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authorMickaël Salaün <mic@digikod.net>2022-05-06 19:10:52 +0300
committerMickaël Salaün <mic@digikod.net>2022-05-23 14:27:56 +0300
commit75c542d6c6cc48720376862d5496d51509160dfd (patch)
treef7411e602afa044becdad12369614e004c439fd1 /Documentation
parent5f2ff33e10843ef51275c8611bdb7b49537aba5d (diff)
downloadlinux-75c542d6c6cc48720376862d5496d51509160dfd.tar.xz
landlock: Reduce the maximum number of layers to 16
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/userspace-api/landlock.rst4
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
index f35552ff19ba..b68e7a51009f 100644
--- a/Documentation/userspace-api/landlock.rst
+++ b/Documentation/userspace-api/landlock.rst
@@ -267,8 +267,8 @@ restrict such paths with dedicated ruleset flags.
Ruleset layers
--------------
-There is a limit of 64 layers of stacked rulesets. This can be an issue for a
-task willing to enforce a new ruleset in complement to its 64 inherited
+There is a limit of 16 layers of stacked rulesets. This can be an issue for a
+task willing to enforce a new ruleset in complement to its 16 inherited
rulesets. Once this limit is reached, sys_landlock_restrict_self() returns
E2BIG. It is then strongly suggested to carefully build rulesets once in the
life of a thread, especially for applications able to launch other applications