drivers/net/wireguard/device.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2015-2019 Jason A. Donenfeld <[email protected]>. 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         mutex_lock(&wg->device_update_lock);
  49         ret = wg_socket_init(wg, wg->incoming_port);
  50         if (ret < 0)
  51                 goto out;
  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 out:
  58         mutex_unlock(&wg->device_update_lock);
  59         return ret;
  60 }
  61
  62 #ifdef CONFIG_PM_SLEEP
  63 static int wg_pm_notification(struct notifier_block *nb, unsigned long action,
  64                               void *data)
  65 {
  66         struct wg_device *wg;
  67         struct wg_peer *peer;
  68
  69         /* If the machine is constantly suspending and resuming, as part of
  70          * its normal operation rather than as a somewhat rare event, then we
  71          * don't actually want to clear keys.
  72          */
  73         if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || IS_ENABLED(CONFIG_ANDROID))
  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 #endif
  96
  97 static int wg_stop(struct net_device *dev)
  98 {
  99         struct wg_device *wg = netdev_priv(dev);
 100         struct wg_peer *peer;
 101
 102         mutex_lock(&wg->device_update_lock);
 103         list_for_each_entry(peer, &wg->peer_list, peer_list) {
 104                 wg_packet_purge_staged_packets(peer);
 105                 wg_timers_stop(peer);
 106                 wg_noise_handshake_clear(&peer->handshake);
 107                 wg_noise_keypairs_clear(&peer->keypairs);
 108                 wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake);
 109         }
 110         mutex_unlock(&wg->device_update_lock);
 111         skb_queue_purge(&wg->incoming_handshakes);
 112         wg_socket_reinit(wg, NULL, NULL);
 113         return 0;
 114 }
 115
 116 static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 117 {
 118         struct wg_device *wg = netdev_priv(dev);
 119         struct sk_buff_head packets;
 120         struct wg_peer *peer;
 121         struct sk_buff *next;
 122         sa_family_t family;
 123         u32 mtu;
 124         int ret;
 125
 126         if (unlikely(!wg_check_packet_protocol(skb))) {
 127                 ret = -EPROTONOSUPPORT;
 128                 net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name);
 129                 goto err;
 130         }
 131
 132         peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb);
 133         if (unlikely(!peer)) {
 134                 ret = -ENOKEY;
 135                 if (skb->protocol == htons(ETH_P_IP))
 136                         net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n",
 137                                             dev->name, &ip_hdr(skb)->daddr);
 138                 else if (skb->protocol == htons(ETH_P_IPV6))
 139                         net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n",
 140                                             dev->name, &ipv6_hdr(skb)->daddr);
 141                 goto err;
 142         }
 143
 144         family = READ_ONCE(peer->endpoint.addr.sa_family);
 145         if (unlikely(family != AF_INET && family != AF_INET6)) {
 146                 ret = -EDESTADDRREQ;
 147                 net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n",
 148                                     dev->name, peer->internal_id);
 149                 goto err_peer;
 150         }
 151
 152         mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 153
 154         __skb_queue_head_init(&packets);
 155         if (!skb_is_gso(skb)) {
 156                 skb_mark_not_on_list(skb);
 157         } else {
 158                 struct sk_buff *segs = skb_gso_segment(skb, 0);
 159
 160                 if (unlikely(IS_ERR(segs))) {
 161                         ret = PTR_ERR(segs);
 162                         goto err_peer;
 163                 }
 164                 dev_kfree_skb(skb);
 165                 skb = segs;
 166         }
 167
 168         skb_list_walk_safe(skb, skb, next) {
 169                 skb_mark_not_on_list(skb);
 170
 171                 skb = skb_share_check(skb, GFP_ATOMIC);
 172                 if (unlikely(!skb))
 173                         continue;
 174
 175                 /* We only need to keep the original dst around for icmp,
 176                  * so at this point we're in a position to drop it.
 177                  */
 178                 skb_dst_drop(skb);
 179
 180                 PACKET_CB(skb)->mtu = mtu;
 181
 182                 __skb_queue_tail(&packets, skb);
 183         }
 184
 185         spin_lock_bh(&peer->staged_packet_queue.lock);
 186         /* If the queue is getting too big, we start removing the oldest packets
 187          * until it's small again. We do this before adding the new packet, so
 188          * we don't remove GSO segments that are in excess.
