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>
34 /* Necessary for GnuTLS when used with threads. */
36 GCRY_THREAD_OPTION_PTHREAD_IMPL;
39 /* Size of ringbuffer. */
40 #define RINGBUFFER_SIZE 10
42 /* Bit size of Diffie-Hellman key exchange parameters. */
46 /* For gnutls_*() functions. */
47 #define GNUTLS_ERROR_EXIT(error, message) \
48 if (error != GNUTLS_E_SUCCESS) { \
49 fprintf(stderr, "%s: %s\n", message, gnutls_strerror(error)); \
54 /* Server should shut down. Set by SIGINT handler. */
55 static volatile int done = 0;
57 /* Number of threads. */
58 static size_t thread_count;
60 /* Synchronized ring buffer storing accept()ed client sockets. */
61 static int ringbuffer[RINGBUFFER_SIZE];
62 static int ringbuffer_read;
63 static int ringbuffer_write;
64 static SEM *ringbuffer_full; /* At least one element in the buffer? */
65 static SEM *ringbuffer_free; /* Space for another element in the buffer? */
66 static SEM *ringbuffer_lock; /* Read lock. */
70 static void sigint_handler(int signal);
73 static void parse_arguments(int argc, char **argv);
74 static void print_usage(const char *argv);
76 static void initialize_gnutls(void);
77 static void deinitialize_gnutls(void);
79 static void *worker_thread(void *unused);
82 int main(int argc, char **argv) {
84 int client_socket, server_socket;
86 struct sockaddr_in server_in;
88 struct sockaddr_in6 server_in;
94 struct sigaction action;
96 parse_arguments(argc, argv);
98 port = atoi(argv[argc - 1]);
99 if (port <= 0 || port > 0xffff ) {
100 fprintf(stderr, "invalid port: '%s'\n", argv[argc - 1]);
104 sigemptyset(&action.sa_mask);
107 /* Setup our SIGINT signal handler which allows a "normal" termination of
108 * the server in DEBUG mode. */
109 action.sa_handler = sigint_handler;
110 sigaction(SIGINT, &action, NULL);
112 /* Ignore SIGPIPEs. */
113 action.sa_handler = SIG_IGN;
114 sigaction(SIGPIPE, &action, NULL);
116 /* Initialize ring buffer. */
118 ringbuffer_write = 0;
119 ringbuffer_full = sem_init(0);
120 ringbuffer_free = sem_init(RINGBUFFER_SIZE);
121 ringbuffer_lock = sem_init(1);
122 if (NULL == ringbuffer_full
123 || NULL == ringbuffer_free
124 || NULL == ringbuffer_lock) {
125 perror("sem_init()");
131 /* Spawn worker threads to handle requests. */
132 threads = malloc(thread_count * sizeof(*threads));
133 if (threads == NULL) {
134 perror("thread malloc failed");
137 for (i = 0; i < thread_count; i++) {
138 errno = pthread_create(threads + i, NULL, &worker_thread, NULL);
140 perror("failed to create worker thread");
146 server_socket = socket(PF_INET, SOCK_STREAM, 0);
148 server_socket = socket(PF_INET6, SOCK_STREAM, 0);
150 if (server_socket == -1) {
155 /* Fast rebinding for debug mode, could cause invalid packets. */
156 if (global_log_level >= LOG_DEBUG_LEVEL) {
157 int socket_option = 1;
158 setsockopt(server_socket, SOL_SOCKET, SO_REUSEADDR,
159 &socket_option, sizeof(socket_option));
162 /* Bind to the listen socket. */
163 memset(&server_in, 0, sizeof(server_in));
165 server_in.sin_family = AF_INET; /* IPv4 only */
166 server_in.sin_addr.s_addr = htonl(INADDR_ANY); /* bind to any address */
167 server_in.sin_port = htons((uint16_t)port); /* port to bind to */
169 server_in.sin6_family = AF_INET6; /* IPv6 (and IPv4) */
170 server_in.sin6_addr = in6addr_any; /* bind to any address */
171 server_in.sin6_port = htons((uint16_t)port); /* port to bind to */
173 if (bind(server_socket, (struct sockaddr *)&server_in,
174 sizeof(server_in)) == -1) {
178 /* And accept connections. */
179 if (listen(server_socket, 5) == -1) {
184 if (global_log_level >= LOG_DEBUG_LEVEL) {
185 printf("tlsproxy %s\n", VERSION);
186 printf("Listening for connections on port %d.\n", port);
188 if (global_proxy_host != NULL && global_proxy_port != NULL) {
189 printf("Using proxy: %s:%s.\n", global_proxy_host,
195 /* Accept new connection. */
196 client_socket = accept(server_socket, NULL, NULL);
197 if (client_socket == -1) {
202 /* No lock necessary, we only have one producer! */
204 ringbuffer[ringbuffer_write] = client_socket;
205 ringbuffer_write = (ringbuffer_write + 1) % RINGBUFFER_SIZE;
