1 /* $OpenBSD: auth2.c,v 1.123 2011/03/10 02:52:57 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_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_cstring(&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;
221 if (authctxt == NULL)
222 fatal("input_userauth_request: no authctxt");
224 user = packet_get_cstring(NULL);
225 service = packet_get_cstring(NULL);
226 method = packet_get_cstring(NULL);
227 debug("userauth-request for user %s service %s method %s", user, service, method);
228 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
230 if ((style = strchr(user, ':')) != NULL)
233 if (authctxt->attempt++ == 0) {
234 /* setup auth context */
235 authctxt->pw = PRIVSEP(getpwnamallow(user));
236 authctxt->user = xstrdup(user);
237 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
239 debug2("input_userauth_request: setting up authctxt for %s", user);
241 logit("input_userauth_request: invalid user %s", user);
242 authctxt->pw = fakepw();
243 #ifdef SSH_AUDIT_EVENTS
244 PRIVSEP(audit_event(SSH_INVALID_USER));
249 PRIVSEP(start_pam(authctxt));
251 setproctitle("%s%s", authctxt->valid ? user : "unknown",
252 use_privsep ? " [net]" : "");
253 authctxt->service = xstrdup(service);
254 authctxt->style = style ? xstrdup(style) : NULL;
256 mm_inform_authserv(service, style);
258 } else if (strcmp(user, authctxt->user) != 0 ||
259 strcmp(service, authctxt->service) != 0) {
260 packet_disconnect("Change of username or service not allowed: "
261 "(%s,%s) -> (%s,%s)",
262 authctxt->user, authctxt->service, user, service);
265 auth2_challenge_stop(authctxt);
267 auth2_jpake_stop(authctxt);
271 /* XXX move to auth2_gssapi_stop() */
272 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
273 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
276 authctxt->postponed = 0;
277 authctxt->server_caused_failure = 0;
279 /* try to authenticate user */
280 m = authmethod_lookup(method);
281 if (m != NULL && authctxt->failures < options.max_authtries) {
282 debug2("input_userauth_request: try method %s", method);
283 authenticated = m->userauth(authctxt);
285 userauth_finish(authctxt, authenticated, method);
293 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
297 if (!authctxt->valid && authenticated)
298 fatal("INTERNAL ERROR: authenticated invalid user %s",
301 /* Special handling for root */
302 if (authenticated && authctxt->pw->pw_uid == 0 &&
303 !auth_root_allowed(method)) {
305 #ifdef SSH_AUDIT_EVENTS
306 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
311 if (options.use_pam && authenticated) {
312 if (!PRIVSEP(do_pam_account())) {
313 /* if PAM returned a message, send it to the user */
314 if (buffer_len(&loginmsg) > 0) {
315 buffer_append(&loginmsg, "\0", 1);
316 userauth_send_banner(buffer_ptr(&loginmsg));
319 fatal("Access denied for user %s by PAM account "
320 "configuration", authctxt->user);
326 if (authenticated && cray_access_denied(authctxt->user)) {
328 fatal("Access denied for user %s.",authctxt->user);
332 /* Log before sending the reply */
333 auth_log(authctxt, authenticated, method, " ssh2");
335 if (authctxt->postponed)
338 /* XXX todo: check if multiple auth methods are needed */
339 if (authenticated == 1) {
340 /* turn off userauth */
341 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
342 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
345 /* now we can break out */
346 authctxt->success = 1;
349 /* Allow initial try of "none" auth without failure penalty */
350 if (!authctxt->server_caused_failure &&
351 (authctxt->attempt > 1 || strcmp(method, "none") != 0))
352 authctxt->failures++;
353 if (authctxt->failures >= options.max_authtries) {
354 #ifdef SSH_AUDIT_EVENTS
355 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
357 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
359 methods = authmethods_get();
360 packet_start(SSH2_MSG_USERAUTH_FAILURE);
361 packet_put_cstring(methods);
362 packet_put_char(0); /* XXX partial success, unused */
370 authmethods_get(void)
377 for (i = 0; authmethods[i] != NULL; i++) {
378 if (strcmp(authmethods[i]->name, "none") == 0)
380 if (authmethods[i]->enabled != NULL &&
381 *(authmethods[i]->enabled) != 0) {
382 if (buffer_len(&b) > 0)
383 buffer_append(&b, ",", 1);
384 buffer_append(&b, authmethods[i]->name,
385 strlen(authmethods[i]->name));
388 buffer_append(&b, "\0", 1);
389 list = xstrdup(buffer_ptr(&b));
395 authmethod_lookup(const char *name)
400 for (i = 0; authmethods[i] != NULL; i++)
401 if (authmethods[i]->enabled != NULL &&
402 *(authmethods[i]->enabled) != 0 &&
403 strcmp(name, authmethods[i]->name) == 0)
404 return authmethods[i];
405 debug2("Unrecognized authentication method name: %s",
406 name ? name : "NULL");