1 /* $OpenBSD: auth2.c,v 1.120 2008/11/04 08:22:12 djm 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>
50 #include "pathnames.h"
57 #include "monitor_wrap.h"
60 extern ServerOptions options;
61 extern u_char *session_id2;
62 extern u_int session_id2_len;
63 extern Buffer loginmsg;
67 extern Authmethod method_none;
68 extern Authmethod method_pubkey;
69 extern Authmethod method_passwd;
70 extern Authmethod method_kbdint;
71 extern Authmethod method_hostbased;
73 extern Authmethod method_gsskeyex;
74 extern Authmethod method_gssapi;
77 extern Authmethod method_jpake;
80 static int log_flag = 0;
83 Authmethod *authmethods[] = {
101 static void input_service_request(int, u_int32_t, void *);
102 static void input_userauth_request(int, u_int32_t, void *);
105 static Authmethod *authmethod_lookup(const char *);
106 static char *authmethods_get(void);
109 auth2_read_banner(void)
116 if ((fd = open(options.banner, O_RDONLY)) == -1)
118 if (fstat(fd, &st) == -1) {
122 if (st.st_size > 1*1024*1024) {
127 len = (size_t)st.st_size; /* truncate */
128 banner = xmalloc(len + 1);
129 n = atomicio(read, fd, banner, len);
142 userauth_send_banner(const char *msg)
144 if (datafellows & SSH_BUG_BANNER)
147 packet_start(SSH2_MSG_USERAUTH_BANNER);
148 packet_put_cstring(msg);
149 packet_put_cstring(""); /* language, unused */
151 debug("%s: sent", __func__);
155 userauth_banner(void)
159 if (options.banner == NULL ||
160 strcasecmp(options.banner, "none") == 0 ||
161 (datafellows & SSH_BUG_BANNER) != 0)
164 if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
166 userauth_send_banner(banner);
174 * loop until authctxt->success == TRUE
177 do_authentication2(Authctxt *authctxt)
179 dispatch_init(&dispatch_protocol_error);
180 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
181 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
186 input_service_request(int type, u_int32_t seq, void *ctxt)
188 Authctxt *authctxt = ctxt;
191 char *service = packet_get_string(&len);
194 if (authctxt == NULL)
195 fatal("input_service_request: no authctxt");
197 if (strcmp(service, "ssh-userauth") == 0) {
198 if (!authctxt->success) {
200 /* now we can handle user-auth requests */
201 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
204 /* XXX all other service requests are denied */
207 packet_start(SSH2_MSG_SERVICE_ACCEPT);
208 packet_put_cstring(service);
212 debug("bad service request %s", service);
213 packet_disconnect("bad service request %s", service);
220 input_userauth_request(int type, u_int32_t seq, void *ctxt)
222 Authctxt *authctxt = ctxt;
223 Authmethod *m = NULL;
224 char *user, *service, *method, *style = NULL;
225 int authenticated = 0;
227 if (authctxt == NULL)
228 fatal("input_userauth_request: no authctxt");
230 user = packet_get_string(NULL);
231 service = packet_get_string(NULL);
232 method = packet_get_string(NULL);
233 debug("userauth-request for user %s service %s method %s", user, service, method);
235 logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s",
236 get_remote_ipaddr(), get_remote_port(), user);
239 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
241 if ((style = strchr(user, ':')) != NULL)
244 if (authctxt->attempt++ == 0) {
245 /* setup auth context */
246 authctxt->pw = PRIVSEP(getpwnamallow(user));
247 authctxt->user = xstrdup(user);
248 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
250 debug2("input_userauth_request: setting up authctxt for %s", user);
252 logit("input_userauth_request: invalid user %s", user);
253 authctxt->pw = fakepw();
254 #ifdef SSH_AUDIT_EVENTS
255 PRIVSEP(audit_event(SSH_INVALID_USER));
260 PRIVSEP(start_pam(authctxt));
