source: vendor/current/source4/lib/tls/tls.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 15.8 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 transport layer security handling code
5
6 Copyright (C) Andrew Tridgell 2004-2005
7 Copyright (C) Stefan Metzmacher 2004
8 Copyright (C) Andrew Bartlett 2006
9
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
14
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>.
22*/
23
24#include "includes.h"
25#include "system/filesys.h"
26#include "lib/events/events.h"
27#include "lib/socket/socket.h"
28#include "lib/tls/tls.h"
29#include "param/param.h"
30
31#if ENABLE_GNUTLS
32#include <gnutls/gnutls.h>
33
34#define DH_BITS 2048
35
36#if defined(HAVE_GNUTLS_DATUM) && !defined(HAVE_GNUTLS_DATUM_T)
37typedef gnutls_datum gnutls_datum_t;
38#endif
39
40/* hold persistent tls data */
41struct tls_params {
42 gnutls_certificate_credentials x509_cred;
43 gnutls_dh_params dh_params;
44 bool tls_enabled;
45 const char *tls_priority;
46};
47#endif
48
49/* hold per connection tls data */
50struct tls_context {
51 struct socket_context *socket;
52 struct tevent_fd *fde;
53 bool tls_enabled;
54#if ENABLE_GNUTLS
55 gnutls_session session;
56 bool done_handshake;
57 bool have_first_byte;
58 uint8_t first_byte;
59 bool tls_detect;
60 const char *plain_chars;
61 bool output_pending;
62 gnutls_certificate_credentials xcred;
63 bool interrupted;
64#endif
65};
66
67bool tls_enabled(struct socket_context *sock)
68{
69 struct tls_context *tls;
70 if (!sock) {
71 return false;
72 }
73 if (strcmp(sock->backend_name, "tls") != 0) {
74 return false;
75 }
76 tls = talloc_get_type(sock->private_data, struct tls_context);
77 if (!tls) {
78 return false;
79 }
80 return tls->tls_enabled;
81}
82
83
84#if ENABLE_GNUTLS
85
86static const struct socket_ops tls_socket_ops;
87
88static NTSTATUS tls_socket_init(struct socket_context *sock)
89{
90 switch (sock->type) {
91 case SOCKET_TYPE_STREAM:
92 break;
93 default:
94 return NT_STATUS_INVALID_PARAMETER;
95 }
96
97 sock->backend_name = "tls";
98
99 return NT_STATUS_OK;
100}
101
102#define TLSCHECK(call) do { \
103 ret = call; \
104 if (ret < 0) { \
105 DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \
106 goto failed; \
107 } \
108} while (0)
109
110
111/*
112 callback for reading from a socket
113*/
114static ssize_t tls_pull(gnutls_transport_ptr ptr, void *buf, size_t size)
115{
116 struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
117 NTSTATUS status;
118 size_t nread;
119
120 if (tls->have_first_byte) {
121 *(uint8_t *)buf = tls->first_byte;
122 tls->have_first_byte = false;
123 return 1;
124 }
125
126 status = socket_recv(tls->socket, buf, size, &nread);
127 if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
128 return 0;
129 }
130 if (NT_STATUS_IS_ERR(status)) {
131 TEVENT_FD_NOT_READABLE(tls->fde);
132 TEVENT_FD_NOT_WRITEABLE(tls->fde);
133 errno = EBADF;
134 return -1;
135 }
136 if (!NT_STATUS_IS_OK(status)) {
137 TEVENT_FD_READABLE(tls->fde);
138 errno = EAGAIN;
139 return -1;
140 }
141 if (tls->output_pending) {
142 TEVENT_FD_WRITEABLE(tls->fde);
143 }
144 if (size != nread) {
145 TEVENT_FD_READABLE(tls->fde);
146 }
147 return nread;
148}
149
150/*
151 callback for writing to a socket
152*/
153static ssize_t tls_push(gnutls_transport_ptr ptr, const void *buf, size_t size)
154{
155 struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
