source: trunk/server/source4/auth/kerberos/kerberos_util.c

Last change on this file was 745, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated trunk to 3.6.0
File size: 29.6 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 Kerberos utility functions for GENSEC
5
6 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
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 "auth/kerberos/kerberos.h"
26#include "auth/credentials/credentials.h"
27#include "auth/credentials/credentials_proto.h"
28#include "auth/credentials/credentials_krb5.h"
29#include "auth/kerberos/kerberos_credentials.h"
30#include "auth/kerberos/kerberos_util.h"
31#include <ldb.h>
32#include "param/secrets.h"
33
34struct principal_container {
35 struct smb_krb5_context *smb_krb5_context;
36 krb5_principal principal;
37 const char *string_form; /* Optional */
38};
39
40static krb5_error_code free_principal(struct principal_container *pc)
41{
42 /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
43 krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
44
45 return 0;
46}
47
48
49static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
50 const char *princ_string,
51 struct smb_krb5_context *smb_krb5_context,
52 krb5_principal *princ,
53 const char **error_string)
54{
55 int ret;
56 struct principal_container *mem_ctx;
57 if (princ_string == NULL) {
58 *princ = NULL;
59 return 0;
60 }
61
62 ret = krb5_parse_name(smb_krb5_context->krb5_context,
63 princ_string, princ);
64
65 if (ret) {
66 (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
67 return ret;
68 }
69
70 mem_ctx = talloc(parent_ctx, struct principal_container);
71 if (!mem_ctx) {
72 (*error_string) = error_message(ENOMEM);
73 return ENOMEM;
74 }
75
76 /* This song-and-dance effectivly puts the principal
77 * into talloc, so we can't loose it. */
78 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
79 mem_ctx->principal = *princ;
80 talloc_set_destructor(mem_ctx, free_principal);
81 return 0;
82}
83
84static krb5_error_code principals_from_msg(TALLOC_CTX *parent_ctx,
85 struct ldb_message *msg,
86 struct smb_krb5_context *smb_krb5_context,
87 struct principal_container ***principals_out,
88 const char **error_string)
89{
90 unsigned int i;
91 krb5_error_code ret;
92 char *upper_realm;
93 const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
94 const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL);
95 struct ldb_message_element *spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
96 TALLOC_CTX *tmp_ctx;
97 struct principal_container **principals;
98 tmp_ctx = talloc_new(parent_ctx);
99 if (!tmp_ctx) {
100 *error_string = "Cannot allocate tmp_ctx";
101 return ENOMEM;
102 }
103
104 if (!realm) {
105 *error_string = "Cannot have a kerberos secret in secrets.ldb without a realm";
106 return EINVAL;
107 }
108
109 upper_realm = strupper_talloc(tmp_ctx, realm);
110 if (!upper_realm) {
111 talloc_free(tmp_ctx);
112 *error_string = "Cannot allocate full upper case realm";
113 return ENOMEM;
114 }
115
116 principals = talloc_array(tmp_ctx, struct principal_container *, spn_el ? (spn_el->num_values + 2) : 2);
117
118 spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
119 for (i=0; spn_el && i < spn_el->num_values; i++) {
120 principals[i] = talloc(principals, struct principal_container);
121 if (!principals[i]) {
122 talloc_free(tmp_ctx);
123 *error_string = "Cannot allocate mem_ctx";
124 return ENOMEM;
125 }
126
127 principals[i]->smb_krb5_context = talloc_reference(principals[i], smb_krb5_context);
128 principals[i]->string_form = talloc_asprintf(principals[i], "%*.*s@%s",
129 (int)spn_el->values[i].length,
130 (int)spn_el->values[i].length,
131 (const char *)spn_el->values[i].data, upper_realm);
132 if (!principals[i]->string_form) {
133 talloc_free(tmp_ctx);
134 *error_string = "Cannot allocate full samAccountName";
135 return ENOMEM;
136 }
137
138 ret = krb5_parse_name(smb_krb5_context->krb5_context,
139 principals[i]->string_form, &principals[i]->principal);
140
141 if (ret) {
142 talloc_free(tmp_ctx);
143 (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
144 return ret;
145 }
146
147 /* This song-and-dance effectivly puts the principal
148 * into talloc, so we can't loose it. */
149 talloc_set_destructor(principals[i], free_principal);
150 }
151
152 if (samAccountName) {
153 principals[i] = talloc(principals, struct principal_container);
154 if (!principals[i]) {
