diff options
Diffstat (limited to 'vpn/plugins/libwireguard.c')
| -rw-r--r-- | vpn/plugins/libwireguard.c | 998 |
1 files changed, 998 insertions, 0 deletions
diff --git a/vpn/plugins/libwireguard.c b/vpn/plugins/libwireguard.c new file mode 100644 index 00000000..c1f55a72 --- /dev/null +++ b/vpn/plugins/libwireguard.c @@ -0,0 +1,998 @@ +// SPDX-License-Identifier: LGPL-2.1+ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * Copyright (C) 2008-2012 Pablo Neira Ayuso <pablo@netfilter.org>. + */ + +#define _GNU_SOURCE + +#include <errno.h> +#include <linux/genetlink.h> +#include <linux/if_link.h> +#include <linux/netlink.h> +#include <linux/rtnetlink.h> +#include <netinet/in.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/socket.h> +#include <time.h> +#include <unistd.h> +#include <fcntl.h> +#include <assert.h> + +#include <libmnl/libmnl.h> + +#include "src/shared/mnlg.h" +#include "wireguard.h" + +/* wireguard.h netlink uapi: */ + +#define WG_GENL_NAME "wireguard" +#define WG_GENL_VERSION 1 + +enum wg_cmd { + WG_CMD_GET_DEVICE, + WG_CMD_SET_DEVICE, + __WG_CMD_MAX +}; + +enum wgdevice_flag { + WGDEVICE_F_REPLACE_PEERS = 1U << 0 +}; +enum wgdevice_attribute { + WGDEVICE_A_UNSPEC, + WGDEVICE_A_IFINDEX, + WGDEVICE_A_IFNAME, + WGDEVICE_A_PRIVATE_KEY, + WGDEVICE_A_PUBLIC_KEY, + WGDEVICE_A_FLAGS, + WGDEVICE_A_LISTEN_PORT, + WGDEVICE_A_FWMARK, + WGDEVICE_A_PEERS, + __WGDEVICE_A_LAST +}; + +enum wgpeer_flag { + WGPEER_F_REMOVE_ME = 1U << 0, + WGPEER_F_REPLACE_ALLOWEDIPS = 1U << 1 +}; +enum wgpeer_attribute { + WGPEER_A_UNSPEC, + WGPEER_A_PUBLIC_KEY, + WGPEER_A_PRESHARED_KEY, + WGPEER_A_FLAGS, + WGPEER_A_ENDPOINT, + WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL, + WGPEER_A_LAST_HANDSHAKE_TIME, + WGPEER_A_RX_BYTES, + WGPEER_A_TX_BYTES, + WGPEER_A_ALLOWEDIPS, + WGPEER_A_PROTOCOL_VERSION, + __WGPEER_A_LAST +}; + +enum wgallowedip_attribute { + WGALLOWEDIP_A_UNSPEC, + WGALLOWEDIP_A_FAMILY, + WGALLOWEDIP_A_IPADDR, + WGALLOWEDIP_A_CIDR_MASK, + __WGALLOWEDIP_A_LAST +}; + +/* wireguard-specific parts: */ + +struct inflatable_buffer { + char *buffer; + char *next; + bool good; + size_t len; + size_t pos; +}; + +#define max(a, b) ((a) > (b) ? (a) : (b)) + +static int add_next_to_inflatable_buffer(struct inflatable_buffer *buffer) +{ + size_t len, expand_to; + char *new_buffer; + + if (!buffer->good || !buffer->next) { + free(buffer->next); + buffer->good = false; + return 0; + } + + len = strlen(buffer->next) + 1; + + if (len == 1) { + free(buffer->next); + buffer->good = false; + return 0; + } + + if (buffer->len - buffer->pos <= len) { + expand_to = max(buffer->len * 2, buffer->len + len + 1); + new_buffer = realloc(buffer->buffer, expand_to); + if (!new_buffer) { + free(buffer->next); + buffer->good = false; + return -errno; + } + memset(&new_buffer[buffer->len], 0, expand_to - buffer->len); + buffer->buffer = new_buffer; + buffer->len = expand_to; + } + memcpy(&buffer->buffer[buffer->pos], buffer->next, len); + free(buffer->next); + buffer->good = false; + buffer->pos += len; + return 0; +} + +static int parse_linkinfo(const struct nlattr *attr, void *data) +{ + struct inflatable_buffer *buffer = data; + + if (mnl_attr_get_type(attr) == IFLA_INFO_KIND && !strcmp(WG_GENL_NAME, mnl_attr_get_str(attr))) + buffer->good = true; + return MNL_CB_OK; +} + +static int parse_infomsg(const