Security/tcptls: MitM Attack potential from certificate with NULL byte in CN.
[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_FILE_VERSION(__FILE__, "$Revision$")
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                                 ERR_remove_state(0);
404                         }
405
406                         SSL_free(stream->ssl);
407                         stream->ssl = NULL;
408                 }
409 #endif  /* defined(DO_SSL) */
410
411                 /*
412                  * Issuing shutdown() is necessary here to avoid a race
413                  * condition where the last data written may not appear
414                  * in the TCP stream.  See ASTERISK-23548
415                  */
416                 shutdown(stream->fd, SHUT_RDWR);
417                 if (close(stream->fd)) {
418                         ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
419                 }
420                 stream->fd = -1;
421         }
422         ao2_t_ref(stream, -1, "Closed tcptls stream cookie");
423
424         return 0;
425 }
426
427 /*!
428  * \internal
429  * \brief fopencookie()/funopen() stream destructor function.
430  *
431  * \param cookie Stream control data.
432  *
433  * \return Nothing
434  */
435 static void tcptls_stream_dtor(void *cookie)
436 {
437 #ifdef AST_DEVMODE
438         /* Since the ast_assert below is the only one using stream,
439          * and ast_assert is only available with AST_DEVMODE, we
440          * put this in a conditional to avoid compiler warnings. */
441         struct ast_tcptls_stream *stream = cookie;
442 #endif
443
444         ast_assert(stream->fd == -1);
445 }
446
447 /*!
448  * \internal
449  * \brief fopencookie()/funopen() stream allocation function.
450  *
451  * \retval stream_cookie on success.
452  * \retval NULL on error.
453  */
454 static struct ast_tcptls_stream *tcptls_stream_alloc(void)
455 {
456         struct ast_tcptls_stream *stream;
457
458         stream = ao2_alloc_options(sizeof(*stream), tcptls_stream_dtor,
459                 AO2_ALLOC_OPT_LOCK_NOLOCK);
460         if (stream) {
461                 stream->fd = -1;
462                 stream->timeout = -1;
463         }
464         return stream;
465 }
466
467 /*!
468  * \internal
469  * \brief Open a custom FILE stream for tcptls.
470  *
471  * \param stream Stream cookie control data.
472  * \param ssl SSL state if not NULL.
473  * \param fd Socket file descriptor.
474  * \param timeout ms to wait for an event on fd. -1 if timeout disabled.
475  *
476  * \retval fp on success.
477  * \retval NULL on error.
478  */
479 static FILE *tcptls_stream_fopen(struct ast_tcptls_stream *stream, SSL *ssl, int fd, int timeout)
480 {
481         FILE *fp;
482
483 #if defined(HAVE_FOPENCOOKIE)   /* the glibc/linux interface */
484         static const cookie_io_functions_t cookie_funcs = {
485                 tcptls_stream_read,
486                 tcptls_stream_write,
487                 NULL,
488                 tcptls_stream_close
489         };
490 #endif  /* defined(HAVE_FOPENCOOKIE) */
491
492         if (fd == -1) {
493                 /* Socket not open. */
494                 return NULL;
495         }
496
497         stream->ssl = ssl;
498         stream->fd = fd;
499         stream->timeout = timeout;
500         ao2_t_ref(stream, +1, "Opening tcptls stream cookie");
501
502 #if defined(HAVE_FUNOPEN)       /* the BSD interface */
503         fp = funopen(stream, tcptls_stream_read, tcptls_stream_write, NULL,
504                 tcptls_stream_close);
505 #elif defined(HAVE_FOPENCOOKIE) /* the glibc/linux interface */
506         fp = fopencookie(stream, "w+", cookie_funcs);
507 #else
508         /* could add other methods here */
509         ast_debug(2, "No stream FILE methods attempted!\n");
510         fp = NULL;
511 #endif
512
513         if (!fp) {
514                 stream->fd = -1;
515                 ao2_t_ref(stream, -1, "Failed to open tcptls stream cookie");
516         }
517         return fp;
518 }
519
520 HOOK_T ast_tcptls_server_read(struct ast_tcptls_session_instance *tcptls_session, void *buf, size_t count)
521 {
522         if (!tcptls_session->stream_cookie || tcptls_session->stream_cookie->fd == -1) {
523                 ast_log(LOG_ERROR, "TCP/TLS read called on invalid stream.\n");
524                 errno = EIO;
525                 return -1;
526         }
527
528         return tcptls_stream_read(tcptls_session->stream_cookie, buf, count);
529 }
530
531 HOOK_T ast_tcptls_server_write(struct ast_tcptls_session_instance *tcptls_session, const void *buf, size_t count)
