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/dst_metadata.h> 23 #include <net/icmp.h> 24 #include <net/rtnetlink.h> 25 #include <net/ip_tunnels.h> 26 #include <net/addrconf.h> 27 28 static LIST_HEAD(device_list); 29 30 static int wg_open(struct net_device *dev) 31 { 32 struct in_device *dev_v4 = __in_dev_get_rtnl(dev); 33 struct inet6_dev *dev_v6 = __in6_dev_get(dev); 34 struct wg_device *wg = netdev_priv(dev); 35 struct wg_peer *peer; 36 int ret; 37 38 if (dev_v4) { 39 /* At some point we might put this check near the ip_rt_send_ 40 * redirect call of ip_forward in net/ipv4/ip_forward.c, similar 41 * to the current secpath check. 42 */ 43 IN_DEV_CONF_SET(dev_v4, SEND_REDIRECTS, false); 44 IPV4_DEVCONF_ALL(dev_net(dev), SEND_REDIRECTS) = false; 45 } 46 if (dev_v6) 47 dev_v6->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_NONE; 48 49 mutex_lock(&wg->device_update_lock); 50 ret = wg_socket_init(wg, wg->incoming_port); 51 if (ret < 0) 52 goto out; 53 list_for_each_entry(peer, &wg->peer_list, peer_list) { 54 wg_packet_send_staged_packets(peer); 55 if (peer->persistent_keepalive_interval) 56 wg_packet_send_keepalive(peer); 57 } 58 out: 59 mutex_unlock(&wg->device_update_lock); 60 return ret; 61 } 62 63 static int wg_pm_notification(struct notifier_block *nb, unsigned long action, 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 95 static int wg_vm_notification(struct notifier_block *nb, unsigned long action, void *data) 96 { 97 struct wg_device *wg; 98 struct wg_peer *peer; 99 100 rtnl_lock(); 101 list_for_each_entry(wg, &device_list, device_list) { 102 mutex_lock(&wg->device_update_lock); 103 list_for_each_entry(peer, &wg->peer_list, peer_list) 104 wg_noise_expire_current_peer_keypairs(peer); 105 mutex_unlock(&wg->device_update_lock); 106 } 107 rtnl_unlock(); 108 return 0; 109 } 110 111 static struct notifier_block vm_notifier = { .notifier_call = wg_vm_notification }; 112 113 static int wg_stop(struct net_device *dev) 114 { 115 struct wg_device *wg = netdev_priv(dev); 116 struct wg_peer *peer; 117 struct sk_buff *skb; 118 119 mutex_lock(&wg->device_update_lock); 120 list_for_each_entry(peer, &wg->peer_list, peer_list) { 121 wg_packet_purge_staged_packets(peer); 122 wg_timers_stop(peer); 123 wg_noise_handshake_clear(&peer->handshake); 124 wg_noise_keypairs_clear(&peer->keypairs); 125 wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake); 126 } 127 mutex_unlock(&wg->device_update_lock); 128 while ((skb = ptr_ring_consume(&wg->handshake_queue.ring)) != NULL) 129 kfree_skb(skb); 130 atomic_set(&wg->handshake_queue_len, 0); 131 wg_socket_reinit(wg, NULL, NULL); 132 return 0; 133 } 134 135 static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev) 136 { 137 struct wg_device *wg = netdev_priv(dev); 138 struct sk_buff_head packets; 139 struct wg_peer *peer; 140 struct sk_buff *next; 141 sa_family_t family; 142 u32 mtu; 143 int ret; 144 145 if (unlikely(!wg_check_packet_protocol(skb))) { 146 ret = -EPROTONOSUPPORT; 147 net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name); 148 goto err; 149 } 150 151 peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb); 152 if (unlikely(!peer)) { 153 ret = -ENOKEY; 154 if (skb->protocol == htons(ETH_P_IP)) 155 net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n", 