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Commit e418b27c authored by Lee Jones's avatar Lee Jones
Browse files

ANDROID: usb: f_accessory: Check buffer size when initialised via composite 



When communicating with accessory devices via USBFS, the initialisation
call-stack looks like:

  ConfigFS > Gadget ConfigFS > UDC > Gadget ConfigFS > Composite

Eventually ending up in composite_dev_prepare() where memory for the
data buffer is allocated and initialised.  The default size used for the
allocation is USB_COMP_EP0_BUFSIZ (4k).  When handling bulk transfers,
acc_ctrlrequest() needs to be able to handle buffers up to
BULK_BUFFER_SIZE (16k).  Instead of adding new generic attributes to
'struct usb_request' to track the size of the allocated buffer, we can
simply split off the affected thread of execution to travel via a
knowledgeable abstracted function acc_ctrlrequest_composite() where we
can complete the necessary specific checks.

Bug: 264029575
Signed-off-by: default avatarLee Jones <joneslee@google.com>
Change-Id: Ia1280f85499621d3fa57f7262b4a2c80f4be7773
Signed-off-by: default avatarLee Jones <joneslee@google.com>
parent 8912db25

drivers/usb/gadget/configfs.c

+2 −2
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
#include <linux/usb/ch9.h>



#ifdef CONFIG_USB_CONFIGFS_F_ACC

extern int acc_ctrlrequest(struct usb_composite_dev *cdev,

extern int acc_ctrlrequest_composite(struct usb_composite_dev *cdev,

				const struct usb_ctrlrequest *ctrl);

void acc_disconnect(void);

#endif
@@ -1559,7 +1559,7 @@ static int android_setup(struct usb_gadget *gadget, 


#ifdef CONFIG_USB_CONFIGFS_F_ACC

	if (value < 0)

		value = acc_ctrlrequest(cdev, c);

		value = acc_ctrlrequest_composite(cdev, c);

#endif



	if (value < 0)

drivers/usb/gadget/function/f_accessory.c

+20 −0
Original line number Diff line number Diff line
@@ -1006,6 +1006,26 @@ int acc_ctrlrequest(struct usb_composite_dev *cdev, 
}

EXPORT_SYMBOL_GPL(acc_ctrlrequest);



int acc_ctrlrequest_composite(struct usb_composite_dev *cdev,

			      const struct usb_ctrlrequest *ctrl)

{

	u16 w_length = le16_to_cpu(ctrl->wLength);



	if (w_length > USB_COMP_EP0_BUFSIZ) {

		if (ctrl->bRequestType & USB_DIR_IN) {

			/* Cast away the const, we are going to overwrite on purpose. */

			__le16 *temp = (__le16 *)&ctrl->wLength;



			*temp = cpu_to_le16(USB_COMP_EP0_BUFSIZ);

			w_length = USB_COMP_EP0_BUFSIZ;

		} else {

			return -EINVAL;

		}

	}

	return acc_ctrlrequest(cdev, ctrl);

}

EXPORT_SYMBOL_GPL(acc_ctrlrequest_composite);



static int

__acc_function_bind(struct usb_configuration *c,

			struct usb_function *f, bool configfs)