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 1.104 2003/11/04 08:54:09 djm Exp $");
35 #include "pathnames.h"
36 #include "monitor_wrap.h"
43 extern ServerOptions options;
44 extern u_char *session_id2;
45 extern u_int session_id2_len;
49 extern Authmethod method_none;
50 extern Authmethod method_pubkey;
51 extern Authmethod method_passwd;
52 extern Authmethod method_kbdint;
53 extern Authmethod method_hostbased;
55 extern Authmethod method_external;
56 extern Authmethod method_gssapi;
57 extern Authmethod method_gssapi_compat;
60 Authmethod *authmethods[] = {
66 &method_gssapi_compat,
76 static void input_service_request(int, u_int32_t, void *);
77 static void input_userauth_request(int, u_int32_t, void *);
80 static Authmethod *authmethod_lookup(const char *);
81 static char *authmethods_get(void);
82 int user_key_allowed(struct passwd *, Key *);
85 * loop until authctxt->success == TRUE
89 do_authentication2(Authctxt *authctxt)
91 /* challenge-response is implemented via keyboard interactive */
92 if (options.challenge_response_authentication)
93 options.kbd_interactive_authentication = 1;
95 dispatch_init(&dispatch_protocol_error);
96 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
97 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
101 input_service_request(int type, u_int32_t seq, void *ctxt)
103 Authctxt *authctxt = ctxt;
106 char *service = packet_get_string(&len);
109 if (authctxt == NULL)
110 fatal("input_service_request: no authctxt");
112 if (strcmp(service, "ssh-userauth") == 0) {
113 if (!authctxt->success) {
115 /* now we can handle user-auth requests */
116 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
119 /* XXX all other service requests are denied */
122 packet_start(SSH2_MSG_SERVICE_ACCEPT);
123 packet_put_cstring(service);
127 debug("bad service request %s", service);
128 packet_disconnect("bad service request %s", service);
134 input_userauth_request(int type, u_int32_t seq, void *ctxt)
136 Authctxt *authctxt = ctxt;
137 Authmethod *m = NULL;
138 char *user, *service, *method, *style = NULL;
139 int authenticated = 0;
141 if (authctxt == NULL)
142 fatal("input_userauth_request: no authctxt");
144 user = packet_get_string(NULL);
145 service = packet_get_string(NULL);
146 method = packet_get_string(NULL);
149 if (strcmp(user, "") == 0) {
150 debug("received empty username for %s", method);
151 if (strcmp(method, "external-keyx") == 0) {
153 PRIVSEP(ssh_gssapi_localname(&lname));
154 if (lname && lname[0] != '\0') {
157 debug("set username to %s from gssapi context", user);
158 } else if (authctxt->valid) {
159 debug("failed to set username from gssapi context");
165 debug("userauth-request for user %s service %s method %s",
166 (user && user[0]) ? user : "<implicit>", service, method);
167 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
169 if ((style = strchr(user, ':')) != NULL)
173 /* If first time or username changed or implicit username,
174 setup/reset authentication context. */
175 if ((authctxt->attempt++ == 0) ||
176 (strcmp(user, authctxt->user) != 0) ||
177 (strcmp(user, "") == 0)) {
178 /* setup auth context */
179 if (authctxt->user) {
180 xfree(authctxt->user);
181 authctxt->user = NULL;
183 if (authctxt->service) {
184 xfree(authctxt->service);
185 authctxt->service = NULL;
187 if (authctxt->style) {
188 xfree(authctxt->style);
189 authctxt->style = NULL;
192 /* We'll verify the username after we set it from the
194 if ((strcmp(user, "") == 0) &&
195 ((strcmp(method, "gssapi") == 0) ||
196 (strcmp(method, "external-keyx") == 0))) {
201 authctxt->pw = PRIVSEP(getpwnamallow(user));
202 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
204 debug2("input_userauth_request: setting up authctxt for %s", user);
207 PRIVSEP(start_pam(authctxt->pw->pw_name));
210 logit("input_userauth_request: illegal user %s", user);
211 authctxt->pw = fakepw();
214 PRIVSEP(start_pam(user));
220 setproctitle("%s%s", authctxt->pw ? user : "unknown",
221 use_privsep ? " [net]" : "");
222 authctxt->user = xstrdup(user);
223 authctxt->service = xstrdup(service);
224 authctxt->style = style ? xstrdup(style) : NULL;
225 if (use_privsep && (authctxt->attempt == 1))
226 mm_inform_authserv(service, style);
227 } else if (strcmp(service, authctxt->service) != 0) {
228 packet_disconnect("Change of service not allowed: "
229 "(%s,%s) -> (%s,%s)",
230 authctxt->user, authctxt->service, user, service);
233 auth2_challenge_stop(authctxt);
236 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
237 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
240 authctxt->postponed = 0;
242 /* try to authenticate user */
243 m = authmethod_lookup(method);
245 debug2("input_userauth_request: try method %s", method);
246 authenticated = m->userauth(authctxt);
248 userauth_finish(authctxt, authenticated, method);
256 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
260 if (!authctxt->valid && authenticated)
261 fatal("INTERNAL ERROR: authenticated invalid user %s",
264 /* Special handling for root */
265 if (authenticated && authctxt->pw->pw_uid == 0 &&
266 !auth_root_allowed(method))
270 if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
275 if (authenticated && cray_access_denied(authctxt->user)) {
277 fatal("Access denied for user %s.",authctxt->user);
281 /* Log before sending the reply */
282 auth_log(authctxt, authenticated, method, " ssh2");
284 if (authctxt->postponed)
287 /* XXX todo: check if multiple auth methods are needed */
288 if (authenticated == 1) {
289 /* turn off userauth */
290 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
291 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
294 /* now we can break out */
295 authctxt->success = 1;
297 if (authctxt->failures++ > AUTH_FAIL_MAX)
298 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
299 methods = authmethods_get();
300 packet_start(SSH2_MSG_USERAUTH_FAILURE);
301 packet_put_cstring(methods);
302 packet_put_char(0); /* XXX partial success, unused */
312 authmethods_get(void)
319 for (i = 0; authmethods[i] != NULL; i++) {
320 if (strcmp(authmethods[i]->name, "none") == 0)
322 if (authmethods[i]->enabled != NULL &&
323 *(authmethods[i]->enabled) != 0) {
324 if (buffer_len(&b) > 0)
325 buffer_append(&b, ",", 1);
326 buffer_append(&b, authmethods[i]->name,
327 strlen(authmethods[i]->name));
330 buffer_append(&b, "\0", 1);
331 list = xstrdup(buffer_ptr(&b));
337 authmethod_lookup(const char *name)
342 for (i = 0; authmethods[i] != NULL; i++)
343 if (authmethods[i]->enabled != NULL &&
344 *(authmethods[i]->enabled) != 0 &&
345 strcmp(name, authmethods[i]->name) == 0)
346 return authmethods[i];
347 debug2("Unrecognized authentication method name: %s",
348 name ? name : "NULL");