532 {
533         if (!tcptls_session->stream_cookie || tcptls_session->stream_cookie->fd == -1) {
534                 ast_log(LOG_ERROR, "TCP/TLS write called on invalid stream.\n");
535                 errno = EIO;
536                 return -1;
537         }
538
539         return tcptls_stream_write(tcptls_session->stream_cookie, buf, count);
540 }
541
542 static void session_instance_destructor(void *obj)
543 {
544         struct ast_tcptls_session_instance *i = obj;
545
546         if (i->stream_cookie) {
547                 ao2_t_ref(i->stream_cookie, -1, "Destroying tcptls session instance");
548                 i->stream_cookie = NULL;
549         }
550         ast_free(i->overflow_buf);
551         ao2_cleanup(i->private_data);
552 }
553
554 /*! \brief
555 * creates a FILE * from the fd passed by the accept thread.
556 * This operation is potentially expensive (certificate verification),
557 * so we do it in the child thread context.
558 *
559 * \note must decrement ref count before returning NULL on error
560 */
561 static void *handle_tcptls_connection(void *data)
562 {
563         struct ast_tcptls_session_instance *tcptls_session = data;
564 #ifdef DO_SSL
565         int (*ssl_setup)(SSL *) = (tcptls_session->client) ? SSL_connect : SSL_accept;
566         int ret;
567         char err[256];
568 #endif
569
570         /* TCP/TLS connections are associated with external protocols, and
571          * should not be allowed to execute 'dangerous' functions. This may
572          * need to be pushed down into the individual protocol handlers, but
573          * this seems like a good general policy.
574          */
575         if (ast_thread_inhibit_escalations()) {
576                 ast_log(LOG_ERROR, "Failed to inhibit privilege escalations; killing connection\n");
577                 ast_tcptls_close_session_file(tcptls_session);
578                 ao2_ref(tcptls_session, -1);
579                 return NULL;
580         }
581
582         tcptls_session->stream_cookie = tcptls_stream_alloc();
583         if (!tcptls_session->stream_cookie) {
584                 ast_tcptls_close_session_file(tcptls_session);
585                 ao2_ref(tcptls_session, -1);
586                 return NULL;
587         }
588
589         /*
590         * open a FILE * as appropriate.
591         */
592         if (!tcptls_session->parent->tls_cfg) {
593                 tcptls_session->f = tcptls_stream_fopen(tcptls_session->stream_cookie, NULL,
594                         tcptls_session->fd, -1);
595                 if (tcptls_session->f) {
596                         if (setvbuf(tcptls_session->f, NULL, _IONBF, 0)) {
597                                 ast_tcptls_close_session_file(tcptls_session);
598                         }
599                 }
600         }
601 #ifdef DO_SSL
602         else if ( (tcptls_session->ssl = SSL_new(tcptls_session->parent->tls_cfg->ssl_ctx)) ) {
603                 SSL_set_fd(tcptls_session->ssl, tcptls_session->fd);
604                 if ((ret = ssl_setup(tcptls_session->ssl)) <= 0) {
605                         ast_log(LOG_ERROR, "Problem setting up ssl connection: %s\n", ERR_error_string(ERR_get_error(), err));
606                 } else if ((tcptls_session->f = tcptls_stream_fopen(tcptls_session->stream_cookie,
607                         tcptls_session->ssl, tcptls_session->fd, -1))) {
608                         if ((tcptls_session->client && !ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_DONT_VERIFY_SERVER))
609                                 || (!tcptls_session->client && ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_VERIFY_CLIENT))) {
610                                 X509 *peer;
611                                 long res;
612                                 peer = SSL_get_peer_certificate(tcptls_session->ssl);
613                                 if (!peer) {
614                                         ast_log(LOG_ERROR, "No peer SSL certificate to verify\n");
615                                         ast_tcptls_close_session_file(tcptls_session);
616                                         ao2_ref(tcptls_session, -1);
617                                         return NULL;
618                                 }
619
620                                 res = SSL_get_verify_result(tcptls_session->ssl);
621                                 if (res != X509_V_OK) {
622                                         ast_log(LOG_ERROR, "Certificate did not verify: %s\n", X509_verify_cert_error_string(res));
623                                         X509_free(peer);
