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"
56 #include "monitor_wrap.h"
59 extern ServerOptions options;
60 extern u_char *session_id2;
61 extern u_int session_id2_len;
62 extern Buffer loginmsg;
66 extern Authmethod method_none;
67 extern Authmethod method_pubkey;
68 extern Authmethod method_passwd;
69 extern Authmethod method_kbdint;
70 extern Authmethod method_hostbased;
72 extern Authmethod method_gssapi;
75 extern Authmethod method_jpake;
78 Authmethod *authmethods[] = {
95 static void input_service_request(int, u_int32_t, void *);
96 static void input_userauth_request(int, u_int32_t, void *);
99 static Authmethod *authmethod_lookup(const char *);
100 static char *authmethods_get(void);
103 auth2_read_banner(void)
110 if ((fd = open(options.banner, O_RDONLY)) == -1)
112 if (fstat(fd, &st) == -1) {
116 if (st.st_size > 1*1024*1024) {
121 len = (size_t)st.st_size; /* truncate */
122 banner = xmalloc(len + 1);
123 n = atomicio(read, fd, banner, len);
136 userauth_send_banner(const char *msg)
138 if (datafellows & SSH_BUG_BANNER)
141 packet_start(SSH2_MSG_USERAUTH_BANNER);
142 packet_put_cstring(msg);
143 packet_put_cstring(""); /* language, unused */
145 debug("%s: sent", __func__);
149 userauth_banner(void)
153 if (options.banner == NULL ||
154 strcasecmp(options.banner, "none") == 0 ||
155 (datafellows & SSH_BUG_BANNER) != 0)
158 if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
160 userauth_send_banner(banner);
168 * loop until authctxt->success == TRUE
171 do_authentication2(Authctxt *authctxt)
173 dispatch_init(&dispatch_protocol_error);
174 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
175 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
180 input_service_request(int type, u_int32_t seq, void *ctxt)
182 Authctxt *authctxt = ctxt;
185 char *service = packet_get_string(&len);
188 if (authctxt == NULL)
189 fatal("input_service_request: no authctxt");
191 if (strcmp(service, "ssh-userauth") == 0) {
192 if (!authctxt->success) {
194 /* now we can handle user-auth requests */
195 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
198 /* XXX all other service requests are denied */
201 packet_start(SSH2_MSG_SERVICE_ACCEPT);
202 packet_put_cstring(service);
206 debug("bad service request %s", service);
207 packet_disconnect("bad service request %s", service);
214 input_userauth_request(int type, u_int32_t seq, void *ctxt)
216 Authctxt *authctxt = ctxt;
217 Authmethod *m = NULL;
218 char *user, *service, *method, *style = NULL;
219 int authenticated = 0;
220 #ifdef HAVE_LOGIN_CAP
222 const char *from_host, *from_ip;
224 from_host = get_canonical_hostname(options.use_dns);
225 from_ip = get_remote_ipaddr();
228 if (authctxt == NULL)
229 fatal("input_userauth_request: no authctxt");
231 user = packet_get_string(NULL);
232 service = packet_get_string(NULL);
233 method = packet_get_string(NULL);
234 debug("userauth-request for user %s service %s method %s", user, service, method);
235 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
237 if ((style = strchr(user, ':')) != NULL)
240 if (authctxt->attempt++ == 0) {
241 /* setup auth context */
242 authctxt->pw = PRIVSEP(getpwnamallow(user));
243 authctxt->user = xstrdup(user);
244 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
246 debug2("input_userauth_request: setting up authctxt for %s", user);
248 logit("input_userauth_request: invalid user %s", user);
249 authctxt->pw = fakepw();
250 #ifdef SSH_AUDIT_EVENTS
251 PRIVSEP(audit_event(SSH_INVALID_USER));
256 PRIVSEP(start_pam(authctxt));
258 setproctitle("%s%s", authctxt->valid ? user : "unknown",
259 use_privsep ? " [net]" : "");
260 authctxt->service = xstrdup(service);
261 authctxt->style = style ? xstrdup(style) : NULL;
263 mm_inform_authserv(service, style);
265 } else if (strcmp(user, authctxt->user) != 0 ||
266 strcmp(service, authctxt->service) != 0) {
