Refactor merge_ruleset() and inherit_ruleset() functions to support
new rule types. This patch adds merge_tree() and inherit_tree()
helpers. They use a specific ruleset's red-black tree according to
a key type argument.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---
Changes since v8:
* Refactors commit message.
* Minor fixes.
Changes since v7:
* Adds missed lockdep_assert_held it inherit_tree() and merge_tree().
* Fixes comment.
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, 73 insertions(+), 35 deletions(-)
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index c5c88a100f74..3e1cffda128e 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -302,36 +302,22 @@ 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;
+ lockdep_assert_held(&dst->lock);
+ lockdep_assert_held(&src->lock);
- src_root = get_root(src, LANDLOCK_KEY_INODE);
+ 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 +326,7 @@ 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 +337,39 @@ 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 +377,64 @@ 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;
+ lockdep_assert_held(&parent->lock);
+ lockdep_assert_held(&child->lock);
- parent_root = get_root(parent, LANDLOCK_KEY_INODE);
+ parent_root = get_root(parent, key_type);
if (IS_ERR(parent_root))
return PTR_ERR(parent_root);
- /* Locks @child first because we are its only owner. */
- mutex_lock(&child->lock);
- mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING);
-
- /* Copies the @parent tree. */
+ /* Copies the @parent inode or network tree. */
rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
parent_root, node) {
const struct landlock_id id = {
.key = walker_rule->key,
- .type = LANDLOCK_KEY_INODE,
+ .type = key_type,
};
+
err = insert_rule(child, id, &walker_rule->layers,
walker_rule->num_layers);
if (err)
- goto out_unlock;
+ return err;
}
+ return err;
+}
+
+static int inherit_ruleset(struct landlock_ruleset *const parent,
+ struct landlock_ruleset *const child)
+{
+ int err = 0;
+
+ might_sleep();
+ if (!parent)
+ return 0;
+
+ /* Locks @child first because we are its only owner. */
+ mutex_lock(&child->lock);
+ mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING);
+
+ /* Copies the @parent inode tree. */
+ err = inherit_tree(parent, child, LANDLOCK_KEY_INODE);
+ if (err)
+ goto out_unlock;
if (WARN_ON_ONCE(child->num_layers <= parent->num_layers)) {
err = -EINVAL;
goto out_unlock;
}
- /* Copies the parent layer stack and leaves a space for the new layer. */
+ /*
+ * Copies the parent layer stack and leaves a space
+ * for the new layer.
+ */
memcpy(child->access_masks, parent->access_masks,
flex_array_size(parent, access_masks, parent->num_layers));
--
2.25.1
