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 #ifdef SAMBA4_USES_HEIMDAL /* Disable for now MIT reads defaults when needed */
199 /* get the defaults */
200 krb5_get_init_creds_opt_set_default_flags(smb_krb5_context
->krb5_context
, NULL
, NULL
, krb_options
);
202 /* set if we want a forwardable ticket */
203 switch (cli_credentials_get_krb_forwardable(credentials
)) {
204 case CRED_AUTO_KRB_FORWARDABLE
:
206 case CRED_NO_KRB_FORWARDABLE
:
207 krb5_get_init_creds_opt_set_forwardable(krb_options
, FALSE
);
209 case CRED_FORCE_KRB_FORWARDABLE
:
210 krb5_get_init_creds_opt_set_forwardable(krb_options
, TRUE
);
214 #ifdef SAMBA4_USES_HEIMDAL /* FIXME: MIT does not have this yet */
216 * In order to work against windows KDCs even if we use
217 * the netbios domain name as realm, we need to add the following
219 * KRB5_INIT_CREDS_NO_C_CANON_CHECK;
220 * KRB5_INIT_CREDS_NO_C_NO_EKU_CHECK;
222 krb5_get_init_creds_opt_set_win2k(smb_krb5_context
->krb5_context
,
228 #ifdef SAMBA4_USES_HEIMDAL
229 struct tevent_context
*previous_ev
;
230 /* Do this every time, in case we have weird recursive issues here */
231 ret
= smb_krb5_context_set_event_ctx(smb_krb5_context
, event_ctx
, &previous_ev
);
233 talloc_free(mem_ctx
);
238 if (impersonate_principal
) {
239 #ifdef SAMBA4_USES_HEIMDAL
240 ret
= kerberos_kinit_s4u2_cc(
241 smb_krb5_context
->krb5_context
,
242 ccache
, princ
, password
,
243 impersonate_principal
,
244 self_service
, target_service
,
245 krb_options
, NULL
, &kdc_time
);
247 talloc_free(mem_ctx
);
248 (*error_string
) = "INTERNAL error: s4u2 ops "
249 "are not supported with MIT build yet";
253 ret
= kerberos_kinit_password_cc(
254 smb_krb5_context
->krb5_context
,
255 ccache
, princ
, password
,
257 krb_options
, NULL
, &kdc_time
);
259 } else if (impersonate_principal
) {
260 talloc_free(mem_ctx
);
261 (*error_string
) = "INTERNAL error: Cannot impersonate principal with just a keyblock. A password must be specified in the credentials";
264 /* No password available, try to use a keyblock instead */
266 krb5_keyblock keyblock
;
267 const struct samr_Password
*mach_pwd
;
268 mach_pwd
= cli_credentials_get_nt_hash(credentials
, mem_ctx
);
270 talloc_free(mem_ctx
);
271 (*error_string
) = "kinit_to_ccache: No password available for kinit\n";
272 krb5_get_init_creds_opt_free(smb_krb5_context
->krb5_context
, krb_options
);
273 #ifdef SAMBA4_USES_HEIMDAL
274 smb_krb5_context_remove_event_ctx(smb_krb5_context
, previous_ev
, event_ctx
);
278 ret
= smb_krb5_keyblock_init_contents(smb_krb5_context
->krb5_context
,
279 ENCTYPE_ARCFOUR_HMAC
,
280 mach_pwd
->hash
, sizeof(mach_pwd
->hash
),
284 ret
= kerberos_kinit_keyblock_cc(smb_krb5_context
->krb5_context
, ccache
,
286 target_service
, krb_options
,
288 krb5_free_keyblock_contents(smb_krb5_context
->krb5_context
, &keyblock
);
292 #ifdef SAMBA4_USES_HEIMDAL
293 smb_krb5_context_remove_event_ctx(smb_krb5_context
, previous_ev
, event_ctx
);
296 if (ret
== KRB5KRB_AP_ERR_SKEW
|| ret
== KRB5_KDCREP_SKEW
) {
297 /* Perhaps we have been given an invalid skew, so try again without it */
298 time_t t
= time(NULL
);
299 krb5_set_real_time(smb_krb5_context
->krb5_context
, t
, 0);
301 /* not a skew problem */
306 krb5_get_init_creds_opt_free(smb_krb5_context
->krb5_context
, krb_options
);
308 if (ret
== KRB5KRB_AP_ERR_SKEW
|| ret
== KRB5_KDCREP_SKEW
) {
309 (*error_string
) = talloc_asprintf(credentials
, "kinit for %s failed (%s)\n",
310 cli_credentials_get_principal(credentials
, mem_ctx
),
311 smb_get_krb5_error_message(smb_krb5_context
->krb5_context
,
313 talloc_free(mem_ctx
);
317 /* cope with ticket being in the future due to clock skew */
318 if ((unsigned)kdc_time
> time(NULL
)) {
319 time_t t
= time(NULL
);
320 int time_offset
=(unsigned)kdc_time
-t
;
321 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset
));
322 krb5_set_real_time(smb_krb5_context
->krb5_context
, t
+ time_offset
+ 1, 0);
325 if (ret
== KRB5KDC_ERR_PREAUTH_FAILED
&& cli_credentials_wrong_password(credentials
)) {
326 ret
= kinit_to_ccache(parent_ctx
,
335 (*error_string
) = talloc_asprintf(credentials
, "kinit for %s failed (%s)\n",
336 cli_credentials_get_principal(credentials
, mem_ctx
),
337 smb_get_krb5_error_message(smb_krb5_context
->krb5_context
,
339 talloc_free(mem_ctx
);
342 talloc_free(mem_ctx
);
346 static krb5_error_code
free_keytab_container(struct keytab_container
*ktc
)
348 return krb5_kt_close(ktc
->smb_krb5_context
->krb5_context
, ktc
->keytab
);
351 krb5_error_code
smb_krb5_get_keytab_container(TALLOC_CTX
*mem_ctx
,
352 struct smb_krb5_context
*smb_krb5_context
,
353 krb5_keytab opt_keytab
,
354 const char *keytab_name
,
355 struct keytab_container
**ktc
)
363 ret
= krb5_kt_resolve(smb_krb5_context
->krb5_context
,
364 keytab_name
, &keytab
);
366 DEBUG(1,("failed to open krb5 keytab: %s\n",
367 smb_get_krb5_error_message(
368 smb_krb5_context
->krb5_context
,
374 *ktc
= talloc(mem_ctx
, struct keytab_container
);
379 (*ktc
)->smb_krb5_context
= talloc_reference(*ktc
, smb_krb5_context
);
380 (*ktc
)->keytab
= keytab
;
381 (*ktc
)->password_based
= false;
382 talloc_set_destructor(*ktc
, free_keytab_container
);