mirror of
https://github.com/torvalds/linux.git
synced 2024-12-15 07:33:56 +00:00
4e096a1886
Since20dd3850bc
("can: Speed up CAN frame receiption by using ml_priv") the CAN framework uses per device specific data in the AF_CAN protocol. For this purpose the struct net_device->ml_priv is used. Later the ml_priv usage in CAN was extended for other users, one of them being CAN_J1939. Later in the kernel ml_priv was converted to an union, used by other drivers. E.g. the tun driver started storing it's stats pointer. Since tun devices can claim to be a CAN device, CAN specific protocols will wrongly interpret this pointer, which will cause system crashes. Mostly this issue is visible in the CAN_J1939 stack. To fix this issue, we request a dedicated CAN pointer within the net_device struct. Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com Fixes:20dd3850bc
("can: Speed up CAN frame receiption by using ml_priv") Fixes:ffd956eef6
("can: introduce CAN midlayer private and allocate it automatically") Fixes:9d71dd0c70
("can: add support of SAE J1939 protocol") Fixes:497a5757ce
("tun: switch to net core provided statistics counters") Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Link: https://lore.kernel.org/r/20210223070127.4538-1-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
315 lines
7.1 KiB
C
315 lines
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* vxcan.c - Virtual CAN Tunnel for cross namespace communication
|
|
*
|
|
* This code is derived from drivers/net/can/vcan.c for the virtual CAN
|
|
* specific parts and from drivers/net/veth.c to implement the netlink API
|
|
* for network interface pairs in a common and established way.
|
|
*
|
|
* Copyright (c) 2017 Oliver Hartkopp <socketcan@hartkopp.net>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/if_arp.h>
|
|
#include <linux/if_ether.h>
|
|
#include <linux/can.h>
|
|
#include <linux/can/dev.h>
|
|
#include <linux/can/skb.h>
|
|
#include <linux/can/vxcan.h>
|
|
#include <linux/can/can-ml.h>
|
|
#include <linux/slab.h>
|
|
#include <net/rtnetlink.h>
|
|
|
|
#define DRV_NAME "vxcan"
|
|
|
|
MODULE_DESCRIPTION("Virtual CAN Tunnel");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
|
|
MODULE_ALIAS_RTNL_LINK(DRV_NAME);
|
|
|
|
struct vxcan_priv {
|
|
struct net_device __rcu *peer;
|
|
};
|
|
|
|
static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev)
|
|
{
|
|
struct vxcan_priv *priv = netdev_priv(dev);
|
|
struct net_device *peer;
|
|
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
|
|
struct net_device_stats *peerstats, *srcstats = &dev->stats;
|
|
u8 len;
|
|
|
|
if (can_dropped_invalid_skb(dev, skb))
|
|
return NETDEV_TX_OK;
|
|
|
|
rcu_read_lock();
|
|
peer = rcu_dereference(priv->peer);
|
|
if (unlikely(!peer)) {
|
|
kfree_skb(skb);
|
|
dev->stats.tx_dropped++;
|
|
goto out_unlock;
|
|
}
|
|
|
|
skb = can_create_echo_skb(skb);
|
|
if (!skb)
|
|
goto out_unlock;
|
|
|
|
/* reset CAN GW hop counter */
|
|
skb->csum_start = 0;
|
|
skb->pkt_type = PACKET_BROADCAST;
|
|
skb->dev = peer;
|
|
skb->ip_summed = CHECKSUM_UNNECESSARY;
|
|
|
|
len = cfd->len;
|
|
if (netif_rx_ni(skb) == NET_RX_SUCCESS) {
|
|
srcstats->tx_packets++;
|
|