 189          */
 190         while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) {
 191                 dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue));
 192                 ++dev->stats.tx_dropped;
 193         }
 194         skb_queue_splice_tail(&packets, &peer->staged_packet_queue);
 195         spin_unlock_bh(&peer->staged_packet_queue.lock);
 196
 197         wg_packet_send_staged_packets(peer);
 198
 199         wg_peer_put(peer);
 200         return NETDEV_TX_OK;
 201
 202 err_peer:
 203         wg_peer_put(peer);
 204 err:
 205         ++dev->stats.tx_errors;
 206         if (skb->protocol == htons(ETH_P_IP))
 207                 icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
 208         else if (skb->protocol == htons(ETH_P_IPV6))
 209                 icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
 210         kfree_skb(skb);
 211         return ret;
 212 }
 213
 214 static const struct net_device_ops netdev_ops = {
 215         .ndo_open               = wg_open,
 216         .ndo_stop               = wg_stop,
 217         .ndo_start_xmit         = wg_xmit,
 218         .ndo_get_stats64        = dev_get_tstats64
 219 };
 220
 221 static void wg_destruct(struct net_device *dev)
 222 {
 223         struct wg_device *wg = netdev_priv(dev);
 224
 225         rtnl_lock();
 226         list_del(&wg->device_list);
 227         rtnl_unlock();
 228         mutex_lock(&wg->device_update_lock);
 229         rcu_assign_pointer(wg->creating_net, NULL);
 230         wg->incoming_port = 0;
 231         wg_socket_reinit(wg, NULL, NULL);
 232         /* The final references are cleared in the below calls to destroy_workqueue. */
 233         wg_peer_remove_all(wg);
 234         destroy_workqueue(wg->handshake_receive_wq);
 235         destroy_workqueue(wg->handshake_send_wq);
 236         destroy_workqueue(wg->packet_crypt_wq);
 237         wg_packet_queue_free(&wg->decrypt_queue, true);
 238         wg_packet_queue_free(&wg->encrypt_queue, true);
 239         rcu_barrier(); /* Wait for all the peers to be actually freed. */
 240         wg_ratelimiter_uninit();
 241         memzero_explicit(&wg->static_identity, sizeof(wg->static_identity));
 242         skb_queue_purge(&wg->incoming_handshakes);
 243         free_percpu(dev->tstats);
 244         free_percpu(wg->incoming_handshakes_worker);
 245         kvfree(wg->index_hashtable);
 246         kvfree(wg->peer_hashtable);
 247         mutex_unlock(&wg->device_update_lock);
 248
 249         pr_debug("%s: Interface destroyed\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->header_ops = &ip_tunnel_header_ops;
 266         dev->hard_header_len = 0;
 267         dev->addr_len = 0;
 268         dev->needed_headroom = DATA_PACKET_HEAD_ROOM;
 269         dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE);
 270         dev->type = ARPHRD_NONE;
 271         dev->flags = IFF_POINTOPOINT | IFF_NOARP;
 272         dev->priv_flags |= IFF_NO_QUEUE;
 273         dev->features |= NETIF_F_LLTX;
 274         dev->features |= WG_NETDEV_FEATURES;
 275         dev->hw_features |= WG_NETDEV_FEATURES;
 276         dev->hw_enc_features |= WG_NETDEV_FEATURES;
 277         dev->mtu = ETH_DATA_LEN - overhead;
 278         dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead;
 279
 280         SET_NETDEV_DEVTYPE(dev, &device_type);
 281
 282         /* We need to keep the dst around in case of icmp replies. */
 283         netif_keep_dst(dev);
 284
 285         memset(wg, 0, sizeof(*wg));
 286         wg->dev = dev;
 287 }
 288
 289 static int wg_newlink(struct net *src_net, struct net_device *dev,
 290                       struct nlattr *tb[], struct nlattr *data[],
 291                       struct netlink_ext_ack *extack)
 292 {
 293         struct wg_device *wg = netdev_priv(dev);
 294         int ret = -ENOMEM;
 295
 296         rcu_assign_pointer(wg->creating_net, src_net);
 297         init_rwsem(&wg->static_identity.lock);
 298         mutex_init(&wg->socket_update_lock);
 299         mutex_init(&wg->device_update_lock);
 300         skb_queue_head_init(&wg->incoming_handshakes);
 301         wg_allowedips_init(&wg->peer_allowedips);
 302         wg_cookie_checker_init(&wg->cookie_checker, wg);
 303         INIT_LIST_HEAD(&wg->peer_list);
 304         wg->device_update_gen = 1;
 305
 306         wg->peer_hashtable = wg_pubkey_hashtable_alloc();
 307         if (!wg->peer_hashtable)
 308                 return ret;
 309
 310         wg->index_hashtable = wg_index_hashtable_alloc();
 311         if (!wg->index_hashtable)
 312                 goto err_free_peer_hashtable;
 313
 314         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
 315         if (!dev->tstats)
 316                 goto err_free_index_hashtable;
 317
 318         wg->incoming_handshakes_worker =
 319                 wg_packet_percpu_multicore_worker_alloc(
 320                                 wg_packet_handshake_receive_worker, wg);
 321         if (!wg->incoming_handshakes_worker)
 322                 goto err_free_tstats;
 323
 324         wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s",
 325                         WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name);
 326         if (!wg->handshake_receive_wq)
 327                 goto err_free_incoming_handshakes;
 328
 329         wg->handshake_send_wq = alloc_workqueue("wg-kex-%s",
 330                         WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name);
 331         if (!wg->handshake_send_wq)
 332                 goto err_destroy_handshake_receive;
 333
 334         wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s",
 335                         WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name);
 336         if (!wg->packet_crypt_wq)
 337                 goto err_destroy_handshake_send;
 338
 339         ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker,
 340                                    true, MAX_QUEUED_PACKETS);
 341         if (ret < 0)
 342                 goto err_destroy_packet_crypt;
 343
 344         ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker,
 345                                    true, MAX_QUEUED_PACKETS);
 346         if (ret < 0)
 347                 goto err_free_encrypt_queue;
 348
 349         ret = wg_ratelimiter_init();
 350         if (ret < 0)
 351                 goto err_free_decrypt_queue;
 352
 353         ret = register_netdevice(dev);
 354         if (ret < 0)
 355                 goto err_uninit_ratelimiter;
 356
 357         list_add(&wg->device_list, &device_list);
 358
 359         /* We wait until the end to assign priv_destructor, so that
 360          * register_netdevice doesn't call it for us if it fails.
