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) || 73 IS_ENABLED(CONFIG_PM_USERSPACE_AUTOSLEEP)) 74 return 0; 75 76 if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE) 77 return 0; 78 79 rtnl_lock(); 80 list_for_each_entry(wg, &device_list, device_list) { 81 mutex_lock(&wg->device_update_lock); 82 list_for_each_entry(peer, &wg->peer_list, peer_list) { 83 del_timer(&peer->timer_zero_key_material); 84 wg_noise_handshake_clear(&peer->handshake); 85 wg_noise_keypairs_clear(&peer->keypairs); 86 } 87 mutex_unlock(&wg->device_update_lock); 88 } 89 rtnl_unlock(); 90 rcu_barrier(); 91 return 0; 92 } 93 94 static struct notifier_block pm_notifier = { .notifier_call = wg_pm_notification }; 95 96 static int wg_vm_notification(struct notifier_block *nb, unsigned long action, void *data) 97 { 98 struct wg_device *wg; 99 struct wg_peer *peer; 100 101 rtnl_lock(); 102 list_for_each_entry(wg, &device_list, device_list) { 103 mutex_lock(&wg->device_update_lock); 104 list_for_each_entry(peer, &wg->peer_list, peer_list) 105 wg_noise_expire_current_peer_keypairs(peer); 106 mutex_unlock(&wg->device_update_lock); 107 } 108 rtnl_unlock(); 109 return 0; 110 } 111 112 static struct notifier_block vm_notifier = { .notifier_call = wg_vm_notification }; 113 114 static int wg_stop(struct net_device *dev) 115 { 116 struct wg_device *wg = netdev_priv(dev); 117 struct wg_peer *peer; 118 struct sk_buff *skb; 119 120 mutex_lock(&wg->device_update_lock); 121 list_for_each_entry(peer, &wg->peer_list, peer_list) { 122 wg_packet_purge_staged_packets(peer); 123 wg_timers_stop(peer); 124 wg_noise_handshake_clear(&peer->handshake); 125 wg_noise_keypairs_clear(&peer->keypairs); 126 wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake); 127 } 128 mutex_unlock(&wg->device_update_lock); 129 while ((skb = ptr_ring_consume(&wg->handshake_queue.ring)) != NULL) 130 kfree_skb(skb); 131 atomic_set(&wg->handshake_queue_len, 0); 132 wg_socket_reinit(wg, NULL, NULL); 133 return 0; 134 } 135 136 static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev) 137 { 138 struct wg_device *wg = netdev_priv(dev); 139 struct sk_buff_head packets; 140 struct wg_peer *peer; 141 struct sk_buff *next; 142 sa_family_t family; 143 u32 mtu; 144 int ret; 145 146 if (unlikely(!wg_check_packet_protocol(skb))) { 147 ret = -EPROTONOSUPPORT; 148 net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name); 149 goto err; 150 } 151 152 peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb); 153 if (unlikely(!peer)) { 154 ret = -ENOKEY; 155 if (skb->protocol == htons(ETH_P_IP)) 156 net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n", 157 dev->name, &ip_hdr(skb)->daddr); 158 else if (skb->protocol == htons(ETH_P_IPV6)) 159 net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n", 160 dev->name, &ipv6_hdr(skb)->daddr); 161 goto err_icmp; 162 } 163 164 family = READ_ONCE(peer->endpoint.addr.sa_family); 165 if (unlikely(family != AF_INET && family != AF_INET6)) { 166 ret = -EDESTADDRREQ; 167 net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n", 168 dev->name, peer->internal_id); 169 goto err_peer; 170 } 171 172 mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; 173 174 __skb_queue_head_init(&packets); 175 if (!skb_is_gso(skb)) { 176 skb_mark_not_on_list(skb); 177 } else { 178 struct sk_buff *segs = skb_gso_segment(skb, 0); 179 180 if (IS_ERR(segs)) { 181 ret = PTR_ERR(segs); 182 goto err_peer; 183 } 184 dev_kfree_skb(skb); 185 skb = segs; 186 } 187 188 skb_list_walk_safe(skb, skb, next) { 189 skb_mark_not_on_list(skb); 190 191 skb = skb_share_check(skb, GFP_ATOMIC); 192 if (unlikely(!skb)) 193 continue; 194 195 /* We only need to keep the original dst around for icmp, 196 * so at this point we're in a position to drop it. 197 */ 198 skb_dst_drop(skb); 199 200 PACKET_CB(skb)->mtu = mtu; 201 202 __skb_queue_tail(&packets, skb); 203 } 204 205 spin_lock_bh(&peer->staged_packet_queue.lock); 206 /* If the queue is getting too big, we start removing the oldest packets 207 * until it's small again. We do this before adding the new packet, so 208 * we don't remove GSO segments that are in excess. 