When using a socket as a FILE *, the stdio functions will sometimes try to do
[asterisk/asterisk.git] / main / tcptls.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2007 - 2008, Digium, Inc.
5  *
6  * Luigi Rizzo (TCP and TLS server code)
7  * Brett Bryant <brettbryant@gmail.com> (updated for client support)
8  *
9  * See http://www.asterisk.org for more information about
10  * the Asterisk project. Please do not directly contact
11  * any of the maintainers of this project for assistance;
12  * the project provides a web site, mailing lists and IRC
13  * channels for your use.
14  *
15  * This program is free software, distributed under the terms of
16  * the GNU General Public License Version 2. See the LICENSE file
17  * at the top of the source tree.
18  */
19
20 /*!
21  * \file
22  * \brief Code to support TCP and TLS server/client
23  *
24  * \author Luigi Rizzo
25  * \author Brett Bryant <brettbryant@gmail.com>
26  */
27
28 #include "asterisk.h"
29
30 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
31
32 #ifdef HAVE_FCNTL_H
33 #include <fcntl.h>
34 #endif
35
36 #include <sys/signal.h>
37
38 #include "asterisk/compat.h"
39 #include "asterisk/tcptls.h"
40 #include "asterisk/http.h"
41 #include "asterisk/utils.h"
42 #include "asterisk/strings.h"
43 #include "asterisk/options.h"
44 #include "asterisk/manager.h"
45 #include "asterisk/astobj2.h"
46
47 /*! \brief
48  * replacement read/write functions for SSL support.
49  * We use wrappers rather than SSL_read/SSL_write directly so
50  * we can put in some debugging.
51  */
52
53 #ifdef DO_SSL
54 static HOOK_T ssl_read(void *cookie, char *buf, LEN_T len)
55 {
56         int i = SSL_read(cookie, buf, len-1);
57 #if 0
58         if (i >= 0)
59                 buf[i] = '\0';
60         ast_verb(0, "ssl read size %d returns %d <%s>\n", (int)len, i, buf);
61 #endif
62         return i;
63 }
64
65 static HOOK_T ssl_write(void *cookie, const char *buf, LEN_T len)
66 {
67 #if 0
68         char *s = alloca(len+1);
69         strncpy(s, buf, len);
70         s[len] = '\0';
71         ast_verb(0, "ssl write size %d <%s>\n", (int)len, s);
72 #endif
73         return SSL_write(cookie, buf, len);
74 }
75
76 static int ssl_close(void *cookie)
77 {
78         close(SSL_get_fd(cookie));
79         SSL_shutdown(cookie);
80         SSL_free(cookie);
81         return 0;
82 }
83 #endif  /* DO_SSL */
84
85 HOOK_T ast_tcptls_server_read(struct ast_tcptls_session_instance *tcptls_session, void *buf, size_t count)
86 {
87         if (tcptls_session->fd == -1) {
88                 ast_log(LOG_ERROR, "server_read called with an fd of -1\n");
89                 errno = EIO;
90                 return -1;
91         }
92
93 #ifdef DO_SSL
94         if (tcptls_session->ssl)
95                 return ssl_read(tcptls_session->ssl, buf, count);
96 #endif
97         return read(tcptls_session->fd, buf, count);
98 }
99
100 HOOK_T ast_tcptls_server_write(struct ast_tcptls_session_instance *tcptls_session, const void *buf, size_t count)
101 {
102         if (tcptls_session->fd == -1) {
103                 ast_log(LOG_ERROR, "server_write called with an fd of -1\n");
104                 errno = EIO;
105                 return -1;
106         }
107
108 #ifdef DO_SSL
109         if (tcptls_session->ssl)
110                 return ssl_write(tcptls_session->ssl, buf, count);
111 #endif
112         return write(tcptls_session->fd, buf, count);
113 }
114
115 static void session_instance_destructor(void *obj)
116 {
117         struct ast_tcptls_session_instance *i = obj;
118         ast_mutex_destroy(&i->lock);
119 }
120
121 /*! \brief
122 * creates a FILE * from the fd passed by the accept thread.
123 * This operation is potentially expensive (certificate verification),
124 * so we do it in the child thread context.
125 */
126 static void *handle_tls_connection(void *data)
127 {
128         struct ast_tcptls_session_instance *tcptls_session = data;
129 #ifdef DO_SSL
130         int (*ssl_setup)(SSL *) = (tcptls_session->client) ? SSL_connect : SSL_accept;
131         int ret;
132         char err[256];
133 #endif
134
135         /*
136         * open a FILE * as appropriate.