267 packet_disconnect("Change of username or service not allowed: "
268 "(%s,%s) -> (%s,%s)",
269 authctxt->user, authctxt->service, user, service);
272 #ifdef HAVE_LOGIN_CAP
273 if (authctxt->pw != NULL) {
274 lc = login_getpwclass(authctxt->pw);
276 lc = login_getclassbyname(NULL, authctxt->pw);
277 if (!auth_hostok(lc, from_host, from_ip)) {
278 logit("Denied connection for %.200s from %.200s [%.200s].",
279 authctxt->pw->pw_name, from_host, from_ip);
280 packet_disconnect("Sorry, you are not allowed to connect.");
282 if (!auth_timeok(lc, time(NULL))) {
283 logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
284 authctxt->pw->pw_name, from_host);
285 packet_disconnect("Logins not available right now.");
290 #endif /* HAVE_LOGIN_CAP */
293 auth2_challenge_stop(authctxt);
295 auth2_jpake_stop(authctxt);
299 /* XXX move to auth2_gssapi_stop() */
300 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
301 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
304 authctxt->postponed = 0;
306 /* try to authenticate user */
307 m = authmethod_lookup(method);
308 if (m != NULL && authctxt->failures < options.max_authtries) {
309 debug2("input_userauth_request: try method %s", method);
310 authenticated = m->userauth(authctxt);
312 userauth_finish(authctxt, authenticated, method);
320 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
324 if (!authctxt->valid && authenticated)
325 fatal("INTERNAL ERROR: authenticated invalid user %s",
328 /* Special handling for root */
329 if (authenticated && authctxt->pw->pw_uid == 0 &&
330 !auth_root_allowed(method)) {
332 #ifdef SSH_AUDIT_EVENTS
333 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
338 if (options.use_pam && authenticated) {
339 if (!PRIVSEP(do_pam_account())) {
340 /* if PAM returned a message, send it to the user */
341 if (buffer_len(&loginmsg) > 0) {
342 buffer_append(&loginmsg, "\0", 1);
343 userauth_send_banner(buffer_ptr(&loginmsg));
346 fatal("Access denied for user %s by PAM account "
347 "configuration", authctxt->user);
353 if (authenticated && cray_access_denied(authctxt->user)) {
355 fatal("Access denied for user %s.",authctxt->user);
359 /* Log before sending the reply */
360 auth_log(authctxt, authenticated, method, " ssh2");
362 if (authctxt->postponed)
365 /* XXX todo: check if multiple auth methods are needed */
366 if (authenticated == 1) {
367 /* turn off userauth */
368 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
369 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
372 /* now we can break out */
373 authctxt->success = 1;
376 /* Allow initial try of "none" auth without failure penalty */
377 if (authctxt->attempt > 1 || strcmp(method, "none") != 0)
378 authctxt->failures++;
379 if (authctxt->failures >= options.max_authtries) {
380 #ifdef SSH_AUDIT_EVENTS
381 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
383 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
385 methods = authmethods_get();
386 packet_start(SSH2_MSG_USERAUTH_FAILURE);
387 packet_put_cstring(methods);
388 packet_put_char(0); /* XXX partial success, unused */
396 authmethods_get(void)
403 for (i = 0; authmethods[i] != NULL; i++) {
404 if (strcmp(authmethods[i]->name, "none") == 0)
406 if (authmethods[i]->enabled != NULL &&
407 *(authmethods[i]->enabled) != 0) {
408 if (buffer_len(&b) > 0)
409 buffer_append(&b, ",", 1);
410 buffer_append(&b, authmethods[i]->name,
411 strlen(authmethods[i]->name));
414 buffer_append(&b, "\0", 1);
415 list = xstrdup(buffer_ptr(&b));
421 authmethod_lookup(const char *name)
426 for (i = 0; authmethods[i] != NULL; i++)
427 if (authmethods[i]->enabled != NULL &&
428 *(authmethods[i]->enabled) != 0 &&
429 strcmp(name, authmethods[i]->name) == 0)
430 return authmethods[i];
431 debug2("Unrecognized authentication method name: %s",
432 name ? name : "NULL");