2 Unix SMB/CIFS implementation.
3 kerberos utility library
4 Copyright (C) Andrew Tridgell 2001
5 Copyright (C) Remus Koos 2001
6 Copyright (C) Luke Howard 2003
7 Copyright (C) Guenther Deschner 2003, 2005
8 Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
9 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 2 of the License, or
14 (at your option) any later version.
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with this program; if not, write to the Free Software
23 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30 #if !defined(HAVE_KRB5_PRINC_COMPONENT)
31 const krb5_data *krb5_princ_component(krb5_context, krb5_principal, int );
34 /**********************************************************************************
35 Try to verify a ticket using the system keytab... the system keytab has kvno -1 entries, so
36 it's more like what microsoft does... see comment in utils/net_ads.c in the
37 ads_keytab_add_entry function for details.
38 ***********************************************************************************/
40 static BOOL ads_keytab_verify_ticket(krb5_context context, krb5_auth_context auth_context,
41 const DATA_BLOB *ticket, krb5_data *p_packet, krb5_ticket **pp_tkt,
42 krb5_keyblock **keyblock)
44 krb5_error_code ret = 0;
46 krb5_keytab keytab = NULL;
47 krb5_kt_cursor kt_cursor;
48 krb5_keytab_entry kt_entry;
49 char *valid_princ_formats[7] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL };
50 char *entry_princ_s = NULL;
51 fstring my_name, my_fqdn;
53 int number_matched_principals = 0;
55 /* Generate the list of principal names which we expect
56 * clients might want to use for authenticating to the file
57 * service. We allow name$,{host,cifs}/{name,fqdn,name.REALM}. */
59 fstrcpy(my_name, global_myname());
62 name_to_fqdn(my_fqdn, global_myname());
64 asprintf(&valid_princ_formats[0], "%s$@%s", my_name, lp_realm());
65 asprintf(&valid_princ_formats[1], "host/%s@%s", my_name, lp_realm());
66 asprintf(&valid_princ_formats[2], "host/%s@%s", my_fqdn, lp_realm());
67 asprintf(&valid_princ_formats[3], "host/%s.%s@%s", my_name, lp_realm(), lp_realm());
68 asprintf(&valid_princ_formats[4], "cifs/%s@%s", my_name, lp_realm());
69 asprintf(&valid_princ_formats[5], "cifs/%s@%s", my_fqdn, lp_realm());
70 asprintf(&valid_princ_formats[6], "cifs/%s.%s@%s", my_name, lp_realm(), lp_realm());
72 ZERO_STRUCT(kt_entry);
73 ZERO_STRUCT(kt_cursor);
75 ret = krb5_kt_default(context, &keytab);
77 DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_default failed (%s)\n", error_message(ret)));
81 /* Iterate through the keytab. For each key, if the principal
82 * name case-insensitively matches one of the allowed formats,
83 * try verifying the ticket using that principal. */
85 ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
87 DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_start_seq_get failed (%s)\n", error_message(ret)));
91 if (ret != KRB5_KT_END && ret != ENOENT ) {
92 while (!auth_ok && (krb5_kt_next_entry(context, keytab, &kt_entry, &kt_cursor) == 0)) {
93 ret = smb_krb5_unparse_name(context, kt_entry.principal, &entry_princ_s);
95 DEBUG(1, ("ads_keytab_verify_ticket: smb_krb5_unparse_name failed (%s)\n",
100 for (i = 0; i < sizeof(valid_princ_formats) / sizeof(valid_princ_formats[0]); i++) {
101 if (strequal(entry_princ_s, valid_princ_formats[i])) {
102 number_matched_principals++;
103 p_packet->length = ticket->length;
104 p_packet->data = (krb5_pointer)ticket->data;
107 ret = krb5_rd_req_return_keyblock_from_keytab(context, &auth_context, p_packet,
108 kt_entry.principal, keytab,
109 NULL, pp_tkt, keyblock);
112 DEBUG(10,("ads_keytab_verify_ticket: "
113 "krb5_rd_req_return_keyblock_from_keytab(%s) failed: %s\n",
114 entry_princ_s, error_message(ret)));
116 /* workaround for MIT:
117 * as krb5_ktfile_get_entry will
118 * explicitly close the
119 * krb5_keytab as soon as
120 * krb5_rd_req has sucessfully
121 * decrypted the ticket but the
122 * ticket is not valid yet (due
123 * to clockskew) there is no
124 * point in querying more
125 * keytab entries - Guenther */
127 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
128 ret == KRB5KRB_AP_ERR_TKT_EXPIRED) {
132 DEBUG(3,("ads_keytab_verify_ticket: "
133 "krb5_rd_req_return_keyblock_from_keytab succeeded for principal %s\n",
141 /* Free the name we parsed. */
142 SAFE_FREE(entry_princ_s);
144 /* Free the entry we just read. */
145 smb_krb5_kt_free_entry(context, &kt_entry);
146 ZERO_STRUCT(kt_entry);
148 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
151 ZERO_STRUCT(kt_cursor);
155 for (i = 0; i < sizeof(valid_princ_formats) / sizeof(valid_princ_formats[0]); i++) {
156 SAFE_FREE(valid_princ_formats[i]);
160 if (!number_matched_principals) {
161 DEBUG(3, ("ads_keytab_verify_ticket: no keytab principals matched expected file service name.\n"));
163 DEBUG(3, ("ads_keytab_verify_ticket: krb5_rd_req failed for all %d matched keytab principals\n",
164 number_matched_principals));
168 SAFE_FREE(entry_princ_s);
171 krb5_keytab_entry zero_kt_entry;
172 ZERO_STRUCT(zero_kt_entry);
173 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
174 smb_krb5_kt_free_entry(context, &kt_entry);
179 krb5_kt_cursor zero_csr;
180 ZERO_STRUCT(zero_csr);
181 if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
182 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
187 krb5_kt_close(context, keytab);
192 /**********************************************************************************
