source: vendor/current/auth/kerberos/kerberos_pac.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 12.5 KB
Line 
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 "auth/kerberos/pac_utils.h"
30
31krb5_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 krb5_boolean checksum_valid = false;
40 krb5_data input;
41
42#ifdef HAVE_CHECKSUM_IN_KRB5_CHECKSUM /* Heimdal */
43 cksum.cksumtype = (krb5_cksumtype)sig->type;
44 cksum.checksum.length = sig->signature.length;
45 cksum.checksum.data = sig->signature.data;
46#else /* MIT */
47 cksum.checksum_type = (krb5_cksumtype)sig->type;
48 cksum.length = sig->signature.length;
49 cksum.contents = sig->signature.data;
50#endif
51
52#ifdef HAVE_KRB5_KU_OTHER_CKSUM /* Heimdal */
53 usage = KRB5_KU_OTHER_CKSUM;
54#elif defined(HAVE_KRB5_KEYUSAGE_APP_DATA_CKSUM) /* MIT */
55 usage = KRB5_KEYUSAGE_APP_DATA_CKSUM;
56#else
57#error UNKNOWN_KRB5_KEYUSAGE
58#endif
59
60 input.data = (char *)pac_data.data;
61 input.length = pac_data.length;
62
63 ret = krb5_c_verify_checksum(context,
64 keyblock,
65 usage,
66 &input,
67 &cksum,
68 &checksum_valid);
69 if (!checksum_valid) {
70 ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
71 }
72 if (ret){
73 DEBUG(2,("check_pac_checksum: PAC Verification failed: %s (%d)\n",
74 error_message(ret), ret));
75 return ret;
76 }
77
78 return ret;
79}
80
81/**
82* @brief Decode a blob containing a NDR encoded PAC structure
83*
84* @param mem_ctx - The memory context
85* @param pac_data_blob - The data blob containing the NDR encoded data
86* @param context - The Kerberos Context
87* @param service_keyblock - The Service Key used to verify the checksum
88* @param client_principal - The client principal
89* @param tgs_authtime - The ticket timestamp
90* @param pac_data_out - [out] The decoded PAC
91*
92* @return - A NTSTATUS error code
93*/
94NTSTATUS kerberos_decode_pac(TALLOC_CTX *mem_ctx,
95 DATA_BLOB pac_data_blob,
96 krb5_context context,
97 const krb5_keyblock *krbtgt_keyblock,
98 const krb5_keyblock *service_keyblock,
99 krb5_const_principal client_principal,
100 time_t tgs_authtime,
101 struct PAC_DATA **pac_data_out)
102{
103 NTSTATUS status;
104 enum ndr_err_code ndr_err;
105 krb5_error_code ret;
106 DATA_BLOB modified_pac_blob;
107
108 NTTIME tgs_authtime_nttime;
109 int i;
110
111 struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
112 struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
113 struct PAC_SIGNATURE_DATA *srv_sig_wipe = NULL;
114 struct PAC_SIGNATURE_DATA *kdc_sig_wipe = NULL;
115 struct PAC_LOGON_NAME *logon_name = NULL;
116 struct PAC_LOGON_INFO *logon_info = NULL;
117 struct PAC_DATA *pac_data = NULL;
118 struct PAC_DATA_RAW *pac_data_raw = NULL;
119
120 DATA_BLOB *srv_sig_blob = NULL;
121 DATA_BLOB *kdc_sig_blob = NULL;
122
123 bool bool_ret;
124
125 TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
126 if (!tmp_ctx) {
127 return NT_STATUS_NO_MEMORY;
128 }
129
130 if (pac_data_out) {
131 *pac_data_out = NULL;
132 }
133
134 pac_data = talloc(tmp_ctx, struct PAC_DATA);
135 pac_data_raw = talloc(tmp_ctx, struct PAC_DATA_RAW);
136 kdc_sig_wipe = talloc(tmp_ctx, struct PAC_SIGNATURE_DATA);