137         */
138         if (!tcptls_session->parent->tls_cfg) {
139                 tcptls_session->f = fdopen(tcptls_session->fd, "w+");
140                 setvbuf(tcptls_session->f, NULL, _IONBF, 0);
141         }
142 #ifdef DO_SSL
143         else if ( (tcptls_session->ssl = SSL_new(tcptls_session->parent->tls_cfg->ssl_ctx)) ) {
144                 SSL_set_fd(tcptls_session->ssl, tcptls_session->fd);
145                 if ((ret = ssl_setup(tcptls_session->ssl)) <= 0) {
146                         ast_verb(2, "Problem setting up ssl connection: %s\n", ERR_error_string(ERR_get_error(), err));
147                 } else {
148 #if defined(HAVE_FUNOPEN)       /* the BSD interface */
149                         tcptls_session->f = funopen(tcptls_session->ssl, ssl_read, ssl_write, NULL, ssl_close);
150
151 #elif defined(HAVE_FOPENCOOKIE) /* the glibc/linux interface */
152                         static const cookie_io_functions_t cookie_funcs = {
153                                 ssl_read, ssl_write, NULL, ssl_close
154                         };
155                         tcptls_session->f = fopencookie(tcptls_session->ssl, "w+", cookie_funcs);
156 #else
157                         /* could add other methods here */
158                         ast_debug(2, "no tcptls_session->f methods attempted!");
159 #endif
160                         if ((tcptls_session->client && !ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_DONT_VERIFY_SERVER))
161                                 || (!tcptls_session->client && ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_VERIFY_CLIENT))) {
162                                 X509 *peer;
163                                 long res;
164                                 peer = SSL_get_peer_certificate(tcptls_session->ssl);
165                                 if (!peer)
166                                         ast_log(LOG_WARNING, "No peer SSL certificate\n");
167                                 res = SSL_get_verify_result(tcptls_session->ssl);
168                                 if (res != X509_V_OK)
169                                         ast_log(LOG_ERROR, "Certificate did not verify: %s\n", X509_verify_cert_error_string(res));
170                                 if (!ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_IGNORE_COMMON_NAME)) {
171                                         ASN1_STRING *str;
172                                         unsigned char *str2;
173                                         X509_NAME *name = X509_get_subject_name(peer);
174                                         int pos = -1;
175                                         int found = 0;
176                                 
177                                         for (;;) {
178                                                 /* Walk the certificate to check all available "Common Name" */
179                                                 /* XXX Probably should do a gethostbyname on the hostname and compare that as well */
180                                                 pos = X509_NAME_get_index_by_NID(name, NID_commonName, pos);
181                                                 if (pos < 0)
182                                                         break;
183                                                 str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, pos));
184                                                 ASN1_STRING_to_UTF8(&str2, str);
185                                                 if (str2) {
186                                                         if (!strcasecmp(tcptls_session->parent->hostname, (char *) str2))
187                                                                 found = 1;
188                                                         ast_debug(3, "SSL Common Name compare s1='%s' s2='%s'\n", tcptls_session->parent->hostname, str2);
189                                                         OPENSSL_free(str2);
190                                                 }
191                                                 if (found)
192                                                         break;
193                                         }
194                                         if (!found) {
195                                                 ast_log(LOG_ERROR, "Certificate common name did not match (%s)\n", tcptls_session->parent->hostname);
196                                                 if (peer)
197                                                         X509_free(peer);
198                                                 fclose(tcptls_session->f);
199                                                 return NULL;
200                                         }
201                                 }
202                                 if (peer)
203                                         X509_free(peer);
204                         }
205                 }
206                 if (!tcptls_session->f) /* no success opening descriptor stacking */
207                         SSL_free(tcptls_session->ssl);
208    }
209 #endif /* DO_SSL */
210
211         if (!tcptls_session->f) {
212                 close(tcptls_session->fd);
213                 ast_log(LOG_WARNING, "FILE * open failed!\n");
214                 ao2_ref(tcptls_session, -1);
215                 return NULL;
216         }
217
218         if (tcptls_session && tcptls_session->parent->worker_fn)
219                 return tcptls_session->parent->worker_fn(tcptls_session);
220         else
221                 return tcptls_session;
222 }
223
