diff options
Diffstat (limited to 'app/tools/wg-quick.c')
| -rw-r--r-- | app/tools/wg-quick.c | 649 |
1 files changed, 649 insertions, 0 deletions
diff --git a/app/tools/wg-quick.c b/app/tools/wg-quick.c new file mode 100644 index 00000000..db744d39 --- /dev/null +++ b/app/tools/wg-quick.c @@ -0,0 +1,649 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * + * This is a shell script written in C. It very intentionally still functions like + * a shell script, calling out to external executables such as ip(8). + */ + +#define _GNU_SOURCE +#include <stdlib.h> +#include <stdio.h> +#include <stdbool.h> +#include <string.h> +#include <strings.h> +#include <stdarg.h> +#include <ctype.h> +#include <time.h> +#include <unistd.h> +#include <errno.h> +#include <regex.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/wait.h> +#include <sys/param.h> + +#ifndef WG_CONFIG_SEARCH_PATHS +#define WG_CONFIG_SEARCH_PATHS "/data/misc/wireguard /data/data/com.wireguard.android/files" +#endif + +#define _printf_(x, y) __attribute__((format(printf, x, y))) +#define _cleanup_(x) __attribute__((cleanup(x))) +#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0])) + +static bool is_exiting = false; + +static void *xmalloc(size_t size) +{ + void *ret = malloc(size); + if (ret) + return ret; + perror("Error: malloc"); + exit(errno); +} + +static void *xstrdup(const char *str) +{ + char *ret = strdup(str); + if (ret) + return ret; + perror("Error: strdup"); + exit(errno); +} + +static void xregcomp(regex_t *preg, const char *regex, int cflags) +{ + if (regcomp(preg, regex, cflags)) { + fprintf(stderr, "Error: Regex compilation error\n"); + exit(EBADR); + } +} + +static char *concat(char *first, ...) +{ + va_list args; + size_t len = 0; + char *ret; + + va_start(args, first); + for (char *i = first; i; i = va_arg(args, char *)) + len += strlen(i); + va_end(args); + + ret = xmalloc(len + 1); + ret[0] = '\0'; + + va_start(args, first); + for (char *i = first; i; i = va_arg(args, char *)) + strcat(ret, i); + va_end(args); + + return ret; +} + +static char *concat_and_free(char *orig, const char *delim, const char *new_line) +{ + char *ret; + + if (!orig) + ret = xstrdup(new_line); + else + ret = concat(orig, delim, new_line, NULL); + free(orig); + return ret; +} + +struct command_buffer { + char *line; + size_t len; + FILE *stream; +}; + +static void free_command_buffer(struct command_buffer *c) +{ + if (!c) + return; + if (c->stream) + pclose(c->stream); + free(c->line); +} + +static void freep(void *p) +{ + free(*(void **)p); +} +static void fclosep(FILE **f) +{ + if (*f) + fclose(*f); +} +#define _cleanup_free_ _cleanup_(freep) +#define _cleanup_fclose_ _cleanup_(fclosep) + +#define DEFINE_CMD(name) _cleanup_(free_command_buffer) struct command_buffer name = { 0 }; + +static char *vcmd_ret(struct command_buffer *c, const char *cmd_fmt, va_list args) +{ + _cleanup_free_ char *cmd = NULL; + + if (!c->stream && !cmd_fmt) + return NULL; + if (c->stream && cmd_fmt) + pclose(c->stream); + + if (cmd_fmt) { + if (vasprintf(&cmd, cmd_fmt, args) < 0) { + perror("Error: vasprintf"); + exit(errno); + } + + c->stream = popen(cmd, "r"); + if (!c->stream) { + perror("Error: popen"); + exit(errno); + } + } + errno = 0; + if (getline(&c->line, &c->len, c->stream) < 0) { + if (errno) { + perror("Error: getline"); + exit(errno); + } + return NULL; + } + return c->line; +} + +_printf_(1, 2) static void cmd(const char *cmd_fmt, ...) +{ + _cleanup_free_ char *cmd = NULL; + va_list args; + int ret; + + va_start(args, cmd_fmt); + if (vasprintf(&cmd, cmd_fmt, args) < 0) { + perror("Error: vasprintf"); + exit(errno); + } + va_end(args); + + printf("[#] %s\n", cmd); + ret = system(cmd); + + if (ret < 0) + ret = ESRCH; + else if (ret > 0) + ret = WEXITSTATUS(ret); + + if (ret && !is_exiting) + exit(ret); +} + +_printf_(2, 3) static char *cmd_ret(struct command_buffer *c, const char *cmd_fmt, ...) +{ + va_list args; + char *ret; + + va_start(args, cmd_fmt); + ret = vcmd_ret(c, cmd_fmt, args); + va_end(args); + return ret; +} + +_printf_(1, 2) static void cndc(const char *cmd_fmt, ...) +{ + DEFINE_CMD(c); + int error_code; + char *ret; + va_list args; + _cleanup_free_ char *ndc_fmt = concat("ndc ", cmd_fmt, NULL); + + va_start(args, cmd_fmt); + printf("[#] "); + vprintf(ndc_fmt, args); + printf("\n"); + va_end(args); + + va_start(args, cmd_fmt); + ret = vcmd_ret(&c, ndc_fmt, args); + va_end(args); + + if (!ret) { + fprintf(stderr, "Error: could not call ndc\n"); + exit(ENOSYS); + } + + error_code = atoi(ret); + if (error_code >= 400 && error_code < 600) { + fprintf(stderr, "Error: %s\n", ret); + exit(ENONET); + } +} + +static void auto_su(int argc, char *argv[]) +{ + char *args[argc + 4]; + + if (!getuid()) + return; + + args[0] = "su"; + args[1] = "-p"; + args[2] = "-c"; + memcpy(&args[3], argv, argc * sizeof(*args)); + args[argc + 3] = NULL; + + printf("[$] su -p -c "); + for (int i = 0; i < argc; ++i) + printf("%s%c", argv[i], i == argc - 1 ? '\n' : ' '); + + execvp("su", args); + exit(errno); +} + +static void add_if(const char *iface) +{ + cmd("ip link add %s type wireguard", iface); +} + +static void del_if(const char *iface) +{ + DEFINE_CMD(c); + regex_t reg; + regmatch_t matches[2]; + char *netid = NULL; + _cleanup_free_ char *regex = concat("0xc([0-9a-f]+)/0xcffff lookup ", iface, NULL); + + xregcomp(®, regex, REG_EXTENDED); + + cmd("ip link del %s", iface); + for (char *ret = cmd_ret(&c, "ip rule show"); ret; ret = cmd_ret(&c, NULL)) { + if (!regexec(®, ret, ARRAY_SIZE(matches), matches, 0)) { + ret[matches[1].rm_eo] = '\0'; + netid = &ret[matches[1].rm_so]; + break; + } + } + + if (netid) + cndc("network destroy %lu", strtoul(netid, NULL, 16)); +} + +static void up_if(unsigned int *netid, const char *iface) +{ + srandom(time(NULL) ^ getpid()); /* Not real randomness. */ + + while (*netid < 4096) + *netid = random() & 0xfffe; + + cmd("wg set %s fwmark 0x20000", iface); + cndc("interface setcfg %s up", iface); + cndc("network create %u vpn 1 1", *netid); + cndc("network interface add %u %s", *netid, iface); + cndc("network users add %u 0-99999", *netid); +} + +static void set_dnses(unsigned int netid, const char *dnses) +{ + size_t len = strlen(dnses); + _cleanup_free_ char *mutable = xstrdup(dnses); + _cleanup_free_ char *arglist = xmalloc(len * 4 + 1); + _cleanup_free_ char *arg = xmalloc(len + 4); + + if (!len) + return; + arglist[0] = '\0'; + + for (char *dns = strtok(mutable, ", \t\n"); dns; dns = strtok(NULL, ", \t\n")) { + if (strchr(dns, '\'') || strchr(dns, '\\')) + continue; + snprintf(arg, len + 3, "'%s' ", dns); + strncat(arglist, arg, len * 4 - 1); + } + if (!strlen(arglist)) + return; + cndc("resolver setnetdns %u '' %s", netid, arglist); +} + +static void add_addr(const char *iface, const char *addr) +{ + if (strchr(addr, ':')) { + cndc("interface ipv6 %s enable", iface); + cmd("ip -6 addr add '%s' dev %s", addr, iface); + } else { + _cleanup_free_ char *mut_addr = strdup(addr); + char *slash = strchr(mut_addr, '/'); + unsigned char mask = 32; + + if (slash) { + *slash = '\0'; + mask = atoi(slash + 1); + } + cndc("interface setcfg %s '%s' %u", iface, mut_addr, mask); + } +} + +static void set_addr(const char *iface, const char *addrs) +{ + _cleanup_free_ char *mutable = xstrdup(addrs); + + for (char *addr = strtok(mutable, ", \t\n"); addr; addr = strtok(NULL, ", \t\n")) { + if (strchr(addr, '\'') || strchr(addr, '\\')) + continue; + add_addr(iface, addr); + } +} + +static int get_route_mtu(const char *endpoint) +{ + DEFINE_CMD(c_route); + DEFINE_CMD(c_dev); + regmatch_t matches[2]; + regex_t regex_mtu, regex_dev; + char *route, *mtu, *dev; + + xregcomp(®ex_mtu, "mtu ([0-9]+)", REG_EXTENDED); + xregcomp(®ex_dev, "dev ([^ ]+)", REG_EXTENDED); + + if (strcmp(endpoint, "default")) + route = cmd_ret(&c_route, "ip -o route get %s", endpoint); + else + route = cmd_ret(&c_route, "ip -o route show %s", endpoint); + if (!route) + return -1; + + if (!regexec(®ex_mtu, route, ARRAY_SIZE(matches), matches, 0)) { + route[matches[1].rm_eo] = '\0'; + mtu = &route[matches[1].rm_so]; + } else if (!regexec(®ex_dev, route, ARRAY_SIZE(matches), matches, 0)) { + route[matches[1].rm_eo] = '\0'; + dev = &route[matches[1].rm_so]; + route = cmd_ret(&c_dev, "ip -o link show dev %s", dev); + if (!route) + return -1; + if (regexec(®ex_mtu, route, ARRAY_SIZE(matches), matches, 0)) + return -1; + route[matches[1].rm_eo] = '\0'; + mtu = &route[matches[1].rm_so]; + } else + return -1; + return atoi(mtu); +} + +static void set_mtu(const char *iface, unsigned int mtu) +{ + DEFINE_CMD(c_endpoints); + regex_t regex_endpoint; + regmatch_t matches[2]; + int endpoint_mtu, next_mtu; + + if (mtu) { + cndc("interface setmtu %s %u", iface, mtu); + return; + } + + xregcomp(®ex_endpoint, "^\\[?([a-z0-9:.]+)\\]?:[0-9]+$", REG_EXTENDED); + + endpoint_mtu = get_route_mtu("default"); + if (endpoint_mtu == -1) + endpoint_mtu = 1500; + + for (char *endpoint = cmd_ret(&c_endpoints, "wg show %s endpoints", iface); endpoint; endpoint = cmd_ret(&c_endpoints, NULL)) { + if (regexec(®ex_endpoint, endpoint, ARRAY_SIZE(matches), matches, 0)) + continue; + endpoint[matches[1].rm_eo] = '\0'; + endpoint = &endpoint[matches[1].rm_so]; + + next_mtu = get_route_mtu(endpoint); + if (next_mtu > 0 && next_mtu < endpoint_mtu) + endpoint_mtu = next_mtu; + } + + cndc("interface setmtu %s %d", iface, endpoint_mtu - 80); +} + +static void add_route(const char *iface, unsigned int netid, const char *route) +{ + cndc("network route add %u %s %s", netid, iface, route); +} + +static void set_routes(const char *iface, unsigned int netid) +{ + DEFINE_CMD(c); + + for (char *allowedips = cmd_ret(&c, "wg show %s allowed-ips", iface); allowedips; allowedips = cmd_ret(&c, NULL)) { + char *start = strchr(allowedips, '\t'); + + if (!start) + continue; + ++start; + for (char *allowedip = strtok(start, " \n"); allowedip; allowedip = strtok(NULL, " \n")) + add_route(iface, netid, allowedip); + } +} + +static void set_config(const char *iface, const char *config) +{ + FILE *config_writer; + _cleanup_free_ char *cmd = concat("wg setconf ", iface, " /proc/self/fd/0", NULL); + + printf("[#] %s\n", cmd); + + config_writer = popen(cmd, "w"); + if (!config_writer) { + perror("Error: popen"); + exit(errno); + } + if (fputs(config, config_writer) < 0) { + perror("Error: fputs"); + exit(errno); + } + pclose(config_writer); +} + +static void print_search_paths(FILE *file, const char *prefix) +{ + _cleanup_free_ char *paths = strdup(WG_CONFIG_SEARCH_PATHS); + + for (char *path = strtok(paths, " "); path; path = strtok(NULL, " ")) + fprintf(file, "%s%s\n", prefix, path); +} + +static void cmd_usage(const char *program) +{ + printf( "Usage: %s [ up | down ] [ CONFIG_FILE | INTERFACE ]\n" + "\n" + " CONFIG_FILE is a configuration file, whose filename is the interface name\n" + " followed by `.conf'. Otherwise, INTERFACE is an interface name, with\n" + " configuration found at:\n\n", program); + print_search_paths(stdout, " - "); + printf( "\n It is to be readable by wg(8)'s `setconf' sub-command, with the exception\n" + " of the following additions to the [Interface] section, which are handled by\n" + " this program:\n\n" + " - Address: may be specified one or more times and contains one or more\n" + " IP addresses (with an optional CIDR mask) to be set for the interface.\n" + " - MTU: an optional MTU for the interface; if unspecified, auto-calculated.\n" + " - DNS: an optional DNS server to use while the device is up.\n\n" + " See wg-quick(8) for more info and examples.\n"); +} + +static char *cleanup_iface = NULL; + +static void cmd_up_cleanup(void) +{ + is_exiting = true; + if (cleanup_iface) + del_if(cleanup_iface); + free(cleanup_iface); +} + +static void cmd_up(const char *iface, const char *config, unsigned int mtu, const char *addrs, const char *dnses) +{ + DEFINE_CMD(c); + unsigned int netid = 0; + + if (cmd_ret(&c, "ip link show dev %s 2>/dev/null", iface)) { + fprintf(stderr, "Error: %s already exists\n", iface); + exit(EEXIST); + } + + cleanup_iface = xstrdup(iface); + atexit(cmd_up_cleanup); + + add_if(iface); + set_config(iface, config); + set_mtu(iface, mtu); + set_addr(iface, addrs); + up_if(&netid, iface); + set_dnses(netid, dnses); + set_routes(iface, netid); + + free(cleanup_iface); + cleanup_iface = NULL; + exit(EXIT_SUCCESS); +} + +static void cmd_down(const char *iface) +{ + DEFINE_CMD(c); + bool found = false; + + char *ifaces = cmd_ret(&c, "wg show interfaces"); + if (ifaces) { + for (char *eiface = strtok(ifaces, " \n"); eiface; eiface = strtok(NULL, " \n")) { + if (!strcmp(iface, eiface)) { + found = true; + break; + } + } + } + if (!found) { + fprintf(stderr, "Error: %s is not a WireGuard interface\n", iface); + exit(EMEDIUMTYPE); + } + + del_if(iface); + exit(EXIT_SUCCESS); +} + +static void parse_options(char **iface, char **config, unsigned int *mtu, char **addrs, char **dnses, const char *arg) +{ + _cleanup_fclose_ FILE *file = NULL; + _cleanup_free_ char *line = NULL; + _cleanup_free_ char *filename = NULL; + _cleanup_free_ char *paths = strdup(WG_CONFIG_SEARCH_PATHS); + regex_t regex_iface, regex_conf; + regmatch_t matches[2]; + struct stat sbuf; + size_t n = 0; + bool in_interface_section = false; + + *iface = *config = *addrs = *dnses = NULL; + *mtu = 0; + + xregcomp(®ex_iface, "^[a-zA-Z0-9_=+.