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>
32 #include <sys/types.h>
35 /* Necessary for GnuTLS when used with threads. */
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);
76 static char *slurp_file(const char *path);
78 static void initialize_gnutls(void);
79 static void deinitialize_gnutls(void);
81 static void *worker_thread(void *unused);
84 int main(int argc, char **argv) {
86 int client_socket, server_socket;
88 struct sockaddr_in server_in;
90 struct sockaddr_in6 server_in;
96 struct sigaction action;
98 /* Required in a few places. */
99 ct_assert(sizeof(size_t) >= sizeof(int));
100 ct_assert(sizeof(size_t) >= sizeof(ssize_t));
102 parse_arguments(argc, argv);
104 port = atoi(argv[argc - 1]);
105 if (port <= 0 || port > 0xffff ) {
106 fprintf(stderr, "invalid port: '%s'\n", argv[argc - 1]);
110 memset(&action, 0, sizeof(action));
111 sigemptyset(&action.sa_mask);
113 /* Setup our SIGINT signal handler which allows a "normal" termination of
114 * the server in DEBUG mode. */
115 action.sa_handler = sigint_handler;
116 sigaction(SIGINT, &action, NULL);
118 /* Ignore SIGPIPEs. */
119 action.sa_handler = SIG_IGN;
120 sigaction(SIGPIPE, &action, NULL);
122 /* Initialize ring buffer. */
124 ringbuffer_write = 0;
125 ringbuffer_full = sem_init(0);
126 ringbuffer_free = sem_init(RINGBUFFER_SIZE);
127 ringbuffer_lock = sem_init(1);
128 if (NULL == ringbuffer_full
129 || NULL == ringbuffer_free
130 || NULL == ringbuffer_lock) {
131 perror("sem_init()");
137 /* Spawn worker threads to handle requests. */
138 threads = malloc(thread_count * sizeof(*threads));
139 if (threads == NULL) {
140 perror("thread malloc failed");
143 for (i = 0; i < thread_count; i++) {
144 errno = pthread_create(threads + i, NULL, &worker_thread, NULL);
146 perror("failed to create worker thread");
152 server_socket = socket(PF_INET, SOCK_STREAM, 0);
154 server_socket = socket(PF_INET6, SOCK_STREAM, 0);
156 if (server_socket < 0) {
161 /* Fast rebinding for debug mode, could cause invalid packets. */
162 if (global_log_level >= LOG_DEBUG1_LEVEL) {
163 int socket_option = 1;
164 setsockopt(server_socket, SOL_SOCKET, SO_REUSEADDR,
165 &socket_option, sizeof(socket_option));
168 /* Bind to the listen socket. */
169 memset(&server_in, 0, sizeof(server_in));
171 server_in.sin_family = AF_INET; /* IPv4 only */
172 server_in.sin_addr.s_addr = htonl(INADDR_ANY); /* bind to any address */
173 server_in.sin_port = htons((uint16_t)port); /* port to bind to */
175 server_in.sin6_family = AF_INET6; /* IPv6 (and IPv4) */
176 server_in.sin6_addr = in6addr_any; /* bind to any address */
177 server_in.sin6_port = htons((uint16_t)port); /* port to bind to */
179 if (bind(server_socket, (struct sockaddr *)&server_in,
180 sizeof(server_in)) != 0) {
184 /* And accept connections. */
185 if (listen(server_socket, 5) != 0) {
190 if (global_log_level >= LOG_DEBUG1_LEVEL) {
191 printf("tlsproxy %s\n", VERSION);
192 printf("Listening for connections on port %d.\n", port);
194 if (global_proxy_host != NULL && global_proxy_port != NULL) {
195 printf("Using proxy: %s:%s.\n", global_proxy_host,
201 /* Accept new connection. */
202 client_socket = accept(server_socket, NULL, NULL);
203 if (client_socket < 0) {
208 /* No lock necessary, we only have one producer! */
210 ringbuffer[ringbuffer_write] = client_socket;
211 ringbuffer_write = (ringbuffer_write + 1) % RINGBUFFER_SIZE;
215 close(server_socket);
217 /* Poison all threads and shut them down. */
218 for (i = 0; i < thread_count; i++) {
220 ringbuffer[ringbuffer_write] = -1; /* poison */
221 ringbuffer_write = (ringbuffer_write + 1) % RINGBUFFER_SIZE;
224 for (i = 0; i < thread_count; i++) {
225 errno = pthread_join(threads[i], NULL);
227 perror("pthread_join()");
231 sem_del(ringbuffer_full);
232 sem_del(ringbuffer_free);
233 sem_del(ringbuffer_lock);
237 deinitialize_gnutls();
239 free(global_proxy_host);
240 free(global_proxy_port);
246 static void sigint_handler(int signal_number) {
253 static void parse_arguments(int argc, char **argv) {
256 /* Default values. */
259 global_log_level = LOG_DEBUG_LEVEL;
261 global_log_level = LOG_WARNING_LEVEL;
263 global_passthrough_unknown = 0;
265 while ((option = getopt(argc, argv, "a:d:p:t:uh?")) != -1) {
