tcptls: Avoiding ERR_remove_state in OpenSSL.
[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 /*** MODULEINFO
29         <support_level>core</support_level>
30  ***/
31
32 #include "asterisk.h"
33
34 ASTERISK_REGISTER_FILE()
35
36 #ifdef HAVE_FCNTL_H
37 #include <fcntl.h>
38 #endif
39
40 #include <signal.h>
41 #include <sys/signal.h>
42
43 #include "asterisk/compat.h"
44 #include "asterisk/tcptls.h"
45 #include "asterisk/http.h"
46 #include "asterisk/utils.h"
47 #include "asterisk/strings.h"
48 #include "asterisk/options.h"
49 #include "asterisk/manager.h"
50 #include "asterisk/astobj2.h"
51 #include "asterisk/pbx.h"
52
53 /*! ao2 object used for the FILE stream fopencookie()/funopen() cookie. */
54 struct ast_tcptls_stream {
55         /*! SSL state if not NULL */
56         SSL *ssl;
57         /*!
58          * \brief Start time from when an I/O sequence must complete
59          * by struct ast_tcptls_stream.timeout.
60          *
61          * \note If struct ast_tcptls_stream.start.tv_sec is zero then
62          * start time is the current I/O request.
63          */
64         struct timeval start;
65         /*!
66          * \brief The socket returned by accept().
67          *
68          * \note Set to -1 if the stream is closed.
69          */
70         int fd;
71         /*!
72          * \brief Timeout in ms relative to struct ast_tcptls_stream.start
73          * to wait for an event on struct ast_tcptls_stream.fd.
74          *
75          * \note Set to -1 to disable timeout.
76          * \note The socket needs to be set to non-blocking for the timeout
77          * feature to work correctly.
78          */
79         int timeout;
80         /*! TRUE if stream can exclusively wait for fd input. */
81         int exclusive_input;
82 };
83
84 void ast_tcptls_stream_set_timeout_disable(struct ast_tcptls_stream *stream)
85 {
86         ast_assert(stream != NULL);
87
88         stream->timeout = -1;
89 }
90
91 void ast_tcptls_stream_set_timeout_inactivity(struct ast_tcptls_stream *stream, int timeout)
92 {
93         ast_assert(stream != NULL);
94
95         stream->start.tv_sec = 0;
96         stream->timeout = timeout;
97 }
98
99 void ast_tcptls_stream_set_timeout_sequence(struct ast_tcptls_stream *stream, struct timeval start, int timeout)
100 {
101         ast_assert(stream != NULL);
102
103         stream->start = start;
104         stream->timeout = timeout;
105 }
106
107 void ast_tcptls_stream_set_exclusive_input(struct ast_tcptls_stream *stream, int exclusive_input)
108 {
109         ast_assert(stream != NULL);
110
111         stream->exclusive_input = exclusive_input;
112 }
113
114 /*!
115  * \internal
116  * \brief fopencookie()/funopen() stream read function.
117  *
118  * \param cookie Stream control data.
119  * \param buf Where to put read data.
120  * \param size Size of the buffer.
121  *
122  * \retval number of bytes put into buf.
123  * \retval 0 on end of file.
124  * \retval -1 on error.
125  */
126 static HOOK_T tcptls_stream_read(void *cookie, char *buf, LEN_T size)
127 {
128         struct ast_tcptls_stream *stream = cookie;
129         struct timeval start;
130         int ms;
131         int res;
132
133         if (!size) {
134                 /* You asked for no data you got no data. */
135                 return 0;
136         }
137
138         if (!stream || stream->fd == -1) {
139                 errno = EBADF;
140                 return -1;
141         }
142
143         if (stream->start.tv_sec) {
144                 start = stream->start;
145         } else {
146                 start = ast_tvnow();
147         }
148
149 #if defined(DO_SSL)
150         if (stream->ssl) {
151                 for (;;) {
152                         res = SSL_read(stream->ssl, buf, size);
153                         if (0 < res) {
154                                 /* We read some payload data. */
155                                 return res;
156                         }
157                         switch (SSL_get_error(stream->ssl, res)) {
158                         case SSL_ERROR_ZERO_RETURN:
159                                 /* Report EOF for a shutdown */
160                                 ast_debug(1, "TLS clean shutdown alert reading data\n");
161                                 return 0;
162                         case SSL_ERROR_WANT_READ:
163                                 if (!stream->exclusive_input) {
164                                         /* We cannot wait for data now. */
165                                         errno = EAGAIN;
166                                         return -1;
167                                 }
168                                 while ((ms = ast_remaining_ms(start, stream->timeout))) {
169                                         res = ast_wait_for_input(stream->fd, ms);
170                                         if (0 < res) {
171                                                 /* Socket is ready to be read. */
172                                                 break;
173                                         }
174                                         if (res < 0) {
175                                                 if (errno == EINTR || errno == EAGAIN) {
176                                                         /* Try again. */
177                                                         continue;
178                                                 }
179                                                 ast_debug(1, "TLS socket error waiting for read data: %s\n",
180                                                         strerror(errno));
181                                                 return -1;
182                                         }
183                                 }
184                                 break;
185                         case SSL_ERROR_WANT_WRITE:
186                                 while ((ms = ast_remaining_ms(start, stream->timeout))) {
187                                         res = ast_wait_for_output(stream->fd, ms);
188                                         if (0 < res) {
189                                                 /* Socket is ready to be written. */
190                                                 break;
191                                         }
192                                         if (res < 0) {
193                                                 if (errno == EINTR || errno == EAGAIN) {
194                                                         /* Try again. */
195                                                         continue;
196                                                 }
197                                                 ast_debug(1, "TLS socket error waiting for write space: %s\n",
198                                                         strerror(errno));
199                                                 return -1;
200                                         }
201                                 }
202                                 break;
203                         default:
204                                 /* Report EOF for an undecoded SSL or transport error. */
205                                 ast_debug(1, "TLS transport or SSL error reading data\n");
206                                 return 0;
207                         }
208                         if (!ms) {
209                                 /* Report EOF for a timeout */
210                                 ast_debug(1, "TLS timeout reading data\n");
211                                 return 0;
212                         }
213                 }
214         }
215 #endif  /* defined(DO_SSL) */
216
217         for (;;) {
218                 res = read(stream->fd, buf, size);
219                 if (0 <= res || !stream->exclusive_input) {
220                         /* Got data or we cannot wait for it. */
221                         return res;
222                 }
223                 if (errno != EINTR && errno != EAGAIN) {
224                         /* Not a retryable error. */
225                         ast_debug(1, "TCP socket error reading data: %s\n",
226                                 strerror(errno));
227                         return -1;
228                 }
229                 ms = ast_remaining_ms(start, stream->timeout);
230                 if (!ms) {
231                         /* Report EOF for a timeout */
232                         ast_debug(1, "TCP timeout reading data\n");
233                         return 0;
234                 }
235                 ast_wait_for_input(stream->fd, ms);
236         }
237 }
238
239 /*!
