r25446: Merge some changes I made on the way home from SFO:
[jelmer/samba4-debian.git] / source / lib / tls / tls.c
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 "lib/events/events.h"
26 #include "lib/socket/socket.h"
27 #include "lib/tls/tls.h"
28 #include "param/param.h"
29
30 #if ENABLE_GNUTLS
31 #include "gnutls/gnutls.h"
32
33 #define DH_BITS 1024
34
35 #if defined(HAVE_GNUTLS_DATUM) && !defined(HAVE_GNUTLS_DATUM_T)
36 typedef gnutls_datum gnutls_datum_t;
37 #endif
38
39 /* hold persistent tls data */
40 struct tls_params {
41         gnutls_certificate_credentials x509_cred;
42         gnutls_dh_params dh_params;
43         BOOL tls_enabled;
44 };
45 #endif
46
47 /* hold per connection tls data */
48 struct tls_context {
49         struct socket_context *socket;
50         struct fd_event *fde;
51         BOOL tls_enabled;
52 #if ENABLE_GNUTLS
53         gnutls_session session;
54         BOOL done_handshake;
55         BOOL have_first_byte;
56         uint8_t first_byte;
57         BOOL tls_detect;
58         const char *plain_chars;
59         BOOL output_pending;
60         gnutls_certificate_credentials xcred;
61         BOOL interrupted;
62 #endif
63 };
64
65 BOOL tls_enabled(struct socket_context *sock)
66 {
67         struct tls_context *tls;
68         if (!sock) {
69                 return False;
70         }
71         if (strcmp(sock->backend_name, "tls") != 0) {
72                 return False;
73         }
74         tls = talloc_get_type(sock->private_data, struct tls_context);
75         if (!tls) {
76                 return False;
77         }
78         return tls->tls_enabled;
79 }
80
81
82 #if ENABLE_GNUTLS
83
84 static const struct socket_ops tls_socket_ops;
85
86 static NTSTATUS tls_socket_init(struct socket_context *sock)
87 {
88         switch (sock->type) {
89         case SOCKET_TYPE_STREAM:
90                 break;
91         default:
92                 return NT_STATUS_INVALID_PARAMETER;
93         }
94
95         sock->backend_name = "tls";
96
97         return NT_STATUS_OK;
98 }
99
100 #define TLSCHECK(call) do { \
101         ret = call; \
102         if (ret < 0) { \
103                 DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \
104                 goto failed; \
105         } \
106 } while (0)
107
108
109 /*
110   callback for reading from a socket
111 */
112 static ssize_t tls_pull(gnutls_transport_ptr ptr, void *buf, size_t size)
113 {
114         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
115         NTSTATUS status;
116         size_t nread;
117         
118         if (tls->have_first_byte) {
119                 *(uint8_t *)buf = tls->first_byte;
120                 tls->have_first_byte = False;
121                 return 1;
122         }
123
124         status = socket_recv(tls->socket, buf, size, &nread);
125         if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
126                 return 0;
127         }
128         if (NT_STATUS_IS_ERR(status)) {
129                 EVENT_FD_NOT_READABLE(tls->fde);
130                 EVENT_FD_NOT_WRITEABLE(tls->fde);
131                 errno = EBADF;
132                 return -1;
133         }
134         if (!NT_STATUS_IS_OK(status)) {
135                 EVENT_FD_READABLE(tls->fde);
136                 errno = EAGAIN;
137                 return -1;
138         }
139         if (tls->output_pending) {
140                 EVENT_FD_WRITEABLE(tls->fde);
141         }
142         if (size != nread) {
143                 EVENT_FD_READABLE(tls->fde);
144         }
145         return nread;
146 }
147
148 /*
149   callback for writing to a socket
150 */
151 static ssize_t tls_push(gnutls_transport_ptr ptr, const void *buf, size_t size)
152 {
153         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
154         NTSTATUS status;
155         size_t nwritten;
156         DATA_BLOB b;
157
158         if (!tls->tls_enabled) {
159                 return size;
160         }
161
162         b.data = discard_const(buf);
163         b.length = size;
164
165         status = socket_send(tls->socket, &b, &nwritten);
166         if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
167                 errno = EAGAIN;
168                 return -1;
169         }
170         if (!NT_STATUS_IS_OK(status)) {
171                 EVENT_FD_WRITEABLE(tls->fde);
172                 return -1;
173         }
174         if (size != nwritten) {
175                 EVENT_FD_WRITEABLE(tls->fde);
176         }
177         return nwritten;
178 }
179
180 /*
181   destroy a tls session
182  */
183 static int tls_destructor(struct tls_context *tls)
184 {
185         int ret;
186         ret = gnutls_bye(tls->session, GNUTLS_SHUT_WR);
