s3-auth: Use the gensec-supplied DNS domain name and hostname.
[nivanova/samba-autobuild/.git] / auth / kerberos / kerberos_pac.c
1 /*
2    Unix SMB/CIFS implementation.
3    kerberos authorization data (PAC) utility library
4    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
6    Copyright (C) Andrew Tridgell 2001
7    Copyright (C) Luke Howard 2002-2003
8    Copyright (C) Stefan Metzmacher 2004-2005
9    Copyright (C) Guenther Deschner 2005,2007,2008
10
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 3 of the License, or
14    (at your option) any later version.
15
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.
20
21    You should have received a copy of the GNU General Public License
22    along with this program.  If not, see <http://www.gnu.org/licenses/>.
23 */
24
25 #include "includes.h"
26 #ifdef HAVE_KRB5
27
28 #include "librpc/gen_ndr/ndr_krb5pac.h"
29 #include "libcli/auth/krb5_wrap.h"
30
31 krb5_error_code check_pac_checksum(DATA_BLOB pac_data,
32                                           struct PAC_SIGNATURE_DATA *sig,
33                                           krb5_context context,
34                                           const krb5_keyblock *keyblock)
35 {
36         krb5_error_code ret;
37         krb5_checksum cksum;
38         krb5_keyusage usage = 0;
39
40         smb_krb5_checksum_from_pac_sig(&cksum, sig);
41
42 #ifdef HAVE_KRB5_KU_OTHER_CKSUM /* Heimdal */
43         usage = KRB5_KU_OTHER_CKSUM;
44 #elif defined(HAVE_KRB5_KEYUSAGE_APP_DATA_CKSUM) /* MIT */
45         usage = KRB5_KEYUSAGE_APP_DATA_CKSUM;
46 #else
47 #error UNKNOWN_KRB5_KEYUSAGE
48 #endif
49
50         ret = smb_krb5_verify_checksum(context,
51                                        keyblock,
52                                        usage,
53                                        &cksum,
54                                        pac_data.data,
55                                        pac_data.length);
56
57         if (ret) {
58                 DEBUG(2,("check_pac_checksum: PAC Verification failed: %s (%d)\n",
59                         error_message(ret), ret));
60                 return ret;
61         }
62
63         return ret;
64 }
65
66 /**
67 * @brief Decode a blob containing a NDR envoded PAC structure
68 *
69 * @param mem_ctx          - The memory context
70 * @param pac_data_blob    - The data blob containing the NDR encoded data
71 * @param context          - The Kerberos Context
72 * @param service_keyblock - The Service Key used to verify the checksum
73 * @param client_principal - The client principal
74 * @param tgs_authtime     - The ticket timestamp
75 * @param pac_data_out     - [out] The decoded PAC
76 *
77 * @return - A NTSTATUS error code
78 */
79 NTSTATUS kerberos_decode_pac(TALLOC_CTX *mem_ctx,
80                              DATA_BLOB pac_data_blob,
81                              krb5_context context,
82                              const krb5_keyblock *krbtgt_keyblock,
83                              const krb5_keyblock *service_keyblock,
84                              krb5_const_principal client_principal,
85                              time_t tgs_authtime,
86                              struct PAC_DATA **pac_data_out)
87 {
88         NTSTATUS status;
89         enum ndr_err_code ndr_err;
90         krb5_error_code ret;
91         DATA_BLOB modified_pac_blob;
92
93         NTTIME tgs_authtime_nttime;
94         krb5_principal client_principal_pac = NULL;
95         int i;
96
97         struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
98         struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
99         struct PAC_SIGNATURE_DATA *srv_sig_wipe = NULL;
100         struct PAC_SIGNATURE_DATA *kdc_sig_wipe = NULL;
101         struct PAC_LOGON_NAME *logon_name = NULL;
102         struct PAC_LOGON_INFO *logon_info = NULL;
103         struct PAC_DATA *pac_data = NULL;
104         struct PAC_DATA_RAW *pac_data_raw = NULL;
105
106         DATA_BLOB *srv_sig_blob = NULL;
107         DATA_BLOB *kdc_sig_blob = NULL;
108
109         bool bool_ret;
110
111         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
112         if (!tmp_ctx) {
113                 return NT_STATUS_NO_MEMORY;
114         }
115
116         if (pac_data_out) {
