1 /* $OpenBSD: auth2.c,v 1.111 2006/07/06 16:03:53 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>
40 #include "pathnames.h"
41 #include "monitor_wrap.h"
49 extern ServerOptions options;
50 extern u_char *session_id2;
51 extern u_int session_id2_len;
52 extern Buffer loginmsg;
56 extern Authmethod method_none;
57 extern Authmethod method_pubkey;
58 extern Authmethod method_passwd;
59 extern Authmethod method_kbdint;
60 extern Authmethod method_hostbased;
62 extern Authmethod method_gssapi;
65 Authmethod *authmethods[] = {
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);
105 input_service_request(int type, u_int32_t seq, void *ctxt)
107 Authctxt *authctxt = ctxt;
110 char *service = packet_get_string(&len);
113 if (authctxt == NULL)
114 fatal("input_service_request: no authctxt");
116 if (strcmp(service, "ssh-userauth") == 0) {
117 if (!authctxt->success) {
119 /* now we can handle user-auth requests */
120 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
123 /* XXX all other service requests are denied */
126 packet_start(SSH2_MSG_SERVICE_ACCEPT);
127 packet_put_cstring(service);
131 debug("bad service request %s", service);
132 packet_disconnect("bad service request %s", service);
139 input_userauth_request(int type, u_int32_t seq, void *ctxt)
141 Authctxt *authctxt = ctxt;
142 Authmethod *m = NULL;
143 char *user, *service, *method, *style = NULL;
144 int authenticated = 0;
146 if (authctxt == NULL)
147 fatal("input_userauth_request: no authctxt");
149 user = packet_get_string(NULL);
150 service = packet_get_string(NULL);
151 method = packet_get_string(NULL);
152 debug("userauth-request for user %s service %s method %s", user, service, method);
153 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
155 if ((style = strchr(user, ':')) != NULL)
158 if (authctxt->attempt++ == 0) {
159 /* setup auth context */
160 authctxt->pw = PRIVSEP(getpwnamallow(user));
161 authctxt->user = xstrdup(user);
162 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
164 debug2("input_userauth_request: setting up authctxt for %s", user);
166 logit("input_userauth_request: invalid user %s", user);
167 authctxt->pw = fakepw();
168 #ifdef SSH_AUDIT_EVENTS
169 PRIVSEP(audit_event(SSH_INVALID_USER));
174 PRIVSEP(start_pam(authctxt));
176 setproctitle("%s%s", authctxt->valid ? user : "unknown",
177 use_privsep ? " [net]" : "");
178 authctxt->service = xstrdup(service);
179 authctxt->style = style ? xstrdup(style) : NULL;
181 mm_inform_authserv(service, style);
182 } else if (strcmp(user, authctxt->user) != 0 ||
183 strcmp(service, authctxt->service) != 0) {
184 packet_disconnect("Change of username or service not allowed: "
185 "(%s,%s) -> (%s,%s)",
186 authctxt->user, authctxt->service, user, service);
189 auth2_challenge_stop(authctxt);
192 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
193 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
196 authctxt->postponed = 0;
198 /* try to authenticate user */
199 m = authmethod_lookup(method);
201 debug2("input_userauth_request: try method %s", method);
202 authenticated = m->userauth(authctxt);
204 userauth_finish(authctxt, authenticated, method);
212 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
216 if (!authctxt->valid && authenticated)
217 fatal("INTERNAL ERROR: authenticated invalid user %s",
220 /* Special handling for root */
221 if (authenticated && authctxt->pw->pw_uid == 0 &&
222 !auth_root_allowed(method)) {
224 #ifdef SSH_AUDIT_EVENTS
225 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
230 if (options.use_pam && authenticated) {
231 if (!PRIVSEP(do_pam_account())) {
232 /* if PAM returned a message, send it to the user */
233 if (buffer_len(&loginmsg) > 0) {
234 buffer_append(&loginmsg, "\0", 1);
235 userauth_send_banner(buffer_ptr(&loginmsg));
238 fatal("Access denied for user %s by PAM account "
239 "configuration", authctxt->user);
245 if (authenticated && cray_access_denied(authctxt->user)) {
247 fatal("Access denied for user %s.",authctxt->user);
251 /* Log before sending the reply */
252 auth_log(authctxt, authenticated, method, " ssh2");
254 if (authctxt->postponed)
257 /* XXX todo: check if multiple auth methods are needed */
258 if (authenticated == 1) {
259 /* turn off userauth */
260 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
261 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
264 /* now we can break out */
265 authctxt->success = 1;
267 if (authctxt->failures++ > options.max_authtries) {
268 #ifdef SSH_AUDIT_EVENTS
269 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
271 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
273 methods = authmethods_get();
274 packet_start(SSH2_MSG_USERAUTH_FAILURE);
275 packet_put_cstring(methods);
276 packet_put_char(0); /* XXX partial success, unused */
286 authmethods_get(void)
293 for (i = 0; authmethods[i] != NULL; i++) {
294 if (strcmp(authmethods[i]->name, "none") == 0)
296 if (authmethods[i]->enabled != NULL &&
297 *(authmethods[i]->enabled) != 0) {
298 if (buffer_len(&b) > 0)
299 buffer_append(&b, ",", 1);
300 buffer_append(&b, authmethods[i]->name,
301 strlen(authmethods[i]->name));
304 buffer_append(&b, "\0", 1);
305 list = xstrdup(buffer_ptr(&b));
311 authmethod_lookup(const char *name)
316 for (i = 0; authmethods[i] != NULL; i++)
317 if (authmethods[i]->enabled != NULL &&
318 *(authmethods[i]->enabled) != 0 &&
319 strcmp(name, authmethods[i]->name) == 0)
320 return authmethods[i];
321 debug2("Unrecognized authentication method name: %s",
322 name ? name : "NULL");