240  * \internal
241  * \brief fopencookie()/funopen() stream write function.
242  *
243  * \param cookie Stream control data.
244  * \param buf Where to get data to write.
245  * \param size Size of the buffer.
246  *
247  * \retval number of bytes written from buf.
248  * \retval -1 on error.
249  */
250 static HOOK_T tcptls_stream_write(void *cookie, const char *buf, LEN_T size)
251 {
252         struct ast_tcptls_stream *stream = cookie;
253         struct timeval start;
254         int ms;
255         int res;
256         int written;
257         int remaining;
258
259         if (!size) {
260                 /* You asked to write no data you wrote no data. */
261                 return 0;
262         }
263
264         if (!stream || stream->fd == -1) {
265                 errno = EBADF;
266                 return -1;
267         }
268
269         if (stream->start.tv_sec) {
270                 start = stream->start;
271         } else {
272                 start = ast_tvnow();
273         }
274
275 #if defined(DO_SSL)
276         if (stream->ssl) {
277                 written = 0;
278                 remaining = size;
279                 for (;;) {
280                         res = SSL_write(stream->ssl, buf + written, remaining);
281                         if (res == remaining) {
282                                 /* Everything was written. */
283                                 return size;
284                         }
285                         if (0 < res) {
286                                 /* Successfully wrote part of the buffer.  Try to write the rest. */
287                                 written += res;
288                                 remaining -= res;
289                                 continue;
290                         }
291                         switch (SSL_get_error(stream->ssl, res)) {
292                         case SSL_ERROR_ZERO_RETURN:
293                                 ast_debug(1, "TLS clean shutdown alert writing data\n");
294                                 if (written) {
295                                         /* Report partial write. */
296                                         return written;
297                                 }
298                                 errno = EBADF;
299                                 return -1;
300                         case SSL_ERROR_WANT_READ:
301                                 ms = ast_remaining_ms(start, stream->timeout);
302                                 if (!ms) {
303                                         /* Report partial write. */
304                                         ast_debug(1, "TLS timeout writing data (want read)\n");
305                                         return written;
306                                 }
307                                 ast_wait_for_input(stream->fd, ms);
308                                 break;
309                         case SSL_ERROR_WANT_WRITE:
310                                 ms = ast_remaining_ms(start, stream->timeout);
311                                 if (!ms) {
312                                         /* Report partial write. */
313                                         ast_debug(1, "TLS timeout writing data (want write)\n");
314                                         return written;
315                                 }
316                                 ast_wait_for_output(stream->fd, ms);
317                                 break;
318                         default:
319                                 /* Undecoded SSL or transport error. */
320                                 ast_debug(1, "TLS transport or SSL error writing data\n");
321                                 if (written) {
322                                         /* Report partial write. */
323                                         return written;
324                                 }
325                                 errno = EBADF;
326                                 return -1;
327                         }
328                 }
329         }
330 #endif  /* defined(DO_SSL) */
331
332         written = 0;
333         remaining = size;
334         for (;;) {
335                 res = write(stream->fd, buf + written, remaining);
336                 if (res == remaining) {
337                         /* Yay everything was written. */
338                         return size;
339                 }
340                 if (0 < res) {
341                         /* Successfully wrote part of the buffer.  Try to write the rest. */
342                         written += res;
343                         remaining -= res;
344                         continue;
345                 }
346                 if (errno != EINTR && errno != EAGAIN) {
347                         /* Not a retryable error. */
348                         ast_debug(1, "TCP socket error writing: %s\n", strerror(errno));
349                         if (written) {
350                                 return written;
351                         }
352                         return -1;
353                 }
354                 ms = ast_remaining_ms(start, stream->timeout);
355                 if (!ms) {
356                         /* Report partial write. */
357                         ast_debug(1, "TCP timeout writing data\n");
358                         return written;
359                 }
360                 ast_wait_for_output(stream->fd, ms);
361         }
362 }
363
364 /*!
365  * \internal
366  * \brief fopencookie()/funopen() stream close function.
367  *
368  * \param cookie Stream control data.
369  *
370  * \retval 0 on success.
371  * \retval -1 on error.
