1 /* $OpenBSD: auth2-gss.c,v 1.21 2014/02/26 20:28:44 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};
70 if (!authctxt->valid || authctxt->user == NULL)
73 mechs = packet_get_int();
75 debug("Mechanism negotiation is not supported");
85 doid = packet_get_string(&len);
87 if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
89 goid.elements = doid + 2;
90 goid.length = len - 2;
91 ssh_gssapi_test_oid_supported(&ms, &goid, &present);
93 logit("Badly formed OID received");
95 } while (mechs > 0 && !present);
99 authctxt->server_caused_failure = 1;
103 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
105 ssh_gssapi_delete_ctx(&ctxt);
107 authctxt->server_caused_failure = 1;
111 authctxt->methoddata = (void *)ctxt;
113 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
115 /* Return the OID that we received */
116 packet_put_string(doid, len);
121 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
122 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
123 authctxt->postponed = 1;
129 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
131 Authctxt *authctxt = ctxt;
133 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
134 gss_buffer_desc recv_tok;
135 OM_uint32 maj_status, min_status, flags;
138 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
139 fatal("No authentication or GSSAPI context");
141 gssctxt = authctxt->methoddata;
142 recv_tok.value = packet_get_string(&len);
143 recv_tok.length = len; /* u_int vs. size_t */
147 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
150 free(recv_tok.value);
152 if (GSS_ERROR(maj_status)) {
153 if (send_tok.length != 0) {
154 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
155 packet_put_string(send_tok.value, send_tok.length);
158 authctxt->postponed = 0;
159 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
160 userauth_finish(authctxt, 0, "gssapi-with-mic", NULL);
162 if (send_tok.length != 0) {
163 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
164 packet_put_string(send_tok.value, send_tok.length);
167 if (maj_status == GSS_S_COMPLETE) {
168 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
169 if (flags & GSS_C_INTEG_FLAG)
170 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
174 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
175 &input_gssapi_exchange_complete);
179 gss_release_buffer(&min_status, &send_tok);
183 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
185 Authctxt *authctxt = ctxt;
187 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
188 gss_buffer_desc recv_tok;
189 OM_uint32 maj_status;
192 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
193 fatal("No authentication or GSSAPI context");
195 gssctxt = authctxt->methoddata;
196 recv_tok.value = packet_get_string(&len);
197 recv_tok.length = len;
201 /* Push the error token into GSSAPI to see what it says */
202 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
205 free(recv_tok.value);
207 /* We can't return anything to the client, even if we wanted to */
208 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
209 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
211 /* The client will have already moved on to the next auth */
213 gss_release_buffer(&maj_status, &send_tok);
217 * This is called when the client thinks we've completed authentication.
218 * It should only be enabled in the dispatch handler by the function above,
219 * which only enables it once the GSSAPI exchange is complete.
223 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
225 Authctxt *authctxt = ctxt;
228 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
229 fatal("No authentication or GSSAPI context");
232 * We don't need to check the status, because we're only enabled in
233 * the dispatcher once the exchange is complete
238 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
240 authctxt->postponed = 0;
241 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
242 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
243 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
244 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
245 userauth_finish(authctxt, authenticated, "gssapi-with-mic", NULL);
249 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
251 Authctxt *authctxt = ctxt;
253 int authenticated = 0;
255 gss_buffer_desc mic, gssbuf;
258 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
259 fatal("No authentication or GSSAPI context");
261 gssctxt = authctxt->methoddata;
263 mic.value = packet_get_string(&len);
266 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
269 gssbuf.value = buffer_ptr(&b);
270 gssbuf.length = buffer_len(&b);
272 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
273 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
275 logit("GSSAPI MIC check failed");
280 authctxt->postponed = 0;
281 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
282 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
283 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
284 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
285 userauth_finish(authctxt, authenticated, "gssapi-with-mic", NULL);
288 Authmethod method_gssapi = {
291 &options.gss_authentication