Line data Source code
1 : /*
2 : Unix SMB/CIFS implementation.
3 : kerberos authorization data (PAC) utility library
4 : Copyright (C) Andrew Bartlett <abartlet@samba.org> 2011
5 : Copyright (C) Simo Sorce 2010.
6 :
7 : This program is free software; you can redistribute it and/or modify
8 : it under the terms of the GNU General Public License as published by
9 : the Free Software Foundation; either version 3 of the License, or
10 : (at your option) any later version.
11 :
12 : This program is distributed in the hope that it will be useful,
13 : but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : GNU General Public License for more details.
16 :
17 : You should have received a copy of the GNU General Public License
18 : along with this program. If not, see <http://www.gnu.org/licenses/>.
19 : */
20 :
21 : #include "includes.h"
22 :
23 : #undef DBGC_CLASS
24 : #define DBGC_CLASS DBGC_AUTH
25 :
26 : #ifdef HAVE_KRB5
27 :
28 : #include "auth/kerberos/pac_utils.h"
29 :
30 : #if 0
31 : /* FIXME - need proper configure/waf test
32 : * to determine if gss_mech_krb5 and friends
33 : * exist. JRA.
34 : */
35 : /*
36 : * These are not exported by Solaris -lkrb5
37 : * Maybe move to libreplace somewhere?
38 : */
39 : static const gss_OID_desc krb5_gss_oid_array[] = {
40 : /* this is the official, rfc-specified OID */
41 : { 9, "\052\206\110\206\367\022\001\002\002" },
42 : /* this is the pre-RFC mech OID */
43 : { 5, "\053\005\001\005\002" },
44 : /* this is the unofficial, incorrect mech OID emitted by MS */
45 : { 9, "\052\206\110\202\367\022\001\002\002" },
46 : { 0, 0 }
47 : };
48 :
49 : const gss_OID_desc * const gss_mech_krb5 = krb5_gss_oid_array+0;
50 : const gss_OID_desc * const gss_mech_krb5_old = krb5_gss_oid_array+1;
51 : const gss_OID_desc * const gss_mech_krb5_wrong = krb5_gss_oid_array+2;
52 : #endif
53 :
54 : #ifndef GSS_KRB5_INQ_SSPI_SESSION_KEY_OID
55 : #define GSS_KRB5_INQ_SSPI_SESSION_KEY_OID_LENGTH 11
56 : #define GSS_KRB5_INQ_SSPI_SESSION_KEY_OID "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x05\x05"
57 : #endif
58 :
59 : gss_OID_desc gse_sesskey_inq_oid = {
60 : GSS_KRB5_INQ_SSPI_SESSION_KEY_OID_LENGTH,
61 : discard_const(GSS_KRB5_INQ_SSPI_SESSION_KEY_OID)
62 : };
63 :
64 : #ifndef GSS_KRB5_SESSION_KEY_ENCTYPE_OID
65 : #define GSS_KRB5_SESSION_KEY_ENCTYPE_OID_LENGTH 10
66 : #define GSS_KRB5_SESSION_KEY_ENCTYPE_OID "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04"
67 : #endif
68 :
69 : gss_OID_desc gse_sesskeytype_oid = {
70 : GSS_KRB5_SESSION_KEY_ENCTYPE_OID_LENGTH,
71 : discard_const(GSS_KRB5_SESSION_KEY_ENCTYPE_OID)
72 : };
73 :
74 : /* The Heimdal OID for getting the PAC */
75 : #define EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID_LENGTH 8
76 : /* EXTRACTION OID AUTHZ ID */
77 : #define EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID "\x2a\x85\x70\x2b\x0d\x03" "\x81\x00"
78 :
79 32210 : NTSTATUS gssapi_obtain_pac_blob(TALLOC_CTX *mem_ctx,
80 : gss_ctx_id_t gssapi_context,
81 : gss_name_t gss_client_name,
82 : DATA_BLOB *pac_blob)
83 : {
84 881 : NTSTATUS status;
85 881 : OM_uint32 gss_maj, gss_min;
86 : #ifdef HAVE_GSS_GET_NAME_ATTRIBUTE
87 : /*
88 : * gss_get_name_attribute() in MIT krb5 1.10.0 can return uninitialized pac_display_buffer
89 : * and later gss_release_buffer() will crash on attempting to release it.
