s4-auth: fixed infinite loop in krb5 auth
[kai/samba-autobuild/.git] / source4 / auth / kerberos / krb5_init_context.c
1 /*
2    Unix SMB/CIFS implementation.
3    Wrapper for krb5_init_context
4
5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
6    Copyright (C) Andrew Tridgell 2005
7    Copyright (C) Stefan Metzmacher 2004
8
9    This program is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 3 of the License, or
12    (at your option) any later version.
13
14    This program is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18
19    You should have received a copy of the GNU General Public License
20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
21 */
22
23 #include "includes.h"
24 #include "system/kerberos.h"
25 #include <tevent.h>
26 #include "auth/kerberos/kerberos.h"
27 #include "lib/socket/socket.h"
28 #include "lib/stream/packet.h"
29 #include "system/network.h"
30 #include "param/param.h"
31 #include "libcli/resolve/resolve.h"
32 #include "../lib/tsocket/tsocket.h"
33
34 /*
35   context structure for operations on cldap packets
36 */
37 struct smb_krb5_socket {
38         struct socket_context *sock;
39
40         /* the fd event */
41         struct tevent_fd *fde;
42
43         NTSTATUS status;
44         DATA_BLOB request, reply;
45
46         struct packet_context *packet;
47
48         size_t partial_read;
49
50         krb5_krbhst_info *hi;
51 };
52
53 static krb5_error_code smb_krb5_context_destroy(struct smb_krb5_context *ctx)
54 {
55         /* Otherwise krb5_free_context will try and close what we have already free()ed */
56         krb5_set_warn_dest(ctx->krb5_context, NULL);
57         krb5_closelog(ctx->krb5_context, ctx->logf);
58         krb5_free_context(ctx->krb5_context);
59         return 0;
60 }
61
62 /* We never close down the DEBUG system, and no need to unreference the use */
63 static void smb_krb5_debug_close(void *private_data) {
64         return;
65 }
66
67 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private_data)
68 {
69         DEBUG(3, ("Kerberos: %s\n", msg));
70 }
71
72 /*
73   handle recv events on a smb_krb5 socket
74 */
75 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
76 {
77         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
78         DATA_BLOB blob;
79         size_t nread, dsize;
80
81         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
82         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
83                 talloc_free(tmp_ctx);
84                 return;
85         }
86
87         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
88         if (blob.data == NULL && dsize != 0) {
89                 smb_krb5->status = NT_STATUS_NO_MEMORY;
90                 talloc_free(tmp_ctx);
91                 return;
92         }
93
94         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
95         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
96                 talloc_free(tmp_ctx);
97                 return;
98         }
99         blob.length = nread;
100
101         if (nread == 0) {
102                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
103                 talloc_free(tmp_ctx);
104                 return;
105         }
106
107         DEBUG(2,("Received smb_krb5 packet of length %d\n",
108                  (int)blob.length));
109
110         talloc_steal(smb_krb5, blob.data);
111         smb_krb5->reply = blob;
112         talloc_free(tmp_ctx);
113 }
114
115 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
116 {
117         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
118         talloc_steal(smb_krb5, data.data);
119         smb_krb5->reply = data;
120         smb_krb5->reply.length -= 4;
121         smb_krb5->reply.data += 4;
122         return NT_STATUS_OK;
123 }
124
125 /*
126   handle request timeouts
127 */
128 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
129                                   struct tevent_timer *te, struct timeval t,
130                                   void *private_data)
131 {
132         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
133         DEBUG(5,("Timed out smb_krb5 packet\n"));
134         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
135 }
136
137 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
138 {
139         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
140         smb_krb5->status = status;
141 }
142
143 /*
144   handle send events on a smb_krb5 socket
145 */
146 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
147 {
148         NTSTATUS status;
149
150         size_t len;
151
152         len = smb_krb5->request.length;
153         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
154
155         if (!NT_STATUS_IS_OK(status)) return;
156
157         TEVENT_FD_READABLE(smb_krb5->fde);
158
159         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
160         return;
161 }
162
163
164 /*
165   handle fd events on a smb_krb5_socket
166 */
167 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
168                                  uint16_t flags, void *private_data)
169 {
170         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
171         switch (smb_krb5->hi->proto) {
172         case KRB5_KRBHST_UDP:
173                 if (flags & TEVENT_FD_READ) {
174                         smb_krb5_socket_recv(smb_krb5);
175                         return;
176                 }
177                 if (flags & TEVENT_FD_WRITE) {
178                         smb_krb5_socket_send(smb_krb5);
179                         return;
180                 }
181                 /* not reached */