156 NTSTATUS status;
157 size_t nwritten, total_nwritten = 0;
158 DATA_BLOB b;
159
160 if (!tls->tls_enabled) {
161 return size;
162 }
163
164 b.data = discard_const(buf);
165 b.length = size;
166
167 /* Cope with socket_wrapper 1500 byte chunking for PCAP */
168 do {
169 status = socket_send(tls->socket, &b, &nwritten);
170
171 if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
172 errno = EAGAIN;
173 return -1;
174 }
175 if (!NT_STATUS_IS_OK(status)) {
176 TEVENT_FD_WRITEABLE(tls->fde);
177 return -1;
178 }
179
180 total_nwritten += nwritten;
181
182 if (size == nwritten) {
183 break;
184 }
185
186 b.data += nwritten;
187 b.length -= nwritten;
188
189 TEVENT_FD_WRITEABLE(tls->fde);
190 } while (b.length);
191
192 return total_nwritten;
193}
194
195/*
196 destroy a tls session
197 */
198static int tls_destructor(struct tls_context *tls)
199{
200 int ret;
201 ret = gnutls_bye(tls->session, GNUTLS_SHUT_WR);
202 if (ret < 0) {
203 DEBUG(4,("TLS gnutls_bye failed - %s\n", gnutls_strerror(ret)));
204 }
205 return 0;
206}
207
208
209/*
210 possibly continue the handshake process
211*/
212static NTSTATUS tls_handshake(struct tls_context *tls)
213{
214 int ret;
215
216 if (tls->done_handshake) {
217 return NT_STATUS_OK;
218 }
219
220 ret = gnutls_handshake(tls->session);
221 if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
222 if (gnutls_record_get_direction(tls->session) == 1) {
223 TEVENT_FD_WRITEABLE(tls->fde);
224 }
225 return STATUS_MORE_ENTRIES;
226 }
227 if (ret < 0) {
228 DEBUG(0,("TLS gnutls_handshake failed - %s\n", gnutls_strerror(ret)));
229 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
230 }
231 tls->done_handshake = true;
232 return NT_STATUS_OK;
233}
234
235/*
236 possibly continue an interrupted operation
237*/
238static NTSTATUS tls_interrupted(struct tls_context *tls)
239{
240 int ret;
241
242 if (!tls->interrupted) {
243 return NT_STATUS_OK;
244 }
245 if (gnutls_record_get_direction(tls->session) == 1) {
246 ret = gnutls_record_send(tls->session, NULL, 0);
247 } else {
248 ret = gnutls_record_recv(tls->session, NULL, 0);
249 }
250 if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
251 return STATUS_MORE_ENTRIES;
252 }
253 tls->interrupted = false;
254 return NT_STATUS_OK;
255}
256
257/*
258 see how many bytes are pending on the connection
259*/
260static NTSTATUS tls_socket_pending(struct socket_context *sock, size_t *npending)
261{
262 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
263 if (!tls->tls_enabled || tls->tls_detect) {
264 return socket_pending(tls->socket, npending);
265 }
266 *npending = gnutls_record_check_pending(tls->session);
267 if (*npending == 0) {
268 NTSTATUS status = socket_pending(tls->socket, npending);
269 if (*npending == 0) {
270 /* seems to be a gnutls bug */
271 (*npending) = 100;
272 }
273 return status;
274 }
275 return NT_STATUS_OK;
276}
277
278/*
279 receive data either by tls or normal socket_recv
280*/
281static NTSTATUS tls_socket_recv(struct socket_context *sock, void *buf,
282 size_t wantlen, size_t *nread)
283{
284 int ret;
285 NTSTATUS status;
286 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
287
288 if (tls->tls_enabled && tls->tls_detect) {
289 status = socket_recv(tls->socket, &tls->first_byte, 1, nread);
290 NT_STATUS_NOT_OK_RETURN(status);
291 if (*nread == 0) return NT_STATUS_OK;
292 tls->tls_detect = false;
293 /* look for the first byte of a valid HTTP operation */
