Extend the kernel support section with one subsection for build time
configuration and another for boot time configuration.
Extend the boot time subsection with a concrete example.
Update the journalctl command to include the boot option.
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240227110550.3702236-1-mic@digikod.net
[mic: Improve wording as suggested by Günther]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Describe network access rules for TCP sockets. Add network access
example in the tutorial. Add kernel configuration support for network.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Link: https://lore.kernel.org/r/20231026014751.414649-13-konstantin.meskhidze@huawei.com
[mic: Update date, and do light cosmetic changes]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Allow mount point and root directory changes when there is no filesystem
rule tied to the current Landlock domain. This doesn't change anything
for now because a domain must have at least a (filesystem) rule, but
this will change when other rule types will come. For instance, a domain
only restricting the network should have no impact on filesystem
restrictions.
Add a new get_current_fs_domain() helper to quickly check filesystem
rule existence for all filesystem LSM hooks.
Remove unnecessary inlining.
Link: https://lore.kernel.org/r/20231026014751.414649-3-konstantin.meskhidze@huawei.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Use the LANDLOCK_ACCESS_FS_TRUNCATE flag in the tutorial.
Adapt the backwards compatibility example and discussion to remove the
truncation flag where needed.
Point out potential surprising behaviour related to truncate.
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20221018182216.301684-12-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
It seems that all code should use double backquotes, which is also used
to convert "%" defines. Let's use an homogeneous style and remove all
use of simple backquotes (which should only be used for emphasis).
Cc: Günther Noack <gnoack3000@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220923154207.3311629-4-mic@digikod.net
Now that we have more than one ABI version, make limitation explanation
more consistent by replacing "ABI 1" with "ABI < 2". This also
indicates which ABIs support such past limitation.
Improve documentation consistency by not using contractions.
Fix spelling in fs.c .
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20220923154207.3311629-3-mic@digikod.net
Let's help users by documenting how to enable and check for Landlock in
the kernel and the running system. The userspace-api section may not be
the best place for this but it still makes sense to put all the user
documentation at the same place.
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220513112743.156414-1-mic@digikod.net
Reviewed-by: Paul Moore <paul@paul-moore.com>
Explain how to set access rights per hierarchy in an efficient and safe
way, especially with the LANDLOCK_ACCESS_FS_REFER side effect (i.e.
partial ordering and constraints for access rights per hierarchy).
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-12-mic@digikod.net
Add LANDLOCK_ACCESS_FS_REFER in the example and properly check to only
use it if the current kernel support it thanks to the Landlock ABI
version.
Move the file renaming and linking limitation to a new "Previous
limitations" section.
Improve documentation about the backward and forward compatibility,
including the rational for ruleset's handled_access_fs.
Update the document date.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-11-mic@digikod.net
The maximum number of nested Landlock domains is currently 64. Because
of the following fix and to help reduce the stack size, let's reduce it
to 16. This seems large enough for a lot of use cases (e.g. sandboxed
init service, spawning a sandboxed SSH service, in nested sandboxed
containers). Reducing the number of nested domains may also help to
discover misuse of Landlock (e.g. creating a domain per rule).
Add and use a dedicated layer_mask_t typedef to fit with the number of
layers. This might be useful when changing it and to keep it consistent
with the maximum number of layers.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220506161102.525323-3-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
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>