372  */
373 static int tcptls_stream_close(void *cookie)
374 {
375         struct ast_tcptls_stream *stream = cookie;
376
377         if (!stream) {
378                 errno = EBADF;
379                 return -1;
380         }
381
382         if (stream->fd != -1) {
383 #if defined(DO_SSL)
384                 if (stream->ssl) {
385                         int res;
386
387                         /*
388                          * According to the TLS standard, it is acceptable for an
389                          * application to only send its shutdown alert and then
390                          * close the underlying connection without waiting for
391                          * the peer's response (this way resources can be saved,
392                          * as the process can already terminate or serve another
393                          * connection).
394                          */
395                         res = SSL_shutdown(stream->ssl);
396                         if (res < 0) {
397                                 ast_log(LOG_ERROR, "SSL_shutdown() failed: %d\n",
398                                         SSL_get_error(stream->ssl, res));
399                         }
400
401                         if (!stream->ssl->server) {
402                                 /* For client threads, ensure that the error stack is cleared */
403 #if OPENSSL_VERSION_NUMBER >= 0x10000000L
404                                 ERR_remove_thread_state(NULL);
405 #else
406                                 ERR_remove_state(0);
407 #endif  /* OPENSSL_VERSION_NUMBER >= 0x10000000L */
408                         }
409
410                         SSL_free(stream->ssl);
411                         stream->ssl = NULL;
412                 }
413 #endif  /* defined(DO_SSL) */
414
415                 /*
416                  * Issuing shutdown() is necessary here to avoid a race
417                  * condition where the last data written may not appear
418                  * in the TCP stream.  See ASTERISK-23548
419                  */
420                 shutdown(stream->fd, SHUT_RDWR);
421                 if (close(stream->fd)) {
422                         ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
423                 }
424                 stream->fd = -1;
425         }
426         ao2_t_ref(stream, -1, "Closed tcptls stream cookie");
427
428         return 0;
429 }
430
431 /*!
432  * \internal
433  * \brief fopencookie()/funopen() stream destructor function.
434  *
435  * \param cookie Stream control data.
436  *
437  * \return Nothing
438  */
439 static void tcptls_stream_dtor(void *cookie)
440 {
441 #ifdef AST_DEVMODE
442         /* Since the ast_assert below is the only one using stream,
443          * and ast_assert is only available with AST_DEVMODE, we
444          * put this in a conditional to avoid compiler warnings. */
445         struct ast_tcptls_stream *stream = cookie;
446 #endif
447
448         ast_assert(stream->fd == -1);
449 }
450
451 /*!
452  * \internal
453  * \brief fopencookie()/funopen() stream allocation function.
454  *
455  * \retval stream_cookie on success.
456  * \retval NULL on error.
457  */
458 static struct ast_tcptls_stream *tcptls_stream_alloc(void)
459 {
460         struct ast_tcptls_stream *stream;
461
462         stream = ao2_alloc_options(sizeof(*stream), tcptls_stream_dtor,
463                 AO2_ALLOC_OPT_LOCK_NOLOCK);
464         if (stream) {
465                 stream->fd = -1;
466                 stream->timeout = -1;
467         }
468         return stream;
469 }
470
471 /*!
472  * \internal
473  * \brief Open a custom FILE stream for tcptls.
474  *
475  * \param stream Stream cookie control data.
476  * \param ssl SSL state if not NULL.
477  * \param fd Socket file descriptor.
478  * \param timeout ms to wait for an event on fd. -1 if timeout disabled.
479  *
480  * \retval fp on success.
481  * \retval NULL on error.
482  */
483 static FILE *tcptls_stream_fopen(struct ast_tcptls_stream *stream, SSL *ssl, int fd, int timeout)
484 {
485         FILE *fp;
486
487 #if defined(HAVE_FOPENCOOKIE)   /* the glibc/linux interface */
488         static const cookie_io_functions_t cookie_funcs = {
489                 tcptls_stream_read,
490                 tcptls_stream_write,
491                 NULL,
492                 tcptls_stream_close
493         };
494 #endif  /* defined(HAVE_FOPENCOOKIE) */
495
496         if (fd == -1) {
497                 /* Socket not open. */
498                 return NULL;
499         }
500
501         stream->ssl = ssl;
502         stream->fd = fd;
503         stream->timeout = timeout;
504         ao2_t_ref(stream, +1, "Opening tcptls stream cookie");
505
506 #if defined(HAVE_FUNOPEN)       /* the BSD interface */
507         fp = funopen(stream, tcptls_stream_read, tcptls_stream_write, NULL,
508                 tcptls_stream_close);
509 #elif defined(HAVE_FOPENCOOKIE) /* the glibc/linux interface */
510         fp = fopencookie(stream, "w+", cookie_funcs);
511 #else
512         /* could add other methods here */
513         ast_debug(2, "No stream FILE methods attempted!\n");
514         fp = NULL;
515 #endif
516
517         if (!fp) {
518                 stream->fd = -1;
519                 ao2_t_ref(stream, -1, "Failed to open tcptls stream cookie");
520         }
521         return fp;
522 }
523
524 HOOK_T ast_tcptls_server_read(struct ast_tcptls_session_instance *tcptls_session, void *buf, size_t count)
525 {
526         if (!tcptls_session->stream_cookie || tcptls_session->stream_cookie->fd == -1) {
527                 ast_log(LOG_ERROR, "TCP/TLS read called on invalid stream.\n");
528                 errno = EIO;
529                 return -1;
530         }
531
532         return tcptls_stream_read(tcptls_session->stream_cookie, buf, count);
533 }
534
535 HOOK_T ast_tcptls_server_write(struct ast_tcptls_session_instance *tcptls_session, const void *buf, size_t count)
536 {
537         if (!tcptls_session->stream_cookie || tcptls_session->stream_cookie->fd == -1) {
538                 ast_log(LOG_ERROR, "TCP/TLS write called on invalid stream.\n");
539                 errno = EIO;
540                 return -1;
541         }
542
543         return tcptls_stream_write(tcptls_session->stream_cookie, buf, count);
544 }
545
546 static void session_instance_destructor(void *obj)
547 {
548         struct ast_tcptls_session_instance *i = obj;
549
550         if (i->stream_cookie) {
551                 ao2_t_ref(i->stream_cookie, -1, "Destroying tcptls session instance");
552                 i->stream_cookie = NULL;
553         }
554         ast_free(i->overflow_buf);
555         ao2_cleanup(i->private_data);
556 }
557
558 /*! \brief
559 * creates a FILE * from the fd passed by the accept thread.
