1 /* $OpenBSD: auth2.c,v 1.113 2006/08/03 03:34:41 deraadt Exp $ */
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include <sys/types.h>
45 #include "pathnames.h"
51 #include "monitor_wrap.h"
54 extern ServerOptions options;
55 extern u_char *session_id2;
56 extern u_int session_id2_len;
57 extern Buffer loginmsg;
61 extern Authmethod method_none;
62 extern Authmethod method_pubkey;
63 extern Authmethod method_passwd;
64 extern Authmethod method_kbdint;
65 extern Authmethod method_hostbased;
67 extern Authmethod method_gsskeyex;
68 extern Authmethod method_gssapi;
71 Authmethod *authmethods[] = {
86 static void input_service_request(int, u_int32_t, void *);
87 static void input_userauth_request(int, u_int32_t, void *);
90 static Authmethod *authmethod_lookup(const char *);
91 static char *authmethods_get(void);
92 int user_key_allowed(struct passwd *, Key *);
95 * loop until authctxt->success == TRUE
99 do_authentication2(Authctxt *authctxt)
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);
112 input_service_request(int type, u_int32_t seq, void *ctxt)
114 Authctxt *authctxt = ctxt;
117 char *service = packet_get_string(&len);
120 if (authctxt == NULL)
121 fatal("input_service_request: no authctxt");
123 if (strcmp(service, "ssh-userauth") == 0) {
124 if (!authctxt->success) {
126 /* now we can handle user-auth requests */
127 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
130 /* XXX all other service requests are denied */
133 packet_start(SSH2_MSG_SERVICE_ACCEPT);
134 packet_put_cstring(service);
138 debug("bad service request %s", service);
139 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 authctxt->user = xstrdup(user);
169 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
171 debug2("input_userauth_request: setting up authctxt for %s", user);
173 logit("input_userauth_request: invalid user %s", user);
174 authctxt->pw = fakepw();
175 #ifdef SSH_AUDIT_EVENTS
176 PRIVSEP(audit_event(SSH_INVALID_USER));
181 PRIVSEP(start_pam(authctxt));
183 setproctitle("%s%s", authctxt->valid ? user : "unknown",
184 use_privsep ? " [net]" : "");
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;
204 authctxt->server_caused_failure = 0;
206 /* try to authenticate user */
207 m = authmethod_lookup(method);
209 debug2("input_userauth_request: try method %s", method);
210 authenticated = m->userauth(authctxt);
212 userauth_finish(authctxt, authenticated, method);
220 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
224 if (!authctxt->valid && authenticated)
225 fatal("INTERNAL ERROR: authenticated invalid user %s",
228 /* Special handling for root */
229 if (authenticated && authctxt->pw->pw_uid == 0 &&
230 !auth_root_allowed(method)) {
232 #ifdef SSH_AUDIT_EVENTS
233 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
238 if (options.use_pam && authenticated) {
239 if (!PRIVSEP(do_pam_account())) {
240 /* if PAM returned a message, send it to the user */
241 if (buffer_len(&loginmsg) > 0) {
242 buffer_append(&loginmsg, "\0", 1);
243 userauth_send_banner(buffer_ptr(&loginmsg));
246 fatal("Access denied for user %s by PAM account "
247 "configuration", authctxt->user);
253 if (authenticated && cray_access_denied(authctxt->user)) {
255 fatal("Access denied for user %s.",authctxt->user);
259 /* Log before sending the reply */
260 auth_log(authctxt, authenticated, method, " ssh2");
262 if (authctxt->postponed)
265 /* XXX todo: check if multiple auth methods are needed */
266 if (authenticated == 1) {
267 /* turn off userauth */
268 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
269 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
272 /* now we can break out */
273 authctxt->success = 1;
275 /* Dont count server configuration issues against the client */
276 if (!authctxt->server_caused_failure &&
277 authctxt->failures++ > options.max_authtries) {
278 #ifdef SSH_AUDIT_EVENTS
279 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
281 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
283 methods = authmethods_get();
284 packet_start(SSH2_MSG_USERAUTH_FAILURE);
285 packet_put_cstring(methods);
286 packet_put_char(0); /* XXX partial success, unused */
296 authmethods_get(void)
303 for (i = 0; authmethods[i] != NULL; i++) {
304 if (strcmp(authmethods[i]->name, "none") == 0)
306 if (authmethods[i]->enabled != NULL &&
307 *(authmethods[i]->enabled) != 0) {
308 if (buffer_len(&b) > 0)
309 buffer_append(&b, ",", 1);
310 buffer_append(&b, authmethods[i]->name,
311 strlen(authmethods[i]->name));
314 buffer_append(&b, "\0", 1);
315 list = xstrdup(buffer_ptr(&b));
321 authmethod_lookup(const char *name)
326 for (i = 0; authmethods[i] != NULL; i++)
327 if (authmethods[i]->enabled != NULL &&
328 *(authmethods[i]->enabled) != 0 &&
329 strcmp(name, authmethods[i]->name) == 0)
330 return authmethods[i];
331 debug2("Unrecognized authentication method name: %s",
332 name ? name : "NULL");