156 dev->name, &ip_hdr(skb)->daddr); 157 else if (skb->protocol == htons(ETH_P_IPV6)) 158 net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n", 159 dev->name, &ipv6_hdr(skb)->daddr); 160 goto err_icmp; 161 } 162 163 family = READ_ONCE(peer->endpoint.addr.sa_family); 164 if (unlikely(family != AF_INET && family != AF_INET6)) { 165 ret = -EDESTADDRREQ; 166 net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n", 167 dev->name, peer->internal_id); 168 goto err_peer; 169 } 170 171 mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; 172 173 __skb_queue_head_init(&packets); 174 if (!skb_is_gso(skb)) { 175 skb_mark_not_on_list(skb); 176 } else { 177 struct sk_buff *segs = skb_gso_segment(skb, 0); 178 179 if (IS_ERR(segs)) { 180 ret = PTR_ERR(segs); 181 goto err_peer; 182 } 183 dev_kfree_skb(skb); 184 skb = segs; 185 } 186 187 skb_list_walk_safe(skb, skb, next) { 188 skb_mark_not_on_list(skb); 189 190 skb = skb_share_check(skb, GFP_ATOMIC); 191 if (unlikely(!skb)) 192 continue; 193 194 /* We only need to keep the original dst around for icmp, 195 * so at this point we're in a position to drop it. 196 */ 197 skb_dst_drop(skb); 198 199 PACKET_CB(skb)->mtu = mtu; 200 201 __skb_queue_tail(&packets, skb); 202 } 203 204 spin_lock_bh(&peer->staged_packet_queue.lock); 205 /* If the queue is getting too big, we start removing the oldest packets 206 * until it's small again. We do this before adding the new packet, so 207 * we don't remove GSO segments that are in excess. 208 */ 209 while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) { 210 dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue)); 211 ++dev->stats.tx_dropped; 212 } 213 skb_queue_splice_tail(&packets, &peer->staged_packet_queue); 214 spin_unlock_bh(&peer->staged_packet_queue.lock); 215 216 wg_packet_send_staged_packets(peer); 217 218 wg_peer_put(peer); 219 return NETDEV_TX_OK; 220 221 err_peer: 222 wg_peer_put(peer); 223 err_icmp: 224 if (skb->protocol == htons(ETH_P_IP)) 225 icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 226 else if (skb->protocol == htons(ETH_P_IPV6)) 227 icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0); 228 err: 229 ++dev->stats.tx_errors; 230 kfree_skb(skb); 231 return ret; 232 } 233 234 static const struct net_device_ops netdev_ops = { 235 .ndo_open = wg_open, 236 .ndo_stop = wg_stop, 237 .ndo_start_xmit = wg_xmit, 238 .ndo_get_stats64 = dev_get_tstats64 239 }; 240 241 static void wg_destruct(struct net_device *dev) 242 { 243 struct wg_device *wg = netdev_priv(dev); 244 245 rtnl_lock(); 246 list_del(&wg->device_list); 247 rtnl_unlock(); 248 mutex_lock(&wg->device_update_lock); 249 rcu_assign_pointer(wg->creating_net, NULL); 250 wg->incoming_port = 0; 251 wg_socket_reinit(wg, NULL, NULL); 252 /* The final references are cleared in the below calls to destroy_workqueue. */ 253 wg_peer_remove_all(wg); 254 destroy_workqueue(wg->handshake_receive_wq); 255 destroy_workqueue(wg->handshake_send_wq); 256 destroy_workqueue(wg->packet_crypt_wq); 257 wg_packet_queue_free(&wg->handshake_queue, true); 258 wg_packet_queue_free(&wg->decrypt_queue, false); 259 wg_packet_queue_free(&wg->encrypt_queue, false); 260 rcu_barrier(); /* Wait for all the peers to be actually freed. */ 261 wg_ratelimiter_uninit(); 262 