Merge patch series "can: gs_usb: fix USB bulk in and out callbacks"

Marc Kleine-Budde <mkl@pengutronix.de> says:

The bulk-out callback gs_usb_xmit_callback() does not take care of the
cleanup of failed transfers of URBs. The 1st patch adds the missing
cleanup.

The bulk-in callback gs_usb_receive_bulk_callback() accesses the buffer of
the URB without checking how much data has actually been received. The last
2 patches fix this problem.

Link: https://patch.msgid.link/20251114-gs_usb-fix-usb-callbacks-v1-0-a29b42eacada@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Author: marckleinebudde

drivers/net/can/usb/gs_usb.c

@@ -261,14 +261,21 @@ struct canfd_quirk {
 	u8 quirk;
 } __packed;
 
+/* struct gs_host_frame::echo_id == GS_HOST_FRAME_ECHO_ID_RX indicates
+ * a regular RX'ed CAN frame
+ */
+#define GS_HOST_FRAME_ECHO_ID_RX 0xffffffff
+
 struct gs_host_frame {
-	u32 echo_id;
-	__le32 can_id;
+	struct_group(header,
+		u32 echo_id;
+		__le32 can_id;
 
-	u8 can_dlc;
-	u8 channel;
-	u8 flags;
-	u8 reserved;
+		u8 can_dlc;
+		u8 channel;
+		u8 flags;
+		u8 reserved;
+	);
 
 	union {
 		DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
@@ -568,6 +575,37 @@ gs_usb_get_echo_skb(struct gs_can *dev, struct sk_buff *skb,
 	return len;
 }
 
+static unsigned int
+gs_usb_get_minimum_rx_length(const struct gs_can *dev, const struct gs_host_frame *hf,
+			     unsigned int *data_length_p)
+{
+	unsigned int minimum_length, data_length = 0;
+
+	if (hf->flags & GS_CAN_FLAG_FD) {
+		if (hf->echo_id == GS_HOST_FRAME_ECHO_ID_RX)
+			data_length = can_fd_dlc2len(hf->can_dlc);
+
+		if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
+			/* timestamp follows data field of max size */
+			minimum_length = struct_size(hf, canfd_ts, 1);
+		else
+			minimum_length = sizeof(hf->header) + data_length;
+	} else {
+		if (hf->echo_id == GS_HOST_FRAME_ECHO_ID_RX &&
+		    !(hf->can_id & cpu_to_le32(CAN_RTR_FLAG)))
+			data_length = can_cc_dlc2len(hf->can_dlc);
+
+		if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
+			/* timestamp follows data field of max size */
+			minimum_length = struct_size(hf, classic_can_ts, 1);
+		else
+			minimum_length = sizeof(hf->header) + data_length;
+	}
+
+	*data_length_p = data_length;
+	return minimum_length;
+}
+
 static void gs_usb_receive_bulk_callback(struct urb *urb)
 {
 	struct gs_usb *parent = urb->context;
@@ -576,6 +614,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	int rc;
 	struct net_device_stats *stats;
 	struct gs_host_frame *hf = urb->transfer_buffer;
+	unsigned int minimum_length, data_length;
 	struct gs_tx_context *txc;
 	struct can_frame *cf;
 	struct canfd_frame *cfd;
@@ -594,6 +633,15 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 		return;
 	}
 
+	minimum_length = sizeof(hf->header);
+	if (urb->actual_length < minimum_length) {
+		dev_err_ratelimited(&parent->udev->dev,
+				    "short read (actual_length=%u, minimum_length=%u)\n",
+				    urb->actual_length, minimum_length);
+
+		goto resubmit_urb;
+	}
+
 	/* device reports out of range channel id */
 	if (hf->channel >= parent->channel_cnt)
 		goto device_detach;
@@ -609,20 +657,33 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	if (!netif_running(netdev))
 		goto resubmit_urb;
 
-	if (hf->echo_id == -1) { /* normal rx */
+	minimum_length = gs_usb_get_minimum_rx_length(dev, hf, &data_length);
+	if (urb->actual_length < minimum_length) {
+		stats->rx_errors++;
+		stats->rx_length_errors++;
+
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "short read (actual_length=%u, minimum_length=%u)\n",
+				   urb->actual_length, minimum_length);
+
+		goto resubmit_urb;
+	}
+
+	if (hf->echo_id == GS_HOST_FRAME_ECHO_ID_RX) { /* normal rx */
 		if (hf->flags & GS_CAN_FLAG_FD) {
 			skb = alloc_canfd_skb(netdev, &cfd);
 			if (!skb)
 				return;
 
 			cfd->can_id = le32_to_cpu(hf->can_id);
-			cfd->len = can_fd_dlc2len(hf->can_dlc);
+			cfd->len = data_length;
 			if (hf->flags & GS_CAN_FLAG_BRS)
 				cfd->flags |= CANFD_BRS;
 			if (hf->flags & GS_CAN_FLAG_ESI)
 				cfd->flags |= CANFD_ESI;
 
-			memcpy(cfd->data, hf->canfd->data, cfd->len);
+			memcpy(cfd->data, hf->canfd->data, data_length);
 		} else {
 			skb = alloc_can_skb(netdev, &cf);
 			if (!skb)
@@ -631,7 +692,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 			cf->can_id = le32_to_cpu(hf->can_id);
 			can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);
 
-			memcpy(cf->data, hf->classic_can->data, 8);
+			memcpy(cf->data, hf->classic_can->data, data_length);
 
 			/* ERROR frames tell us information about the controller */
 			if (le32_to_cpu(hf->can_id) & CAN_ERR_FLAG)
@@ -687,7 +748,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 resubmit_urb:
 	usb_fill_bulk_urb(urb, parent->udev,
 			  parent->pipe_in,
-			  hf, dev->parent->hf_size_rx,
+			  hf, parent->hf_size_rx,
 			  gs_usb_receive_bulk_callback, parent);
 
 	rc = usb_submit_urb(urb, GFP_ATOMIC);
@@ -750,8 +811,21 @@ static void gs_usb_xmit_callback(struct urb *urb)
 	struct gs_can *dev = txc->dev;
 	struct net_device *netdev = dev->netdev;
 
-	if (urb->status)
-		netdev_info(netdev, "usb xmit fail %u\n", txc->echo_id);
+	if (!urb->status)
+		return;
+
+	if (urb->status != -ESHUTDOWN && net_ratelimit())
+		netdev_info(netdev, "failed to xmit URB %u: %pe\n",
+			    txc->echo_id, ERR_PTR(urb->status));
+
+	netdev->stats.tx_dropped++;
+	netdev->stats.tx_errors++;
+
+	can_free_echo_skb(netdev, txc->echo_id, NULL);
+	gs_free_tx_context(txc);
+	atomic_dec(&dev->active_tx_urbs);
+
+	netif_wake_queue(netdev);
 }
 
 static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,