1 /* $OpenBSD: auth2.c,v 1.122 2010/08/31 09:58:37 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"
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_gsskeyex;
73 extern Authmethod method_gssapi;
76 extern Authmethod method_jpake;
79 Authmethod *authmethods[] = {
97 static void input_service_request(int, u_int32_t, void *);
98 static void input_userauth_request(int, u_int32_t, void *);
101 static Authmethod *authmethod_lookup(const char *);
102 static char *authmethods_get(void);
105 auth2_read_banner(void)
112 if ((fd = open(options.banner, O_RDONLY)) == -1)
114 if (fstat(fd, &st) == -1) {
118 if (st.st_size > 1*1024*1024) {
123 len = (size_t)st.st_size; /* truncate */
124 banner = xmalloc(len + 1);
125 n = atomicio(read, fd, banner, len);
138 userauth_send_banner(const char *msg)
140 if (datafellows & SSH_BUG_BANNER)
143 packet_start(SSH2_MSG_USERAUTH_BANNER);
144 packet_put_cstring(msg);
145 packet_put_cstring(""); /* language, unused */
147 debug("%s: sent", __func__);
151 userauth_banner(void)
155 if (options.banner == NULL ||
156 strcasecmp(options.banner, "none") == 0 ||
157 (datafellows & SSH_BUG_BANNER) != 0)
160 if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
162 userauth_send_banner(banner);
170 * loop until authctxt->success == TRUE
173 do_authentication2(Authctxt *authctxt)
175 dispatch_init(&dispatch_protocol_error);
176 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
177 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
182 input_service_request(int type, u_int32_t seq, void *ctxt)
184 Authctxt *authctxt = ctxt;
187 char *service = packet_get_cstring(&len);
190 if (authctxt == NULL)
191 fatal("input_service_request: no authctxt");
193 if (strcmp(service, "ssh-userauth") == 0) {
194 if (!authctxt->success) {
196 /* now we can handle user-auth requests */
197 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
200 /* XXX all other service requests are denied */
203 packet_start(SSH2_MSG_SERVICE_ACCEPT);
204 packet_put_cstring(service);
208 debug("bad service request %s", service);
209 packet_disconnect("bad service request %s", service);
216 input_userauth_request(int type, u_int32_t seq, void *ctxt)
218 Authctxt *authctxt = ctxt;
219 Authmethod *m = NULL;
220 char *user, *service, *method, *style = NULL;
221 int authenticated = 0;
223 if (authctxt == NULL)
224 fatal("input_userauth_request: no authctxt");
226 user = packet_get_cstring(NULL);
227 service = packet_get_cstring(NULL);
228 method = packet_get_cstring(NULL);
229 debug("userauth-request for user %s service %s method %s", user, service, method);
230 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
232 if ((style = strchr(user, ':')) != NULL)
235 if (authctxt->attempt++ == 0) {
236 /* setup auth context */
237 authctxt->pw = PRIVSEP(getpwnamallow(user));
238 authctxt->user = xstrdup(user);
239 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
241 debug2("input_userauth_request: setting up authctxt for %s", user);
243 logit("input_userauth_request: invalid user %s", user);
244 authctxt->pw = fakepw();
245 #ifdef SSH_AUDIT_EVENTS
246 PRIVSEP(audit_event(SSH_INVALID_USER));
251 PRIVSEP(start_pam(authctxt));
253 setproctitle("%s%s", authctxt->valid ? user : "unknown",
254 use_privsep ? " [net]" : "");
255 authctxt->service = xstrdup(service);
256 authctxt->style = style ? xstrdup(style) : NULL;
258 mm_inform_authserv(service, style);
260 } else if (strcmp(user, authctxt->user) != 0 ||
261 strcmp(service, authctxt->service) != 0) {
262 packet_disconnect("Change of username or service not allowed: "
263 "(%s,%s) -> (%s,%s)",
264 authctxt->user, authctxt->service, user, service);
267 auth2_challenge_stop(authctxt);
269 auth2_jpake_stop(authctxt);
273 /* XXX move to auth2_gssapi_stop() */
274 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
275 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
278 authctxt->postponed = 0;
279 authctxt->server_caused_failure = 0;
281 /* try to authenticate user */
282 m = authmethod_lookup(method);
283 if (m != NULL && authctxt->failures < options.max_authtries) {
284 debug2("input_userauth_request: try method %s", method);
285 authenticated = m->userauth(authctxt);
287 userauth_finish(authctxt, authenticated, method);
295 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
299 if (!authctxt->valid && authenticated)
300 fatal("INTERNAL ERROR: authenticated invalid user %s",
303 /* Special handling for root */
304 if (authenticated && authctxt->pw->pw_uid == 0 &&
305 !auth_root_allowed(method)) {
307 #ifdef SSH_AUDIT_EVENTS
308 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
313 if (options.use_pam && authenticated) {
314 if (!PRIVSEP(do_pam_account())) {
315 /* if PAM returned a message, send it to the user */
316 if (buffer_len(&loginmsg) > 0) {
317 buffer_append(&loginmsg, "\0", 1);
318 userauth_send_banner(buffer_ptr(&loginmsg));
321 fatal("Access denied for user %s by PAM account "
322 "configuration", authctxt->user);
328 if (authenticated && cray_access_denied(authctxt->user)) {
330 fatal("Access denied for user %s.",authctxt->user);
334 /* Log before sending the reply */
335 auth_log(authctxt, authenticated, method, " ssh2");
337 if (authctxt->postponed)
340 /* XXX todo: check if multiple auth methods are needed */
341 if (authenticated == 1) {
342 /* turn off userauth */
343 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
344 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
347 /* now we can break out */
348 authctxt->success = 1;
351 /* Allow initial try of "none" auth without failure penalty */
352 if (!authctxt->server_caused_failure &&
353 (authctxt->attempt > 1 || strcmp(method, "none") != 0))
354 authctxt->failures++;
355 if (authctxt->failures >= options.max_authtries) {
356 #ifdef SSH_AUDIT_EVENTS
357 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
359 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
361 methods = authmethods_get();
362 packet_start(SSH2_MSG_USERAUTH_FAILURE);
363 packet_put_cstring(methods);
364 packet_put_char(0); /* XXX partial success, unused */
372 authmethods_get(void)
379 for (i = 0; authmethods[i] != NULL; i++) {
380 if (strcmp(authmethods[i]->name, "none") == 0)
382 if (authmethods[i]->enabled != NULL &&
383 *(authmethods[i]->enabled) != 0) {
384 if (buffer_len(&b) > 0)
385 buffer_append(&b, ",", 1);
386 buffer_append(&b, authmethods[i]->name,
387 strlen(authmethods[i]->name));
390 buffer_append(&b, "\0", 1);
391 list = xstrdup(buffer_ptr(&b));
397 authmethod_lookup(const char *name)
402 for (i = 0; authmethods[i] != NULL; i++)
403 if (authmethods[i]->enabled != NULL &&
404 *(authmethods[i]->enabled) != 0 &&
405 strcmp(name, authmethods[i]->name) == 0)
406 return authmethods[i];
407 debug2("Unrecognized authentication method name: %s",
408 name ? name : "NULL");