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;
45 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
46 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
47 static void input_gssapi_errtok(int, u_int32_t, void *);
50 * We only support those mechanisms that we know about (ie ones that we know
51 * how to check local user kuserok and the like
54 userauth_gssapi(Authctxt *authctxt)
56 gss_OID_desc oid = {0, NULL};
59 gss_OID_set supported;
65 if (!authctxt->valid || authctxt->user == NULL)
68 mechs = packet_get_int();
70 debug("Mechanism negotiation is not supported");
74 ssh_gssapi_supported_oids(&supported);
81 doid = packet_get_string(&len);
83 if (doid[0] != SSH_GSS_OIDTYPE || doid[1] != len-2) {
84 logit("Mechanism OID received using the old encoding form");
88 oid.elements = doid + 2;
91 gss_test_oid_set_member(&ms, &oid, supported, &present);
92 } while (mechs > 0 && !present);
94 gss_release_oid_set(&ms, &supported);
101 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &oid)))) {
106 authctxt->methoddata=(void *)ctxt;
108 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
110 /* Return OID in same format as we received it*/
111 packet_put_string(doid, len);
116 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
117 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
118 authctxt->postponed = 1;
124 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
126 Authctxt *authctxt = ctxt;
128 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
129 gss_buffer_desc recv_tok;
130 OM_uint32 maj_status, min_status;
133 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
134 fatal("No authentication or GSSAPI context");
136 gssctxt = authctxt->methoddata;
137 recv_tok.value = packet_get_string(&len);
138 recv_tok.length = len; /* u_int vs. size_t */
142 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
145 xfree(recv_tok.value);
147 if (GSS_ERROR(maj_status)) {
148 if (send_tok.length != 0) {
149 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
150 packet_put_string(send_tok.value, send_tok.length);
153 authctxt->postponed = 0;
154 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
155 userauth_finish(authctxt, 0, "gssapi");
157 if (send_tok.length != 0) {
158 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
159 packet_put_string(send_tok.value, send_tok.length);
162 if (maj_status == GSS_S_COMPLETE) {
163 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
164 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
165 &input_gssapi_exchange_complete);
169 gss_release_buffer(&min_status, &send_tok);
173 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
175 Authctxt *authctxt = ctxt;
177 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
178 gss_buffer_desc recv_tok;
179 OM_uint32 maj_status;
182 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
183 fatal("No authentication or GSSAPI context");
185 gssctxt = authctxt->methoddata;
186 recv_tok.value = packet_get_string(&len);
187 recv_tok.length = len;
191 /* Push the error token into GSSAPI to see what it says */
192 maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
195 xfree(recv_tok.value);
197 /* We can't return anything to the client, even if we wanted to */
198 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
199 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
201 /* The client will have already moved on to the next auth */
203 gss_release_buffer(&maj_status, &send_tok);
207 * This is called when the client thinks we've completed authentication.
208 * It should only be enabled in the dispatch handler by the function above,
209 * which only enables it once the GSSAPI exchange is complete.
213 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
215 Authctxt *authctxt = ctxt;
219 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
220 fatal("No authentication or GSSAPI context");
222 gssctxt = authctxt->methoddata;
225 * We don't need to check the status, because the stored credentials
226 * which userok uses are only populated once the context init step
227 * has returned complete.
232 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
234 authctxt->postponed = 0;
235 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
236 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
237 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
238 userauth_finish(authctxt, authenticated, "gssapi");
241 Authmethod method_gssapi = {
244 &options.gss_authentication