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 $");
36 #include "pathnames.h"
37 #include "monitor_wrap.h"
45 extern ServerOptions options;
46 extern u_char *session_id2;
47 extern u_int session_id2_len;
48 extern Buffer loginmsg;
52 extern Authmethod method_none;
53 extern Authmethod method_pubkey;
54 extern Authmethod method_passwd;
55 extern Authmethod method_kbdint;
56 extern Authmethod method_hostbased;
58 extern Authmethod method_external;
59 extern Authmethod method_gssapi;
60 extern Authmethod method_gssapi_compat;
63 Authmethod *authmethods[] = {
69 &method_gssapi_compat,
79 static void input_service_request(int, u_int32_t, void *);
80 static void input_userauth_request(int, u_int32_t, void *);
83 static Authmethod *authmethod_lookup(const char *);
84 static char *authmethods_get(void);
85 int user_key_allowed(struct passwd *, Key *);
88 * loop until authctxt->success == TRUE
92 do_authentication2(Authctxt *authctxt)
94 /* challenge-response is implemented via keyboard interactive */
95 if (options.challenge_response_authentication)
96 options.kbd_interactive_authentication = 1;
98 dispatch_init(&dispatch_protocol_error);
99 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
100 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
104 input_service_request(int type, u_int32_t seq, void *ctxt)
106 Authctxt *authctxt = ctxt;
109 char *service = packet_get_string(&len);
112 if (authctxt == NULL)
113 fatal("input_service_request: no authctxt");
115 if (strcmp(service, "ssh-userauth") == 0) {
116 if (!authctxt->success) {
118 /* now we can handle user-auth requests */
119 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
122 /* XXX all other service requests are denied */
125 packet_start(SSH2_MSG_SERVICE_ACCEPT);
126 packet_put_cstring(service);
130 debug("bad service request %s", service);
131 packet_disconnect("bad service request %s", service);
137 input_userauth_request(int type, u_int32_t seq, void *ctxt)
139 Authctxt *authctxt = ctxt;
140 Authmethod *m = NULL;
141 char *user, *service, *method, *style = NULL;
142 int authenticated = 0;
144 if (authctxt == NULL)
145 fatal("input_userauth_request: no authctxt");
147 user = packet_get_string(NULL);
148 service = packet_get_string(NULL);
149 method = packet_get_string(NULL);
152 if (user[0] == '\0') {
153 debug("received empty username for %s", method);
154 if (strcmp(method, "external-keyx") == 0) {
156 PRIVSEP(ssh_gssapi_localname(&lname));
157 if (lname && lname[0] != '\0') {
160 debug("set username to %s from gssapi context", user);
162 debug("failed to set username from gssapi context");
168 debug("userauth-request for user %s service %s method %s",
169 user[0] ? user : "<implicit>", service, method);
170 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
172 if ((style = strchr(user, ':')) != NULL)
175 /* If first time or username changed or implicit username,
176 setup/reset authentication context. */
177 if ((authctxt->attempt++ == 0) ||
178 (strcmp(user, authctxt->user) != 0) ||
179 (strcmp(user, "") == 0)) {
180 if (authctxt->user) {
181 xfree(authctxt->user);
182 authctxt->user = NULL;
186 /* If we're going to set the username based on the
187 GSSAPI context later, then wait until then to
188 verify it. Just put in placeholders for now. */
189 if ((strcmp(user, "") == 0) &&
190 ((strcmp(method, "gssapi") == 0) ||
191 (strcmp(method, "gssapi-with-mic") == 0))) {
192 authctxt->pw = fakepw();
193 authctxt->user = xstrdup(user);
196 authctxt->pw = PRIVSEP(getpwnamallow(user));
197 authctxt->user = xstrdup(user);
198 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
200 debug2("input_userauth_request: setting up authctxt for %s", user);
203 PRIVSEP(start_pam(authctxt));
206 logit("input_userauth_request: invalid user %s", user);
207 authctxt->pw = fakepw();
210 PRIVSEP(start_pam(authctxt));
212 #ifdef SSH_AUDIT_EVENTS
213 PRIVSEP(audit_event(SSH_INVALID_USER));
217 } /* endif for setting username based on GSSAPI context */
219 setproctitle("%s%s", authctxt->valid ? user : "unknown",
220 use_privsep ? " [net]" : "");
222 if (authctxt->attempt == 1) {
224 authctxt->service = xstrdup(service);
225 authctxt->style = style ? xstrdup(style) : NULL;
227 mm_inform_authserv(service, style);
229 } /* if (authctxt->attempt == 1) */
232 if (strcmp(service, authctxt->service) != 0) {
233 packet_disconnect("Change of service not allowed: "
234 "(%s,%s) -> (%s,%s)",
235 authctxt->user, authctxt->service, user, service);
238 auth2_challenge_stop(authctxt);
241 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
242 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
245 authctxt->postponed = 0;
247 /* try to authenticate user */
248 m = authmethod_lookup(method);
250 debug2("input_userauth_request: try method %s", method);
251 authenticated = m->userauth(authctxt);
253 userauth_finish(authctxt, authenticated, method);
261 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
265 if (!authctxt->valid && authenticated)
266 fatal("INTERNAL ERROR: authenticated invalid user %s",
269 /* Special handling for root */
270 if (authenticated && authctxt->pw->pw_uid == 0 &&
271 !auth_root_allowed(method)) {
273 #ifdef SSH_AUDIT_EVENTS
274 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
279 if (options.use_pam && authenticated) {
280 if (!PRIVSEP(do_pam_account())) {
281 /* if PAM returned a message, send it to the user */
282 if (buffer_len(&loginmsg) > 0) {
283 buffer_append(&loginmsg, "\0", 1);
284 userauth_send_banner(buffer_ptr(&loginmsg));
287 fatal("Access denied for user %s by PAM account "
288 "configuration", authctxt->user);
294 if (authenticated && cray_access_denied(authctxt->user)) {
296 fatal("Access denied for user %s.",authctxt->user);
300 /* Log before sending the reply */
301 auth_log(authctxt, authenticated, method, " ssh2");
303 if (authctxt->postponed)
306 /* XXX todo: check if multiple auth methods are needed */
307 if (authenticated == 1) {
308 /* turn off userauth */
309 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
310 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
313 /* now we can break out */
314 authctxt->success = 1;
316 if (authctxt->failures++ > options.max_authtries) {
317 #ifdef SSH_AUDIT_EVENTS
318 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
320 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
322 methods = authmethods_get();
323 packet_start(SSH2_MSG_USERAUTH_FAILURE);
324 packet_put_cstring(methods);
325 packet_put_char(0); /* XXX partial success, unused */
335 authmethods_get(void)
342 for (i = 0; authmethods[i] != NULL; i++) {
343 if (strcmp(authmethods[i]->name, "none") == 0)
345 if (authmethods[i]->enabled != NULL &&
346 *(authmethods[i]->enabled) != 0) {
347 if (buffer_len(&b) > 0)
348 buffer_append(&b, ",", 1);
349 buffer_append(&b, authmethods[i]->name,
350 strlen(authmethods[i]->name));
353 buffer_append(&b, "\0", 1);
354 list = xstrdup(buffer_ptr(&b));
360 authmethod_lookup(const char *name)
365 for (i = 0; authmethods[i] != NULL; i++)
366 if (authmethods[i]->enabled != NULL &&
367 *(authmethods[i]->enabled) != 0 &&
368 strcmp(name, authmethods[i]->name) == 0)
369 return authmethods[i];
370 debug2("Unrecognized authentication method name: %s",
371 name ? name : "NULL");