1 /* $OpenBSD: auth2-gss.c,v 1.8 2004/06/21 17:36:31 avsm 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.
39 #include "monitor_wrap.h"
43 extern ServerOptions options;
45 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
46 static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
47 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
48 static void input_gssapi_errtok(int, u_int32_t, void *);
51 * We only support those mechanisms that we know about (ie ones that we know
52 * how to check local user kuserok and the like
55 userauth_gssapi(Authctxt *authctxt)
57 gss_OID_desc goid = {0, NULL};
60 gss_OID_set supported;
66 if (!authctxt->valid || authctxt->user == NULL)
69 mechs = packet_get_int();
71 debug("Mechanism negotiation is not supported");
75 ssh_gssapi_supported_oids(&supported);
83 doid = packet_get_string(&len);
86 doid[0] == SSH_GSS_OIDTYPE &&
88 goid.elements = doid + 2;
89 goid.length = len - 2;
90 gss_test_oid_set_member(&ms, &goid, supported,
93 logit("Badly formed OID received");
95 } while (mechs > 0 && !present);
97 gss_release_oid_set(&ms, &supported);
104 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
109 authctxt->methoddata=(void *)ctxt;
111 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
113 /* Return the OID that we received */
114 packet_put_string(doid, len);
119 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
120 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
121 authctxt->postponed = 1;
127 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
129 Authctxt *authctxt = ctxt;
131 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
132 gss_buffer_desc recv_tok;
133 OM_uint32 maj_status, min_status, flags;
136 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
137 fatal("No authentication or GSSAPI context");
139 gssctxt = authctxt->methoddata;
140 recv_tok.value = packet_get_string(&len);
141 recv_tok.length = len; /* u_int vs. size_t */
145 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
148 xfree(recv_tok.value);
150 if (GSS_ERROR(maj_status)) {
151 if (send_tok.length != 0) {
152 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
153 packet_put_string(send_tok.value, send_tok.length);
156 authctxt->postponed = 0;
157 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
158 userauth_finish(authctxt, 0, "gssapi-with-mic");
160 if (send_tok.length != 0) {
161 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
162 packet_put_string(send_tok.value, send_tok.length);
165 if (maj_status == GSS_S_COMPLETE) {
166 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
167 if (flags & GSS_C_INTEG_FLAG)
168 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
172 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
173 &input_gssapi_exchange_complete);
177 gss_release_buffer(&min_status, &send_tok);
181 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
183 Authctxt *authctxt = ctxt;
185 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
186 gss_buffer_desc recv_tok;
187 OM_uint32 maj_status;
190 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
191 fatal("No authentication or GSSAPI context");
193 gssctxt = authctxt->methoddata;
194 recv_tok.value = packet_get_string(&len);
195 recv_tok.length = len;
199 /* Push the error token into GSSAPI to see what it says */
200 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
203 xfree(recv_tok.value);
205 /* We can't return anything to the client, even if we wanted to */
206 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
207 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
209 /* The client will have already moved on to the next auth */
211 gss_release_buffer(&maj_status, &send_tok);
215 * This is called when the client thinks we've completed authentication.
216 * It should only be enabled in the dispatch handler by the function above,
217 * which only enables it once the GSSAPI exchange is complete.
221 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
223 Authctxt *authctxt = ctxt;
227 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
228 fatal("No authentication or GSSAPI context");
230 gssctxt = authctxt->methoddata;
233 * We don't need to check the status, because we're only enabled in
234 * the dispatcher once the exchange is complete
239 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
241 authctxt->postponed = 0;
242 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
243 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
244 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
245 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
246 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
250 input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
252 Authctxt *authctxt = ctxt;
254 int authenticated = 0;
256 gss_buffer_desc mic, gssbuf;
259 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
260 fatal("No authentication or GSSAPI context");
262 gssctxt = authctxt->methoddata;
264 mic.value = packet_get_string(&len);
267 ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
270 gssbuf.value = buffer_ptr(&b);
271 gssbuf.length = buffer_len(&b);
273 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
274 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
276 logit("GSSAPI MIC check failed");
281 authctxt->postponed = 0;
282 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
283 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
284 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
285 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
286 userauth_finish(authctxt, authenticated, "gssapi-with-mic");
289 Authmethod method_gssapi = {
292 &options.gss_authentication