// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2015-2019 Jason A. Donenfeld . All Rights Reserved. */ #include "netlink.h" #include "device.h" #include "peer.h" #include "socket.h" #include "queueing.h" #include "messages.h" #include #include #include #include #include static struct genl_family genl_family; static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = { [WGDEVICE_A_IFINDEX] = { .type = NLA_U32 }, [WGDEVICE_A_IFNAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 }, [WGDEVICE_A_PRIVATE_KEY] = NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN), [WGDEVICE_A_PUBLIC_KEY] = NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN), [WGDEVICE_A_FLAGS] = { .type = NLA_U32 }, [WGDEVICE_A_LISTEN_PORT] = { .type = NLA_U16 }, [WGDEVICE_A_FWMARK] = { .type = NLA_U32 }, [WGDEVICE_A_PEERS] = { .type = NLA_NESTED } }; static const struct nla_policy peer_policy[WGPEER_A_MAX + 1] = { [WGPEER_A_PUBLIC_KEY] = NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN), [WGPEER_A_PRESHARED_KEY] = NLA_POLICY_EXACT_LEN(NOISE_SYMMETRIC_KEY_LEN), [WGPEER_A_FLAGS] = { .type = NLA_U32 }, [WGPEER_A_ENDPOINT] = NLA_POLICY_MIN_LEN(sizeof(struct sockaddr)), [WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL] = { .type = NLA_U16 }, [WGPEER_A_LAST_HANDSHAKE_TIME] = NLA_POLICY_EXACT_LEN(sizeof(struct __kernel_timespec)), [WGPEER_A_RX_BYTES] = { .type = NLA_U64 }, [WGPEER_A_TX_BYTES] = { .type = NLA_U64 }, [WGPEER_A_ALLOWEDIPS] = { .type = NLA_NESTED }, [WGPEER_A_PROTOCOL_VERSION] = { .type = NLA_U32 } }; static const struct nla_policy allowedip_policy[WGALLOWEDIP_A_MAX + 1] = { [WGALLOWEDIP_A_FAMILY] = { .type = NLA_U16 }, [WGALLOWEDIP_A_IPADDR] = NLA_POLICY_MIN_LEN(sizeof(struct in_addr)), [WGALLOWEDIP_A_CIDR_MASK] = { .type = NLA_U8 } }; static struct wg_device *lookup_interface(struct nlattr **attrs, struct sk_buff *skb) { struct net_device *dev = NULL; if (!attrs[WGDEVICE_A_IFINDEX] == !attrs[WGDEVICE_A_IFNAME]) return ERR_PTR(-EBADR); if (attrs[WGDEVICE_A_IFINDEX]) dev = dev_get_by_index(sock_net(skb->sk), nla_get_u32(attrs[WGDEVICE_A_IFINDEX])); else if (attrs[WGDEVICE_A_IFNAME]) dev = dev_get_by_name(sock_net(skb->sk), nla_data(attrs[WGDEVICE_A_IFNAME])); if (!dev) return ERR_PTR(-ENODEV); if (!dev->rtnl_link_ops || !dev->rtnl_link_ops->kind || strcmp(dev->rtnl_link_ops->kind, KBUILD_MODNAME)) { dev_put(dev); return ERR_PTR(-EOPNOTSUPP); } return netdev_priv(dev); } static int get_allowedips(struct sk_buff *skb, const u8 *ip, u8 cidr, int family) { struct nlattr *allowedip_nest; allowedip_nest = nla_nest_start(skb, 0); if (!allowedip_nest) return -EMSGSIZE; if (nla_put_u8(skb, WGALLOWEDIP_A_CIDR_MASK, cidr) || nla_put_u16(skb, WGALLOWEDIP_A_FAMILY, family) || nla_put(skb, WGALLOWEDIP_A_IPADDR, family == AF_INET6 ? sizeof(struct in6_addr) : sizeof(struct in_addr), ip)) { nla_nest_cancel(skb, allowedip_nest); return -EMSGSIZE; } nla_nest_end(skb, allowedip_nest); return 0; } struct dump_ctx { struct wg_device *wg; struct wg_peer *next_peer; u64 allowedips_seq; struct allowedips_node *next_allowedip; }; #define DUMP_CTX(cb) ((struct dump_ctx *)(cb)->args) static int get_peer(struct wg_peer *peer, struct sk_buff *skb, struct dump_ctx *ctx) { struct nlattr *allowedips_nest, *peer_nest = nla_nest_start(skb, 0); struct allowedips_node *allowedips_node = ctx->next_allowedip; bool fail; if (!peer_nest) return -EMSGSIZE; down_read(&peer->handshake.lock); fail = nla_put(skb, WGPEER_A_PUBLIC_KEY, NOISE_PUBLIC_KEY_LEN, peer->handshake.remote_static); up_read(&peer->handshake.lock); if (fail) goto err; if (!allowedips_node) { const struct __kernel_timespec last_handshake = { .tv_sec = peer->walltime_last_handshake.tv_sec, .tv_nsec = peer->walltime_last_handshake.tv_nsec }; down_read(&peer->handshake.lock); fail = nla_put(skb, WGPEER_A_PRESHARED_KEY, NOISE_SYMMETRIC_KEY_LEN, peer->handshake.preshared_key); up_read(&peer->handshake.lock); if (fail) goto err; if (nla_put(skb, WGPEER_A_LAST_HANDSHAKE_TIME, sizeof(last_handshake), &last_handshake) || nla_put_u16(skb, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL, peer->persistent_keepalive_interval) || nla_put_u64_64bit(skb, WGPEER_A_TX_BYTES, peer->tx_bytes, WGPEER_A_UNSPEC) || nla_put_u64_64bit(skb, WGPEER_A_RX_BYTES, peer->rx_bytes, WGPEER_A_UNSPEC) || nla_put_u32(skb, WGPEER_A_PROTOCOL_VERSION, 1)) goto err; read_lock_bh(&peer->endpoint_lock); if (peer->endpoint.addr.sa_family == AF_INET) fail = nla_put(skb, WGPEER_A_ENDPOINT, sizeof(peer->endpoint.addr4), &peer->endpoint.addr4); else if (peer->endpoint.addr.sa_family == AF_INET6) fail = nla_put(skb, WGPEER_A_ENDPOINT, sizeof(peer->endpoint.addr6), &peer->endpoint.addr6); read_unlock_bh(&peer->endpoint_lock); if (fail) goto err; allowedips_node = list_first_entry_or_null(&peer->allowedips_list, struct allowedips_node, peer_list); } if (!allowedips_node) goto no_allowedips; if (!ctx->allowedips_seq) ctx->allowedips_seq = peer->device->peer_allowedips.seq; else if (ctx->allowedips_seq != peer->device->peer_allowedips.seq) goto no_allowedips; allowedips_nest = nla_nest_start(skb, WGPEER_A_ALLOWEDIPS); if (!allowedips_nest) goto err; list_for_each_entry_from(allowedips_node, &peer->allowedips_list, peer_list) { u8 cidr, ip[16] __aligned(__alignof(u64)); int family; family = wg_allowedips_read_node(allowedips_node, ip, &cidr); if (get_allowedips(skb, ip, cidr, family)) { nla_nest_end(skb, allowedips_nest); nla_nest_end(skb, peer_nest); ctx->next_allowedip = allowedips_node; return -EMSGSIZE; } } nla_nest_end(skb, allowedips_nest); no_allowedips: nla_nest_end(skb, peer_nest); ctx->next_allowedip = NULL; ctx->allowedips_seq = 0; return 0; err: nla_nest_cancel(skb, peer_nest); return -EMSGSIZE; } static int wg_get_device_start(struct netlink_callback *cb) { struct wg_device *wg; wg = lookup_interface(genl_dumpit_info(cb)->attrs, cb->skb); if (IS_ERR(wg)) return PTR_ERR(wg); DUMP_CTX(cb)->wg = wg; return 0; } static int wg_get_device_dump(struct sk_buff *skb, struct netlink_callback *cb) { struct wg_peer *peer, *next_peer_cursor; struct dump_ctx *ctx = DUMP_CTX(cb); struct wg_device *wg = ctx->wg; struct nlattr *peers_nest; int ret = -EMSGSIZE; bool done = true; void *hdr; rtnl_lock(); mutex_lock(&wg->device_update_lock); cb->seq = wg->device_update_gen; next_peer_cursor = ctx->next_peer; hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, &genl_family, NLM_F_MULTI, WG_CMD_GET_DEVICE); if (!hdr) goto out; genl_dump_check_consistent(cb, hdr); if (!ctx->next_peer) { if (nla_put_u16(skb, WGDEVICE_A_LISTEN_PORT, wg->incoming_port) || nla_put_u32(skb, WGDEVICE_A_FWMARK, wg->fwmark) || nla_put_u32(skb, WGDEVICE_A_IFINDEX, wg->dev->ifindex) || nla_put_string(skb, WGDEVICE_A_IFNAME, wg->dev->name)) goto out; down_read(&wg->static_identity.lock); if (wg->static_identity.has_identity) { if (nla_put(skb, WGDEVICE_A_PRIVATE_KEY, NOISE_PUBLIC_KEY_LEN, wg->static_identity.static_private) || nla_put(skb, WGDEVICE_A_PUBLIC_KEY, NOISE_PUBLIC_KEY_LEN, wg->static_identity.static_public)) { up_read(&wg->static_identity.lock); goto out; } } up_read(&wg->static_identity.lock); } peers_nest = nla_nest_start(skb, WGDEVICE_A_PEERS); if (!peers_nest) goto out; ret = 0; /* If the last cursor was removed via list_del_init in peer_remove, then * we just treat this the same as there being no more peers left. The * reason is that seq_nr should indicate to userspace that this isn't a * coherent dump anyway, so they'll try again. */ if (list_empty(&wg->peer_list) || (ctx->next_peer && list_empty(&ctx->next_peer->peer_list))) { nla_nest_cancel(skb, peers_nest); goto out; } lockdep_assert_held(&wg->device_update_lock); peer = list_prepare_entry(ctx->next_peer, &wg->peer_list, peer_list); list_for_each_entry_continue(peer, &wg->peer_list, peer_list) { if (get_peer(peer, skb, ctx)) { done = false; break; } next_peer_cursor = peer; } nla_nest_end(skb, peers_nest); out: if (!ret && !done && next_peer_cursor) wg_peer_get(next_peer_cursor); wg_peer_put(ctx->next_peer); mutex_unlock(&wg->device_update_lock); rtnl_unlock(); if (ret) { genlmsg_cancel(skb, hdr); return ret; } genlmsg_end(skb, hdr); if (done) { ctx->next_peer = NULL; return 0; } ctx->next_peer = next_peer_cursor; return skb->len; /* At this point, we can't really deal ourselves with safely zeroing out * the private key material after usage. This will need an additional API * in the kernel for marking skbs as zero_on_free. */ } static int wg_get_device_done(struct netlink_callback *cb) { struct dump_ctx *ctx = DUMP_CTX(cb); if (ctx->wg) dev_put(ctx->wg->dev); wg_peer_put(ctx->next_peer); return 0; } static int set_port(struct wg_device *wg, u16 port) { struct wg_peer *peer; if (wg->incoming_port == port) return 0; list_for_each_entry(peer, &wg->peer_list, peer_list) wg_socket_clear_peer_endpoint_src(peer); if (!netif_running(wg->dev)) { wg->incoming_port = port; return 0; } return wg_socket_init(wg, port); } static int set_allowedip(struct wg_peer *peer, struct nlattr **attrs) { int ret = -EINVAL; u16 family; u8 cidr; if (!attrs[WGALLOWEDIP_A_FAMILY] || !attrs[WGALLOWEDIP_A_IPADDR] || !attrs[WGALLOWEDIP_A_CIDR_MASK]) return ret; family = nla_get_u16(attrs[WGALLOWEDIP_A_FAMILY]); cidr = nla_get_u8(attrs[WGALLOWEDIP_A_CIDR_MASK]); if (family == AF_INET && cidr <= 32 && nla_len(attrs[WGALLOWEDIP_A_IPADDR]) == sizeof(struct in_addr)) ret = wg_allowedips_insert_v4( &peer->device->peer_allowedips, nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, peer, &peer->device->device_update_lock); else if (family == AF_INET6 && cidr <= 128 && nla_len(attrs[WGALLOWEDIP_A_IPADDR]) == sizeof(struct in6_addr)) ret = wg_allowedips_insert_v6( &peer->device->peer_allowedips, nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, peer, &peer->device->device_update_lock); return ret; } static int set_peer(struct wg_device *wg, struct nlattr **attrs) { u8 *public_key = NULL, *preshared_key = NULL; struct wg_peer *peer = NULL; u32 flags = 0; int ret; ret = -EINVAL; if (attrs[WGPEER_A_PUBLIC_KEY] && nla_len(attrs[WGPEER_A_PUBLIC_KEY]) == NOISE_PUBLIC_KEY_LEN) public_key = nla_data(attrs[WGPEER_A_PUBLIC_KEY]); else goto out; if (attrs[WGPEER_A_PRESHARED_KEY] && nla_len(attrs[WGPEER_A_PRESHARED_KEY]) == NOISE_SYMMETRIC_KEY_LEN) preshared_key = nla_data(attrs[WGPEER_A_PRESHARED_KEY]); if (attrs[WGPEER_A_FLAGS]) flags = nla_get_u32(attrs[WGPEER_A_FLAGS]); ret = -EOPNOTSUPP; if (flags & ~__WGPEER_F_ALL) goto out; ret = -EPFNOSUPPORT; if (attrs[WGPEER_A_PROTOCOL_VERSION]) { if (nla_get_u32(attrs[WGPEER_A_PROTOCOL_VERSION]) != 1) goto out; } peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, nla_data(attrs[WGPEER_A_PUBLIC_KEY])); ret = 0; if (!peer) { /* Peer doesn't exist yet. Add a new one. */ if (flags & (WGPEER_F_REMOVE_ME | WGPEER_F_UPDATE_ONLY)) goto out; /* The peer is new, so there aren't allowed IPs to remove. */ flags &= ~WGPEER_F_REPLACE_ALLOWEDIPS; down_read(&wg->static_identity.lock); if (wg->static_identity.has_identity && !memcmp(nla_data(attrs[WGPEER_A_PUBLIC_KEY]), wg->static_identity.static_public, NOISE_PUBLIC_KEY_LEN)) { /* We silently ignore peers that have the same public * key as the device. The reason we do it silently is * that we'd like for people to be able to reuse the * same set of API calls across peers. */ up_read(&wg->static_identity.lock); ret = 0; goto out; } up_read(&wg->static_identity.lock); peer = wg_peer_create(wg, public_key, preshared_key); if (IS_ERR(peer)) { ret = PTR_ERR(peer); peer = NULL; goto out; } /* Take additional reference, as though we've just been * looked up. */ wg_peer_get(peer); } if (flags & WGPEER_F_REMOVE_ME) { wg_peer_remove(peer); goto out; } if (preshared_key) { down_write(&peer->handshake.lock); memcpy(&peer->handshake.preshared_key, preshared_key, NOISE_SYMMETRIC_KEY_LEN); up_write(&peer->handshake.lock); } if (attrs[WGPEER_A_ENDPOINT]) { struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]); size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]); struct endpoint endpoint = { { { 0 } } }; if (len == sizeof(struct sockaddr_in) && addr->sa_family == AF_INET) { endpoint.addr4 = *(struct sockaddr_in *)addr; wg_socket_set_peer_endpoint(peer, &endpoint); } else if (len == sizeof(struct sockaddr_in6) && addr->sa_family == AF_INET6) { endpoint.addr6 = *(struct sockaddr_in6 *)addr; wg_socket_set_peer_endpoint(peer, &endpoint); } } if (flags & WGPEER_F_REPLACE_ALLOWEDIPS) wg_allowedips_remove_by_peer(&wg->peer_allowedips, peer, &wg->device_update_lock); if (attrs[WGPEER_A_ALLOWEDIPS]) { struct nlattr *attr, *allowedip[WGALLOWEDIP_A_MAX + 1]; int rem; nla_for_each_nested(attr, attrs[WGPEER_A_ALLOWEDIPS], rem) { ret = nla_parse_nested(allowedip, WGALLOWEDIP_A_MAX, attr, allowedip_policy, NULL); if (ret < 0) goto out; ret = set_allowedip(peer, allowedip); if (ret < 0) goto out; } } if (attrs[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]) { const u16 persistent_keepalive_interval = nla_get_u16( attrs[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]); const bool send_keepalive = !peer->persistent_keepalive_interval && persistent_keepalive_interval && netif_running(wg->dev); peer->persistent_keepalive_interval = persistent_keepalive_interval; if (send_keepalive) wg_packet_send_keepalive(peer); } if (netif_running(wg->dev)) wg_packet_send_staged_packets(peer); out: wg_peer_put(peer); if (attrs[WGPEER_A_PRESHARED_KEY]) memzero_explicit(nla_data(attrs[WGPEER_A_PRESHARED_KEY]), nla_len(attrs[WGPEER_A_PRESHARED_KEY])); return ret; } static int wg_set_device(struct sk_buff *skb, struct genl_info *info) { struct wg_device *wg = lookup_interface(info->attrs, skb); u32 flags = 0; int ret; if (IS_ERR(wg)) { ret = PTR_ERR(wg); goto out_nodev; } rtnl_lock(); mutex_lock(&wg->device_update_lock); if (info->attrs[WGDEVICE_A_FLAGS]) flags = nla_get_u32(info->attrs[WGDEVICE_A_FLAGS]); ret = -EOPNOTSUPP; if (flags & ~__WGDEVICE_F_ALL) goto out; if (info->attrs[WGDEVICE_A_LISTEN_PORT] || info->attrs[WGDEVICE_A_FWMARK]) { struct net *net; rcu_read_lock(); net = rcu_dereference(wg->creating_net); ret = !net || !ns_capable(net->user_ns, CAP_NET_ADMIN) ? -EPERM : 0; rcu_read_unlock(); if (ret) goto out; } ++wg->device_update_gen; if (info->attrs[WGDEVICE_A_FWMARK]) { struct wg_peer *peer; wg->fwmark = nla_get_u32(info->attrs[WGDEVICE_A_FWMARK]); list_for_each_entry(peer, &wg->peer_list, peer_list) wg_socket_clear_peer_endpoint_src(peer); } if (info->attrs[WGDEVICE_A_LISTEN_PORT]) { ret = set_port(wg, nla_get_u16(info->attrs[WGDEVICE_A_LISTEN_PORT])); if (ret) goto out; } if (flags & WGDEVICE_F_REPLACE_PEERS) wg_peer_remove_all(wg); if (info->attrs[WGDEVICE_A_PRIVATE_KEY] && nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY]) == NOISE_PUBLIC_KEY_LEN) { u8 *private_key = nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]); u8 public_key[NOISE_PUBLIC_KEY_LEN]; struct wg_peer *peer, *temp; bool send_staged_packets; if (!crypto_memneq(wg->static_identity.static_private, private_key, NOISE_PUBLIC_KEY_LEN)) goto skip_set_private_key; /* We remove before setting, to prevent race, which means doing * two 25519-genpub ops. */ if (curve25519_generate_public(public_key, private_key)) { peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, public_key); if (peer) { wg_peer_put(peer); wg_peer_remove(peer); } } down_write(&wg->static_identity.lock); send_staged_packets = !wg->static_identity.has_identity && netif_running(wg->dev); wg_noise_set_static_identity_private_key(&wg->static_identity, private_key); send_staged_packets = send_staged_packets && wg->static_identity.has_identity; wg_cookie_checker_precompute_device_keys(&wg->cookie_checker); list_for_each_entry_safe(peer, temp, &wg->peer_list, peer_list) { wg_noise_precompute_static_static(peer); wg_noise_expire_current_peer_keypairs(peer); if (send_staged_packets) wg_packet_send_staged_packets(peer); } up_write(&wg->static_identity.lock); } skip_set_private_key: if (info->attrs[WGDEVICE_A_PEERS]) { struct nlattr *attr, *peer[WGPEER_A_MAX + 1]; int rem; nla_for_each_nested(attr, info->attrs[WGDEVICE_A_PEERS], rem) { ret = nla_parse_nested(peer, WGPEER_A_MAX, attr, peer_policy, NULL); if (ret < 0) goto out; ret = set_peer(wg, peer); if (ret < 0) goto out; } } ret = 0; out: mutex_unlock(&wg->device_update_lock); rtnl_unlock(); dev_put(wg->dev); out_nodev: if (info->attrs[WGDEVICE_A_PRIVATE_KEY]) memzero_explicit(nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]), nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY])); return ret; } static const struct genl_ops genl_ops[] = { { .cmd = WG_CMD_GET_DEVICE, .start = wg_get_device_start, .dumpit = wg_get_device_dump, .done = wg_get_device_done, .flags = GENL_UNS_ADMIN_PERM }, { .cmd = WG_CMD_SET_DEVICE, .doit = wg_set_device, .flags = GENL_UNS_ADMIN_PERM } }; static struct genl_family genl_family __ro_after_init = { .ops = genl_ops, .n_ops = ARRAY_SIZE(genl_ops), .name = WG_GENL_NAME, .version = WG_GENL_VERSION, .maxattr = WGDEVICE_A_MAX, .module = THIS_MODULE, .policy = device_policy, .netnsok = true }; int __init wg_genetlink_init(void) { return genl_register_family(&genl_family); } void __exit wg_genetlink_uninit(void) { genl_unregister_family(&genl_family); }