Commit 36f4c25c authored by Jakob Koschel's avatar Jakob Koschel Committed by Greg Kroah-Hartman
Browse files

usb: gadget: configfs: remove using list iterator after loop body as a ptr 

If the list does not contain the expected element, the value of
list_for_each_entry() iterator will not point to a valid structure.
To avoid type confusion in such case, the list iterator
scope will be limited to list_for_each_entry() loop.

In preparation to limiting scope of a list iterator to the list traversal
loop, use a dedicated pointer to point to the found element [1].
Determining if an element was found is then simply checking if
the pointer is != NULL instead of using the potentially bogus pointer.

Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/


Signed-off-by: default avatarJakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220308171818.384491-18-jakobkoschel@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6163d499

drivers/usb/gadget/configfs.c

+14 −10
Original line number Diff line number Diff line
@@ -418,7 +418,7 @@ static int config_usb_cfg_link( 


	struct usb_function_instance *fi =

			to_usb_function_instance(usb_func_ci);

	struct usb_function_instance *a_fi;

	struct usb_function_instance *a_fi = NULL, *iter;

	struct usb_function *f;

	int ret;
@@ -428,11 +428,13 @@ static int config_usb_cfg_link( 
	 * from another gadget or a random directory.

	 * Also a function instance can only be linked once.

	 */

	list_for_each_entry(a_fi, &gi->available_func, cfs_list) {

		if (a_fi == fi)

	list_for_each_entry(iter, &gi->available_func, cfs_list) {

		if (iter != fi)

			continue;

		a_fi = iter;

		break;

	}

	if (a_fi != fi) {

	if (!a_fi) {

		ret = -EINVAL;

		goto out;

	}
@@ -882,15 +884,17 @@ static int os_desc_link(struct config_item *os_desc_ci, 
	struct gadget_info *gi = os_desc_item_to_gadget_info(os_desc_ci);

	struct usb_composite_dev *cdev = &gi->cdev;

	struct config_usb_cfg *c_target = to_config_usb_cfg(usb_cfg_ci);

	struct usb_configuration *c;

	struct usb_configuration *c = NULL, *iter;

	int ret;



	mutex_lock(&gi->lock);

	list_for_each_entry(c, &cdev->configs, list) {

		if (c == &c_target->c)

	list_for_each_entry(iter, &cdev->configs, list) {

		if (iter != &c_target->c)

			continue;

		c = iter;

		break;

	}

	if (c != &c_target->c) {

	if (!c) {

		ret = -EINVAL;

		goto out;

	}