90 : *
91 : * So always initialize the buffer descriptors.
92 : *
93 : * See following links for more details:
94 : * http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=658514
95 : * http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=7087
96 : */
97 8432 : gss_buffer_desc pac_buffer = {
98 : .value = NULL,
99 : .length = 0
100 : };
101 8432 : gss_buffer_desc pac_display_buffer = {
102 : .value = NULL,
103 : .length = 0
104 : };
105 8432 : gss_buffer_desc pac_name = {
106 : .value = discard_const("urn:mspac:"),
107 : .length = sizeof("urn:mspac:")-1
108 : };
109 8432 : int more = -1;
110 8432 : int authenticated = false;
111 8432 : int complete = false;
112 :
113 8432 : gss_maj = gss_get_name_attribute(
114 : &gss_min, gss_client_name, &pac_name,
115 : &authenticated, &complete,
116 : &pac_buffer, &pac_display_buffer, &more);
117 :
118 8432 : if (gss_maj != 0) {
119 5 : gss_OID oid = discard_const(gss_mech_krb5);
120 5 : DBG_NOTICE("obtaining PAC via GSSAPI gss_get_name_attribute "
121 : "failed: %s\n", gssapi_error_string(mem_ctx,
122 : gss_maj, gss_min,
123 : oid));
124 5 : return NT_STATUS_ACCESS_DENIED;
125 8427 : } else if (authenticated && complete) {
126 : /* The PAC blob is returned directly */
127 8427 : *pac_blob = data_blob_talloc(mem_ctx, pac_buffer.value,
128 : pac_buffer.length);
129 :
130 8427 : if (!pac_blob->data) {
131 0 : status = NT_STATUS_NO_MEMORY;
132 : } else {
133 8427 : status = NT_STATUS_OK;
134 : }
135 :
136 8427 : gss_release_buffer(&gss_min, &pac_buffer);
137 8427 : gss_release_buffer(&gss_min, &pac_display_buffer);
138 8427 : return status;
139 : } else {
140 0 : DEBUG(0, ("obtaining PAC via GSSAPI failed: authenticated: %s, complete: %s, more: %s\n",
141 : authenticated ? "true" : "false",
142 : complete ? "true" : "false",
143 : more ? "true" : "false"));
144 0 : return NT_STATUS_ACCESS_DENIED;
145 : }
146 :
147 : #elif defined(HAVE_GSS_INQUIRE_SEC_CONTEXT_BY_OID)
148 23778 : gss_OID_desc pac_data_oid = {
149 : .elements = discard_const(EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID),
150 : .length = EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID_LENGTH
151 : };
152 :
153 23778 : gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
154 :
155 : /* If we didn't have the routine to get a verified, validated
156 : * PAC (supplied only by MIT at the time of writing), then try
157 : * with the Heimdal OID (fetches the PAC directly and always
158 : * validates) */
159 23778 : gss_maj = gss_inquire_sec_context_by_oid(
160 : &gss_min, gssapi_context,
161 : &pac_data_oid, &set);
162 :
163 : /* First check for the error MIT gives for an unknown OID */
164 23778 : if (gss_maj == GSS_S_UNAVAILABLE) {
165 0 : DEBUG(1, ("unable to obtain a PAC against this GSSAPI library. "
166 : "GSSAPI secured connections are available only with Heimdal or MIT Kerberos >= 1.8\n"));
167 23778 : } else if (gss_maj != 0) {
168 8 : DEBUG(2, ("obtaining PAC via GSSAPI gss_inquire_sec_context_by_oid (Heimdal OID) failed: %s\n",
