drivers/net/wireguard/device.c

   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 #ifdef CONFIG_PM_SLEEP
  64 static int wg_pm_notification(struct notifier_block *nb, unsigned long action,
  65                               void *data)
  66 {
  67         struct wg_device *wg;
  68         struct wg_peer *peer;
  69
  70         /* If the machine is constantly suspending and resuming, as part of
  71          * its normal operation rather than as a somewhat rare event, then we
  72          * don't actually want to clear keys.
  73          */
  74         if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || IS_ENABLED(CONFIG_ANDROID))
  75                 return 0;
  76
  77         if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE)
  78                 return 0;
  79
  80         rtnl_lock();
  81         list_for_each_entry(wg, &device_list, device_list) {
  82                 mutex_lock(&wg->device_update_lock);
  83                 list_for_each_entry(peer, &wg->peer_list, peer_list) {
  84                         del_timer(&peer->timer_zero_key_material);
  85                         wg_noise_handshake_clear(&peer->handshake);
  86                         wg_noise_keypairs_clear(&peer->keypairs);
  87                 }
  88                 mutex_unlock(&wg->device_update_lock);
  89         }
  90         rtnl_unlock();
  91         rcu_barrier();
  92         return 0;
  93 }
  94
  95 static struct notifier_block pm_notifier = { .notifier_call = wg_pm_notification };
  96 #endif
  97
  98 static int wg_stop(struct net_device *dev)
  99 {
 100         struct wg_device *wg = netdev_priv(dev);
 101         struct wg_peer *peer;
 102         struct sk_buff *skb;
 103
 104         mutex_lock(&wg->device_update_lock);
 105         list_for_each_entry(peer, &wg->peer_list, peer_list) {
 106                 wg_packet_purge_staged_packets(peer);
 107                 wg_timers_stop(peer);
 108                 wg_noise_handshake_clear(&peer->handshake);
 109                 wg_noise_keypairs_clear(&peer->keypairs);
 110                 wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake);
 111         }
 112         mutex_unlock(&wg->device_update_lock);
 113         while ((skb = ptr_ring_consume(&wg->handshake_queue.ring)) != NULL)
 114                 kfree_skb(skb);
 115         atomic_set(&wg->handshake_queue_len, 0);
 116         wg_socket_reinit(wg, NULL, NULL);
 117         return 0;
 118 }
 119
 120 static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 121 {
 122         struct wg_device *wg = netdev_priv(dev);
 123         struct sk_buff_head packets;
 124         struct wg_peer *peer;
 125         struct sk_buff *next;
 126         sa_family_t family;
 127         u32 mtu;
 128         int ret;
 129
 130         if (unlikely(!wg_check_packet_protocol(skb))) {
 131                 ret = -EPROTONOSUPPORT;
 132                 net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name);
 133                 goto err;
 134         }
 135
 136         peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb);
 137         if (unlikely(!peer)) {
 138                 ret = -ENOKEY;
 139                 if (skb->protocol == htons(ETH_P_IP))
 140                         net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n",
 141                                             dev->name, &ip_hdr(skb)->daddr);
 142                 else if (skb->protocol == htons(ETH_P_IPV6))
 143                         net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n",
 144                                             dev->name, &ipv6_hdr(skb)->daddr);
 145                 goto err_icmp;
 146         }
 147
 148         family = READ_ONCE(peer->endpoint.addr.sa_family);
 149         if (unlikely(family != AF_INET && family != AF_INET6)) {
 150                 ret = -EDESTADDRREQ;
 151                 net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n",
 152                                     dev->name, peer->internal_id);
 153                 goto err_peer;
 154         }
 155
 156         mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 157
 158         __skb_queue_head_init(&packets);
 159         if (!skb_is_gso(skb)) {
 160                 skb_mark_not_on_list(skb);
 161         } else {
 162                 struct sk_buff *segs = skb_gso_segment(skb, 0);
 163
 164                 if (unlikely(IS_ERR(segs))) {
 165                         ret = PTR_ERR(segs);
 166                         goto err_peer;
 167                 }
 168                 dev_kfree_skb(skb);
 169                 skb = segs;
 170         }
 171
 172         skb_list_walk_safe(skb, skb, next) {
 173                 skb_mark_not_on_list(skb);
 174
 175                 skb = skb_share_check(skb, GFP_ATOMIC);
 176                 if (unlikely(!skb))
 177                         continue;
 178
 179                 /* We only need to keep the original dst around for icmp,
 180                  * so at this point we're in a position to drop it.
