1 /* $OpenBSD: auth2.c,v 1.113 2006/08/03 03:34:41 deraadt 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.
29 #include <sys/types.h>
46 #include "pathnames.h"
53 #include "monitor_wrap.h"
56 extern ServerOptions options;
57 extern u_char *session_id2;
58 extern u_int session_id2_len;
59 extern Buffer loginmsg;
63 extern Authmethod method_none;
64 extern Authmethod method_pubkey;
65 extern Authmethod method_passwd;
66 extern Authmethod method_kbdint;
67 extern Authmethod method_hostbased;
69 extern Authmethod method_gssapi;
72 Authmethod *authmethods[] = {
86 static void input_service_request(int, u_int32_t, void *);
87 static void input_userauth_request(int, u_int32_t, void *);
90 static Authmethod *authmethod_lookup(const char *);
91 static char *authmethods_get(void);
92 int user_key_allowed(struct passwd *, Key *);
95 * loop until authctxt->success == TRUE
99 do_authentication2(Authctxt *authctxt)
101 /* challenge-response is implemented via keyboard interactive */
102 if (options.challenge_response_authentication)
103 options.kbd_interactive_authentication = 1;
105 dispatch_init(&dispatch_protocol_error);
106 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
107 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
112 input_service_request(int type, u_int32_t seq, void *ctxt)
114 Authctxt *authctxt = ctxt;
117 char *service = packet_get_string(&len);
120 if (authctxt == NULL)
121 fatal("input_service_request: no authctxt");
123 if (strcmp(service, "ssh-userauth") == 0) {
124 if (!authctxt->success) {
126 /* now we can handle user-auth requests */
127 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
130 /* XXX all other service requests are denied */
133 packet_start(SSH2_MSG_SERVICE_ACCEPT);
134 packet_put_cstring(service);
138 debug("bad service request %s", service);
139 packet_disconnect("bad service request %s", service);
146 input_userauth_request(int type, u_int32_t seq, void *ctxt)
148 Authctxt *authctxt = ctxt;
149 Authmethod *m = NULL;
150 char *user, *service, *method, *style = NULL;
151 int authenticated = 0;
152 #ifdef HAVE_LOGIN_CAP
154 const char *from_host, *from_ip;
156 from_host = get_canonical_hostname(options.use_dns);
157 from_ip = get_remote_ipaddr();
160 if (authctxt == NULL)
161 fatal("input_userauth_request: no authctxt");
163 user = packet_get_string(NULL);
164 service = packet_get_string(NULL);
165 method = packet_get_string(NULL);
166 debug("userauth-request for user %s service %s method %s", user, service, method);
167 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
169 if ((style = strchr(user, ':')) != NULL)
172 if (authctxt->attempt++ == 0) {
173 /* setup auth context */
174 authctxt->pw = PRIVSEP(getpwnamallow(user));
175 authctxt->user = xstrdup(user);
176 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
178 debug2("input_userauth_request: setting up authctxt for %s", user);
180 logit("input_userauth_request: invalid user %s", user);
181 authctxt->pw = fakepw();
182 #ifdef SSH_AUDIT_EVENTS
183 PRIVSEP(audit_event(SSH_INVALID_USER));
188 PRIVSEP(start_pam(authctxt));
190 setproctitle("%s%s", authctxt->valid ? user : "unknown",
191 use_privsep ? " [net]" : "");
192 authctxt->service = xstrdup(service);
193 authctxt->style = style ? xstrdup(style) : NULL;
195 mm_inform_authserv(service, style);
196 } else if (strcmp(user, authctxt->user) != 0 ||
197 strcmp(service, authctxt->service) != 0) {
198 packet_disconnect("Change of username or service not allowed: "
199 "(%s,%s) -> (%s,%s)",
200 authctxt->user, authctxt->service, user, service);
203 #ifdef HAVE_LOGIN_CAP
204 if (authctxt->pw != NULL) {
205 lc = login_getpwclass(authctxt->pw);
207 lc = login_getclassbyname(NULL, authctxt->pw);
208 if (!auth_hostok(lc, from_host, from_ip)) {
209 logit("Denied connection for %.200s from %.200s [%.200s].",
210 authctxt->pw->pw_name, from_host, from_ip);
211 packet_disconnect("Sorry, you are not allowed to connect.");
213 if (!auth_timeok(lc, time(NULL))) {
214 logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
215 authctxt->pw->pw_name, from_host);
216 packet_disconnect("Logins not available right now.");
221 #endif /* HAVE_LOGIN_CAP */
224 auth2_challenge_stop(authctxt);
227 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
228 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
231 authctxt->postponed = 0;
233 /* try to authenticate user */
234 m = authmethod_lookup(method);
236 debug2("input_userauth_request: try method %s", method);
237 authenticated = m->userauth(authctxt);
239 userauth_finish(authctxt, authenticated, method);
247 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
251 if (!authctxt->valid && authenticated)
252 fatal("INTERNAL ERROR: authenticated invalid user %s",
255 /* Special handling for root */
256 if (authenticated && authctxt->pw->pw_uid == 0 &&
257 !auth_root_allowed(method)) {
259 #ifdef SSH_AUDIT_EVENTS
260 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
265 if (options.use_pam && authenticated) {
266 if (!PRIVSEP(do_pam_account())) {
267 /* if PAM returned a message, send it to the user */
268 if (buffer_len(&loginmsg) > 0) {
269 buffer_append(&loginmsg, "\0", 1);
270 userauth_send_banner(buffer_ptr(&loginmsg));
273 fatal("Access denied for user %s by PAM account "
274 "configuration", authctxt->user);
280 if (authenticated && cray_access_denied(authctxt->user)) {
282 fatal("Access denied for user %s.",authctxt->user);
286 /* Log before sending the reply */
287 auth_log(authctxt, authenticated, method, " ssh2");
289 if (authctxt->postponed)
292 /* XXX todo: check if multiple auth methods are needed */
293 if (authenticated == 1) {
294 /* turn off userauth */
295 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
296 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
299 /* now we can break out */
300 authctxt->success = 1;
302 if (authctxt->failures++ > options.max_authtries) {
303 #ifdef SSH_AUDIT_EVENTS
304 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
306 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
308 methods = authmethods_get();
309 packet_start(SSH2_MSG_USERAUTH_FAILURE);
310 packet_put_cstring(methods);
311 packet_put_char(0); /* XXX partial success, unused */
321 authmethods_get(void)
328 for (i = 0; authmethods[i] != NULL; i++) {
329 if (strcmp(authmethods[i]->name, "none") == 0)
331 if (authmethods[i]->enabled != NULL &&
332 *(authmethods[i]->enabled) != 0) {
333 if (buffer_len(&b) > 0)
334 buffer_append(&b, ",", 1);
335 buffer_append(&b, authmethods[i]->name,
336 strlen(authmethods[i]->name));
339 buffer_append(&b, "\0", 1);
340 list = xstrdup(buffer_ptr(&b));
346 authmethod_lookup(const char *name)
351 for (i = 0; authmethods[i] != NULL; i++)
352 if (authmethods[i]->enabled != NULL &&
353 *(authmethods[i]->enabled) != 0 &&
354 strcmp(name, authmethods[i]->name) == 0)
355 return authmethods[i];
356 debug2("Unrecognized authentication method name: %s",
357 name ? name : "NULL");