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-rw-r--r--kernel/user_namespace.c74
1 files changed, 60 insertions, 14 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a58a219b99c6..86b7854fec8e 100644
--- 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)
{