137 srv_sig_wipe = talloc(tmp_ctx, struct PAC_SIGNATURE_DATA);
138 if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
139 talloc_free(tmp_ctx);
140 return NT_STATUS_NO_MEMORY;
141 }
142
143 ndr_err = ndr_pull_struct_blob(&pac_data_blob, pac_data, pac_data,
144 (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
145 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
146 status = ndr_map_error2ntstatus(ndr_err);
147 DEBUG(0,("can't parse the PAC: %s\n",
148 nt_errstr(status)));
149 talloc_free(tmp_ctx);
150 return status;
151 }
152
153 if (pac_data->num_buffers < 4) {
154 /* we need logon_ingo, service_key and kdc_key */
155 DEBUG(0,("less than 4 PAC buffers\n"));
156 talloc_free(tmp_ctx);
157 return NT_STATUS_INVALID_PARAMETER;
158 }
159
160 ndr_err = ndr_pull_struct_blob(
161 &pac_data_blob, pac_data_raw, pac_data_raw,
162 (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA_RAW);
163 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
164 status = ndr_map_error2ntstatus(ndr_err);
165 DEBUG(0,("can't parse the PAC: %s\n",
166 nt_errstr(status)));
167 talloc_free(tmp_ctx);
168 return status;
169 }
170
171 if (pac_data_raw->num_buffers < 4) {
172 /* we need logon_ingo, service_key and kdc_key */
173 DEBUG(0,("less than 4 PAC buffers\n"));
174 talloc_free(tmp_ctx);
175 return NT_STATUS_INVALID_PARAMETER;
176 }
177
178 if (pac_data->num_buffers != pac_data_raw->num_buffers) {
179 /* we need logon_ingo, service_key and kdc_key */
180 DEBUG(0, ("misparse! PAC_DATA has %d buffers while "
181 "PAC_DATA_RAW has %d\n", pac_data->num_buffers,
182 pac_data_raw->num_buffers));
183 talloc_free(tmp_ctx);
184 return NT_STATUS_INVALID_PARAMETER;
185 }
186
187 for (i=0; i < pac_data->num_buffers; i++) {
188 struct PAC_BUFFER *data_buf = &pac_data->buffers[i];
189 struct PAC_BUFFER_RAW *raw_buf = &pac_data_raw->buffers[i];
190
191 if (data_buf->type != raw_buf->type) {
192 DEBUG(0, ("misparse! PAC_DATA buffer %d has type "
193 "%d while PAC_DATA_RAW has %d\n", i,
194 data_buf->type, raw_buf->type));
195 talloc_free(tmp_ctx);
196 return NT_STATUS_INVALID_PARAMETER;
197 }
198 switch (data_buf->type) {
199 case PAC_TYPE_LOGON_INFO:
200 if (!data_buf->info) {
201 break;
202 }
203 logon_info = data_buf->info->logon_info.info;
204 break;
205 case PAC_TYPE_SRV_CHECKSUM:
206 if (!data_buf->info) {
207 break;
208 }
209 srv_sig_ptr = &data_buf->info->srv_cksum;
210 srv_sig_blob = &raw_buf->info->remaining;
211 break;
212 case PAC_TYPE_KDC_CHECKSUM:
213 if (!data_buf->info) {
214 break;
215 }
216 kdc_sig_ptr = &data_buf->info->kdc_cksum;
217 kdc_sig_blob = &raw_buf->info->remaining;
218 break;
219 case PAC_TYPE_LOGON_NAME:
220 logon_name = &data_buf->info->logon_name;
221 break;
222 default:
223 break;
224 }
225 }
226
227 if (!logon_info) {
228 DEBUG(0,("PAC no logon_info\n"));
229 talloc_free(tmp_ctx);
230 return NT_STATUS_INVALID_PARAMETER;
231 }
232
233 if (!logon_name) {
234 DEBUG(0,("PAC no logon_name\n"));
235 talloc_free(tmp_ctx);
236 return NT_STATUS_INVALID_PARAMETER;
237 }
238
239 if (!srv_sig_ptr || !srv_sig_blob) {
240 DEBUG(0,("PAC no srv_key\n"));
241 talloc_free(tmp_ctx);