294 if (strchr(tls->plain_chars, tls->first_byte)) {
295 /* not a tls link */
296 tls->tls_enabled = false;
297 *(uint8_t *)buf = tls->first_byte;
298 return NT_STATUS_OK;
299 }
300 tls->have_first_byte = true;
301 }
302
303 if (!tls->tls_enabled) {
304 return socket_recv(tls->socket, buf, wantlen, nread);
305 }
306
307 status = tls_handshake(tls);
308 NT_STATUS_NOT_OK_RETURN(status);
309
310 status = tls_interrupted(tls);
311 NT_STATUS_NOT_OK_RETURN(status);
312
313 ret = gnutls_record_recv(tls->session, buf, wantlen);
314 if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
315 if (gnutls_record_get_direction(tls->session) == 1) {
316 TEVENT_FD_WRITEABLE(tls->fde);
317 }
318 tls->interrupted = true;
319 return STATUS_MORE_ENTRIES;
320 }
321 if (ret < 0) {
322 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
323 }
324 *nread = ret;
325 return NT_STATUS_OK;
326}
327
328
329/*
330 send data either by tls or normal socket_recv
331*/
332static NTSTATUS tls_socket_send(struct socket_context *sock,
333 const DATA_BLOB *blob, size_t *sendlen)
334{
335 NTSTATUS status;
336 int ret;
337 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
338
339 if (!tls->tls_enabled) {
340 return socket_send(tls->socket, blob, sendlen);
341 }
342
343 status = tls_handshake(tls);
344 NT_STATUS_NOT_OK_RETURN(status);
345
346 status = tls_interrupted(tls);
347 NT_STATUS_NOT_OK_RETURN(status);
348
349 ret = gnutls_record_send(tls->session, blob->data, blob->length);
350 if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
351 if (gnutls_record_get_direction(tls->session) == 1) {
352 TEVENT_FD_WRITEABLE(tls->fde);
353 }
354 tls->interrupted = true;
355 return STATUS_MORE_ENTRIES;
356 }
357 if (ret < 0) {
358 DEBUG(0,("gnutls_record_send of %d failed - %s\n", (int)blob->length, gnutls_strerror(ret)));
359 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
360 }
361 *sendlen = ret;
362 tls->output_pending = (ret < blob->length);
363 return NT_STATUS_OK;
364}
365
366
367/*
368 initialise global tls state
369*/
370struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx, struct loadparm_context *lp_ctx)
371{
372 struct tls_params *params;
373 int ret;
374 struct stat st;
375 TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
376 const char *keyfile = lpcfg_tls_keyfile(tmp_ctx, lp_ctx);
377 const char *certfile = lpcfg_tls_certfile(tmp_ctx, lp_ctx);
378 const char *cafile = lpcfg_tls_cafile(tmp_ctx, lp_ctx);
379 const char *crlfile = lpcfg_tls_crlfile(tmp_ctx, lp_ctx);
380 const char *dhpfile = lpcfg_tls_dhpfile(tmp_ctx, lp_ctx);
381 void tls_cert_generate(TALLOC_CTX *, const char *, const char *, const char *, const char *);
382 params = talloc(mem_ctx, struct tls_params);
383 if (params == NULL) {
384 talloc_free(tmp_ctx);
385 return NULL;
386 }
387
388 if (!lpcfg_tls_enabled(lp_ctx) || keyfile == NULL || *keyfile == 0) {
389 params->tls_enabled = false;
390 talloc_free(tmp_ctx);
391 return params;
392 }
393
394 params->tls_priority = lpcfg_tls_priority(lp_ctx);
395
396 if (!file_exist(cafile)) {
397 char *hostname = talloc_asprintf(mem_ctx, "%s.%s",
398 lpcfg_netbios_name(lp_ctx),
399 lpcfg_dnsdomain(lp_ctx));
400 if (hostname == NULL) {
401 ret = GNUTLS_E_MEMORY_ERROR;
402 goto init_failed;
403 }
404 tls_cert_generate(params, hostname, keyfile, certfile, cafile);
405 talloc_free(hostname);
406 }
407
408 if (file_exist(keyfile) &&