155 talloc_free(tmp_ctx);
156 *error_string = "Cannot allocate mem_ctx";
157 return ENOMEM;
158 }
159
160 principals[i]->smb_krb5_context = talloc_reference(principals[i], smb_krb5_context);
161 principals[i]->string_form = talloc_asprintf(parent_ctx, "%s@%s", samAccountName, upper_realm);
162 if (!principals[i]->string_form) {
163 talloc_free(tmp_ctx);
164 *error_string = "Cannot allocate full samAccountName";
165 return ENOMEM;
166 }
167
168 ret = krb5_make_principal(smb_krb5_context->krb5_context, &principals[i]->principal, upper_realm, samAccountName,
169 NULL);
170 if (ret) {
171 talloc_free(tmp_ctx);
172 (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
173 return ret;
174 }
175
176 /* This song-and-dance effectivly puts the principal
177 * into talloc, so we can't loose it. */
178 talloc_set_destructor(principals[i], free_principal);
179 i++;
180 }
181
182 principals[i] = NULL;
183 *principals_out = talloc_steal(parent_ctx, principals);
184
185 talloc_free(tmp_ctx);
186 return ret;
187}
188
189static krb5_error_code salt_principal_from_msg(TALLOC_CTX *parent_ctx,
190 struct ldb_message *msg,
191 struct smb_krb5_context *smb_krb5_context,
192 krb5_principal *salt_princ,
193 const char **error_string)
194{
195 const char *salt_principal = ldb_msg_find_attr_as_string(msg, "saltPrincipal", NULL);
196 const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL);
197 const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
198 if (salt_principal) {
199 return parse_principal(parent_ctx, salt_principal, smb_krb5_context, salt_princ, error_string);
200 } else if (samAccountName) {
201 krb5_error_code ret;
202 char *machine_username;
203 char *salt_body;
204 char *lower_realm;
205 char *upper_realm;
206
207 TALLOC_CTX *tmp_ctx;
208 struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
209 if (!mem_ctx) {
210 *error_string = "Cannot allocate mem_ctx";
211 return ENOMEM;
212 }
213
214 tmp_ctx = talloc_new(mem_ctx);
215 if (!tmp_ctx) {
216 talloc_free(mem_ctx);
217 *error_string = "Cannot allocate tmp_ctx";
218 return ENOMEM;
219 }
220
221 if (!realm) {
222 *error_string = "Cannot have a kerberos secret in secrets.ldb without a realm";
223 return EINVAL;
224 }
225
226 machine_username = talloc_strdup(tmp_ctx, samAccountName);
227 if (!machine_username) {
228 talloc_free(mem_ctx);
229 *error_string = "Cannot duplicate samAccountName";
230 return ENOMEM;
231 }
232
233 if (machine_username[strlen(machine_username)-1] == '$') {
234 machine_username[strlen(machine_username)-1] = '\0';
235 }
236
237 lower_realm = strlower_talloc(tmp_ctx, realm);
238 if (!lower_realm) {
239 talloc_free(mem_ctx);
240 *error_string = "Cannot allocate to lower case realm";
241 return ENOMEM;
242 }
243
244 upper_realm = strupper_talloc(tmp_ctx, realm);
245 if (!upper_realm) {
246 talloc_free(mem_ctx);
247 *error_string = "Cannot allocate to upper case realm";
248 return ENOMEM;
249 }
250
251 salt_body = talloc_asprintf(tmp_ctx, "%s.%s", machine_username,
252 lower_realm);
253 talloc_free(lower_realm);
254 talloc_free(machine_username);
255 if (!salt_body) {
256 talloc_free(mem_ctx);
257 *error_string = "Cannot form salt principal body";
258 return ENOMEM;
259 }
260
261 ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
262 upper_realm,
263 "host", salt_body, NULL);
264 if (ret == 0) {
265 /* This song-and-dance effectivly puts the principal
266 * into talloc, so we can't loose it. */
267 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
268 mem_ctx->principal = *salt_princ;
269 talloc_set_destructor(mem_ctx, free_principal);
270 } else {
271 (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
272 }
273 talloc_free(tmp_ctx);
274 return ret;
275 } else {
276 (*error_string) = "Cannot determine salt principal, no saltPrincipal or samAccountName specified";
277 return EINVAL;
278 }
279}
280
281/* Obtain the principal set on this context. Requires a
282 * smb_krb5_context because we are doing krb5 principal parsing with
283 * the library routines. The returned princ is placed in the talloc
284 * system by means of a destructor (do *not* free). */
285
286krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
287 struct cli_credentials *credentials,
288 struct smb_krb5_context *smb_krb5_context,
289 krb5_principal *princ,
290 enum credentials_obtained *obtained,
291 const char **error_string)
292{
293 krb5_error_code ret;