242 return NT_STATUS_INVALID_PARAMETER;
243 }
244
245 if (!kdc_sig_ptr || !kdc_sig_blob) {
246 DEBUG(0,("PAC no kdc_key\n"));
247 talloc_free(tmp_ctx);
248 return NT_STATUS_INVALID_PARAMETER;
249 }
250
251 /* Find and zero out the signatures,
252 * as required by the signing algorithm */
253
254 /* We find the data blobs above,
255 * now we parse them to get at the exact portion we should zero */
256 ndr_err = ndr_pull_struct_blob(
257 kdc_sig_blob, kdc_sig_wipe, kdc_sig_wipe,
258 (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
259 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
260 status = ndr_map_error2ntstatus(ndr_err);
261 DEBUG(0,("can't parse the KDC signature: %s\n",
262 nt_errstr(status)));
263 talloc_free(tmp_ctx);
264 return status;
265 }
266
267 ndr_err = ndr_pull_struct_blob(
268 srv_sig_blob, srv_sig_wipe, srv_sig_wipe,
269 (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
270 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
271 status = ndr_map_error2ntstatus(ndr_err);
272 DEBUG(0,("can't parse the SRV signature: %s\n",
273 nt_errstr(status)));
274 talloc_free(tmp_ctx);
275 return status;
276 }
277
278 /* Now zero the decoded structure */
279 memset(kdc_sig_wipe->signature.data,
280 '\0', kdc_sig_wipe->signature.length);
281 memset(srv_sig_wipe->signature.data,
282 '\0', srv_sig_wipe->signature.length);
283
284 /* and reencode, back into the same place it came from */
285 ndr_err = ndr_push_struct_blob(
286 kdc_sig_blob, pac_data_raw, kdc_sig_wipe,
287 (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
288 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
289 status = ndr_map_error2ntstatus(ndr_err);
290 DEBUG(0,("can't repack the KDC signature: %s\n",
291 nt_errstr(status)));
292 talloc_free(tmp_ctx);
293 return status;
294 }
295 ndr_err = ndr_push_struct_blob(
296 srv_sig_blob, pac_data_raw, srv_sig_wipe,
297 (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
298 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
299 status = ndr_map_error2ntstatus(ndr_err);
300 DEBUG(0,("can't repack the SRV signature: %s\n",
301 nt_errstr(status)));
302 talloc_free(tmp_ctx);
303 return status;
304 }
305
306 /* push out the whole structure, but now with zero'ed signatures */
307 ndr_err = ndr_push_struct_blob(
308 &modified_pac_blob, pac_data_raw, pac_data_raw,
309 (ndr_push_flags_fn_t)ndr_push_PAC_DATA_RAW);
310 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
311 status = ndr_map_error2ntstatus(ndr_err);
312 DEBUG(0,("can't repack the RAW PAC: %s\n",
313 nt_errstr(status)));
314 talloc_free(tmp_ctx);
315 return status;
316 }
317
318 if (service_keyblock) {
319 /* verify by service_key */
320 ret = check_pac_checksum(modified_pac_blob, srv_sig_ptr,
321 context,
322 service_keyblock);
323 if (ret) {
324 DEBUG(5, ("PAC Decode: Failed to verify the service "
325 "signature: %s\n", error_message(ret)));
326 return NT_STATUS_ACCESS_DENIED;
327 }
328
329 if (krbtgt_keyblock) {
330 /* verify the service key checksum by krbtgt_key */
331 ret = check_pac_checksum(srv_sig_ptr->signature, kdc_sig_ptr,
332 context, krbtgt_keyblock);
333 if (ret) {
