1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. 4 */ 5 6 #include "queueing.h" 7 #include "socket.h" 8 #include "timers.h" 9 #include "device.h" 10 #include "ratelimiter.h" 11 #include "peer.h" 12 #include "messages.h" 13 14 #include <linux/module.h> 15 #include <linux/rtnetlink.h> 16 #include <linux/inet.h> 17 #include <linux/netdevice.h> 18 #include <linux/inetdevice.h> 19 #include <linux/if_arp.h> 20 #include <linux/icmp.h> 21 #include <linux/suspend.h> 22 #include <net/icmp.h> 23 #include <net/rtnetlink.h> 24 #include <net/ip_tunnels.h> 25 #include <net/addrconf.h> 26 27 static LIST_HEAD(device_list); 28 29 static int wg_open(struct net_device *dev) 30 { 31 struct in_device *dev_v4 = __in_dev_get_rtnl(dev); 32 struct inet6_dev *dev_v6 = __in6_dev_get(dev); 33 struct wg_device *wg = netdev_priv(dev); 34 struct wg_peer *peer; 35 int ret; 36 37 if (dev_v4) { 38 /* At some point we might put this check near the ip_rt_send_ 39 * redirect call of ip_forward in net/ipv4/ip_forward.c, similar 40 * to the current secpath check. 41 */ 42 IN_DEV_CONF_SET(dev_v4, SEND_REDIRECTS, false); 43 IPV4_DEVCONF_ALL(dev_net(dev), SEND_REDIRECTS) = false; 44 } 45 if (dev_v6) 46 dev_v6->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_NONE; 47 48 ret = wg_socket_init(wg, wg->incoming_port); 49 if (ret < 0) 50 return ret; 51 mutex_lock(&wg->device_update_lock); 52 list_for_each_entry(peer, &wg->peer_list, peer_list) { 53 wg_packet_send_staged_packets(peer); 54 if (peer->persistent_keepalive_interval) 55 wg_packet_send_keepalive(peer); 56 } 57 mutex_unlock(&wg->device_update_lock); 58 return 0; 59 } 60 61 #ifdef CONFIG_PM_SLEEP 62 static int wg_pm_notification(struct notifier_block *nb, unsigned long action, 63 void *data) 64 { 65 struct wg_device *wg; 66 struct wg_peer *peer; 67 68 /* If the machine is constantly suspending and resuming, as part of 69 * its normal operation rather than as a somewhat rare event, then we 70 * don't actually want to clear keys. 71 */ 72 if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || IS_ENABLED(CONFIG_ANDROID)) 73 return 0; 74 75 if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE) 76 return 0; 77 78 rtnl_lock(); 79 list_for_each_entry(wg, &device_list, device_list) { 80 mutex_lock(&wg->device_update_lock); 81 list_for_each_entry(peer, &wg->peer_list, peer_list) { 82 del_timer(&peer->timer_zero_key_material); 83 wg_noise_handshake_clear(&peer->handshake); 84 wg_noise_keypairs_clear(&peer->keypairs); 85 } 86 mutex_unlock(&wg->device_update_lock); 87 } 88 rtnl_unlock(); 89 rcu_barrier(); 90 return 0; 91 } 92 93 static struct notifier_block pm_notifier = { .notifier_call = wg_pm_notification }; 94 #endif 95 96 static int wg_stop(struct net_device *dev) 97 { 98 struct wg_device *wg = netdev_priv(dev); 99 struct wg_peer *peer; 100 101 mutex_lock(&wg->device_update_lock); 102 list_for_each_entry(peer, &wg->peer_list, peer_list) { 103 wg_packet_purge_staged_packets(peer); 104 wg_timers_stop(peer); 105 wg_noise_handshake_clear(&peer->handshake); 106 wg_noise_keypairs_clear(&peer->keypairs); 107 wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake); 108 } 109 mutex_unlock(&wg->device_update_lock); 110 skb_queue_purge(&wg->incoming_handshakes); 111 wg_socket_reinit(wg, NULL, NULL); 112 return 0; 113 } 114 115 static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev) 116 { 117 struct wg_device *wg = netdev_priv(dev); 118 struct sk_buff_head packets; 119 struct wg_peer *peer; 120 struct sk_buff *next; 121 sa_family_t family; 122 u32 mtu; 123 int ret; 124 125 if (unlikely(!wg_check_packet_protocol(skb))) { 126 ret = -EPROTONOSUPPORT; 127 net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name); 128 goto err; 129 } 130 131 peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb); 132 if (unlikely(!peer)) { 133 ret = -ENOKEY; 134 if (skb->protocol == htons(ETH_P_IP)) 135 net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n", 136 dev->name, &ip_hdr(skb)->daddr); 137 else if (skb->protocol == htons(ETH_P_IPV6)) 138 net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n", 139 dev->name, &ipv6_hdr(skb)->daddr); 140 goto err; 141 } 142 143 family = READ_ONCE(peer->endpoint.addr.sa_family); 144 if (unlikely(family != AF_INET && family != AF_INET6)) { 145 ret = -EDESTADDRREQ; 146 net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n", 147 dev->name, peer->internal_id); 148 goto err_peer; 149 } 150 151 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; 152 153 __skb_queue_head_init(&packets); 154 if (!skb_is_gso(skb)) { 155 skb_mark_not_on_list(skb); 156 } else { 157 struct sk_buff *segs = skb_gso_segment(skb, 0); 158 159 if (unlikely(IS_ERR(segs))) { 160 ret = PTR_ERR(segs); 161 goto err_peer; 162 } 163 dev_kfree_skb(skb); 164 skb = segs; 165 } 166 167 skb_list_walk_safe(skb, skb, next) { 168 skb_mark_not_on_list(skb); 169 170 skb = skb_share_check(skb, GFP_ATOMIC); 171 if (unlikely(!skb)) 172 continue; 173 174 /* We only need to keep the original dst around for icmp, 175 * so at this point we're in a position to drop it. 176 */ 177 skb_dst_drop(skb); 178 179 PACKET_CB(skb)->mtu = mtu; 180 181 __skb_queue_tail(&packets, skb); 182 } 183 184 spin_lock_bh(&peer->staged_packet_queue.lock); 185 /* If the queue is getting too big, we start removing the oldest packets 186 * until it's small again. We do this before adding the new packet, so 187 * we don't remove GSO segments that are in excess. 188 */ 189 while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) { 190 dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue)); 191 ++dev->stats.tx_dropped; 192 } 193 skb_queue_splice_tail(&packets, &peer->staged_packet_queue); 194 spin_unlock_bh(&peer->staged_packet_queue.lock); 195 196 wg_packet_send_staged_packets(peer); 197 198 wg_peer_put(peer); 199 return NETDEV_TX_OK; 200 201 err_peer: 202 wg_peer_put(peer); 203 err: 204 ++dev->stats.tx_errors; 205 if (skb->protocol == htons(ETH_P_IP)) 206 icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 207 else if (skb->protocol == htons(ETH_P_IPV6)) 208 icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0); 209 kfree_skb(skb); 210 return ret; 211 } 212 213 static const struct net_device_ops netdev_ops = { 214 .ndo_open = wg_open, 215 .ndo_stop = wg_stop, 216 .ndo_start_xmit = wg_xmit, 217 .ndo_get_stats64 = ip_tunnel_get_stats64 218 }; 219 220 static void wg_destruct(struct net_device *dev) 221 { 222 struct wg_device *wg = netdev_priv(dev); 223 224 rtnl_lock(); 225 list_del(&wg->device_list); 226 rtnl_unlock(); 227 mutex_lock(&wg->device_update_lock); 228 wg->incoming_port = 0; 229 wg_socket_reinit(wg, NULL, NULL); 230 /* The final references are cleared in the below calls to destroy_workqueue. */ 231 wg_peer_remove_all(wg); 232 destroy_workqueue(wg->handshake_receive_wq); 233 destroy_workqueue(wg->handshake_send_wq); 234 destroy_workqueue(wg->packet_crypt_wq); 235 wg_packet_queue_free(&wg->decrypt_queue, true); 