1/* $OpenBSD: auth2-gss.c,v 1.12 2005/10/13 22:24:31 stevesk Exp $ */
| 1/* $OpenBSD: auth2-gss.c,v 1.15 2006/08/03 03:34:41 deraadt Exp $ */
|
2
3/*
4 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "includes.h"
28
29#ifdef GSSAPI
30
| 2
3/*
4 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "includes.h"
28
29#ifdef GSSAPI
30
|
| 31#include <sys/types.h>
32
33#include <stdarg.h>
34
35#include "xmalloc.h"
36#include "key.h"
37#include "hostfile.h"
|
31#include "auth.h"
32#include "ssh2.h"
| 38#include "auth.h"
39#include "ssh2.h"
|
33#include "xmalloc.h"
| |
34#include "log.h"
35#include "dispatch.h"
| 40#include "log.h"
41#include "dispatch.h"
|
| 42#include "buffer.h"
|
36#include "servconf.h"
37#include "packet.h"
| 43#include "servconf.h"
44#include "packet.h"
|
| 45#include "ssh-gss.h"
|
38#include "monitor_wrap.h"
39
| 46#include "monitor_wrap.h"
47
|
40#include "ssh-gss.h"
41
| |
42extern ServerOptions options;
43
44static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
45static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
46static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
47static void input_gssapi_errtok(int, u_int32_t, void *);
48
49/*
50 * We only support those mechanisms that we know about (ie ones that we know
51 * how to check local user kuserok and the like)
52 */
53static int
54userauth_gssapi(Authctxt *authctxt)
55{
56 gss_OID_desc goid = {0, NULL};
57 Gssctxt *ctxt = NULL;
58 int mechs;
59 gss_OID_set supported;
60 int present;
61 OM_uint32 ms;
62 u_int len;
63 u_char *doid = NULL;
64
65 if (!authctxt->valid || authctxt->user == NULL)
66 return (0);
67
68 mechs = packet_get_int();
69 if (mechs == 0) {
70 debug("Mechanism negotiation is not supported");
71 return (0);
72 }
73
74 ssh_gssapi_supported_oids(&supported);
75 do {
76 mechs--;
77
78 if (doid)
79 xfree(doid);
80
81 present = 0;
82 doid = packet_get_string(&len);
83
84 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
85 doid[1] == len - 2) {
86 goid.elements = doid + 2;
87 goid.length = len - 2;
88 gss_test_oid_set_member(&ms, &goid, supported,
89 &present);
90 } else {
91 logit("Badly formed OID received");
92 }
93 } while (mechs > 0 && !present);
94
95 gss_release_oid_set(&ms, &supported);
96
97 if (!present) {
98 xfree(doid);
99 return (0);
100 }
101
102 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
| 48extern ServerOptions options;
49
50static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
51static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
52static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
53static void input_gssapi_errtok(int, u_int32_t, void *);
54
55/*
56 * We only support those mechanisms that we know about (ie ones that we know
57 * how to check local user kuserok and the like)
58 */
59static int
60userauth_gssapi(Authctxt *authctxt)
61{
62 gss_OID_desc goid = {0, NULL};
63 Gssctxt *ctxt = NULL;
64 int mechs;
65 gss_OID_set supported;
66 int present;
67 OM_uint32 ms;
68 u_int len;
69 u_char *doid = NULL;
70
71 if (!authctxt->valid || authctxt->user == NULL)
72 return (0);
73
74 mechs = packet_get_int();
75 if (mechs == 0) {
76 debug("Mechanism negotiation is not supported");
77 return (0);
78 }
79
80 ssh_gssapi_supported_oids(&supported);
81 do {
82 mechs--;
83
84 if (doid)
85 xfree(doid);
86
87 present = 0;
88 doid = packet_get_string(&len);
89
90 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
91 doid[1] == len - 2) {
92 goid.elements = doid + 2;
93 goid.length = len - 2;
94 gss_test_oid_set_member(&ms, &goid, supported,
95 &present);
96 } else {
97 logit("Badly formed OID received");
98 }
99 } while (mechs > 0 && !present);
100
101 gss_release_oid_set(&ms, &supported);
102
103 if (!present) {
104 xfree(doid);
105 return (0);
106 }
107
108 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
|
| 109 if (ctxt != NULL)
110 ssh_gssapi_delete_ctx(&ctxt);
|
103 xfree(doid);
104 return (0);
105 }
106
107 authctxt->methoddata = (void *)ctxt;
108
109 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
110
111 /* Return the OID that we received */
112 packet_put_string(doid, len);
113
114 packet_send();
115 xfree(doid);
116
117 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
118 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
119 authctxt->postponed = 1;
120
121 return (0);
122}
123
124static void
125input_gssapi_token(int type, u_int32_t plen, void *ctxt)
126{
127 Authctxt *authctxt = ctxt;
128 Gssctxt *gssctxt;
129 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
130 gss_buffer_desc recv_tok;
131 OM_uint32 maj_status, min_status, flags;
132 u_int len;
133
134 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
135 fatal("No authentication or GSSAPI context");
136
137 gssctxt = authctxt->methoddata;
138 recv_tok.value = packet_get_string(&len);
139 recv_tok.length = len; /* u_int vs. size_t */
140
141 packet_check_eom();
142
143 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