624                                         ast_tcptls_close_session_file(tcptls_session);
625                                         ao2_ref(tcptls_session, -1);
626                                         return NULL;
627                                 }
628                                 if (!ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_IGNORE_COMMON_NAME)) {
629                                         ASN1_STRING *str;
630                                         unsigned char *str2;
631                                         X509_NAME *name = X509_get_subject_name(peer);
632                                         int pos = -1;
633                                         int found = 0;
634
635                                         for (;;) {
636                                                 /* Walk the certificate to check all available "Common Name" */
637                                                 /* XXX Probably should do a gethostbyname on the hostname and compare that as well */
638                                                 pos = X509_NAME_get_index_by_NID(name, NID_commonName, pos);
639                                                 if (pos < 0) {
640                                                         break;
641                                                 }
642                                                 str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, pos));
643                                                 ret = ASN1_STRING_to_UTF8(&str2, str);
644                                                 if (ret < 0) {
645                                                         continue;
646                                                 }
647
648                                                 if (str2) {
649                                                         if (strlen((char *) str2) != ret) {
650                                                                 ast_log(LOG_WARNING, "Invalid certificate common name length (contains NULL bytes?)\n");
651                                                         } else if (!strcasecmp(tcptls_session->parent->hostname, (char *) str2)) {
652                                                                 found = 1;
653                                                         }
654                                                         ast_debug(3, "SSL Common Name compare s1='%s' s2='%s'\n", tcptls_session->parent->hostname, str2);
655                                                         OPENSSL_free(str2);
656                                                 }
657                                                 if (found) {
658                                                         break;
659                                                 }
660                                         }
661                                         if (!found) {
662                                                 ast_log(LOG_ERROR, "Certificate common name did not match (%s)\n", tcptls_session->parent->hostname);
663                                                 X509_free(peer);
664                                                 ast_tcptls_close_session_file(tcptls_session);
665                                                 ao2_ref(tcptls_session, -1);
666                                                 return NULL;
667                                         }
668                                 }
669                                 X509_free(peer);
670                         }
671                 }
672                 if (!tcptls_session->f) {       /* no success opening descriptor stacking */
673                         SSL_free(tcptls_session->ssl);
674                 }
675         }
676 #endif /* DO_SSL */
677
678         if (!tcptls_session->f) {
679                 ast_tcptls_close_session_file(tcptls_session);
680                 ast_log(LOG_WARNING, "FILE * open failed!\n");
681 #ifndef DO_SSL
682                 if (tcptls_session->parent->tls_cfg) {
683                         ast_log(LOG_ERROR, "Attempted a TLS connection without OpenSSL support. This will not work!\n");
684                 }
685 #endif
686                 ao2_ref(tcptls_session, -1);
687                 return NULL;
688         }
689
690         if (tcptls_session->parent->worker_fn) {
691                 return tcptls_session->parent->worker_fn(tcptls_session);
692         } else {
693                 return tcptls_session;
694         }
695 }
696
697 void *ast_tcptls_server_root(void *data)
698 {
