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"
31 struct principal_container {
32 struct smb_krb5_context *smb_krb5_context;
33 krb5_principal principal;
36 static krb5_error_code free_principal(struct principal_container *pc)
38 /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
39 krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
45 static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
46 const char *princ_string,
47 struct smb_krb5_context *smb_krb5_context,
48 krb5_principal *princ,
49 const char **error_string)
52 struct principal_container *mem_ctx;
53 if (princ_string == NULL) {
58 ret = krb5_parse_name(smb_krb5_context->krb5_context,
62 (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
66 mem_ctx = talloc(parent_ctx, struct principal_container);
68 (*error_string) = error_message(ENOMEM);
72 /* This song-and-dance effectivly puts the principal
73 * into talloc, so we can't loose it. */
74 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
75 mem_ctx->principal = *princ;
76 talloc_set_destructor(mem_ctx, free_principal);
80 static krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx,
81 struct cli_credentials *machine_account,
82 struct smb_krb5_context *smb_krb5_context,
83 krb5_principal *salt_princ)
86 char *machine_username;
89 const char *salt_principal;
90 const char *error_string;
91 struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
96 salt_principal = cli_credentials_get_salt_principal(machine_account);
98 ret = parse_principal(parent_ctx, salt_principal, smb_krb5_context, salt_princ, &error_string);
100 machine_username = talloc_strdup(mem_ctx, cli_credentials_get_username(machine_account));
102 if (!machine_username) {
103 talloc_free(mem_ctx);
107 if (machine_username[strlen(machine_username)-1] == '$') {
108 machine_username[strlen(machine_username)-1] = '\0';
110 lower_realm = strlower_talloc(mem_ctx, cli_credentials_get_realm(machine_account));
112 talloc_free(mem_ctx);
116 salt_body = talloc_asprintf(mem_ctx, "%s.%s", machine_username,
119 talloc_free(mem_ctx);
123 ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
124 cli_credentials_get_realm(machine_account),
125 "host", salt_body, NULL);
127 /* This song-and-dance effectivly puts the principal
128 * into talloc, so we can't loose it. */
129 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
130 mem_ctx->principal = *salt_princ;
131 talloc_set_destructor(mem_ctx, free_principal);
138 /* Obtain the principal set on this context. Requires a
139 * smb_krb5_context because we are doing krb5 principal parsing with
140 * the library routines. The returned princ is placed in the talloc
141 * system by means of a destructor (do *not* free). */
143 krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
144 struct cli_credentials *credentials,
145 struct smb_krb5_context *smb_krb5_context,
146 krb5_principal *princ,
147 enum credentials_obtained *obtained,
148 const char **error_string)
151 const char *princ_string;
152 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
154 (*error_string) = error_message(ENOMEM);
157 princ_string = cli_credentials_get_principal_and_obtained(credentials, mem_ctx, obtained);
159 (*error_string) = error_message(ENOMEM);
163 ret = parse_principal(parent_ctx, princ_string,
164 smb_krb5_context, princ, error_string);
165 talloc_free(mem_ctx);
169 /* Obtain the principal set on this context. Requires a
170 * smb_krb5_context because we are doing krb5 principal parsing with
171 * the library routines. The returned princ is placed in the talloc
172 * system by means of a destructor (do *not* free). */
174 krb5_error_code impersonate_principal_from_credentials(TALLOC_CTX *parent_ctx,
175 struct cli_credentials *credentials,
176 struct smb_krb5_context *smb_krb5_context,
177 krb5_principal *princ,
178 const char **error_string)
180 return parse_principal(parent_ctx, cli_credentials_get_impersonate_principal(credentials),
181 smb_krb5_context, princ, error_string);
185 * Return a freshly allocated ccache (destroyed by destructor on child
186 * of parent_ctx), for a given set of client credentials
189 krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
190 struct cli_credentials *credentials,
191 struct smb_krb5_context *smb_krb5_context,
193 enum credentials_obtained *obtained,
194 const char **error_string)
197 const char *password, *target_service;
199 krb5_principal princ;
200 krb5_principal impersonate_principal;
202 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
205 (*error_string) = strerror(ENOMEM);
209 ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
211 talloc_free(mem_ctx);
215 ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
217 talloc_free(mem_ctx);
