// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <[email protected]>. All Rights Reserved.
*/
#include "queueing.h"
#include "socket.h"
#include "timers.h"
#include "device.h"
#include "ratelimiter.h"
#include "peer.h"
#include "messages.h"
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_arp.h>
#include <linux/icmp.h>
#include <linux/suspend.h>
#include <net/dst_metadata.h>
#include <net/gso.h>
#include <net/icmp.h>
#include <net/rtnetlink.h>
#include <net/ip_tunnels.h>
#include <net/addrconf.h>
static LIST_HEAD(device_list);
static int wg_open(struct net_device *dev)
{
struct in_device *dev_v4 = __in_dev_get_rtnl(dev);
struct inet6_dev *dev_v6 = __in6_dev_get(dev);
struct wg_device *wg = netdev_priv(dev);
struct wg_peer *peer;
int ret;
if (dev_v4) {
/* At some point we might put this check near the ip_rt_send_
* redirect call of ip_forward in net/ipv4/ip_forward.c, similar
* to the current secpath check.
*/
IN_DEV_CONF_SET(dev_v4, SEND_REDIRECTS, false);
IPV4_DEVCONF_ALL(dev_net(dev), SEND_REDIRECTS) = false;
}
if (dev_v6)
dev_v6->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_NONE;
mutex_lock(&wg->device_update_lock);
ret = wg_socket_init(wg, wg->incoming_port);
if (ret < 0)
goto out;
list_for_each_entry(peer, &wg->peer_list, peer_list) {
wg_packet_send_staged_packets(peer);
if (peer->persistent_keepalive_interval)
wg_packet_send_keepalive(peer);
}
out:
mutex_unlock(&wg->device_update_lock);
return ret;
}
static int wg_pm_notification(struct notifier_block *nb, unsigned long action, void *data)
{
struct wg_device *wg;
struct wg_peer *peer;
/* If the machine is constantly suspending and resuming, as part of
* its normal operation rather than as a somewhat rare event, then we
* don't actually want to clear keys.
*/
if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) ||
IS_ENABLED(CONFIG_PM_USERSPACE_AUTOSLEEP))
return 0;
if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE)
return 0;
rtnl_lock();
list_for_each_entry(wg, &device_list, device_list) {
mutex_lock(&wg->device_update_lock);
list_for_each_entry(peer, &wg->peer_list, peer_list) {
del_timer(&peer->timer_zero_key_material);
wg_noise_handshake_clear(&peer->handshake);
wg_noise_keypairs_clear(&peer->keypairs);
}
mutex_unlock(&wg->device_update_lock);
}
rtnl_unlock();
rcu_barrier();
return 0;
}
static struct notifier_block pm_notifier = { .notifier_call = wg_pm_notification };
static int wg_vm_notification(struct notifier_block *nb, unsigned long action, void *data)
{
struct wg_device *wg;
struct wg_peer *peer;
rtnl_lock();
list_for_each_entry(wg, &device_list, device_list) {
mutex_lock(&wg->device_update_lock);
list_for_each_entry(peer, &wg->peer_list, peer_list)
wg_noise_expire_current_peer_keypairs(peer);
mutex_unlock(&wg->device_update_lock);
}
rtnl_unlock();
return 0;
}
static struct notifier_block vm_notifier = { .notifier_call = wg_vm_notification };
static int wg_stop(struct net_device *dev)
{
struct wg_device *wg = netdev_priv(dev);
struct wg_peer *peer;
struct sk_buff *skb;
mutex_lock(&wg->device_update_lock);
list_for_each_entry(peer, &wg->peer_list, peer_list) {
wg_packet_purge_staged_packets(peer);
wg_timers_stop(peer);
wg_noise_handshake_clear(&peer->handshake);
wg_noise_keypairs_clear(&peer->keypairs);
wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake);
}
mutex_unlock(&wg->device_update_lock);
while ((skb = ptr_ring_consume(&wg->handshake_queue.ring)) != NULL)
kfree_skb(skb);
atomic_set(&wg->handshake_queue_len, 0);
wg_socket_reinit(wg, NULL, NULL);
return 0;
}
static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct wg_device *wg = netdev_priv(dev);
struct sk_buff_head packets;
struct wg_peer *peer;
struct sk_buff *next;
sa_family_t family;
u32 mtu;
int ret;
if (unlikely(!wg_check_packet_protocol(skb))) {
ret = -EPROTONOSUPPORT;
net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name);
goto err;
}
peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb);
if (unlikely(!peer)) {
ret = -ENOKEY;
if (skb->protocol == htons(ETH_P_IP))
net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n",
dev->name, &ip_hdr(skb)->daddr);
else if (skb->protocol == htons(ETH_P_IPV6))
net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n",
dev->name, &ipv6_hdr(skb)->daddr);
goto err_icmp;
}
family = READ_ONCE(peer->endpoint.addr.sa_family);
if (unlikely(family != AF_INET && family != AF_INET6)) {
ret = -EDESTADDRREQ;
net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n",
dev->name, peer->internal_id);
goto err_peer;
}
mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
__skb_queue_head_init(&packets);
if (!skb_is_gso(skb)) {
skb_mark_not_on_list(skb);
} else {
struct sk_buff *segs = skb_gso_segment(skb, 0);
if (IS_ERR(segs)) {
ret = PTR_ERR(segs);
goto err_peer;
}
dev_kfree_skb(skb);
skb = segs;
}
skb_list_walk_safe(skb, skb, next) {
skb_mark_not_on_list(skb);
skb = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
continue;
/* We only need to keep the original dst around for icmp,
* so at this point we're in a position to drop it.
