Re: [PATCH v11 03/12] landlock: Refactor landlock_find_rule/insert_rule

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On 15/05/2023 18:13, Konstantin Meskhidze wrote:
Add a new landlock_key union and landlock_id structure to support
a socket port rule type. A struct landlock_id identifies a unique entry
in a ruleset: either a kernel object (e.g inode) or typed data (e.g TCP
port). There is one red-black tree per key type.

This patch also adds is_object_pointer() and get_root() helpers.
is_object_pointer() returns true if key type is LANDLOCK_KEY_INODE.
get_root() helper returns a red_black tree root pointer according to
a key type.

Refactor landlock_insert_rule() and landlock_find_rule() to support coming
network modifications. Adding or searching a rule in ruleset can now be
done thanks to a Landlock ID argument passed to these helpers.

Co-developed-by: Mickaël Salaün <mic@xxxxxxxxxxx>
Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---

[...]

diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index 1f3188b4e313..deab37838f5b 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -35,7 +35,7 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers)
  		return ERR_PTR(-ENOMEM);
  	refcount_set(&new_ruleset->usage, 1);
  	mutex_init(&new_ruleset->lock);
-	new_ruleset->root = RB_ROOT;
+	new_ruleset->root_inode = RB_ROOT;
  	new_ruleset->num_layers = num_layers;
  	/*
  	 * hierarchy = NULL
@@ -68,8 +68,18 @@ static void build_check_rule(void)
  	BUILD_BUG_ON(rule.num_layers < LANDLOCK_MAX_NUM_LAYERS);
  }

+static bool is_object_pointer(const enum landlock_key_type key_type)
+{
+	switch (key_type) {
+	case LANDLOCK_KEY_INODE:
+		return true;

+	}


Because of enum change [1], could you please put the following block inside this commit's switch with a new "default:" case, and add a line break after the previous return like this:

\n
default:
+	WARN_ON_ONCE(1);
+	return false;

break;
}

+}
+
  static struct landlock_rule *
-create_rule(struct landlock_object *const object,
+create_rule(const struct landlock_id id,
  	    const struct landlock_layer (*const layers)[], const u32 num_layers,
  	    const struct landlock_layer *const new_layer)
  {
@@ -90,8 +100,13 @@ create_rule(struct landlock_object *const object,
  	if (!new_rule)
  		return ERR_PTR(-ENOMEM);
  	RB_CLEAR_NODE(&new_rule->node);
-	landlock_get_object(object);
-	new_rule->object = object;
+	if (is_object_pointer(id.type)) {
+		/* This should be catched by insert_rule(). */
+		WARN_ON_ONCE(!id.key.object);
+		landlock_get_object(id.key.object);
+	}
+
+	new_rule->key = id.key;
  	new_rule->num_layers = new_num_layers;
  	/* Copies the original layer stack. */
  	memcpy(new_rule->layers, layers,
@@ -102,12 +117,29 @@ create_rule(struct landlock_object *const object,
  	return new_rule;
  }

-static void free_rule(struct landlock_rule *const rule)
+static struct rb_root *get_root(struct landlock_ruleset *const ruleset,
+				const enum landlock_key_type key_type)
+{

Same here, you can remove the "root" variable:

+	struct rb_root *root = NULL;
+
+	switch (key_type) {
+	case LANDLOCK_KEY_INODE:
+		root = &ruleset->root_inode;
+		break;

return &ruleset->root_inode;
\n
default:
+	if (WARN_ON_ONCE(!root))
+		return ERR_PTR(-EINVAL);
break;
}

+}

Actually, I've pushed this change here: https://git.kernel.org/mic/c/8c96c7eee3ff (landlock-net-v11 branch)



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