Commit 96a7457a authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
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can: skb: unify skb CAN frame identification helpers 



Replace open coded checks for sk_buffs containing Classical CAN and
CAN FD frame structures as a preparation for CAN XL support.

With the added length check the unintended processing of CAN XL frames
having the CANXL_XLF bit set can be suppressed even when the skb->len
fits to non CAN XL frames.

The CAN_RAW socket needs a rework to use these helpers. Therefore the
use of these helpers is postponed to the CAN_RAW CAN XL integration.

The J1939 protocol gets a check for Classical CAN frames too.

Acked-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20220912170725.120748-2-socketcan@hartkopp.net


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 1c679f91

drivers/net/can/dev/skb.c

+10 −8
Original line number Diff line number Diff line
@@ -299,18 +299,20 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb) 
/* Drop a given socketbuffer if it does not contain a valid CAN frame. */

bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)

{

	const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

	struct can_priv *priv = netdev_priv(dev);



	if (skb->protocol == htons(ETH_P_CAN)) {

		if (unlikely(skb->len != CAN_MTU ||

			     cfd->len > CAN_MAX_DLEN))

	switch (ntohs(skb->protocol)) {

	case ETH_P_CAN:

		if (!can_is_can_skb(skb))

			goto inval_skb;

	} else if (skb->protocol == htons(ETH_P_CANFD)) {

		if (unlikely(skb->len != CANFD_MTU ||

			     cfd->len > CANFD_MAX_DLEN))

		break;



	case ETH_P_CANFD:

		if (!can_is_canfd_skb(skb))

			goto inval_skb;

	} else {

		break;



	default:

		goto inval_skb;

	}

include/linux/can/skb.h

+11 −1
Original line number Diff line number Diff line
@@ -97,10 +97,20 @@ static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb) 
	return nskb;

}



static inline bool can_is_can_skb(const struct sk_buff *skb)

{

	struct can_frame *cf = (struct can_frame *)skb->data;



	/* the CAN specific type of skb is identified by its data length */

	return (skb->len == CAN_MTU && cf->len <= CAN_MAX_DLEN);

}



static inline bool can_is_canfd_skb(const struct sk_buff *skb)

{

	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;



	/* the CAN specific type of skb is identified by its data length */

	return skb->len == CANFD_MTU;

	return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN);

}



#endif /* !_CAN_SKB_H */

net/can/af_can.c

+10 −40
Original line number Diff line number Diff line
@@ -199,27 +199,19 @@ static int can_create(struct net *net, struct socket *sock, int protocol, 
int can_send(struct sk_buff *skb, int loop)

{

	struct sk_buff *newskb = NULL;

	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

	struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;

	int err = -EINVAL;



	if (skb->len == CAN_MTU) {

	if (can_is_can_skb(skb)) {

		skb->protocol = htons(ETH_P_CAN);

		if (unlikely(cfd->len > CAN_MAX_DLEN))

			goto inval_skb;

	} else if (skb->len == CANFD_MTU) {

	} else if (can_is_canfd_skb(skb)) {

		skb->protocol = htons(ETH_P_CANFD);

		if (unlikely(cfd->len > CANFD_MAX_DLEN))

			goto inval_skb;

	} else {

		goto inval_skb;

	}



	/* Make sure the CAN frame can pass the selected CAN netdevice.

	 * As structs can_frame and canfd_frame are similar, we can provide

	 * CAN FD frames to legacy CAN drivers as long as the length is <= 8

	 */

	if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) {

	/* Make sure the CAN frame can pass the selected CAN netdevice. */

	if (unlikely(skb->len > skb->dev->mtu)) {

		err = -EMSGSIZE;

		goto inval_skb;

	}
@@ -678,53 +670,31 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev) 
static int can_rcv(struct sk_buff *skb, struct net_device *dev,

		   struct packet_type *pt, struct net_device *orig_dev)

{

	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;



	if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU)) {

	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_can_skb(skb)))) {

		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",

			     dev->type, skb->len);

		goto free_skb;

	}



	/* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */

	if (unlikely(cfd->len > CAN_MAX_DLEN)) {

		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d, datalen %d\n",

			     dev->type, skb->len, cfd->len);

		goto free_skb;

		kfree_skb(skb);

		return NET_RX_DROP;

	}



	can_receive(skb, dev);

	return NET_RX_SUCCESS;



free_skb:

	kfree_skb(skb);

	return NET_RX_DROP;

}



static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,

		     struct packet_type *pt, struct net_device *orig_dev)

{

	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;



	if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU)) {

	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canfd_skb(skb)))) {

		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",

			     dev->type, skb->len);

		goto free_skb;

	}



	/* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */

	if (unlikely(cfd->len > CANFD_MAX_DLEN)) {

		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d, datalen %d\n",

			     dev->type, skb->len, cfd->len);

		goto free_skb;

		kfree_skb(skb);

		return NET_RX_DROP;

	}



	can_receive(skb, dev);

	return NET_RX_SUCCESS;



free_skb:

	kfree_skb(skb);

	return NET_RX_DROP;

}



/* af_can protocol functions */

net/can/bcm.c

+7 −2
Original line number Diff line number Diff line
@@ -648,8 +648,13 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) 
		return;



	/* make sure to handle the correct frame type (CAN / CAN FD) */

	if (skb->len != op->cfsiz)

	if (op->flags & CAN_FD_FRAME) {

		if (!can_is_canfd_skb(skb))

			return;

	} else {

		if (!can_is_can_skb(skb))

			return;

	}



	/* disable timeout */

	hrtimer_cancel(&op->timer);

net/can/gw.c

+2 −2
Original line number Diff line number Diff line
@@ -463,10 +463,10 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data) 


	/* process strictly Classic CAN or CAN FD frames */

	if (gwj->flags & CGW_FLAGS_CAN_FD) {

		if (skb->len != CANFD_MTU)

		if (!can_is_canfd_skb(skb))

			return;

	} else {

		if (skb->len != CAN_MTU)

		if (!can_is_can_skb(skb))

			return;

	}