699         struct ast_tcptls_session_args *desc = data;
700         int fd;
701         struct ast_sockaddr addr;
702         struct ast_tcptls_session_instance *tcptls_session;
703         pthread_t launched;
704
705         for (;;) {
706                 int i, flags;
707
708                 if (desc->periodic_fn) {
709                         desc->periodic_fn(desc);
710                 }
711                 i = ast_wait_for_input(desc->accept_fd, desc->poll_timeout);
712                 if (i <= 0) {
713                         continue;
714                 }
715                 fd = ast_accept(desc->accept_fd, &addr);
716                 if (fd < 0) {
717                         if ((errno != EAGAIN) && (errno != EWOULDBLOCK) && (errno != EINTR) && (errno != ECONNABORTED)) {
718                                 ast_log(LOG_ERROR, "Accept failed: %s\n", strerror(errno));
719                                 break;
720                         }
721                         continue;
722                 }
723                 tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor);
724                 if (!tcptls_session) {
725                         ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
726                         if (close(fd)) {
727                                 ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
728                         }
729                         continue;
730                 }
731
732                 tcptls_session->overflow_buf = ast_str_create(128);
733                 flags = fcntl(fd, F_GETFL);
734                 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
735                 tcptls_session->fd = fd;
736                 tcptls_session->parent = desc;
737                 ast_sockaddr_copy(&tcptls_session->remote_address, &addr);
738
739                 tcptls_session->client = 0;
740
741                 /* This thread is now the only place that controls the single ref to tcptls_session */
742                 if (ast_pthread_create_detached_background(&launched, NULL, handle_tcptls_connection, tcptls_session)) {
743                         ast_log(LOG_ERROR, "Unable to launch helper thread: %s\n", strerror(errno));
744                         ast_tcptls_close_session_file(tcptls_session);
745                         ao2_ref(tcptls_session, -1);
746                 }
747         }
748         return NULL;
749 }
750
751 static int __ssl_setup(struct ast_tls_config *cfg, int client)
752 {
753 #ifndef DO_SSL
754         cfg->enabled = 0;
755         return 0;
756 #else
757         int disable_ssl = 0;
758  
759         if (!cfg->enabled) {
760                 return 0;
761         }
762
763         /* Get rid of an old SSL_CTX since we're about to
764          * allocate a new one
765          */
766         if (cfg->ssl_ctx) {
767                 SSL_CTX_free(cfg->ssl_ctx);
768                 cfg->ssl_ctx = NULL;
769         }
770
771         if (client) {
772 #ifndef OPENSSL_NO_SSL2
773                 if (ast_test_flag(&cfg->flags, AST_SSL_SSLV2_CLIENT)) {
774                         ast_log(LOG_WARNING, "Usage of SSLv2 is discouraged due to known vulnerabilities. Please use 'tlsv1' or leave the TLS method unspecified!\n");
775                         cfg->ssl_ctx = SSL_CTX_new(SSLv2_client_method());
776                 } else
777 #endif
778 #ifndef OPENSSL_NO_SSL3_METHOD
779                 if (ast_test_flag(&cfg->flags, AST_SSL_SSLV3_CLIENT)) {
780                         ast_log(LOG_WARNING, "Usage of SSLv3 is discouraged due to known vulnerabilities. Please use 'tlsv1' or leave the TLS method unspecified!\n");
781                         cfg->ssl_ctx = SSL_CTX_new(SSLv3_client_method());
782                 } else
783 #endif
784                 if (ast_test_flag(&cfg->flags, AST_SSL_TLSV1_CLIENT)) {
785                         cfg->ssl_ctx = SSL_CTX_new(TLSv1_client_method());
786                 } else {
787                         disable_ssl = 1;
788                         cfg->ssl_ctx = SSL_CTX_new(SSLv23_client_method());
789                 }
790         } else {
791                 disable_ssl = 1;
792                 cfg->ssl_ctx = SSL_CTX_new(SSLv23_server_method());
793         }
794
795         if (!cfg->ssl_ctx) {
796                 ast_debug(1, "Sorry, SSL_CTX_new call returned null...\n");
797                 cfg->enabled = 0;
798                 return 0;
799         }
800
801         /* Due to the POODLE vulnerability, completely disable
802          * SSLv2 and SSLv3 if we are not explicitly told to use
803          * them. SSLv23_*_method supports TLSv1+.