*/
skb_dst_drop(skb);
PACKET_CB(skb)->mtu = mtu;
__skb_queue_tail(&packets, skb);
}
spin_lock_bh(&peer->staged_packet_queue.lock);
/* If the queue is getting too big, we start removing the oldest packets
* until it's small again. We do this before adding the new packet, so
* we don't remove GSO segments that are in excess.
*/
while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) {
dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue));
DEV_STATS_INC(dev, tx_dropped);
}
skb_queue_splice_tail(&packets, &peer->staged_packet_queue);
spin_unlock_bh(&peer->staged_packet_queue.lock);
wg_packet_send_staged_packets(peer);
wg_peer_put(peer);
return NETDEV_TX_OK;
err_peer:
wg_peer_put(peer);
err_icmp:
if (skb->protocol == htons(ETH_P_IP))
icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
else if (skb->protocol == htons(ETH_P_IPV6))
icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
err:
DEV_STATS_INC(dev, tx_errors);
kfree_skb(skb);
return ret;
}
static const struct net_device_ops netdev_ops = {
.ndo_open = wg_open,
.ndo_stop = wg_stop,
.ndo_start_xmit = wg_xmit,
};
static void wg_destruct(struct net_device *dev)
{
struct wg_device *wg = netdev_priv(dev);
rtnl_lock();
list_del(&wg->device_list);
rtnl_unlock();
mutex_lock(&wg->device_update_lock);
rcu_assign_pointer(wg->creating_net, NULL);
wg->incoming_port = 0;
wg_socket_reinit(wg, NULL, NULL);
/* The final references are cleared in the below calls to destroy_workqueue. */
wg_peer_remove_all(wg);
destroy_workqueue(wg->handshake_receive_wq);
destroy_workqueue(wg->handshake_send_wq);
destroy_workqueue(wg->packet_crypt_wq);
wg_packet_queue_free(&wg->handshake_queue, true);
wg_packet_queue_free(&wg->decrypt_queue, false);
wg_packet_queue_free(&wg->encrypt_queue, false);
rcu_barrier(); /* Wait for all the peers to be actually freed. */
wg_ratelimiter_uninit();
memzero_explicit(&wg->static_identity, sizeof(wg->static_identity));
kvfree(wg->index_hashtable);
kvfree(wg->peer_hashtable);
mutex_unlock(&wg->device_update_lock);
pr_debug("%s: Interface destroyed\n", dev->name);
free_netdev(dev);
}
static const struct device_type device_type = { .name = KBUILD_MODNAME };
static void wg_setup(struct net_device *dev)
{
struct wg_device *wg = netdev_priv(dev);
enum { WG_NETDEV_FEATURES = NETIF_F_HW_CSUM | NETIF_F_RXCSUM |
NETIF_F_SG | NETIF_F_GSO |
NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA };
const int overhead = MESSAGE_MINIMUM_LENGTH + sizeof(struct udphdr) +
max(sizeof(struct ipv6hdr), sizeof(struct iphdr));
dev->netdev_ops = &netdev_ops;
dev->header_ops = &ip_tunnel_header_ops;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->needed_headroom = DATA_PACKET_HEAD_ROOM;
dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE);
dev->type = ARPHRD_NONE;
dev->flags = IFF_POINTOPOINT | IFF_NOARP;
dev->priv_flags |= IFF_NO_QUEUE;
dev->lltx = true;
dev->features |= WG_NETDEV_FEATURES;
dev->hw_features |= WG_NETDEV_FEATURES;
dev->hw_enc_features |= WG_NETDEV_FEATURES;
dev->mtu = ETH_DATA_LEN - overhead;
dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead;
dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
SET_NETDEV_DEVTYPE(dev, &device_type);
/* We need to keep the dst around in case of icmp replies. */
netif_keep_dst(dev);
memset(wg, 0, sizeof(*wg));
wg->dev = dev;
}
static int wg_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
struct wg_device *wg = netdev_priv(dev);
int ret = -ENOMEM;
rcu_assign_pointer(wg->creating_net, src_net);
init_rwsem(&wg->static_identity.lock);
mutex_init(&wg->socket_update_lock);
mutex_init(&wg->device_update_lock);
wg_allowedips_init(&wg->peer_allowedips);
wg_cookie_checker_init(&wg->cookie_checker, wg);
INIT_LIST_HEAD(&wg->peer_list);
wg->device_update_gen = 1;