struct nlattr *attr, void *data) +{ + struct inflatable_buffer *buffer = data; + + if (mnl_attr_get_type(attr) == IFLA_LINKINFO) + return mnl_attr_parse_nested(attr, parse_linkinfo, data); + else if (mnl_attr_get_type(attr) == IFLA_IFNAME) + buffer->next = strdup(mnl_attr_get_str(attr)); + return MNL_CB_OK; +} + +static int read_devices_cb(const struct nlmsghdr *nlh, void *data) +{ + struct inflatable_buffer *buffer = data; + int ret; + + buffer->good = false; + buffer->next = NULL; + ret = mnl_attr_parse(nlh, sizeof(struct ifinfomsg), parse_infomsg, data); + if (ret != MNL_CB_OK) + return ret; + ret = add_next_to_inflatable_buffer(buffer); + if (ret < 0) + return ret; + if (nlh->nlmsg_type != NLMSG_DONE) + return MNL_CB_OK + 1; + return MNL_CB_OK; +} + +static int fetch_device_names(struct inflatable_buffer *buffer) +{ + struct mnl_socket *nl = NULL; + char *rtnl_buffer = NULL; + size_t message_len; + unsigned int portid, seq; + ssize_t len; + int ret = 0; + struct nlmsghdr *nlh; + struct ifinfomsg *ifm; + + ret = -ENOMEM; + rtnl_buffer = calloc(MNL_SOCKET_BUFFER_SIZE, 1); + if (!rtnl_buffer) + goto cleanup; + + nl = mnl_socket_open(NETLINK_ROUTE); + if (!nl) { + ret = -errno; + goto cleanup; + } + + if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) { + ret = -errno; + goto cleanup; + } + + seq = time(NULL); + portid = mnl_socket_get_portid(nl); + nlh = mnl_nlmsg_put_header(rtnl_buffer); + nlh->nlmsg_type = RTM_GETLINK; + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP; + nlh->nlmsg_seq = seq; + ifm = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifm)); + ifm->ifi_family = AF_UNSPEC; + message_len = nlh->nlmsg_len; + + if (mnl_socket_sendto(nl, rtnl_buffer, message_len) < 0) { + ret = -errno; + goto cleanup; + } + +another: + if ((len = mnl_socket_recvfrom(nl, rtnl_buffer, MNL_SOCKET_BUFFER_SIZE)) < 0) { + ret = -errno; + goto cleanup; + } + if ((len = mnl_cb_run(rtnl_buffer, len, seq, portid, read_devices_cb, buffer)) < 0) { + /* Netlink returns NLM_F_DUMP_INTR if the set of all tunnels changed + * during the dump. That's unfortunate, but is pretty common on busy + * systems that are adding and removing tunnels all the time. Rather + * than retrying, potentially indefinitely, we just work with the + * partial results. */ + if (errno != EINTR) { + ret = -errno; + goto cleanup; + } + } + if (len == MNL_CB_OK + 1) + goto another; + ret = 0; + +cleanup: + free(rtnl_buffer); + if (nl) + mnl_socket_close(nl); + return ret; +} + +static int add_del_iface(const char *ifname, bool add) +{ + struct mnl_socket *nl = NULL; + char *rtnl_buffer; + ssize_t len; + int ret; + struct nlmsghdr *nlh; + struct ifinfomsg *ifm; + struct nlattr *nest; + + rtnl_buffer = calloc(MNL_SOCKET_BUFFER_SIZE, 1); + if (!rtnl_buffer) { + ret = -ENOMEM; + goto cleanup; + } + + nl = mnl_socket_open(NETLINK_ROUTE); + if (!nl) { + ret = -errno; + goto cleanup; + } + + if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) { + ret = -errno; + goto cleanup; + } + + nlh = mnl_nlmsg_put_header(rtnl_buffer); + nlh->nlmsg_type = add ? RTM_NEWLINK : RTM_DELLINK; + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | (add ? NLM_F_CREATE | NLM_F_EXCL : 0); + nlh->nlmsg_seq = time(NULL); + ifm = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifm)); + ifm->ifi_family = AF_UNSPEC; + mnl_attr_put_strz(nlh, IFLA_IFNAME, ifname); + nest = mnl_attr_nest_start(nlh, IFLA_LINKINFO); + mnl_attr_put_strz(nlh, IFLA_INFO_KIND, WG_GENL_NAME); + mnl_attr_nest_end(nlh, nest); + + if (mnl_socket_sendto(nl, rtnl_buffer, nlh->nlmsg_len) < 0) { + ret = -errno; + goto cleanup; + } + if ((len = mnl_socket_recvfrom(nl, rtnl_buffer, MNL_SOCKET_BUFFER_SIZE)) < 0) { + ret = -errno; + goto cleanup; + } + if (mnl_cb_run(rtnl_buffer, len, nlh->nlmsg_seq, mnl_socket_get_portid(nl), NULL, NULL) < 0) { + ret = -errno; + goto cleanup; + } + ret = 0; + +cleanup: + free(rtnl_buffer); + if (nl) + mnl_socket_close(nl); + return ret; +} + +int wg_set_device(wg_device *dev) +{ + int ret = 0; + wg_peer *peer = NULL; + wg_allowedip *allowedip = NULL; + struct nlattr *peers_nest, *peer_nest, *allowedips_nest, *allowedip_nest; + struct nlmsghdr *nlh; + struct mnlg_socket *nlg; + + nlg = mnlg_socket_open(WG_GENL_NAME, WG_GENL_VERSION); + if (!nlg) + return -errno; + +again: + nlh = mnlg_msg_prepare(nlg, WG_CMD_SET_DEVICE, NLM_F_REQUEST | NLM_F_ACK); + mnl_attr_put_strz(nlh, WGDEVICE_A_IFNAME, dev->name); + + if (!peer) { + uint32_t flags = 0; + + if (dev->flags & WGDEVICE_HAS_PRIVATE_KEY) + mnl_attr_put(nlh, WGDEVICE_A_PRIVATE_KEY, sizeof(dev->private_key), dev->private_key); + if (dev->flags & WGDEVICE_HAS_LISTEN_PORT) + mnl_attr_put_u16(nlh, WGDEVICE_A_LISTEN_PORT, dev->listen_port); + if (dev->flags & WGDEVICE_HAS_FWMARK) + mnl_attr_put_u32(nlh, WGDEVICE_A_FWMARK, dev->fwmark); + if (dev->flags & WGDEVICE_REPLACE_PEERS) + flags |= WGDEVICE_F_REPLACE_PEERS; + if (flags) + mnl_attr_put_u32(nlh, WGDEVICE_A_FLAGS, flags); + } + if (!dev->first_peer) + goto send; + peers_nest = peer_nest = allowedips_nest = allowedip_nest = NULL; + peers_nest = mnl_attr_nest_start(nlh, WGDEVICE_A_PEERS); + for (peer = peer ? peer : dev->first_peer; peer; peer = peer->next_peer) { + uint32_t flags = 0; + + peer_nest = mnl_attr_nest_start_check(nlh, MNL_SOCKET_BUFFER_SIZE, 0); + if (!peer_nest) + goto toobig_peers; + if (!mnl_attr_put_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_PUBLIC_KEY, sizeof(peer->public_key), peer->public_key)) + goto toobig_peers; + if (peer->flags & WGPEER_REMOVE_ME) + flags |= WGPEER_F_REMOVE_ME; + if (!allowedip) { + if (peer->flags & WGPEER_REPLACE_ALLOWEDIPS) + flags |= WGPEER_F_REPLACE_ALLOWEDIPS; + if (peer->flags & WGPEER_HAS_PRESHARED_KEY) { + if (!mnl_attr_put_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_PRESHARED_KEY, sizeof(peer->preshared_key), peer->preshared_key)) + goto toobig_peers; + } + if (peer->endpoint.addr.sa_family == AF_INET) { + if (!mnl_attr_put_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_ENDPOINT, sizeof(peer->endpoint.addr4), &peer->endpoint.addr4)) + goto toobig_peers; + } else if (peer->endpoint.addr.sa_family == AF_INET6) { + if (!mnl_attr_put_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_ENDPOINT, sizeof(peer->endpoint.addr6), &peer->endpoint.addr6)) + goto toobig_peers; + } + if (peer->flags & WGPEER_HAS_PERSISTENT_KEEPALIVE_INTERVAL) { + if (!mnl_attr_put_u16_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL, peer->persistent_keepalive_interval)) + goto toobig_peers; + } + } + if (flags) { + if (!mnl_attr_put_u32_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_FLAGS, flags)) + goto toobig_peers; + } + if (peer->first_allowedip) { + if (!allowedip) + allowedip = peer->first_allowedip; + allowedips_nest = mnl_attr_nest_start_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGPEER_A_ALLOWEDIPS); + if (!allowedips_nest) + goto toobig_allowedips; + for (; allowedip; allowedip = allowedip->next_allowedip) { + allowedip_nest = mnl_attr_nest_start_check(nlh, MNL_SOCKET_BUFFER_SIZE, 0); + if (!allowedip_nest) + goto toobig_allowedips; + if (!mnl_attr_put_u16_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_FAMILY, allowedip->family)) + goto toobig_allowedips; + if (allowedip->family == AF_INET) { + if (!mnl_attr_put_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_IPADDR, sizeof(allowedip->ip4), &allowedip->ip4)) + goto toobig_allowedips; + } else if (allowedip->family == AF_INET6) { + if (!mnl_attr_put_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_IPADDR, sizeof(allowedip->ip6), &allowedip->ip6)) + goto toobig_allowedips; + } + if (!mnl_attr_put_u8_check(nlh, MNL_SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_CIDR_MASK, allowedip->cidr)) + goto toobig_allowedips; + mnl_attr_nest_end(nlh, allowedip_nest); + allowedip_nest = NULL; + } + mnl_attr_nest_end(nlh, allowedips_nest); + allowedips_nest = NULL; + } + + mnl_attr_nest_end(nlh, peer_nest); + peer_nest = NULL; + } + mnl_attr_nest_end(nlh, peers_nest); + peers_nest = NULL; + goto send; +toobig_allowedips: + if (allowedip_nest) + mnl_attr_nest_cancel(nlh, allowedip_nest); + if (allowedips_nest) + mnl_attr_nest_end(nlh, allowedips_nest); + mnl_attr_nest_end(nlh, peer_nest); + mnl_attr_nest_end(nlh, peers_nest); + goto send; +toobig_peers: + if (peer_nest) + mnl_attr_nest_cancel(nlh, peer_nest); + mnl_attr_nest_end(nlh, peers_nest); + goto send; +send: + if (mnlg_socket_send(nlg, nlh) < 0) { + ret = -errno; + goto out; + } + errno = 0; + if (mnlg_socket_recv_run(nlg, NULL, NULL) < 0) { + ret = errno ? -errno : -EINVAL; + goto out; + } + if (peer) + goto again; + +out: + mnlg_socket_close(nlg); + errno = -ret; + return ret; +} + +static int parse_allowedip(const struct nlattr *attr, void *data) +{ + wg_allowedip *allowedip = data; + + switch (mnl_attr_get_type(attr)) { + case WGALLOWEDIP_A_UNSPEC: + break; + case WGALLOWEDIP_A_FAMILY: + if (!mnl_attr_validate(attr, MNL_TYPE_U16)) + allowedip->family = mnl_attr_get_u16(attr); + break; + case WGALLOWEDIP_A_IPADDR: + if (mnl_attr_get_payload_len(attr) == sizeof(allowedip->ip4)) + memcpy(&allowedip->ip4, mnl_attr_get_payload(attr), sizeof(allowedip->ip4)); + else if (mnl_attr_get_payload_len(attr) == sizeof(allowedip->ip6)) + memcpy(&allowedip->ip6, mnl_attr_get_payload(attr), sizeof(allowedip->ip6)); + break; + case WGALLOWEDIP_A_CIDR_MASK: + if (!mnl_attr_validate(attr, MNL_TYPE_U8)) + allowedip->cidr = mnl_attr_get_u8(attr); + break; + } + + return MNL_CB_OK; +} + +static int parse_allowedips(const struct nlattr *attr, void *data) +{ + wg_peer *peer = data; + wg_allowedip *new_allowedip = calloc(1, sizeof(wg_allowedip)); + int ret; + + if (!new_allowedip) + return MNL_CB_ERROR; + if (!peer->first_allowedip) + peer->first_allowedip = peer->last_allowedip = new_allowedip; + else { + peer->last_allowedip->next_allowedip = new_allowedip; + peer->last_allowedip = new_allowedip; + } + ret = mnl_attr_parse_nested(attr, parse_allowedip, new_allowedip); + if (!ret) + return ret; + if (!