2 Unix SMB/CIFS implementation.
4 Kerberos utility functions for GENSEC
6 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
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.
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.
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/>.
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"
32 struct principal_container {
33 struct smb_krb5_context *smb_krb5_context;
34 krb5_principal principal;
35 const char *string_form; /* Optional */
38 static krb5_error_code free_principal(struct principal_container *pc)
40 /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
41 krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
47 static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
48 const char *princ_string,
49 struct smb_krb5_context *smb_krb5_context,
50 krb5_principal *princ,
51 const char **error_string)
54 struct principal_container *mem_ctx;
55 if (princ_string == NULL) {
60 ret = krb5_parse_name(smb_krb5_context->krb5_context,
64 (*error_string) = smb_get_krb5_error_message(
65 smb_krb5_context->krb5_context,
70 mem_ctx = talloc(parent_ctx, struct principal_container);
72 (*error_string) = error_message(ENOMEM);
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,
80 mem_ctx->principal = *princ;
81 talloc_set_destructor(mem_ctx, free_principal);
85 /* Obtain the principal set on this context. Requires a
86 * smb_krb5_context because we are doing krb5 principal parsing with
87 * the library routines. The returned princ is placed in the talloc
88 * system by means of a destructor (do *not* free). */
90 krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
91 struct cli_credentials *credentials,
92 struct smb_krb5_context *smb_krb5_context,
93 krb5_principal *princ,
94 enum credentials_obtained *obtained,
95 const char **error_string)
98 const char *princ_string;
99 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
100 *obtained = CRED_UNINITIALISED;
103 (*error_string) = error_message(ENOMEM);
106 princ_string = cli_credentials_get_principal_and_obtained(credentials,
114 ret = parse_principal(parent_ctx, princ_string,
115 smb_krb5_context, princ, error_string);
116 talloc_free(mem_ctx);
120 /* Obtain the principal set on this context. Requires a
121 * smb_krb5_context because we are doing krb5 principal parsing with
122 * the library routines. The returned princ is placed in the talloc
123 * system by means of a destructor (do *not* free). */
125 static krb5_error_code impersonate_principal_from_credentials(
126 TALLOC_CTX *parent_ctx,
127 struct cli_credentials *credentials,
128 struct smb_krb5_context *smb_krb5_context,
129 krb5_principal *princ,
130 const char **error_string)
132 return parse_principal(parent_ctx,
133 cli_credentials_get_impersonate_principal(credentials),
134 smb_krb5_context, princ, error_string);
137 krb5_error_code smb_krb5_create_principals_array(TALLOC_CTX *mem_ctx,
138 krb5_context context,
139 const char *account_name,
143 uint32_t *pnum_principals,
144 krb5_principal **pprincipals,
145 const char **error_string)
147 krb5_error_code code;
149 uint32_t num_principals = 0;
150 krb5_principal *principals;
153 tmp_ctx = talloc_new(mem_ctx);
154 if (tmp_ctx == NULL) {
155 *error_string = "Cannot allocate tmp_ctx";
160 *error_string = "Cannot create principal without a realm";
165 if (account_name == NULL && (num_spns == 0 || spns == NULL)) {
166 *error_string = "Cannot create principal without an account or SPN";
171 if (account_name != NULL && account_name[0] != '\0') {
174 num_principals += num_spns;
176 principals = talloc_zero_array(tmp_ctx,
179 if (principals == NULL) {
180 *error_string = "Cannot allocate principals";
185 for (i = 0; i < num_spns; i++) {
186 code = krb5_parse_name(context, spns[i], &(principals[i]));
188 *error_string = smb_get_krb5_error_message(context,
195 if (account_name != NULL && account_name[0] != '\0') {
196 code = smb_krb5_make_principal(context,
202 *error_string = smb_get_krb5_error_message(context,
209 if (pnum_principals != NULL) {
210 *pnum_principals = num_principals;
212 if (pprincipals != NULL) {
213 *pprincipals = talloc_steal(mem_ctx, principals);
219 talloc_free(tmp_ctx);
224 * Return a freshly allocated ccache (destroyed by destructor on child
225 * of parent_ctx), for a given set of client credentials
228 krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
229 struct cli_credentials *credentials,
230 struct smb_krb5_context *smb_krb5_context,