169 : gssapi_error_string(mem_ctx, gss_maj, gss_min, gss_mech_krb5)));
170 : } else {
171 23770 : if (set == GSS_C_NO_BUFFER_SET) {
172 0 : DEBUG(0, ("gss_inquire_sec_context_by_oid returned unknown "
173 : "data in results.\n"));
174 0 : return NT_STATUS_INTERNAL_ERROR;
175 : }
176 :
177 : /* The PAC blob is returned directly */
178 23770 : *pac_blob = data_blob_talloc(mem_ctx, set->elements[0].value,
179 : set->elements[0].length);
180 23770 : if (!pac_blob->data) {
181 0 : status = NT_STATUS_NO_MEMORY;
182 : } else {
183 23770 : status = NT_STATUS_OK;
184 : }
185 :
186 23770 : gss_maj = gss_release_buffer_set(&gss_min, &set);
187 23770 : return status;
188 : }
189 : #else
190 : DEBUG(1, ("unable to obtain a PAC against this GSSAPI library. "
191 : "GSSAPI secured connections are available only with Heimdal or MIT Kerberos >= 1.8\n"));
192 : #endif
193 8 : return NT_STATUS_ACCESS_DENIED;
194 : }
195 :
196 87546 : NTSTATUS gssapi_get_session_key(TALLOC_CTX *mem_ctx,
197 : gss_ctx_id_t gssapi_context,
198 : DATA_BLOB *session_key,
199 : uint32_t *keytype)
200 : {
201 2510 : OM_uint32 gss_min, gss_maj;
202 87546 : gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
203 :
204 87546 : gss_maj = gss_inquire_sec_context_by_oid(
205 : &gss_min, gssapi_context,
206 : &gse_sesskey_inq_oid, &set);
207 87546 : if (gss_maj) {
208 0 : DEBUG(0, ("gss_inquire_sec_context_by_oid failed [%s]\n",
209 : gssapi_error_string(mem_ctx,
210 : gss_maj,
211 : gss_min,
212 : discard_const_p(struct gss_OID_desc_struct,
213 : gss_mech_krb5))));
214 0 : return NT_STATUS_NO_USER_SESSION_KEY;
215 : }
216 :
217 87546 : if ((set == GSS_C_NO_BUFFER_SET) ||
218 87546 : (set->count == 0)) {
219 : #ifdef HAVE_GSSKRB5_GET_SUBKEY
220 0 : krb5_keyblock *subkey;
221 0 : gss_maj = gsskrb5_get_subkey(&gss_min,
222 : gssapi_context,
223 : &subkey);
224 0 : if (gss_maj != 0) {
225 0 : DEBUG(1, ("NO session key for this mech\n"));
226 0 : return NT_STATUS_NO_USER_SESSION_KEY;
227 : }
228 0 : if (session_key) {
229 0 : *session_key = data_blob_talloc(mem_ctx,
230 : KRB5_KEY_DATA(subkey), KRB5_KEY_LENGTH(subkey));
231 : }
232 0 : if (keytype) {
233 0 : *keytype = KRB5_KEY_TYPE(subkey);
234 : }
235 0 : krb5_free_keyblock(NULL /* should be krb5_context */, subkey);
236 0 : return NT_STATUS_OK;
237 : #else
238 0 : DEBUG(0, ("gss_inquire_sec_context_by_oid didn't return any session key (and no alternative method available)\n"));
239 0 : return NT_STATUS_NO_USER_SESSION_KEY;
240 : #endif
241 : }
242 :
243 87546 : if (session_key) {
244 48865 : *session_key = data_blob_talloc(mem_ctx, set->elements[0].value,
245 : set->elements[0].length);
246 : }
247 :
248 87546 : if (keytype) {
249 978 : int diflen, i;
250 978 : const uint8_t *p;
251 :
252 38681 : *keytype = 0;
253 38681 : if (set->count < 2) {
254 :
255 : #ifdef HAVE_GSSKRB5_GET_SUBKEY
256 978 : krb5_keyblock *subkey;
257 29564 : gss_maj = gsskrb5_get_subkey(&gss_min,
258 : gssapi_context,
259 : &subkey);