 181                  */
 182                 skb_dst_drop(skb);
 183
 184                 PACKET_CB(skb)->mtu = mtu;
 185
 186                 __skb_queue_tail(&packets, skb);
 187         }
 188
 189         spin_lock_bh(&peer->staged_packet_queue.lock);
 190         /* If the queue is getting too big, we start removing the oldest packets
 191          * until it's small again. We do this before adding the new packet, so
 192          * we don't remove GSO segments that are in excess.
 193          */
 194         while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) {
 195                 dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue));
 196                 DEV_STATS_INC(dev, tx_dropped);
 197         }
 198         skb_queue_splice_tail(&packets, &peer->staged_packet_queue);
 199         spin_unlock_bh(&peer->staged_packet_queue.lock);
 200
 201         wg_packet_send_staged_packets(peer);
 202
 203         wg_peer_put(peer);
 204         return NETDEV_TX_OK;
 205
 206 err_peer:
 207         wg_peer_put(peer);
 208 err_icmp:
 209         if (skb->protocol == htons(ETH_P_IP))
 210                 icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
 211         else if (skb->protocol == htons(ETH_P_IPV6))
 212                 icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
 213 err:
 214         DEV_STATS_INC(dev, tx_errors);
 215         kfree_skb(skb);
 216         return ret;
 217 }
 218
 219 static const struct net_device_ops netdev_ops = {
 220         .ndo_open               = wg_open,
 221         .ndo_stop               = wg_stop,
 222         .ndo_start_xmit         = wg_xmit,
 223         .ndo_get_stats64        = ip_tunnel_get_stats64
 224 };
 225
 226 static void wg_destruct(struct net_device *dev)
 227 {
 228         struct wg_device *wg = netdev_priv(dev);
 229
 230         rtnl_lock();
 231         list_del(&wg->device_list);
 232         rtnl_unlock();
 233         mutex_lock(&wg->device_update_lock);
 234         rcu_assign_pointer(wg->creating_net, NULL);
 235         wg->incoming_port = 0;
 236         wg_socket_reinit(wg, NULL, NULL);
 237         /* The final references are cleared in the below calls to destroy_workqueue. */
 238         wg_peer_remove_all(wg);
 239         destroy_workqueue(wg->handshake_receive_wq);
 240         destroy_workqueue(wg->handshake_send_wq);
 241         destroy_workqueue(wg->packet_crypt_wq);
 242         wg_packet_queue_free(&wg->handshake_queue, true);
 243         wg_packet_queue_free(&wg->decrypt_queue, false);
 244         wg_packet_queue_free(&wg->encrypt_queue, false);
 245         rcu_barrier(); /* Wait for all the peers to be actually freed. */
 246         wg_ratelimiter_uninit();
 247         memzero_explicit(&wg->static_identity, sizeof(wg->static_identity));
 248         free_percpu(dev->tstats);
 249         kvfree(wg->index_hashtable);
 250         kvfree(wg->peer_hashtable);
 251         mutex_unlock(&wg->device_update_lock);
 252
 253         pr_debug("%s: Interface destroyed\n", dev->name);
 254         free_netdev(dev);
 255 }
 256
 257 static const struct device_type device_type = { .name = KBUILD_MODNAME };
 258
 259 static void wg_setup(struct net_device *dev)
 260 {
 261         struct wg_device *wg = netdev_priv(dev);
 262         enum { WG_NETDEV_FEATURES = NETIF_F_HW_CSUM | NETIF_F_RXCSUM |
 263                                     NETIF_F_SG | NETIF_F_GSO |
 264                                     NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA };
 265         const int overhead = MESSAGE_MINIMUM_LENGTH + sizeof(struct udphdr) +
 266                              max(sizeof(struct ipv6hdr), sizeof(struct iphdr));
 267
 268         dev->netdev_ops = &netdev_ops;
 269         dev->header_ops = &ip_tunnel_header_ops;
 270         dev->hard_header_len = 0;
 271         dev->addr_len = 0;