224 void *ast_tcptls_server_root(void *data)
225 {
226         struct ast_tcptls_session_args *desc = data;
227         int fd;
228         struct sockaddr_in sin;
229         socklen_t sinlen;
230         struct ast_tcptls_session_instance *tcptls_session;
231         pthread_t launched;
232         
233         for (;;) {
234                 int i, flags;
235
236                 if (desc->periodic_fn)
237                         desc->periodic_fn(desc);
238                 i = ast_wait_for_input(desc->accept_fd, desc->poll_timeout);
239                 if (i <= 0)
240                         continue;
241                 sinlen = sizeof(sin);
242                 fd = accept(desc->accept_fd, (struct sockaddr *) &sin, &sinlen);
243                 if (fd < 0) {
244                         if ((errno != EAGAIN) && (errno != EINTR))
245                                 ast_log(LOG_WARNING, "Accept failed: %s\n", strerror(errno));
246                         continue;
247                 }
248                 tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor);
249                 if (!tcptls_session) {
250                         ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
251                         close(fd);
252                         continue;
253                 }
254
255                 ast_mutex_init(&tcptls_session->lock);
256
257                 flags = fcntl(fd, F_GETFL);
258                 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
259                 tcptls_session->fd = fd;
260                 tcptls_session->parent = desc;
261                 memcpy(&tcptls_session->remote_address, &sin, sizeof(tcptls_session->remote_address));
262
263                 tcptls_session->client = 0;
264                         
265                 if (ast_pthread_create_detached_background(&launched, NULL, handle_tls_connection, tcptls_session)) {
266                         ast_log(LOG_WARNING, "Unable to launch helper thread: %s\n", strerror(errno));
267                         close(tcptls_session->fd);
268                         ao2_ref(tcptls_session, -1);
269                 }
270         }
271         return NULL;
272 }
273
274 static int __ssl_setup(struct ast_tls_config *cfg, int client)
275 {
276 #ifndef DO_SSL
277         cfg->enabled = 0;
278         return 0;
279 #else
280         if (!cfg->enabled)
281                 return 0;
282
283         SSL_load_error_strings();
284         SSLeay_add_ssl_algorithms();
285
286         if (!(cfg->ssl_ctx = SSL_CTX_new( client ? SSLv23_client_method() : SSLv23_server_method() ))) {
287                 ast_debug(1, "Sorry, SSL_CTX_new call returned null...\n");
288                 cfg->enabled = 0;
289                 return 0;
290         }
291         if (!ast_strlen_zero(cfg->certfile)) {
292                 if (SSL_CTX_use_certificate_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
293                     SSL_CTX_use_PrivateKey_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
294                     SSL_CTX_check_private_key(cfg->ssl_ctx) == 0 ) {
295                         if (!client) {
296                                 /* Clients don't need a certificate, but if its setup we can use it */
297                                 ast_verb(0, "SSL cert error <%s>", cfg->certfile);
298                                 sleep(2);
299                                 cfg->enabled = 0;
300                                 return 0;
301                         }
302                 }
303         }
304         if (!ast_strlen_zero(cfg->cipher)) {
305                 if (SSL_CTX_set_cipher_list(cfg->ssl_ctx, cfg->cipher) == 0 ) {
306                         if (!client) {
307                                 ast_verb(0, "SSL cipher error <%s>", cfg->cipher);
308                                 sleep(2);
309                                 cfg->enabled = 0;
310                                 return 0;
311                         }
312                 }
313         }
314         if (!ast_strlen_zero(cfg->cafile) || !ast_strlen_zero(cfg->capath)) {
315                 if (SSL_CTX_load_verify_locations(cfg->ssl_ctx, S_OR(cfg->cafile, NULL), S_OR(cfg->capath,NULL)) == 0)
316                         ast_verb(0, "SSL CA file(%s)/path(%s) error\n", cfg->cafile, cfg->capath);
317         }
318
319         ast_verb(0, "SSL certificate ok\n");
320         return 1;
321 #endif
322 }
323
324 int ast_ssl_setup(struct ast_tls_config *cfg)
325 {
326         return __ssl_setup(cfg, 0);
327 }
328
329 /*! \brief A generic client routine for a TCP client
330  *  and starts a thread for handling accept()
331  */
332 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct ast_tcptls_session_args *desc)
333 {
334         int flags;
335         int x = 1;
336         struct ast_tcptls_session_instance *tcptls_session = NULL;
337
338         /* Do nothing if nothing has changed */
339         if (!memcmp(&desc->old_address, &desc->remote_address, sizeof(desc->old_address))) {
340                 ast_debug(1, "Nothing changed in %s\n", desc->name);
341                 return NULL;
342         }
343
344         desc->old_address = desc->remote_address;
345
346         if (desc->accept_fd != -1)
347                 close(desc->accept_fd);
348
349         desc->accept_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
350         if (desc->accept_fd < 0) {
351                 ast_log(LOG_WARNING, "Unable to allocate socket for %s: %s\n",
352                         desc->name, strerror(errno));
353                 return NULL;
354         }
355