187         if (ret < 0) {
188                 DEBUG(0,("TLS gnutls_bye failed - %s\n", gnutls_strerror(ret)));
189         }
190         return 0;
191 }
192
193
194 /*
195   possibly continue the handshake process
196 */
197 static NTSTATUS tls_handshake(struct tls_context *tls)
198 {
199         int ret;
200
201         if (tls->done_handshake) {
202                 return NT_STATUS_OK;
203         }
204         
205         ret = gnutls_handshake(tls->session);
206         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
207                 if (gnutls_record_get_direction(tls->session) == 1) {
208                         EVENT_FD_WRITEABLE(tls->fde);
209                 }
210                 return STATUS_MORE_ENTRIES;
211         }
212         if (ret < 0) {
213                 DEBUG(0,("TLS gnutls_handshake failed - %s\n", gnutls_strerror(ret)));
214                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
215         }
216         tls->done_handshake = True;
217         return NT_STATUS_OK;
218 }
219
220 /*
221   possibly continue an interrupted operation
222 */
223 static NTSTATUS tls_interrupted(struct tls_context *tls)
224 {
225         int ret;
226
227         if (!tls->interrupted) {
228                 return NT_STATUS_OK;
229         }
230         if (gnutls_record_get_direction(tls->session) == 1) {
231                 ret = gnutls_record_send(tls->session, NULL, 0);
232         } else {
233                 ret = gnutls_record_recv(tls->session, NULL, 0);
234         }
235         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
236                 return STATUS_MORE_ENTRIES;
237         }
238         tls->interrupted = False;
239         return NT_STATUS_OK;
240 }
241
242 /*
243   see how many bytes are pending on the connection
244 */
245 static NTSTATUS tls_socket_pending(struct socket_context *sock, size_t *npending)
246 {
247         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
248         if (!tls->tls_enabled || tls->tls_detect) {
249                 return socket_pending(tls->socket, npending);
250         }
251         *npending = gnutls_record_check_pending(tls->session);
252         if (*npending == 0) {
253                 NTSTATUS status = socket_pending(tls->socket, npending);
254                 if (*npending == 0) {
255                         /* seems to be a gnutls bug */
256                         (*npending) = 100;
257                 }
258                 return status;
259         }
260         return NT_STATUS_OK;
261 }
262
263 /*
264   receive data either by tls or normal socket_recv
265 */
266 static NTSTATUS tls_socket_recv(struct socket_context *sock, void *buf, 
267                                 size_t wantlen, size_t *nread)
268 {
269         int ret;
270         NTSTATUS status;
271         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
272
273         if (tls->tls_enabled && tls->tls_detect) {
274                 status = socket_recv(tls->socket, &tls->first_byte, 1, nread);
275                 NT_STATUS_NOT_OK_RETURN(status);
276                 if (*nread == 0) return NT_STATUS_OK;
277                 tls->tls_detect = False;
278                 /* look for the first byte of a valid HTTP operation */
279                 if (strchr(tls->plain_chars, tls->first_byte)) {
280                         /* not a tls link */
281                         tls->tls_enabled = False;
282                         *(uint8_t *)buf = tls->first_byte;
283                         return NT_STATUS_OK;
284                 }
285                 tls->have_first_byte = True;
286         }
287
288         if (!tls->tls_enabled) {
289                 return socket_recv(tls->socket, buf, wantlen, nread);
290         }
291
292         status = tls_handshake(tls);
293         NT_STATUS_NOT_OK_RETURN(status);
294
295         status = tls_interrupted(tls);
296         NT_STATUS_NOT_OK_RETURN(status);
297
298         ret = gnutls_record_recv(tls->session, buf, wantlen);
299         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
300                 if (gnutls_record_get_direction(tls->session) == 1) {
301                         EVENT_FD_WRITEABLE(tls->fde);
302                 }
303                 tls->interrupted = True;
304                 return STATUS_MORE_ENTRIES;
305         }
306         if (ret < 0) {
307                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
308         }
309         *nread = ret;
310         return NT_STATUS_OK;
311 }
312
313
314 /*
315   send data either by tls or normal socket_recv
316 */
317 static NTSTATUS tls_socket_send(struct socket_context *sock, 
318                                 const DATA_BLOB *blob, size_t *sendlen)
