1 /* $OpenBSD: auth2-gss.c,v 1.16 2007/10/29 00:52:45 dtucker Exp $ */
4 * Copyright (c) 2001-2007 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,
86 return (authenticated);
90 * We only support those mechanisms that we know about (ie ones that we know
91 * how to check local user kuserok and the like)
94 userauth_gssapi(Authctxt *authctxt)
96 gss_OID_desc goid = {0, NULL};
99 gss_OID_set supported;
105 /* authctxt->valid may be 0 if we haven't yet determined
106 username from gssapi context. */
108 if (authctxt->user == NULL)
111 mechs = packet_get_int();
113 debug("Mechanism negotiation is not supported");
117 ssh_gssapi_supported_oids(&supported);
125 doid = packet_get_string(&len);
127 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
128 doid[1] == len - 2) {
129 goid.elements = doid + 2;
130 goid.length = len - 2;
131 gss_test_oid_set_member(&ms, &goid, supported,
134 logit("Badly formed OID received");
136 } while (mechs > 0 && !present);
138 gss_release_oid_set(&ms, &supported);
142 authctxt->server_caused_failure = 1;
146 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
148 ssh_gssapi_delete_ctx(&ctxt);
150 authctxt->server_caused_failure = 1;
154 authctxt->methoddata = (void *)ctxt;
156 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
158 /* Return the OID that we received */
159 packet_put_string(doid, len);
164 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
165 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
166 authctxt->postponed = 1;
172 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
174 Authctxt *authctxt = ctxt;
176 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
177 gss_buffer_desc recv_tok;
178 OM_uint32 maj_status, min_status, flags;
181 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
182 fatal("No authentication or GSSAPI context");
184 gssctxt = authctxt->methoddata;
185 recv_tok.value = packet_get_string(&len);
186 recv_tok.length = len; /* u_int vs. size_t */
190 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
193 xfree(recv_tok.value);
195 if (GSS_ERROR(maj_status)) {
196 if (send_tok.length != 0) {
197 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
198 packet_put_string(send_tok.value, send_tok.length);
201 authctxt->postponed = 0;
202 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
203 userauth_finish(authctxt, 0, "gssapi-with-mic");
205 if (send_tok.length != 0) {
206 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
207 packet_put_string(send_tok.value, send_tok.length);
210 if (maj_status == GSS_S_COMPLETE) {
211 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
212 if (flags & GSS_C_INTEG_FLAG)
213 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
217 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
218 &input_gssapi_exchange_complete);
222 gss_release_buffer(&min_status, &send_tok);
226 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
228 Authctxt *authctxt = ctxt;
230 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
231 gss_buffer_desc recv_tok;
232 OM_uint32 maj_status;
235 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
236 fatal("No authentication or GSSAPI context");
238 gssctxt = authctxt->methoddata;
239 recv_tok.value = packet_get_string(&len);
240 recv_tok.length = len;
244 /* Push the error token into GSSAPI to see what it says */
245 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
248 xfree(recv_tok.value);
250 /* We can't return anything to the client, even if we wanted to */
251 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
252 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
254 /* The client will have already moved on to the next auth */
256 gss_release_buffer(&maj_status, &send_tok);
260 gssapi_set_username(Authctxt *authctxt)
264 if ((authctxt->user == NULL) || (authctxt->user[0] == '\0')) {
265 PRIVSEP(ssh_gssapi_localname(&lname));
266 if (lname && lname[0] != '\0') {
267 if (authctxt->user) xfree(authctxt->user);
268 authctxt->user = lname;
269 debug("set username to %s from gssapi context", lname);
270 authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
275 PRIVSEP(start_pam(authctxt));
279 debug("failed to set username from gssapi context");
280 packet_send_debug("failed to set username from gssapi context");
286 * This is called when the client thinks we've completed authentication.
287 * It should only be enabled in the dispatch handler by the function above,
288 * which only enables it once the GSSAPI exchange is complete.
292 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
294 Authctxt *authctxt = ctxt;
298 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
299 fatal("No authentication or GSSAPI context");
301 gssctxt = authctxt->methoddata;
304 * We don't need to check the status, because we're only enabled in
305 * the dispatcher once the exchange is complete
310 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
313 authctxt->postponed = 0;
314 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
315 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
316 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
317 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
318 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
322 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
324 Authctxt *authctxt = ctxt;
326 int authenticated = 0;
328 gss_buffer_desc mic, gssbuf;
331 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
332 fatal("No authentication or GSSAPI context");
334 gssctxt = authctxt->methoddata;
336 mic.value = packet_get_string(&len);
339 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
342 gssbuf.value = buffer_ptr(&b);
343 gssbuf.length = buffer_len(&b);
345 gssapi_set_username(authctxt);
347 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
349 PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw));
351 logit("GSSAPI MIC check failed");
356 authctxt->postponed = 0;
357 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
358 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
359 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
360 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
361 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
364 Authmethod method_gsskeyex = {
367 &options.gss_authentication
370 Authmethod method_gssapi = {
373 &options.gss_authentication