231 struct tevent_context *event_ctx,
233 enum credentials_obtained *obtained,
234 const char **error_string)
237 const char *password;
238 #ifdef SAMBA4_USES_HEIMDAL
239 const char *self_service;
241 const char *target_service;
243 krb5_principal princ;
244 krb5_principal impersonate_principal;
246 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
247 krb5_get_init_creds_opt *krb_options;
250 (*error_string) = strerror(ENOMEM);
254 ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
256 talloc_free(mem_ctx);
261 (*error_string) = talloc_asprintf(credentials, "principal, username or realm was not specified in the credentials");
262 talloc_free(mem_ctx);
263 return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
266 ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
268 talloc_free(mem_ctx);
272 #ifdef SAMBA4_USES_HEIMDAL
273 self_service = cli_credentials_get_self_service(credentials);
275 target_service = cli_credentials_get_target_service(credentials);
277 password = cli_credentials_get_password(credentials);
279 /* setup the krb5 options we want */
280 if ((ret = krb5_get_init_creds_opt_alloc(smb_krb5_context->krb5_context, &krb_options))) {
281 (*error_string) = talloc_asprintf(credentials, "krb5_get_init_creds_opt_alloc failed (%s)\n",
282 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
284 talloc_free(mem_ctx);
288 #ifdef SAMBA4_USES_HEIMDAL /* Disable for now MIT reads defaults when needed */
289 /* get the defaults */
290 krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
292 /* set if we want a forwardable ticket */
293 switch (cli_credentials_get_krb_forwardable(credentials)) {
294 case CRED_AUTO_KRB_FORWARDABLE:
296 case CRED_NO_KRB_FORWARDABLE:
297 krb5_get_init_creds_opt_set_forwardable(krb_options, FALSE);
299 case CRED_FORCE_KRB_FORWARDABLE:
300 krb5_get_init_creds_opt_set_forwardable(krb_options, TRUE);
304 #ifdef SAMBA4_USES_HEIMDAL /* FIXME: MIT does not have this yet */
306 * In order to work against windows KDCs even if we use
307 * the netbios domain name as realm, we need to add the following
309 * KRB5_INIT_CREDS_NO_C_CANON_CHECK;
310 * KRB5_INIT_CREDS_NO_C_NO_EKU_CHECK;
312 * On MIT: Set pkinit_eku_checking to none
314 krb5_get_init_creds_opt_set_win2k(smb_krb5_context->krb5_context,
317 krb5_get_init_creds_opt_set_canonicalize(krb_options, true);
322 #ifdef SAMBA4_USES_HEIMDAL
323 struct tevent_context *previous_ev;
324 /* Do this every time, in case we have weird recursive issues here */
325 ret = smb_krb5_context_set_event_ctx(smb_krb5_context, event_ctx, &previous_ev);
327 talloc_free(mem_ctx);
332 if (impersonate_principal) {
333 #ifdef SAMBA4_USES_HEIMDAL
334 ret = kerberos_kinit_s4u2_cc(
335 smb_krb5_context->krb5_context,
336 ccache, princ, password,
337 impersonate_principal,
338 self_service, target_service,
339 krb_options, NULL, &kdc_time);
341 talloc_free(mem_ctx);
342 (*error_string) = "INTERNAL error: s4u2 ops "
343 "are not supported with MIT build yet";
347 ret = kerberos_kinit_password_cc(
348 smb_krb5_context->krb5_context,
349 ccache, princ, password,
351 krb_options, NULL, &kdc_time);
353 } else if (impersonate_principal) {
354 talloc_free(mem_ctx);
355 (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock. A password must be specified in the credentials";
358 /* No password available, try to use a keyblock instead */
360 krb5_keyblock keyblock;
361 const struct samr_Password *mach_pwd;
362 mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
364 talloc_free(mem_ctx);
365 (*error_string) = "kinit_to_ccache: No password available for kinit\n";
366 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
367 #ifdef SAMBA4_USES_HEIMDAL
368 smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
372 ret = smb_krb5_keyblock_init_contents(smb_krb5_context->krb5_context,
373 ENCTYPE_ARCFOUR_HMAC,
374 mach_pwd->hash, sizeof(mach_pwd->hash),
378 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
380 target_service, krb_options,
382 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
386 #ifdef SAMBA4_USES_HEIMDAL
387 smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
390 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
391 /* Perhaps we have been given an invalid skew, so try again without it */
392 time_t t = time(NULL);
393 krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
395 /* not a skew problem */
400 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
