1 /* $OpenBSD: auth2.c,v 1.114 2007/03/01 10:28:02 dtucker 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"
51 #include "monitor_wrap.h"
54 extern ServerOptions options;
55 extern u_char *session_id2;
56 extern u_int session_id2_len;
57 extern Buffer loginmsg;
61 extern Authmethod method_none;
62 extern Authmethod method_pubkey;
63 extern Authmethod method_passwd;
64 extern Authmethod method_kbdint;
65 extern Authmethod method_hostbased;
67 extern Authmethod method_gsskeyex;
68 extern Authmethod method_gssapi;
71 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 dispatch_init(&dispatch_protocol_error);
102 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
103 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
108 input_service_request(int type, u_int32_t seq, void *ctxt)
110 Authctxt *authctxt = ctxt;
113 char *service = packet_get_string(&len);
116 if (authctxt == NULL)
117 fatal("input_service_request: no authctxt");
119 if (strcmp(service, "ssh-userauth") == 0) {
120 if (!authctxt->success) {
122 /* now we can handle user-auth requests */
123 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
126 /* XXX all other service requests are denied */
129 packet_start(SSH2_MSG_SERVICE_ACCEPT);
130 packet_put_cstring(service);
134 debug("bad service request %s", service);
135 packet_disconnect("bad service request %s", service);
142 input_userauth_request(int type, u_int32_t seq, void *ctxt)
144 Authctxt *authctxt = ctxt;
145 Authmethod *m = NULL;
146 char *user, *service, *method, *style = NULL;
147 int authenticated = 0;
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);
169 logit("input_userauth_request: invalid user %s", user);
170 authctxt->pw = fakepw();
171 #ifdef SSH_AUDIT_EVENTS
172 PRIVSEP(audit_event(SSH_INVALID_USER));
177 PRIVSEP(start_pam(authctxt));
179 setproctitle("%s%s", authctxt->valid ? user : "unknown",
180 use_privsep ? " [net]" : "");
181 authctxt->service = xstrdup(service);
182 authctxt->style = style ? xstrdup(style) : NULL;
184 mm_inform_authserv(service, style);
185 } else if (strcmp(user, authctxt->user) != 0 ||
186 strcmp(service, authctxt->service) != 0) {
187 packet_disconnect("Change of username or service not allowed: "
188 "(%s,%s) -> (%s,%s)",
189 authctxt->user, authctxt->service, user, service);
192 auth2_challenge_stop(authctxt);
195 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
196 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
199 authctxt->postponed = 0;
200 authctxt->server_caused_failure = 0;
202 /* try to authenticate user */
203 m = authmethod_lookup(method);
205 debug2("input_userauth_request: try method %s", method);
206 authenticated = m->userauth(authctxt);
208 userauth_finish(authctxt, authenticated, method);
216 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
220 if (!authctxt->valid && authenticated)
221 fatal("INTERNAL ERROR: authenticated invalid user %s",
224 /* Special handling for root */
225 if (authenticated && authctxt->pw->pw_uid == 0 &&
226 !auth_root_allowed(method)) {
228 #ifdef SSH_AUDIT_EVENTS
229 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
234 if (options.use_pam && authenticated) {
235 if (!PRIVSEP(do_pam_account())) {
236 /* if PAM returned a message, send it to the user */
237 if (buffer_len(&loginmsg) > 0) {
238 buffer_append(&loginmsg, "\0", 1);
239 userauth_send_banner(buffer_ptr(&loginmsg));
242 fatal("Access denied for user %s by PAM account "
243 "configuration", authctxt->user);
249 if (authenticated && cray_access_denied(authctxt->user)) {
251 fatal("Access denied for user %s.",authctxt->user);
255 /* Log before sending the reply */
256 auth_log(authctxt, authenticated, method, " ssh2");
258 if (authctxt->postponed)
261 /* XXX todo: check if multiple auth methods are needed */
262 if (authenticated == 1) {
263 /* turn off userauth */
264 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
265 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
268 /* now we can break out */
269 authctxt->success = 1;
271 /* Dont count server configuration issues against the client */
272 if (!authctxt->server_caused_failure &&
273 authctxt->failures++ > options.max_authtries) {
274 #ifdef SSH_AUDIT_EVENTS
275 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
277 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
279 methods = authmethods_get();
280 packet_start(SSH2_MSG_USERAUTH_FAILURE);
281 packet_put_cstring(methods);
282 packet_put_char(0); /* XXX partial success, unused */
292 authmethods_get(void)
299 for (i = 0; authmethods[i] != NULL; i++) {
300 if (strcmp(authmethods[i]->name, "none") == 0)
302 if (authmethods[i]->enabled != NULL &&
303 *(authmethods[i]->enabled) != 0) {
304 if (buffer_len(&b) > 0)
305 buffer_append(&b, ",", 1);
306 buffer_append(&b, authmethods[i]->name,
307 strlen(authmethods[i]->name));
310 buffer_append(&b, "\0", 1);
311 list = xstrdup(buffer_ptr(&b));
317 authmethod_lookup(const char *name)
322 for (i = 0; authmethods[i] != NULL; i++)
323 if (authmethods[i]->enabled != NULL &&
324 *(authmethods[i]->enabled) != 0 &&
325 strcmp(name, authmethods[i]->name) == 0)
326 return authmethods[i];
327 debug2("Unrecognized authentication method name: %s",
328 name ? name : "NULL");