236 wg_packet_queue_free(&wg->encrypt_queue, true); 237 rcu_barrier(); /* Wait for all the peers to be actually freed. */ 238 wg_ratelimiter_uninit(); 239 memzero_explicit(&wg->static_identity, sizeof(wg->static_identity)); 240 skb_queue_purge(&wg->incoming_handshakes); 241 free_percpu(dev->tstats); 242 free_percpu(wg->incoming_handshakes_worker); 243 if (wg->have_creating_net_ref) 244 put_net(wg->creating_net); 245 kvfree(wg->index_hashtable); 246 kvfree(wg->peer_hashtable); 247 mutex_unlock(&wg->device_update_lock); 248 249 pr_debug("%s: Interface deleted\n", dev->name); 250 free_netdev(dev); 251 } 252 253 static const struct device_type device_type = { .name = KBUILD_MODNAME }; 254 255 static void wg_setup(struct net_device *dev) 256 { 257 struct wg_device *wg = netdev_priv(dev); 258 enum { WG_NETDEV_FEATURES = NETIF_F_HW_CSUM | NETIF_F_RXCSUM | 259 NETIF_F_SG | NETIF_F_GSO | 260 NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA }; 261 const int overhead = MESSAGE_MINIMUM_LENGTH + sizeof(struct udphdr) + 262 max(sizeof(struct ipv6hdr), sizeof(struct iphdr)); 263 264 dev->netdev_ops = &netdev_ops; 265 dev->hard_header_len = 0; 266 dev->addr_len = 0; 267 dev->needed_headroom = DATA_PACKET_HEAD_ROOM; 268 dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE); 269 dev->type = ARPHRD_NONE; 270 dev->flags = IFF_POINTOPOINT | IFF_NOARP; 271 dev->priv_flags |= IFF_NO_QUEUE; 272 dev->features |= NETIF_F_LLTX; 273 dev->features |= WG_NETDEV_FEATURES; 274 dev->hw_features |= WG_NETDEV_FEATURES; 275 dev->hw_enc_features |= WG_NETDEV_FEATURES; 276 dev->mtu = ETH_DATA_LEN - overhead; 277 dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead; 278 279 SET_NETDEV_DEVTYPE(dev, &device_type); 280 281 /* We need to keep the dst around in case of icmp replies. */ 282 netif_keep_dst(dev); 283 284 memset(wg, 0, sizeof(*wg)); 285 wg->dev = dev; 286 } 287 288 static int wg_newlink(struct net *src_net, struct net_device *dev, 289 struct nlattr *tb[], struct nlattr *data[], 290 struct netlink_ext_ack *extack) 291 { 292 struct wg_device *wg = netdev_priv(dev); 293 int ret = -ENOMEM; 294 295 wg->creating_net = src_net; 296 init_rwsem(&wg->static_identity.lock); 297 mutex_init(&wg->socket_update_lock); 298 mutex_init(&wg->device_update_lock); 299 skb_queue_head_init(&wg->incoming_handshakes); 300 wg_allowedips_init(&wg->peer_allowedips); 301 wg_cookie_checker_init(&wg->cookie_checker, wg); 302 INIT_LIST_HEAD(&wg->peer_list); 303 wg->device_update_gen = 1; 304 305 wg->peer_hashtable = wg_pubkey_hashtable_alloc(); 306 if (!wg->peer_hashtable) 307 return ret; 308 309 wg->index_hashtable = wg_index_hashtable_alloc(); 310 if (!wg->index_hashtable) 311 goto err_free_peer_hashtable; 312 313 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); 314 if (!dev->tstats) 315 goto err_free_index_hashtable; 316 317 wg->incoming_handshakes_worker = 318 wg_packet_percpu_multicore_worker_alloc( 319 wg_packet_handshake_receive_worker, wg); 320 if (!wg->incoming_handshakes_worker) 321 goto err_free_tstats; 322 323 wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s", 324 WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name); 325 if (!wg->handshake_receive_wq) 326 goto err_free_incoming_handshakes; 327 328 wg->handshake_send_wq = alloc_workqueue("wg-kex-%s", 329 WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name); 330 if (!wg->handshake_send_wq) 331 goto err_destroy_handshake_receive; 332 333 wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s", 334 WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name); 335 if (!wg->packet_crypt_wq) 336 goto err_destroy_handshake_send; 337 338 ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker, 339 true, MAX_QUEUED_PACKETS); 340 if (ret < 0) 341 goto err_destroy_packet_crypt; 342 343 ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker, 344 true, MAX_QUEUED_PACKETS); 345 if (ret < 0) 346 goto err_free_encrypt_queue; 347 348 ret = wg_ratelimiter_init(); 349 if (ret < 0) 350 goto err_free_decrypt_queue; 351 352 ret = register_netdevice(dev); 353 if (ret < 0) 354 goto err_uninit_ratelimiter; 355 356 list_add(&wg->device_list, &device_list); 357 358 /* We wait until the end to assign priv_destructor, so that 359 * register_netdevice doesn't call it for us if it fails. 360 */ 361 dev->priv_destructor = wg_destruct; 362 363 pr_debug("%s: Interface created\n", dev->name); 364 return ret; 365 366 err_uninit_ratelimiter: 367 wg_ratelimiter_uninit(); 368 err_free_decrypt_queue: 369 wg_packet_queue_free(&wg->decrypt_queue, true); 370 err_free_encrypt_queue: 371 wg_packet_queue_free(&wg->encrypt_queue, true); 372 err_destroy_packet_crypt: 373 destroy_workqueue(wg->packet_crypt_wq); 374 err_destroy_handshake_send: 375 destroy_workqueue(wg->handshake_send_wq); 376 err_destroy_handshake_receive: 377 destroy_workqueue(wg->handshake_receive_wq); 378 err_free_incoming_handshakes: 379 free_percpu(wg->incoming_handshakes_worker); 380 err_free_tstats: 381 free_percpu(dev->tstats); 382 err_free_index_hashtable: 383 kvfree(wg->index_hashtable); 384 err_free_peer_hashtable: 385 kvfree(wg->peer_hashtable); 386 return ret; 387 } 388 389 static struct rtnl_link_ops link_ops __read_mostly = { 390 .kind = KBUILD_MODNAME, 391 .priv_size = sizeof(struct wg_device), 392 .setup = wg_setup, 393 .newlink = wg_newlink, 394 }; 395 396 static int wg_netdevice_notification(struct notifier_block *nb, 397 unsigned long action, void *data) 398 { 399 struct net_device *dev = ((struct netdev_notifier_info *)data)->dev; 400 struct wg_device *wg = netdev_priv(dev); 401 402 ASSERT_RTNL(); 403 404 if (action != NETDEV_REGISTER || dev->netdev_ops != &netdev_ops) 405 return 0; 406 407 if (dev_net(dev) == wg->creating_net && wg->have_creating_net_ref) { 408 put_net(wg->creating_net); 409 wg->have_creating_net_ref = false; 410 } else if (dev_net(dev) != wg->creating_net && 411 !wg->have_creating_net_ref) { 412 wg->have_creating_net_ref = true; 413 get_net(wg->creating_net); 414 } 415 return 0; 416 } 417 418 static struct notifier_block netdevice_notifier = { 419 .notifier_call = wg_netdevice_notification 420 }; 421 422 int __init wg_device_init(void) 423 { 424 int ret; 425 426 #ifdef CONFIG_PM_SLEEP 427 ret = register_pm_notifier(&pm_notifier); 428 if (ret) 429 return ret; 430 #endif 431 432 ret = register_netdevice_notifier(&netdevice_notifier); 433 if (ret) 434 goto error_pm; 435 436 ret = rtnl_link_register(&link_ops); 437 if (ret) 438 goto error_netdevice; 439 440 return 0; 441 442 error_netdevice: 443 unregister_netdevice_notifier(&netdevice_notifier); 444 error_pm: 445 #ifdef CONFIG_PM_SLEEP 446 unregister_pm_notifier(&pm_notifier); 447 #endif 448 return ret; 449 } 450 451 void wg_device_uninit(void) 452 { 453 rtnl_link_unregister(&link_ops); 454 unregister_netdevice_notifier(&netdevice_notifier); 455 #ifdef CONFIG_PM_SLEEP 456 unregister_pm_notifier(&pm_notifier); 457 #endif 458 rcu_barrier(); 459 } 460