409 !file_check_permissions(keyfile, geteuid(), 0600, &st))
410 {
411 DEBUG(0, ("Invalid permissions on TLS private key file '%s':\n"
412 "owner uid %u should be %u, mode 0%o should be 0%o\n"
413 "This is known as CVE-2013-4476.\n"
414 "Removing all tls .pem files will cause an "
415 "auto-regeneration with the correct permissions.\n",
416 keyfile,
417 (unsigned int)st.st_uid, geteuid(),
418 (unsigned int)(st.st_mode & 0777), 0600));
419 talloc_free(tmp_ctx);
420 return NULL;
421 }
422
423 ret = gnutls_global_init();
424 if (ret < 0) goto init_failed;
425
426 gnutls_certificate_allocate_credentials(&params->x509_cred);
427 if (ret < 0) goto init_failed;
428
429 if (cafile && *cafile) {
430 ret = gnutls_certificate_set_x509_trust_file(params->x509_cred, cafile,
431 GNUTLS_X509_FMT_PEM);
432 if (ret < 0) {
433 DEBUG(0,("TLS failed to initialise cafile %s\n", cafile));
434 goto init_failed;
435 }
436 }
437
438 if (crlfile && *crlfile) {
439 ret = gnutls_certificate_set_x509_crl_file(params->x509_cred,
440 crlfile,
441 GNUTLS_X509_FMT_PEM);
442 if (ret < 0) {
443 DEBUG(0,("TLS failed to initialise crlfile %s\n", crlfile));
444 goto init_failed;
445 }
446 }
447
448 ret = gnutls_certificate_set_x509_key_file(params->x509_cred,
449 certfile, keyfile,
450 GNUTLS_X509_FMT_PEM);
451 if (ret < 0) {
452 DEBUG(0,("TLS failed to initialise certfile %s and keyfile %s\n",
453 certfile, keyfile));
454 goto init_failed;
455 }
456
457 ret = gnutls_dh_params_init(&params->dh_params);
458 if (ret < 0) goto init_failed;
459
460 if (dhpfile && *dhpfile) {
461 gnutls_datum_t dhparms;
462 size_t size;
463 dhparms.data = (uint8_t *)file_load(dhpfile, &size, 0, mem_ctx);
464
465 if (!dhparms.data) {
466 DEBUG(0,("Failed to read DH Parms from %s\n", dhpfile));
467 goto init_failed;
468 }
469 dhparms.size = size;
470
471 ret = gnutls_dh_params_import_pkcs3(params->dh_params, &dhparms, GNUTLS_X509_FMT_PEM);
472 if (ret < 0) goto init_failed;
473 } else {
474 ret = gnutls_dh_params_generate2(params->dh_params, DH_BITS);
475 if (ret < 0) goto init_failed;
476 }
477
478 gnutls_certificate_set_dh_params(params->x509_cred, params->dh_params);
479
480 params->tls_enabled = true;
481
482 talloc_free(tmp_ctx);
483 return params;
484
485init_failed:
486 DEBUG(0,("GNUTLS failed to initialise - %s\n", gnutls_strerror(ret)));
487 params->tls_enabled = false;
488 talloc_free(tmp_ctx);
489 return params;
490}
491
492
493/*
494 setup for a new connection
495*/
496struct socket_context *tls_init_server(struct tls_params *params,
497 struct socket_context *socket_ctx,
498 struct tevent_fd *fde,
499 const char *plain_chars)
500{
501 struct tls_context *tls;
502 int ret;
503 struct socket_context *new_sock;
504 NTSTATUS nt_status;
505 const char *error_pos;
506
507 nt_status = socket_create_with_ops(socket_ctx, &tls_socket_ops, &new_sock,
508 SOCKET_TYPE_STREAM,
509 socket_ctx->flags | SOCKET_FLAG_ENCRYPT);
510 if (!NT_STATUS_IS_OK(nt_status)) {
511 return NULL;
512 }
513
514 tls = talloc(new_sock, struct tls_context);
515 if (tls == NULL) {
516 return NULL;
517 }
518
519 tls->socket = socket_ctx;
520 talloc_steal(tls, socket_ctx);
521 tls->fde = fde;
522
523 new_sock->private_data = tls;
524
525 if (!params->tls_enabled) {
526 talloc_free(new_sock);
527 return NULL;
528 }
529
530 TLSCHECK(gnutls_init(&tls->session, GNUTLS_SERVER));
531
532 talloc_set_destructor(tls, tls_destructor);
