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-rw-r--r--kernel/user_namespace.c75
1 files changed, 30 insertions, 45 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 0d9c51d6733..79084311ee5 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -9,70 +9,55 @@
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/user_namespace.h>
+#include <linux/cred.h>
/*
- * Clone a new ns copying an original user ns, setting refcount to 1
- * @old_ns: namespace to clone
- * Return NULL on error (failure to kmalloc), new ns otherwise
+ * Create a new user namespace, deriving the creator from the user in the
+ * passed credentials, and replacing that user with the new root user for the
+ * new namespace.
+ *
+ * This is called by copy_creds(), which will finish setting the target task's
+ * credentials.
*/
-static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
+int create_user_ns(struct cred *new)
{
struct user_namespace *ns;
- struct user_struct *new_user;
- struct cred *new;
+ struct user_struct *root_user;
int n;
ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
if (!ns)
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
kref_init(&ns->kref);
for (n = 0; n < UIDHASH_SZ; ++n)
INIT_HLIST_HEAD(ns->uidhash_table + n);
- /* Insert new root user. */
- ns->root_user = alloc_uid(ns, 0);
- if (!ns->root_user) {
+ /* Alloc new root user. */
+ root_user = alloc_uid(ns, 0);
+ if (!root_user) {
kfree(ns);
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
}
- /* Reset current->user with a new one */
- new_user = alloc_uid(ns, current_uid());
- if (!new_user) {
- free_uid(ns->root_user);
- kfree(ns);
- return ERR_PTR(-ENOMEM);
- }
-
- /* Install the new user */
- new = prepare_creds();
- if (!new) {
- free_uid(new_user);
- free_uid(ns->root_user);
- kfree(ns);
- }
- free_uid(new->user);
- new->user = new_user;
- commit_creds(new);
- return ns;
-}
-
-struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
-{
- struct user_namespace *new_ns;
-
- BUG_ON(!old_ns);
- get_user_ns(old_ns);
-
- if (!(flags & CLONE_NEWUSER))
- return old_ns;
+ /* set the new root user in the credentials under preparation */
+ ns->creator = new->user;
+ new->user = root_user;
+ new->uid = new->euid = new->suid = new->fsuid = 0;
+ new->gid = new->egid = new->sgid = new->fsgid = 0;
+ put_group_info(new->group_info);
+ new->group_info = get_group_info(&init_groups);
+#ifdef CONFIG_KEYS
+ key_put(new->request_key_auth);
+ new->request_key_auth = NULL;
+#endif
+ /* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
- new_ns = clone_user_ns(old_ns);
+ /* alloc_uid() incremented the userns refcount. Just set it to 1 */
+ kref_set(&ns->kref, 1);
- put_user_ns(old_ns);
- return new_ns;
+ return 0;
}
void free_user_ns(struct kref *kref)
@@ -80,7 +65,7 @@ void free_user_ns(struct kref *kref)
struct user_namespace *ns;
ns = container_of(kref, struct user_namespace, kref);
- release_uids(ns);
+ free_uid(ns->creator);
kfree(ns);
}
EXPORT_SYMBOL(free_user_ns);