X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fuser.c;h=46d0165ca70c6b10240256fb1ccc2b3420c6c91e;hb=c0b4abdd529d8256acc4cf0094db385877f34ae6;hp=6608a3d8ca616712726911da18d35f6347e5ba45;hpb=94d6a5f7341ebaff53d4e41cc81fab37f0d9fbed;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/user.c b/kernel/user.c
index 6608a3d..46d0165 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -20,7 +20,7 @@
 
 struct user_namespace init_user_ns = {
 	.kref = {
-		.refcount	= ATOMIC_INIT(1),
+		.refcount	= ATOMIC_INIT(2),
 	},
 	.creator = &root_user,
 };
@@ -72,21 +72,7 @@ static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
 static void uid_hash_remove(struct user_struct *up)
 {
 	hlist_del_init(&up->uidhash_node);
-}
-
-static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
-{
-	struct user_struct *user;
-	struct hlist_node *h;
-
-	hlist_for_each_entry(user, h, hashent, uidhash_node) {
-		if (user->uid == uid) {
-			atomic_inc(&user->__count);
-			return user;
-		}
-	}
-
-	return NULL;
+	put_user_ns(up->user_ns);
 }
 
 #ifdef CONFIG_USER_SCHED
@@ -104,6 +90,8 @@ static int sched_create_user(struct user_struct *up)
 	if (IS_ERR(up->tg))
 		rc = -ENOMEM;
 
+	set_tg_uid(up);
+
 	return rc;
 }
 
@@ -116,6 +104,23 @@ static int sched_create_user(struct user_struct *up) { return 0; }
 
 #if defined(CONFIG_USER_SCHED) && defined(CONFIG_SYSFS)
 
+static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
+{
+	struct user_struct *user;
+	struct hlist_node *h;
+
+	hlist_for_each_entry(user, h, hashent, uidhash_node) {
+		if (user->uid == uid) {
+			/* possibly resurrect an "almost deleted" object */
+			if (atomic_inc_return(&user->__count) == 1)
+				cancel_delayed_work(&user->work);
+			return user;
+		}
+	}
+
+	return NULL;
+}
+
 static struct kset *uids_kset; /* represents the /sys/kernel/uids/ directory */
 static DEFINE_MUTEX(uids_mutex);
 
@@ -280,38 +285,35 @@ int __init uids_sysfs_init(void)
 	return uids_user_create(&root_user);
 }
 
-/* work function to remove sysfs directory for a user and free up
+/* delayed work function to remove sysfs directory for a user and free up
  * corresponding structures.
  */
-static void remove_user_sysfs_dir(struct work_struct *w)
+static void cleanup_user_struct(struct work_struct *w)
 {
-	struct user_struct *up = container_of(w, struct user_struct, work);
+	struct user_struct *up = container_of(w, struct user_struct, work.work);
 	unsigned long flags;
 	int remove_user = 0;
 
-	if (up->user_ns != &init_user_ns)
-		return;
 	/* Make uid_hash_remove() + sysfs_remove_file() + kobject_del()
 	 * atomic.
 	 */
 	uids_mutex_lock();
 
-	local_irq_save(flags);
-
-	if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
+	spin_lock_irqsave(&uidhash_lock, flags);
+	if (atomic_read(&up->__count) == 0) {
 		uid_hash_remove(up);
 		remove_user = 1;
-		spin_unlock_irqrestore(&uidhash_lock, flags);
-	} else {
-		local_irq_restore(flags);
 	}
+	spin_unlock_irqrestore(&uidhash_lock, flags);
 
 	if (!remove_user)
 		goto done;
 
-	kobject_uevent(&up->kobj, KOBJ_REMOVE);
-	kobject_del(&up->kobj);
-	kobject_put(&up->kobj);
+	if (up->user_ns == &init_user_ns) {
+		kobject_uevent(&up->kobj, KOBJ_REMOVE);
+		kobject_del(&up->kobj);
+		kobject_put(&up->kobj);
+	}
 
 	sched_destroy_user(up);
 	key_put(up->uid_keyring);
@@ -328,17 +330,28 @@ done:
  */
 static void free_user(struct user_struct *up, unsigned long flags)
 {
-	/* restore back the count */
-	atomic_inc(&up->__count);
+	INIT_DELAYED_WORK(&up->work, cleanup_user_struct);
+	schedule_delayed_work(&up->work, msecs_to_jiffies(1000));
 	spin_unlock_irqrestore(&uidhash_lock, flags);
-
-	put_user_ns(up->user_ns);
-	INIT_WORK(&up->work, remove_user_sysfs_dir);
-	schedule_work(&up->work);
 }
 
 #else	/* CONFIG_USER_SCHED && CONFIG_SYSFS */
 
+static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
+{
+	struct user_struct *user;
+	struct hlist_node *h;
+
+	hlist_for_each_entry(user, h, hashent, uidhash_node) {
+		if (user->uid == uid) {
+			atomic_inc(&user->__count);
+			return user;
+		}
+	}
+
+	return NULL;
+}
+
 int uids_sysfs_init(void) { return 0; }
 static inline int uids_user_create(struct user_struct *up) { return 0; }
 static inline void uids_mutex_lock(void) { }
@@ -355,12 +368,29 @@ static void free_user(struct user_struct *up, unsigned long flags)
 	sched_destroy_user(up);
 	key_put(up->uid_keyring);
 	key_put(up->session_keyring);
-	put_user_ns(up->user_ns);
 	kmem_cache_free(uid_cachep, up);
 }
 
 #endif
 
+#if defined(CONFIG_RT_GROUP_SCHED) && defined(CONFIG_USER_SCHED)
+/*
+ * We need to check if a setuid can take place. This function should be called
+ * before successfully completing the setuid.
+ */
+int task_can_switch_user(struct user_struct *up, struct task_struct *tsk)
+{
+
+	return sched_rt_can_attach(up->tg, tsk);
+
+}
+#else
+int task_can_switch_user(struct user_struct *up, struct task_struct *tsk)
+{
+	return 1;
+}
+#endif
+
 /*
  * Locate the user_struct for the passed UID.  If found, take a ref on it.  The
  * caller must undo that ref with free_uid().