Commit 1a620a72 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: raw: instantly reject unsupported CAN frames 



For real CAN interfaces the CAN_CTRLMODE_FD and CAN_CTRLMODE_XL control
modes indicate whether an interface can handle those CAN FD/XL frames.

In the case a CAN XL interface is configured in CANXL-only mode with
disabled error-signalling neither CAN CC nor CAN FD frames can be sent.

The checks are performed on CAN_RAW sockets to give an instant feedback
to the user when writing unsupported CAN frames to the interface.

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20251126-canxl-v8-16-e7e3eb74f889@pengutronix.de


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 816cf430

net/can/raw.c

+46 −8
Original line number Diff line number Diff line
@@ -892,20 +892,58 @@ static void raw_put_canxl_vcid(struct raw_sock *ro, struct sk_buff *skb) 
	}

}



static unsigned int raw_check_txframe(struct raw_sock *ro, struct sk_buff *skb, int mtu)

static inline bool raw_dev_cc_enabled(struct net_device *dev,

				      struct can_priv *priv)

{

	/* Classical CAN -> no checks for flags and device capabilities */

	if (can_is_can_skb(skb))

	/* The CANXL-only mode disables error-signalling on the CAN bus

	 * which is needed to send CAN CC/FD frames

	 */

	if (priv)

		return !can_dev_in_xl_only_mode(priv);



	/* virtual CAN interfaces always support CAN CC */

	return true;

}



static inline bool raw_dev_fd_enabled(struct net_device *dev,

				      struct can_priv *priv)

{

	/* check FD ctrlmode on real CAN interfaces */

	if (priv)

		return (priv->ctrlmode & CAN_CTRLMODE_FD);



	/* check MTU for virtual CAN FD interfaces */

	return (READ_ONCE(dev->mtu) >= CANFD_MTU);

}



static inline bool raw_dev_xl_enabled(struct net_device *dev,

				      struct can_priv *priv)

{

	/* check XL ctrlmode on real CAN interfaces */

	if (priv)

		return (priv->ctrlmode & CAN_CTRLMODE_XL);



	/* check MTU for virtual CAN XL interfaces */

	return can_is_canxl_dev_mtu(READ_ONCE(dev->mtu));

}



static unsigned int raw_check_txframe(struct raw_sock *ro, struct sk_buff *skb,

				      struct net_device *dev)

{

	struct can_priv *priv = safe_candev_priv(dev);



	/* Classical CAN */

	if (can_is_can_skb(skb) && raw_dev_cc_enabled(dev, priv))

		return CAN_MTU;



	/* CAN FD -> needs to be enabled and a CAN FD or CAN XL device */

	/* CAN FD */

	if (ro->fd_frames && can_is_canfd_skb(skb) &&

	    (mtu == CANFD_MTU || can_is_canxl_dev_mtu(mtu)))

	    raw_dev_fd_enabled(dev, priv))

		return CANFD_MTU;



	/* CAN XL -> needs to be enabled and a CAN XL device */

	/* CAN XL */

	if (ro->xl_frames && can_is_canxl_skb(skb) &&

	    can_is_canxl_dev_mtu(mtu))

	    raw_dev_xl_enabled(dev, priv))

		return CANXL_MTU;



	return 0;
@@ -961,7 +999,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
	err = -EINVAL;



	/* check for valid CAN (CC/FD/XL) frame content */

	txmtu = raw_check_txframe(ro, skb, READ_ONCE(dev->mtu));

	txmtu = raw_check_txframe(ro, skb, dev);

	if (!txmtu)

		goto free_skb;