294 const char *princ_string;
295 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
296 if (!mem_ctx) {
297 (*error_string) = error_message(ENOMEM);
298 return ENOMEM;
299 }
300 princ_string = cli_credentials_get_principal_and_obtained(credentials, mem_ctx, obtained);
301 if (!princ_string) {
302 (*error_string) = error_message(ENOMEM);
303 return ENOMEM;
304 }
305
306 ret = parse_principal(parent_ctx, princ_string,
307 smb_krb5_context, princ, error_string);
308 talloc_free(mem_ctx);
309 return ret;
310}
311
312/* Obtain the principal set on this context. Requires a
313 * smb_krb5_context because we are doing krb5 principal parsing with
314 * the library routines. The returned princ is placed in the talloc
315 * system by means of a destructor (do *not* free). */
316
317 krb5_error_code impersonate_principal_from_credentials(TALLOC_CTX *parent_ctx,
318 struct cli_credentials *credentials,
319 struct smb_krb5_context *smb_krb5_context,
320 krb5_principal *princ,
321 const char **error_string)
322{
323 return parse_principal(parent_ctx, cli_credentials_get_impersonate_principal(credentials),
324 smb_krb5_context, princ, error_string);
325}
326
327/**
328 * Return a freshly allocated ccache (destroyed by destructor on child
329 * of parent_ctx), for a given set of client credentials
330 */
331
332 krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
333 struct cli_credentials *credentials,
334 struct smb_krb5_context *smb_krb5_context,
335 struct tevent_context *event_ctx,
336 krb5_ccache ccache,
337 enum credentials_obtained *obtained,
338 const char **error_string)
339{
340 krb5_error_code ret;
341 const char *password, *target_service;
342 time_t kdc_time = 0;
343 krb5_principal princ;
344 krb5_principal impersonate_principal;
345 int tries;
346 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
347 krb5_get_init_creds_opt *krb_options;
348
349 if (!mem_ctx) {
350 (*error_string) = strerror(ENOMEM);
351 return ENOMEM;
352 }
353
354 ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
355 if (ret) {
356 talloc_free(mem_ctx);
357 return ret;
358 }
359
360 ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
361 if (ret) {
362 talloc_free(mem_ctx);
363 return ret;
364 }
365
366 target_service = cli_credentials_get_target_service(credentials);
367
368 password = cli_credentials_get_password(credentials);
369
370 /* setup the krb5 options we want */
371 if ((ret = krb5_get_init_creds_opt_alloc(smb_krb5_context->krb5_context, &krb_options))) {
372 (*error_string) = talloc_asprintf(credentials, "krb5_get_init_creds_opt_alloc failed (%s)\n",
373 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
374 ret, mem_ctx));
375 talloc_free(mem_ctx);
376 return ret;
377 }
378
379 /* get the defaults */
380 krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
381
382 /* set if we want a forwardable ticket */
383 switch (cli_credentials_get_krb_forwardable(credentials)) {
384 case CRED_AUTO_KRB_FORWARDABLE:
385 break;
386 case CRED_NO_KRB_FORWARDABLE:
387 krb5_get_init_creds_opt_set_forwardable(krb_options, FALSE);
388 break;
389 case CRED_FORCE_KRB_FORWARDABLE:
390 krb5_get_init_creds_opt_set_forwardable(krb_options, TRUE);
391 break;
392 }
393
394 tries = 2;
395 while (tries--) {
396 struct tevent_context *previous_ev;
397 /* Do this every time, in case we have weird recursive issues here */
398 ret = smb_krb5_context_set_event_ctx(smb_krb5_context, event_ctx, &previous_ev);
399 if (ret) {
400 talloc_free(mem_ctx);
401 return ret;
402 }
403 if (password) {
404 ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
405 princ, password,
406 impersonate_principal, target_service,
407 krb_options,
408 NULL, &kdc_time);
409 } else if (impersonate_principal) {
410 talloc_free(mem_ctx);
411 (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock. A password must be specified in the credentials";
412 return EINVAL;
413 } else {
414 /* No password available, try to use a keyblock instead */
415
416 krb5_keyblock keyblock;
417 const struct samr_Password *mach_pwd;
418 mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
419 if (!mach_pwd) {
420 talloc_free(mem_ctx);
421 (*error_string) = "kinit_to_ccache: No password available for kinit\n";
422 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
423 smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
424 return EINVAL;
425 }
426 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