209 */ 210 while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) { 211 dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue)); 212 ++dev->stats.tx_dropped; 213 } 214 skb_queue_splice_tail(&packets, &peer->staged_packet_queue); 215 spin_unlock_bh(&peer->staged_packet_queue.lock); 216 217 wg_packet_send_staged_packets(peer); 218 219 wg_peer_put(peer); 220 return NETDEV_TX_OK; 221 222 err_peer: 223 wg_peer_put(peer); 224 err_icmp: 225 if (skb->protocol == htons(ETH_P_IP)) 226 icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 227 else if (skb->protocol == htons(ETH_P_IPV6)) 228 icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0); 229 err: 230 ++dev->stats.tx_errors; 231 kfree_skb(skb); 232 return ret; 233 } 234 235 static const struct net_device_ops netdev_ops = { 236 .ndo_open = wg_open, 237 .ndo_stop = wg_stop, 238 .ndo_start_xmit = wg_xmit, 239 .ndo_get_stats64 = dev_get_tstats64 240 }; 241 242 static void wg_destruct(struct net_device *dev) 243 { 244 struct wg_device *wg = netdev_priv(dev); 245 246 rtnl_lock(); 247 list_del(&wg->device_list); 248 rtnl_unlock(); 249 mutex_lock(&wg->device_update_lock); 250 rcu_assign_pointer(wg->creating_net, NULL); 251 wg->incoming_port = 0; 252 wg_socket_reinit(wg, NULL, NULL); 253 /* The final references are cleared in the below calls to destroy_workqueue. */ 254 wg_peer_remove_all(wg); 255 destroy_workqueue(wg->handshake_receive_wq); 256 destroy_workqueue(wg->handshake_send_wq); 257 destroy_workqueue(wg->packet_crypt_wq); 258 wg_packet_queue_free(&wg->handshake_queue, true); 259 wg_packet_queue_free(&wg->decrypt_queue, false); 260 wg_packet_queue_free(&wg->encrypt_queue, false); 261 rcu_barrier(); /* Wait for all the peers to be actually freed. */ 262 wg_ratelimiter_uninit(); 263 memzero_explicit(&wg->static_identity, sizeof(wg->static_identity)); 264 free_percpu(dev->tstats); 265 kvfree(wg->index_hashtable); 266 kvfree(wg->peer_hashtable); 267 mutex_unlock(&wg->device_update_lock); 268 269 pr_debug("%s: Interface destroyed\n", dev->name); 270 free_netdev(dev); 271 } 272 273 static const struct device_type device_type = { .name = KBUILD_MODNAME }; 274 275 static void wg_setup(struct net_device *dev) 276 { 277 struct wg_device *wg = netdev_priv(dev); 278 enum { WG_NETDEV_FEATURES = NETIF_F_HW_CSUM | NETIF_F_RXCSUM | 279 NETIF_F_SG | NETIF_F_GSO | 280 NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA }; 281 const int overhead = MESSAGE_MINIMUM_LENGTH + sizeof(struct udphdr) + 282 max(sizeof(struct ipv6hdr), sizeof(struct iphdr)); 283 284 dev->netdev_ops = &netdev_ops; 285 dev->header_ops = &ip_tunnel_header_ops; 286 dev->hard_header_len = 0; 287 dev->addr_len = 0; 288 dev->needed_headroom = DATA_PACKET_HEAD_ROOM; 289 dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE); 290 dev->type = ARPHRD_NONE; 291 dev->flags = IFF_POINTOPOINT | IFF_NOARP; 292 dev->priv_flags |= IFF_NO_QUEUE; 293 dev->features |= NETIF_F_LLTX; 294 dev->features |= WG_NETDEV_FEATURES; 295 dev->hw_features |= WG_NETDEV_FEATURES; 296 dev->hw_enc_features |= WG_NETDEV_FEATURES; 297 dev->mtu = ETH_DATA_LEN - overhead; 298 dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead; 299 300 SET_NETDEV_DEVTYPE(dev, &device_type); 301 302 /* We need to keep the dst around in case of icmp replies. */ 303 netif_keep_dst(dev); 304 305 memset(wg, 0, sizeof(*wg)); 306 wg->dev = dev; 307 } 308 309 static int wg_newlink(struct net *src_net, struct net_device *dev, 310 struct nlattr *tb[], struct nlattr *data[], 311 struct netlink_ext_ack *extack) 312 { 313 struct wg_device *wg = netdev_priv(dev); 314 int ret = -ENOMEM; 315 316 rcu_assign_pointer(wg->creating_net, src_net); 317 init_rwsem(&wg->static_identity.lock); 318 mutex_init(&wg->socket_update_lock); 319 mutex_init(&wg->device_update_lock); 320 wg_allowedips_init(&wg->peer_allowedips); 321 wg_cookie_checker_init(&wg->cookie_checker, wg); 322 INIT_LIST_HEAD(&wg->peer_list); 323 wg->device_update_gen = 1; 324 325 wg->peer_hashtable = wg_pubkey_hashtable_alloc(); 326 if (!wg->peer_hashtable) 327 return ret; 328 329 wg->index_hashtable = wg_index_hashtable_alloc(); 330 if (!wg->index_hashtable) 331 goto err_free_peer_hashtable; 332 333 