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
31#include <sys/types.h>
32
33#include <stdarg.h>
34
35#include "xmalloc.h"
36#include "key.h"
37#include "hostfile.h"
38#include "auth.h"
39#include "ssh2.h"
40#include "log.h"
41#include "dispatch.h"
42#include "buffer.h"
43#include "servconf.h"
44#include "packet.h"
45#include "ssh-gss.h"
46#include "monitor_wrap.h"
47
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);
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 */
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"
38#include "auth.h"
39#include "ssh2.h"
40#include "log.h"
41#include "dispatch.h"
42#include "buffer.h"
43#include "servconf.h"
44#include "packet.h"
45#include "ssh-gss.h"
46#include "monitor_wrap.h"
47
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);
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 */