193 Try to verify a ticket using the secrets.tdb.
194 ***********************************************************************************/
196 static BOOL ads_secrets_verify_ticket(krb5_context context, krb5_auth_context auth_context,
197 krb5_principal host_princ,
198 const DATA_BLOB *ticket, krb5_data *p_packet, krb5_ticket **pp_tkt,
199 krb5_keyblock **keyblock)
201 krb5_error_code ret = 0;
202 BOOL auth_ok = False;
203 char *password_s = NULL;
205 krb5_enctype enctypes[4] = { ENCTYPE_DES_CBC_CRC, ENCTYPE_DES_CBC_MD5, 0, 0 };
208 #if defined(ENCTYPE_ARCFOUR_HMAC)
209 enctypes[2] = ENCTYPE_ARCFOUR_HMAC;
212 ZERO_STRUCTP(keyblock);
214 if (!secrets_init()) {
215 DEBUG(1,("ads_secrets_verify_ticket: secrets_init failed\n"));
219 password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
221 DEBUG(1,("ads_secrets_verify_ticket: failed to fetch machine password\n"));
225 password.data = password_s;
226 password.length = strlen(password_s);
228 /* CIFS doesn't use addresses in tickets. This would break NAT. JRA */
230 p_packet->length = ticket->length;
231 p_packet->data = (krb5_pointer)ticket->data;
233 /* We need to setup a auth context with each possible encoding type in turn. */
234 for (i=0;enctypes[i];i++) {
235 krb5_keyblock *key = NULL;
237 if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
241 if (create_kerberos_key_from_string(context, host_princ, &password, key, enctypes[i])) {
246 krb5_auth_con_setuseruserkey(context, auth_context, key);
248 if (!(ret = krb5_rd_req(context, &auth_context, p_packet,
250 NULL, NULL, pp_tkt))) {
251 DEBUG(10,("ads_secrets_verify_ticket: enc type [%u] decrypted message !\n",
252 (unsigned int)enctypes[i] ));
254 krb5_copy_keyblock(context, key, keyblock);
255 krb5_free_keyblock(context, key);
259 DEBUG((ret != KRB5_BAD_ENCTYPE) ? 3 : 10,
260 ("ads_secrets_verify_ticket: enc type [%u] failed to decrypt with error %s\n",
261 (unsigned int)enctypes[i], error_message(ret)));
263 /* successfully decrypted but ticket is just not valid at the moment */
264 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
265 ret == KRB5KRB_AP_ERR_TKT_EXPIRED) {
269 krb5_free_keyblock(context, key);
274 SAFE_FREE(password_s);
279 /**********************************************************************************
280 Verify an incoming ticket and parse out the principal name and
281 authorization_data if available.
282 ***********************************************************************************/
284 NTSTATUS ads_verify_ticket(TALLOC_CTX *mem_ctx,
285 const char *realm, time_t time_offset,
286 const DATA_BLOB *ticket,
287 char **principal, PAC_DATA **pac_data,
289 DATA_BLOB *session_key)
291 NTSTATUS sret = NT_STATUS_LOGON_FAILURE;
294 krb5_context context = NULL;
295 krb5_auth_context auth_context = NULL;
297 krb5_ticket *tkt = NULL;
298 krb5_rcache rcache = NULL;
299 krb5_keyblock *keyblock = NULL;
303 krb5_principal host_princ = NULL;
304 krb5_const_principal client_principal = NULL;
305 char *host_princ_s = NULL;
306 BOOL got_replay_mutex = False;
308 BOOL auth_ok = False;
309 BOOL got_auth_data = False;
312 ZERO_STRUCT(auth_data);
313 ZERO_STRUCTP(ap_rep);
314 ZERO_STRUCTP(session_key);
316 initialize_krb5_error_table();
317 ret = krb5_init_context(&context);
319 DEBUG(1,("ads_verify_ticket: krb5_init_context failed (%s)\n", error_message(ret)));
320 return NT_STATUS_LOGON_FAILURE;
323 if (time_offset != 0) {
324 krb5_set_real_time(context, time(NULL) + time_offset, 0);
327 ret = krb5_set_default_realm(context, realm);
329 DEBUG(1,("ads_verify_ticket: krb5_set_default_realm failed (%s)\n", error_message(ret)));
333 /* This whole process is far more complex than I would
334 like. We have to go through all this to allow us to store
335 the secret internally, instead of using /etc/krb5.keytab */
337 ret = krb5_auth_con_init(context, &auth_context);
339 DEBUG(1,("ads_verify_ticket: krb5_auth_con_init failed (%s)\n", error_message(ret)));
343 asprintf(&host_princ_s, "%s$", global_myname());
344 strlower_m(host_princ_s);
345 ret = smb_krb5_parse_name(context, host_princ_s, &host_princ);
347 DEBUG(1,("ads_verify_ticket: smb_krb5_parse_name(%s) failed (%s)\n",
348 host_princ_s, error_message(ret)));
353 /* Lock a mutex surrounding the replay as there is no locking in the MIT krb5
354 * code surrounding the replay cache... */
356 if (!grab_server_mutex("replay cache mutex")) {
357 DEBUG(1,("ads_verify_ticket: unable to protect replay cache with mutex.\n"));
361 got_replay_mutex = True;
364 * JRA. We must set the rcache here. This will prevent replay attacks.