117                 *pac_data_out = NULL;
118         }
119
120         pac_data = talloc(tmp_ctx, struct PAC_DATA);
121         pac_data_raw = talloc(tmp_ctx, struct PAC_DATA_RAW);
122         kdc_sig_wipe = talloc(tmp_ctx, struct PAC_SIGNATURE_DATA);
123         srv_sig_wipe = talloc(tmp_ctx, struct PAC_SIGNATURE_DATA);
124         if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
125                 talloc_free(tmp_ctx);
126                 return NT_STATUS_NO_MEMORY;
127         }
128
129         ndr_err = ndr_pull_struct_blob(&pac_data_blob, pac_data, pac_data,
130                        (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
131         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
132                 status = ndr_map_error2ntstatus(ndr_err);
133                 DEBUG(0,("can't parse the PAC: %s\n",
134                         nt_errstr(status)));
135                 talloc_free(tmp_ctx);
136                 return status;
137         }
138
139         if (pac_data->num_buffers < 4) {
140                 /* we need logon_ingo, service_key and kdc_key */
141                 DEBUG(0,("less than 4 PAC buffers\n"));
142                 talloc_free(tmp_ctx);
143                 return NT_STATUS_INVALID_PARAMETER;
144         }
145
146         ndr_err = ndr_pull_struct_blob(
147                                 &pac_data_blob, pac_data_raw, pac_data_raw,
148                                 (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA_RAW);
149         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
150                 status = ndr_map_error2ntstatus(ndr_err);
151                 DEBUG(0,("can't parse the PAC: %s\n",
152                         nt_errstr(status)));
153                 talloc_free(tmp_ctx);
154                 return status;
155         }
156
157         if (pac_data_raw->num_buffers < 4) {
158                 /* we need logon_ingo, service_key and kdc_key */
159                 DEBUG(0,("less than 4 PAC buffers\n"));
160                 talloc_free(tmp_ctx);
161                 return NT_STATUS_INVALID_PARAMETER;
162         }
163
164         if (pac_data->num_buffers != pac_data_raw->num_buffers) {
165                 /* we need logon_ingo, service_key and kdc_key */
166                 DEBUG(0, ("misparse! PAC_DATA has %d buffers while "
167                           "PAC_DATA_RAW has %d\n", pac_data->num_buffers,
168                           pac_data_raw->num_buffers));
169                 talloc_free(tmp_ctx);
170                 return NT_STATUS_INVALID_PARAMETER;
171         }
172
173         for (i=0; i < pac_data->num_buffers; i++) {
174                 struct PAC_BUFFER *data_buf = &pac_data->buffers[i];
175                 struct PAC_BUFFER_RAW *raw_buf = &pac_data_raw->buffers[i];
176
177                 if (data_buf->type != raw_buf->type) {
178                         DEBUG(0, ("misparse! PAC_DATA buffer %d has type "
179                                   "%d while PAC_DATA_RAW has %d\n", i,
180                                   data_buf->type, raw_buf->type));
181                         talloc_free(tmp_ctx);
182                         return NT_STATUS_INVALID_PARAMETER;
183                 }
184                 switch (data_buf->type) {
185                 case PAC_TYPE_LOGON_INFO:
186                         if (!data_buf->info) {
187                                 break;
188                         }
189                         logon_info = data_buf->info->logon_info.info;
190                         break;
191                 case PAC_TYPE_SRV_CHECKSUM:
192                         if (!data_buf->info) {
193                                 break;
194                         }
195                         srv_sig_ptr = &data_buf->info->srv_cksum;
196                         srv_sig_blob = &raw_buf->info->remaining;
197                         break;
198                 case PAC_TYPE_KDC_CHECKSUM:
199                         if (!data_buf->info) {
200                                 break;
201                         }
202                         kdc_sig_ptr = &data_buf->info->kdc_cksum;
203                         kdc_sig_blob = &raw_buf->info->remaining;
204                         break;
