@@ -23,6 +23,7 @@ struct user_namespace {
struct uid_gid_map projid_map;
struct kref kref;
struct user_namespace *parent;
+ int level;
kuid_t owner;
kgid_t group;
unsigned int proc_inum;
@@ -62,6 +62,9 @@ int create_user_ns(struct cred *new)
kgid_t group = new->egid;
int ret;
+ if (parent_ns->level > 32)
+ return -EUSERS;
+
/*
* Verify that we can not violate the policy of which files
* may be accessed that is specified by the root directory,
@@ -92,6 +95,7 @@ int create_user_ns(struct cred *new)
kref_init(&ns->kref);
/* Leave the new->user_ns reference with the new user namespace. */
ns->parent = parent_ns;
+ ns->level = parent_ns->level + 1;
ns->owner = owner;
ns->group = group;