-]{1,16}$", REG_EXTENDED | REG_NOSUB); + xregcomp(®ex_conf, "/?([a-zA-Z0-9_=+.-]{1,16})\\.conf$", REG_EXTENDED); + + if (!regexec(®ex_iface, arg, 0, NULL, 0)) { + for (char *path = strtok(paths, " "); path; path = strtok(NULL, " ")) { + free(filename); + if (asprintf(&filename, "%s/%s.conf", path, arg) < 0) { + perror("Error: asprintf"); + exit(errno); + } + file = fopen(filename, "r"); + if (file) + break; + } + if (!file) { + fprintf(stderr, "Error: Unable to find configuration file for `%s' in:\n", arg); + print_search_paths(stderr, "- "); + exit(errno); + } + } else { + filename = xstrdup(arg); + file = fopen(filename, "r"); + if (!file) { + fprintf(stderr, "Error: Unable to find configuration file at `%s'\n", filename); + exit(errno); + } + } + + if (regexec(®ex_conf, filename, ARRAY_SIZE(matches), matches, 0)) { + fprintf(stderr, "Error: The config file must be a valid interface name, followed by .conf\n"); + exit(EINVAL); + } + + if (fstat(fileno(file), &sbuf) < 0) { + perror("Error: fstat"); + exit(errno); + } + if (sbuf.st_mode & 0007) + fprintf(stderr, "Warning: `%s' is world accessible\n", filename); + + filename[matches[1].rm_eo] = 0; + *iface = xstrdup(&filename[matches[1].rm_so]); + + while (getline(&line, &n, file) >= 0) { + size_t len = strlen(line), j = 0; + _cleanup_free_ char *clean = xmalloc(len + 1); + + for (size_t i = 0; i < len; ++i) { + if (!isspace(line[i])) + clean[j++] = line[i]; + } + clean[j] = '\0'; + + if (clean[0] == '[') + in_interface_section = false; + if (!strcasecmp(clean, "[Interface]")) + in_interface_section = true; + if (in_interface_section) { + if (!strncasecmp(clean, "Address=", 8) && j > 8) { + *addrs = concat_and_free(*addrs, ",", clean + 8); + continue; + } else if (!strncasecmp(clean, "DNS=", 4) && j > 4) { + *dnses = concat_and_free(*dnses, ",", clean + 4); + continue; + } else if (!strncasecmp(clean, "MTU=", 4) && j > 4) { + *mtu = atoi(clean + 4); + continue; + } + } + *config = concat_and_free(*config, "", line); + } + + if (!*iface) + *iface = xstrdup(""); + if (!*config) + *config = xstrdup(""); + if (!*addrs) + *addrs = xstrdup(""); + if (!*dnses) + *dnses = xstrdup(""); +} + +int main(int argc, char *argv[]) +{ + _cleanup_free_ char *iface = NULL; + _cleanup_free_ char *config = NULL; + _cleanup_free_ char *addrs = NULL; + _cleanup_free_ char *dnses = NULL; + unsigned int mtu; + + if (argc == 2 && (!strcmp(argv[1], "help") || !strcmp(argv[1], "--help") || !strcmp(argv[1], "-h"))) + cmd_usage(argv[0]); + else if (argc == 3 && !strcmp(argv[1], "up")) { + auto_su(argc, argv); + parse_options(&iface, &config, &mtu, &addrs, &dnses, argv[2]); + cmd_up(iface, config, mtu, addrs, dnses); + } else if (argc == 3 && !strcmp(argv[1], "down")) { + auto_su(argc, argv); + parse_options(&iface, &config, &mtu, &addrs, &dnses, argv[2]); + cmd_down(iface); + } else { + cmd_usage(argv[0]); + return 1; + } + return 0; +} |