221 target_service = cli_credentials_get_target_service(credentials);
223 password = cli_credentials_get_password(credentials);
228 ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
230 impersonate_principal, target_service,
232 } else if (impersonate_principal) {
233 (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock. A password must be specified in the credentials";
236 /* No password available, try to use a keyblock instead */
238 krb5_keyblock keyblock;
239 const struct samr_Password *mach_pwd;
240 mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
242 talloc_free(mem_ctx);
243 (*error_string) = "kinit_to_ccache: No password available for kinit\n";
246 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
247 ENCTYPE_ARCFOUR_HMAC,
248 mach_pwd->hash, sizeof(mach_pwd->hash),
252 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
256 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
260 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
261 /* Perhaps we have been given an invalid skew, so try again without it */
262 time_t t = time(NULL);
263 krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
265 /* not a skew problem */
270 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
271 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
272 cli_credentials_get_principal(credentials, mem_ctx),
273 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
275 talloc_free(mem_ctx);
279 /* cope with ticket being in the future due to clock skew */
280 if ((unsigned)kdc_time > time(NULL)) {
281 time_t t = time(NULL);
282 int time_offset =(unsigned)kdc_time-t;
283 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
284 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
287 if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
288 ret = kinit_to_ccache(parent_ctx,
295 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
296 cli_credentials_get_principal(credentials, mem_ctx),
297 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
299 talloc_free(mem_ctx);
302 talloc_free(mem_ctx);
306 static krb5_error_code free_keytab(struct keytab_container *ktc)
308 return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
311 krb5_error_code smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
312 struct smb_krb5_context *smb_krb5_context,
313 const char *keytab_name, struct keytab_container **ktc)
317 ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
319 DEBUG(1,("failed to open krb5 keytab: %s\n",
320 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
325 *ktc = talloc(mem_ctx, struct keytab_container);
330 (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
331 (*ktc)->keytab = keytab;
332 talloc_set_destructor(*ktc, free_keytab);
337 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
338 const char *princ_string,
339 krb5_principal princ,
340 krb5_principal salt_princ,
342 const char *password_s,
343 struct smb_krb5_context *smb_krb5_context,
344 const char **enctype_strings,
350 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
355 password.data = discard_const_p(char *, password_s);
356 password.length = strlen(password_s);
358 for (i=0; enctype_strings[i]; i++) {
359 krb5_keytab_entry entry;
360 krb5_enctype enctype;
361 ret = krb5_string_to_enctype(smb_krb5_context->krb5_context, enctype_strings[i], &enctype);
363 DEBUG(1, ("Failed to interpret %s as a krb5 encryption type: %s\n",
365 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
367 talloc_free(mem_ctx);
370 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
371 salt_princ, &password, &entry.keyblock, enctype);
373 talloc_free(mem_ctx);
377 entry.principal = princ;
379 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
381 DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
385 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
387 talloc_free(mem_ctx);
388 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
392 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
394 enctype_strings[i]));
396 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
398 talloc_free(mem_ctx);
402 static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
403 struct cli_credentials *machine_account,
404 struct smb_krb5_context *smb_krb5_context,
405 const char **enctype_strings,
410 const char *password_s;
411 const char *old_secret;
413 krb5_principal salt_princ;
414 krb5_principal princ;
415 const char *princ_string;
416 const char *error_string;
417 enum credentials_obtained obtained;
419 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
424 princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
425 /* Get the principal we will store the new keytab entries under */
426 ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ, &obtained, &error_string);