804          */
805         if (disable_ssl) {
806                 long ssl_opts;
807
808                 ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
809                 SSL_CTX_set_options(cfg->ssl_ctx, ssl_opts);
810         }
811
812         SSL_CTX_set_verify(cfg->ssl_ctx,
813                 ast_test_flag(&cfg->flags, AST_SSL_VERIFY_CLIENT) ? SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT : SSL_VERIFY_NONE,
814                 NULL);
815
816         if (!ast_strlen_zero(cfg->certfile)) {
817                 char *tmpprivate = ast_strlen_zero(cfg->pvtfile) ? cfg->certfile : cfg->pvtfile;
818                 if (SSL_CTX_use_certificate_chain_file(cfg->ssl_ctx, cfg->certfile) == 0) {
819                         if (!client) {
820                                 /* Clients don't need a certificate, but if its setup we can use it */
821                                 ast_log(LOG_ERROR, "TLS/SSL error loading cert file. <%s>\n", cfg->certfile);
822                                 cfg->enabled = 0;
823                                 SSL_CTX_free(cfg->ssl_ctx);
824                                 cfg->ssl_ctx = NULL;
825                                 return 0;
826                         }
827                 }
828                 if ((SSL_CTX_use_PrivateKey_file(cfg->ssl_ctx, tmpprivate, SSL_FILETYPE_PEM) == 0) || (SSL_CTX_check_private_key(cfg->ssl_ctx) == 0 )) {
829                         if (!client) {
830                                 /* Clients don't need a private key, but if its setup we can use it */
831                                 ast_log(LOG_ERROR, "TLS/SSL error loading private key file. <%s>\n", tmpprivate);
832                                 cfg->enabled = 0;
833                                 SSL_CTX_free(cfg->ssl_ctx);
834                                 cfg->ssl_ctx = NULL;
835                                 return 0;
836                         }
837                 }
838         }
839         if (!ast_strlen_zero(cfg->cipher)) {
840                 if (SSL_CTX_set_cipher_list(cfg->ssl_ctx, cfg->cipher) == 0 ) {
841                         if (!client) {
842                                 ast_log(LOG_ERROR, "TLS/SSL cipher error <%s>\n", cfg->cipher);
843                                 cfg->enabled = 0;
844                                 SSL_CTX_free(cfg->ssl_ctx);
845                                 cfg->ssl_ctx = NULL;
846                                 return 0;
847                         }
848                 }
849         }
850         if (!ast_strlen_zero(cfg->cafile) || !ast_strlen_zero(cfg->capath)) {
851                 if (SSL_CTX_load_verify_locations(cfg->ssl_ctx, S_OR(cfg->cafile, NULL), S_OR(cfg->capath,NULL)) == 0) {
852                         ast_log(LOG_ERROR, "TLS/SSL CA file(%s)/path(%s) error\n", cfg->cafile, cfg->capath);
853                 }
854         }
855
856 #ifdef HAVE_OPENSSL_EC
857
858         if (!ast_strlen_zero(cfg->pvtfile)) {
859                 BIO *bio = BIO_new_file(cfg->pvtfile, "r");
860                 if (bio != NULL) {
861                         DH *dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
862                         if (dh != NULL) {
863                                 if (SSL_CTX_set_tmp_dh(cfg->ssl_ctx, dh)) {
864                                         long options = SSL_OP_CIPHER_SERVER_PREFERENCE | SSL_OP_SINGLE_DH_USE | SSL_OP_SINGLE_ECDH_USE;
865                                         options = SSL_CTX_set_options(cfg->ssl_ctx, options);
866                                         ast_verb(2, "TLS/SSL DH initialized, PFS cipher-suites enabled\n");
