[RFC][PATCH 1/2] add user namespace [try #2]

[clg at fr.ibm.com (Cedric Le Goater)]

Cedric Le Goater wrote:
> Dave Hansen wrote:
>> On Mon, 2006-08-28 at 16:56 +0200, Cedric Le Goater wrote:
>>> + * 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
>>> + */
>>> +static struct user_namespace *clone_user_ns(struct user_namespace
>>> *old_ns)
>>> +{
>>> +       struct user_namespace *ns;
>>> +
>>> +       ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
>>> +       if (ns) {
>>> +               int n;
>>> +               struct user_struct *new_user;
>>> +
>>> +               kref_init(&ns->kref);
>>> +
>>> +               for(n = 0; n < UIDHASH_SZ; ++n)
>>> +                       INIT_LIST_HEAD(ns->uidhash_table + n);
>>> +
>>> +               /* Insert new root user.  */
>>> +               ns->root_user = alloc_uid(ns, 0);
>>> +               if (!ns->root_user) {
>>> +                       kfree(ns);
>>> +                       return NULL;
>>> +               }
>>> +
>>> +               /* Reset current->user with a new one */
>>> +               new_user = alloc_uid(ns, current->uid);
>>> +               if (!new_user) {
>>> +                       kfree(ns);
>>> +                       return NULL;
>>> +               }
>> Does this leak the ns->root_user?
> 
> arg !
> 
> thanks,

Sorry, I forgot to include the fix.

C.

Signed-off-by: Cedric Le Goater <clg at fr.ibm.com>

---
 kernel/user.c |    1 +
 1 file changed, 1 insertion(+)

Index: 2.6.18-rc4-mm3/kernel/user.c
===================================================================
--- 2.6.18-rc4-mm3.orig/kernel/user.c
+++ 2.6.18-rc4-mm3/kernel/user.c
@@ -125,6 +125,7 @@ static struct user_namespace *clone_user
 		/* 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 NULL;
 		}