 272         dev->needed_headroom = DATA_PACKET_HEAD_ROOM;
 273         dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE);
 274         dev->type = ARPHRD_NONE;
 275         dev->flags = IFF_POINTOPOINT | IFF_NOARP;
 276         dev->priv_flags |= IFF_NO_QUEUE;
 277         dev->features |= NETIF_F_LLTX;
 278         dev->features |= WG_NETDEV_FEATURES;
 279         dev->hw_features |= WG_NETDEV_FEATURES;
 280         dev->hw_enc_features |= WG_NETDEV_FEATURES;
 281         dev->mtu = ETH_DATA_LEN - overhead;
 282         dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead;
 283
 284         SET_NETDEV_DEVTYPE(dev, &device_type);
 285
 286         /* We need to keep the dst around in case of icmp replies. */
 287         netif_keep_dst(dev);
 288
 289         memset(wg, 0, sizeof(*wg));
 290         wg->dev = dev;
 291 }
 292
 293 static int wg_newlink(struct net *src_net, struct net_device *dev,
 294                       struct nlattr *tb[], struct nlattr *data[],
 295                       struct netlink_ext_ack *extack)
 296 {
 297         struct wg_device *wg = netdev_priv(dev);
 298         int ret = -ENOMEM;
 299
 300         rcu_assign_pointer(wg->creating_net, src_net);
 301         init_rwsem(&wg->static_identity.lock);
 302         mutex_init(&wg->socket_update_lock);
 303         mutex_init(&wg->device_update_lock);
 304         wg_allowedips_init(&wg->peer_allowedips);
 305         wg_cookie_checker_init(&wg->cookie_checker, wg);
 306         INIT_LIST_HEAD(&wg->peer_list);
 307         wg->device_update_gen = 1;
 308
 309         wg->peer_hashtable = wg_pubkey_hashtable_alloc();
 310         if (!wg->peer_hashtable)
 311                 return ret;
 312
 313         wg->index_hashtable = wg_index_hashtable_alloc();
 314         if (!wg->index_hashtable)
 315                 goto err_free_peer_hashtable;
 316
 317         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
 318         if (!dev->tstats)
 319                 goto err_free_index_hashtable;
 320
 321         wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s",
 322                         WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name);
 323         if (!wg->handshake_receive_wq)
 324                 goto err_free_tstats;
 325
 326         wg->handshake_send_wq = alloc_workqueue("wg-kex-%s",
 327                         WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name);
 328         if (!wg->handshake_send_wq)
 329                 goto err_destroy_handshake_receive;
 330
 331         wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s",
 332                         WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name);
 333         if (!wg->packet_crypt_wq)
 334                 goto err_destroy_handshake_send;
 335
 336         ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker,
 337                                    MAX_QUEUED_PACKETS);
 338         if (ret < 0)
 339                 goto err_destroy_packet_crypt;
 340
 341         ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker,
 342                                    MAX_QUEUED_PACKETS);
 343         if (ret < 0)
 344                 goto err_free_encrypt_queue;
 345
 346         ret = wg_packet_queue_init(&wg->handshake_queue, wg_packet_handshake_receive_worker,
 347                                    MAX_QUEUED_INCOMING_HANDSHAKES);
 348         if (ret < 0)
 349                 goto err_free_decrypt_queue;
 350
 351         ret = wg_ratelimiter_init();
 352         if (ret < 0)
 353                 goto err_free_handshake_queue;
 354
 355         ret = register_netdevice(dev);
 356         if (ret < 0)
 357                 goto err_uninit_ratelimiter;
 358
 359         list_add(&wg->device_list, &device_list);
 360
 361         /* We wait until the end to assign priv_destructor, so that
 362          * register_netdevice doesn't call it for us if it fails.
