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);
138 * Return a freshly allocated ccache (destroyed by destructor on child
139 * of parent_ctx), for a given set of client credentials
142 krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
143 struct cli_credentials *credentials,
144 struct smb_krb5_context *smb_krb5_context,
145 struct tevent_context *event_ctx,
147 enum credentials_obtained *obtained,
148 const char **error_string)
151 const char *password;
152 const char *self_service;
153 const char *target_service;
155 krb5_principal princ;
156 krb5_principal impersonate_principal;
158 TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
159 krb5_get_init_creds_opt *krb_options;
162 (*error_string) = strerror(ENOMEM);
166 ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
168 talloc_free(mem_ctx);
173 (*error_string) = talloc_asprintf(credentials, "principal, username or realm was not specified in the credentials");
174 talloc_free(mem_ctx);
175 return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
178 ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
180 talloc_free(mem_ctx);
184 self_service = cli_credentials_get_self_service(credentials);
185 target_service = cli_credentials_get_target_service(credentials);
187 password = cli_credentials_get_password(credentials);
189 /* setup the krb5 options we want */
190 if ((ret = krb5_get_init_creds_opt_alloc(smb_krb5_context->krb5_context, &krb_options))) {
191 (*error_string) = talloc_asprintf(credentials, "krb5_get_init_creds_opt_alloc failed (%s)\n",
192 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
194 talloc_free(mem_ctx);
198 /* get the defaults */
199 krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
201 /* set if we want a forwardable ticket */
202 switch (cli_credentials_get_krb_forwardable(credentials)) {
203 case CRED_AUTO_KRB_FORWARDABLE:
205 case CRED_NO_KRB_FORWARDABLE:
206 krb5_get_init_creds_opt_set_forwardable(krb_options, FALSE);
208 case CRED_FORCE_KRB_FORWARDABLE:
209 krb5_get_init_creds_opt_set_forwardable(krb_options, TRUE);
214 * In order to work against windows KDCs even if we use
215 * the netbios domain name as realm, we need to add the following
217 * KRB5_INIT_CREDS_NO_C_CANON_CHECK;
218 * KRB5_INIT_CREDS_NO_C_NO_EKU_CHECK;
220 krb5_get_init_creds_opt_set_win2k(smb_krb5_context->krb5_context,
225 struct tevent_context *previous_ev;
226 /* Do this every time, in case we have weird recursive issues here */
227 ret = smb_krb5_context_set_event_ctx(smb_krb5_context, event_ctx, &previous_ev);
229 talloc_free(mem_ctx);
233 ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
235 impersonate_principal,
240 } else if (impersonate_principal) {
241 talloc_free(mem_ctx);
242 (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock. A password must be specified in the credentials";
245 /* No password available, try to use a keyblock instead */
247 krb5_keyblock keyblock;
248 const struct samr_Password *mach_pwd;
249 mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
251 talloc_free(mem_ctx);
252 (*error_string) = "kinit_to_ccache: No password available for kinit\n";
253 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
254 smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
257 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
258 ENCTYPE_ARCFOUR_HMAC,
259 mach_pwd->hash, sizeof(mach_pwd->hash),
263 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
265 target_service, krb_options,
267 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
271 smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
273 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
274 /* Perhaps we have been given an invalid skew, so try again without it */
275 time_t t = time(NULL);
276 krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
278 /* not a skew problem */
283 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
285 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
286 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
287 cli_credentials_get_principal(credentials, mem_ctx),
288 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
290 talloc_free(mem_ctx);
294 /* cope with ticket being in the future due to clock skew */
295 if ((unsigned)kdc_time > time(NULL)) {
296 time_t t = time(NULL);
297 int time_offset =(unsigned)kdc_time-t;
298 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
299 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
302 if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
303 ret = kinit_to_ccache(parent_ctx,
312 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
313 cli_credentials_get_principal(credentials, mem_ctx),
314 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
316 talloc_free(mem_ctx);
319 talloc_free(mem_ctx);
323 static krb5_error_code free_keytab_container(struct keytab_container *ktc)
325 return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
328 krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
329 struct smb_krb5_context *smb_krb5_context,
330 krb5_keytab opt_keytab,
331 const char *keytab_name,
332 struct keytab_container **ktc)
340 ret = krb5_kt_resolve(smb_krb5_context->krb5_context,
341 keytab_name, &keytab);
343 DEBUG(1,("failed to open krb5 keytab: %s\n",
344 smb_get_krb5_error_message(
345 smb_krb5_context->krb5_context,
351 *ktc = talloc(mem_ctx, struct keytab_container);
356 (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
357 (*ktc)->keytab = keytab;
358 talloc_set_destructor(*ktc, free_keytab_container);