((new_allowedip->family == AF_INET && new_allowedip->cidr <= 32) || (new_allowedip->family == AF_INET6 && new_allowedip->cidr <= 128))) { + errno = EAFNOSUPPORT; + return MNL_CB_ERROR; + } + return MNL_CB_OK; +} + +bool wg_key_is_zero(const wg_key key) +{ + volatile uint8_t acc = 0; + unsigned int i; + + for (i = 0; i < sizeof(wg_key); ++i) { + acc |= key[i]; + __asm__ ("" : "=r" (acc) : "0" (acc)); + } + return 1 & ((acc - 1) >> 8); +} + +static int parse_peer(const struct nlattr *attr, void *data) +{ + wg_peer *peer = data; + + switch (mnl_attr_get_type(attr)) { + case WGPEER_A_UNSPEC: + break; + case WGPEER_A_PUBLIC_KEY: + if (mnl_attr_get_payload_len(attr) == sizeof(peer->public_key)) { + memcpy(peer->public_key, mnl_attr_get_payload(attr), sizeof(peer->public_key)); + peer->flags |= WGPEER_HAS_PUBLIC_KEY; + } + break; + case WGPEER_A_PRESHARED_KEY: + if (mnl_attr_get_payload_len(attr) == sizeof(peer->preshared_key)) { + memcpy(peer->preshared_key, mnl_attr_get_payload(attr), sizeof(peer->preshared_key)); + if (!wg_key_is_zero(peer->preshared_key)) + peer->flags |= WGPEER_HAS_PRESHARED_KEY; + } + break; + case WGPEER_A_ENDPOINT: { + struct sockaddr *addr; + + if (mnl_attr_get_payload_len(attr) < sizeof(*addr)) + break; + addr = mnl_attr_get_payload(attr); + if (addr->sa_family == AF_INET && mnl_attr_get_payload_len(attr) == sizeof(peer->endpoint.addr4)) + memcpy(&peer->endpoint.addr4, addr, sizeof(peer->endpoint.addr4)); + else if (addr->sa_family == AF_INET6 && mnl_attr_get_payload_len(attr) == sizeof(peer->endpoint.addr6)) + memcpy(&peer->endpoint.addr6, addr, sizeof(peer->endpoint.addr6)); + break; + } + case WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL: + if (!mnl_attr_validate(attr, MNL_TYPE_U16)) + peer->persistent_keepalive_interval = mnl_attr_get_u16(attr); + break; + case WGPEER_A_LAST_HANDSHAKE_TIME: + if (mnl_attr_get_payload_len(attr) == sizeof(peer->last_handshake_time)) + memcpy(&peer->last_handshake_time, mnl_attr_get_payload(attr), sizeof(peer->last_handshake_time)); + break; + case WGPEER_A_RX_BYTES: + if (!mnl_attr_validate(attr, MNL_TYPE_U64)) + peer->rx_bytes = mnl_attr_get_u64(attr); + break; + case WGPEER_A_TX_BYTES: + if (!mnl_attr_validate(attr, MNL_TYPE_U64)) + peer->tx_bytes = mnl_attr_get_u64(attr); + break; + case WGPEER_A_ALLOWEDIPS: + return mnl_attr_parse_nested(attr, parse_allowedips, peer); + } + + return MNL_CB_OK; +} + +static int parse_peers(const struct nlattr *attr, void *data) +{ + wg_device *device = data; + wg_peer *new_peer = calloc(1, sizeof(wg_peer)); + int ret; + + if (!new_peer) + return MNL_CB_ERROR; + if (!device->first_peer) + device->first_peer = device->last_peer = new_peer; + else { + device->last_peer->next_peer = new_peer; + device->last_peer = new_peer; + } + ret = mnl_attr_parse_nested(attr, parse_peer, new_peer); + if (!ret) + return ret; + if (!