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>
44 #include "monitor_wrap.h"
46 extern ServerOptions options;
48 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
49 static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
50 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
51 static void input_gssapi_errtok(int, u_int32_t, void *);
54 * We only support those mechanisms that we know about (ie ones that we know
55 * how to check local user kuserok and the like)
58 userauth_gssapi(Authctxt *authctxt)
60 gss_OID_desc goid = {0, NULL};
63 gss_OID_set supported;
69 if (!authctxt->valid || authctxt->user == NULL)
72 mechs = packet_get_int();
74 debug("Mechanism negotiation is not supported");
78 ssh_gssapi_supported_oids(&supported);
86 doid = packet_get_string(&len);
88 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
90 goid.elements = doid + 2;
91 goid.length = len - 2;
92 gss_test_oid_set_member(&ms, &goid, supported,
95 logit("Badly formed OID received");
97 } while (mechs > 0 && !present);
99 gss_release_oid_set(&ms, &supported);
106 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
108 ssh_gssapi_delete_ctx(&ctxt);
113 authctxt->methoddata = (void *)ctxt;
115 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
117 /* Return the OID that we received */
118 packet_put_string(doid, len);
123 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
124 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
125 authctxt->postponed = 1;
131 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
133 Authctxt *authctxt = ctxt;
135 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
136 gss_buffer_desc recv_tok;
137 OM_uint32 maj_status, min_status, flags;
140 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
141 fatal("No authentication or GSSAPI context");
143 gssctxt = authctxt->methoddata;
144 recv_tok.value = packet_get_string(&len);
145 recv_tok.length = len; /* u_int vs. size_t */
149 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
152 xfree(recv_tok.value);
154 if (GSS_ERROR(maj_status)) {
155 if (send_tok.length != 0) {
156 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
157 packet_put_string(send_tok.value, send_tok.length);
160 authctxt->postponed = 0;
161 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
162 userauth_finish(authctxt, 0, "gssapi-with-mic");
164 if (send_tok.length != 0) {
165 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
166 packet_put_string(send_tok.value, send_tok.length);
169 if (maj_status == GSS_S_COMPLETE) {
170 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
171 if (flags & GSS_C_INTEG_FLAG)
172 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
176 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
177 &input_gssapi_exchange_complete);
181 gss_release_buffer(&min_status, &send_tok);
185 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
187 Authctxt *authctxt = ctxt;
189 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
190 gss_buffer_desc recv_tok;
191 OM_uint32 maj_status;
194 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
195 fatal("No authentication or GSSAPI context");
197 gssctxt = authctxt->methoddata;
198 recv_tok.value = packet_get_string(&len);
199 recv_tok.length = len;
203 /* Push the error token into GSSAPI to see what it says */
204 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
207 xfree(recv_tok.value);
209 /* We can't return anything to the client, even if we wanted to */
210 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
211 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
213 /* The client will have already moved on to the next auth */
215 gss_release_buffer(&maj_status, &send_tok);
219 * This is called when the client thinks we've completed authentication.
220 * It should only be enabled in the dispatch handler by the function above,
221 * which only enables it once the GSSAPI exchange is complete.
225 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
227 Authctxt *authctxt = ctxt;
231 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
232 fatal("No authentication or GSSAPI context");
234 gssctxt = authctxt->methoddata;
237 * We don't need to check the status, because we're only enabled in
238 * the dispatcher once the exchange is complete
243 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
245 authctxt->postponed = 0;
246 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
247 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
248 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
249 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
250 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
254 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
256 Authctxt *authctxt = ctxt;
258 int authenticated = 0;
260 gss_buffer_desc mic, gssbuf;
263 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
264 fatal("No authentication or GSSAPI context");
266 gssctxt = authctxt->methoddata;
268 mic.value = packet_get_string(&len);
271 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
274 gssbuf.value = buffer_ptr(&b);
275 gssbuf.length = buffer_len(&b);
277 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
278 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
280 logit("GSSAPI MIC check failed");
285 authctxt->postponed = 0;
286 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
287 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
288 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
289 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
290 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
293 Authmethod method_gssapi = {
296 &options.gss_authentication