319 {
320         NTSTATUS status;
321         int ret;
322         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
323
324         if (!tls->tls_enabled) {
325                 return socket_send(tls->socket, blob, sendlen);
326         }
327
328         status = tls_handshake(tls);
329         NT_STATUS_NOT_OK_RETURN(status);
330
331         status = tls_interrupted(tls);
332         NT_STATUS_NOT_OK_RETURN(status);
333
334         ret = gnutls_record_send(tls->session, blob->data, blob->length);
335         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
336                 if (gnutls_record_get_direction(tls->session) == 1) {
337                         EVENT_FD_WRITEABLE(tls->fde);
338                 }
339                 tls->interrupted = True;
340                 return STATUS_MORE_ENTRIES;
341         }
342         if (ret < 0) {
343                 DEBUG(0,("gnutls_record_send of %d failed - %s\n", (int)blob->length, gnutls_strerror(ret)));
344                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
345         }
346         *sendlen = ret;
347         tls->output_pending = (ret < blob->length);
348         return NT_STATUS_OK;
349 }
350
351
352 /*
353   initialise global tls state
354 */
355 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
356 {
357         struct tls_params *params;
358         int ret;
359         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
360         const char *keyfile = private_path(tmp_ctx, global_loadparm, lp_tls_keyfile(global_loadparm));
361         const char *certfile = private_path(tmp_ctx, global_loadparm, lp_tls_certfile(global_loadparm));
362         const char *cafile = private_path(tmp_ctx, global_loadparm, lp_tls_cafile(global_loadparm));
363         const char *crlfile = private_path(tmp_ctx, global_loadparm, lp_tls_crlfile(global_loadparm));
364         const char *dhpfile = private_path(tmp_ctx, global_loadparm, lp_tls_dhpfile(global_loadparm));
365         void tls_cert_generate(TALLOC_CTX *, const char *, const char *, const char *);
366
367         params = talloc(mem_ctx, struct tls_params);
368         if (params == NULL) {
369                 talloc_free(tmp_ctx);
370                 return NULL;
371         }
372
373         if (!lp_tls_enabled(global_loadparm) || keyfile == NULL || *keyfile == 0) {
374                 params->tls_enabled = False;
375                 talloc_free(tmp_ctx);
376                 return params;
377         }
378
379         if (!file_exist(cafile)) {
380                 tls_cert_generate(params, keyfile, certfile, cafile);
381         }
382
383         ret = gnutls_global_init();
384         if (ret < 0) goto init_failed;
385
386         gnutls_certificate_allocate_credentials(&params->x509_cred);
387         if (ret < 0) goto init_failed;
388
389         if (cafile && *cafile) {
390                 ret = gnutls_certificate_set_x509_trust_file(params->x509_cred, cafile, 
391                                                              GNUTLS_X509_FMT_PEM);      
392                 if (ret < 0) {
393                         DEBUG(0,("TLS failed to initialise cafile %s\n", cafile));
394                         goto init_failed;
395                 }
396         }
397
398         if (crlfile && *crlfile) {
399                 ret = gnutls_certificate_set_x509_crl_file(params->x509_cred, 
400                                                            crlfile, 
401                                                            GNUTLS_X509_FMT_PEM);
402                 if (ret < 0) {
403                         DEBUG(0,("TLS failed to initialise crlfile %s\n", crlfile));
404                         goto init_failed;
405                 }
406         }
407         
408         ret = gnutls_certificate_set_x509_key_file(params->x509_cred, 
409                                                    certfile, keyfile,
410                                                    GNUTLS_X509_FMT_PEM);
411         if (ret < 0) {
412                 DEBUG(0,("TLS failed to initialise certfile %s and keyfile %s\n", 
413                          certfile, keyfile));
414                 goto init_failed;
415         }
416         
417         
418         ret = gnutls_dh_params_init(&params->dh_params);
419         if (ret < 0) goto init_failed;
420
421         if (dhpfile && *dhpfile) {
422                 gnutls_datum_t dhparms;
423                 size_t size;
424                 dhparms.data = (uint8_t *)file_load(dhpfile, &size, mem_ctx);
425
426                 if (!dhparms.data) {
427                         DEBUG(0,("Failed to read DH Parms from %s\n", dhpfile));
428                         goto init_failed;
