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_gssapi;
61 Authmethod *authmethods[] = {
75 static void input_service_request(int, u_int32_t, void *);
76 static void input_userauth_request(int, u_int32_t, void *);
79 static Authmethod *authmethod_lookup(const char *);
80 static char *authmethods_get(void);
81 int user_key_allowed(struct passwd *, Key *);
84 * loop until authctxt->success == TRUE
88 do_authentication2(Authctxt *authctxt)
90 /* challenge-response is implemented via keyboard interactive */
91 if (options.challenge_response_authentication)
92 options.kbd_interactive_authentication = 1;
94 dispatch_init(&dispatch_protocol_error);
95 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
96 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
100 input_service_request(int type, u_int32_t seq, void *ctxt)
102 Authctxt *authctxt = ctxt;
105 char *service = packet_get_string(&len);
108 if (authctxt == NULL)
109 fatal("input_service_request: no authctxt");
111 if (strcmp(service, "ssh-userauth") == 0) {
112 if (!authctxt->success) {
114 /* now we can handle user-auth requests */
115 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
118 /* XXX all other service requests are denied */
121 packet_start(SSH2_MSG_SERVICE_ACCEPT);
122 packet_put_cstring(service);
126 debug("bad service request %s", service);
127 packet_disconnect("bad service request %s", service);
133 input_userauth_request(int type, u_int32_t seq, void *ctxt)
135 Authctxt *authctxt = ctxt;
136 Authmethod *m = NULL;
137 char *user, *service, *method, *style = NULL;
138 int authenticated = 0;
140 if (authctxt == NULL)
141 fatal("input_userauth_request: no authctxt");
143 user = packet_get_string(NULL);
144 service = packet_get_string(NULL);
145 method = packet_get_string(NULL);
146 debug("userauth-request for user %s service %s method %s", user, service, method);
147 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
149 if ((style = strchr(user, ':')) != NULL)
152 if (authctxt->attempt++ == 0) {
153 /* setup auth context */
154 authctxt->pw = PRIVSEP(getpwnamallow(user));
155 authctxt->user = xstrdup(user);
156 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
158 debug2("input_userauth_request: setting up authctxt for %s", user);
160 logit("input_userauth_request: invalid user %s", user);
161 authctxt->pw = fakepw();
162 #ifdef SSH_AUDIT_EVENTS
163 PRIVSEP(audit_event(SSH_INVALID_USER));
168 PRIVSEP(start_pam(authctxt));
170 setproctitle("%s%s", authctxt->valid ? user : "unknown",
171 use_privsep ? " [net]" : "");
172 authctxt->service = xstrdup(service);
173 authctxt->style = style ? xstrdup(style) : NULL;
175 mm_inform_authserv(service, style);
176 } else if (strcmp(user, authctxt->user) != 0 ||
177 strcmp(service, authctxt->service) != 0) {
178 packet_disconnect("Change of username or service not allowed: "
179 "(%s,%s) -> (%s,%s)",
180 authctxt->user, authctxt->service, user, service);
183 auth2_challenge_stop(authctxt);
186 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
187 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
190 authctxt->postponed = 0;
192 /* try to authenticate user */
193 m = authmethod_lookup(method);
195 debug2("input_userauth_request: try method %s", method);
196 authenticated = m->userauth(authctxt);
198 userauth_finish(authctxt, authenticated, method);
206 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
210 if (!authctxt->valid && authenticated)
211 fatal("INTERNAL ERROR: authenticated invalid user %s",
214 /* Special handling for root */
215 if (authenticated && authctxt->pw->pw_uid == 0 &&
216 !auth_root_allowed(method)) {
218 #ifdef SSH_AUDIT_EVENTS
219 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
224 if (options.use_pam && authenticated) {
225 if (!PRIVSEP(do_pam_account())) {
226 /* if PAM returned a message, send it to the user */
227 if (buffer_len(&loginmsg) > 0) {
228 buffer_append(&loginmsg, "\0", 1);
229 userauth_send_banner(buffer_ptr(&loginmsg));
232 fatal("Access denied for user %s by PAM account "
233 "configuration", authctxt->user);
239 if (authenticated && cray_access_denied(authctxt->user)) {
241 fatal("Access denied for user %s.",authctxt->user);
245 /* Log before sending the reply */
246 auth_log(authctxt, authenticated, method, " ssh2");
248 if (authctxt->postponed)
251 /* XXX todo: check if multiple auth methods are needed */
252 if (authenticated == 1) {
253 /* turn off userauth */
254 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
255 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
258 /* now we can break out */
259 authctxt->success = 1;
261 if (authctxt->failures++ > options.max_authtries) {
262 #ifdef SSH_AUDIT_EVENTS
263 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
265 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
267 methods = authmethods_get();
268 packet_start(SSH2_MSG_USERAUTH_FAILURE);
269 packet_put_cstring(methods);
270 packet_put_char(0); /* XXX partial success, unused */
280 authmethods_get(void)
287 for (i = 0; authmethods[i] != NULL; i++) {
288 if (strcmp(authmethods[i]->name, "none") == 0)
290 if (authmethods[i]->enabled != NULL &&
291 *(authmethods[i]->enabled) != 0) {
292 if (buffer_len(&b) > 0)
293 buffer_append(&b, ",", 1);
294 buffer_append(&b, authmethods[i]->name,
295 strlen(authmethods[i]->name));
298 buffer_append(&b, "\0", 1);
299 list = xstrdup(buffer_ptr(&b));
305 authmethod_lookup(const char *name)
310 for (i = 0; authmethods[i] != NULL; i++)
311 if (authmethods[i]->enabled != NULL &&
312 *(authmethods[i]->enabled) != 0 &&
313 strcmp(name, authmethods[i]->name) == 0)
314 return authmethods[i];
315 debug2("Unrecognized authentication method name: %s",
316 name ? name : "NULL");