wg->peer_hashtable = wg_pubkey_hashtable_alloc();
if (!wg->peer_hashtable)
return ret;
wg->index_hashtable = wg_index_hashtable_alloc();
if (!wg->index_hashtable)
goto err_free_peer_hashtable;
wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s",
WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name);
if (!wg->handshake_receive_wq)
goto err_free_index_hashtable;
wg->handshake_send_wq = alloc_workqueue("wg-kex-%s",
WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name);
if (!wg->handshake_send_wq)
goto err_destroy_handshake_receive;
wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s",
WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name);
if (!wg->packet_crypt_wq)
goto err_destroy_handshake_send;
ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker,
MAX_QUEUED_PACKETS);
if (ret < 0)
goto err_destroy_packet_crypt;
ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker,
MAX_QUEUED_PACKETS);
if (ret < 0)
goto err_free_encrypt_queue;
ret = wg_packet_queue_init(&wg->handshake_queue, wg_packet_handshake_receive_worker,
MAX_QUEUED_INCOMING_HANDSHAKES);
if (ret < 0)
goto err_free_decrypt_queue;
ret = wg_ratelimiter_init();
if (ret < 0)
goto err_free_handshake_queue;
ret = register_netdevice(dev);
if (ret < 0)
goto err_uninit_ratelimiter;
list_add(&wg->device_list, &device_list);
/* We wait until the end to assign priv_destructor, so that
* register_netdevice doesn't call it for us if it fails.
*/
dev->priv_destructor = wg_destruct;
pr_debug("%s: Interface created\n", dev->name);
return ret;
err_uninit_ratelimiter:
wg_ratelimiter_uninit();
err_free_handshake_queue:
wg_packet_queue_free(&wg->handshake_queue, false);
err_free_decrypt_queue:
wg_packet_queue_free(&wg->decrypt_queue, false);
err_free_encrypt_queue:
wg_packet_queue_free(&wg->encrypt_queue, false);
err_destroy_packet_crypt:
destroy_workqueue(wg->packet_crypt_wq);
err_destroy_handshake_send:
destroy_workqueue(wg->handshake_send_wq);
err_destroy_handshake_receive:
destroy_workqueue(wg->handshake_receive_wq);
err_free_index_hashtable:
kvfree(wg->index_hashtable);
err_free_peer_hashtable:
kvfree(wg->peer_hashtable);
return ret;
}
static struct rtnl_link_ops link_ops __read_mostly = {
.kind = KBUILD_MODNAME,
.priv_size = sizeof(struct wg_device),
.setup = wg_setup,
.newlink = wg_newlink,
};
static void wg_netns_pre_exit(struct net *net)
{
struct wg_device *wg;
struct wg_peer *peer;
rtnl_lock();
list_for_each_entry(wg, &device_list, device_list) {
if (rcu_access_pointer(wg->creating_net) == net) {
pr_debug("%s: Creating namespace exiting\n", wg->dev->name);
netif_carrier_off(wg->dev);
mutex_lock(&wg->device_update_lock);
rcu_assign_pointer(wg->creating_net, NULL);
wg_socket_reinit(wg, NULL, NULL);
list_for_each_entry(peer, &wg->peer_list, peer_list)
wg_socket_clear_peer_endpoint_src(peer);
mutex_unlock(&wg->device_update_lock);
}
}
rtnl_unlock();
}
static struct pernet_operations pernet_ops = {
.pre_exit = wg_netns_pre_exit
};
int __init wg_device_init(void)
{
int ret;
ret = register_pm_notifier(&pm_notifier);
if (ret)
return ret;
ret = register_random_vmfork_notifier(&vm_notifier);
if (ret)
goto error_pm;
ret = register_pernet_device(&pernet_ops);
if (ret)
goto error_vm;
ret = rtnl_link_register(&link_ops);
if (ret)
goto error_pernet;
return 0;
error_pernet:
unregister_pernet_device(&pernet_ops);
error_vm:
unregister_random_vmfork_notifier(&vm_notifier);
error_pm:
unregister_pm_notifier(&pm_notifier);
return ret;
}
void wg_device_uninit(void)
{
rtnl_link_unregister(&link_ops);
unregister_pernet_device(&pernet_ops);
unregister_random_vmfork_notifier(&vm_notifier);
unregister_pm_notifier(&pm_notifier);
rcu_barrier();
}
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