1 /* $OpenBSD: auth2-gss.c,v 1.20 2013/05/17 00:13:13 djm 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 * We only support those mechanisms that we know about (ie ones that we know
57 * how to check local user kuserok and the like)
60 userauth_gssapi(Authctxt *authctxt)
62 gss_OID_desc goid = {0, NULL};
65 gss_OID_set supported;
71 if (!authctxt->valid || authctxt->user == NULL)
74 mechs = packet_get_int();
76 debug("Mechanism negotiation is not supported");
80 ssh_gssapi_supported_oids(&supported);
87 doid = packet_get_string(&len);
89 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
91 goid.elements = doid + 2;
92 goid.length = len - 2;
93 gss_test_oid_set_member(&ms, &goid, supported,
96 logit("Badly formed OID received");
98 } while (mechs > 0 && !present);
100 gss_release_oid_set(&ms, &supported);
104 authctxt->server_caused_failure = 1;
108 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
110 ssh_gssapi_delete_ctx(&ctxt);
112 authctxt->server_caused_failure = 1;
116 authctxt->methoddata = (void *)ctxt;
118 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
120 /* Return the OID that we received */
121 packet_put_string(doid, len);
126 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
127 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
128 authctxt->postponed = 1;
134 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
136 Authctxt *authctxt = ctxt;
138 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
139 gss_buffer_desc recv_tok;
140 OM_uint32 maj_status, min_status, flags;
143 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
144 fatal("No authentication or GSSAPI context");
146 gssctxt = authctxt->methoddata;
147 recv_tok.value = packet_get_string(&len);
148 recv_tok.length = len; /* u_int vs. size_t */
152 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
155 free(recv_tok.value);
157 if (GSS_ERROR(maj_status)) {
158 if (send_tok.length != 0) {
159 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
160 packet_put_string(send_tok.value, send_tok.length);
163 authctxt->postponed = 0;
164 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
165 userauth_finish(authctxt, 0, "gssapi-with-mic", NULL);
167 if (send_tok.length != 0) {
168 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
169 packet_put_string(send_tok.value, send_tok.length);
172 if (maj_status == GSS_S_COMPLETE) {
173 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
174 if (flags & GSS_C_INTEG_FLAG)
175 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
179 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
180 &input_gssapi_exchange_complete);
184 gss_release_buffer(&min_status, &send_tok);
188 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
190 Authctxt *authctxt = ctxt;
192 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
193 gss_buffer_desc recv_tok;
194 OM_uint32 maj_status;
197 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
198 fatal("No authentication or GSSAPI context");
200 gssctxt = authctxt->methoddata;
201 recv_tok.value = packet_get_string(&len);
202 recv_tok.length = len;
206 /* Push the error token into GSSAPI to see what it says */
207 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
210 free(recv_tok.value);
212 /* We can't return anything to the client, even if we wanted to */
213 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
214 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
216 /* The client will have already moved on to the next auth */
218 gss_release_buffer(&maj_status, &send_tok);
222 * This is called when the client thinks we've completed authentication.
223 * It should only be enabled in the dispatch handler by the function above,
224 * which only enables it once the GSSAPI exchange is complete.
228 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
230 Authctxt *authctxt = ctxt;
233 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
234 fatal("No authentication or GSSAPI context");
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", NULL);
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", NULL);
293 Authmethod method_gssapi = {
296 &options.gss_authentication