533
534 ret = gnutls_priority_set_direct(tls->session,
535 params->tls_priority,
536 &error_pos);
537 if (ret != GNUTLS_E_SUCCESS) {
538 DEBUG(0,("TLS %s - %s. Check 'tls priority' option at '%s'\n",
539 __location__, gnutls_strerror(ret), error_pos));
540 talloc_free(new_sock);
541 return NULL;
542 }
543
544 TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE,
545 params->x509_cred));
546 gnutls_certificate_server_set_request(tls->session, GNUTLS_CERT_REQUEST);
547 gnutls_dh_set_prime_bits(tls->session, DH_BITS);
548 gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
549 gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
550 gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
551#if GNUTLS_VERSION_MAJOR < 3
552 gnutls_transport_set_lowat(tls->session, 0);
553#endif
554
555 tls->plain_chars = plain_chars;
556 if (plain_chars) {
557 tls->tls_detect = true;
558 } else {
559 tls->tls_detect = false;
560 }
561
562 tls->output_pending = false;
563 tls->done_handshake = false;
564 tls->have_first_byte = false;
565 tls->tls_enabled = true;
566 tls->interrupted = false;
567
568 new_sock->state = SOCKET_STATE_SERVER_CONNECTED;
569
570 return new_sock;
571
572failed:
573 DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
574 talloc_free(new_sock);
575 return NULL;
576}
577
578
579static NTSTATUS tls_socket_set_option(struct socket_context *sock, const char *option, const char *val)
580{
581 set_socket_options(socket_get_fd(sock), option);
582 return NT_STATUS_OK;
583}
584
585static char *tls_socket_get_peer_name(struct socket_context *sock, TALLOC_CTX *mem_ctx)
586{
587 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
588 return socket_get_peer_name(tls->socket, mem_ctx);
589}
590
591static struct socket_address *tls_socket_get_peer_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
592{
593 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
594 return socket_get_peer_addr(tls->socket, mem_ctx);
595}
596
597static struct socket_address *tls_socket_get_my_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
598{
599 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
600 return socket_get_my_addr(tls->socket, mem_ctx);
601}
602
603static int tls_socket_get_fd(struct socket_context *sock)
604{
605 struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
606 return socket_get_fd(tls->socket);
607}
608
609static const struct socket_ops tls_socket_ops = {
610 .name = "tls",
611 .fn_init = tls_socket_init,
612 .fn_recv = tls_socket_recv,
613 .fn_send = tls_socket_send,
614 .fn_pending = tls_socket_pending,
615
616 .fn_set_option = tls_socket_set_option,
617
618 .fn_get_peer_name = tls_socket_get_peer_name,
619 .fn_get_peer_addr = tls_socket_get_peer_addr,
620 .fn_get_my_addr = tls_socket_get_my_addr,
621 .fn_get_fd = tls_socket_get_fd
622};
623
624#else
625
626/* for systems without tls we just fail the operations, and the caller
627 * will retain the original socket */
628
629struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx, struct loadparm_context *lp_ctx)
630{
631 return talloc_new(mem_ctx);
632}
633
634/*
635 setup for a new connection
636*/
637struct socket_context *tls_init_server(struct tls_params *params,
638 struct socket_context *socket,
639 struct tevent_fd *fde,
640 const char *plain_chars)
641{
642 return NULL;
643}
644
645
646#endif
647
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