Commit 6fe9f327 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: gs_usb: gs_usb_receive_bulk_callback(): check actual_length before accessing header 

The driver expects to receive a struct gs_host_frame in
gs_usb_receive_bulk_callback().

Use struct_group to describe the header of the struct gs_host_frame and
check that we have at least received the header before accessing any
members of it.

To resubmit the URB, do not dereference the pointer chain
"dev->parent->hf_size_rx" but use "parent->hf_size_rx" instead. Since
"urb->context" contains "parent", it is always defined, while "dev" is not
defined if the URB it too short.

Fixes: d08e973a ("can: gs_usb: Added support for the GS_USB CAN devices")
Link: https://patch.msgid.link/20251114-gs_usb-fix-usb-callbacks-v1-2-a29b42eacada@pengutronix.de


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 516a0cd1

drivers/net/can/usb/gs_usb.c

+19 −7
Original line number Diff line number Diff line
@@ -262,6 +262,7 @@ struct canfd_quirk { 
} __packed;



struct gs_host_frame {

	struct_group(header,

		u32 echo_id;

		__le32 can_id;
@@ -269,6 +270,7 @@ struct gs_host_frame { 
		u8 channel;

		u8 flags;

		u8 reserved;

	);



	union {

		DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
@@ -576,6 +578,7 @@ 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;

	struct gs_tx_context *txc;

	struct can_frame *cf;

	struct canfd_frame *cfd;
@@ -594,6 +597,15 @@ 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;
@@ -687,7 +699,7 @@ 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);