1 /* $OpenBSD: auth2-gss.c,v 1.17 2011/03/10 02:52:57 djm 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 if (!authctxt->valid || authctxt->user == NULL)
108 mechs = packet_get_int();
110 debug("Mechanism negotiation is not supported");
114 ssh_gssapi_supported_oids(&supported);
122 doid = packet_get_string(&len);
124 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
125 doid[1] == len - 2) {
126 goid.elements = doid + 2;
127 goid.length = len - 2;
128 gss_test_oid_set_member(&ms, &goid, supported,
131 logit("Badly formed OID received");
133 } while (mechs > 0 && !present);
135 gss_release_oid_set(&ms, &supported);
139 authctxt->server_caused_failure = 1;
143 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
145 ssh_gssapi_delete_ctx(&ctxt);
147 authctxt->server_caused_failure = 1;
151 authctxt->methoddata = (void *)ctxt;
153 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
155 /* Return the OID that we received */
156 packet_put_string(doid, len);
161 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
162 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
163 authctxt->postponed = 1;
169 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
171 Authctxt *authctxt = ctxt;
173 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
174 gss_buffer_desc recv_tok;
175 OM_uint32 maj_status, min_status, flags;
178 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
179 fatal("No authentication or GSSAPI context");
181 gssctxt = authctxt->methoddata;
182 recv_tok.value = packet_get_string(&len);
183 recv_tok.length = len; /* u_int vs. size_t */
187 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
190 xfree(recv_tok.value);
192 if (GSS_ERROR(maj_status)) {
193 if (send_tok.length != 0) {
194 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
195 packet_put_string(send_tok.value, send_tok.length);
198 authctxt->postponed = 0;
199 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
200 userauth_finish(authctxt, 0, "gssapi-with-mic");
202 if (send_tok.length != 0) {
203 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
204 packet_put_string(send_tok.value, send_tok.length);
207 if (maj_status == GSS_S_COMPLETE) {
208 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
209 if (flags & GSS_C_INTEG_FLAG)
210 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
214 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
215 &input_gssapi_exchange_complete);
219 gss_release_buffer(&min_status, &send_tok);
223 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
225 Authctxt *authctxt = ctxt;
227 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
228 gss_buffer_desc recv_tok;
229 OM_uint32 maj_status;
232 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
233 fatal("No authentication or GSSAPI context");
235 gssctxt = authctxt->methoddata;
236 recv_tok.value = packet_get_string(&len);
237 recv_tok.length = len;
241 /* Push the error token into GSSAPI to see what it says */
242 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
245 xfree(recv_tok.value);
247 /* We can't return anything to the client, even if we wanted to */
248 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
249 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
251 /* The client will have already moved on to the next auth */
253 gss_release_buffer(&maj_status, &send_tok);
257 * This is called when the client thinks we've completed authentication.
258 * It should only be enabled in the dispatch handler by the function above,
259 * which only enables it once the GSSAPI exchange is complete.
263 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
265 Authctxt *authctxt = ctxt;
269 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
270 fatal("No authentication or GSSAPI context");
272 gssctxt = authctxt->methoddata;
275 * We don't need to check the status, because we're only enabled in
276 * the dispatcher once the exchange is complete
281 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
284 authctxt->postponed = 0;
285 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
286 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
287 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
288 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
289 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
293 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
295 Authctxt *authctxt = ctxt;
297 int authenticated = 0;
299 gss_buffer_desc mic, gssbuf;
302 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
303 fatal("No authentication or GSSAPI context");
305 gssctxt = authctxt->methoddata;
307 mic.value = packet_get_string(&len);
310 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
313 gssbuf.value = buffer_ptr(&b);
314 gssbuf.length = buffer_len(&b);
316 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
318 PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw));
320 logit("GSSAPI MIC check failed");
325 authctxt->postponed = 0;
326 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
327 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
328 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
329 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
330 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
333 Authmethod method_gsskeyex = {
336 &options.gss_authentication
339 Authmethod method_gssapi = {
342 &options.gss_authentication