Refactors merge_ruleset() and inherit_ruleset()
functions to support new rule types. This patch adds
tree_merge() and tree_copy() helpers. Each has
rule_type argument to choose a particular rb_tree
structure in a ruleset.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---
Changes since v5:
* Refactors some logic errors.
* Formats code with clang-format-14.
Changes since v4:
* None
---
security/landlock/ruleset.c | 153 +++++++++++++++++++++++++-----------
1 file changed, 105 insertions(+), 48 deletions(-)
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index 5f13f8a12aee..820b6e6a4496 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -110,12 +110,16 @@ create_rule(struct landlock_object *const object_ptr,
return new_rule;
}
-static void free_rule(struct landlock_rule *const rule)
+static void free_rule(struct landlock_rule *const rule, const u16 rule_type)
{
might_sleep();
if (!rule)
return;
- landlock_put_object(rule->object.ptr);
+ switch (rule_type) {
+ case LANDLOCK_RULE_PATH_BENEATH:
+ landlock_put_object(rule->object.ptr);
+ break;
+ }
kfree(rule);
}
@@ -222,13 +226,13 @@ static int insert_rule(struct landlock_ruleset *const ruleset,
case LANDLOCK_RULE_PATH_BENEATH:
new_rule = create_rule(object_ptr, 0, &this->layers,
this->num_layers, &(*layers)[0]);
+ if (IS_ERR(new_rule))
+ return PTR_ERR(new_rule);
+ rb_replace_node(&this->node, &new_rule->node,
+ &ruleset->root_inode);
+ free_rule(this, rule_type);
break;
}
- if (IS_ERR(new_rule))
- return PTR_ERR(new_rule);
- rb_replace_node(&this->node, &new_rule->node,
- &ruleset->root_inode);
- free_rule(this);
return 0;
}
@@ -239,13 +243,13 @@ static int insert_rule(struct landlock_ruleset *const ruleset,
switch (rule_type) {
case LANDLOCK_RULE_PATH_BENEATH:
new_rule = create_rule(object_ptr, 0, layers, num_layers, NULL);
+ if (IS_ERR(new_rule))
+ return PTR_ERR(new_rule);
+ rb_link_node(&new_rule->node, parent_node, walker_node);
+ rb_insert_color(&new_rule->node, &ruleset->root_inode);
+ ruleset->num_rules++;
break;
}
- if (IS_ERR(new_rule))
- return PTR_ERR(new_rule);
- rb_link_node(&new_rule->node, parent_node, walker_node);
- rb_insert_color(&new_rule->node, &ruleset->root_inode);
- ruleset->num_rules++;
return 0;
}
@@ -293,10 +297,54 @@ static void put_hierarchy(struct landlock_hierarchy *hierarchy)
}
}
+static int tree_merge(struct landlock_ruleset *const src,
+ struct landlock_ruleset *const dst, u16 rule_type)
+{
+ struct landlock_rule *walker_rule, *next_rule;
+ struct rb_root *src_root;
+ int err = 0;
+
+ /* Chooses rb_tree structure depending on a rule type. */
+ switch (rule_type) {
+ case LANDLOCK_RULE_PATH_BENEATH:
+ src_root = &src->root_inode;
+ break;
+ default:
+ return -EINVAL;
+ }
+ /* Merges the @src tree. */
+ rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, src_root,
+ node) {
+ struct landlock_layer layers[] = { {
+ .level = dst->num_layers,
+ } };
+
+ if (WARN_ON_ONCE(walker_rule->num_layers != 1)) {
+ err = -EINVAL;
+ return err;
+ }
+ if (WARN_ON_ONCE(walker_rule->layers[0].level != 0)) {
+ err = -EINVAL;
+ return err;
+ }
+ layers[0].access = walker_rule->layers[0].access;
+
+ switch (rule_type) {
+ case LANDLOCK_RULE_PATH_BENEATH:
+ err = insert_rule(dst, walker_rule->object.ptr, 0,
+ rule_type, &layers,
+ ARRAY_SIZE(layers));
+ break;
+ }
+ if (err)
+ return err;
+ }
+ return err;
+}
+
static int merge_ruleset(struct landlock_ruleset *const dst,
struct landlock_ruleset *const src)
{
- struct landlock_rule *walker_rule, *next_rule;
int err = 0;
might_sleep();
@@ -318,28 +366,10 @@ static int merge_ruleset(struct landlock_ruleset *const dst,
}
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_inode, node) {
- struct landlock_layer layers[] = { {
- .level = dst->num_layers,
- } };
-
- if (WARN_ON_ONCE(walker_rule->num_layers != 1)) {
- err = -EINVAL;
- goto out_unlock;
- }
- if (WARN_ON_ONCE(walker_rule->layers[0].level != 0)) {
- err = -EINVAL;
- goto out_unlock;
- }
- layers[0].access = walker_rule->layers[0].access;
- err = insert_rule(dst, walker_rule->object.ptr, 0,
- LANDLOCK_RULE_PATH_BENEATH, &layers,
- ARRAY_SIZE(layers));
- if (err)
- goto out_unlock;
- }
+ /* Merges the @src inode tree. */
+ err = tree_merge(src, dst, LANDLOCK_RULE_PATH_BENEATH);
+ if (err)
+ goto out_unlock;
out_unlock:
mutex_unlock(&src->lock);
@@ -347,10 +377,40 @@ static int merge_ruleset(struct landlock_ruleset *const dst,
return err;
}
+static int tree_copy(struct landlock_ruleset *const parent,
+ struct landlock_ruleset *const child, u16 rule_type)
+{
+ struct landlock_rule *walker_rule, *next_rule;
+ struct rb_root *parent_root;
+ int err = 0;
+
+ /* Chooses rb_tree structure depending on a rule type. */
+ switch (rule_type) {
+ case LANDLOCK_RULE_PATH_BENEATH:
+ parent_root = &parent->root_inode;
+ break;
+ default:
+ return -EINVAL;
+ }
+ /* Copies the @parent inode tree. */
+ rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
+ parent_root, node) {
+ switch (rule_type) {
+ case LANDLOCK_RULE_PATH_BENEATH:
+ err = insert_rule(child, walker_rule->object.ptr, 0,
+ rule_type, &walker_rule->layers,
+ walker_rule->num_layers);
+ break;
+ }
+ if (err)
+ return err;
+ }
+ return err;
+}
+
static int inherit_ruleset(struct landlock_ruleset *const parent,
struct landlock_ruleset *const child)
{
- struct landlock_rule *walker_rule, *next_rule;
int err = 0;
might_sleep();
@@ -361,22 +421,19 @@ static int inherit_ruleset(struct landlock_ruleset *const parent,
mutex_lock(&child->lock);
mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING);
- /* Copies the @parent tree. */
- rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
- &parent->root_inode, node) {
- err = insert_rule(child, walker_rule->object.ptr, 0,
- LANDLOCK_RULE_PATH_BENEATH,
- &walker_rule->layers,
- walker_rule->num_layers);
- if (err)
- goto out_unlock;
- }
+ /* Copies the @parent inode tree. */
+ err = tree_copy(parent, child, LANDLOCK_RULE_PATH_BENEATH);
+ 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));
@@ -400,7 +457,7 @@ static void free_ruleset(struct landlock_ruleset *const ruleset)
might_sleep();
rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode,
node)
- free_rule(freeme);
+ free_rule(freeme, LANDLOCK_RULE_PATH_BENEATH);
put_hierarchy(ruleset->hierarchy);
kfree(ruleset);
}
--
2.25.1