 363          */
 364         dev->priv_destructor = wg_destruct;
 365
 366         pr_debug("%s: Interface created\n", dev->name);
 367         return ret;
 368
 369 err_uninit_ratelimiter:
 370         wg_ratelimiter_uninit();
 371 err_free_handshake_queue:
 372         wg_packet_queue_free(&wg->handshake_queue, false);
 373 err_free_decrypt_queue:
 374         wg_packet_queue_free(&wg->decrypt_queue, false);
 375 err_free_encrypt_queue:
 376         wg_packet_queue_free(&wg->encrypt_queue, false);
 377 err_destroy_packet_crypt:
 378         destroy_workqueue(wg->packet_crypt_wq);
 379 err_destroy_handshake_send:
 380         destroy_workqueue(wg->handshake_send_wq);
 381 err_destroy_handshake_receive:
 382         destroy_workqueue(wg->handshake_receive_wq);
 383 err_free_tstats:
 384         free_percpu(dev->tstats);
 385 err_free_index_hashtable:
 386         kvfree(wg->index_hashtable);
 387 err_free_peer_hashtable:
 388         kvfree(wg->peer_hashtable);
 389         return ret;
 390 }
 391
 392 static struct rtnl_link_ops link_ops __read_mostly = {
 393         .kind                   = KBUILD_MODNAME,
 394         .priv_size              = sizeof(struct wg_device),
 395         .setup                  = wg_setup,
 396         .newlink                = wg_newlink,
 397 };
 398
 399 static void wg_netns_pre_exit(struct net *net)
 400 {
 401         struct wg_device *wg;
 402         struct wg_peer *peer;
 403
 404         rtnl_lock();
 405         list_for_each_entry(wg, &device_list, device_list) {
 406                 if (rcu_access_pointer(wg->creating_net) == net) {
 407                         pr_debug("%s: Creating namespace exiting\n", wg->dev->name);
 408                         netif_carrier_off(wg->dev);
 409                         mutex_lock(&wg->device_update_lock);
 410                         rcu_assign_pointer(wg->creating_net, NULL);
 411                         wg_socket_reinit(wg, NULL, NULL);
 412                         list_for_each_entry(peer, &wg->peer_list, peer_list)
 413                                 wg_socket_clear_peer_endpoint_src(peer);
 414                         mutex_unlock(&wg->device_update_lock);
 415                 }
 416         }
 417         rtnl_unlock();
 418 }
 419
 420 static struct pernet_operations pernet_ops = {
 421         .pre_exit = wg_netns_pre_exit
 422 };
 423
 424 int __init wg_device_init(void)
 425 {
 426         int ret;
 427
 428 #ifdef CONFIG_PM_SLEEP
 429         ret = register_pm_notifier(&pm_notifier);
 430         if (ret)
 431                 return ret;
 432 #endif
 433
 434         ret = register_pernet_device(&pernet_ops);
 435         if (ret)
 436                 goto error_pm;
 437
 438         ret = rtnl_link_register(&link_ops);
 439         if (ret)
 440                 goto error_pernet;
 441
 442         return 0;
 443
 444 error_pernet:
 445         unregister_pernet_device(&pernet_ops);
 446 error_pm:
 447 #ifdef CONFIG_PM_SLEEP
 448         unregister_pm_notifier(&pm_notifier);
 449 #endif
 450         return ret;
 451 }
 452
 453 void wg_device_uninit(void)
 454 {
 455         rtnl_link_unregister(&link_ops);
 456         unregister_pernet_device(&pernet_ops);
 457 #ifdef CONFIG_PM_SLEEP
 458         unregister_pm_notifier(&pm_notifier);
 459 #endif
 460         rcu_barrier();
 461 }