usb: Validate and accept set_configuration properly

Setting the same configuration again should act as a lightweight reset, not be
ignored.  This resulted in data toggle bits not being reset and alternet
settings not being reset.

Further, completely invalid configurations were accepted, when they should have
result in a stall. (Section 9.4.7 of USB 2.0 spec)

fixes Github issue #302

Tested-by: Karl Palsson <karlp@tweak.net.au>

1 files changed, 25 insertions, 5 deletions

diff --git a/lib/usb/usb_standard.c b/lib/usb/usb_standard.c
index 92c89460..0333edea 100644
--- a/lib/usb/usb_standard.c
+++ b/lib/usb/usb_standard.c
@@ -245,18 +245,38 @@ static int usb_standard_set_configuration(usbd_device *usbd_dev,
 					  struct usb_setup_data *req,
 					  uint8_t **buf, uint16_t *len)
 {
-	int i;
+	unsigned i;
+	int found_index = -1;
+	const struct usb_config_descriptor *cfg;
 
 	(void)req;
 	(void)buf;
 	(void)len;
 
-	/* Is this correct, or should we reset alternate settings. */
-	if (req->wValue == usbd_dev->current_config) {
-		return 1;
+	if(req->wValue > 0) {
+		for (i = 0; i < usbd_dev->desc->bNumConfigurations; i++) {
+			if (req->wValue == usbd_dev->config[i].bConfigurationValue) {
+				found_index = i;
+				break;
+			}
+		}
+		if (found_index < 0) {
+			return USBD_REQ_NOTSUPP;
+		}
 	}
 
-	usbd_dev->current_config = req->wValue;
+	usbd_dev->current_config = found_index + 1;
+
+	if (usbd_dev->current_config > 0) {
+		cfg = &usbd_dev->config[usbd_dev->current_config - 1];
+
+		/* reset all alternate settings configuration */
+		for (i = 0; i < cfg->bNumInterfaces; i++) {
+			if (cfg->interface[i].cur_altsetting) {
+				*cfg->interface[i].cur_altsetting = 0;
+			}
+		}
+	}
 
 	/* Reset all endpoints. */
 	usbd_dev->driver->ep_reset(usbd_dev);