memzero_explicit(&wg->static_identity, sizeof(wg->static_identity)); 263 free_percpu(dev->tstats); 264 kvfree(wg->index_hashtable); 265 kvfree(wg->peer_hashtable); 266 mutex_unlock(&wg->device_update_lock); 267 268 pr_debug("%s: Interface destroyed\n", dev->name); 269 free_netdev(dev); 270 } 271 272 static const struct device_type device_type = { .name = KBUILD_MODNAME }; 273 274 static void wg_setup(struct net_device *dev) 275 { 276 struct wg_device *wg = netdev_priv(dev); 277 enum { WG_NETDEV_FEATURES = NETIF_F_HW_CSUM | NETIF_F_RXCSUM | 278 NETIF_F_SG | NETIF_F_GSO | 279 NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA }; 280 const int overhead = MESSAGE_MINIMUM_LENGTH + sizeof(struct udphdr) + 281 max(sizeof(struct ipv6hdr), sizeof(struct iphdr)); 282 283 dev->netdev_ops = &netdev_ops; 284 dev->header_ops = &ip_tunnel_header_ops; 285 dev->hard_header_len = 0; 286 dev->addr_len = 0; 287 dev->needed_headroom = DATA_PACKET_HEAD_ROOM; 288 dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE); 289 dev->type = ARPHRD_NONE; 290 dev->flags = IFF_POINTOPOINT | IFF_NOARP; 291 dev->priv_flags |= IFF_NO_QUEUE; 292 dev->features |= NETIF_F_LLTX; 293 dev->features |= WG_NETDEV_FEATURES; 294 dev->hw_features |= WG_NETDEV_FEATURES; 295 dev->hw_enc_features |= WG_NETDEV_FEATURES; 296 dev->mtu = ETH_DATA_LEN - overhead; 297 dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead; 298 299 SET_NETDEV_DEVTYPE(dev, &device_type); 300 301 /* We need to keep the dst around in case of icmp replies. */ 302 netif_keep_dst(dev); 303 304 memset(wg, 0, sizeof(*wg)); 305 wg->dev = dev; 306 } 307 308 static int wg_newlink(struct net *src_net, struct net_device *dev, 309 struct nlattr *tb[], struct nlattr *data[], 310 struct netlink_ext_ack *extack) 311 { 312 struct wg_device *wg = netdev_priv(dev); 313 int ret = -ENOMEM; 314 315 rcu_assign_pointer(wg->creating_net, src_net); 316 init_rwsem(&wg->static_identity.lock); 317 mutex_init(&wg->socket_update_lock); 318 mutex_init(&wg->device_update_lock); 319 wg_allowedips_init(&wg->peer_allowedips); 320 wg_cookie_checker_init(&wg->cookie_checker, wg); 321 INIT_LIST_HEAD(&wg->peer_list); 322 wg->device_update_gen = 1; 323 324 wg->peer_hashtable = wg_pubkey_hashtable_alloc(); 325 if (!wg->peer_hashtable) 326 return ret; 327 328 wg->index_hashtable = wg_index_hashtable_alloc(); 329 if (!wg->index_hashtable) 330 goto err_free_peer_hashtable; 331 332 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); 333 if (!dev->tstats) 334 goto err_free_index_hashtable; 335 336 wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s", 337 WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name); 338 if (!wg->handshake_receive_wq) 339 goto err_free_tstats; 340 341 wg->handshake_send_wq = alloc_workqueue("wg-kex-%s", 342 WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name); 343 if (!wg->handshake_send_wq) 344 goto err_destroy_handshake_receive; 345 346 wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s", 347 WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name); 348 if (!wg->packet_crypt_wq) 349 goto err_destroy_handshake_send; 350 351 ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker, 352 MAX_QUEUED_PACKETS); 353 if (ret < 0) 354 goto err_destroy_packet_crypt; 355 356 ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker, 