Commit eb6db9cc authored by Jakob Koschel's avatar Jakob Koschel Committed by Greg Kroah-Hartman
Browse files

usb: gadget: legacy: 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/20220308171818.384491-19-jakobkoschel@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 36f4c25c

drivers/usb/gadget/legacy/hid.c

+12 −11
Original line number Original line Diff line number Diff line
@@ -134,7 +134,7 @@ static int hid_bind(struct usb_composite_dev *cdev) 
{

{

	struct usb_gadget *gadget = cdev->gadget;

	struct usb_gadget *gadget = cdev->gadget;

	struct list_head *tmp;

	struct list_head *tmp;

	struct hidg_func_node *n, *m;

	struct hidg_func_node *n = NULL, *m, *iter_n;

	struct f_hid_opts *hid_opts;

	struct f_hid_opts *hid_opts;

	int status, funcs = 0;

	int status, funcs = 0;
@@ -144,18 +144,19 @@ static int hid_bind(struct usb_composite_dev *cdev) 
	if (!funcs)

	if (!funcs)

		return -ENODEV;

		return -ENODEV;





	list_for_each_entry(n, &hidg_func_list, node) {

	list_for_each_entry(iter_n, &hidg_func_list, node) {

		n->fi = usb_get_function_instance("hid");

		iter_n->fi = usb_get_function_instance("hid");

		if (IS_ERR(n->fi)) {

		if (IS_ERR(iter_n->fi)) {

			status = PTR_ERR(n->fi);

			status = PTR_ERR(iter_n->fi);

			n = iter_n;

			goto put;

			goto put;

		}

		}

		hid_opts = container_of(n->fi, struct f_hid_opts, func_inst);

		hid_opts = container_of(iter_n->fi, struct f_hid_opts, func_inst);

		hid_opts->subclass = n->func->subclass;

		hid_opts->subclass = iter_n->func->subclass;

		hid_opts->protocol = n->func->protocol;

		hid_opts->protocol = iter_n->func->protocol;

		hid_opts->report_length = n->func->report_length;

		hid_opts->report_length = iter_n->func->report_length;

		hid_opts->report_desc_length = n->func->report_desc_length;

		hid_opts->report_desc_length = iter_n->func->report_desc_length;

		hid_opts->report_desc = n->func->report_desc;

		hid_opts->report_desc = iter_n->func->report_desc;

	}

	}