1 /* $OpenBSD: auth2.c,v 1.121 2009/06/22 05:39:28 dtucker 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_gssapi;
76 extern Authmethod method_jpake;
79 Authmethod *authmethods[] = {
96 static void input_service_request(int, u_int32_t, void *);
97 static void input_userauth_request(int, u_int32_t, void *);
100 static Authmethod *authmethod_lookup(const char *);
101 static char *authmethods_get(void);
104 auth2_read_banner(void)
111 if ((fd = open(options.banner, O_RDONLY)) == -1)
113 if (fstat(fd, &st) == -1) {
117 if (st.st_size > 1*1024*1024) {
122 len = (size_t)st.st_size; /* truncate */
123 banner = xmalloc(len + 1);
124 n = atomicio(read, fd, banner, len);
137 userauth_send_banner(const char *msg)
139 if (datafellows & SSH_BUG_BANNER)
142 packet_start(SSH2_MSG_USERAUTH_BANNER);
143 packet_put_cstring(msg);
144 packet_put_cstring(""); /* language, unused */
146 debug("%s: sent", __func__);
150 userauth_banner(void)
154 if (options.banner == NULL ||
155 strcasecmp(options.banner, "none") == 0 ||
156 (datafellows & SSH_BUG_BANNER) != 0)
159 if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
161 userauth_send_banner(banner);
169 * loop until authctxt->success == TRUE
172 do_authentication2(Authctxt *authctxt)
174 dispatch_init(&dispatch_protocol_error);
175 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
176 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
181 input_service_request(int type, u_int32_t seq, void *ctxt)
183 Authctxt *authctxt = ctxt;
186 char *service = packet_get_string(&len);
189 if (authctxt == NULL)
190 fatal("input_service_request: no authctxt");
192 if (strcmp(service, "ssh-userauth") == 0) {
193 if (!authctxt->success) {
195 /* now we can handle user-auth requests */
196 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
199 /* XXX all other service requests are denied */
202 packet_start(SSH2_MSG_SERVICE_ACCEPT);
203 packet_put_cstring(service);
207 debug("bad service request %s", service);
208 packet_disconnect("bad service request %s", service);
215 input_userauth_request(int type, u_int32_t seq, void *ctxt)
217 Authctxt *authctxt = ctxt;
218 Authmethod *m = NULL;
219 char *user, *service, *method, *style = NULL;
220 int authenticated = 0;
221 #ifdef HAVE_LOGIN_CAP
223 const char *from_host, *from_ip;
225 from_host = get_canonical_hostname(options.use_dns);
226 from_ip = get_remote_ipaddr();
229 if (authctxt == NULL)
230 fatal("input_userauth_request: no authctxt");
232 user = packet_get_string(NULL);
233 service = packet_get_string(NULL);
234 method = packet_get_string(NULL);
235 debug("userauth-request for user %s service %s method %s", user, service, method);
236 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
238 if ((style = strchr(user, ':')) != NULL)
241 if (authctxt->attempt++ == 0) {
242 /* setup auth context */
243 authctxt->pw = PRIVSEP(getpwnamallow(user));
244 authctxt->user = xstrdup(user);
245 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
247 debug2("input_userauth_request: setting up authctxt for %s", user);
249 logit("input_userauth_request: invalid user %s", user);
250 authctxt->pw = fakepw();
251 #ifdef SSH_AUDIT_EVENTS
252 PRIVSEP(audit_event(SSH_INVALID_USER));
257 PRIVSEP(start_pam(authctxt));
259 setproctitle("%s%s", authctxt->valid ? user : "unknown",
260 use_privsep ? " [net]" : "");
261 authctxt->service = xstrdup(service);
262 authctxt->style = style ? xstrdup(style) : NULL;
264 mm_inform_authserv(service, style);
266 } else if (strcmp(user, authctxt->user) != 0 ||
267 strcmp(service, authctxt->service) != 0) {
268 packet_disconnect("Change of username or service not allowed: "
269 "(%s,%s) -> (%s,%s)",
270 authctxt->user, authctxt->service, user, service);