334 DEBUG(1, ("PAC Decode: Failed to verify the KDC signature: %s\n",
335 smb_get_krb5_error_message(context, ret, tmp_ctx)));
336 talloc_free(tmp_ctx);
337 return NT_STATUS_ACCESS_DENIED;
338 }
339 }
340 }
341
342 if (tgs_authtime) {
343 /* Convert to NT time, so as not to loose accuracy in comparison */
344 unix_to_nt_time(&tgs_authtime_nttime, tgs_authtime);
345
346 if (tgs_authtime_nttime != logon_name->logon_time) {
347 DEBUG(2, ("PAC Decode: "
348 "Logon time mismatch between ticket and PAC!\n"));
349 DEBUG(2, ("PAC Decode: PAC: %s\n",
350 nt_time_string(tmp_ctx, logon_name->logon_time)));
351 DEBUG(2, ("PAC Decode: Ticket: %s\n",
352 nt_time_string(tmp_ctx, tgs_authtime_nttime)));
353 talloc_free(tmp_ctx);
354 return NT_STATUS_ACCESS_DENIED;
355 }
356 }
357
358 if (client_principal) {
359 char *client_principal_string;
360 ret = krb5_unparse_name_flags(context, client_principal,
361 KRB5_PRINCIPAL_UNPARSE_NO_REALM|KRB5_PRINCIPAL_UNPARSE_DISPLAY,
362 &client_principal_string);
363 if (ret) {
364 DEBUG(2, ("Could not unparse name from ticket to match with name from PAC: [%s]:%s\n",
365 logon_name->account_name, error_message(ret)));
366 talloc_free(tmp_ctx);
367 return NT_STATUS_INVALID_PARAMETER;
368 }
369
370 bool_ret = strcmp(client_principal_string, logon_name->account_name) == 0;
371
372 if (!bool_ret) {
373 DEBUG(2, ("Name in PAC [%s] does not match principal name "
374 "in ticket [%s]\n",
375 logon_name->account_name,
376 client_principal_string));
377 SAFE_FREE(client_principal_string);
378 talloc_free(tmp_ctx);
379 return NT_STATUS_ACCESS_DENIED;
380 }
381 SAFE_FREE(client_principal_string);
382
383 }
384
385 DEBUG(3,("Found account name from PAC: %s [%s]\n",
386 logon_info->info3.base.account_name.string,
387 logon_info->info3.base.full_name.string));
388
389 DEBUG(10,("Successfully validated Kerberos PAC\n"));
390
391 if (DEBUGLEVEL >= 10) {
392 const char *s;
393 s = NDR_PRINT_STRUCT_STRING(tmp_ctx, PAC_DATA, pac_data);
394 if (s) {
395 DEBUGADD(10,("%s\n", s));
396 }
397 }
398
399 if (pac_data_out) {
400 *pac_data_out = talloc_steal(mem_ctx, pac_data);
401 }
402
403 return NT_STATUS_OK;
404}
405
406NTSTATUS kerberos_pac_logon_info(TALLOC_CTX *mem_ctx,
407 DATA_BLOB blob,
408 krb5_context context,
409 const krb5_keyblock *krbtgt_keyblock,
410 const krb5_keyblock *service_keyblock,
411 krb5_const_principal client_principal,
412 time_t tgs_authtime,
413 struct PAC_LOGON_INFO **logon_info)
414{
415 NTSTATUS nt_status;
416 struct PAC_DATA *pac_data;
417 int i;
418 nt_status = kerberos_decode_pac(mem_ctx,
419 blob,
420 context,
421 krbtgt_keyblock,
422 service_keyblock,
423 client_principal,
424 tgs_authtime,
425 &pac_data);
426 if (!NT_STATUS_IS_OK(nt_status)) {
427 return nt_status;
428 }
429
430 *logon_info = NULL;
431 for (i=0; i < pac_data->num_buffers; i++) {
432 if (pac_data->buffers[i].type != PAC_TYPE_LOGON_INFO) {
433 continue;
434 }
435 *logon_info = pac_data->buffers[i].info->logon_info.info;
436 }
437 if (!*logon_info) {
438 return NT_STATUS_INVALID_PARAMETER;
439 }
440 return NT_STATUS_OK;
441}
442
443#endif
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