560 * This operation is potentially expensive (certificate verification),
561 * so we do it in the child thread context.
562 *
563 * \note must decrement ref count before returning NULL on error
564 */
565 static void *handle_tcptls_connection(void *data)
566 {
567         struct ast_tcptls_session_instance *tcptls_session = data;
568 #ifdef DO_SSL
569         int (*ssl_setup)(SSL *) = (tcptls_session->client) ? SSL_connect : SSL_accept;
570         int ret;
571         char err[256];
572 #endif
573
574         /* TCP/TLS connections are associated with external protocols, and
575          * should not be allowed to execute 'dangerous' functions. This may
576          * need to be pushed down into the individual protocol handlers, but
577          * this seems like a good general policy.
578          */
579         if (ast_thread_inhibit_escalations()) {
580                 ast_log(LOG_ERROR, "Failed to inhibit privilege escalations; killing connection\n");
581                 ast_tcptls_close_session_file(tcptls_session);
582                 ao2_ref(tcptls_session, -1);
583                 return NULL;
584         }
585
586         tcptls_session->stream_cookie = tcptls_stream_alloc();
587         if (!tcptls_session->stream_cookie) {
588                 ast_tcptls_close_session_file(tcptls_session);
589                 ao2_ref(tcptls_session, -1);
590                 return NULL;
591         }
592
593         /*
594         * open a FILE * as appropriate.
595         */
596         if (!tcptls_session->parent->tls_cfg) {
597                 tcptls_session->f = tcptls_stream_fopen(tcptls_session->stream_cookie, NULL,
598                         tcptls_session->fd, -1);
599                 if (tcptls_session->f) {
600                         if (setvbuf(tcptls_session->f, NULL, _IONBF, 0)) {
601                                 ast_tcptls_close_session_file(tcptls_session);
602                         }
603                 }
604         }
605 #ifdef DO_SSL
606         else if ( (tcptls_session->ssl = SSL_new(tcptls_session->parent->tls_cfg->ssl_ctx)) ) {
607                 SSL_set_fd(tcptls_session->ssl, tcptls_session->fd);
608                 if ((ret = ssl_setup(tcptls_session->ssl)) <= 0) {
609                         ast_log(LOG_ERROR, "Problem setting up ssl connection: %s\n", ERR_error_string(ERR_get_error(), err));
610                 } else if ((tcptls_session->f = tcptls_stream_fopen(tcptls_session->stream_cookie,
611                         tcptls_session->ssl, tcptls_session->fd, -1))) {
612                         if ((tcptls_session->client && !ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_DONT_VERIFY_SERVER))
613                                 || (!tcptls_session->client && ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_VERIFY_CLIENT))) {
614                                 X509 *peer;
615                                 long res;
616                                 peer = SSL_get_peer_certificate(tcptls_session->ssl);
617                                 if (!peer) {
618                                         ast_log(LOG_ERROR, "No peer SSL certificate to verify\n");
619                                         ast_tcptls_close_session_file(tcptls_session);
620                                         ao2_ref(tcptls_session, -1);
621                                         return NULL;
622                                 }
623
624                                 res = SSL_get_verify_result(tcptls_session->ssl);
625                                 if (res != X509_V_OK) {
626                                         ast_log(LOG_ERROR, "Certificate did not verify: %s\n", X509_verify_cert_error_string(res));
627                                         X509_free(peer);
628                                         ast_tcptls_close_session_file(tcptls_session);
629                                         ao2_ref(tcptls_session, -1);
630                                         return NULL;
631                                 }
632                                 if (!ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_IGNORE_COMMON_NAME)) {
633                                         ASN1_STRING *str;
634                                         unsigned char *str2;
635                                         X509_NAME *name = X509_get_subject_name(peer);
636                                         int pos = -1;
637                                         int found = 0;
638
639                                         for (;;) {
640                                                 /* Walk the certificate to check all available "Common Name" */
641                                                 /* XXX Probably should do a gethostbyname on the hostname and compare that as well */
642                                                 pos = X509_NAME_get_index_by_NID(name, NID_commonName, pos);
643                                                 if (pos < 0) {
644                                                         break;
645                                                 }
646                                                 str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, pos));
647                                                 ret = ASN1_STRING_to_UTF8(&str2, str);
648                                                 if (ret < 0) {
649                                                         continue;
650                                                 }
651
652                                                 if (str2) {
653                                                         if (strlen((char *) str2) != ret) {
654                                                                 ast_log(LOG_WARNING, "Invalid certificate common name length (contains NULL bytes?)\n");
655                                                         } else if (!strcasecmp(tcptls_session->parent->hostname, (char *) str2)) {
656                                                                 found = 1;
657                                                         }
658                                                         ast_debug(3, "SSL Common Name compare s1='%s' s2='%s'\n", tcptls_session->parent->hostname, str2);
659                                                         OPENSSL_free(str2);
660                                                 }
661                                                 if (found) {