209 close(server_socket);
211 /* Poison all threads and shut them down. */
212 for (i = 0; i < thread_count; i++) {
214 ringbuffer[ringbuffer_write] = -1; /* poison */
215 ringbuffer_write = (ringbuffer_write + 1) % RINGBUFFER_SIZE;
218 for (i = 0; i < thread_count; i++) {
219 errno = pthread_join(threads[i], NULL);
221 perror("pthread_join()");
225 sem_del(ringbuffer_full);
226 sem_del(ringbuffer_free);
227 sem_del(ringbuffer_lock);
231 deinitialize_gnutls();
233 free(global_proxy_host);
234 free(global_proxy_port);
240 static void sigint_handler(int signal_number) {
247 static void parse_arguments(int argc, char **argv) {
250 /* Default values. */
253 global_log_level = LOG_DEBUG_LEVEL;
255 global_log_level = LOG_WARNING_LEVEL;
257 global_passthrough_unknown = 0;
259 while ((option = getopt(argc, argv, "d:p:t:uh?")) != -1) {
262 global_log_level = atoi(optarg);
263 if (global_log_level < 0) {
264 fprintf(stderr, "-d positive number required: '%s'\n",
273 /* -p must have the format host:port. */
274 if ((position = strchr(optarg, ':')) == NULL
275 || optarg == position
276 || strlen(position + 1) == 0
277 || atoi(position + 1) <= 0
278 || atoi(position + 1) > 0xffff) {
279 fprintf(stderr, "invalid -p: '%s', format host:port\n",
284 global_proxy_host = malloc((size_t)(position - optarg) + 1);
285 if (global_proxy_host == NULL) {
289 memcpy(global_proxy_host, optarg, (size_t)(position - optarg));
290 global_proxy_host[position - optarg] = '\0';
292 global_proxy_port = malloc(strlen(position + 1) + 1);
293 if (global_proxy_port == NULL) {
297 strcpy(global_proxy_port, position + 1);
302 if (atoi(optarg) <= 0) {
303 fprintf(stderr, "-t positive number required: '%s'\n",
307 thread_count = (size_t)atoi(optarg);
311 global_passthrough_unknown = 1;
316 print_usage(argv[0]);
321 if (optind >= argc) {
322 fprintf(stderr, "port missing\n");
326 static void print_usage(const char *argv) {
327 fprintf(stderr, "tlsproxy %s, a certificate checking TLS proxy\n",
329 fprintf(stderr, "Usage: %s [-d level] [-p host:port] [-t count] [-u] port\n",
331 fprintf(stderr, "\n");
332 fprintf(stderr, "-d debug level: 0=errors only, 2=debug [default: 1]\n");
333 fprintf(stderr, "-p proxy hostname and port\n");
334 fprintf(stderr, "-t number of threads [default: 10]\n");
335 fprintf(stderr, "-u passthrough connection if no certificate is stored \
336 [default: error]\n");
337 fprintf(stderr, " WARNING: might be a security problem!\n");
340 static void initialize_gnutls(void) {
344 /* Thread safe setup. Must be called before gnutls_global_init(). */
345 error = gcry_control(GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
347 fprintf(stderr, "gcry_control(): %s/%s\n", gcry_strsource(error),
348 gcry_strerror(error));
351 /* Prevent usage of blocking /dev/random. */
352 error = gcry_control(GCRYCTL_ENABLE_QUICK_RANDOM, 0);
354 fprintf(stderr, "gcry_control(): %s/%s\n", gcry_strsource(error),
355 gcry_strerror(error));
359 /* Initialize GnuTLS. */
360 result = gnutls_global_init();
361 GNUTLS_ERROR_EXIT(result, "gnutls_global_init()");
363 /* Setup GnuTLS cipher suites. */
364 result = gnutls_priority_init(&global_tls_priority_cache, "NORMAL", NULL);
365 GNUTLS_ERROR_EXIT(result, "gnutls_priority_init()");
367 /* Generate Diffie-Hellman parameters. */
368 result = gnutls_dh_params_init(&global_tls_dh_params);
369 GNUTLS_ERROR_EXIT(result, "gnutls_dh_params_init()");
370 result = gnutls_dh_params_generate2(global_tls_dh_params, DH_SIZE);
371 GNUTLS_ERROR_EXIT(result, "gnutls_dh_params_generate2()");
373 static void deinitialize_gnutls(void) {
374 gnutls_dh_params_deinit(global_tls_dh_params);
375 gnutls_priority_deinit(global_tls_priority_cache);
377 gnutls_global_deinit();
380 static void *worker_thread(void *unused) {
386 /* Get next element from ring buffer. */
389 client_socket = ringbuffer[ringbuffer_read];
390 ringbuffer_read = (ringbuffer_read + 1) % RINGBUFFER_SIZE;
394 /* Negative value indicates we should shut down our thread. */
395 if (client_socket < 0) {
399 handle_connection(client_socket);