2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 RCSID("$OpenBSD: auth2.c,v 1.107 2004/07/28 09:40:29 markus Exp $");
38 #include "pathnames.h"
39 #include "monitor_wrap.h"
47 extern ServerOptions options;
48 extern u_char *session_id2;
49 extern u_int session_id2_len;
50 extern Buffer loginmsg;
54 extern Authmethod method_none;
55 extern Authmethod method_pubkey;
56 extern Authmethod method_passwd;
57 extern Authmethod method_kbdint;
58 extern Authmethod method_hostbased;
60 extern Authmethod method_gssapi;
63 Authmethod *authmethods[] = {
77 static void input_service_request(int, u_int32_t, void *);
78 static void input_userauth_request(int, u_int32_t, void *);
81 static Authmethod *authmethod_lookup(const char *);
82 static char *authmethods_get(void);
83 int user_key_allowed(struct passwd *, Key *);
86 * loop until authctxt->success == TRUE
90 do_authentication2(Authctxt *authctxt)
92 /* challenge-response is implemented via keyboard interactive */
93 if (options.challenge_response_authentication)
94 options.kbd_interactive_authentication = 1;
96 dispatch_init(&dispatch_protocol_error);
97 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
98 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
102 input_service_request(int type, u_int32_t seq, void *ctxt)
104 Authctxt *authctxt = ctxt;
107 char *service = packet_get_string(&len);
110 if (authctxt == NULL)
111 fatal("input_service_request: no authctxt");
113 if (strcmp(service, "ssh-userauth") == 0) {
114 if (!authctxt->success) {
116 /* now we can handle user-auth requests */
117 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
120 /* XXX all other service requests are denied */
123 packet_start(SSH2_MSG_SERVICE_ACCEPT);
124 packet_put_cstring(service);
128 debug("bad service request %s", service);
129 packet_disconnect("bad service request %s", service);
135 input_userauth_request(int type, u_int32_t seq, void *ctxt)
137 Authctxt *authctxt = ctxt;
138 Authmethod *m = NULL;
139 char *user, *service, *method, *style = NULL;
140 int authenticated = 0;
141 #ifdef HAVE_LOGIN_CAP
143 const char *from_host, *from_ip;
145 from_host = get_canonical_hostname(options.use_dns);
146 from_ip = get_remote_ipaddr();
149 if (authctxt == NULL)
150 fatal("input_userauth_request: no authctxt");
152 user = packet_get_string(NULL);
153 service = packet_get_string(NULL);
154 method = packet_get_string(NULL);
155 debug("userauth-request for user %s service %s method %s", user, service, method);
156 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
158 if ((style = strchr(user, ':')) != NULL)
161 if (authctxt->attempt++ == 0) {
162 /* setup auth context */
163 authctxt->pw = PRIVSEP(getpwnamallow(user));
164 authctxt->user = xstrdup(user);
165 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
167 debug2("input_userauth_request: setting up authctxt for %s", user);
170 PRIVSEP(start_pam(authctxt));
173 logit("input_userauth_request: invalid user %s", user);
174 authctxt->pw = fakepw();
177 PRIVSEP(start_pam(authctxt));
179 #ifdef SSH_AUDIT_EVENTS
180 PRIVSEP(audit_event(SSH_INVALID_USER));
183 setproctitle("%s%s", authctxt->valid ? user : "unknown",
184 use_privsep ? " [net]" : "");
185 authctxt->service = xstrdup(service);
186 authctxt->style = style ? xstrdup(style) : NULL;
188 mm_inform_authserv(service, style);
189 } else if (strcmp(user, authctxt->user) != 0 ||
190 strcmp(service, authctxt->service) != 0) {
191 packet_disconnect("Change of username or service not allowed: "
192 "(%s,%s) -> (%s,%s)",
193 authctxt->user, authctxt->service, user, service);
196 #ifdef HAVE_LOGIN_CAP
197 if (authctxt->pw != NULL) {
198 lc = login_getpwclass(authctxt->pw);
200 lc = login_getclassbyname(NULL, authctxt->pw);
201 if (!auth_hostok(lc, from_host, from_ip)) {
202 logit("Denied connection for %.200s from %.200s [%.200s].",
203 authctxt->pw->pw_name, from_host, from_ip);
204 packet_disconnect("Sorry, you are not allowed to connect.");
206 if (!auth_timeok(lc, time(NULL))) {
207 logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
208 authctxt->pw->pw_name, from_host);
209 packet_disconnect("Logins not available right now.");
214 #endif /* HAVE_LOGIN_CAP */
217 auth2_challenge_stop(authctxt);
220 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
221 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
224 authctxt->postponed = 0;
226 /* try to authenticate user */
227 m = authmethod_lookup(method);
229 debug2("input_userauth_request: try method %s", method);
230 authenticated = m->userauth(authctxt);
232 userauth_finish(authctxt, authenticated, method);
240 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
244 if (!authctxt->valid && authenticated)
245 fatal("INTERNAL ERROR: authenticated invalid user %s",
248 /* Special handling for root */
249 if (authenticated && authctxt->pw->pw_uid == 0 &&
250 !auth_root_allowed(method)) {
252 #ifdef SSH_AUDIT_EVENTS
253 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
258 if (options.use_pam && authenticated) {
259 if (!PRIVSEP(do_pam_account())) {
260 /* if PAM returned a message, send it to the user */
261 if (buffer_len(&loginmsg) > 0) {
262 buffer_append(&loginmsg, "\0", 1);
263 userauth_send_banner(buffer_ptr(&loginmsg));
266 fatal("Access denied for user %s by PAM account "
267 "configuration", authctxt->user);
273 if (authenticated && cray_access_denied(authctxt->user)) {
275 fatal("Access denied for user %s.",authctxt->user);
279 /* Log before sending the reply */
280 auth_log(authctxt, authenticated, method, " ssh2");
282 if (authctxt->postponed)
285 /* XXX todo: check if multiple auth methods are needed */
286 if (authenticated == 1) {
287 /* turn off userauth */
288 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
289 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
292 /* now we can break out */
293 authctxt->success = 1;
295 if (authctxt->failures++ > options.max_authtries) {
296 #ifdef SSH_AUDIT_EVENTS
297 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
299 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
301 methods = authmethods_get();
302 packet_start(SSH2_MSG_USERAUTH_FAILURE);
303 packet_put_cstring(methods);
304 packet_put_char(0); /* XXX partial success, unused */
314 authmethods_get(void)
321 for (i = 0; authmethods[i] != NULL; i++) {
322 if (strcmp(authmethods[i]->name, "none") == 0)
324 if (authmethods[i]->enabled != NULL &&
325 *(authmethods[i]->enabled) != 0) {
326 if (buffer_len(&b) > 0)
327 buffer_append(&b, ",", 1);
328 buffer_append(&b, authmethods[i]->name,
329 strlen(authmethods[i]->name));
332 buffer_append(&b, "\0", 1);
333 list = xstrdup(buffer_ptr(&b));
339 authmethod_lookup(const char *name)
344 for (i = 0; authmethods[i] != NULL; i++)
345 if (authmethods[i]->enabled != NULL &&
346 *(authmethods[i]->enabled) != 0 &&
347 strcmp(name, authmethods[i]->name) == 0)
348 return authmethods[i];
349 debug2("Unrecognized authentication method name: %s",
350 name ? name : "NULL");