1 /* $OpenBSD: auth2-gss.c,v 1.3 2003/09/01 20:44:54 markus 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;
46 userauth_external(Authctxt *authctxt)
50 return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
53 static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
54 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
55 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
56 static void input_gssapi_errtok(int, u_int32_t, void *);
59 * We only support those mechanisms that we know about (ie ones that we know
60 * how to check local user kuserok and the like
63 userauth_gssapi(Authctxt *authctxt)
65 gss_OID_desc oid = {0, NULL};
68 gss_OID_set supported;
74 if (!authctxt->valid || authctxt->user == NULL)
77 mechs = packet_get_int();
79 debug("Mechanism negotiation is not supported");
83 ssh_gssapi_supported_oids(&supported);
90 doid = packet_get_string(&len);
92 if (doid[0] != SSH_GSS_OIDTYPE || doid[1] != len-2) {
93 logit("Mechanism OID received using the old encoding form");
97 oid.elements = doid + 2;
100 gss_test_oid_set_member(&ms, &oid, supported, &present);
101 } while (mechs > 0 && !present);
103 gss_release_oid_set(&ms, &supported);
110 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &oid)))) {
115 authctxt->methoddata=(void *)ctxt;
117 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
119 /* Return OID in same format as we received it*/
120 packet_put_string(doid, len);
125 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
126 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
127 authctxt->postponed = 1;
133 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
135 Authctxt *authctxt = ctxt;
137 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
138 gss_buffer_desc recv_tok;
139 OM_uint32 maj_status, min_status;
142 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
143 fatal("No authentication or GSSAPI context");
145 gssctxt = authctxt->methoddata;
146 recv_tok.value = packet_get_string(&len);
147 recv_tok.length = len; /* u_int vs. size_t */
151 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
154 xfree(recv_tok.value);
156 if (GSS_ERROR(maj_status)) {
157 ssh_gssapi_userauth_error(gssctxt);
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");
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 dispatch_set(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 xfree(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;
229 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
230 fatal("No authentication or GSSAPI context");
232 if ((strcmp(authctxt->user, "") == 0) && (authctxt->pw == NULL)) {
234 PRIVSEP(ssh_gssapi_localname(&lname));
235 if (lname && lname[0] != '\0') {
236 xfree(authctxt->user);
237 authctxt->user = lname;
238 debug("set username to %s from gssapi context", lname);
239 authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
241 debug("failed to set username from gssapi context");
246 PRIVSEP(start_pam(authctxt->pw->pw_name));
254 gssctxt = authctxt->methoddata;
257 * We don't need to check the status, because the stored credentials
258 * which userok uses are only populated once the context init step
259 * has returned complete.
264 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
267 authctxt->postponed = 0;
268 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
269 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
270 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
271 userauth_finish(authctxt, authenticated, "gssapi");
274 static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
278 errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
280 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
283 packet_put_cstring(errstr);
284 packet_put_cstring("");
291 Authmethod method_external = {
294 &options.gss_authentication
297 Authmethod method_gssapi = {
300 &options.gss_authentication