357 MAX_QUEUED_PACKETS); 358 if (ret < 0) 359 goto err_free_encrypt_queue; 360 361 ret = wg_packet_queue_init(&wg->handshake_queue, wg_packet_handshake_receive_worker, 362 MAX_QUEUED_INCOMING_HANDSHAKES); 363 if (ret < 0) 364 goto err_free_decrypt_queue; 365 366 ret = wg_ratelimiter_init(); 367 if (ret < 0) 368 goto err_free_handshake_queue; 369 370 ret = register_netdevice(dev); 371 if (ret < 0) 372 goto err_uninit_ratelimiter; 373 374 list_add(&wg->device_list, &device_list); 375 376 /* We wait until the end to assign priv_destructor, so that 377 * register_netdevice doesn't call it for us if it fails. 378 */ 379 dev->priv_destructor = wg_destruct; 380 381 pr_debug("%s: Interface created\n", dev->name); 382 return ret; 383 384 err_uninit_ratelimiter: 385 wg_ratelimiter_uninit(); 386 err_free_handshake_queue: 387 wg_packet_queue_free(&wg->handshake_queue, false); 388 err_free_decrypt_queue: 389 wg_packet_queue_free(&wg->decrypt_queue, false); 390 err_free_encrypt_queue: 391 wg_packet_queue_free(&wg->encrypt_queue, false); 392 err_destroy_packet_crypt: 393 destroy_workqueue(wg->packet_crypt_wq); 394 err_destroy_handshake_send: 395 destroy_workqueue(wg->handshake_send_wq); 396 err_destroy_handshake_receive: 397 destroy_workqueue(wg->handshake_receive_wq); 398 err_free_tstats: 399 free_percpu(dev->tstats); 400 err_free_index_hashtable: 401 kvfree(wg->index_hashtable); 402 err_free_peer_hashtable: 403 kvfree(wg->peer_hashtable); 404 return ret; 405 } 406 407 static struct rtnl_link_ops link_ops __read_mostly = { 408 .kind = KBUILD_MODNAME, 409 .priv_size = sizeof(struct wg_device), 410 .setup = wg_setup, 411 .newlink = wg_newlink, 412 }; 413 414 static void wg_netns_pre_exit(struct net *net) 415 { 416 struct wg_device *wg; 417 struct wg_peer *peer; 418 419 rtnl_lock(); 420 list_for_each_entry(wg, &device_list, device_list) { 421 if (rcu_access_pointer(wg->creating_net) == net) { 422 pr_debug("%s: Creating namespace exiting\n", wg->dev->name); 423 netif_carrier_off(wg->dev); 424 mutex_lock(&wg->device_update_lock); 425 rcu_assign_pointer(wg->creating_net, NULL); 426 wg_socket_reinit(wg, NULL, NULL); 427 list_for_each_entry(peer, &wg->peer_list, peer_list) 428 wg_socket_clear_peer_endpoint_src(peer); 429 mutex_unlock(&wg->device_update_lock); 430 } 431 } 432 rtnl_unlock(); 433 } 434 435 static struct pernet_operations pernet_ops = { 436 .pre_exit = wg_netns_pre_exit 437 }; 438 439 int __init wg_device_init(void) 440 { 441 int ret; 442 443 ret = register_pm_notifier(&pm_notifier); 444 if (ret) 445 return ret; 446 447 ret = register_random_vmfork_notifier(&vm_notifier); 448 if (ret) 449 goto error_pm; 450 451 ret = register_pernet_device(&pernet_ops); 452 if (ret) 453 goto error_vm; 454 455 ret = rtnl_link_register(&link_ops); 456 if (ret) 457 goto error_pernet; 458 459 return 0; 460 461 error_pernet: 462 unregister_pernet_device(&pernet_ops); 463 error_vm: 464 unregister_random_vmfork_notifier(&vm_notifier); 465 error_pm: 466 unregister_pm_notifier(&pm_notifier); 467 return ret; 468 } 469 470 void wg_device_uninit(void) 471 { 472 rtnl_link_unregister(&link_ops); 473 unregister_pernet_device(&pernet_ops); 474 unregister_random_vmfork_notifier(&vm_notifier); 475 unregister_pm_notifier(&pm_notifier); 476 rcu_barrier(); 477 } 478