867                                 }
868                                 DH_free(dh);
869                         }
870                         BIO_free(bio);
871                 }
872         }
873         #ifndef SSL_CTRL_SET_ECDH_AUTO
874                 #define SSL_CTRL_SET_ECDH_AUTO 94
875         #endif
876         /* SSL_CTX_set_ecdh_auto(cfg->ssl_ctx, on); requires OpenSSL 1.0.2 which wraps: */
877         if (SSL_CTX_ctrl(cfg->ssl_ctx, SSL_CTRL_SET_ECDH_AUTO, 1, NULL)) {
878                 ast_verb(2, "TLS/SSL ECDH initialized (automatic), faster PFS ciphers enabled\n");
879         } else {
880                 /* enables AES-128 ciphers, to get AES-256 use NID_secp384r1 */
881                 EC_KEY *ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
882                 if (ecdh != NULL) {
883                         if (SSL_CTX_set_tmp_ecdh(cfg->ssl_ctx, ecdh)) {
884                                 ast_verb(2, "TLS/SSL ECDH initialized (secp256r1), faster PFS cipher-suites enabled\n");
885                         }
886                         EC_KEY_free(ecdh);
887                 }
888         }
889
890 #endif /* #ifdef HAVE_OPENSSL_EC */
891
892         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 */
893         return 1;
894 #endif
895 }
896
897 int ast_ssl_setup(struct ast_tls_config *cfg)
898 {
899         return __ssl_setup(cfg, 0);
900 }
901
902 void ast_ssl_teardown(struct ast_tls_config *cfg)
903 {
904 #ifdef DO_SSL
905         if (cfg->ssl_ctx) {
906                 SSL_CTX_free(cfg->ssl_ctx);
907                 cfg->ssl_ctx = NULL;
908         }
909 #endif
910 }
911
912 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct ast_tcptls_session_instance *tcptls_session)
913 {
914         struct ast_tcptls_session_args *desc;
915         int flags;
916
917         if (!(desc = tcptls_session->parent)) {
918                 goto client_start_error;
919         }
920
921         if (ast_connect(desc->accept_fd, &desc->remote_address)) {
922                 ast_log(LOG_ERROR, "Unable to connect %s to %s: %s\n",
923                         desc->name,
924                         ast_sockaddr_stringify(&desc->remote_address),
925                         strerror(errno));
926                 goto client_start_error;
927         }
928
929         flags = fcntl(desc->accept_fd, F_GETFL);
930         fcntl(desc->accept_fd, F_SETFL, flags & ~O_NONBLOCK);
931
932         if (desc->tls_cfg) {
933                 desc->tls_cfg->enabled = 1;
934                 __ssl_setup(desc->tls_cfg, 1);
935         }
936
937         return handle_tcptls_connection(tcptls_session);
938
939 client_start_error:
940         if (desc) {
941                 close(desc->accept_fd);
942                 desc->accept_fd = -1;
943         }
944         ao2_ref(tcptls_session, -1);
945         return NULL;
946
947 }
948
949 struct ast_tcptls_session_instance *ast_tcptls_client_create(struct ast_tcptls_session_args *desc)
950 {
951         int x = 1;
952         struct ast_tcptls_session_instance *tcptls_session = NULL;
953
954         /* Do nothing if nothing has changed */
955         if (!ast_sockaddr_cmp(&desc->old_address, &desc->remote_address)) {
956                 ast_debug(1, "Nothing changed in %s\n", desc->name);
957                 return NULL;
958         }
959
960         /* If we return early, there is no connection */
961         ast_sockaddr_setnull(&desc->old_address);
962
963         if (desc->accept_fd != -1) {
964                 close(desc->accept_fd);
965         }
966
967         desc->accept_fd = socket(ast_sockaddr_is_ipv6(&desc->remote_address) ?