144 &send_tok, &flags));
145
146 xfree(recv_tok.value);
147
148 if (GSS_ERROR(maj_status)) {
149 if (send_tok.length != 0) {
150 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
151 packet_put_string(send_tok.value, send_tok.length);
152 packet_send();
153 }
154 authctxt->postponed = 0;
155 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
156 userauth_finish(authctxt, 0, "gssapi-with-mic");
157 } else {
158 if (send_tok.length != 0) {
159 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
160 packet_put_string(send_tok.value, send_tok.length);
161 packet_send();
162 }
163 if (maj_status == GSS_S_COMPLETE) {
164 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
165 if (flags & GSS_C_INTEG_FLAG)
166 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
167 &input_gssapi_mic);
168 else
169 dispatch_set(
170 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
171 &input_gssapi_exchange_complete);
172 }
173 }
174
175 gss_release_buffer(&min_status, &send_tok);
176}
177
178static void
179input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
180{
181 Authctxt *authctxt = ctxt;
182 Gssctxt *gssctxt;
183 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
184 gss_buffer_desc recv_tok;
185 OM_uint32 maj_status;
186 u_int len;
187
188 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
189 fatal("No authentication or GSSAPI context");
190
191 gssctxt = authctxt->methoddata;
192 recv_tok.value = packet_get_string(&len);
193 recv_tok.length = len;
194
195 packet_check_eom();
196
197 /* Push the error token into GSSAPI to see what it says */
198 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
199 &send_tok, NULL));
200
201 xfree(recv_tok.value);
202
203 /* We can't return anything to the client, even if we wanted to */
204 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
205 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
206
207 /* The client will have already moved on to the next auth */
208
209 gss_release_buffer(&maj_status, &send_tok);
210}
211
212/*
213 * This is called when the client thinks we've completed authentication.
214 * It should only be enabled in the dispatch handler by the function above,
215 * which only enables it once the GSSAPI exchange is complete.
216 */
217
218static void
219input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
220{
221 Authctxt *authctxt = ctxt;
222 Gssctxt *gssctxt;
223 int authenticated;
224
225 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
226 fatal("No authentication or GSSAPI context");
227
228 gssctxt = authctxt->methoddata;
229
230 /*
231 * We don't need to check the status, because we're only enabled in
232 * the dispatcher once the exchange is complete
233 */
234
235 packet_check_eom();
236
237 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
238
239 authctxt->postponed = 0;
240 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
241 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
242 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
243 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
244 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
245}
246
247static void
248input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
249{
250 Authctxt *authctxt = ctxt;
251 Gssctxt *gssctxt;
252 int authenticated = 0;
253 Buffer b;
254 gss_buffer_desc mic, gssbuf;
255 u_int len;
256
257 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
258 fatal("No authentication or GSSAPI context");
259
260 gssctxt = authctxt->methoddata;
261
262 mic.value = packet_get_string(&len);
263 mic.length = len;
264
265 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
266 "gssapi-with-mic");
267
268 gssbuf.value = buffer_ptr(&b);
269 gssbuf.length = buffer_len(&b);
270
271 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
272 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
273 else
274 logit("GSSAPI MIC check failed");
275
276 buffer_free(&b);
277 xfree(mic.value);
278
279 authctxt->postponed = 0;
280 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
281 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
282 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
283 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
284 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
285}
286
287Authmethod method_gssapi = {
288 "gssapi-with-mic",
289 userauth_gssapi,
290 &options.gss_authentication
291};
292
293#endif /* GSSAPI */
| 111 xfree(doid);
112 return (0);
113 }
114
115 authctxt->methoddata = (void *)ctxt;
116
117 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
118
119 /* Return the OID that we received */
120 packet_put_string(doid, len);
121
122 packet_send();
123 xfree(doid);
124
125 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
126 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
127 authctxt->postponed = 1;
128
129 return (0);
130}
131
132static void
133input_gssapi_token(int type, u_int32_t plen, void *ctxt)
134{
