2 * GSSAPI Security Extensions
4 * Copyright (C) Simo Sorce 2010.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
23 #include "librpc/rpc/dcerpc_krb5.h"
27 static krb5_error_code flush_keytab(krb5_context krbctx, krb5_keytab keytab)
30 krb5_kt_cursor kt_cursor;
31 krb5_keytab_entry kt_entry;
33 ZERO_STRUCT(kt_entry);
35 ret = krb5_kt_start_seq_get(krbctx, keytab, &kt_cursor);
36 if (ret == KRB5_KT_END || ret == ENOENT ) {
41 ret = krb5_kt_next_entry(krbctx, keytab, &kt_entry, &kt_cursor);
44 /* we need to close and reopen enumeration because we modify
46 ret = krb5_kt_end_seq_get(krbctx, keytab, &kt_cursor);
48 DEBUG(1, (__location__ ": krb5_kt_end_seq_get() "
49 "failed (%s)\n", error_message(ret)));
53 /* remove the entry */
54 ret = krb5_kt_remove_entry(krbctx, keytab, &kt_entry);
56 DEBUG(1, (__location__ ": krb5_kt_remove_entry() "
57 "failed (%s)\n", error_message(ret)));
60 ret = smb_krb5_kt_free_entry(krbctx, &kt_entry);
61 ZERO_STRUCT(kt_entry);
64 ret = krb5_kt_start_seq_get(krbctx, keytab, &kt_cursor);
66 DEBUG(1, (__location__ ": krb5_kt_start_seq() failed "
67 "(%s)\n", error_message(ret)));
71 ret = krb5_kt_next_entry(krbctx, keytab,
72 &kt_entry, &kt_cursor);
75 if (ret != KRB5_KT_END && ret != ENOENT) {
76 DEBUG(1, (__location__ ": flushing keytab we got [%s]!\n",
86 static krb5_error_code get_host_principal(krb5_context krbctx,
87 krb5_principal *host_princ)
90 char *host_princ_s = NULL;
93 err = asprintf(&host_princ_s, "%s$@%s", global_myname(), lp_realm());
98 strlower_m(host_princ_s);
99 ret = smb_krb5_parse_name(krbctx, host_princ_s, host_princ);
101 DEBUG(1, (__location__ ": smb_krb5_parse_name(%s) "
103 host_princ_s, error_message(ret)));
106 SAFE_FREE(host_princ_s);
110 static krb5_error_code fill_keytab_from_password(krb5_context krbctx,
112 krb5_principal princ,
117 krb5_enctype *enctypes;
118 krb5_keytab_entry kt_entry;
121 ret = get_kerberos_allowed_etypes(krbctx, &enctypes);
123 DEBUG(1, (__location__
124 ": Can't determine permitted enctypes!\n"));
128 for (i = 0; enctypes[i]; i++) {
129 krb5_keyblock *key = NULL;
131 if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
136 if (create_kerberos_key_from_string(krbctx, princ,
138 enctypes[i], false)) {
139 DEBUG(10, ("Failed to create key for enctype %d "
141 enctypes[i], error_message(ret)));
146 kt_entry.principal = princ;
150 ret = krb5_kt_add_entry(krbctx, keytab, &kt_entry);
152 DEBUG(1, (__location__ ": Failed to add entry to "
153 "keytab for enctype %d (error: %s)\n",
154 enctypes[i], error_message(ret)));
155 krb5_free_keyblock(krbctx, key);
159 krb5_free_keyblock(krbctx, key);
169 #define SRV_MEM_KEYTAB_NAME "MEMORY:cifs_srv_keytab"
170 #define CLEARTEXT_PRIV_ENCTYPE -99
172 static krb5_error_code get_mem_keytab_from_secrets(krb5_context krbctx,
178 krb5_kt_cursor kt_cursor;
179 krb5_keytab_entry kt_entry;
181 krb5_principal princ = NULL;
182 krb5_kvno kvno = 0; /* FIXME: fetch current vno from KDC ? */
183 char *pwd_old = NULL;
185 if (!secrets_init()) {
186 DEBUG(1, (__location__ ": secrets_init failed\n"));
187 return KRB5_CONFIG_CANTOPEN;
190 pwd = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
192 DEBUG(2, (__location__ ": failed to fetch machine password\n"));
193 return KRB5_LIBOS_CANTREADPWD;
195 pwd_len = strlen(pwd);
197 if (*keytab == NULL) {
198 /* create memory keytab */
199 ret = krb5_kt_resolve(krbctx, SRV_MEM_KEYTAB_NAME, keytab);
201 DEBUG(1, (__location__ ": Failed to get memory "
207 ZERO_STRUCT(kt_entry);
208 ZERO_STRUCT(kt_cursor);
210 /* check if the keytab already has any entry */
211 ret = krb5_kt_start_seq_get(krbctx, *keytab, &kt_cursor);
212 if (ret != KRB5_KT_END && ret != ENOENT ) {
213 /* check if we have our special enctype used to hold