429                 }
430                 dhparms.size = size;
431                         
432                 ret = gnutls_dh_params_import_pkcs3(params->dh_params, &dhparms, GNUTLS_X509_FMT_PEM);
433                 if (ret < 0) goto init_failed;
434         } else {
435                 ret = gnutls_dh_params_generate2(params->dh_params, DH_BITS);
436                 if (ret < 0) goto init_failed;
437         }
438                 
439         gnutls_certificate_set_dh_params(params->x509_cred, params->dh_params);
440
441         params->tls_enabled = True;
442
443         talloc_free(tmp_ctx);
444         return params;
445
446 init_failed:
447         DEBUG(0,("GNUTLS failed to initialise - %s\n", gnutls_strerror(ret)));
448         params->tls_enabled = False;
449         talloc_free(tmp_ctx);
450         return params;
451 }
452
453
454 /*
455   setup for a new connection
456 */
457 struct socket_context *tls_init_server(struct tls_params *params, 
458                                        struct socket_context *socket,
459                                        struct fd_event *fde, 
460                                        const char *plain_chars)
461 {
462         struct tls_context *tls;
463         int ret;
464         struct socket_context *new_sock;
465         NTSTATUS nt_status;
466         
467         nt_status = socket_create_with_ops(socket, &tls_socket_ops, &new_sock, 
468                                            SOCKET_TYPE_STREAM, 
469                                            socket->flags | SOCKET_FLAG_ENCRYPT);
470         if (!NT_STATUS_IS_OK(nt_status)) {
471                 return NULL;
472         }
473
474         tls = talloc(new_sock, struct tls_context);
475         if (tls == NULL) {
476                 return NULL;
477         }
478
479         tls->socket          = socket;
480         tls->fde             = fde;
481         if (talloc_reference(tls, fde) == NULL) {
482                 talloc_free(new_sock);
483                 return NULL;
484         }
485         if (talloc_reference(tls, socket) == NULL) {
486                 talloc_free(new_sock);
487                 return NULL;
488         }
489
490         new_sock->private_data    = tls;
491
492         if (!params->tls_enabled) {
493                 talloc_free(new_sock);
494                 return NULL;
495         }
496
497         TLSCHECK(gnutls_init(&tls->session, GNUTLS_SERVER));
498
499         talloc_set_destructor(tls, tls_destructor);
500
501         TLSCHECK(gnutls_set_default_priority(tls->session));
502         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE, 
503                                         params->x509_cred));
504         gnutls_certificate_server_set_request(tls->session, GNUTLS_CERT_REQUEST);
505         gnutls_dh_set_prime_bits(tls->session, DH_BITS);
506         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
507         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
508         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
509         gnutls_transport_set_lowat(tls->session, 0);
510
511         tls->plain_chars = plain_chars;
512         if (plain_chars) {
513                 tls->tls_detect = True;
514         } else {
515                 tls->tls_detect = False;
516         }
517
518         tls->output_pending  = False;
519         tls->done_handshake  = False;
520         tls->have_first_byte = False;
521         tls->tls_enabled     = True;
522         tls->interrupted     = False;
523         
524         new_sock->state = SOCKET_STATE_SERVER_CONNECTED;
525
526         return new_sock;
527
528 failed:
529         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
530         talloc_free(new_sock);
531         return NULL;
532 }
533
534
535 /*
536   setup for a new client connection
537 */
538 struct socket_context *tls_init_client(struct socket_context *socket,
539                                        struct fd_event *fde)
540 {
541         struct tls_context *tls;
542         int ret = 0;
543         const int cert_type_priority[] = { GNUTLS_CRT_X509, GNUTLS_CRT_OPENPGP, 0 };
544         char *cafile;
545         struct socket_context *new_sock;
546         NTSTATUS nt_status;
547         
548         nt_status = socket_create_with_ops(socket, &tls_socket_ops, &new_sock, 
549                                            SOCKET_TYPE_STREAM, 
550                                            socket->flags | SOCKET_FLAG_ENCRYPT);
551         if (!NT_STATUS_IS_OK(nt_status)) {
552                 return NULL;
553         }
554
555         tls = talloc(new_sock, struct tls_context);
556         if (tls == NULL) return NULL;
557
