1 /* $OpenBSD: auth2-gss.c,v 1.15 2006/08/03 03:34:41 deraadt Exp $ */
4 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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.
31 #include <sys/types.h>
46 #include "monitor_wrap.h"
48 extern ServerOptions options;
50 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
51 static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
52 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
53 static void input_gssapi_errtok(int, u_int32_t, void *);
56 * The 'gssapi_keyex' userauth mechanism.
59 userauth_gsskeyex(Authctxt *authctxt)
61 int authenticated = 0;
63 gss_buffer_desc mic, gssbuf;
66 mic.value = packet_get_string(&len);
71 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
74 gssbuf.value = buffer_ptr(&b);
75 gssbuf.length = buffer_len(&b);
77 /* gss_kex_context is NULL with privsep, so we can't check it here */
78 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
80 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
85 return (authenticated);
89 * We only support those mechanisms that we know about (ie ones that we know
90 * how to check local user kuserok and the like)
93 userauth_gssapi(Authctxt *authctxt)
95 gss_OID_desc goid = {0, NULL};
98 gss_OID_set supported;
104 if (!authctxt->valid || authctxt->user == NULL)
107 mechs = packet_get_int();
109 debug("Mechanism negotiation is not supported");
113 ssh_gssapi_supported_oids(&supported);
121 doid = packet_get_string(&len);
123 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
124 doid[1] == len - 2) {
125 goid.elements = doid + 2;
126 goid.length = len - 2;
127 gss_test_oid_set_member(&ms, &goid, supported,
130 logit("Badly formed OID received");
132 } while (mechs > 0 && !present);
134 gss_release_oid_set(&ms, &supported);
138 authctxt->server_caused_failure = 1;
142 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
144 ssh_gssapi_delete_ctx(&ctxt);
146 authctxt->server_caused_failure = 1;
150 authctxt->methoddata = (void *)ctxt;
152 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
154 /* Return the OID that we received */
155 packet_put_string(doid, len);
160 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
161 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
162 authctxt->postponed = 1;
168 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
170 Authctxt *authctxt = ctxt;
172 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
173 gss_buffer_desc recv_tok;
174 OM_uint32 maj_status, min_status, flags;
177 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
178 fatal("No authentication or GSSAPI context");
180 gssctxt = authctxt->methoddata;
181 recv_tok.value = packet_get_string(&len);
182 recv_tok.length = len; /* u_int vs. size_t */
186 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
189 xfree(recv_tok.value);
191 if (GSS_ERROR(maj_status)) {
192 if (send_tok.length != 0) {
193 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
194 packet_put_string(send_tok.value, send_tok.length);
197 authctxt->postponed = 0;
198 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
199 userauth_finish(authctxt, 0, "gssapi-with-mic");
201 if (send_tok.length != 0) {
202 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
203 packet_put_string(send_tok.value, send_tok.length);
206 if (maj_status == GSS_S_COMPLETE) {
207 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
208 if (flags & GSS_C_INTEG_FLAG)
209 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
213 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
214 &input_gssapi_exchange_complete);
218 gss_release_buffer(&min_status, &send_tok);
222 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
224 Authctxt *authctxt = ctxt;
226 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
227 gss_buffer_desc recv_tok;
228 OM_uint32 maj_status;
231 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
232 fatal("No authentication or GSSAPI context");
234 gssctxt = authctxt->methoddata;
235 recv_tok.value = packet_get_string(&len);
236 recv_tok.length = len;
240 /* Push the error token into GSSAPI to see what it says */
241 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
244 xfree(recv_tok.value);
246 /* We can't return anything to the client, even if we wanted to */
247 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
248 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
250 /* The client will have already moved on to the next auth */
252 gss_release_buffer(&maj_status, &send_tok);
256 * This is called when the client thinks we've completed authentication.
257 * It should only be enabled in the dispatch handler by the function above,
258 * which only enables it once the GSSAPI exchange is complete.
262 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
264 Authctxt *authctxt = ctxt;
268 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
269 fatal("No authentication or GSSAPI context");
271 gssctxt = authctxt->methoddata;
274 * We don't need to check the status, because we're only enabled in
275 * the dispatcher once the exchange is complete
280 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
282 authctxt->postponed = 0;
283 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
284 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
285 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
286 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
287 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
291 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
293 Authctxt *authctxt = ctxt;
295 int authenticated = 0;
297 gss_buffer_desc mic, gssbuf;
300 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
301 fatal("No authentication or GSSAPI context");
303 gssctxt = authctxt->methoddata;
305 mic.value = packet_get_string(&len);
308 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
311 gssbuf.value = buffer_ptr(&b);
312 gssbuf.length = buffer_len(&b);
314 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
315 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
317 logit("GSSAPI MIC check failed");
322 authctxt->postponed = 0;
323 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
324 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
325 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
326 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
327 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
330 Authmethod method_gsskeyex = {
333 &options.gss_authentication
336 Authmethod method_gssapi = {
339 &options.gss_authentication