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authorMickaël Salaün <mic@digikod.net>2022-05-06 18:10:52 +0200
committerMickaël Salaün <mic@digikod.net>2022-05-23 13:27:56 +0200
commit75c542d6c6cc48720376862d5496d51509160dfd (patch)
treef7411e602afa044becdad12369614e004c439fd1 /security/landlock/ruleset.h
parentlandlock: Define access_mask_t to enforce a consistent access mask size (diff)
downloadlinux-75c542d6c6cc48720376862d5496d51509160dfd.tar.xz
linux-75c542d6c6cc48720376862d5496d51509160dfd.zip
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 'security/landlock/ruleset.h')
-rw-r--r--security/landlock/ruleset.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index 8d5717594931..521af2848951 100644
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -23,6 +23,10 @@ typedef u16 access_mask_t;
/* Makes sure all filesystem access rights can be stored. */
static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS);
+typedef u16 layer_mask_t;
+/* Makes sure all layers can be checked. */
+static_assert(BITS_PER_TYPE(layer_mask_t) >= LANDLOCK_MAX_NUM_LAYERS);
+
/**
* struct landlock_layer - Access rights for a given layer
*/