[PATCH] Resource leak in reparent_to_init

[PATCH] Resource leak in reparent_to_init

[Vladimir Kondratiev]

In reparent_to_init, it is clear bug that causes resource leak. It is 
pretty easy to test that this bug causes problems: if your module allows 
to create thread for non-root user (using daemonize() and 
reparent_to_init()), it will mis-count number of processes running for 
that user.
Patch follows.
P.S. I do not subscribed to the list, thus please in your reply CC me 
(vladimir.kondratiev@intel.com)

--- kernel/sched.c.orig    2003-08-17 20:12:14.000000000 +0300
+++ kernel/sched.c    2003-08-17 21:21:08.000000000 +0300
@@ -1274,8 +1274,16 @@
    this_task->cap_permitted = CAP_FULL_SET;
    this_task->keep_capabilities = 0;
    memcpy(this_task->rlim, init_task.rlim, sizeof(*(this_task->rlim)));
-    this_task->user = INIT_USER;
-
+    if (this_task->uid) { /* not root? switch user */
+        struct user_struct *old_user = this_task->user,
+            *new_user = INIT_USER;
+        this_task->uid = 0;
+        this_task->user = new_user;
+        atomic_inc(&new_user->__count);
+        atomic_inc(&new_user->processes);
+        atomic_dec(&old_user->processes);
+        free_uid(old_user);
+    }
    spin_unlock(&runqueue_lock);
    write_unlock_irq(&tasklist_lock);
}