srcstats->tx_bytes += len;
|
|
peerstats = &peer->stats;
|
|
peerstats->rx_packets++;
|
|
peerstats->rx_bytes += len;
|
|
}
|
|
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
return NETDEV_TX_OK;
|
|
}
|
|
|
|
|
|
static int vxcan_open(struct net_device *dev)
|
|
{
|
|
struct vxcan_priv *priv = netdev_priv(dev);
|
|
struct net_device *peer = rtnl_dereference(priv->peer);
|
|
|
|
if (!peer)
|
|
return -ENOTCONN;
|
|
|
|
if (peer->flags & IFF_UP) {
|
|
netif_carrier_on(dev);
|
|
netif_carrier_on(peer);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int vxcan_close(struct net_device *dev)
|
|
{
|
|
struct vxcan_priv *priv = netdev_priv(dev);
|
|
struct net_device *peer = rtnl_dereference(priv->peer);
|
|
|
|
netif_carrier_off(dev);
|
|
if (peer)
|
|
netif_carrier_off(peer);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int vxcan_get_iflink(const struct net_device *dev)
|
|
{
|
|
struct vxcan_priv *priv = netdev_priv(dev);
|
|
struct net_device *peer;
|
|
int iflink;
|
|
|
|
rcu_read_lock();
|
|
peer = rcu_dereference(priv->peer);
|
|
iflink = peer ? peer->ifindex : 0;
|
|
rcu_read_unlock();
|
|
|
|
return iflink;
|
|
}
|
|
|
|
static int vxcan_change_mtu(struct net_device *dev, int new_mtu)
|
|
{
|
|
/* Do not allow changing the MTU while running */
|
|
if (dev->flags & IFF_UP)
|
|
return -EBUSY;
|
|
|
|
if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
|
|
return -EINVAL;
|
|
|
|
dev->mtu = new_mtu;
|
|
return 0;
|
|
}
|
|
|
|
static const struct net_device_ops vxcan_netdev_ops = {
|
|
.ndo_open = vxcan_open,
|
|
.ndo_stop = vxcan_close,
|
|
.ndo_start_xmit = vxcan_xmit,
|
|
.ndo_get_iflink = vxcan_get_iflink,
|
|
.ndo_change_mtu = vxcan_change_mtu,
|
|
};
|
|
|
|
static void vxcan_setup(struct net_device *dev)
|
|
{
|
|
struct can_ml_priv *can_ml;
|
|
|
|
dev->type = ARPHRD_CAN;
|
|
dev->mtu = CANFD_MTU;
|
|
dev->hard_header_len = 0;
|
|
dev->addr_len = 0;
|
|
dev->tx_queue_len = 0;
|
|
dev->flags = (IFF_NOARP|IFF_ECHO);
|
|
dev->netdev_ops = &vxcan_netdev_ops;
|
|
dev->needs_free_netdev = true;
|
|
|
|
can_ml = netdev_priv(dev) + ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN);
|
|
can_set_ml_priv(dev, can_ml);
|
|
}
|
|
|
|
/* forward declaration for rtnl_create_link() */
|
|
static struct rtnl_link_ops vxcan_link_ops;
|
|
|
|
static int vxcan_newlink(struct net *net, struct net_device *dev,
|
|
struct nlattr *tb[], struct nlattr *data[],
|
|
struct netlink_ext_ack *extack)
|
|
{
|
|
struct vxcan_priv *priv;
|
|
struct net_device *peer;
|
|
struct net *peer_net;
|
|
|
|
struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb;
|
|
char ifname[IFNAMSIZ];
|
|
unsigned char name_assign_type;
|
|
struct ifinfomsg *ifmp = NULL;
|
|
int err;
|
|
|
|
/* register peer device */
|
|
if (data && data[VXCAN_INFO_PEER]) {
|
|
struct nlattr *nla_peer;
|
|
|
|
nla_peer = data[VXCAN_INFO_PEER];
|
|
ifmp = nla_data(nla_peer);
|
|
err = rtnl_nla_parse_ifla(peer_tb,
|
|
nla_data(nla_peer) +
|
|
sizeof(struct ifinfomsg),
|
|
nla_len(nla_peer) -
|
|
sizeof(struct ifinfomsg),
|
|
NULL);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
tbp = peer_tb;
|
|
}
|
|
|
|
if (ifmp && tbp[IFLA_IFNAME]) {
|
|
nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
|
|
name_assign_type = NET_NAME_USER;
|
|
} else {
|
|
snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
|
|
name_assign_type = NET_NAME_ENUM;
|
|
}
|
|
|
|
peer_net = rtnl_link_get_net(net, tbp);
|
|
if (IS_ERR(peer_net))
|
|
return PTR_ERR(peer_net);
|
|
|
|
peer = rtnl_create_link(peer_net, ifname, name_assign_type,
|
|
&vxcan_link_ops, tbp, extack);
|
|
if (IS_ERR(peer)) {
|
|
put_net(peer_net);
|
|
return PTR_ERR(peer);
|
|
}
|
|
|
|
if (ifmp && dev->ifindex)
|
|
peer->ifindex = ifmp->ifi_index;
|
|
|
|
err = register_netdevice(peer);
|
|
put_net(peer_net);
|
|
peer_net = NULL;
|
|
if (err < 0) {
|
|
free_netdev(peer);
|
|
return err;
|
|
}
|
|
|
|
netif_carrier_off(peer);
|
|
|
|
err = rtnl_configure_link(peer, ifmp);
|
|
if (err < 0)
|
|
goto unregister_network_device;
|
|
|
|
/* register first device */
|
|
if (tb[IFLA_IFNAME])
|
|
nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
|
|
else
|
|
snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
|
|
|
|
err = register_netdevice(dev);
|
|
if (err < 0)
|
|
goto unregister_network_device;
|
|
|
|
netif_carrier_off(dev);
|
|
|
|
/* cross link the device pair */
|
|
priv = netdev_priv(dev);
|
|
rcu_assign_pointer(priv->peer, peer);
|
|
|
|
priv = netdev_priv(peer);
|
|
rcu_assign_pointer(priv->peer, dev);
|
|
|
|
return 0;
|
|
|
|
unregister_network_device:
|
|
unregister_netdevice(peer);
|
|
return err;
|
|
}
|
|
|
|
static void vxcan_dellink(struct net_device *dev, struct list_head *head)
|
|
{
|
|
struct vxcan_priv *priv;
|
|
struct net_device *peer;
|
|
|
|
priv = netdev_priv(dev);
|
|
peer = rtnl_dereference(priv->peer);
|
|
|
|
/* Note : dellink() is called from default_device_exit_batch(),
|
|
* before a rcu_synchronize() point. The devices are guaranteed
|
|
* not being freed before one RCU grace period.
|
|
*/
|
|
RCU_INIT_POINTER(priv->peer, NULL);
|
|
unregister_netdevice_queue(dev, head);
|
|
|
|
if (peer) {
|
|
priv = netdev_priv(peer);
|
|
RCU_INIT_POINTER(priv->peer, NULL);
|
|
unregister_netdevice_queue(peer, head);
|
|
}
|
|
}
|
|
|
|
static const struct nla_policy vxcan_policy[VXCAN_INFO_MAX + 1] = {
|
|
[VXCAN_INFO_PEER] = { .len = sizeof(struct ifinfomsg) },
|
|
};
|
|
|
|
static struct net *vxcan_get_link_net(const struct net_device *dev)
|
|
{
|
|
struct vxcan_priv *priv = netdev_priv(dev);
|
|
struct net_device *peer = rtnl_dereference(priv->peer);
|
|
|
|
return peer ? dev_net(peer) : dev_net(dev);
|
|
}
|
|
|
|
static struct rtnl_link_ops vxcan_link_ops = {
|
|
.kind = DRV_NAME,
|
|
.priv_size = ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN) + sizeof(struct can_ml_priv),
|
|
.setup = vxcan_setup,
|
|
.newlink = vxcan_newlink,
|
|
.dellink = vxcan_dellink,
|
|
.policy = vxcan_policy,
|
|
.maxtype = VXCAN_INFO_MAX,
|
|
.get_link_net = vxcan_get_link_net,
|
|
};
|
|
|
|
static __init int vxcan_init(void)
|
|
{
|
|
pr_info("vxcan: Virtual CAN Tunnel driver\n");
|
|
|
|
return rtnl_link_register(&vxcan_link_ops);
|
|
}
|
|
|
|
static __exit void vxcan_exit(void)
|
|
{
|
|
rtnl_link_unregister(&vxcan_link_ops);
|
|
}
|
|
|
|
module_init(vxcan_init);
|
|
module_exit(vxcan_exit);
|