662                                                         break;
663                                                 }
664                                         }
665                                         if (!found) {
666                                                 ast_log(LOG_ERROR, "Certificate common name did not match (%s)\n", tcptls_session->parent->hostname);
667                                                 X509_free(peer);
668                                                 ast_tcptls_close_session_file(tcptls_session);
669                                                 ao2_ref(tcptls_session, -1);
670                                                 return NULL;
671                                         }
672                                 }
673                                 X509_free(peer);
674                         }
675                 }
676                 if (!tcptls_session->f) {       /* no success opening descriptor stacking */
677                         SSL_free(tcptls_session->ssl);
678                 }
679         }
680 #endif /* DO_SSL */
681
682         if (!tcptls_session->f) {
683                 ast_tcptls_close_session_file(tcptls_session);
684                 ast_log(LOG_WARNING, "FILE * open failed!\n");
685 #ifndef DO_SSL
686                 if (tcptls_session->parent->tls_cfg) {
687                         ast_log(LOG_ERROR, "Attempted a TLS connection without OpenSSL support. This will not work!\n");
688                 }
689 #endif
690                 ao2_ref(tcptls_session, -1);
691                 return NULL;
692         }
693
694         if (tcptls_session->parent->worker_fn) {
695                 return tcptls_session->parent->worker_fn(tcptls_session);
696         } else {
697                 return tcptls_session;
698         }
699 }
700
701 void *ast_tcptls_server_root(void *data)
702 {
703         struct ast_tcptls_session_args *desc = data;
704         int fd;
705         struct ast_sockaddr addr;
706         struct ast_tcptls_session_instance *tcptls_session;
707         pthread_t launched;
708
709         for (;;) {
710                 int i, flags;
711
712                 if (desc->periodic_fn) {
713                         desc->periodic_fn(desc);
714                 }
715                 i = ast_wait_for_input(desc->accept_fd, desc->poll_timeout);
716                 if (i <= 0) {
717                         continue;
718                 }
719                 fd = ast_accept(desc->accept_fd, &addr);
720                 if (fd < 0) {
721                         if ((errno != EAGAIN) && (errno != EWOULDBLOCK) && (errno != EINTR) && (errno != ECONNABORTED)) {
722                                 ast_log(LOG_ERROR, "Accept failed: %s\n", strerror(errno));
723                                 break;
724                         }
725                         continue;
726                 }
727                 tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor);
728                 if (!tcptls_session) {
729                         ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
730                         if (close(fd)) {
731                                 ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
732                         }
733                         continue;
734                 }
735
736                 tcptls_session->overflow_buf = ast_str_create(128);
737                 flags = fcntl(fd, F_GETFL);
738                 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
739                 tcptls_session->fd = fd;
740                 tcptls_session->parent = desc;
741                 ast_sockaddr_copy(&tcptls_session->remote_address, &addr);
742
743                 tcptls_session->client = 0;
744
745                 /* This thread is now the only place that controls the single ref to tcptls_session */
746                 if (ast_pthread_create_detached_background(&launched, NULL, handle_tcptls_connection, tcptls_session)) {
747                         ast_log(LOG_ERROR, "Unable to launch helper thread: %s\n", strerror(errno));
748                         ast_tcptls_close_session_file(tcptls_session);
749                         ao2_ref(tcptls_session, -1);
750                 }
751         }
752         return NULL;
753 }
754
755 static int __ssl_setup(struct ast_tls_config *cfg, int client)
756 {
757 #ifndef DO_SSL
758         cfg->enabled = 0;
759         return 0;
760 #else
761         int disable_ssl = 0;
762  
763         if (!cfg->enabled) {
764                 return 0;
765         }
766
767         /* Get rid of an old SSL_CTX since we're about to
768          * allocate a new one
769          */
770         if (cfg->ssl_ctx) {
771                 SSL_CTX_free(cfg->ssl_ctx);
772                 cfg->ssl_ctx = NULL;
773         }
774
775         if (client) {
776 #ifndef OPENSSL_NO_SSL2
777                 if (ast_test_flag(&cfg->flags, AST_SSL_SSLV2_CLIENT)) {
778                         ast_log(LOG_WARNING, "Usage of SSLv2 is discouraged due to known vulnerabilities. Please use 'tlsv1' or leave the TLS method unspecified!\n");
779                         cfg->ssl_ctx = SSL_CTX_new(SSLv2_client_method());
780                 } else
781 #endif
782 #ifndef OPENSSL_NO_SSL3_METHOD
783                 if (ast_test_flag(&cfg->flags, AST_SSL_SSLV3_CLIENT)) {
784                         ast_log(LOG_WARNING, "Usage of SSLv3 is discouraged due to known vulnerabilities. Please use 'tlsv1' or leave the TLS method unspecified!\n");
785                         cfg->ssl_ctx = SSL_CTX_new(SSLv3_client_method());
786                 } else
787 #endif
788                 if (ast_test_flag(&cfg->flags, AST_SSL_TLSV1_CLIENT)) {
789                         cfg->ssl_ctx = SSL_CTX_new(TLSv1_client_method());
790                 } else {
791                         disable_ssl = 1;
792                         cfg->ssl_ctx = SSL_CTX_new(SSLv23_client_method());
793                 }
794         } else {
795                 disable_ssl = 1;
796                 cfg->ssl_ctx = SSL_CTX_new(SSLv23_server_method());
797         }
798
799         if (!cfg->ssl_ctx) {
800                 ast_debug(1, "Sorry, SSL_CTX_new call returned null...\n");
801                 cfg->enabled = 0;
802                 return 0;
803         }
804
805         /* Due to the POODLE vulnerability, completely disable
806          * SSLv2 and SSLv3 if we are not explicitly told to use
807          * them. SSLv23_*_method supports TLSv1+.