427 ENCTYPE_ARCFOUR_HMAC,
428 mach_pwd->hash, sizeof(mach_pwd->hash),
429 &keyblock);
430
431 if (ret == 0) {
432 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
433 princ, &keyblock,
434 target_service, krb_options,
435 NULL, &kdc_time);
436 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
437 }
438 }
439
440 smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
441
442 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
443 /* Perhaps we have been given an invalid skew, so try again without it */
444 time_t t = time(NULL);
445 krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
446 } else {
447 /* not a skew problem */
448 break;
449 }
450 }
451
452 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
453
454 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
455 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
456 cli_credentials_get_principal(credentials, mem_ctx),
457 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
458 ret, mem_ctx));
459 talloc_free(mem_ctx);
460 return ret;
461 }
462
463 /* cope with ticket being in the future due to clock skew */
464 if ((unsigned)kdc_time > time(NULL)) {
465 time_t t = time(NULL);
466 int time_offset =(unsigned)kdc_time-t;
467 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
468 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
469 }
470
471 if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
472 ret = kinit_to_ccache(parent_ctx,
473 credentials,
474 smb_krb5_context,
475 event_ctx,
476 ccache, obtained,
477 error_string);
478 }
479
480 if (ret) {
481 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
482 cli_credentials_get_principal(credentials, mem_ctx),
483 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
484 ret, mem_ctx));
485 talloc_free(mem_ctx);
486 return ret;
487 }
488 talloc_free(mem_ctx);
489 return 0;
490}
491
492static krb5_error_code free_keytab(struct keytab_container *ktc)
493{
494 return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
495}
496
497krb5_error_code smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
498 struct smb_krb5_context *smb_krb5_context,
499 const char *keytab_name, struct keytab_container **ktc)
500{
501 krb5_keytab keytab;
502 krb5_error_code ret;
503 ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
504 if (ret) {
505 DEBUG(1,("failed to open krb5 keytab: %s\n",
506 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
507 ret, mem_ctx)));
508 return ret;
509 }
510
511 *ktc = talloc(mem_ctx, struct keytab_container);
512 if (!*ktc) {
513 return ENOMEM;
514 }
515
516 (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
517 (*ktc)->keytab = keytab;
518 talloc_set_destructor(*ktc, free_keytab);
519
520 return 0;
521}
522
523static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
524 struct principal_container **principals,
525 krb5_principal salt_princ,
526 int kvno,
527 const char *password_s,
528 struct smb_krb5_context *smb_krb5_context,
529 krb5_enctype *enctypes,
530 krb5_keytab keytab,
531 const char **error_string)
532{
533 unsigned int i, p;
534 krb5_error_code ret;
535 krb5_data password;
536
537 password.data = discard_const_p(char *, password_s);
538 password.length = strlen(password_s);
539
540 for (i=0; enctypes[i]; i++) {
541 krb5_keytab_entry entry;
542
543 ZERO_STRUCT(entry);
544
545 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
546 salt_princ, &password, &entry.keyblock, enctypes[i]);
547 if (ret != 0) {
548 return ret;
549 }
550
551 entry.vno = kvno;
552
553 for (p=0; principals[p]; p++) {
554 entry.principal = principals[p]->principal;
555 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
556 if (ret != 0) {
557 char *k5_error_string = smb_get_krb5_error_message(smb_krb5_context->krb5_context,
558 ret, NULL);
559 *error_string = talloc_asprintf(parent_ctx, "Failed to add enctype %d entry for %s(kvno %d) to keytab: %s\n",
560 (int)enctypes[i],
561 principals[p]->string_form,
562 kvno,
563 k5_error_string);
564 talloc_free(k5_error_string);
565 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
566 return ret;
567 }
568
569 DEBUG(5, ("Added %s(kvno %d) to keytab (enctype %d)\n",
570 principals[p]->string_form, kvno,
571 (int)enctypes[i]));
572 }
573 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
574 }
575 return 0;
576}
577
578static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
579 struct ldb_message *msg,