428 DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n", error_string));
429 talloc_free(mem_ctx);
433 /* The salt used to generate these entries may be different however, fetch that */
434 ret = salt_principal_from_credentials(mem_ctx, machine_account,
438 DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
439 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
441 talloc_free(mem_ctx);
445 /* Finally, do the dance to get the password to put in the entry */
446 password_s = cli_credentials_get_password(machine_account);
448 krb5_keytab_entry entry;
449 const struct samr_Password *mach_pwd;
451 if (!str_list_check(enctype_strings, "arcfour-hmac-md5")) {
452 DEBUG(1, ("Asked to create keytab, but with only an NT hash supplied, "
453 "but not listing arcfour-hmac-md5 as an enc type to include in the keytab!\n"));
454 talloc_free(mem_ctx);
458 /* If we don't have the plaintext password, try for
459 * the MD4 password hash */
460 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
462 /* OK, nothing to do here */
463 talloc_free(mem_ctx);
466 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
467 ETYPE_ARCFOUR_HMAC_MD5,
468 mach_pwd->hash, sizeof(mach_pwd->hash),
471 DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
472 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
474 talloc_free(mem_ctx);
478 entry.principal = princ;
479 entry.vno = cli_credentials_get_kvno(machine_account);
480 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
482 DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
483 cli_credentials_get_principal(machine_account, mem_ctx),
484 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
486 talloc_free(mem_ctx);
487 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
491 DEBUG(5, ("Added %s(kvno %d) to keytab (arcfour-hmac-md5)\n",
492 cli_credentials_get_principal(machine_account, mem_ctx),
493 cli_credentials_get_kvno(machine_account)));
495 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
497 /* Can't go any further, we only have this one key */
498 talloc_free(mem_ctx);
502 kvno = cli_credentials_get_kvno(machine_account);
503 /* good, we actually have the real plaintext */
504 ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
505 kvno, password_s, smb_krb5_context,
506 enctype_strings, keytab);
508 talloc_free(mem_ctx);
512 if (!add_old || kvno == 0) {
513 talloc_free(mem_ctx);
517 old_secret = cli_credentials_get_old_password(machine_account);
519 talloc_free(mem_ctx);
523 ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
524 kvno - 1, old_secret, smb_krb5_context,
525 enctype_strings, keytab);
527 talloc_free(mem_ctx);
531 talloc_free(mem_ctx);
537 * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
539 * These entries are now stale, we only keep the current, and previous entries around.
541 * Inspired by the code in Samba3 for 'use kerberos keytab'.
545 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
546 struct cli_credentials *machine_account,
547 struct smb_krb5_context *smb_krb5_context,
548 krb5_keytab keytab, bool *found_previous)
550 krb5_error_code ret, ret2;
551 krb5_kt_cursor cursor;
552 krb5_principal princ;
554 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
555 const char *princ_string;
556 const char *error_string;
557 enum credentials_obtained obtained;
563 *found_previous = false;
564 princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
566 /* Get the principal we will store the new keytab entries under */
567 ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ, &obtained, &error_string);
569 DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n", error_string));
570 talloc_free(mem_ctx);
574 kvno = cli_credentials_get_kvno(machine_account);
576 /* for each entry in the keytab */
577 ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
581 case HEIM_ERR_OPNOTSUPP:
584 /* no point enumerating if there isn't anything here */
585 talloc_free(mem_ctx);
588 DEBUG(1,("failed to open keytab for read of old entries: %s\n",
589 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
591 talloc_free(mem_ctx);
596 krb5_keytab_entry entry;
597 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
601 /* if it matches our principal */
602 if (!krb5_kt_compare(smb_krb5_context->krb5_context, &entry, princ, 0, 0)) {
603 /* Free the entry, it wasn't the one we were looking for anyway */
604 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
608 /* delete it, if it is not kvno -1 */
609 if (entry.vno != (kvno - 1 )) {
610 /* Release the enumeration. We are going to
611 * have to start this from the top again,
612 * because deletes during enumeration may not
613 * always be consistant.
