mirror of
https://github.com/yarrick/iodine.git
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188 lines
3.6 KiB
C
188 lines
3.6 KiB
C
/*
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* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>, Erik Ekman <yarrick@kryo.se>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <err.h>
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#include <pwd.h>
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#include <arpa/inet.h>
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#include <zlib.h>
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#include "tun.h"
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#include "dns.h"
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#include "dnsd.h"
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#ifndef MAX
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#define MAX(a,b) ((a)>(b)?(a):(b))
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#endif
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int running = 1;
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static void
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sigint(int sig) {
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running = 0;
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}
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static int
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tunnel(int tun_fd, int dns_fd)
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{
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int i;
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int read;
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fd_set fds;
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struct timeval tv;
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struct tun_frame *frame;
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long buflen;
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char buf[64*1024];
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frame = malloc(64*1024);
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while (running) {
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if (dnsd_hasack()) {
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tv.tv_sec = 0;
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tv.tv_usec = 50000;
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} else {
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tv.tv_sec = 1;
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tv.tv_usec = 0;
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}
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FD_ZERO(&fds);
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if(!dnsd_haspacket())
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FD_SET(tun_fd, &fds);
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FD_SET(dns_fd, &fds);
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i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv);
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if(i < 0) {
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if (running)
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warn("select");
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return 1;
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}
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if (i==0) {
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if (dnsd_hasack())
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dnsd_forceack(dns_fd);
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} else {
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if(FD_ISSET(tun_fd, &fds)) {
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read = read_tun(tun_fd, frame, 64*1024);
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if(read > 0) {
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buflen = sizeof(buf);
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compress2(buf, &buflen, frame->data, read - 4, 9);
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dnsd_queuepacket(buf, buflen);
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}
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}
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if(FD_ISSET(dns_fd, &fds)) {
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read = dnsd_read(dns_fd, buf, 64*1024-4);
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if(read > 0) {
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buflen = 64*1024-4;
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uncompress(frame->data, &buflen, buf, read);
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frame->flags = htons(0x0000);
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#ifdef LINUX
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frame->proto = htons(0x0800); // Linux wants ETH_P_IP
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#else
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frame->proto = htons(0x0002); // BSD wants AF_INET as long word
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#endif
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write_tun(tun_fd, frame, buflen + 4);
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}
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}
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}
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}
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free(frame);
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return 0;
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}
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extern char *__progname;
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static void
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usage() {
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printf("Usage: %s [-u user] topdomain\n", __progname);
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exit(2);
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}
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int
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main(int argc, char **argv)
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{
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int tun_fd;
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int dnsd_fd;
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int choice;
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char *username;
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struct passwd *pw;
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username = NULL;
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if (geteuid() != 0) {
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printf("Run as root and you'll be happy.\n");
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usage();
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}
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while ((choice = getopt(argc, argv, "u:")) != -1) {
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switch(choice) {
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case 'u':
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username = optarg;
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break;
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default:
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usage();
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break;
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}
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}
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argc -= optind;
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argv += optind;
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if (argc != 1) {
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usage();
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}
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if (username) {
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pw = getpwnam(username);
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if (!pw) {
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printf("User %s does not exist!\n", username);
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usage();
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}
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}
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tun_fd = open_tun();
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dnsd_fd = open_dnsd(argv[0]);
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printf("Listening to dns for domain %s\n", argv[0]);
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signal(SIGINT, sigint);
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if (username) {
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if (setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0) {
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printf("Could not switch to user %s!\n", username);
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usage();
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}
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printf("Now running as user %s\n", username);
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}
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tunnel(tun_fd, dnsd_fd);
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printf("Closing tunnel\n");
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close_dnsd(dnsd_fd);
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close_tun(tun_fd);
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return 0;
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}
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