580 struct principal_container **principals,
581 struct smb_krb5_context *smb_krb5_context,
582 krb5_keytab keytab,
583 bool add_old,
584 const char **error_string)
585{
586 krb5_error_code ret;
587 const char *password_s;
588 const char *old_secret;
589 int kvno;
590 uint32_t enctype_bitmap;
591 krb5_principal salt_princ;
592 krb5_enctype *enctypes;
593 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
594 if (!mem_ctx) {
595 *error_string = "unable to allocate tmp_ctx for create_keytab";
596 return ENOMEM;
597 }
598
599 /* The salt used to generate these entries may be different however, fetch that */
600 ret = salt_principal_from_msg(mem_ctx, msg,
601 smb_krb5_context,
602 &salt_princ, error_string);
603 if (ret) {
604 talloc_free(mem_ctx);
605 return ret;
606 }
607
608 kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
609
610 /* Finally, do the dance to get the password to put in the entry */
611 password_s = ldb_msg_find_attr_as_string(msg, "secret", NULL);
612
613 if (!password_s) {
614 /* There is no password here, so nothing to do */
615 talloc_free(mem_ctx);
616 return 0;
617 }
618
619 if (add_old && kvno != 0) {
620 old_secret = ldb_msg_find_attr_as_string(msg, "priorSecret", NULL);
621 } else {
622 old_secret = NULL;
623 }
624
625 enctype_bitmap = (uint32_t)ldb_msg_find_attr_as_int(msg, "msDS-SupportedEncryptionTypes", ENC_ALL_TYPES);
626
627 ret = kerberos_enctype_bitmap_to_enctypes(mem_ctx, enctype_bitmap, &enctypes);
628 if (ret) {
629 *error_string = talloc_asprintf(parent_ctx, "create_keytab: generating list of encryption types failed (%s)\n",
630 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
631 ret, mem_ctx));
632 talloc_free(mem_ctx);
633 return ret;
634 }
635
636 ret = keytab_add_keys(mem_ctx, principals,
637 salt_princ,
638 kvno, password_s, smb_krb5_context,
639 enctypes, keytab, error_string);
640 if (ret) {
641 talloc_free(mem_ctx);
642 return ret;
643 }
644
645 if (old_secret) {
646 ret = keytab_add_keys(mem_ctx, principals,
647 salt_princ,
648 kvno - 1, old_secret, smb_krb5_context,
649 enctypes, keytab, error_string);
650 if (ret) {
651 talloc_free(mem_ctx);
652 return ret;
653 }
654 }
655
656 talloc_free(mem_ctx);
657 return ret;
658}
659
660/*
661 * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
662 *
663 * These entries are now stale, we only keep the current, and previous entries around.
664 *
665 * Inspired by the code in Samba3 for 'use kerberos keytab'.
666 *
667 */
668
669static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
670 struct ldb_message *msg,
671 struct principal_container **principals,
672 bool delete_all_kvno,
673 struct smb_krb5_context *smb_krb5_context,
674 krb5_keytab keytab, bool *found_previous,
675 const char **error_string)
676{
677 krb5_error_code ret, ret2;
678 krb5_kt_cursor cursor;
679 int kvno;
680 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
681
682 if (!mem_ctx) {
683 return ENOMEM;
684 }
685
686 *found_previous = false;
687
688 kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
689
690 /* for each entry in the keytab */
691 ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
692 switch (ret) {
693 case 0:
694 break;
695 case HEIM_ERR_OPNOTSUPP:
696 case ENOENT:
697 case KRB5_KT_END:
698 /* no point enumerating if there isn't anything here */
699 talloc_free(mem_ctx);
700 return 0;
701 default:
702 *error_string = talloc_asprintf(parent_ctx, "failed to open keytab for read of old entries: %s\n",
703 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
704 ret, mem_ctx));
705 talloc_free(mem_ctx);
706 return ret;
707 }
708
709 while (!ret) {
710 unsigned int i;
711 bool matched = false;
712 krb5_keytab_entry entry;
713 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
714 if (ret) {
715 break;
716 }
717 for (i = 0; principals[i]; i++) {
718 /* if it matches our principal */
719 if (krb5_kt_compare(smb_krb5_context->krb5_context, &entry, principals[i]->principal, 0, 0)) {
720 matched = true;
721 break;
722 }
723 }
724
725 if (!matched) {
726 /* Free the entry, it wasn't the one we were looking for anyway */
727 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
728 continue;
729 }
730
731 /* delete it, if it is not kvno -1 */
732 if (entry.vno != (kvno - 1 )) {
733 /* Release the enumeration. We are going to
734 * have to start this from the top again,
735 * because deletes during enumeration may not
736 * always be consistant.
