2 * Copyright (c) 2000 Markus Friedl. 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.
26 RCSID("$OpenBSD: auth2.c,v 1.100 2003/08/22 10:56:08 markus Exp $");
36 #include "pathnames.h"
37 #include "monitor_wrap.h"
44 extern ServerOptions options;
45 extern u_char *session_id2;
46 extern u_int session_id2_len;
48 Authctxt *x_authctxt = NULL;
52 extern Authmethod method_none;
53 extern Authmethod method_pubkey;
54 extern Authmethod method_passwd;
55 extern Authmethod method_kbdint;
56 extern Authmethod method_hostbased;
58 extern Authmethod method_kerberos;
61 extern Authmethod method_gssapi;
64 Authmethod *authmethods[] = {
81 static void input_service_request(int, u_int32_t, void *);
82 static void input_userauth_request(int, u_int32_t, void *);
85 static Authmethod *authmethod_lookup(const char *);
86 static char *authmethods_get(void);
87 int user_key_allowed(struct passwd *, Key *);
88 int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
91 * loop until authctxt->success == TRUE
95 do_authentication2(void)
97 Authctxt *authctxt = authctxt_new();
99 x_authctxt = authctxt; /*XXX*/
101 /* challenge-response is implemented via keyboard interactive */
102 if (options.challenge_response_authentication)
103 options.kbd_interactive_authentication = 1;
105 dispatch_init(&dispatch_protocol_error);
106 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
107 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
113 input_service_request(int type, u_int32_t seq, void *ctxt)
115 Authctxt *authctxt = ctxt;
118 char *service = packet_get_string(&len);
121 if (authctxt == NULL)
122 fatal("input_service_request: no authctxt");
124 if (strcmp(service, "ssh-userauth") == 0) {
125 if (!authctxt->success) {
127 /* now we can handle user-auth requests */
128 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
131 /* XXX all other service requests are denied */
134 packet_start(SSH2_MSG_SERVICE_ACCEPT);
135 packet_put_cstring(service);
139 debug("bad service request %s", service);
140 packet_disconnect("bad service request %s", service);
146 input_userauth_request(int type, u_int32_t seq, void *ctxt)
148 Authctxt *authctxt = ctxt;
149 Authmethod *m = NULL;
150 char *user, *service, *method, *style = NULL;
151 int authenticated = 0;
153 if (authctxt == NULL)
154 fatal("input_userauth_request: no authctxt");
156 user = packet_get_string(NULL);
157 service = packet_get_string(NULL);
158 method = packet_get_string(NULL);
159 debug("userauth-request for user %s service %s method %s", user, service, method);
160 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
162 if ((style = strchr(user, ':')) != NULL)
165 if (authctxt->attempt++ == 0) {
166 /* setup auth context */
167 authctxt->pw = PRIVSEP(getpwnamallow(user));
168 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
170 debug2("input_userauth_request: setting up authctxt for %s", user);
173 PRIVSEP(start_pam(authctxt->pw->pw_name));
176 logit("input_userauth_request: illegal user %s", user);
179 PRIVSEP(start_pam(user));
182 setproctitle("%s%s", authctxt->pw ? user : "unknown",
183 use_privsep ? " [net]" : "");
184 authctxt->user = xstrdup(user);
185 authctxt->service = xstrdup(service);
186 authctxt->style = style ? xstrdup(style) : NULL;
188 mm_inform_authserv(service, style);
189 } else if (strcmp(user, authctxt->user) != 0 ||
190 strcmp(service, authctxt->service) != 0) {
191 packet_disconnect("Change of username or service not allowed: "
192 "(%s,%s) -> (%s,%s)",
193 authctxt->user, authctxt->service, user, service);
196 auth2_challenge_stop(authctxt);
199 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
200 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
203 authctxt->postponed = 0;
205 /* try to authenticate user */
206 m = authmethod_lookup(method);
208 debug2("input_userauth_request: try method %s", method);
209 authenticated = m->userauth(authctxt);
211 userauth_finish(authctxt, authenticated, method);
219 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
223 if (!authctxt->valid && authenticated)
224 fatal("INTERNAL ERROR: authenticated invalid user %s",
227 /* Special handling for root */
228 if (authenticated && authctxt->pw->pw_uid == 0 &&
229 !auth_root_allowed(method))
233 if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
238 if (authenticated && cray_access_denied(authctxt->user)) {
240 fatal("Access denied for user %s.",authctxt->user);
244 /* Log before sending the reply */
245 auth_log(authctxt, authenticated, method, " ssh2");
247 if (authctxt->postponed)
250 /* XXX todo: check if multiple auth methods are needed */
251 if (authenticated == 1) {
252 /* turn off userauth */
253 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
254 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
257 /* now we can break out */
258 authctxt->success = 1;
260 if (authctxt->failures++ > AUTH_FAIL_MAX)
261 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
262 methods = authmethods_get();
263 packet_start(SSH2_MSG_USERAUTH_FAILURE);
264 packet_put_cstring(methods);
265 packet_put_char(0); /* XXX partial success, unused */
272 /* get current user */
277 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
283 authmethods_get(void)
290 for (i = 0; authmethods[i] != NULL; i++) {
291 if (strcmp(authmethods[i]->name, "none") == 0)
293 if (authmethods[i]->enabled != NULL &&
294 *(authmethods[i]->enabled) != 0) {
295 if (buffer_len(&b) > 0)
296 buffer_append(&b, ",", 1);
297 buffer_append(&b, authmethods[i]->name,
298 strlen(authmethods[i]->name));
301 buffer_append(&b, "\0", 1);
302 list = xstrdup(buffer_ptr(&b));
308 authmethod_lookup(const char *name)
313 for (i = 0; authmethods[i] != NULL; i++)
314 if (authmethods[i]->enabled != NULL &&
315 *(authmethods[i]->enabled) != 0 &&
316 strcmp(name, authmethods[i]->name) == 0)
317 return authmethods[i];
318 debug2("Unrecognized authentication method name: %s",
319 name ? name : "NULL");