402 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
403 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
404 cli_credentials_get_principal(credentials, mem_ctx),
405 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
407 talloc_free(mem_ctx);
411 /* cope with ticket being in the future due to clock skew */
412 if ((unsigned)kdc_time > time(NULL)) {
413 time_t t = time(NULL);
414 int time_offset =(unsigned)kdc_time-t;
415 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
416 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
419 if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
420 ret = kinit_to_ccache(parent_ctx,
429 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
430 cli_credentials_get_principal(credentials, mem_ctx),
431 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
433 talloc_free(mem_ctx);
437 DEBUG(10,("kinit for %s succeeded\n",
438 cli_credentials_get_principal(credentials, mem_ctx)));
441 talloc_free(mem_ctx);
445 static krb5_error_code free_keytab_container(struct keytab_container *ktc)
447 return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
450 krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
451 struct smb_krb5_context *smb_krb5_context,
452 krb5_keytab opt_keytab,
453 const char *keytab_name,
454 struct keytab_container **ktc)
462 ret = krb5_kt_resolve(smb_krb5_context->krb5_context,
463 keytab_name, &keytab);
465 DEBUG(1,("failed to open krb5 keytab: %s\n",
466 smb_get_krb5_error_message(
467 smb_krb5_context->krb5_context,
473 *ktc = talloc(mem_ctx, struct keytab_container);
478 (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
479 (*ktc)->keytab = keytab;
480 (*ktc)->password_based = false;
481 talloc_set_destructor(*ktc, free_keytab_container);
487 * Walk the keytab, looking for entries of this principal name,
488 * with KVNO other than current kvno -1.
490 * These entries are now stale,
491 * we only keep the current and previous entries around.
493 * Inspired by the code in Samba3 for 'use kerberos keytab'.
495 krb5_error_code smb_krb5_remove_obsolete_keytab_entries(TALLOC_CTX *mem_ctx,
496 krb5_context context,
498 uint32_t num_principals,
499 krb5_principal *principals,
501 bool *found_previous,
502 const char **error_string)
505 krb5_error_code code;
506 krb5_kt_cursor cursor;
508 tmp_ctx = talloc_new(mem_ctx);
509 if (tmp_ctx == NULL) {
510 *error_string = "Cannot allocate tmp_ctx";
514 *found_previous = true;
516 code = krb5_kt_start_seq_get(context, keytab, &cursor);
520 #ifdef HEIM_ERR_OPNOTSUPP
521 case HEIM_ERR_OPNOTSUPP:
525 /* no point enumerating if there isn't anything here */
529 *error_string = talloc_asprintf(mem_ctx,
530 "failed to open keytab for read of old entries: %s\n",
531 smb_get_krb5_error_message(context, code, mem_ctx));
536 krb5_kvno old_kvno = kvno - 1;
537 krb5_keytab_entry entry;
538 bool matched = false;
541 code = krb5_kt_next_entry(context, keytab, &entry, &cursor);
546 for (i = 0; i < num_principals; i++) {
549 ok = smb_krb5_kt_compare(context,
562 * Free the entry, it wasn't the one we were looking
565 krb5_kt_free_entry(context, &entry);
566 /* Make sure we do not double free */
572 * Delete it, if it is not kvno - 1.
574 * Some keytab files store the kvno only in 8bits. Limit the
575 * compare to 8bits, so that we don't miss old keys and delete
578 if ((entry.vno & 0xff) != (old_kvno & 0xff)) {
581 /* Release the enumeration. We are going to
582 * have to start this from the top again,
583 * because deletes during enumeration may not
584 * always be consistent.
586 * Also, the enumeration locks a FILE: keytab
588 krb5_kt_end_seq_get(context, keytab, &cursor);
590 code = krb5_kt_remove_entry(context, keytab, &entry);
591 krb5_kt_free_entry(context, &entry);
593 /* Make sure we do not double free */
596 /* Deleted: Restart from the top */
597 rc = krb5_kt_start_seq_get(context, keytab, &cursor);
599 krb5_kt_free_entry(context, &entry);
601 /* Make sure we do not double free */
604 DEBUG(1, ("failed to restart enumeration of keytab: %s\n",
605 smb_get_krb5_error_message(context,
609 talloc_free(tmp_ctx);
618 *found_previous = true;
621 /* Free the entry, we don't need it any more */
622 krb5_kt_free_entry(context, &entry);
623 /* Make sure we do not double free */
627 krb5_kt_end_seq_get(context, keytab, &cursor);
637 *error_string = talloc_asprintf(mem_ctx,
638 "failed in deleting old entries for principal: %s\n",
639 smb_get_krb5_error_message(context,
646 talloc_free(tmp_ctx);