558         tls->socket          = socket;
559         tls->fde             = fde;
560         if (talloc_reference(tls, fde) == NULL) {
561                 return NULL;
562         }
563         if (talloc_reference(tls, socket) == NULL) {
564                 return NULL;
565         }
566         new_sock->private_data    = tls;
567
568         cafile = private_path(tls, global_loadparm, lp_tls_cafile(global_loadparm));
569         if (!cafile || !*cafile) {
570                 goto failed;
571         }
572
573         gnutls_global_init();
574
575         gnutls_certificate_allocate_credentials(&tls->xcred);
576         gnutls_certificate_set_x509_trust_file(tls->xcred, cafile, GNUTLS_X509_FMT_PEM);
577         talloc_free(cafile);
578         TLSCHECK(gnutls_init(&tls->session, GNUTLS_CLIENT));
579         TLSCHECK(gnutls_set_default_priority(tls->session));
580         gnutls_certificate_type_set_priority(tls->session, cert_type_priority);
581         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE, tls->xcred));
582
583         talloc_set_destructor(tls, tls_destructor);
584
585         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
586         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
587         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
588         gnutls_transport_set_lowat(tls->session, 0);
589         tls->tls_detect = False;
590
591         tls->output_pending  = False;
592         tls->done_handshake  = False;
593         tls->have_first_byte = False;
594         tls->tls_enabled     = True;
595         tls->interrupted     = False;
596         
597         new_sock->state = SOCKET_STATE_CLIENT_CONNECTED;
598
599         return new_sock;
600
601 failed:
602         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
603         tls->tls_enabled = False;
604         return new_sock;
605 }
606
607 static NTSTATUS tls_socket_set_option(struct socket_context *sock, const char *option, const char *val)
608 {
609         set_socket_options(socket_get_fd(sock), option);
610         return NT_STATUS_OK;
611 }
612
613 static char *tls_socket_get_peer_name(struct socket_context *sock, TALLOC_CTX *mem_ctx)
614 {
615         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
616         return socket_get_peer_name(tls->socket, mem_ctx);
617 }
618
619 static struct socket_address *tls_socket_get_peer_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
620 {
621         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
622         return socket_get_peer_addr(tls->socket, mem_ctx);
623 }
624
625 static struct socket_address *tls_socket_get_my_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
626 {
627         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
628         return socket_get_my_addr(tls->socket, mem_ctx);
629 }
630
631 static int tls_socket_get_fd(struct socket_context *sock)
632 {
633         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
634         return socket_get_fd(tls->socket);
635 }
636
637 static const struct socket_ops tls_socket_ops = {
638         .name                   = "tls",
639         .fn_init                = tls_socket_init,
640         .fn_recv                = tls_socket_recv,
641         .fn_send                = tls_socket_send,
642         .fn_pending             = tls_socket_pending,
643
644         .fn_set_option          = tls_socket_set_option,
645
646         .fn_get_peer_name       = tls_socket_get_peer_name,
647         .fn_get_peer_addr       = tls_socket_get_peer_addr,
648         .fn_get_my_addr         = tls_socket_get_my_addr,
649         .fn_get_fd              = tls_socket_get_fd
650 };
651
652 BOOL tls_support(struct tls_params *params)
653 {
654         return params->tls_enabled;
655 }
656
657 #else
658
659 /* for systems without tls we just fail the operations, and the caller
660  * will retain the original socket */
661
662 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
663 {
664         return talloc_new(mem_ctx);
665 }
666
667 /*
668   setup for a new connection
669 */
670 struct socket_context *tls_init_server(struct tls_params *params, 
671                                     struct socket_context *socket,
672                                     struct fd_event *fde, 
673                                     const char *plain_chars)
674 {
675         return NULL;
676 }
677
678
679 /*
680   setup for a new client connection
681 */
682 struct socket_context *tls_init_client(struct socket_context *socket,
683                                        struct fd_event *fde)
684 {
685         return NULL;
686 }
687
688 BOOL tls_support(struct tls_params *params)
689 {
690         return False;
691 }
692
693 #endif
694