205                 case PAC_TYPE_LOGON_NAME:
206                         logon_name = &data_buf->info->logon_name;
207                         break;
208                 default:
209                         break;
210                 }
211         }
212
213         if (!logon_info) {
214                 DEBUG(0,("PAC no logon_info\n"));
215                 talloc_free(tmp_ctx);
216                 return NT_STATUS_INVALID_PARAMETER;
217         }
218
219         if (!logon_name) {
220                 DEBUG(0,("PAC no logon_name\n"));
221                 talloc_free(tmp_ctx);
222                 return NT_STATUS_INVALID_PARAMETER;
223         }
224
225         if (!srv_sig_ptr || !srv_sig_blob) {
226                 DEBUG(0,("PAC no srv_key\n"));
227                 talloc_free(tmp_ctx);
228                 return NT_STATUS_INVALID_PARAMETER;
229         }
230
231         if (!kdc_sig_ptr || !kdc_sig_blob) {
232                 DEBUG(0,("PAC no kdc_key\n"));
233                 talloc_free(tmp_ctx);
234                 return NT_STATUS_INVALID_PARAMETER;
235         }
236
237         /* Find and zero out the signatures,
238          * as required by the signing algorithm */
239
240         /* We find the data blobs above,
241          * now we parse them to get at the exact portion we should zero */
242         ndr_err = ndr_pull_struct_blob(
243                         kdc_sig_blob, kdc_sig_wipe, kdc_sig_wipe,
244                         (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
245         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
246                 status = ndr_map_error2ntstatus(ndr_err);
247                 DEBUG(0,("can't parse the KDC signature: %s\n",
248                         nt_errstr(status)));
249                 talloc_free(tmp_ctx);
250                 return status;
251         }
252
253         ndr_err = ndr_pull_struct_blob(
254                         srv_sig_blob, srv_sig_wipe, srv_sig_wipe,
255                         (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
256         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
257                 status = ndr_map_error2ntstatus(ndr_err);
258                 DEBUG(0,("can't parse the SRV signature: %s\n",
259                         nt_errstr(status)));
260                 talloc_free(tmp_ctx);
261                 return status;
262         }
263
264         /* Now zero the decoded structure */
265         memset(kdc_sig_wipe->signature.data,
266                 '\0', kdc_sig_wipe->signature.length);
267         memset(srv_sig_wipe->signature.data,
268                 '\0', srv_sig_wipe->signature.length);
269
270         /* and reencode, back into the same place it came from */
271         ndr_err = ndr_push_struct_blob(
272                         kdc_sig_blob, pac_data_raw, kdc_sig_wipe,
273                         (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
274         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
275                 status = ndr_map_error2ntstatus(ndr_err);
276                 DEBUG(0,("can't repack the KDC signature: %s\n",
277                         nt_errstr(status)));
278                 talloc_free(tmp_ctx);
279                 return status;
280         }
281         ndr_err = ndr_push_struct_blob(
282                         srv_sig_blob, pac_data_raw, srv_sig_wipe,
283                         (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
284         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
285                 status = ndr_map_error2ntstatus(ndr_err);
286                 DEBUG(0,("can't repack the SRV signature: %s\n",
287                         nt_errstr(status)));
288                 talloc_free(tmp_ctx);
289                 return status;
290         }
291
292         /* push out the whole structure, but now with zero'ed signatures */
293         ndr_err = ndr_push_struct_blob(
294                         &modified_pac_blob, pac_data_raw, pac_data_raw,
295                         (ndr_push_flags_fn_t)ndr_push_PAC_DATA_RAW);
296         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
297                 status = ndr_map_error2ntstatus(ndr_err);
298                 DEBUG(0,("can't repack the RAW PAC: %s\n",