367 ret = krb5_get_server_rcache(context, krb5_princ_component(context, host_princ, 0), &rcache);
369 DEBUG(1,("ads_verify_ticket: krb5_get_server_rcache failed (%s)\n", error_message(ret)));
373 ret = krb5_auth_con_setrcache(context, auth_context, rcache);
375 DEBUG(1,("ads_verify_ticket: krb5_auth_con_setrcache failed (%s)\n", error_message(ret)));
379 if (lp_use_kerberos_keytab()) {
380 auth_ok = ads_keytab_verify_ticket(context, auth_context, ticket, &packet, &tkt, &keyblock);
383 auth_ok = ads_secrets_verify_ticket(context, auth_context, host_princ,
384 ticket, &packet, &tkt, &keyblock);
387 release_server_mutex();
388 got_replay_mutex = False;
391 /* Heimdal leaks here, if we fix the leak, MIT crashes */
393 krb5_rc_close(context, rcache);
398 DEBUG(3,("ads_verify_ticket: krb5_rd_req with auth failed (%s)\n",
399 error_message(ret)));
403 authtime = get_authtime_from_tkt(tkt);
404 client_principal = get_principal_from_tkt(tkt);
406 ret = krb5_mk_rep(context, auth_context, &packet);
408 DEBUG(3,("ads_verify_ticket: Failed to generate mutual authentication reply (%s)\n",
409 error_message(ret)));
413 *ap_rep = data_blob(packet.data, packet.length);
414 SAFE_FREE(packet.data);
417 get_krb5_smb_session_key(context, auth_context, session_key, True);
418 dump_data_pw("SMB session key (from ticket)\n", session_key->data, session_key->length);
421 file_save("/tmp/ticket.dat", ticket->data, ticket->length);
424 /* continue when no PAC is retrieved or we couldn't decode the PAC
425 (like accounts that have the UF_NO_AUTH_DATA_REQUIRED flag set, or
426 Kerberos tickets encrypted using a DES key) - Guenther */
428 got_auth_data = get_auth_data_from_tkt(mem_ctx, &auth_data, tkt);
429 if (!got_auth_data) {
430 DEBUG(3,("ads_verify_ticket: did not retrieve auth data. continuing without PAC\n"));
433 if (got_auth_data && pac_data != NULL) {
435 pac_ret = decode_pac_data(mem_ctx, &auth_data, context, keyblock, client_principal, authtime, pac_data);
436 if (!NT_STATUS_IS_OK(pac_ret)) {
437 DEBUG(3,("ads_verify_ticket: failed to decode PAC_DATA: %s\n", nt_errstr(pac_ret)));
440 data_blob_free(&auth_data);
444 #if defined(HAVE_KRB5_TKT_ENC_PART2)
446 if (tkt->enc_part2) {
447 file_save("/tmp/authdata.dat",
448 tkt->enc_part2->authorization_data[0]->contents,
449 tkt->enc_part2->authorization_data[0]->length);
453 if (tkt->ticket.authorization_data) {
454 file_save("/tmp/authdata.dat",
455 tkt->ticket.authorization_data->val->ad_data.data,
456 tkt->ticket.authorization_data->val->ad_data.length);
461 if ((ret = smb_krb5_unparse_name(context, client_principal, principal))) {
462 DEBUG(3,("ads_verify_ticket: smb_krb5_unparse_name failed (%s)\n",
463 error_message(ret)));
464 sret = NT_STATUS_LOGON_FAILURE;
472 if (got_replay_mutex) {
473 release_server_mutex();
476 if (!NT_STATUS_IS_OK(sret)) {
477 data_blob_free(&auth_data);
480 if (!NT_STATUS_IS_OK(sret)) {
481 data_blob_free(ap_rep);
485 krb5_free_principal(context, host_princ);
489 krb5_free_keyblock(context, keyblock);
493 krb5_free_ticket(context, tkt);
496 SAFE_FREE(host_princ_s);
499 krb5_auth_con_free(context, auth_context);
503 krb5_free_context(context);
509 #endif /* HAVE_KRB5 */