273 #ifdef HAVE_LOGIN_CAP
274 if (authctxt->pw != NULL) {
275 lc = login_getpwclass(authctxt->pw);
277 lc = login_getclassbyname(NULL, authctxt->pw);
278 if (!auth_hostok(lc, from_host, from_ip)) {
279 logit("Denied connection for %.200s from %.200s [%.200s].",
280 authctxt->pw->pw_name, from_host, from_ip);
281 packet_disconnect("Sorry, you are not allowed to connect.");
283 if (!auth_timeok(lc, time(NULL))) {
284 logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
285 authctxt->pw->pw_name, from_host);
286 packet_disconnect("Logins not available right now.");
291 #endif /* HAVE_LOGIN_CAP */
294 auth2_challenge_stop(authctxt);
296 auth2_jpake_stop(authctxt);
300 /* XXX move to auth2_gssapi_stop() */
301 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
302 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
305 authctxt->postponed = 0;
307 /* try to authenticate user */
308 m = authmethod_lookup(method);
309 if (m != NULL && authctxt->failures < options.max_authtries) {
310 debug2("input_userauth_request: try method %s", method);
311 authenticated = m->userauth(authctxt);
313 userauth_finish(authctxt, authenticated, method);
321 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
325 if (!authctxt->valid && authenticated)
326 fatal("INTERNAL ERROR: authenticated invalid user %s",
329 /* Special handling for root */
330 if (authenticated && authctxt->pw->pw_uid == 0 &&
331 !auth_root_allowed(method)) {
333 #ifdef SSH_AUDIT_EVENTS
334 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
339 if (options.use_pam && authenticated) {
340 if (!PRIVSEP(do_pam_account())) {
341 /* if PAM returned a message, send it to the user */
342 if (buffer_len(&loginmsg) > 0) {
343 buffer_append(&loginmsg, "\0", 1);
344 userauth_send_banner(buffer_ptr(&loginmsg));
347 fatal("Access denied for user %s by PAM account "
348 "configuration", authctxt->user);
354 if (authenticated && cray_access_denied(authctxt->user)) {
356 fatal("Access denied for user %s.",authctxt->user);
360 /* Log before sending the reply */
361 auth_log(authctxt, authenticated, method, " ssh2");
363 if (authctxt->postponed)
366 /* XXX todo: check if multiple auth methods are needed */
367 if (authenticated == 1) {
368 /* turn off userauth */
369 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
370 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
373 /* now we can break out */
374 authctxt->success = 1;
377 /* Allow initial try of "none" auth without failure penalty */
378 if (authctxt->attempt > 1 || strcmp(method, "none") != 0)
379 authctxt->failures++;
380 if (authctxt->failures >= options.max_authtries) {
381 #ifdef SSH_AUDIT_EVENTS
382 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
384 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
386 methods = authmethods_get();
387 packet_start(SSH2_MSG_USERAUTH_FAILURE);
388 packet_put_cstring(methods);
389 packet_put_char(0); /* XXX partial success, unused */
397 authmethods_get(void)
404 for (i = 0; authmethods[i] != NULL; i++) {
405 if (strcmp(authmethods[i]->name, "none") == 0)
407 if (authmethods[i]->enabled != NULL &&
408 *(authmethods[i]->enabled) != 0) {
409 if (buffer_len(&b) > 0)
410 buffer_append(&b, ",", 1);
411 buffer_append(&b, authmethods[i]->name,
412 strlen(authmethods[i]->name));
415 buffer_append(&b, "\0", 1);
416 list = xstrdup(buffer_ptr(&b));
422 authmethod_lookup(const char *name)
427 for (i = 0; authmethods[i] != NULL; i++)
428 if (authmethods[i]->enabled != NULL &&
429 *(authmethods[i]->enabled) != 0 &&
430 strcmp(name, authmethods[i]->name) == 0)
431 return authmethods[i];
432 debug2("Unrecognized authentication method name: %s",
433 name ? name : "NULL");