@@ -102,6 +102,10 @@ int landlock_insert_rule(struct landlock_ruleset *const ruleset,
might_sleep();
lockdep_assert_held(&ruleset->lock);
+ if (WARN_ON_ONCE(!rule->object))
+ return -ENOENT;
+ if (!is_merge && WARN_ON_ONCE(ruleset->nb_layers != 0))
+ return -EINVAL;
walker_node = &(ruleset->root.rb_node);
while (*walker_node) {
struct landlock_rule *const this = rb_entry(*walker_node,
@@ -223,12 +227,7 @@ static struct landlock_ruleset *inherit_ruleset(
return new_ruleset;
mutex_lock(&new_ruleset->lock);
- mutex_lock_nested(&parent->lock, 1);
- new_ruleset->nb_layers = parent->nb_layers;
- new_ruleset->fs_access_mask = parent->fs_access_mask;
- WARN_ON_ONCE(!parent->hierarchy);
- get_hierarchy(parent->hierarchy);
- new_ruleset->hierarchy->parent = parent->hierarchy;
+ mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING);
/* Copies the @parent tree. */
rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
@@ -237,6 +236,12 @@ static struct landlock_ruleset *inherit_ruleset(
if (err)
goto out_unlock;
}
+ new_ruleset->nb_layers = parent->nb_layers;
+ new_ruleset->fs_access_mask = parent->fs_access_mask;
+ WARN_ON_ONCE(!parent->hierarchy);
+ get_hierarchy(parent->hierarchy);
+ new_ruleset->hierarchy->parent = parent->hierarchy;
+
mutex_unlock(&parent->lock);
mutex_unlock(&new_ruleset->lock);
return new_ruleset;
Make sure that there is always an (allocated) object in each used rules. This could have prevented the bug fixed with a previous commit. When the rules from a ruleset are merged in a domain with landlock_enforce_ruleset_current(2), these new rules should be assigned to the last layer. However, when a rule is just extending a ruleset with landlock_add_rule(2), the number of layers of this updated ruleset should always be 0. Checking such use of landlock_insert_rule() could enable to detect bugs in future developments. Replace the hardcoded 1 with SINGLE_DEPTH_NESTING. Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@digikod.net> --- security/landlock/ruleset.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)