1 /* $OpenBSD: auth2.c,v 1.115 2007/04/14 22:01:58 stevesk 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>
45 #include "pathnames.h"
52 #include "monitor_wrap.h"
55 extern ServerOptions options;
56 extern u_char *session_id2;
57 extern u_int session_id2_len;
58 extern Buffer loginmsg;
62 extern Authmethod method_none;
63 extern Authmethod method_pubkey;
64 extern Authmethod method_passwd;
65 extern Authmethod method_kbdint;
66 extern Authmethod method_hostbased;
68 extern Authmethod method_external;
69 extern Authmethod method_gsskeyex;
70 extern Authmethod method_gssapi;
71 extern Authmethod method_gssapi_compat;
74 static int log_flag = 0;
77 Authmethod *authmethods[] = {
84 &method_gssapi_compat,
94 static void input_service_request(int, u_int32_t, void *);
95 static void input_userauth_request(int, u_int32_t, void *);
98 static Authmethod *authmethod_lookup(const char *);
99 static char *authmethods_get(void);
100 int user_key_allowed(struct passwd *, Key *);
103 * loop until authctxt->success == TRUE
107 do_authentication2(Authctxt *authctxt)
109 dispatch_init(&dispatch_protocol_error);
110 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
111 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
116 input_service_request(int type, u_int32_t seq, void *ctxt)
118 Authctxt *authctxt = ctxt;
121 char *service = packet_get_string(&len);
124 if (authctxt == NULL)
125 fatal("input_service_request: no authctxt");
127 if (strcmp(service, "ssh-userauth") == 0) {
128 if (!authctxt->success) {
130 /* now we can handle user-auth requests */
131 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
134 /* XXX all other service requests are denied */
137 packet_start(SSH2_MSG_SERVICE_ACCEPT);
138 packet_put_cstring(service);
142 debug("bad service request %s", service);
143 packet_disconnect("bad service request %s", service);
150 input_userauth_request(int type, u_int32_t seq, void *ctxt)
152 Authctxt *authctxt = ctxt;
153 Authmethod *m = NULL;
154 char *user, *service, *method, *style = NULL;
155 int authenticated = 0;
157 if (authctxt == NULL)
158 fatal("input_userauth_request: no authctxt");
160 user = packet_get_string(NULL);
161 service = packet_get_string(NULL);
162 method = packet_get_string(NULL);
165 if (user[0] == '\0') {
166 debug("received empty username for %s", method);
167 if (strcmp(method, "external-keyx") == 0 ||
168 strcmp(method, "gssapi-keyex") == 0) {
170 PRIVSEP(ssh_gssapi_localname(&lname));
171 if (lname && lname[0] != '\0') {
174 debug("set username to %s from gssapi context", user);
176 debug("failed to set username from gssapi context");
177 packet_send_debug("failed to set username from gssapi context");
183 debug("userauth-request for user %s service %s method %s",
184 user[0] ? user : "<implicit>", service, method);
186 logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s",
187 get_remote_ipaddr(), get_remote_port(), user);
190 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
192 if ((style = strchr(user, ':')) != NULL)
195 /* If first time or username changed or empty username,
196 setup/reset authentication context. */
197 if ((authctxt->attempt++ == 0) ||
198 (strcmp(user, authctxt->user) != 0) ||
199 (strcmp(user, "") == 0)) {
200 if (authctxt->user) {
201 xfree(authctxt->user);
202 authctxt->user = NULL;
205 authctxt->user = xstrdup(user);
206 if (strcmp(service, "ssh-connection") != 0) {
207 packet_disconnect("Unsupported service %s", service);
210 /* If we're going to set the username based on the
211 GSSAPI context later, then wait until then to
212 verify it. Just put in placeholders for now. */
213 if ((strcmp(user, "") == 0) &&
214 ((strcmp(method, "gssapi") == 0) ||
215 (strcmp(method, "gssapi-with-mic") == 0))) {
216 authctxt->pw = fakepw();
