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can: skb: unify skb CAN frame identification helpers

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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: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20220912170725.120748-2-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp 2022-09-12 19:07:19 +02:00 committed by Marc Kleine-Budde
parent 1c679f9173
commit 96a7457a14
7 changed files with 45 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/net/can/dev/skb.c
View File

@ -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;
}

12
include/linux/can/skb.h
View File

@ -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 */

50
net/can/af_can.c
View File

@ -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 */

9
net/can/bcm.c
View File

@ -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)
return;
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);

4
net/can/gw.c
View File

@ -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;
}

2
net/can/isotp.c
View File

@ -669,7 +669,7 @@ static void isotp_rcv(struct sk_buff *skb, void *data)
if (cf->len <= CAN_MAX_DLEN) {
isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
} else {
if (skb->len == CANFD_MTU) {
if (can_is_canfd_skb(skb)) {
/* We have a CAN FD frame and CAN_DL is greater than 8:
* Only frames with the SF_DL == 0 ESC value are valid.
*

4
net/can/j1939/main.c
View File

@ -42,6 +42,10 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data)
struct j1939_sk_buff_cb *skcb, *iskcb;
struct can_frame *cf;
/* make sure we only get Classical CAN frames */
if (!can_is_can_skb(iskb))
return;
/* create a copy of the skb
* j1939 only delivers the real data bytes,
* the header goes into sockaddr.