808          */
809         if (disable_ssl) {
810                 long ssl_opts;
811
812                 ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
813                 SSL_CTX_set_options(cfg->ssl_ctx, ssl_opts);
814         }
815
816         SSL_CTX_set_verify(cfg->ssl_ctx,
817                 ast_test_flag(&cfg->flags, AST_SSL_VERIFY_CLIENT) ? SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT : SSL_VERIFY_NONE,
818                 NULL);
819
820         if (!ast_strlen_zero(cfg->certfile)) {
821                 char *tmpprivate = ast_strlen_zero(cfg->pvtfile) ? cfg->certfile : cfg->pvtfile;
822                 if (SSL_CTX_use_certificate_chain_file(cfg->ssl_ctx, cfg->certfile) == 0) {
823                         if (!client) {
824                                 /* Clients don't need a certificate, but if its setup we can use it */
825                                 ast_log(LOG_ERROR, "TLS/SSL error loading cert file. <%s>\n", cfg->certfile);
826                                 cfg->enabled = 0;
827                                 SSL_CTX_free(cfg->ssl_ctx);
828                                 cfg->ssl_ctx = NULL;
829                                 return 0;
830                         }
831                 }
832                 if ((SSL_CTX_use_PrivateKey_file(cfg->ssl_ctx, tmpprivate, SSL_FILETYPE_PEM) == 0) || (SSL_CTX_check_private_key(cfg->ssl_ctx) == 0 )) {
833                         if (!client) {
834                                 /* Clients don't need a private key, but if its setup we can use it */
835                                 ast_log(LOG_ERROR, "TLS/SSL error loading private key file. <%s>\n", tmpprivate);
836                                 cfg->enabled = 0;
837                                 SSL_CTX_free(cfg->ssl_ctx);
838                                 cfg->ssl_ctx = NULL;
839                                 return 0;
840                         }
841                 }
842         }
843         if (!ast_strlen_zero(cfg->cipher)) {
844                 if (SSL_CTX_set_cipher_list(cfg->ssl_ctx, cfg->cipher) == 0 ) {
845                         if (!client) {
846                                 ast_log(LOG_ERROR, "TLS/SSL cipher error <%s>\n", cfg->cipher);
847                                 cfg->enabled = 0;
848                                 SSL_CTX_free(cfg->ssl_ctx);
849                                 cfg->ssl_ctx = NULL;
850                                 return 0;
851                         }
852                 }
853         }
854         if (!ast_strlen_zero(cfg->cafile) || !ast_strlen_zero(cfg->capath)) {
855                 if (SSL_CTX_load_verify_locations(cfg->ssl_ctx, S_OR(cfg->cafile, NULL), S_OR(cfg->capath,NULL)) == 0) {
856                         ast_log(LOG_ERROR, "TLS/SSL CA file(%s)/path(%s) error\n", cfg->cafile, cfg->capath);
857                 }
858         }
859
860 #ifdef HAVE_OPENSSL_EC
861
862         if (!ast_strlen_zero(cfg->pvtfile)) {
863                 BIO *bio = BIO_new_file(cfg->pvtfile, "r");
864                 if (bio != NULL) {
865                         DH *dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
866                         if (dh != NULL) {
867                                 if (SSL_CTX_set_tmp_dh(cfg->ssl_ctx, dh)) {
868                                         long options = SSL_OP_CIPHER_SERVER_PREFERENCE | SSL_OP_SINGLE_DH_USE | SSL_OP_SINGLE_ECDH_USE;
869                                         options = SSL_CTX_set_options(cfg->ssl_ctx, options);
870                                         ast_verb(2, "TLS/SSL DH initialized, PFS cipher-suites enabled\n");
871                                 }
872                                 DH_free(dh);
873                         }
874                         BIO_free(bio);
875                 }
876         }
877         #ifndef SSL_CTRL_SET_ECDH_AUTO
878                 #define SSL_CTRL_SET_ECDH_AUTO 94
879         #endif
880         /* SSL_CTX_set_ecdh_auto(cfg->ssl_ctx, on); requires OpenSSL 1.0.2 which wraps: */
881         if (SSL_CTX_ctrl(cfg->ssl_ctx, SSL_CTRL_SET_ECDH_AUTO, 1, NULL)) {
882                 ast_verb(2, "TLS/SSL ECDH initialized (automatic), faster PFS ciphers enabled\n");
883         } else {
884                 /* enables AES-128 ciphers, to get AES-256 use NID_secp384r1 */
885                 EC_KEY *ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
886                 if (ecdh != NULL) {
887                         if (SSL_CTX_set_tmp_ecdh(cfg->ssl_ctx, ecdh)) {
888                                 ast_verb(2, "TLS/SSL ECDH initialized (secp256r1), faster PFS cipher-suites enabled\n");
889                         }
890                         EC_KEY_free(ecdh);
891                 }
892         }
893
894 #endif /* #ifdef HAVE_OPENSSL_EC */
895
896         ast_verb(2, "TLS/SSL certificate ok\n");        /* We should log which one that is ok. This message doesn't really make sense in production use */
897         return 1;
898 #endif
899 }
900
901 int ast_ssl_setup(struct ast_tls_config *cfg)
902 {
903         return __ssl_setup(cfg, 0);
904 }
905
906 void ast_ssl_teardown(struct ast_tls_config *cfg)
907 {
908 #ifdef DO_SSL
909         if (cfg->ssl_ctx) {