262 setproctitle("%s%s", authctxt->valid ? user : "unknown",
263 use_privsep ? " [net]" : "");
264 authctxt->service = xstrdup(service);
265 authctxt->style = style ? xstrdup(style) : NULL;
267 mm_inform_authserv(service, style);
269 } else if (strcmp(user, authctxt->user) != 0 ||
270 strcmp(service, authctxt->service) != 0) {
271 packet_disconnect("Change of username or service not allowed: "
272 "(%s,%s) -> (%s,%s)",
273 authctxt->user, authctxt->service, user, service);
276 auth2_challenge_stop(authctxt);
278 auth2_jpake_stop(authctxt);
282 /* XXX move to auth2_gssapi_stop() */
283 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
284 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
287 authctxt->postponed = 0;
288 authctxt->server_caused_failure = 0;
290 /* try to authenticate user */
291 m = authmethod_lookup(method);
292 if (m != NULL && authctxt->failures < options.max_authtries) {
293 debug2("input_userauth_request: try method %s", method);
294 authenticated = m->userauth(authctxt);
296 userauth_finish(authctxt, authenticated, method);
304 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
308 if (!authctxt->valid && authenticated)
309 fatal("INTERNAL ERROR: authenticated invalid user %s",
312 /* Special handling for root */
313 if (authenticated && authctxt->pw->pw_uid == 0 &&
314 !auth_root_allowed(method)) {
316 #ifdef SSH_AUDIT_EVENTS
317 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
322 if (options.use_pam && authenticated) {
323 if (!PRIVSEP(do_pam_account())) {
324 /* if PAM returned a message, send it to the user */
325 if (buffer_len(&loginmsg) > 0) {
326 buffer_append(&loginmsg, "\0", 1);
327 userauth_send_banner(buffer_ptr(&loginmsg));
330 fatal("Access denied for user %s by PAM account "
331 "configuration", authctxt->user);
337 if (authenticated && cray_access_denied(authctxt->user)) {
339 fatal("Access denied for user %s.",authctxt->user);
343 /* Log before sending the reply */
344 auth_log(authctxt, authenticated, method, " ssh2");
346 if (authctxt->postponed)
349 /* XXX todo: check if multiple auth methods are needed */
350 if (authenticated == 1) {
351 /* turn off userauth */
352 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
353 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
356 /* now we can break out */
357 authctxt->success = 1;
360 /* Allow initial try of "none" auth without failure penalty */
361 if (!authctxt->server_caused_failure &&
362 (authctxt->attempt > 1 || strcmp(method, "none") != 0))
363 authctxt->failures++;
364 if (authctxt->failures >= options.max_authtries) {
365 #ifdef SSH_AUDIT_EVENTS
366 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
368 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
370 methods = authmethods_get();
371 packet_start(SSH2_MSG_USERAUTH_FAILURE);
372 packet_put_cstring(methods);
373 packet_put_char(0); /* XXX partial success, unused */
381 authmethods_get(void)
388 for (i = 0; authmethods[i] != NULL; i++) {
389 if (strcmp(authmethods[i]->name, "none") == 0)
391 if (authmethods[i]->enabled != NULL &&
392 *(authmethods[i]->enabled) != 0) {
393 if (buffer_len(&b) > 0)
394 buffer_append(&b, ",", 1);
395 buffer_append(&b, authmethods[i]->name,
396 strlen(authmethods[i]->name));
399 buffer_append(&b, "\0", 1);
400 list = xstrdup(buffer_ptr(&b));
406 authmethod_lookup(const char *name)
411 for (i = 0; authmethods[i] != NULL; i++)
412 if (authmethods[i]->enabled != NULL &&
413 *(authmethods[i]->enabled) != 0 &&
414 strcmp(name, authmethods[i]->name) == 0)
415 return authmethods[i];
416 debug2("Unrecognized authentication method name: %s",
417 name ? name : "NULL");