(new_peer->flags & WGPEER_HAS_PUBLIC_KEY)) { + errno = ENXIO; + return MNL_CB_ERROR; + } + return MNL_CB_OK; +} + +static int parse_device(const struct nlattr *attr, void *data) +{ + wg_device *device = data; + + switch (mnl_attr_get_type(attr)) { + case WGDEVICE_A_UNSPEC: + break; + case WGDEVICE_A_IFINDEX: + if (!mnl_attr_validate(attr, MNL_TYPE_U32)) + device->ifindex = mnl_attr_get_u32(attr); + break; + case WGDEVICE_A_IFNAME: + if (!mnl_attr_validate(attr, MNL_TYPE_STRING)) { + strncpy(device->name, mnl_attr_get_str(attr), sizeof(device->name) - 1); + device->name[sizeof(device->name) - 1] = '\0'; + } + break; + case WGDEVICE_A_PRIVATE_KEY: + if (mnl_attr_get_payload_len(attr) == sizeof(device->private_key)) { + memcpy(device->private_key, mnl_attr_get_payload(attr), sizeof(device->private_key)); + device->flags |= WGDEVICE_HAS_PRIVATE_KEY; + } + break; + case WGDEVICE_A_PUBLIC_KEY: + if (mnl_attr_get_payload_len(attr) == sizeof(device->public_key)) { + memcpy(device->public_key, mnl_attr_get_payload(attr), sizeof(device->public_key)); + device->flags |= WGDEVICE_HAS_PUBLIC_KEY; + } + break; + case WGDEVICE_A_LISTEN_PORT: + if (!mnl_attr_validate(attr, MNL_TYPE_U16)) + device->listen_port = mnl_attr_get_u16(attr); + break; + case WGDEVICE_A_FWMARK: + if (!mnl_attr_validate(attr, MNL_TYPE_U32)) + device->fwmark = mnl_attr_get_u32(attr); + break; + case WGDEVICE_A_PEERS: + return mnl_attr_parse_nested(attr, parse_peers, device); + } + + return MNL_CB_OK; +} + +static int read_device_cb(const struct nlmsghdr *nlh, void *data) +{ + return mnl_attr_parse(nlh, sizeof(struct genlmsghdr), parse_device, data); +} + +static void coalesce_peers(wg_device *device) +{ + wg_peer *old_next_peer, *peer = device->first_peer; + + while (peer && peer->next_peer) { + if (memcmp(peer->public_key, peer->next_peer->public_key, sizeof(wg_key))) { + peer = peer->next_peer; + continue; + } + if (!peer->first_allowedip) { + peer->first_allowedip = peer->next_peer->first_allowedip; + peer->last_allowedip = peer->next_peer->last_allowedip; + } else { + peer->last_allowedip->next_allowedip = peer->next_peer->first_allowedip; + peer->last_allowedip = peer->next_peer->last_allowedip; + } + old_next_peer = peer->next_peer; + peer->next_peer = old_next_peer->next_peer; + free(old_next_peer); + } +} + +int wg_get_device(wg_device **device, const char *device_name) +{ + int ret = 0; + struct nlmsghdr *nlh; + struct mnlg_socket *nlg; + +try_again: + *device = calloc(1, sizeof(wg_device)); + if (!*device) + return -errno; + + nlg = mnlg_socket_open(WG_GENL_NAME, WG_GENL_VERSION); + if (!nlg) { + wg_free_device(*device); + *device = NULL; + return -errno; + } + + nlh = mnlg_msg_prepare(nlg, WG_CMD_GET_DEVICE, NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP); + mnl_attr_put_strz(nlh, WGDEVICE_A_IFNAME, device_name); + if (mnlg_socket_send(nlg, nlh) < 0) { + ret = -errno; + goto out; + } + errno = 0; + if (mnlg_socket_recv_run(nlg, read_device_cb, *device) < 0) { + ret = errno ? -errno : -EINVAL; + goto out; + } + coalesce_peers(*device); + +out: + if (nlg) + mnlg_socket_close(nlg); + if (ret) { + wg_free_device(*device); + if (ret == -EINTR) + goto try_again; + *device = NULL; + } + errno = -ret; + return ret; +} + +/* first\0second\0third\0forth\0last\0\0 */ +char *wg_list_device_names(void) +{ + struct inflatable_buffer buffer = { .len = MNL_SOCKET_BUFFER_SIZE }; + int ret; + + ret = -ENOMEM; + buffer.buffer = calloc(1, buffer.len); + if (!buffer.buffer) + goto err; + + ret = fetch_device_names(&buffer); +err: + errno = -ret; + if (errno) { + free(buffer.buffer); + return NULL; + } + return buffer.buffer; +} + +int wg_add_device(const char *device_name) +{ + return add_del_iface(device_name, true); +} + +int wg_del_device(const char *device_name) +{ + return add_del_iface(device_name, false); +} + +void wg_free_device(wg_device *dev) +{ + wg_peer *peer, *np; + wg_allowedip *allowedip, *na; + + if (!dev) + return; + for (peer = dev->first_peer, np = peer ? peer->next_peer : NULL; peer; peer = np, np = peer ? peer->next_peer : NULL) { + for (allowedip = peer->first_allowedip, na = allowedip ? allowedip->next_allowedip : NULL; allowedip; allowedip = na, na = allowedip ? allowedip->next_allowedip : NULL) + free(allowedip); + free(peer); + } + free(dev); +} + +static void encode_base64(char dest[static 4], const uint8_t src[static 3]) +{ + const uint8_t input[] = { (src[0] >> 2) & 63, ((src[0] << 4) | (src[1] >> 4)) & 63, ((src[1] << 2) | (src[2] >> 6)) & 63, src[2] & 63 }; + unsigned int i; + + for (i = 0; i < 4; ++i) + dest[i] = input[i] + 'A' + + (((25 - input[i]) >> 8) & 6) + - (((51 - input[i]) >> 8) & 75) + - (((61 - input[i]) >> 8) & 15) + + (((62 - input[i]) >> 8) & 3); + +} + +void wg_key_to_base64(wg_key_b64_string base64, const wg_key key) +{ + unsigned int i; + + for (i = 0; i < 32 / 3; ++i) + encode_base64(&base64[i * 4], &key[i * 3]); + encode_base64(&base64[i * 4], (const uint8_t[]){ key[i * 3 + 0], key[i * 3 + 1], 0 }); + base64[sizeof(wg_key_b64_string) - 2] = '='; + base64[sizeof(wg_key_b64_string) - 1] = '\0'; +} + +static int decode_base64(const char src[static 4]) +{ + int val = 0; + unsigned int i; + + for (i = 0; i < 4; ++i) + val |= (-1 + + ((((('A' - 1) - src[i]) & (src[i] - ('Z' + 1))) >> 8) & (src[i] - 64)) + + ((((('a' - 1) - src[i]) & (src[i] - ('z' + 1))) >> 8) & (src[i] - 70)) + + ((((('0' - 1) - src[i]) & (src[i] - ('9' + 1))) >> 8) & (src[i] + 5)) + + ((((('+' - 1) - src[i]) & (src[i] - ('+' + 1))) >> 8) & 63) + + ((((('/' - 1) - src[i]) & (src[i] - ('/' + 1))) >> 8) & 64) + ) << (18 - 6 * i); + return val; +} + +int wg_key_from_base64(wg_key key, const wg_key_b64_string base64) +{ + unsigned int i; + int val; + volatile uint8_t ret = 0; + + if (strlen(base64) != sizeof(wg_key_b64_string) - 1 || base64[sizeof(wg_key_b64_string) - 2] != '=') { + errno = EINVAL; + goto out; + } + + for (i = 0; i < 32 / 3; ++i) { + val = decode_base64(&base64[i * 4]); + ret |= (uint32_t)val >> 31; + key[i * 3 + 0] = (val >> 16) & 0xff; + key[i * 3 + 1] = (val >> 8) & 0xff; + key[i * 3 + 2] = val & 0xff; + } + val = decode_base64((const char[]){ base64[i * 4 + 0], base64[i * 4 + 1], base64[i * 4 + 2], 'A' }); + ret |= ((uint32_t)val >> 31) | (val & 0xff); + key[i * 3 + 0] = (val >> 16) & 0xff; + key[i * 3 + 1] = (val >> 8) & 0xff; + errno = EINVAL & ~((ret - 1) >> 8); +out: + return -errno; +} + +typedef int64_t fe[16]; + +static __attribute__((noinline)) void memzero_explicit(void *s, size_t count) +{ + memset(s, 0, count); + __asm__ __volatile__("": :"r"(s) :"memory"); +} + +static void carry(fe o) +{ + int i; + + for (i = 0; i < 16; ++i) { + o[(i + 1) % 16] += (i == 15 ? 