910                 SSL_CTX_free(cfg->ssl_ctx);
911                 cfg->ssl_ctx = NULL;
912         }
913 #endif
914 }
915
916 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct ast_tcptls_session_instance *tcptls_session)
917 {
918         struct ast_tcptls_session_args *desc;
919         int flags;
920
921         if (!(desc = tcptls_session->parent)) {
922                 goto client_start_error;
923         }
924
925         if (ast_connect(desc->accept_fd, &desc->remote_address)) {
926                 ast_log(LOG_ERROR, "Unable to connect %s to %s: %s\n",
927                         desc->name,
928                         ast_sockaddr_stringify(&desc->remote_address),
929                         strerror(errno));
930                 goto client_start_error;
931         }
932
933         flags = fcntl(desc->accept_fd, F_GETFL);
934         fcntl(desc->accept_fd, F_SETFL, flags & ~O_NONBLOCK);
935
936         if (desc->tls_cfg) {
937                 desc->tls_cfg->enabled = 1;
938                 __ssl_setup(desc->tls_cfg, 1);
939         }
940
941         return handle_tcptls_connection(tcptls_session);
942
943 client_start_error:
944         if (desc) {
945                 close(desc->accept_fd);
946                 desc->accept_fd = -1;
947         }
948         ao2_ref(tcptls_session, -1);
949         return NULL;
950
951 }
952
953 struct ast_tcptls_session_instance *ast_tcptls_client_create(struct ast_tcptls_session_args *desc)
954 {
955         int x = 1;
956         struct ast_tcptls_session_instance *tcptls_session = NULL;
957
958         /* Do nothing if nothing has changed */
959         if (!ast_sockaddr_cmp(&desc->old_address, &desc->remote_address)) {
960                 ast_debug(1, "Nothing changed in %s\n", desc->name);
961                 return NULL;
962         }
963
964         /* If we return early, there is no connection */
965         ast_sockaddr_setnull(&desc->old_address);
966
967         if (desc->accept_fd != -1) {
968                 close(desc->accept_fd);
969         }
970
971         desc->accept_fd = socket(ast_sockaddr_is_ipv6(&desc->remote_address) ?
972                                  AF_INET6 : AF_INET, SOCK_STREAM, IPPROTO_TCP);
973         if (desc->accept_fd < 0) {
974                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n",
975                         desc->name, strerror(errno));
976                 return NULL;
977         }
978
979         /* if a local address was specified, bind to it so the connection will
980            originate from the desired address */
981         if (!ast_sockaddr_isnull(&desc->local_address)) {
982                 setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
983                 if (ast_bind(desc->accept_fd, &desc->local_address)) {
984                         ast_log(LOG_ERROR, "Unable to bind %s to %s: %s\n",
985                                 desc->name,
986                                 ast_sockaddr_stringify(&desc->local_address),
987                                 strerror(errno));
988                         goto error;
989                 }
990         }
991
992         if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor))) {
993                 goto error;
994         }
995
996         tcptls_session->overflow_buf = ast_str_create(128);
997         tcptls_session->client = 1;
998         tcptls_session->fd = desc->accept_fd;
999         tcptls_session->parent = desc;
1000         tcptls_session->parent->worker_fn = NULL;
1001         ast_sockaddr_copy(&tcptls_session->remote_address,
1002                           &desc->remote_address);
1003
1004         /* Set current info */
1005         ast_sockaddr_copy(&desc->old_address, &desc->remote_address);
1006         return tcptls_session;
1007
1008 error:
1009         close(desc->accept_fd);
1010         desc->accept_fd = -1;
1011         if (tcptls_session) {
1012                 ao2_ref(tcptls_session, -1);
1013         }
1014         return NULL;
1015 }
1016
1017 void ast_tcptls_server_start(struct ast_tcptls_session_args *desc)
1018 {
1019         int flags;
1020         int x = 1;
1021
1022         /* Do nothing if nothing has changed */
1023         if (!ast_sockaddr_cmp(&desc->old_address, &desc->local_address)) {
1024                 ast_debug(1, "Nothing changed in %s\n", desc->name);
1025                 return;
1026         }
1027
1028         /* If we return early, there is no one listening */
1029         ast_sockaddr_setnull(&desc->old_address);
1030
1031         /* Shutdown a running server if there is one */
1032         if (desc->master != AST_PTHREADT_NULL) {
1033                 pthread_cancel(desc->master);
1034                 pthread_kill(desc->master, SIGURG);
1035                 pthread_join(desc->master, NULL);
1036         }
1037
1038         if (desc->accept_fd != -1) {
1039                 close(desc->accept_fd);
1040         }
1041
1042         /* If there's no new server, stop here */
1043         if (ast_sockaddr_isnull(&desc->local_address)) {
1044                 ast_debug(2, "Server disabled:  %s\n", desc->name);
1045                 return;
1046         }
1047
1048         desc->accept_fd = socket(ast_sockaddr_is_ipv6(&desc->local_address) ?