268 http_digest_authorization = slurp_file(optarg);
269 if (http_digest_authorization == NULL) {
270 fprintf(stderr, "failed to open authorization file '%s': ",
274 } else if (strlen(http_digest_authorization) == 0) {
275 fprintf(stderr, "empty authorization file '%s'\n",
280 /* Just in case the file has a trailing newline. */
281 strtok(http_digest_authorization, "\r\n");
286 global_log_level = atoi(optarg);
287 if (global_log_level < 0) {
288 fprintf(stderr, "-d positive number required: '%s'\n",
297 /* -p must have the format host:port. */
298 if ((position = strchr(optarg, ':')) == NULL
299 || optarg == position
300 || strlen(position + 1) == 0
301 || atoi(position + 1) <= 0
302 || atoi(position + 1) > 0xffff) {
303 fprintf(stderr, "invalid -p: '%s', format host:port\n",
308 global_proxy_host = malloc((size_t)(position - optarg) + 1);
309 if (global_proxy_host == NULL) {
313 memcpy(global_proxy_host, optarg, (size_t)(position - optarg));
314 global_proxy_host[position - optarg] = '\0';
316 global_proxy_port = malloc(strlen(position + 1) + 1);
317 if (global_proxy_port == NULL) {
321 strcpy(global_proxy_port, position + 1);
326 if (atoi(optarg) <= 0) {
327 fprintf(stderr, "-t positive number required: '%s'\n",
331 thread_count = (size_t)atoi(optarg);
335 global_passthrough_unknown = 1;
340 print_usage(argv[0]);
345 if (optind >= argc) {
346 fprintf(stderr, "port missing\n");
350 static void print_usage(const char *argv) {
351 fprintf(stderr, "tlsproxy %s, a certificate checking TLS proxy\n",
353 fprintf(stderr, "Usage: %s [-a file] [-d level] [-p host:port] [-t count] [-u] port\n",
355 fprintf(stderr, "\n");
356 fprintf(stderr, "-a digest authentication file [default: none]\n");
357 fprintf(stderr, "-d debug level: 0=errors only, 2=debug [default: 1]\n");
358 fprintf(stderr, "-p proxy hostname and port\n");
359 fprintf(stderr, "-t number of threads [default: 10]\n");
360 fprintf(stderr, "-u passthrough connection if no certificate is stored \
361 [default: error]\n");
362 fprintf(stderr, " WARNING: might be a security problem!\n");
365 static void initialize_gnutls(void) {
369 /* Thread safe setup. Must be called before gnutls_global_init(). */
370 error = gcry_control(GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
372 fprintf(stderr, "gcry_control(): %s/%s\n", gcry_strsource(error),
373 gcry_strerror(error));
376 /* Prevent usage of blocking /dev/random. */
377 error = gcry_control(GCRYCTL_ENABLE_QUICK_RANDOM, 0);
379 fprintf(stderr, "gcry_control(): %s/%s\n", gcry_strsource(error),
380 gcry_strerror(error));
384 /* Initialize GnuTLS. */
385 result = gnutls_global_init();
386 GNUTLS_ERROR_EXIT(result, "gnutls_global_init()");
388 /* Setup GnuTLS cipher suites. */
389 result = gnutls_priority_init(&global_tls_priority_cache, "NORMAL", NULL);
390 GNUTLS_ERROR_EXIT(result, "gnutls_priority_init()");
392 /* Generate Diffie-Hellman parameters. */
393 result = gnutls_dh_params_init(&global_tls_dh_params);
394 GNUTLS_ERROR_EXIT(result, "gnutls_dh_params_init()");
395 result = gnutls_dh_params_generate2(global_tls_dh_params, DH_SIZE);
396 GNUTLS_ERROR_EXIT(result, "gnutls_dh_params_generate2()");
398 static void deinitialize_gnutls(void) {
399 gnutls_dh_params_deinit(global_tls_dh_params);
400 gnutls_priority_deinit(global_tls_priority_cache);
402 gnutls_global_deinit();
405 static void *worker_thread(void *unused) {
411 /* Get next element from ring buffer. */
414 client_socket = ringbuffer[ringbuffer_read];
415 ringbuffer_read = (ringbuffer_read + 1) % RINGBUFFER_SIZE;
419 /* Negative value indicates we should shut down our thread. */
420 if (client_socket < 0) {
424 handle_connection(client_socket);
430 static char *slurp_file(const char *path) {
433 char *content = NULL;
435 FILE *file = fopen(path, "r");
440 ct_assert(sizeof(stat.st_size) <= sizeof(size_t));
442 if (fstat(fileno(file), &stat) != 0) {
445 if (stat.st_size < 0) { /* just in case ... */
447 } else if ((size_t)stat.st_size >= SIZE_MAX - 1) {
452 content = malloc((size_t)stat.st_size + 1);
453 if (content == NULL) {
458 size_read = fread(content, 1, (size_t)stat.st_size, file);
459 if (size_read != (size_t)stat.st_size) {
464 content[size_read] = '\0';