219 authctxt->pw = PRIVSEP(getpwnamallow(user));
222 debug2("input_userauth_request: setting up authctxt for %s", user);
224 logit("input_userauth_request: invalid user %s", user);
225 authctxt->pw = fakepw();
226 #ifdef SSH_AUDIT_EVENTS
227 PRIVSEP(audit_event(SSH_INVALID_USER));
231 } /* endif for setting username based on GSSAPI context */
235 PRIVSEP(start_pam(authctxt));
237 setproctitle("%s%s", authctxt->valid ? user : "unknown",
238 use_privsep ? " [net]" : "");
239 if (authctxt->attempt == 1) {
240 authctxt->service = xstrdup(service);
241 authctxt->style = style ? xstrdup(style) : NULL;
243 mm_inform_authserv(service, style);
246 if (strcmp(service, authctxt->service) != 0) {
247 packet_disconnect("Change of service not allowed: "
248 "(%s,%s) -> (%s,%s)",
249 authctxt->user, authctxt->service, user, service);
252 auth2_challenge_stop(authctxt);
255 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
256 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
259 authctxt->postponed = 0;
260 authctxt->server_caused_failure = 0;
262 /* try to authenticate user */
263 m = authmethod_lookup(method);
265 debug2("input_userauth_request: try method %s", method);
266 authenticated = m->userauth(authctxt);
268 userauth_finish(authctxt, authenticated, method);
276 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
280 if (!authctxt->valid && authenticated)
281 fatal("INTERNAL ERROR: authenticated invalid user %s",
284 /* Special handling for root */
285 if (authenticated && authctxt->pw->pw_uid == 0 &&
286 !auth_root_allowed(method)) {
288 #ifdef SSH_AUDIT_EVENTS
289 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
294 if (options.use_pam && authenticated) {
295 if (!PRIVSEP(do_pam_account())) {
296 /* if PAM returned a message, send it to the user */
297 if (buffer_len(&loginmsg) > 0) {
298 buffer_append(&loginmsg, "\0", 1);
299 userauth_send_banner(buffer_ptr(&loginmsg));
302 fatal("Access denied for user %s by PAM account "
303 "configuration", authctxt->user);
309 if (authenticated && cray_access_denied(authctxt->user)) {
311 fatal("Access denied for user %s.",authctxt->user);
315 /* Log before sending the reply */
316 auth_log(authctxt, authenticated, method, " ssh2");
318 if (authctxt->postponed)
321 /* XXX todo: check if multiple auth methods are needed */
322 if (authenticated == 1) {
323 /* turn off userauth */
324 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
325 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
328 /* now we can break out */
329 authctxt->success = 1;
331 /* Dont count server configuration issues against the client */
332 if (!authctxt->server_caused_failure &&
333 authctxt->failures++ > options.max_authtries) {
334 #ifdef SSH_AUDIT_EVENTS
335 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
337 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
339 methods = authmethods_get();
340 packet_start(SSH2_MSG_USERAUTH_FAILURE);
341 packet_put_cstring(methods);
342 packet_put_char(0); /* XXX partial success, unused */
350 authmethods_get(void)
357 for (i = 0; authmethods[i] != NULL; i++) {
358 if (strcmp(authmethods[i]->name, "none") == 0)
360 if (authmethods[i]->enabled != NULL &&
361 *(authmethods[i]->enabled) != 0) {
362 if (buffer_len(&b) > 0)
363 buffer_append(&b, ",", 1);
364 buffer_append(&b, authmethods[i]->name,
365 strlen(authmethods[i]->name));
368 buffer_append(&b, "\0", 1);
369 list = xstrdup(buffer_ptr(&b));
375 authmethod_lookup(const char *name)
380 for (i = 0; authmethods[i] != NULL; i++)
381 if (authmethods[i]->enabled != NULL &&
382 *(authmethods[i]->enabled) != 0 &&
383 strcmp(name, authmethods[i]->name) == 0)
384 return authmethods[i];
385 debug2("Unrecognized authentication method name: %s",
386 name ? name : "NULL");