737 *
738 * Also, the enumeration locks a FILE: keytab
739 */
740
741 krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
742
743 ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
744 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
745
746 /* Deleted: Restart from the top */
747 ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
748 if (ret2) {
749 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
750 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
751 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
752 ret, mem_ctx)));
753
754 talloc_free(mem_ctx);
755 return ret2;
756 }
757
758 if (ret) {
759 break;
760 }
761
762 } else {
763 *found_previous = true;
764 }
765
766 /* Free the entry, we don't need it any more */
767 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
768
769
770 }
771 krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
772
773 switch (ret) {
774 case 0:
775 break;
776 case ENOENT:
777 case KRB5_KT_END:
778 ret = 0;
779 break;
780 default:
781 *error_string = talloc_asprintf(parent_ctx, "failed in deleting old entries for principal: %s\n",
782 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
783 ret, mem_ctx));
784 }
785 talloc_free(mem_ctx);
786 return ret;
787}
788
789krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
790 struct smb_krb5_context *smb_krb5_context,
791 struct ldb_context *ldb,
792 struct ldb_message *msg,
793 bool delete_all_kvno,
794 const char **error_string)
795{
796 krb5_error_code ret;
797 bool found_previous;
798 TALLOC_CTX *mem_ctx = talloc_new(NULL);
799 struct keytab_container *keytab_container;
800 struct principal_container **principals;
801 const char *keytab_name;
802
803 if (!mem_ctx) {
804 return ENOMEM;
805 }
806
807 keytab_name = keytab_name_from_msg(mem_ctx, ldb, msg);
808 if (!keytab_name) {
809 return ENOENT;
810 }
811
812 ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, &keytab_container);
813
814 if (ret != 0) {
815 talloc_free(mem_ctx);
816 return ret;
817 }
818
819 DEBUG(5, ("Opened keytab %s\n", keytab_name));
820
821 /* Get the principal we will store the new keytab entries under */
822 ret = principals_from_msg(mem_ctx, msg, smb_krb5_context, &principals, error_string);
823
824 if (ret != 0) {
825 *error_string = talloc_asprintf(parent_ctx, "Failed to load principals from ldb message: %s\n", *error_string);
826 talloc_free(mem_ctx);
827 return ret;
828 }
829
830 ret = remove_old_entries(mem_ctx, msg, principals, delete_all_kvno,
831 smb_krb5_context, keytab_container->keytab, &found_previous, error_string);
832 if (ret != 0) {
833 *error_string = talloc_asprintf(parent_ctx, "Failed to remove old principals from keytab: %s\n", *error_string);
834 talloc_free(mem_ctx);
835 return ret;
836 }
837
838 if (!delete_all_kvno) {
839 /* Create a new keytab. If during the cleanout we found
840 * entires for kvno -1, then don't try and duplicate them.
