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"
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_gssapi;
70 Authmethod *authmethods[] = {
84 static void input_service_request(int, u_int32_t, void *);
85 static void input_userauth_request(int, u_int32_t, void *);
88 static Authmethod *authmethod_lookup(const char *);
89 static char *authmethods_get(void);
90 int user_key_allowed(struct passwd *, Key *);
93 * loop until authctxt->success == TRUE
97 do_authentication2(Authctxt *authctxt)
99 dispatch_init(&dispatch_protocol_error);
100 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
101 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
106 input_service_request(int type, u_int32_t seq, void *ctxt)
108 Authctxt *authctxt = ctxt;
111 char *service = packet_get_string(&len);
114 if (authctxt == NULL)
115 fatal("input_service_request: no authctxt");
117 if (strcmp(service, "ssh-userauth") == 0) {
118 if (!authctxt->success) {
120 /* now we can handle user-auth requests */
121 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
124 /* XXX all other service requests are denied */
127 packet_start(SSH2_MSG_SERVICE_ACCEPT);
128 packet_put_cstring(service);
132 debug("bad service request %s", service);
133 packet_disconnect("bad service request %s", service);
140 input_userauth_request(int type, u_int32_t seq, void *ctxt)
142 Authctxt *authctxt = ctxt;
143 Authmethod *m = NULL;
144 char *user, *service, *method, *style = NULL;
145 int authenticated = 0;
147 if (authctxt == NULL)
148 fatal("input_userauth_request: no authctxt");
150 user = packet_get_string(NULL);
151 service = packet_get_string(NULL);
152 method = packet_get_string(NULL);
153 debug("userauth-request for user %s service %s method %s", user, service, method);
154 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
156 if ((style = strchr(user, ':')) != NULL)
159 if (authctxt->attempt++ == 0) {
160 /* setup auth context */
161 authctxt->pw = PRIVSEP(getpwnamallow(user));
162 authctxt->user = xstrdup(user);
163 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
165 debug2("input_userauth_request: setting up authctxt for %s", user);
167 logit("input_userauth_request: invalid user %s", user);
168 authctxt->pw = fakepw();
169 #ifdef SSH_AUDIT_EVENTS
170 PRIVSEP(audit_event(SSH_INVALID_USER));
175 PRIVSEP(start_pam(authctxt));
177 setproctitle("%s%s", authctxt->valid ? user : "unknown",
178 use_privsep ? " [net]" : "");
179 authctxt->service = xstrdup(service);
180 authctxt->style = style ? xstrdup(style) : NULL;
182 mm_inform_authserv(service, style);
183 } else if (strcmp(user, authctxt->user) != 0 ||
184 strcmp(service, authctxt->service) != 0) {
185 packet_disconnect("Change of username or service not allowed: "
186 "(%s,%s) -> (%s,%s)",
187 authctxt->user, authctxt->service, user, service);
190 auth2_challenge_stop(authctxt);
193 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
194 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
197 authctxt->postponed = 0;
199 /* try to authenticate user */
200 m = authmethod_lookup(method);
202 debug2("input_userauth_request: try method %s", method);
203 authenticated = m->userauth(authctxt);
205 userauth_finish(authctxt, authenticated, method);
213 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
217 if (!authctxt->valid && authenticated)
218 fatal("INTERNAL ERROR: authenticated invalid user %s",
221 /* Special handling for root */
222 if (authenticated && authctxt->pw->pw_uid == 0 &&
223 !auth_root_allowed(method)) {
225 #ifdef SSH_AUDIT_EVENTS
226 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
231 if (options.use_pam && authenticated) {
232 if (!PRIVSEP(do_pam_account())) {
233 /* if PAM returned a message, send it to the user */
234 if (buffer_len(&loginmsg) > 0) {
235 buffer_append(&loginmsg, "\0", 1);
236 userauth_send_banner(buffer_ptr(&loginmsg));
239 fatal("Access denied for user %s by PAM account "
240 "configuration", authctxt->user);
246 if (authenticated && cray_access_denied(authctxt->user)) {
248 fatal("Access denied for user %s.",authctxt->user);
252 /* Log before sending the reply */
253 auth_log(authctxt, authenticated, method, " ssh2");
255 if (authctxt->postponed)
258 /* XXX todo: check if multiple auth methods are needed */
259 if (authenticated == 1) {
260 /* turn off userauth */
261 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
262 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
265 /* now we can break out */
266 authctxt->success = 1;
268 if (authctxt->failures++ > options.max_authtries) {
269 #ifdef SSH_AUDIT_EVENTS
270 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
272 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
274 methods = authmethods_get();
275 packet_start(SSH2_MSG_USERAUTH_FAILURE);
276 packet_put_cstring(methods);
277 packet_put_char(0); /* XXX partial success, unused */
285 authmethods_get(void)
292 for (i = 0; authmethods[i] != NULL; i++) {
293 if (strcmp(authmethods[i]->name, "none") == 0)
295 if (authmethods[i]->enabled != NULL &&
296 *(authmethods[i]->enabled) != 0) {
297 if (buffer_len(&b) > 0)
298 buffer_append(&b, ",", 1);
299 buffer_append(&b, authmethods[i]->name,
300 strlen(authmethods[i]->name));
303 buffer_append(&b, "\0", 1);
304 list = xstrdup(buffer_ptr(&b));
310 authmethod_lookup(const char *name)
315 for (i = 0; authmethods[i] != NULL; i++)
316 if (authmethods[i]->enabled != NULL &&
317 *(authmethods[i]->enabled) != 0 &&
318 strcmp(name, authmethods[i]->name) == 0)
319 return authmethods[i];
320 debug2("Unrecognized authentication method name: %s",
321 name ? name : "NULL");