182                 return;
183         case KRB5_KRBHST_TCP:
184                 if (flags & TEVENT_FD_READ) {
185                         packet_recv(smb_krb5->packet);
186                         return;
187                 }
188                 if (flags & TEVENT_FD_WRITE) {
189                         packet_queue_run(smb_krb5->packet);
190                         return;
191                 }
192                 /* not reached */
193                 return;
194         case KRB5_KRBHST_HTTP:
195                 /* can't happen */
196                 break;
197         }
198 }
199
200
201 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
202                                             void *data,
203                                             krb5_krbhst_info *hi,
204                                             time_t timeout,
205                                             const krb5_data *send_buf,
206                                             krb5_data *recv_buf)
207 {
208         krb5_error_code ret;
209         NTSTATUS status;
210         const char *name;
211         struct addrinfo *ai, *a;
212         struct smb_krb5_socket *smb_krb5;
213
214         DATA_BLOB send_blob;
215
216         struct tevent_context *ev;
217         TALLOC_CTX *tmp_ctx = talloc_new(NULL);
218         if (!tmp_ctx) {
219                 return ENOMEM;
220         }
221
222         if (!data) {
223                 /* If no event context was available, then create one for this loop */
224                 ev = tevent_context_init(tmp_ctx);
225                 if (!ev) {
226                         talloc_free(tmp_ctx);
227                         return ENOMEM;
228                 }
229         } else {
230                 ev = talloc_get_type_abort(data, struct tevent_context);
231         }
232
233         send_blob = data_blob_const(send_buf->data, send_buf->length);
234
235         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
236         if (ret) {
237                 talloc_free(tmp_ctx);
238                 return ret;
239         }
240
241         for (a = ai; a; a = a->ai_next) {
242                 struct socket_address *remote_addr;
243                 smb_krb5 = talloc(tmp_ctx, struct smb_krb5_socket);
244                 if (!smb_krb5) {
245                         talloc_free(tmp_ctx);
246                         return ENOMEM;
247                 }
248                 smb_krb5->hi = hi;
249
250                 switch (a->ai_family) {
251                 case PF_INET:
252                         name = "ipv4";
253                         break;
254 #ifdef HAVE_IPV6
255                 case PF_INET6:
256                         name = "ipv6";
257                         break;
258 #endif
259                 default:
260                         talloc_free(tmp_ctx);
261                         return EINVAL;
262                 }
263
264                 status = NT_STATUS_INVALID_PARAMETER;
265                 switch (hi->proto) {
266                 case KRB5_KRBHST_UDP:
267                         status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
268                         break;
269                 case KRB5_KRBHST_TCP:
270                         status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
271                         break;
272                 case KRB5_KRBHST_HTTP:
273                         talloc_free(tmp_ctx);
274                         return EINVAL;
275                 }
276                 if (!NT_STATUS_IS_OK(status)) {
277                         talloc_free(smb_krb5);
278                         continue;
279                 }
280
281                 talloc_steal(smb_krb5, smb_krb5->sock);
282
283                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
284                 if (!remote_addr) {
285                         talloc_free(smb_krb5);
286                         continue;
287                 }
288
289                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
290                 if (!NT_STATUS_IS_OK(status)) {
291                         talloc_free(smb_krb5);
292                         continue;
293                 }
294
295                 /* Setup the FDE, start listening for read events
296                  * from the start (otherwise we may miss a socket
297                  * drop) and mark as AUTOCLOSE along with the fde */
298
299                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
300                 smb_krb5->fde = tevent_add_fd(ev, smb_krb5->sock,
301                                               socket_get_fd(smb_krb5->sock),
302                                               TEVENT_FD_READ,
303                                               smb_krb5_socket_handler, smb_krb5);
304                 /* its now the job of the event layer to close the socket */
305                 tevent_fd_set_close_fn(smb_krb5->fde, socket_tevent_fd_close_fn);
306                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
307
308                 tevent_add_timer(ev, smb_krb5,
309                                  timeval_current_ofs(timeout, 0),
310                                  smb_krb5_request_timeout, smb_krb5);
311
312                 smb_krb5->status = NT_STATUS_OK;
313                 smb_krb5->reply = data_blob(NULL, 0);
314
315                 switch (hi->proto) {
316                 case KRB5_KRBHST_UDP:
317                         TEVENT_FD_WRITEABLE(smb_krb5->fde);
318                         smb_krb5->request = send_blob;
319                         break;
320                 case KRB5_KRBHST_TCP:
321
