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_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);
235 if (user[0] == '\0') {
236 debug("received empty username for %s", method);
237 if (strcmp(method, "gssapi-keyex") == 0) {
239 PRIVSEP(ssh_gssapi_localname(&lname));
240 if (lname && lname[0] != '\0') {
243 debug("set username to %s from gssapi context", user);
245 debug("failed to set username from gssapi context");
246 packet_send_debug("failed to set username from gssapi context");
252 debug("userauth-request for user %s service %s method %s",
253 user[0] ? user : "<implicit>", service, method);
255 logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s",
256 get_remote_ipaddr(), get_remote_port(),
257 user[0] ? user : "<implicit>");
260 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
262 if ((style = strchr(user, ':')) != NULL)
265 /* If first time or username changed or empty username,
266 setup/reset authentication context. */
267 if ((authctxt->attempt++ == 0) ||
268 (strcmp(user, authctxt->user) != 0) ||
269 (strcmp(user, "") == 0)) {
270 if (authctxt->user) {
271 xfree(authctxt->user);
272 authctxt->user = NULL;
275 authctxt->user = xstrdup(user);
276 if (strcmp(service, "ssh-connection") != 0) {
277 packet_disconnect("Unsupported service %s", service);
280 /* If we're going to set the username based on the
281 GSSAPI context later, then wait until then to
282 verify it. Just put in placeholders for now. */
283 if ((strcmp(user, "") == 0) &&
284 ((strcmp(method, "gssapi") == 0) ||
285 (strcmp(method, "gssapi-with-mic") == 0))) {
286 authctxt->pw = fakepw();
289 authctxt->pw = PRIVSEP(getpwnamallow(user));
292 debug2("input_userauth_request: setting up authctxt for %s", user);
294 logit("input_userauth_request: invalid user %s", user);
295 authctxt->pw = fakepw();
296 #ifdef SSH_AUDIT_EVENTS
297 PRIVSEP(audit_event(SSH_INVALID_USER));
301 } /* endif for setting username based on GSSAPI context */
305 PRIVSEP(start_pam(authctxt));
307 setproctitle("%s%s", authctxt->valid ? user : "unknown",
308 use_privsep ? " [net]" : "");
309 if (authctxt->attempt == 1) {
310 authctxt->service = xstrdup(service);
311 authctxt->style = style ? xstrdup(style) : NULL;
313 mm_inform_authserv(service, style);
317 if (strcmp(service, authctxt->service) != 0) {
318 packet_disconnect("Change of service not allowed: "
319 "(%s,%s) -> (%s,%s)",
320 authctxt->user, authctxt->service, user, service);
323 auth2_challenge_stop(authctxt);
325 auth2_jpake_stop(authctxt);
329 /* XXX move to auth2_gssapi_stop() */
330 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
331 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
334 authctxt->postponed = 0;
335 authctxt->server_caused_failure = 0;
337 /* try to authenticate user */
338 m = authmethod_lookup(method);
339 if (m != NULL && authctxt->failures < options.max_authtries) {
340 debug2("input_userauth_request: try method %s", method);
341 authenticated = m->userauth(authctxt);
343 userauth_finish(authctxt, authenticated, method);
351 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
355 if (!authctxt->valid && authenticated)
356 fatal("INTERNAL ERROR: authenticated invalid user %s",
359 /* Special handling for root */
360 if (authenticated && authctxt->pw->pw_uid == 0 &&
361 !auth_root_allowed(method)) {
363 #ifdef SSH_AUDIT_EVENTS
364 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
369 if (options.use_pam && authenticated) {
370 if (!PRIVSEP(do_pam_account())) {
371 /* if PAM returned a message, send it to the user */
372 if (buffer_len(&loginmsg) > 0) {
373 buffer_append(&loginmsg, "\0", 1);
374 userauth_send_banner(buffer_ptr(&loginmsg));
377 fatal("Access denied for user %s by PAM account "
378 "configuration", authctxt->user);
384 if (authenticated && cray_access_denied(authctxt->user)) {
386 fatal("Access denied for user %s.",authctxt->user);
390 /* Log before sending the reply */
391 auth_log(authctxt, authenticated, method, " ssh2");
393 if (authctxt->postponed)
396 /* XXX todo: check if multiple auth methods are needed */
397 if (authenticated == 1) {
398 /* turn off userauth */
399 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
400 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
403 /* now we can break out */
404 authctxt->success = 1;
406 /* Dont count server configuration issues against the client */
407 /* Allow initial try of "none" auth without failure penalty */
408 if (!authctxt->server_caused_failure &&
409 (authctxt->attempt > 1 || strcmp(method, "none") != 0))
410 authctxt->failures++;
411 if (authctxt->failures >= options.max_authtries) {
412 #ifdef SSH_AUDIT_EVENTS
413 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
415 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
417 methods = authmethods_get();
418 packet_start(SSH2_MSG_USERAUTH_FAILURE);
419 packet_put_cstring(methods);
420 packet_put_char(0); /* XXX partial success, unused */
428 authmethods_get(void)
435 for (i = 0; authmethods[i] != NULL; i++) {
436 if (strcmp(authmethods[i]->name, "none") == 0)
438 if (authmethods[i]->enabled != NULL &&
439 *(authmethods[i]->enabled) != 0) {
440 if (buffer_len(&b) > 0)
441 buffer_append(&b, ",", 1);
442 buffer_append(&b, authmethods[i]->name,
443 strlen(authmethods[i]->name));
446 buffer_append(&b, "\0", 1);
447 list = xstrdup(buffer_ptr(&b));
453 authmethod_lookup(const char *name)
458 for (i = 0; authmethods[i] != NULL; i++)
459 if (authmethods[i]->enabled != NULL &&
460 *(authmethods[i]->enabled) != 0 &&
461 strcmp(name, authmethods[i]->name) == 0)
462 return authmethods[i];
463 debug2("Unrecognized authentication method name: %s",
464 name ? name : "NULL");