in the virtualized confidential computing space.

Reviewed-by: Larry Dewey <larry.dewey@amd.com>
Reviewed-by: David Kaplan <david.kaplan@amd.com>
Co-developed-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>

Message-ID: <98804f27-c2e7-74d6-d671-1eda927e19fe@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: security: Add secrets/coco documentation

Add documentation for the efi_secret module which allows access
to Confidential Computing injected secrets.

Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://lore.kernel.org/r/20220412212127.154182-5-dovmurik@linux.ibm.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

landlock: Add user and kernel documentation

Add a first document describing userspace API: how to define and enforce
a Landlock security policy. This is explained with a simple example.
The Landlock system calls are described with their expected behavior and
current limitations.

Another document is dedicated to kernel developers, describing guiding
principles and some important kernel structures.

This documentation can be built with the Sphinx framework.

Cc: James Morris <jmorris@namei.org>
Cc: Jann Horn <jannh@google.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: Vincent Dagonneau <vincent.dagonneau@ssi.gouv.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210422154123.13086-13-mic@digikod.net
Signed-off-by: James Morris <jamorris@linux.microsoft.com>

docs: move digsig docs to the security book

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6af5365404c7bd9d008e7e3a77ba83587fd33012.1588345503.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: security: move some books to it and update

The following files belong to security:

Documentation/security/LSM.rst -> Documentation/security/lsm-development.rst
Documentation/lsm.txt -> Documentation/security/lsm.rst
Documentation/SAK.txt -> Documentation/security/sak.rst
Documentation/siphash.txt -> Documentation/security/siphash.rst

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

doc: sctp: Merge and clean up rst files

The SCTP sections were ending up at the top-level table of contents
under the security section when they should have be sections with the
SCTP chapters. In addition to correcting the section and subsection
headings, this merges the SCTP documents into a single file to organize
the chapters more clearly, internally linkifies them, and adds the
missing SPDX header.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: */index.rst: Add newer documents to their respective index.rst

A number of new docs were added, but they're currently not on
the index.rst from the session they're supposed to be, causing
Sphinx warnings.

Add them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc: ReSTify keys.txt

This creates a new section in the security development index for kernel
keys, and adjusts for ReST markup.

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc: ReSTify and split LSM.txt

The existing LSM.txt file covered both usage and development, so split
this into two files, one under admin-guide and one under kernel
development.

Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc: ReSTify self-protection.txt

This updates the credentials API documentation to ReST markup and moves
it under the security subsection of kernel API documentation.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc: ReSTify credentials.txt

This updates the credentials API documentation to ReST markup and moves
it under the security subsection of kernel API documentation.

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc: ReSTify IMA-templates.txt

Adjust IMA-templates.txt for ReST markup and add to the index for
security/, under the Kernel API Documentation.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

tpm: move documentation under Documentation/security

In order too make Documentation root directory cleaner move the tpm
directory under Documentation/security.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>