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Commit f563d230 authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Felipe Balbi
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usb: gadget: composite: add req_match method to usb_function 



Non-standard requests can encode the actual interface number in a
non-standard way. For example composite_setup() assumes
that it is w_index && 0xFF, but the printer function encodes the interface
number in a context-dependet way (either w_index or w_index >> 8).
This can lead to such requests being directed to wrong functions.

This patch adds req_match() method to usb_function. Its purpose is to
verify that a given request can be handled by a given function.
If any function within a configuration provides the method and it returns
true, then it is assumed that the right function is found.

If a function uses req_match(), it should try as hard as possible to
determine if the request is meant for it.

If no functions in a configuration provide req_match or none of them
returns true, then fall back to the usual approach.

Signed-off-by: default avatarAndrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 143d53e1

drivers/usb/gadget/composite.c

+5 −1
Original line number Diff line number Diff line
@@ -1758,6 +1758,10 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) 
		 * take such requests too, if that's ever needed:  to work

		 * in config 0, etc.

		 */

		list_for_each_entry(f, &cdev->config->functions, list)

			if (f->req_match && f->req_match(f, ctrl))

				goto try_fun_setup;

		f = NULL;

		switch (ctrl->bRequestType & USB_RECIP_MASK) {

		case USB_RECIP_INTERFACE:

			if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
@@ -1775,7 +1779,7 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) 
				f = NULL;

			break;

		}



try_fun_setup:

		if (f && f->setup)

			value = f->setup(f, ctrl);

		else {

include/linux/usb/composite.h

+3 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ struct usb_os_desc_table { 
 * @disable: (REQUIRED) Indicates the function should be disabled.  Reasons

 *	include host resetting or reconfiguring the gadget, and disconnection.

 * @setup: Used for interface-specific control requests.

 * @req_match: Tests if a given class request can be handled by this function.

 * @suspend: Notifies functions when the host stops sending USB traffic.

 * @resume: Notifies functions when the host restarts USB traffic.

 * @get_status: Returns function status as a reply to
@@ -213,6 +214,8 @@ struct usb_function { 
	void			(*disable)(struct usb_function *);

	int			(*setup)(struct usb_function *,

					const struct usb_ctrlrequest *);

	bool			(*req_match)(struct usb_function *,

					const struct usb_ctrlrequest *);

	void			(*suspend)(struct usb_function *);

	void			(*resume)(struct usb_function *);