322                         smb_krb5->packet = packet_init(smb_krb5);
323                         if (smb_krb5->packet == NULL) {
324                                 talloc_free(smb_krb5);
325                                 return ENOMEM;
326                         }
327                         packet_set_private(smb_krb5->packet, smb_krb5);
328                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
329                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
330                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
331                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
332                         packet_set_event_context(smb_krb5->packet, ev);
333                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
334
335                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
336                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
337                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
338                         packet_send(smb_krb5->packet, smb_krb5->request);
339                         break;
340                 case KRB5_KRBHST_HTTP:
341                         talloc_free(tmp_ctx);
342                         return EINVAL;
343                 }
344                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
345                         if (tevent_loop_once(ev) != 0) {
346                                 talloc_free(tmp_ctx);
347                                 return EINVAL;
348                         }
349
350                         /* After each and every event loop, reset the
351                          * send_to_kdc pointers to what they were when
352                          * we entered this loop.  That way, if a
353                          * nested event has invalidated them, we put
354                          * it back before we return to the heimdal
355                          * code */
356                         ret = krb5_set_send_to_kdc_func(context,
357                                                         smb_krb5_send_and_recv_func,
358                                                         data);
359                         if (ret != 0) {
360                                 talloc_free(tmp_ctx);
361                                 return ret;
362                         }
363                 }
364                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
365                         talloc_free(smb_krb5);
366                         continue;
367                 }
368
369                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
370                         struct tsocket_address *addr = socket_address_to_tsocket_address(smb_krb5, remote_addr);
371                         const char *addr_string = NULL;
372                         if (addr) {
373                                 addr_string = tsocket_address_inet_addr_string(addr, smb_krb5);
374                         } else {
375                                 addr_string = NULL;
376                         }
377                         DEBUG(2,("Error reading smb_krb5 reply packet: %s from %s\n", nt_errstr(smb_krb5->status),
378                                  addr_string));
379                         talloc_free(smb_krb5);
380                         continue;
381                 }
382
383                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
384                 if (ret) {
385                         talloc_free(tmp_ctx);
386                         return ret;
387                 }
388                 talloc_free(smb_krb5);
389
390                 break;
391         }
392         talloc_free(tmp_ctx);
393         if (a) {
394                 return 0;
395         }
396         return KRB5_KDC_UNREACH;
397 }
398
399 krb5_error_code
400 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
401                             struct loadparm_context *lp_ctx,
402                             krb5_context *_krb5_context)
403 {
404         krb5_error_code ret;
405         char **config_files;
406         const char *config_file, *realm;
407         krb5_context krb5_ctx;
408
409         initialize_krb5_error_table();
410
411         ret = krb5_init_context(&krb5_ctx);
412         if (ret) {
413                 DEBUG(1,("krb5_init_context failed (%s)\n",
414                          error_message(ret)));
415                 return ret;
416         }
417
418         config_file = config_path(tmp_ctx, lp_ctx, "krb5.conf");
419         if (!config_file) {
420                 krb5_free_context(krb5_ctx);
421                 return ENOMEM;
422         }
423
424         /* Use our local krb5.conf file by default */
425         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
426         if (ret) {
427                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
428                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
429                 krb5_free_context(krb5_ctx);
430                 return ret;
431         }
432
433         ret = krb5_set_config_files(krb5_ctx, config_files);
434         krb5_free_config_files(config_files);
435         if (ret) {
436                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
437                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
438                 krb5_free_context(krb5_ctx);
439                 return ret;
440         }
441
442         realm = lpcfg_realm(lp_ctx);
443         if (realm != NULL) {
444                 ret = krb5_set_default_realm(krb5_ctx, realm);
445                 if (ret) {
446                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
