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

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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: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220308171818.384491-19-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jakob Koschel 2022-03-08 18:18:10 +01:00 committed by Greg Kroah-Hartman
parent 36f4c25ce3
commit eb6db9ccf6
1 changed files with 12 additions and 11 deletions
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23
drivers/usb/gadget/legacy/hid.c
View file

@ -134,7 +134,7 @@ static int hid_bind(struct usb_composite_dev *cdev)
{
struct usb_gadget *gadget = cdev->gadget;
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;
int status, funcs = 0;
@ -144,18 +144,19 @@ static int hid_bind(struct usb_composite_dev *cdev)
if (!funcs)
return -ENODEV;
list_for_each_entry(n, &hidg_func_list, node) {
n->fi = usb_get_function_instance("hid");
if (IS_ERR(n->fi)) {
status = PTR_ERR(n->fi);
list_for_each_entry(iter_n, &hidg_func_list, node) {
iter_n->fi = usb_get_function_instance("hid");
if (IS_ERR(iter_n->fi)) {
status = PTR_ERR(iter_n->fi);
n = iter_n;
goto put;
}
hid_opts = container_of(n->fi, struct f_hid_opts, func_inst);
hid_opts->subclass = n->func->subclass;
hid_opts->protocol = n->func->protocol;
hid_opts->report_length = n->func->report_length;
hid_opts->report_desc_length = n->func->report_desc_length;
hid_opts->report_desc = n->func->report_desc;
hid_opts = container_of(iter_n->fi, struct f_hid_opts, func_inst);
hid_opts->subclass = iter_n->func->subclass;
hid_opts->protocol = iter_n->func->protocol;
hid_opts->report_length = iter_n->func->report_length;
hid_opts->report_desc_length = iter_n->func->report_desc_length;
hid_opts->report_desc = iter_n->func->report_desc;
}