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: Lee Jones <joneslee@google.com>
Change-Id: Ia1280f85499621d3fa57f7262b4a2c80f4be7773
Signed-off-by: Lee Jones <joneslee@google.com>
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 7729edd..66885e2 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -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
@@ -1562,7 +1562,7 @@
#ifdef CONFIG_USB_CONFIGFS_F_ACC
if (value < 0)
- value = acc_ctrlrequest(cdev, c);
+ value = acc_ctrlrequest_composite(cdev, c);
#endif
if (value < 0)
diff --git a/drivers/usb/gadget/function/f_accessory.c b/drivers/usb/gadget/function/f_accessory.c
index e444e20..a00fd58 100644
--- a/drivers/usb/gadget/function/f_accessory.c
+++ b/drivers/usb/gadget/function/f_accessory.c
@@ -1076,6 +1076,26 @@
}
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)