447                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
448                         krb5_free_context(krb5_ctx);
449                         return ret;
450                 }
451         }
452
453         *_krb5_context = krb5_ctx;
454         return 0;
455 }
456
457 krb5_error_code smb_krb5_init_context(void *parent_ctx,
458                                       struct tevent_context *ev,
459                                       struct loadparm_context *lp_ctx,
460                                       struct smb_krb5_context **smb_krb5_context)
461 {
462         krb5_error_code ret;
463         TALLOC_CTX *tmp_ctx;
464
465         initialize_krb5_error_table();
466
467         tmp_ctx = talloc_new(parent_ctx);
468         *smb_krb5_context = talloc_zero(tmp_ctx, struct smb_krb5_context);
469
470         if (!*smb_krb5_context || !tmp_ctx) {
471                 talloc_free(tmp_ctx);
472                 return ENOMEM;
473         }
474
475         ret = smb_krb5_init_context_basic(tmp_ctx, lp_ctx,
476                                           &(*smb_krb5_context)->krb5_context);
477         if (ret) {
478                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
479                          error_message(ret)));
480                 talloc_free(tmp_ctx);
481                 return ret;
482         }
483
484         /* TODO: Should we have a different name here? */
485         ret = krb5_initlog((*smb_krb5_context)->krb5_context, "Samba", &(*smb_krb5_context)->logf);
486
487         if (ret) {
488                 DEBUG(1,("krb5_initlog failed (%s)\n",
489                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
490                 krb5_free_context((*smb_krb5_context)->krb5_context);
491                 talloc_free(tmp_ctx);
492                 return ret;
493         }
494
495         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
496
497         ret = krb5_addlog_func((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf, 0 /* min */, -1 /* max */,
498                                smb_krb5_debug_wrapper, smb_krb5_debug_close, NULL);
499         if (ret) {
500                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
501                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
502                 talloc_free(tmp_ctx);
503                 return ret;
504         }
505         krb5_set_warn_dest((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf);
506
507         /* Set use of our socket lib */
508         if (ev) {
509                 struct tevent_context *previous_ev;
510                 ret = smb_krb5_context_set_event_ctx(*smb_krb5_context,
511                                                      ev, &previous_ev);
512                 if (ret) {
513                         talloc_free(tmp_ctx);
514                         return ret;
515                 }
516         }
517
518         talloc_steal(parent_ctx, *smb_krb5_context);
519         talloc_free(tmp_ctx);
520
521         /* Set options in kerberos */
522
523         krb5_set_dns_canonicalize_hostname((*smb_krb5_context)->krb5_context,
524                                            lpcfg_parm_bool(lp_ctx, NULL, "krb5", "set_dns_canonicalize", false));
525
526         return 0;
527 }
528
529 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
530                                                struct tevent_context *ev,
531                                                struct tevent_context **previous_ev)
532 {
533         int ret;
534         if (!ev) {
535                 return EINVAL;
536         }
537
538         *previous_ev = smb_krb5_context->current_ev;
539
540         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
541         if (!smb_krb5_context->current_ev) {
542                 return ENOMEM;
543         }
544
545         /* Set use of our socket lib */
546         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
547                                         smb_krb5_send_and_recv_func,
548                                         ev);
549         if (ret) {
550                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
551                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
552                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
553                 talloc_free(tmp_ctx);
554                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
555                 smb_krb5_context->current_ev = NULL;
556                 return ret;
557         }
558         return 0;
559 }
560
561 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
562                                                   struct tevent_context *previous_ev,
563                                                   struct tevent_context *ev)
564 {
565         int ret;
566         talloc_unlink(smb_krb5_context, ev);
567         /* If there was a mismatch with things happening on a stack, then don't wipe things */
568         smb_krb5_context->current_ev = previous_ev;
569         /* Set use of our socket lib */
570         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
571                                         smb_krb5_send_and_recv_func,
572                                         previous_ev);
573         if (ret) {
574                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
575                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
576                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
577                 talloc_free(tmp_ctx);
578                 return ret;
579         }
580         return 0;
581 }