 361          */
 362         dev->priv_destructor = wg_destruct;
 363
 364         pr_debug("%s: Interface created\n", dev->name);
 365         return ret;
 366
 367 err_uninit_ratelimiter:
 368         wg_ratelimiter_uninit();
 369 err_free_decrypt_queue:
 370         wg_packet_queue_free(&wg->decrypt_queue, true);
 371 err_free_encrypt_queue:
 372         wg_packet_queue_free(&wg->encrypt_queue, true);
 373 err_destroy_packet_crypt:
 374         destroy_workqueue(wg->packet_crypt_wq);
 375 err_destroy_handshake_send:
 376         destroy_workqueue(wg->handshake_send_wq);
 377 err_destroy_handshake_receive:
 378         destroy_workqueue(wg->handshake_receive_wq);
 379 err_free_incoming_handshakes:
 380         free_percpu(wg->incoming_handshakes_worker);
 381 err_free_tstats:
 382         free_percpu(dev->tstats);
 383 err_free_index_hashtable:
 384         kvfree(wg->index_hashtable);
 385 err_free_peer_hashtable:
 386         kvfree(wg->peer_hashtable);
 387         return ret;
 388 }
 389
 390 static struct rtnl_link_ops link_ops __read_mostly = {
 391         .kind                   = KBUILD_MODNAME,
 392         .priv_size              = sizeof(struct wg_device),
 393         .setup                  = wg_setup,
 394         .newlink                = wg_newlink,
 395 };
 396
 397 static void wg_netns_pre_exit(struct net *net)
 398 {
 399         struct wg_device *wg;
 400
 401         rtnl_lock();
 402         list_for_each_entry(wg, &device_list, device_list) {
 403                 if (rcu_access_pointer(wg->creating_net) == net) {
 404                         pr_debug("%s: Creating namespace exiting\n", wg->dev->name);
 405                         netif_carrier_off(wg->dev);
 406                         mutex_lock(&wg->device_update_lock);
 407                         rcu_assign_pointer(wg->creating_net, NULL);
 408                         wg_socket_reinit(wg, NULL, NULL);
 409                         mutex_unlock(&wg->device_update_lock);
 410                 }
 411         }
 412         rtnl_unlock();
 413 }
 414
 415 static struct pernet_operations pernet_ops = {
 416         .pre_exit = wg_netns_pre_exit
 417 };
 418
 419 int __init wg_device_init(void)
 420 {
 421         int ret;
 422
 423 #ifdef CONFIG_PM_SLEEP
 424         ret = register_pm_notifier(&pm_notifier);
 425         if (ret)
 426                 return ret;
 427 #endif
 428
 429         ret = register_pernet_device(&pernet_ops);
 430         if (ret)
 431                 goto error_pm;
 432
 433         ret = rtnl_link_register(&link_ops);
 434         if (ret)
 435                 goto error_pernet;
 436
 437         return 0;
 438
 439 error_pernet:
 440         unregister_pernet_device(&pernet_ops);
 441 error_pm:
 442 #ifdef CONFIG_PM_SLEEP
 443         unregister_pm_notifier(&pm_notifier);
 444 #endif
 445         return ret;
 446 }
 447
 448 void wg_device_uninit(void)
 449 {
 450         rtnl_link_unregister(&link_ops);
 451         unregister_pernet_device(&pernet_ops);
 452 #ifdef CONFIG_PM_SLEEP
 453         unregister_pm_notifier(&pm_notifier);
 454 #endif
 455         rcu_barrier();
 456 }