615 * Also, the enumeration locks a FILE: keytab
618 krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
620 ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
621 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
623 /* Deleted: Restart from the top */
624 ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
626 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
627 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
628 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
631 talloc_free(mem_ctx);
640 *found_previous = true;
643 /* Free the entry, we don't need it any more */
644 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
648 krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
658 DEBUG(1,("failed in deleting old entries for principal: %s: %s\n",
660 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
663 talloc_free(mem_ctx);
667 krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
668 struct cli_credentials *machine_account,
669 struct smb_krb5_context *smb_krb5_context,
670 const char **enctype_strings,
671 struct keytab_container *keytab_container)
675 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
680 ret = remove_old_entries(mem_ctx, machine_account,
681 smb_krb5_context, keytab_container->keytab, &found_previous);
683 talloc_free(mem_ctx);
687 /* Create a new keytab. If during the cleanout we found
688 * entires for kvno -1, then don't try and duplicate them.
689 * Otherwise, add kvno, and kvno -1 */
691 ret = create_keytab(mem_ctx, machine_account, smb_krb5_context,
693 keytab_container->keytab,
694 found_previous ? false : true);
695 talloc_free(mem_ctx);
699 krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
700 struct cli_credentials *machine_account,
701 struct smb_krb5_context *smb_krb5_context,
702 const char **enctype_strings,
703 struct keytab_container **keytab_container)
706 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
707 const char *rand_string;
708 const char *keytab_name;
713 *keytab_container = talloc(mem_ctx, struct keytab_container);
715 rand_string = generate_random_str(mem_ctx, 16);
717 talloc_free(mem_ctx);
721 keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
724 talloc_free(mem_ctx);
728 ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
733 ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, enctype_strings, *keytab_container);
735 talloc_steal(parent_ctx, *keytab_container);
737 *keytab_container = NULL;
739 talloc_free(mem_ctx);
743 /* Translate between the IETF encryption type values and the Microsoft msDS-SupportedEncryptionTypes values */
744 uint32_t kerberos_enctype_to_bitmap(krb5_enctype enc_type_enum)
746 switch (enc_type_enum) {
747 case ENCTYPE_DES_CBC_CRC:
749 case ENCTYPE_DES_CBC_MD5:
751 case ENCTYPE_ARCFOUR_HMAC_MD5:
752 return ENC_RC4_HMAC_MD5;
753 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
754 return ENC_HMAC_SHA1_96_AES128;
755 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
756 return ENC_HMAC_SHA1_96_AES256;
762 /* Translate between the Microsoft msDS-SupportedEncryptionTypes values and the IETF encryption type values */
763 krb5_enctype kerberos_enctype_bitmap_to_enctype(uint32_t enctype_bitmap)
765 switch (enctype_bitmap) {
767 return ENCTYPE_DES_CBC_CRC;
769 return ENCTYPE_DES_CBC_MD5;
770 case ENC_RC4_HMAC_MD5:
771 return ENCTYPE_ARCFOUR_HMAC_MD5;
772 case ENC_HMAC_SHA1_96_AES128:
773 return ENCTYPE_AES128_CTS_HMAC_SHA1_96;
774 case ENC_HMAC_SHA1_96_AES256:
775 return ENCTYPE_AES256_CTS_HMAC_SHA1_96;
781 /* Return an array of krb5_enctype values */
782 krb5_error_code kerberos_enctype_bitmap_to_enctypes(TALLOC_CTX *mem_ctx, uint32_t enctype_bitmap, krb5_enctype **enctypes)
784 unsigned int i, j = 0;
785 *enctypes = talloc_zero_array(mem_ctx, krb5_enctype, 8*sizeof(enctype_bitmap));
789 for (i=0; i<(8*sizeof(enctype_bitmap)); i++) {
790 if ((1 << i) & enctype_bitmap) {
791 (*enctypes)[j] = kerberos_enctype_bitmap_to_enctype(enctype_bitmap);
792 if (!(*enctypes)[j]) {
793 return KRB5_PROG_ETYPE_NOSUPP;