356         /* if a local address was specified, bind to it so the connection will
357            originate from the desired address */
358         if (desc->local_address.sin_family != 0) {
359                 setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
360                 if (bind(desc->accept_fd, (struct sockaddr *) &desc->local_address, sizeof(desc->local_address))) {
361                         ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
362                         desc->name,
363                                 ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
364                                 strerror(errno));
365                         goto error;
366                 }
367         }
368
369         if (connect(desc->accept_fd, (const struct sockaddr *) &desc->remote_address, sizeof(desc->remote_address))) {
370                 ast_log(LOG_ERROR, "Unable to connect %s to %s:%d: %s\n",
371                         desc->name,
372                         ast_inet_ntoa(desc->remote_address.sin_addr), ntohs(desc->remote_address.sin_port),
373                         strerror(errno));
374                 goto error;
375         }
376
377         if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor)))
378                 goto error;
379
380         ast_mutex_init(&tcptls_session->lock);
381
382         flags = fcntl(desc->accept_fd, F_GETFL);
383         fcntl(desc->accept_fd, F_SETFL, flags & ~O_NONBLOCK);
384
385         tcptls_session->fd = desc->accept_fd;
386         tcptls_session->parent = desc;
387         tcptls_session->parent->worker_fn = NULL;
388         memcpy(&tcptls_session->remote_address, &desc->remote_address, sizeof(tcptls_session->remote_address));
389
390         tcptls_session->client = 1;
391
392         if (desc->tls_cfg) {
393                 desc->tls_cfg->enabled = 1;
394                 __ssl_setup(desc->tls_cfg, 1);
395         }
396
397         ao2_ref(tcptls_session, +1);
398         if (!handle_tls_connection(tcptls_session))
399                 goto error;
400
401         return tcptls_session;
402
403 error:
404         close(desc->accept_fd);
405         desc->accept_fd = -1;
406         if (tcptls_session)
407                 ao2_ref(tcptls_session, -1);
408         return NULL;
409 }
410
411 /*! \brief
412  * This is a generic (re)start routine for a TCP server,
413  * which does the socket/bind/listen and starts a thread for handling
414  * accept().
415  */
416 void ast_tcptls_server_start(struct ast_tcptls_session_args *desc)
417 {
418         int flags;
419         int x = 1;
420         
421         /* Do nothing if nothing has changed */
422         if (!memcmp(&desc->old_address, &desc->local_address, sizeof(desc->old_address))) {
423                 ast_debug(1, "Nothing changed in %s\n", desc->name);
424                 return;
425         }
426         
427         desc->old_address = desc->local_address;
428         
429         /* Shutdown a running server if there is one */
430         if (desc->master != AST_PTHREADT_NULL) {
431                 pthread_cancel(desc->master);
432                 pthread_kill(desc->master, SIGURG);
433                 pthread_join(desc->master, NULL);
434         }
435         
436         if (desc->accept_fd != -1)
437                 close(desc->accept_fd);
438
439         /* If there's no new server, stop here */
440         if (desc->local_address.sin_family == 0) {
441                 ast_debug(2, "Server disabled:  %s\n", desc->name);
442                 return;
443         }
444
445         desc->accept_fd = socket(AF_INET, SOCK_STREAM, 0);
446         if (desc->accept_fd < 0) {
447                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n", desc->name, strerror(errno));
448                 return;
449         }
450         
451         setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
452         if (bind(desc->accept_fd, (struct sockaddr *) &desc->local_address, sizeof(desc->local_address))) {
453                 ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
454                         desc->name,
455                         ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
456                         strerror(errno));
457                 goto error;
458         }
459         if (listen(desc->accept_fd, 10)) {
460                 ast_log(LOG_ERROR, "Unable to listen for %s!\n", desc->name);
461                 goto error;
462         }
463         flags = fcntl(desc->accept_fd, F_GETFL);
464         fcntl(desc->accept_fd, F_SETFL, flags | O_NONBLOCK);
465         if (ast_pthread_create_background(&desc->master, NULL, desc->accept_fn, desc)) {
466                 ast_log(LOG_ERROR, "Unable to launch thread for %s on %s:%d: %s\n",
467                         desc->name,
468                         ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
469                         strerror(errno));
470                 goto error;
471         }
472         return;
473
474 error:
475         close(desc->accept_fd);
476         desc->accept_fd = -1;
477 }
478
479 /*! \brief Shutdown a running server if there is one */
480 void ast_tcptls_server_stop(struct ast_tcptls_session_args *desc)
481 {
482         if (desc->master != AST_PTHREADT_NULL) {
483                 pthread_cancel(desc->master);
484                 pthread_kill(desc->master, SIGURG);
485                 pthread_join(desc->master, NULL);
486         }
487         if (desc->accept_fd != -1)
488                 close(desc->accept_fd);
489         desc->accept_fd = -1;
490         ast_debug(2, "Stopped server :: %s\n", desc->name);
491 }