2 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 #include "monitor_wrap.h"
41 extern ServerOptions options;
42 unsigned char ssh1_key_digest[16];
45 userauth_external(Authctxt *authctxt)
49 return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
52 static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
53 static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
54 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
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 oid= {0,NULL};
65 gss_OID_set supported;
71 if (!authctxt->valid || authctxt->user == NULL)
74 if (datafellows & SSH_OLD_GSSAPI) {
75 debug("Early drafts of GSSAPI userauth not supported");
79 mechs=packet_get_int();
81 debug("Mechanism negotiation is not supported");
85 ssh_gssapi_supported_oids(&supported);
92 debug("Trying to get OID string");
93 doid = packet_get_string(&len);
96 if (datafellows & SSH_BUG_GSSAPI_BER) {
100 if (doid[0]!=0x06 || doid[1]!=len-2) {
101 debug("Badly encoded mechanism OID received");
104 oid.elements = doid + 2;
105 oid.length = len - 2;
106 gss_test_oid_set_member(&ms, &oid, supported, &present);
110 gss_test_oid_set_member(&ms, &oid, supported, &present);
112 } while (mechs>0 && !present);
119 if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt,&oid)))) {
120 ssh_gssapi_userauth_error(ctxt);
124 authctxt->methoddata=(void *)ctxt;
126 /* Send SSH_MSG_USERAUTH_GSSAPI_RESPONSE */
130 packet_start(SSH_SMSG_AUTH_GSSAPI_RESPONSE);
131 packet_put_string(oid.elements,oid.length);
135 packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
137 if (datafellows & SSH_BUG_GSSAPI_BER) {
138 packet_put_string(oid.elements,oid.length);
140 packet_put_string(doid,len);
150 dispatch_set(SSH_MSG_AUTH_GSSAPI_TOKEN,
151 &input_gssapi_token);
153 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,
154 &input_gssapi_token);
155 authctxt->postponed = 1;
161 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
163 Authctxt *authctxt = ctxt;
165 gss_buffer_desc send_tok,recv_tok;
166 OM_uint32 maj_status, min_status;
169 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
170 fatal("No authentication or GSSAPI context");
172 gssctxt=authctxt->methoddata;
173 recv_tok.value=packet_get_string(&len);
174 recv_tok.length=len; /* int vs. size_t */
176 maj_status=PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
180 if (send_tok.length != 0) {
181 /* Send a packet back to the client, even if there has
182 * been an error, as this may contain mechanism specific
183 * error information */
185 packet_start(SSH_MSG_AUTH_GSSAPI_TOKEN);
187 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
188 packet_put_string(send_tok.value,send_tok.length);
191 gss_release_buffer(&min_status, &send_tok);
194 if (GSS_ERROR(maj_status)) {
195 ssh_gssapi_userauth_error(gssctxt);
196 authctxt->postponed = 0;
197 dispatch_set(SSH_MSG_AUTH_GSSAPI_TOKEN, NULL);
198 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
199 userauth_finish(authctxt, 0, "gssapi");
202 if (maj_status == GSS_S_COMPLETE) {
203 dispatch_set(SSH_MSG_AUTH_GSSAPI_TOKEN, NULL);
204 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,NULL);
205 /* ssh1 does not have an extra message here */
207 input_gssapi_exchange_complete(0, 0, ctxt);
209 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
210 &input_gssapi_exchange_complete);
214 /* This is called when the client thinks we've completed authentication.
215 * It should only be enabled in the dispatch handler by the function above,
216 * which only enables it once the GSSAPI exchange is complete.
220 input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
222 Authctxt *authctxt = ctxt;
226 if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
227 fatal("No authentication or GSSAPI context");
229 if ((strcmp(authctxt->user, "") == 0) && (authctxt->pw == NULL)) {
231 PRIVSEP(ssh_gssapi_localname(&lname));
232 if (lname && lname[0] != '\0') {
233 xfree(authctxt->user);
234 authctxt->user = lname;
235 debug("set username to %s from gssapi context", lname);
236 authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
238 debug("failed to set username from gssapi context");
243 PRIVSEP(start_pam(authctxt->pw->pw_name));
251 gssctxt=authctxt->methoddata;
253 /* ssh1 needs to exchange the hash of the keys */
256 OM_uint32 min_status;
257 gss_buffer_desc dummy, msg_tok;
259 /* ssh1 wraps the keys, in the monitor */
261 dummy.value=malloc(sizeof(ssh1_key_digest));
262 memcpy(dummy.value,ssh1_key_digest,sizeof(ssh1_key_digest));
263 dummy.length=sizeof(ssh1_key_digest);
264 if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(gssctxt,&dummy,&msg_tok))))
265 fatal("Couldn't wrap keys");
267 packet_start(SSH_SMSG_AUTH_GSSAPI_HASH);
268 packet_put_string((char *)msg_tok.value,msg_tok.length);
271 gss_release_buffer(&min_status,&msg_tok);
275 /* We don't need to check the status, because the stored credentials
276 * which userok uses are only populated once the context init step
277 * has returned complete.
280 authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
283 authctxt->postponed = 0;
284 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
285 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
286 userauth_finish(authctxt, authenticated, "gssapi");
289 static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
293 errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
295 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
298 packet_put_cstring(errstr);
299 packet_put_cstring("");
306 Authmethod method_external = {
309 &options.gss_authentication
312 Authmethod method_gssapi = {
315 &options.gss_authentication