841 * Otherwise, add kvno, and kvno -1 */
842
843 ret = create_keytab(mem_ctx, msg, principals,
844 smb_krb5_context,
845 keytab_container->keytab,
846 found_previous ? false : true, error_string);
847 }
848 talloc_free(mem_ctx);
849 return ret;
850}
851
852krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
853 struct cli_credentials *machine_account,
854 struct smb_krb5_context *smb_krb5_context,
855 struct keytab_container **keytab_container)
856{
857 krb5_error_code ret;
858 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
859 const char *rand_string;
860 const char *keytab_name;
861 struct ldb_message *msg;
862 const char *error_string;
863 if (!mem_ctx) {
864 return ENOMEM;
865 }
866
867 *keytab_container = talloc(mem_ctx, struct keytab_container);
868
869 rand_string = generate_random_str(mem_ctx, 16);
870 if (!rand_string) {
871 talloc_free(mem_ctx);
872 return ENOMEM;
873 }
874
875 keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
876 rand_string);
877 if (!keytab_name) {
878 talloc_free(mem_ctx);
879 return ENOMEM;
880 }
881
882 ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
883 if (ret) {
884 return ret;
885 }
886
887 msg = ldb_msg_new(mem_ctx);
888 if (!msg) {
889 talloc_free(mem_ctx);
890 return ENOMEM;
891 }
892 ldb_msg_add_string(msg, "krb5Keytab", keytab_name);
893 ldb_msg_add_string(msg, "secret", cli_credentials_get_password(machine_account));
894 ldb_msg_add_string(msg, "samAccountName", cli_credentials_get_username(machine_account));
895 ldb_msg_add_string(msg, "realm", cli_credentials_get_realm(machine_account));
896 ldb_msg_add_fmt(msg, "msDS-KeyVersionNumber", "%d", (int)cli_credentials_get_kvno(machine_account));
897
898 ret = smb_krb5_update_keytab(mem_ctx, smb_krb5_context, NULL, msg, false, &error_string);
899 if (ret == 0) {
900 talloc_steal(parent_ctx, *keytab_container);
901 } else {
902 DEBUG(0, ("Failed to create in-memory keytab: %s\n", error_string));
903 *keytab_container = NULL;
904 }
905 talloc_free(mem_ctx);
906 return ret;
907}
908/* Translate between the IETF encryption type values and the Microsoft msDS-SupportedEncryptionTypes values */
909uint32_t kerberos_enctype_to_bitmap(krb5_enctype enc_type_enum)
910{
911 switch (enc_type_enum) {
912 case ENCTYPE_DES_CBC_CRC:
913 return ENC_CRC32;
914 case ENCTYPE_DES_CBC_MD5:
915 return ENC_RSA_MD5;
916 case ENCTYPE_ARCFOUR_HMAC_MD5:
917 return ENC_RC4_HMAC_MD5;
918 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
919 return ENC_HMAC_SHA1_96_AES128;
920 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
921 return ENC_HMAC_SHA1_96_AES256;
922 default:
923 return 0;
924 }
925}
926
927/* Translate between the Microsoft msDS-SupportedEncryptionTypes values and the IETF encryption type values */
928krb5_enctype kerberos_enctype_bitmap_to_enctype(uint32_t enctype_bitmap)
929{
930 switch (enctype_bitmap) {
931 case ENC_CRC32:
932 return ENCTYPE_DES_CBC_CRC;
933 case ENC_RSA_MD5:
934 return ENCTYPE_DES_CBC_MD5;
935 case ENC_RC4_HMAC_MD5:
936 return ENCTYPE_ARCFOUR_HMAC_MD5;
937 case ENC_HMAC_SHA1_96_AES128:
938 return ENCTYPE_AES128_CTS_HMAC_SHA1_96;
939 case ENC_HMAC_SHA1_96_AES256:
940 return ENCTYPE_AES256_CTS_HMAC_SHA1_96;
941 default:
942 return 0;
943 }
944}
945
946/* Return an array of krb5_enctype values */
947krb5_error_code kerberos_enctype_bitmap_to_enctypes(TALLOC_CTX *mem_ctx, uint32_t enctype_bitmap, krb5_enctype **enctypes)
948{
949 unsigned int i, j = 0;
950 *enctypes = talloc_zero_array(mem_ctx, krb5_enctype, (8*sizeof(enctype_bitmap))+1);
951 if (!*enctypes) {
952 return ENOMEM;
953 }
954 for (i=0; i<(8*sizeof(enctype_bitmap)); i++) {
955 uint32_t bit_value = (1 << i) & enctype_bitmap;
956 if (bit_value & enctype_bitmap) {
957 (*enctypes)[j] = kerberos_enctype_bitmap_to_enctype(bit_value);
958 if (!(*enctypes)[j]) {
959 continue;
960 }
961 j++;
962 }
963 }
964 (*enctypes)[j] = 0;
965 return 0;
966}
Note: See TracBrowser for help on using the repository browser.