260 29564 : if (gss_maj == 0) {
261 29564 : *keytype = KRB5_KEY_TYPE(subkey);
262 29564 : krb5_free_keyblock(NULL /* should be krb5_context */, subkey);
263 : }
264 : #endif
265 29564 : gss_release_buffer_set(&gss_min, &set);
266 :
267 29564 : return NT_STATUS_OK;
268 :
269 9117 : } else if (memcmp(set->elements[1].value,
270 9117 : gse_sesskeytype_oid.elements,
271 9117 : gse_sesskeytype_oid.length) != 0) {
272 : /* Perhaps a non-krb5 session key */
273 0 : gss_release_buffer_set(&gss_min, &set);
274 0 : return NT_STATUS_OK;
275 : }
276 9117 : p = (const uint8_t *)set->elements[1].value + gse_sesskeytype_oid.length;
277 9117 : diflen = set->elements[1].length - gse_sesskeytype_oid.length;
278 9117 : if (diflen <= 0) {
279 0 : gss_release_buffer_set(&gss_min, &set);
280 0 : return NT_STATUS_INVALID_PARAMETER;
281 : }
282 18234 : for (i = 0; i < diflen; i++) {
283 9117 : *keytype = (*keytype << 7) | (p[i] & 0x7f);
284 9117 : if (i + 1 != diflen && (p[i] & 0x80) == 0) {
285 0 : gss_release_buffer_set(&gss_min, &set);
286 0 : return NT_STATUS_INVALID_PARAMETER;
287 : }
288 : }
289 : }
290 :
291 57982 : gss_release_buffer_set(&gss_min, &set);
292 57982 : return NT_STATUS_OK;
293 : }
294 :
295 :
296 31 : char *gssapi_error_string(TALLOC_CTX *mem_ctx,
297 : OM_uint32 maj_stat, OM_uint32 min_stat,
298 : const gss_OID mech)
299 : {
300 0 : OM_uint32 disp_min_stat, disp_maj_stat;
301 0 : gss_buffer_desc maj_error_message;
302 0 : gss_buffer_desc min_error_message;
303 0 : char *maj_error_string, *min_error_string;
304 31 : OM_uint32 msg_ctx = 0;
305 :
306 0 : char *ret;
307 :
308 31 : maj_error_message.value = NULL;
309 31 : min_error_message.value = NULL;
310 31 : maj_error_message.length = 0;
311 31 : min_error_message.length = 0;
312 :
313 31 : disp_maj_stat = gss_display_status(&disp_min_stat, maj_stat,
314 : GSS_C_GSS_CODE, mech,
315 : &msg_ctx, &maj_error_message);
316 31 : if (disp_maj_stat != 0) {
317 0 : maj_error_message.value = NULL;
318 0 : maj_error_message.length = 0;
319 : }
320 31 : disp_maj_stat = gss_display_status(&disp_min_stat, min_stat,
321 : GSS_C_MECH_CODE, mech,
322 : &msg_ctx, &min_error_message);
323 31 : if (disp_maj_stat != 0) {
324 0 : min_error_message.value = NULL;
325 0 : min_error_message.length = 0;
326 : }
327 :
328 31 : maj_error_string = talloc_strndup(mem_ctx,
329 31 : (char *)maj_error_message.value,
330 : maj_error_message.length);
331 :
332 31 : min_error_string = talloc_strndup(mem_ctx,
333 31 : (char *)min_error_message.value,
334 : min_error_message.length);
335 :
336 31 : ret = talloc_asprintf(mem_ctx, "%s: %s",
337 : maj_error_string, min_error_string);
338 :
339 31 : talloc_free(maj_error_string);
340 31 : talloc_free(min_error_string);
341 :
342 31 : gss_release_buffer(&disp_min_stat, &maj_error_message);
343 31 : gss_release_buffer(&disp_min_stat, &min_error_message);
344 :
345 31 : return ret;
346 : }
347 :
348 : #endif /* HAVE_KRB5 */
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