Commit faba5860 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: raw: instantly reject disabled 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 now performed on CAN_RAW sockets to give an instant feedback
to the user when writing unsupported CAN frames to the interface or when
the CAN interface is in read-only mode.

Fixes: 1a620a72 ("can: raw: instantly reject unsupported CAN frames")
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20260109144135.8495-4-socketcan@hartkopp.net
[mkl: fix dev reference leak]
Link: https://lore.kernel.org/all/0636c732-2e71-4633-8005-dfa85e1da445@hartkopp.net


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 166e8732

net/can/raw.c

+16 −9
Original line number Diff line number Diff line
@@ -49,8 +49,8 @@ 
#include <linux/if_arp.h>

#include <linux/skbuff.h>

#include <linux/can.h>

#include <linux/can/can-ml.h>

#include <linux/can/core.h>

#include <linux/can/dev.h> /* for can_is_canxl_dev_mtu() */

#include <linux/can/skb.h>

#include <linux/can/raw.h>

#include <net/sock.h>
@@ -892,20 +892,21 @@ 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 unsigned int raw_check_txframe(struct raw_sock *ro, struct sk_buff *skb,

				      struct net_device *dev)

{

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

	if (can_is_can_skb(skb))

	/* Classical CAN */

	if (can_is_can_skb(skb) && can_cap_enabled(dev, CAN_CAP_CC))

		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)))

	    can_cap_enabled(dev, CAN_CAP_FD))

		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))

	    can_cap_enabled(dev, CAN_CAP_XL))

		return CANXL_MTU;



	return 0;
@@ -944,6 +945,12 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
	if (!dev)

		return -ENXIO;



	/* no sending on a CAN device in read-only mode */

	if (can_cap_enabled(dev, CAN_CAP_RO)) {

		err = -EACCES;

		goto put_dev;

	}



	skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),

				  msg->msg_flags & MSG_DONTWAIT, &err);

	if (!skb)
@@ -961,7 +968,7 @@ 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;