On 09/09/2022 16:53, Konstantin Meskhidze (A) wrote:

9/6/2022 11:07 AM, Mickaël Salaün пишет:

quoted

On 29/08/2022 19:03, Konstantin Meskhidze wrote:

quoted

Refactors merge_ruleset() and inherit_ruleset() functions to support
new rule types. This patch adds merge_tree() and inherit_tree()
helpers. Each has key_type argument to choose a particular rb_tree
structure in a ruleset.

Signed-off-by: Konstantin Meskhidze <redacted>
---

Changes since v6:
* Refactors merge_ruleset() and inherit_ruleset() functions to support
    new rule types.
* Renames tree_merge() to merge_tree() (and reorder arguments), and
    tree_copy() to inherit_tree().

Changes since v5:
* Refactors some logic errors.
* Formats code with clang-format-14.

Changes since v4:
* None

---
   security/landlock/ruleset.c | 108 +++++++++++++++++++++++-------------
   1 file changed, 69 insertions(+), 39 deletions(-)

diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index 41de17d1869e..3a5ef356aaa3 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c

@@ -302,36 +302,18 @@ static void put_hierarchy(struct landlock_hierarchy *hierarchy)
   	}
   }

-static int merge_ruleset(struct landlock_ruleset *const dst,
-			 struct landlock_ruleset *const src)
+static int merge_tree(struct landlock_ruleset *const dst,
+		      struct landlock_ruleset *const src,
+		      const enum landlock_key_type key_type)
   {
   	struct landlock_rule *walker_rule, *next_rule;
   	struct rb_root *src_root;
   	int err = 0;

-	might_sleep();
-	/* Should already be checked by landlock_merge_ruleset() */
-	if (WARN_ON_ONCE(!src))
-		return 0;
-	/* Only merge into a domain. */
-	if (WARN_ON_ONCE(!dst || !dst->hierarchy))
-		return -EINVAL;
-
-	src_root = get_root(src, LANDLOCK_KEY_INODE);

This hunk is a bit misleading, but please add a might_sleep() call here
because of the insert_rule() call, and some lock asserts:

might_sleep();
lockdep_assert_held(&dst->lock);
lockdep_assert_held(&src->lock);

    it was moved into merge_ruleset() function,
    please check below.

I know but you still need to add these asserts.

quoted

quoted

+	src_root = get_root(src, key_type);
   	if (IS_ERR(src_root))
   		return PTR_ERR(src_root);

-	/* Locks @dst first because we are its only owner. */
-	mutex_lock(&dst->lock);
-	mutex_lock_nested(&src->lock, SINGLE_DEPTH_NESTING);
-
-	/* Stacks the new layer. */
-	if (WARN_ON_ONCE(src->num_layers != 1 || dst->num_layers < 1)) {
-		err = -EINVAL;
-		goto out_unlock;
-	}
-	dst->access_masks[dst->num_layers - 1] = src->access_masks[0];
-
   	/* Merges the @src tree. */
   	rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, src_root,
   					     node) {

@@ -340,7 +322,7 @@ static int merge_ruleset(struct landlock_ruleset *const dst,
   		} };
   		const struct landlock_id id = {
   			.key = walker_rule->key,
-			.type = LANDLOCK_KEY_INODE,
+			.type = key_type,
   		};

   		if (WARN_ON_ONCE(walker_rule->num_layers != 1))

@@ -351,8 +333,39 @@ static int merge_ruleset(struct landlock_ruleset *const dst,

   		err = insert_rule(dst, id, &layers, ARRAY_SIZE(layers));
   		if (err)
-			goto out_unlock;
+			return err;
+	}
+	return err;
+}
+
+static int merge_ruleset(struct landlock_ruleset *const dst,
+			 struct landlock_ruleset *const src)
+{
+	int err = 0;
+
+	might_sleep();
+	/* Should already be checked by landlock_merge_ruleset() */
+	if (WARN_ON_ONCE(!src))
+		return 0;
+	/* Only merge into a domain. */
+	if (WARN_ON_ONCE(!dst || !dst->hierarchy))
+		return -EINVAL;
+
+	/* Locks @dst first because we are its only owner. */
+	mutex_lock(&dst->lock);
+	mutex_lock_nested(&src->lock, SINGLE_DEPTH_NESTING);
+
+	/* Stacks the new layer. */
+	if (WARN_ON_ONCE(src->num_layers != 1 || dst->num_layers < 1)) {
+		err = -EINVAL;
+		goto out_unlock;
   	}
+	dst->access_masks[dst->num_layers - 1] = src->access_masks[0];
+
+	/* Merges the @src inode tree. */
+	err = merge_tree(dst, src, LANDLOCK_KEY_INODE);
+	if (err)
+		goto out_unlock;

   out_unlock:
   	mutex_unlock(&src->lock);

@@ -360,43 +373,60 @@ static int merge_ruleset(struct landlock_ruleset *const dst,
   	return err;
   }

-static int inherit_ruleset(struct landlock_ruleset *const parent,
-			   struct landlock_ruleset *const child)
+static int inherit_tree(struct landlock_ruleset *const parent,
+			struct landlock_ruleset *const child,
+			const enum landlock_key_type key_type)
   {
   	struct landlock_rule *walker_rule, *next_rule;
   	struct rb_root *parent_root;
   	int err = 0;

-	might_sleep();
-	if (!parent)
-		return 0;
-
-	parent_root = get_root(parent, LANDLOCK_KEY_INODE);

This hunk is a bit misleading, but please add a might_sleep() call here
because of the insert_rule() call, and some lock asserts:

might_sleep();
lockdep_assert_held(&parent->lock);
lockdep_assert_held(&child->lock);

    it was moved into inherit_ruleset() function,
    please check below.

same