2 * tlsproxy is a TLS proxy for HTTPS which intercepts the connections and
3 * ensures the server certificate doesn't change. Normally this isn't detected
4 * if a trusted CA for the new server certificate is installed.
6 * Copyright (C) 2011-2013 Simon Ruderich
8 * This program is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>.
24 #include "connection.h"
26 #include <arpa/inet.h>
30 #include <sys/socket.h>
31 #include <sys/types.h>
37 GCRY_THREAD_OPTION_PTHREAD_IMPL;
40 /* Size of ringbuffer. */
41 #define RINGBUFFER_SIZE 10
43 /* Bit size of Diffie-Hellman key exchange parameters. */
47 /* For gnutls_*() functions. */
48 #define GNUTLS_ERROR_EXIT(error, message) \
49 if (error != GNUTLS_E_SUCCESS) { \
50 fprintf(stderr, "%s: %s\n", message, gnutls_strerror(error)); \
55 /* Server should shut down. Set by SIGINT handler. */
56 static volatile int done = 0;
58 /* Number of threads. */
59 static size_t thread_count;
61 /* Synchronized ring buffer storing accept()ed client sockets. */
62 static int ringbuffer[RINGBUFFER_SIZE];
63 static int ringbuffer_read;
64 static int ringbuffer_write;
65 static SEM *ringbuffer_full; /* At least one element in the buffer? */
66 static SEM *ringbuffer_free; /* Space for another element in the buffer? */
67 static SEM *ringbuffer_lock; /* Read lock. */
71 static void sigint_handler(int signal);
74 static void parse_arguments(int argc, char **argv);
75 static void print_usage(const char *argv);
77 static void initialize_gnutls(void);
78 static void deinitialize_gnutls(void);
80 static void worker_thread(void);
83 int main(int argc, char **argv) {
85 int client_socket, server_socket;
87 struct sockaddr_in server_in;
89 struct sockaddr_in6 server_in;
95 struct sigaction action;
97 parse_arguments(argc, argv);
99 port = atoi(argv[argc - 1]);
100 if (port <= 0 || port > 0xffff ) {
101 print_usage(argv[0]);
102 fprintf(stderr, "\ninvalid port: '%s'\n", argv[argc - 1]);
106 sigemptyset(&action.sa_mask);
109 /* Setup our SIGINT signal handler which allows a "normal" termination of
110 * the server in DEBUG mode. */
111 action.sa_handler = sigint_handler;
112 sigaction(SIGINT, &action, NULL);
114 /* Ignore SIGPIPEs. */
115 action.sa_handler = SIG_IGN;
116 sigaction(SIGPIPE, &action, NULL);
118 /* Initialize ring buffer. */
120 ringbuffer_write = 0;
121 ringbuffer_full = sem_init(0);
122 ringbuffer_free = sem_init(RINGBUFFER_SIZE);
123 ringbuffer_lock = sem_init(1);
124 if (NULL == ringbuffer_full
125 || NULL == ringbuffer_free
126 || NULL == ringbuffer_lock) {
127 perror("sem_init()");
133 /* Spawn worker threads to handle requests. */
134 threads = malloc(thread_count * sizeof(*threads));
135 if (threads == NULL) {
136 perror("thread malloc failed");
139 for (i = 0; i < thread_count; i++) {
143 result = pthread_create(&thread, NULL,
144 (void * (*)(void *))&worker_thread,
147 fprintf(stderr, "failed to create worker thread: %s\n",
156 server_socket = socket(PF_INET, SOCK_STREAM, 0);
158 server_socket = socket(PF_INET6, SOCK_STREAM, 0);
160 if (server_socket == -1) {
165 /* Fast rebinding for debug mode, could cause invalid packets. */
166 if (global_log_level >= LOG_DEBUG_LEVEL) {
167 int socket_option = 1;
168 setsockopt(server_socket, SOL_SOCKET, SO_REUSEADDR,
169 &socket_option, sizeof(socket_option));
172 /* Bind to the listen socket. */
173 memset(&server_in, 0, sizeof(server_in));
175 server_in.sin_family = AF_INET; /* IPv4 only */
176 server_in.sin_addr.s_addr = htonl(INADDR_ANY); /* bind to any address */
177 server_in.sin_port = htons((uint16_t)port); /* port to bind to */
179 server_in.sin6_family = AF_INET6; /* IPv6 (and IPv4) */
180 server_in.sin6_addr = in6addr_any; /* bind to any address */
181 server_in.sin6_port = htons((uint16_t)port); /* port to bind to */
183 if (bind(server_socket, (struct sockaddr *)&server_in,
184 sizeof(server_in)) == -1) {
188 /* And accept connections. */
189 if (listen(server_socket, 5) == -1) {
194 if (global_log_level >= LOG_DEBUG_LEVEL) {
195 printf("tlsproxy %s\n", VERSION);
196 printf("Listening for connections on port %d.\n", port);
198 if (global_proxy_host != NULL && global_proxy_port != NULL) {
199 printf("Using proxy: %s:%s.\n", global_proxy_host,
205 /* Accept new connection. */
206 client_socket = accept(server_socket, NULL, NULL);
207 if (client_socket == -1) {