968                                  AF_INET6 : AF_INET, SOCK_STREAM, IPPROTO_TCP);
969         if (desc->accept_fd < 0) {
970                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n",
971                         desc->name, strerror(errno));
972                 return NULL;
973         }
974
975         /* if a local address was specified, bind to it so the connection will
976            originate from the desired address */
977         if (!ast_sockaddr_isnull(&desc->local_address)) {
978                 setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
979                 if (ast_bind(desc->accept_fd, &desc->local_address)) {
980                         ast_log(LOG_ERROR, "Unable to bind %s to %s: %s\n",
981                                 desc->name,
982                                 ast_sockaddr_stringify(&desc->local_address),
983                                 strerror(errno));
984                         goto error;
985                 }
986         }
987
988         if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor))) {
989                 goto error;
990         }
991
992         tcptls_session->overflow_buf = ast_str_create(128);
993         tcptls_session->client = 1;
994         tcptls_session->fd = desc->accept_fd;
995         tcptls_session->parent = desc;
996         tcptls_session->parent->worker_fn = NULL;
997         ast_sockaddr_copy(&tcptls_session->remote_address,
998                           &desc->remote_address);
999
1000         /* Set current info */
1001         ast_sockaddr_copy(&desc->old_address, &desc->remote_address);
1002         return tcptls_session;
1003
1004 error:
1005         close(desc->accept_fd);
1006         desc->accept_fd = -1;
1007         if (tcptls_session) {
1008                 ao2_ref(tcptls_session, -1);
1009         }
1010         return NULL;
1011 }
1012
1013 void ast_tcptls_server_start(struct ast_tcptls_session_args *desc)
1014 {
1015         int flags;
1016         int x = 1;
1017
1018         /* Do nothing if nothing has changed */
1019         if (!ast_sockaddr_cmp(&desc->old_address, &desc->local_address)) {
1020                 ast_debug(1, "Nothing changed in %s\n", desc->name);
1021                 return;
1022         }
1023
1024         /* If we return early, there is no one listening */
1025         ast_sockaddr_setnull(&desc->old_address);
1026
1027         /* Shutdown a running server if there is one */
1028         if (desc->master != AST_PTHREADT_NULL) {
1029                 pthread_cancel(desc->master);
1030                 pthread_kill(desc->master, SIGURG);
1031                 pthread_join(desc->master, NULL);
1032         }
1033
1034         if (desc->accept_fd != -1) {
1035                 close(desc->accept_fd);
1036         }
1037
1038         /* If there's no new server, stop here */
1039         if (ast_sockaddr_isnull(&desc->local_address)) {
1040                 ast_debug(2, "Server disabled:  %s\n", desc->name);
1041                 return;
1042         }
1043
1044         desc->accept_fd = socket(ast_sockaddr_is_ipv6(&desc->local_address) ?
1045                                  AF_INET6 : AF_INET, SOCK_STREAM, 0);
1046         if (desc->accept_fd < 0) {
1047                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n", desc->name, strerror(errno));
1048                 return;
1049         }
1050
1051         setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
1052         if (ast_bind(desc->accept_fd, &desc->local_address)) {
1053                 ast_log(LOG_ERROR, "Unable to bind %s to %s: %s\n",
1054                         desc->name,
1055                         ast_sockaddr_stringify(&desc->local_address),
1056                         strerror(errno));
1057                 goto error;
1058         }
1059         if (listen(desc->accept_fd, 10)) {
1060                 ast_log(LOG_ERROR, "Unable to listen for %s!\n", desc->name);
1061                 goto error;
1062         }
1063         flags = fcntl(desc->accept_fd, F_GETFL);
1064         fcntl(desc->accept_fd, F_SETFL, flags | O_NONBLOCK);
1065         if (ast_pthread_create_background(&desc->master, NULL, desc->accept_fn, desc)) {
1066                 ast_log(LOG_ERROR, "Unable to launch thread for %s on %s: %s\n",
1067                         desc->name,
1068                         ast_sockaddr_stringify(&desc->local_address),
1069                         strerror(errno));
1070                 goto error;
1071         }
1072
1073         /* Set current info */
1074         ast_sockaddr_copy(&desc->old_address, &desc->local_address);
1075
1076         return;
1077
1078 error:
1079         close(desc->accept_fd);
1080         desc->accept_fd = -1;
1081 }
1082
1083 void ast_tcptls_close_session_file(struct ast_tcptls_session_instance *tcptls_session)