299                         nt_errstr(status)));
300                 talloc_free(tmp_ctx);
301                 return status;
302         }
303
304         if (service_keyblock) {
305                 /* verify by service_key */
306                 ret = check_pac_checksum(modified_pac_blob, srv_sig_ptr,
307                                          context,
308                                          service_keyblock);
309                 if (ret) {
310                         DEBUG(1, ("PAC Decode: Failed to verify the service "
311                                   "signature: %s\n", error_message(ret)));
312                         return NT_STATUS_ACCESS_DENIED;
313                 }
314
315                 if (krbtgt_keyblock) {
316                         /* verify the service key checksum by krbtgt_key */
317                         ret = check_pac_checksum(srv_sig_ptr->signature, kdc_sig_ptr,
318                                                  context, krbtgt_keyblock);
319                         if (ret) {
320                                 DEBUG(1, ("PAC Decode: Failed to verify the KDC signature: %s\n",
321                                           smb_get_krb5_error_message(context, ret, tmp_ctx)));
322                                 talloc_free(tmp_ctx);
323                                 return NT_STATUS_ACCESS_DENIED;
324                         }
325                 }
326         }
327
328         if (tgs_authtime) {
329                 /* Convert to NT time, so as not to loose accuracy in comparison */
330                 unix_to_nt_time(&tgs_authtime_nttime, tgs_authtime);
331
332                 if (tgs_authtime_nttime != logon_name->logon_time) {
333                         DEBUG(2, ("PAC Decode: "
334                                   "Logon time mismatch between ticket and PAC!\n"));
335                         DEBUG(2, ("PAC Decode: PAC: %s\n",
336                                   nt_time_string(tmp_ctx, logon_name->logon_time)));
337                         DEBUG(2, ("PAC Decode: Ticket: %s\n",
338                                   nt_time_string(tmp_ctx, tgs_authtime_nttime)));
339                         talloc_free(tmp_ctx);
340                         return NT_STATUS_ACCESS_DENIED;
341                 }
342         }
343
344         if (client_principal) {
345                 ret = smb_krb5_parse_name_norealm(context,
346                                                   logon_name->account_name,
347                                                   &client_principal_pac);
348                 if (ret) {
349                         DEBUG(2, ("Could not parse name from PAC: [%s]:%s\n",
350                                   logon_name->account_name, error_message(ret)));
351                         talloc_free(tmp_ctx);
352                         return NT_STATUS_INVALID_PARAMETER;
353                 }
354
355                 bool_ret = smb_krb5_principal_compare_any_realm(context,
356                                                                 client_principal,
357                                                                 client_principal_pac);
358
359                 krb5_free_principal(context, client_principal_pac);
360
361                 if (!bool_ret) {
362                         DEBUG(2, ("Name in PAC [%s] does not match principal name "
363                                   "in ticket\n", logon_name->account_name));
364                         talloc_free(tmp_ctx);
365                         return NT_STATUS_ACCESS_DENIED;
366                 }
367         }
368
369         DEBUG(3,("Found account name from PAC: %s [%s]\n",
370                  logon_info->info3.base.account_name.string,
371                  logon_info->info3.base.full_name.string));
372
373         DEBUG(10,("Successfully validated Kerberos PAC\n"));
374
375         if (DEBUGLEVEL >= 10) {
376                 const char *s;
377                 s = NDR_PRINT_STRUCT_STRING(tmp_ctx, PAC_DATA, pac_data);
378                 if (s) {
379                         DEBUGADD(10,("%s\n", s));
380                 }
381         }
382
383         if (pac_data_out) {
384                 *pac_data_out = talloc_steal(mem_ctx, pac_data);
385         }
386
387         return NT_STATUS_OK;
388 }
389
390 #endif