212 /* No lock necessary, we only have one producer! */
214 ringbuffer[ringbuffer_write] = client_socket;
215 ringbuffer_write = (ringbuffer_write + 1) % RINGBUFFER_SIZE;
219 close(server_socket);
221 /* Poison all threads and shut them down. */
222 for (i = 0; i < thread_count; i++) {
224 ringbuffer[ringbuffer_write] = -1; /* poison */
225 ringbuffer_write = (ringbuffer_write + 1) % RINGBUFFER_SIZE;
228 for (i = 0; i < thread_count; i++) {
229 errno = pthread_join(threads[i], NULL);
231 perror("pthread_join()");
235 free(ringbuffer_full);
236 free(ringbuffer_free);
237 free(ringbuffer_lock);
241 deinitialize_gnutls();
243 free(global_proxy_host);
244 free(global_proxy_port);
250 static void sigint_handler(int signal_number) {
257 static void parse_arguments(int argc, char **argv) {
260 /* Default values. */
263 global_log_level = LOG_DEBUG_LEVEL;
265 global_log_level = LOG_WARNING_LEVEL;
267 global_passthrough_unknown = 0;
269 while ((option = getopt(argc, argv, "d:p:t:uh?")) != -1) {
272 if (atoi(optarg) < 0) {
273 print_usage(argv[0]);
274 fprintf(stderr, "\n-d positive number required: '%s'\n",
278 global_log_level = atoi(optarg);
284 /* -p must have the format host:port. */
285 if ((position = strchr(optarg, ':')) == NULL
286 || optarg == position
287 || strlen(position + 1) == 0
288 || atoi(position + 1) <= 0
289 || atoi(position + 1) > 0xffff) {
290 print_usage(argv[0]);
291 fprintf(stderr, "\ninvalid -p: '%s', format host:port\n",
296 global_proxy_host = malloc((size_t)(position - optarg) + 1);
297 if (global_proxy_host == NULL) {
301 memcpy(global_proxy_host, optarg, (size_t)(position - optarg));
302 global_proxy_host[position - optarg] = '\0';
304 global_proxy_port = malloc(strlen(position + 1) + 1);
305 if (global_proxy_port == NULL) {
309 strcpy(global_proxy_port, position + 1);
314 if (atoi(optarg) <= 0) {
315 print_usage(argv[0]);
316 fprintf(stderr, "\n-t positive number required: '%s'\n",
320 thread_count = (size_t)atoi(optarg);
324 global_passthrough_unknown = 1;
329 print_usage(argv[0]);
334 if (optind >= argc) {
335 print_usage(argv[0]);
336 fprintf(stderr, "\nport missing\n");
340 static void print_usage(const char *argv) {
341 fprintf(stderr, "tlsproxy %s, a certificate checking TLS proxy\n",
343 fprintf(stderr, "Usage: %s [-d level] [-p host:port] [-t count] [-u] port\n",
345 fprintf(stderr, "\n");
346 fprintf(stderr, "-d debug level: 0=errors only, 2=debug [default: 1]\n");
347 fprintf(stderr, "-p proxy hostname and port\n");
348 fprintf(stderr, "-t number of threads [default: 10]\n");
349 fprintf(stderr, "-u passthrough connection if no certificate is stored \
350 [default: error]\n");
351 fprintf(stderr, " WARNING: might be a security problem!\n");
354 static void initialize_gnutls(void) {
356 gcry_error_t error = 0;
358 /* Thread safe setup. Must be called before gnutls_global_init(). */
359 error = gcry_control(GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
361 fprintf(stderr, "gcry_control(): %s/%s\n", gcry_strsource(error),
362 gcry_strerror(error));
365 /* Prevent usage of blocking /dev/random. */
366 error = gcry_control(GCRYCTL_ENABLE_QUICK_RANDOM, 0);
368 fprintf(stderr, "gcry_control(): %s/%s\n", gcry_strsource(error),
369 gcry_strerror(error));
373 /* Initialize GnuTLS. */
374 result = gnutls_global_init();
375 GNUTLS_ERROR_EXIT(result, "gnutls_global_init()");
377 /* Setup GnuTLS cipher suites. */
378 result = gnutls_priority_init(&global_tls_priority_cache, "NORMAL", NULL);
379 GNUTLS_ERROR_EXIT(result, "gnutls_priority_init()");
381 /* Generate Diffie-Hellman parameters. */
382 result = gnutls_dh_params_init(&global_tls_dh_params);
383 GNUTLS_ERROR_EXIT(result, "gnutls_dh_params_init()");
384 result = gnutls_dh_params_generate2(global_tls_dh_params, DH_SIZE);
385 GNUTLS_ERROR_EXIT(result, "gnutls_dh_params_generate2()");
387 static void deinitialize_gnutls(void) {
388 gnutls_dh_params_deinit(global_tls_dh_params);
389 gnutls_priority_deinit(global_tls_priority_cache);
391 gnutls_global_deinit();
394 static void worker_thread(void) {
398 /* Get next element from ring buffer. */
401 client_socket = ringbuffer[ringbuffer_read];
402 ringbuffer_read = (ringbuffer_read + 1) % RINGBUFFER_SIZE;
406 /* Negative value indicates we should shut down our thread. */
407 if (client_socket < 0) {
411 handle_connection(client_socket);