38 : 1) * (o[i] >> 16); + o[i] &= 0xffff; + } +} + +static void cswap(fe p, fe q, int b) +{ + int i; + int64_t t, c = ~(b - 1); + + for (i = 0; i < 16; ++i) { + t = c & (p[i] ^ q[i]); + p[i] ^= t; + q[i] ^= t; + } + + memzero_explicit(&t, sizeof(t)); + memzero_explicit(&c, sizeof(c)); + memzero_explicit(&b, sizeof(b)); +} + +static void pack(uint8_t *o, const fe n) +{ + int i, j, b; + fe m, t; + + memcpy(t, n, sizeof(t)); + carry(t); + carry(t); + carry(t); + for (j = 0; j < 2; ++j) { + m[0] = t[0] - 0xffed; + for (i = 1; i < 15; ++i) { + m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1); + m[i - 1] &= 0xffff; + } + m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1); + b = (m[15] >> 16) & 1; + m[14] &= 0xffff; + cswap(t, m, 1 - b); + } + for (i = 0; i < 16; ++i) { + o[2 * i] = t[i] & 0xff; + o[2 * i + 1] = t[i] >> 8; + } + + memzero_explicit(m, sizeof(m)); + memzero_explicit(t, sizeof(t)); + memzero_explicit(&b, sizeof(b)); +} + +static void add(fe o, const fe a, const fe b) +{ + int i; + + for (i = 0; i < 16; ++i) + o[i] = a[i] + b[i]; +} + +static void subtract(fe o, const fe a, const fe b) +{ + int i; + + for (i = 0; i < 16; ++i) + o[i] = a[i] - b[i]; +} + +static void multmod(fe o, const fe a, const fe b) +{ + int i, j; + int64_t t[31] = { 0 }; + + for (i = 0; i < 16; ++i) { + for (j = 0; j < 16; ++j) + t[i + j] += a[i] * b[j]; + } + for (i = 0; i < 15; ++i) + t[i] += 38 * t[i + 16]; + memcpy(o, t, sizeof(fe)); + carry(o); + carry(o); + + memzero_explicit(t, sizeof(t)); +} + +static void invert(fe o, const fe i) +{ + fe c; + int a; + + memcpy(c, i, sizeof(c)); + for (a = 253; a >= 0; --a) { + multmod(c, c, c); + if (a != 2 && a != 4) + multmod(c, c, i); + } + memcpy(o, c, sizeof(fe)); + + memzero_explicit(c, sizeof(c)); +} + +static void clamp_key(uint8_t *z) +{ + z[31] = (z[31] & 127) | 64; + z[0] &= 248; +} + +void wg_generate_public_key(wg_key public_key, const wg_key private_key) +{ + int i, r; + uint8_t z[32]; + fe a = { 1 }, b = { 9 }, c = { 0 }, d = { 1 }, e, f; + + memcpy(z, private_key, sizeof(z)); + clamp_key(z); + + for (i = 254; i >= 0; --i) { + r = (z[i >> 3] >> (i & 7)) & 1; + cswap(a, b, r); + cswap(c, d, r); + add(e, a, c); + subtract(a, a, c); + add(c, b, d); + subtract(b, b, d); + multmod(d, e, e); + multmod(f, a, a); + multmod(a, c, a); + multmod(c, b, e); + add(e, a, c); + subtract(a, a, c); + multmod(b, a, a); + subtract(c, d, f); + multmod(a, c, (const fe){ 0xdb41, 1 }); + add(a, a, d); + multmod(c, c, a); + multmod(a, d, f); + multmod(d, b, (const fe){ 9 }); + multmod(b, e, e); + cswap(a, b, r); + cswap(c, d, r); + } + invert(c, c); + multmod(a, a, c); + pack(public_key, a); + + memzero_explicit(&r, sizeof(r)); + memzero_explicit(z, sizeof(z)); + memzero_explicit(a, sizeof(a)); + memzero_explicit(b, sizeof(b)); + memzero_explicit(c, sizeof(c)); + memzero_explicit(d, sizeof(d)); + memzero_explicit(e, sizeof(e)); + memzero_explicit(f, sizeof(f)); +} + +void wg_generate_private_key(wg_key private_key) +{ + wg_generate_preshared_key(private_key); + clamp_key(private_key); +} + +void wg_generate_preshared_key(wg_key preshared_key) +{ + ssize_t ret; + size_t i; + int fd; +#if defined(__OpenBSD__) || (defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12) || (defined(__GLIBC__) && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 25))) + if (!getentropy(preshared_key, sizeof(wg_key))) + return; +#endif +#if defined(__NR_getrandom) && defined(__linux__) + if (syscall(__NR_getrandom, preshared_key, sizeof(wg_key), 0) == sizeof(wg_key)) + return; +#endif + fd = open("/dev/urandom", O_RDONLY); + assert(fd >= 0); + for (i = 0; i < sizeof(wg_key); i += ret) { + ret = read(fd, preshared_key + i, sizeof(wg_key) - i); + assert(ret > 0); + } + close(fd); +} |