Merge branch 'nsfs-ioctls' into HEAD

[cascardo/linux.git] / kernel / user_namespace.c

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a58a219..86b7854 100644 (file)
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -29,6 +29,17 @@ static DEFINE_MUTEX(userns_state_mutex);
 static bool new_idmap_permitted(const struct file *file,
                                struct user_namespace *ns, int cap_setid,
                                struct uid_gid_map *map);
+static void free_user_ns(struct work_struct *work);
+
+static struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid)
+{
+       return inc_ucount(ns, uid, UCOUNT_USER_NAMESPACES);
+}
+
+static void dec_user_namespaces(struct ucounts *ucounts)
+{
+       return dec_ucount(ucounts, UCOUNT_USER_NAMESPACES);
+}
 
 static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
 {
@@ -62,10 +73,16 @@ int create_user_ns(struct cred *new)
        struct user_namespace *ns, *parent_ns = new->user_ns;
        kuid_t owner = new->euid;
        kgid_t group = new->egid;
-       int ret;
+       struct ucounts *ucounts;
+       int ret, i;
 
+       ret = -ENOSPC;
        if (parent_ns->level > 32)
-               return -EUSERS;
+               goto fail;
+
+       ucounts = inc_user_namespaces(parent_ns, owner);
+       if (!ucounts)
+               goto fail;
 
        /*
         * Verify that we can not violate the policy of which files
@@ -73,26 +90,27 @@ int create_user_ns(struct cred *new)
         * by verifing that the root directory is at the root of the
         * mount namespace which allows all files to be accessed.
         */
+       ret = -EPERM;
        if (current_chrooted())
-               return -EPERM;
+               goto fail_dec;
 
        /* The creator needs a mapping in the parent user namespace
         * or else we won't be able to reasonably tell userspace who
         * created a user_namespace.
         */
+       ret = -EPERM;
        if (!kuid_has_mapping(parent_ns, owner) ||
            !kgid_has_mapping(parent_ns, group))
-               return -EPERM;
+               goto fail_dec;
 
+       ret = -ENOMEM;
        ns = kmem_cache_zalloc(user_ns_cachep, GFP_KERNEL);
        if (!ns)
-               return -ENOMEM;
+               goto fail_dec;
 
        ret = ns_alloc_inum(&ns->ns);
-       if (ret) {
-               kmem_cache_free(user_ns_cachep, ns);
-               return ret;
-       }
+       if (ret)
+               goto fail_free;
        ns->ns.ops = &userns_operations;
 
        atomic_set(&ns->count, 1);
@@ -101,18 +119,37 @@ int create_user_ns(struct cred *new)
        ns->level = parent_ns->level + 1;
        ns->owner = owner;
        ns->group = group;
+       INIT_WORK(&ns->work, free_user_ns);
+       for (i = 0; i < UCOUNT_COUNTS; i++) {
+               ns->ucount_max[i] = INT_MAX;
+       }
+       ns->ucounts = ucounts;
 
        /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */
        mutex_lock(&userns_state_mutex);
        ns->flags = parent_ns->flags;
        mutex_unlock(&userns_state_mutex);
 
-       set_cred_user_ns(new, ns);
-
 #ifdef CONFIG_PERSISTENT_KEYRINGS
        init_rwsem(&ns->persistent_keyring_register_sem);
 #endif
+       ret = -ENOMEM;
+       if (!setup_userns_sysctls(ns))
+               goto fail_keyring;
+
+       set_cred_user_ns(new, ns);
        return 0;
+fail_keyring:
+#ifdef CONFIG_PERSISTENT_KEYRINGS
+       key_put(ns->persistent_keyring_register);
+#endif
+       ns_free_inum(&ns->ns);
+fail_free:
+       kmem_cache_free(user_ns_cachep, ns);
+fail_dec:
+       dec_user_namespaces(ucounts);
+fail:
+       return ret;
 }
 
 int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
@@ -135,21 +172,30 @@ int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
        return err;
 }
 
-void free_user_ns(struct user_namespace *ns)
+static void free_user_ns(struct work_struct *work)
 {
-       struct user_namespace *parent;
+       struct user_namespace *parent, *ns =
+               container_of(work, struct user_namespace, work);
 
        do {
+               struct ucounts *ucounts = ns->ucounts;
                parent = ns->parent;
+               retire_userns_sysctls(ns);
 #ifdef CONFIG_PERSISTENT_KEYRINGS
                key_put(ns->persistent_keyring_register);
 #endif
                ns_free_inum(&ns->ns);
                kmem_cache_free(user_ns_cachep, ns);
+               dec_user_namespaces(ucounts);
                ns = parent;
        } while (atomic_dec_and_test(&parent->count));
 }
-EXPORT_SYMBOL(free_user_ns);
+
+void __put_user_ns(struct user_namespace *ns)
+{
+       schedule_work(&ns->work);
+}
+EXPORT_SYMBOL(__put_user_ns);
 
 static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count)
 {