driver core: check start node in klist_iter_init_node

klist_iter_init_node() takes a node as a start argument.
However, this node might not be valid anymore.
This patch updates the klist_iter_init_node() and
dependent functions to return an error if so.
All calling functions have been audited to check
for a return code here.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Greg Kroah-Hartmann <gregkh@linuxfoundation.org>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Stable Kernel <stable@kernel.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 60 insertions, 36 deletions

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 2bcef657a60c..76aed01a8b2c 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -296,11 +296,13 @@ int bus_for_each_dev(struct bus_type *bus, struct device *start,
 	if (!bus)
 		return -EINVAL;
 
-	klist_iter_init_node(&bus->p->klist_devices, &i,
-			     (start ? &start->p->knode_bus : NULL));
-	while ((dev = next_device(&i)) && !error)
-		error = fn(dev, data);
-	klist_iter_exit(&i);
+	error = klist_iter_init_node(&bus->p->klist_devices, &i,
+				     (start ? &start->p->knode_bus : NULL));
+	if (!error) {
+		while ((dev = next_device(&i)) && !error)
+			error = fn(dev, data);
+		klist_iter_exit(&i);
+	}
 	return error;
 }
 EXPORT_SYMBOL_GPL(bus_for_each_dev);
@@ -330,8 +332,10 @@ struct device *bus_find_device(struct bus_type *bus,
 	if (!bus)
 		return NULL;
 
-	klist_iter_init_node(&bus->p->klist_devices, &i,
-			     (start ? &start->p->knode_bus : NULL));
+	if (klist_iter_init_node(&bus->p->klist_devices, &i,
+				 (start ? &start->p->knode_bus : NULL)) < 0)
+		return NULL;
+
 	while ((dev = next_device(&i)))
 		if (match(dev, data) && get_device(dev))
 			break;
@@ -384,7 +388,9 @@ struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id
 		return NULL;
 
 	if (hint) {
-		klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
+		if (klist_iter_init_node(&subsys->p->klist_devices, &i,
+					 &hint->p->knode_bus) < 0)
+			return NULL;
 		dev = next_device(&i);
 		if (dev && dev->id == id && get_device(dev)) {
 			klist_iter_exit(&i);
@@ -446,11 +452,13 @@ int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
 	if (!bus)
 		return -EINVAL;
 
-	klist_iter_init_node(&bus->p->klist_drivers, &i,
-			     start ? &start->p->knode_bus : NULL);
-	while ((drv = next_driver(&i)) && !error)
-		error = fn(drv, data);
-	klist_iter_exit(&i);
+	error = klist_iter_init_node(&bus->p->klist_drivers, &i,
+				     start ? &start->p->knode_bus : NULL);
+	if (!error) {
+		while ((drv = next_driver(&i)) && !error)
+			error = fn(drv, data);
+		klist_iter_exit(&i);
+	}
 	return error;
 }
 EXPORT_SYMBOL_GPL(bus_for_each_drv);
@@ -1111,15 +1119,19 @@ EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
  * otherwise if it is NULL, the iteration starts at the beginning of
  * the list.
  */
-void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
-			  struct device *start, const struct device_type *type)
+int subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
+			 struct device *start, const struct device_type *type)
 {
 	struct klist_node *start_knode = NULL;
+	int error;
 
 	if (start)
 		start_knode = &start->p->knode_bus;
-	klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
-	iter->type = type;
+	error = klist_iter_init_node(&subsys->p->klist_devices, &iter->ki,
+				     start_knode);
+	if (!error)
+		iter->type = type;
+	return error;
 }
 EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
 
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 03243d4002fd..23dbc661d4a0 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -301,15 +301,20 @@ void class_destroy(struct class *cls)
  * otherwise if it is NULL, the iteration starts at the beginning of
  * the list.
  */
-void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
-			 struct device *start, const struct device_type *type)
+int class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
+			struct device *start, const struct device_type *type)
 {
 	struct klist_node *start_knode = NULL;
+	int error;
 
 	if (start)
 		start_knode = &start->knode_class;
-	klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
-	iter->type = type;
+	error = klist_iter_init_node(&class->p->klist_devices, &iter->ki,
+				     start_knode);
+	if (!error)
+		iter->type = type;
+
+	return error;
 }
 EXPORT_SYMBOL_GPL(class_dev_iter_init);
 
@@ -387,14 +392,15 @@ int class_for_each_device(struct class *class, struct device *start,
 		return -EINVAL;
 	}
 
-	class_dev_iter_init(&iter, class, start, NULL);
-	while ((dev = class_dev_iter_next(&iter))) {
-		error = fn(dev, data);
-		if (error)
-			break;
+	error = class_dev_iter_init(&iter, class, start, NULL);
+	if (!error) {
+		while ((dev = class_dev_iter_next(&iter))) {
+			error = fn(dev, data);
+			if (error)
+				break;
+		}
+		class_dev_iter_exit(&iter);
 	}
-	class_dev_iter_exit(&iter);
-
 	return error;
 }
 EXPORT_SYMBOL_GPL(class_for_each_device);
@@ -434,7 +440,9 @@ struct device *class_find_device(struct class *class, struct device *start,
 		return NULL;
 	}
 
-	class_dev_iter_init(&iter, class, start, NULL);
+	if (class_dev_iter_init(&iter, class, start, NULL) < 0)
+		return NULL;
+
 	while ((dev = class_dev_iter_next(&iter))) {
 		if (match(dev, data)) {
 			get_device(dev);
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 3ec3896c83a6..16f6dd2c4403 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -49,11 +49,13 @@ int driver_for_each_device(struct device_driver *drv, struct device *start,
 	if (!drv)
 		return -EINVAL;
 
-	klist_iter_init_node(&drv->p->klist_devices, &i,
-			     start ? &start->p->knode_driver : NULL);
-	while ((dev = next_device(&i)) && !error)
-		error = fn(dev, data);
-	klist_iter_exit(&i);
+	error = klist_iter_init_node(&drv->p->klist_devices, &i,
+				     start ? &start->p->knode_driver : NULL);
+	if (!error) {
+		while ((dev = next_device(&i)) && !error)
+			error = fn(dev, data);
+		klist_iter_exit(&i);
+	}
 	return error;
 }
 EXPORT_SYMBOL_GPL(driver_for_each_device);
@@ -83,8 +85,10 @@ struct device *driver_find_device(struct device_driver *drv,
 	if (!drv)
 		return NULL;
 
-	klist_iter_init_node(&drv->p->klist_devices, &i,
-			     (start ? &start->p->knode_driver : NULL));
+	if (klist_iter_init_node(&drv->p->klist_devices, &i,
+				 (start ? &start->p->knode_driver : NULL)) < 0)
+		return NULL;
+
 	while ((dev = next_device(&i)))
 		if (match(dev, data) && get_device(dev))
 			break;