135 Authctxt *authctxt = ctxt;
136 Gssctxt *gssctxt;
137 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
138 gss_buffer_desc recv_tok;
139 OM_uint32 maj_status, min_status, flags;
140 u_int len;
141
142 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
143 fatal("No authentication or GSSAPI context");
144
145 gssctxt = authctxt->methoddata;
146 recv_tok.value = packet_get_string(&len);
147 recv_tok.length = len; /* u_int vs. size_t */
148
149 packet_check_eom();
150
151 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
152 &send_tok, &flags));
153
154 xfree(recv_tok.value);
155
156 if (GSS_ERROR(maj_status)) {
157 if (send_tok.length != 0) {
158 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
159 packet_put_string(send_tok.value, send_tok.length);
160 packet_send();
161 }
162 authctxt->postponed = 0;
163 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
164 userauth_finish(authctxt, 0, "gssapi-with-mic");
165 } else {
166 if (send_tok.length != 0) {
167 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
168 packet_put_string(send_tok.value, send_tok.length);
169 packet_send();
170 }
171 if (maj_status == GSS_S_COMPLETE) {
172 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
173 if (flags & GSS_C_INTEG_FLAG)
174 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
175 &input_gssapi_mic);
176 else
177 dispatch_set(
178 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
179 &input_gssapi_exchange_complete);
180 }
181 }
182
183 gss_release_buffer(&min_status, &send_tok);
184}
185
186static void
187input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
188{
189 Authctxt *authctxt = ctxt;
190 Gssctxt *gssctxt;
191 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
192 gss_buffer_desc recv_tok;
193 OM_uint32 maj_status;
194 u_int len;
195
196 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
197 fatal("No authentication or GSSAPI context");
198
199 gssctxt = authctxt->methoddata;
200 recv_tok.value = packet_get_string(&len);
201 recv_tok.length = len;
202
203 packet_check_eom();
204
205 /* Push the error token into GSSAPI to see what it says */
206 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
207 &send_tok, NULL));
208
209 xfree(recv_tok.value);
210
211 /* We can't return anything to the client, even if we wanted to */
212 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
213 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
214
215 /* The client will have already moved on to the next auth */
216
217 gss_release_buffer(&maj_status, &send_tok);
218}
219
220/*
221 * This is called when the client thinks we've completed authentication.
222 * It should only be enabled in the dispatch handler by the function above,
223 * which only enables it once the GSSAPI exchange is complete.
224 */
225
226static void
227input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
228{
229 Authctxt *authctxt = ctxt;
230 Gssctxt *gssctxt;
231 int authenticated;
232
233 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
234 fatal("No authentication or GSSAPI context");
235
236 gssctxt = authctxt->methoddata;
237
238 /*
239 * We don't need to check the status, because we're only enabled in
240 * the dispatcher once the exchange is complete
241 */
242
243 packet_check_eom();
244
245 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
246
247 authctxt->postponed = 0;
248 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
249 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
250 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
251 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
252 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
253}
254
255static void
256input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
257{
258 Authctxt *authctxt = ctxt;
259 Gssctxt *gssctxt;
260 int authenticated = 0;
261 Buffer b;
262 gss_buffer_desc mic, gssbuf;
263 u_int len;
264
265 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
266 fatal("No authentication or GSSAPI context");
267
268 gssctxt = authctxt->methoddata;
269
270 mic.value = packet_get_string(&len);
271 mic.length = len;
272
273 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
274 "gssapi-with-mic");
275
276 gssbuf.value = buffer_ptr(&b);
277 gssbuf.length = buffer_len(&b);
278
279 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
280 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
281 else
282 logit("GSSAPI MIC check failed");
283
284 buffer_free(&b);
285 xfree(mic.value);
286
287 authctxt->postponed = 0;
288 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
289 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
290 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
291 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
292 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
293}
294
295Authmethod method_gssapi = {
296 "gssapi-with-mic",
297 userauth_gssapi,
298 &options.gss_authentication
299};
300
301#endif /* GSSAPI */
|