214 * the clear text password. If so, check it out so that
215 * we can verify if the keytab needs to be upgraded */
216 while ((ret = krb5_kt_next_entry(krbctx, *keytab,
217 &kt_entry, &kt_cursor)) == 0) {
218 if (smb_get_enctype_from_kt_entry(&kt_entry) == CLEARTEXT_PRIV_ENCTYPE) {
221 smb_krb5_kt_free_entry(krbctx, &kt_entry);
222 ZERO_STRUCT(kt_entry);
225 if (ret != 0 && ret != KRB5_KT_END && ret != ENOENT ) {
226 /* Error parsing keytab */
227 DEBUG(1, (__location__ ": Failed to parse memory "
233 /* found private entry,
234 * check if keytab is up to date */
236 if ((pwd_len == KRB5_KEY_LENGTH(KRB5_KT_KEY(&kt_entry))) &&
237 (memcmp(KRB5_KEY_DATA(KRB5_KT_KEY(&kt_entry)),
238 pwd, pwd_len) == 0)) {
239 /* keytab is already up to date, return */
240 smb_krb5_kt_free_entry(krbctx, &kt_entry);
244 smb_krb5_kt_free_entry(krbctx, &kt_entry);
245 ZERO_STRUCT(kt_entry);
248 /* flush keytab, we need to regen it */
249 ret = flush_keytab(krbctx, *keytab);
251 DEBUG(1, (__location__ ": Failed to flush "
252 "memory keytab!\n"));
259 krb5_kt_cursor zero_csr;
260 ZERO_STRUCT(zero_csr);
261 if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && *keytab) {
262 krb5_kt_end_seq_get(krbctx, *keytab, &kt_cursor);
266 /* keytab is not up to date, fill it up */
268 ret = get_host_principal(krbctx, &princ);
270 DEBUG(1, (__location__ ": Failed to get host principal!\n"));
275 password.length = pwd_len;
276 ret = fill_keytab_from_password(krbctx, *keytab,
277 princ, kvno, &password);
279 DEBUG(1, (__location__ ": Failed to fill memory keytab!\n"));
283 pwd_old = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
285 DEBUG(10, (__location__ ": no prev machine password\n"));
287 password.data = pwd_old;
288 password.length = strlen(pwd_old);
289 ret = fill_keytab_from_password(krbctx, *keytab,
290 princ, kvno -1, &password);
292 DEBUG(1, (__location__
293 ": Failed to fill memory keytab!\n"));
298 /* add our private enctype + cleartext password so that we can
299 * update the keytab if secrets change later on */
300 ZERO_STRUCT(kt_entry);
301 kt_entry.principal = princ;
304 KRB5_KEY_TYPE(KRB5_KT_KEY(&kt_entry)) = CLEARTEXT_PRIV_ENCTYPE;
305 KRB5_KEY_LENGTH(KRB5_KT_KEY(&kt_entry)) = pwd_len;
306 KRB5_KEY_DATA(KRB5_KT_KEY(&kt_entry)) = (uint8_t *)pwd;
308 ret = krb5_kt_add_entry(krbctx, *keytab, &kt_entry);
310 DEBUG(1, (__location__ ": Failed to add entry to "
311 "keytab for private enctype (%d) (error: %s)\n",
312 CLEARTEXT_PRIV_ENCTYPE, error_message(ret)));
323 krb5_kt_cursor zero_csr;
324 ZERO_STRUCT(zero_csr);
325 if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && *keytab) {
326 krb5_kt_end_seq_get(krbctx, *keytab, &kt_cursor);
331 krb5_free_principal(krbctx, princ);
336 krb5_kt_close(krbctx, *keytab);
344 static krb5_error_code get_mem_keytab_from_system_keytab(krb5_context krbctx,
348 return KRB5_KT_NOTFOUND;
351 krb5_error_code smb_krb5_get_server_keytab(krb5_context krbctx,
358 switch (lp_kerberos_method()) {
360 case KERBEROS_VERIFY_SECRETS:
361 ret = get_mem_keytab_from_secrets(krbctx, keytab);
363 case KERBEROS_VERIFY_SYSTEM_KEYTAB:
364 ret = get_mem_keytab_from_system_keytab(krbctx, keytab, true);
366 case KERBEROS_VERIFY_DEDICATED_KEYTAB:
367 /* just use whatever keytab is configured */
368 ret = get_mem_keytab_from_system_keytab(krbctx, keytab, false);
370 case KERBEROS_VERIFY_SECRETS_AND_KEYTAB:
371 ret = get_mem_keytab_from_secrets(krbctx, keytab);
373 DEBUG(3, (__location__ ": Warning! Unable to set mem "
374 "keytab from secrets!\n"));
376 /* Now append system keytab keys too */
377 ret = get_mem_keytab_from_system_keytab(krbctx, keytab, true);
379 DEBUG(3, (__location__ ": Warning! Unable to set mem "
380 "keytab from secrets!\n"));
388 #endif /* HAVE_KRB5 */