1084 {
1085         if (tcptls_session->f) {
1086                 fflush(tcptls_session->f);
1087                 if (fclose(tcptls_session->f)) {
1088                         ast_log(LOG_ERROR, "fclose() failed: %s\n", strerror(errno));
1089                 }
1090                 tcptls_session->f = NULL;
1091                 tcptls_session->fd = -1;
1092         } else if (tcptls_session->fd != -1) {
1093                 /*
1094                  * Issuing shutdown() is necessary here to avoid a race
1095                  * condition where the last data written may not appear
1096                  * in the TCP stream.  See ASTERISK-23548
1097                  */
1098                 shutdown(tcptls_session->fd, SHUT_RDWR);
1099                 if (close(tcptls_session->fd)) {
1100                         ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
1101                 }
1102                 tcptls_session->fd = -1;
1103         } else {
1104                 ast_log(LOG_ERROR, "ast_tcptls_close_session_file invoked on session instance without file or file descriptor\n");
1105         }
1106 }
1107
1108 void ast_tcptls_server_stop(struct ast_tcptls_session_args *desc)
1109 {
1110         if (desc->master != AST_PTHREADT_NULL) {
1111                 pthread_cancel(desc->master);
1112                 pthread_kill(desc->master, SIGURG);
1113                 pthread_join(desc->master, NULL);
1114                 desc->master = AST_PTHREADT_NULL;
1115         }
1116         if (desc->accept_fd != -1) {
1117                 close(desc->accept_fd);
1118         }
1119         desc->accept_fd = -1;
1120         ast_debug(2, "Stopped server :: %s\n", desc->name);
1121 }
1122
1123 int ast_tls_read_conf(struct ast_tls_config *tls_cfg, struct ast_tcptls_session_args *tls_desc, const char *varname, const char *value)
1124 {
1125         if (!strcasecmp(varname, "tlsenable") || !strcasecmp(varname, "sslenable")) {
1126                 tls_cfg->enabled = ast_true(value) ? 1 : 0;
1127         } else if (!strcasecmp(varname, "tlscertfile") || !strcasecmp(varname, "sslcert") || !strcasecmp(varname, "tlscert")) {
1128                 ast_free(tls_cfg->certfile);
1129                 tls_cfg->certfile = ast_strdup(value);
1130         } else if (!strcasecmp(varname, "tlsprivatekey") || !strcasecmp(varname, "sslprivatekey")) {
1131                 ast_free(tls_cfg->pvtfile);
1132                 tls_cfg->pvtfile = ast_strdup(value);
1133         } else if (!strcasecmp(varname, "tlscipher") || !strcasecmp(varname, "sslcipher")) {
1134                 ast_free(tls_cfg->cipher);
1135                 tls_cfg->cipher = ast_strdup(value);
1136         } else if (!strcasecmp(varname, "tlscafile")) {
1137                 ast_free(tls_cfg->cafile);
1138                 tls_cfg->cafile = ast_strdup(value);
1139         } else if (!strcasecmp(varname, "tlscapath") || !strcasecmp(varname, "tlscadir")) {
1140                 ast_free(tls_cfg->capath);
1141                 tls_cfg->capath = ast_strdup(value);
1142         } else if (!strcasecmp(varname, "tlsverifyclient")) {
1143                 ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_VERIFY_CLIENT);
1144         } else if (!strcasecmp(varname, "tlsdontverifyserver")) {
1145                 ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_DONT_VERIFY_SERVER);
1146         } else if (!strcasecmp(varname, "tlsbindaddr") || !strcasecmp(varname, "sslbindaddr")) {
1147                 if (ast_parse_arg(value, PARSE_ADDR, &tls_desc->local_address))
1148                         ast_log(LOG_ERROR, "Invalid %s '%s'\n", varname, value);
1149         } else if (!strcasecmp(varname, "tlsclientmethod") || !strcasecmp(varname, "sslclientmethod")) {
1150                 if (!strcasecmp(value, "tlsv1")) {
1151                         ast_set_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
1152                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
1153                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV2_CLIENT);
1154                 } else if (!strcasecmp(value, "sslv3")) {
1155                         ast_set_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
1156                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV2_CLIENT);
1157                         ast_clear_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
1158                 } else if (!strcasecmp(value, "sslv2")) {
1159                         ast_set_flag(&tls_cfg->flags, AST_SSL_SSLV2_CLIENT);
1160                         ast_clear_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
1161                         ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
1162                 }
1163         } else {
1164                 return -1;
1165         }
1166
1167         return 0;
1168 }