1049                                  AF_INET6 : AF_INET, SOCK_STREAM, 0);
1050         if (desc->accept_fd < 0) {
1051                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n", desc->name, strerror(errno));
1052                 return;
1053         }
1054
1055         setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
1056         if (ast_bind(desc->accept_fd, &desc->local_address)) {
1057                 ast_log(LOG_ERROR, "Unable to bind %s to %s: %s\n",
1058                         desc->name,
1059                         ast_sockaddr_stringify(&desc->local_address),
1060                         strerror(errno));
1061                 goto error;
1062         }
1063         if (listen(desc->accept_fd, 10)) {
1064                 ast_log(LOG_ERROR, "Unable to listen for %s!\n", desc->name);
1065                 goto error;
1066         }
1067         flags = fcntl(desc->accept_fd, F_GETFL);
1068         fcntl(desc->accept_fd, F_SETFL, flags | O_NONBLOCK);
1069         if (ast_pthread_create_background(&desc->master, NULL, desc->accept_fn, desc)) {
1070                 ast_log(LOG_ERROR, "Unable to launch thread for %s on %s: %s\n",
1071                         desc->name,
1072                         ast_sockaddr_stringify(&desc->local_address),
1073                         strerror(errno));
1074                 goto error;
1075         }
1076
1077         /* Set current info */
1078         ast_sockaddr_copy(&desc->old_address, &desc->local_address);
1079
1080         return;
1081
1082 error:
1083         close(desc->accept_fd);
1084         desc->accept_fd = -1;
1085 }
1086
1087 void ast_tcptls_close_session_file(struct ast_tcptls_session_instance *tcptls_session)
1088 {
1089         if (tcptls_session->f) {
1090                 fflush(tcptls_session->f);
1091                 if (fclose(tcptls_session->f)) {
1092                         ast_log(LOG_ERROR, "fclose() failed: %s\n", strerror(errno));
1093                 }
1094                 tcptls_session->f = NULL;
1095                 tcptls_session->fd = -1;
1096         } else if (tcptls_session->fd != -1) {
1097                 /*
1098                  * Issuing shutdown() is necessary here to avoid a race
1099                  * condition where the last data written may not appear
1100                  * in the TCP stream.  See ASTERISK-23548
1101                  */
1102                 shutdown(tcptls_session->fd, SHUT_RDWR);
1103                 if (close(tcptls_session->fd)) {
1104                         ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
1105                 }
1106                 tcptls_session->fd = -1;
1107         } else {
1108                 ast_log(LOG_ERROR, "ast_tcptls_close_session_file invoked on session instance without file or file descriptor\n");
1109         }
1110 }
1111
1112 void ast_tcptls_server_stop(struct ast_tcptls_session_args *desc)
1113 {
1114         if (desc->master != AST_PTHREADT_NULL) {
1115                 pthread_cancel(desc->master);
1116                 pthread_kill(desc->master, SIGURG);
1117                 pthread_join(desc->master, NULL);
1118                 desc->master = AST_PTHREADT_NULL;
1119         }
1120         if (desc->accept_fd != -1) {
1121                 close(desc->accept_fd);
1122         }
1123         desc->accept_fd = -1;
1124         ast_debug(2, "Stopped server :: %s\n", desc->name);
1125 }
1126
1127 int ast_tls_read_conf(struct ast_tls_config *tls_cfg, struct ast_tcptls_session_args *tls_desc, const char *varname, const char *value)
1128 {
1129         if (!strcasecmp(varname, "tlsenable") || !strcasecmp(varname, "sslenable")) {
1130                 tls_cfg->enabled = ast_true(value) ? 1 : 0;
1131         } else if (!strcasecmp(varname, "tlscertfile") || !strcasecmp(varname, "sslcert") || !strcasecmp(varname, "tlscert")) {
1132                 ast_free(tls_cfg->certfile);
1133                 tls_cfg->certfile = ast_strdup(value);
1134         } else if (!strcasecmp(varname, "tlsprivatekey") || !strcasecmp(varname, "sslprivatekey")) {
1135                 ast_free(tls_cfg->pvtfile);
1136                 tls_cfg->pvtfile = ast_strdup(value);
1137         } else if (!strcasecmp(varname, "tlscipher") || !strcasecmp(varname, "sslcipher")) {
1138                 ast_free(tls_cfg->cipher);
1139                 tls_cfg->cipher = ast_strdup(value);
1140         } else if (!strcasecmp(varname, "tlscafile")) {
1141                 ast_free(tls_cfg->cafile);
1142                 tls_cfg->cafile = ast_strdup(value);
1143         } else if (!strcasecmp(varname, "tlscapath") || !strcasecmp(varname, "tlscadir")) {
1144                 ast_free(tls_cfg->capath);
1145                 tls_cfg->capath = ast_strdup(value);
1146         } else if (!strcasecmp(varname, "tlsverifyclient")) {
1147                 ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_VERIFY_CLIENT);
1148         } else if (!strcasecmp(varname, "tlsdontverifyserver")) {
1149                 ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_DONT_VERIFY_SERVER);
1150         } else if (!strcasecmp(varname, "tlsbindaddr") || !strcasecmp(varname, "sslbindaddr")) {
1151                 if (ast_parse_arg(value, PARSE_ADDR, &tls_desc->local_address))
1152                         ast_log(LOG_ERROR, "Invalid %s '%s'\n", varname, value);
1153         } else if (!strcasecmp(varname, "tlsclientmethod") || !strcasecmp(varname, "sslclientmethod")) {
1154                 if (!strcasecmp(value, "tlsv1")) {
1155                         ast_set_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
1156                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
1157                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV2_CLIENT);
1158                 } else if (!strcasecmp(value, "sslv3")) {
1159                         ast_set_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
1160                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV2_CLIENT);
1161                         ast_clear_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
1162                 } else if (!strcasecmp(value, "sslv2")) {
1163                         ast_set_flag(&tls_cfg->flags, AST_SSL_SSLV2_CLIENT);
1164                         ast_clear_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
1165                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
1166                 }
1167         } else {
1168                 return -1;
1169         }
1170
1171         return 0;
1172 }