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); 334 if (!dev->tstats) 335 goto err_free_index_hashtable; 336 337 wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s", 338 WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name); 339 if (!wg->handshake_receive_wq) 340 goto err_free_tstats; 341 342 wg->handshake_send_wq = alloc_workqueue("wg-kex-%s", 343 WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name); 344 if (!wg->handshake_send_wq) 345 goto err_destroy_handshake_receive; 346 347 wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s", 348 WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name); 349 if (!wg->packet_crypt_wq) 350 goto err_destroy_handshake_send; 351 352 ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker, 353 MAX_QUEUED_PACKETS); 354 if (ret < 0) 355 goto err_destroy_packet_crypt; 356 357 ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker, 358 MAX_QUEUED_PACKETS); 359 if (ret < 0) 360 goto err_free_encrypt_queue; 361 362 ret = wg_packet_queue_init(&wg->handshake_queue, wg_packet_handshake_receive_worker, 363 MAX_QUEUED_INCOMING_HANDSHAKES); 364 if (ret < 0) 365 goto err_free_decrypt_queue; 366 367 ret = wg_ratelimiter_init(); 368 if (ret < 0) 369 goto err_free_handshake_queue; 370 371 ret = register_netdevice(dev); 372 if (ret < 0) 373 goto err_uninit_ratelimiter; 374 375 list_add(&wg->device_list, &device_list); 376 377 /* We wait until the end to assign priv_destructor, so that 378 * register_netdevice doesn't call it for us if it fails. 379 */ 380 dev->priv_destructor = wg_destruct; 381 382 pr_debug("%s: Interface created\n", dev->name); 383 return ret; 384 385 err_uninit_ratelimiter: 386 wg_ratelimiter_uninit(); 387 err_free_handshake_queue: 388 wg_packet_queue_free(&wg->handshake_queue, false); 389 err_free_decrypt_queue: 390 wg_packet_queue_free(&wg->decrypt_queue, false); 391 err_free_encrypt_queue: 392 wg_packet_queue_free(&wg->encrypt_queue, false); 393 err_destroy_packet_crypt: 394 destroy_workqueue(wg->packet_crypt_wq); 395 err_destroy_handshake_send: 396 destroy_workqueue(wg->handshake_send_wq); 397 err_destroy_handshake_receive: 398 destroy_workqueue(wg->handshake_receive_wq); 399 err_free_tstats: 400 free_percpu(dev->tstats); 401 err_free_index_hashtable: 402 kvfree(wg->index_hashtable); 403 err_free_peer_hashtable: 404 kvfree(wg->peer_hashtable); 405 return ret; 406 } 407 408 static struct rtnl_link_ops link_ops __read_mostly = { 409 .kind = KBUILD_MODNAME, 410 .priv_size = sizeof(struct wg_device), 411 .setup = wg_setup, 412 .newlink = wg_newlink, 413 }; 414 415 static void wg_netns_pre_exit(struct net *net) 416 { 417 struct wg_device *wg; 418 struct wg_peer *peer; 419 420 rtnl_lock(); 421 list_for_each_entry(wg, &device_list, device_list) { 422 if (rcu_access_pointer(wg->creating_net) == net) { 423 pr_debug("%s: Creating namespace exiting\n", wg->dev->name); 424 netif_carrier_off(wg->dev); 425 mutex_lock(&wg->device_update_lock); 426 rcu_assign_pointer(wg->creating_net, NULL); 427 wg_socket_reinit(wg, NULL, NULL); 428 list_for_each_entry(peer, &wg->peer_list, peer_list) 429 wg_socket_clear_peer_endpoint_src(peer); 430 mutex_unlock(&wg->device_update_lock); 431 } 432 } 433 rtnl_unlock(); 434 } 435 436 static struct pernet_operations pernet_ops = { 437 .pre_exit = wg_netns_pre_exit 438 }; 439 440 int __init wg_device_init(void) 441 { 442 int ret; 443 444 ret = register_pm_notifier(&pm_notifier); 445 if (ret) 446 return ret; 447 448 ret = register_random_vmfork_notifier(&vm_notifier); 449 if (ret) 450 goto error_pm; 451 452 ret = register_pernet_device(&pernet_ops); 453 if (ret) 454 goto error_vm; 455 456 ret = rtnl_link_register(&link_ops); 457 if (ret) 458 goto error_pernet; 459 460 return 0; 461 462 error_pernet: 463 unregister_pernet_device(&pernet_ops); 464 error_vm: 465 unregister_random_vmfork_notifier(&vm_notifier); 466 error_pm: 467 unregister_pm_notifier(&pm_notifier); 468 return ret; 469 } 470 471 void wg_device_uninit(void) 472 { 473 rtnl_link_unregister(&link_ops); 474 unregister_pernet_device(&pernet_ops); 475 unregister_random_vmfork_notifier(&vm_notifier); 476 unregister_pm_notifier(&pm_notifier); 477 rcu_barrier(); 478 } 479