1 /* $OpenBSD: auth2-gss.c,v 1.12 2005/10/13 22:24:31 stevesk 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.
38 #include "monitor_wrap.h"
42 extern ServerOptions options;
44 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
45 static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
46 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
47 static void input_gssapi_errtok(int, u_int32_t, void *);
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)
54 userauth_gssapi(Authctxt *authctxt)
56 gss_OID_desc goid = {0, NULL};
59 gss_OID_set supported;
65 if (!authctxt->valid || authctxt->user == NULL)
68 mechs = packet_get_int();
70 debug("Mechanism negotiation is not supported");
74 ssh_gssapi_supported_oids(&supported);
82 doid = packet_get_string(&len);
84 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
86 goid.elements = doid + 2;
87 goid.length = len - 2;
88 gss_test_oid_set_member(&ms, &goid, supported,
91 logit("Badly formed OID received");
93 } while (mechs > 0 && !present);
95 gss_release_oid_set(&ms, &supported);
102 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
107 authctxt->methoddata = (void *)ctxt;
109 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
111 /* Return the OID that we received */
112 packet_put_string(doid, len);
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;
125 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
127 Authctxt *authctxt = ctxt;
129 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
130 gss_buffer_desc recv_tok;
131 OM_uint32 maj_status, min_status, flags;
134 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
135 fatal("No authentication or GSSAPI context");
137 gssctxt = authctxt->methoddata;
138 recv_tok.value = packet_get_string(&len);
139 recv_tok.length = len; /* u_int vs. size_t */
143 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
146 xfree(recv_tok.value);
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);
154 authctxt->postponed = 0;
155 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
156 userauth_finish(authctxt, 0, "gssapi-with-mic");
158 if (send_tok.length != 0) {
159 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
160 packet_put_string(send_tok.value, send_tok.length);
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,
170 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
171 &input_gssapi_exchange_complete);
175 gss_release_buffer(&min_status, &send_tok);
179 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
181 Authctxt *authctxt = ctxt;
183 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
184 gss_buffer_desc recv_tok;
185 OM_uint32 maj_status;
188 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
189 fatal("No authentication or GSSAPI context");
191 gssctxt = authctxt->methoddata;
192 recv_tok.value = packet_get_string(&len);
193 recv_tok.length = len;
197 /* Push the error token into GSSAPI to see what it says */
198 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
201 xfree(recv_tok.value);
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);
207 /* The client will have already moved on to the next auth */
209 gss_release_buffer(&maj_status, &send_tok);
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.
219 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
221 Authctxt *authctxt = ctxt;
225 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
226 fatal("No authentication or GSSAPI context");
228 gssctxt = authctxt->methoddata;
231 * We don't need to check the status, because we're only enabled in
232 * the dispatcher once the exchange is complete
237 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
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");
248 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
250 Authctxt *authctxt = ctxt;
252 int authenticated = 0;
254 gss_buffer_desc mic, gssbuf;
257 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
258 fatal("No authentication or GSSAPI context");
260 gssctxt = authctxt->methoddata;
262 mic.value = packet_get_string(&len);
265 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
268 gssbuf.value = buffer_ptr(&b);
269 gssbuf.length = buffer_len(&b);
271 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
272 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
274 logit("GSSAPI MIC check failed");
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");
287 Authmethod method_gssapi = {
290 &options.gss_authentication