landlock: Move domain hierarchy management

Create a new domain.h file containing the struct landlock_hierarchy
definition and helpers.  This type will grow with audit support.  This
also prepares for a new domain type.

Cc: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20250320190717.2287696-4-mic@digikod.net
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>

diff --git a/security/landlock/domain.h b/security/landlock/domain.h
new file mode 100644 (file)
index 0000000..d22712e
--- /dev/null
+++ b/security/landlock/domain.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock - Domain management
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_DOMAIN_H
+#define _SECURITY_LANDLOCK_DOMAIN_H
+
+#include <linux/mm.h>
+#include <linux/refcount.h>
+
+/**
+ * struct landlock_hierarchy - Node in a domain hierarchy
+ */
+struct landlock_hierarchy {
+       /**
+        * @parent: Pointer to the parent node, or NULL if it is a root
+        * Landlock domain.
+        */
+       struct landlock_hierarchy *parent;
+       /**
+        * @usage: Number of potential children domains plus their parent
+        * domain.
+        */
+       refcount_t usage;
+};
+
+static inline void
+landlock_get_hierarchy(struct landlock_hierarchy *const hierarchy)
+{
+       if (hierarchy)
+               refcount_inc(&hierarchy->usage);
+}
+
+static inline void landlock_put_hierarchy(struct landlock_hierarchy *hierarchy)
+{
+       while (hierarchy && refcount_dec_and_test(&hierarchy->usage)) {
+               const struct landlock_hierarchy *const freeme = hierarchy;
+
+               hierarchy = hierarchy->parent;
+               kfree(freeme);
+       }
+}
+
+#endif /* _SECURITY_LANDLOCK_DOMAIN_H */

diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index bff4e40a3093c8ad9750373d3e2b52e8213430b3..adb7f87828df57d89fb7b4857bc31b81c79dd7ee 100644 (file)
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -23,6 +23,7 @@
 #include <linux/workqueue.h>
 
 #include "access.h"
+#include "domain.h"
 #include "limits.h"
 #include "object.h"
 #include "ruleset.h"
@@ -307,22 +308,6 @@ int landlock_insert_rule(struct landlock_ruleset *const ruleset,
        return insert_rule(ruleset, id, &layers, ARRAY_SIZE(layers));
 }
 
-static void get_hierarchy(struct landlock_hierarchy *const hierarchy)
-{
-       if (hierarchy)
-               refcount_inc(&hierarchy->usage);
-}
-
-static void put_hierarchy(struct landlock_hierarchy *hierarchy)
-{
-       while (hierarchy && refcount_dec_and_test(&hierarchy->usage)) {
-               const struct landlock_hierarchy *const freeme = hierarchy;
-
-               hierarchy = hierarchy->parent;
-               kfree(freeme);
-       }
-}
-
 static int merge_tree(struct landlock_ruleset *const dst,
                      struct landlock_ruleset *const src,
                      const enum landlock_key_type key_type)
@@ -477,7 +462,7 @@ static int inherit_ruleset(struct landlock_ruleset *const parent,
                err = -EINVAL;
                goto out_unlock;
        }
-       get_hierarchy(parent->hierarchy);
+       landlock_get_hierarchy(parent->hierarchy);
        child->hierarchy->parent = parent->hierarchy;
 
 out_unlock:
@@ -501,7 +486,7 @@ static void free_ruleset(struct landlock_ruleset *const ruleset)
                free_rule(freeme, LANDLOCK_KEY_NET_PORT);
 #endif /* IS_ENABLED(CONFIG_INET) */
 
-       put_hierarchy(ruleset->hierarchy);
+       landlock_put_hierarchy(ruleset->hierarchy);
        kfree(ruleset);
 }
 

diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index 52f4f0af6ab07595199b577318f5160f3acf9590..bbb5996545d27fe0747b956dd39c470446699640 100644 (file)
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -17,6 +17,7 @@
 #include <linux/workqueue.h>
 
 #include "access.h"
+#include "domain.h"
 #include "limits.h"
 #include "object.h"
 
@@ -108,22 +109,6 @@ struct landlock_rule {
        struct landlock_layer layers[] __counted_by(num_layers);
 };
 
-/**
- * struct landlock_hierarchy - Node in a ruleset hierarchy
- */
-struct landlock_hierarchy {
-       /**
-        * @parent: Pointer to the parent node, or NULL if it is a root
-        * Landlock domain.
-        */
-       struct landlock_hierarchy *parent;
-       /**
-        * @usage: Number of potential children domains plus their parent
-        * domain.
-        */
-       refcount_t usage;
-};
-
 /**
  * struct landlock_ruleset - Landlock ruleset
  *

diff --git a/security/landlock/task.c b/security/landlock/task.c
index 4578ce6e319d830d184961ddcd87c1c118ce7f4c..e04646d80e781598c395f5325cc395c2966b8746 100644 (file)
--- a/security/landlock/task.c
+++ b/security/landlock/task.c
@@ -19,6 +19,7 @@
 
 #include "common.h"
 #include "cred.h"
+#include "domain.h"
 #include "fs.h"
 #include "ruleset.h"
 #include "setup.h"