summaryrefslogtreecommitdiff
path: root/drivers/net/wireguard/device.c
blob: a8f151b1b5fab52d061efdb3e49975076c93d3ac (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. 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/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;
}

#ifdef CONFIG_PM_SLEEP
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_ANDROID))
		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 };
#endif

static int wg_stop(struct net_device *dev)
{
	struct wg_device *wg = netdev_priv(dev);
	struct wg_peer *peer;

	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);
	skb_queue_purge(&wg->incoming_handshakes);
	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;
	}

	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_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 (unlikely(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.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:
	++dev->stats.tx_errors;
	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);
	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,
	.ndo_get_stats64	= ip_tunnel_get_stats64
};

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->decrypt_queue, true);
	wg_packet_queue_free(&wg->encrypt_queue, true);
	rcu_barrier(); /* Wait for all the peers to be actually freed. */
	wg_ratelimiter_uninit();
	memzero_explicit(&wg->static_identity, sizeof(wg->static_identity));
	skb_queue_purge(&wg->incoming_handshakes);
	free_percpu(dev->tstats);
	free_percpu(wg->incoming_handshakes_worker);
	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->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->features |= NETIF_F_LLTX;
	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;

	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);
	skb_queue_head_init(&wg->incoming_handshakes);
	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;

	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
	if (!dev->tstats)
		goto err_free_index_hashtable;

	wg->incoming_handshakes_worker =
		wg_packet_percpu_multicore_worker_alloc(
				wg_packet_handshake_receive_worker, wg);
	if (!wg->incoming_handshakes_worker)
		goto err_free_tstats;

	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_incoming_handshakes;

	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,
				   true, MAX_QUEUED_PACKETS);
	if (ret < 0)
		goto err_destroy_packet_crypt;

	ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker,
				   true, MAX_QUEUED_PACKETS);
	if (ret < 0)
		goto err_free_encrypt_queue;

	ret = wg_ratelimiter_init();
	if (ret < 0)
		goto err_free_decrypt_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_decrypt_queue:
	wg_packet_queue_free(&wg->decrypt_queue, true);
err_free_encrypt_queue:
	wg_packet_queue_free(&wg->encrypt_queue, true);
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_incoming_handshakes:
	free_percpu(wg->incoming_handshakes_worker);
err_free_tstats:
	free_percpu(dev->tstats);
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;

	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);
			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;

#ifdef CONFIG_PM_SLEEP
	ret = register_pm_notifier(&pm_notifier);
	if (ret)
		return ret;
#endif

	ret = register_pernet_device(&pernet_ops);
	if (ret)
		goto error_pm;

	ret = rtnl_link_register(&link_ops);
	if (ret)
		goto error_pernet;

	return 0;

error_pernet:
	unregister_pernet_device(&pernet_ops);
error_pm:
#ifdef CONFIG_PM_SLEEP
	unregister_pm_notifier(&pm_notifier);
#endif
	return ret;
}

void wg_device_uninit(void)
{
	rtnl_link_unregister(&link_ops);
	unregister_pernet_device(&pernet_ops);
#ifdef CONFIG_PM_SLEEP
	unregister_pm_notifier(&pm_notifier);
#endif
	rcu_barrier();
}