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"
44 extern ServerOptions options;
45 extern u_char *session_id2;
46 extern u_int session_id2_len;
50 extern Authmethod method_none;
51 extern Authmethod method_pubkey;
52 extern Authmethod method_passwd;
53 extern Authmethod method_kbdint;
54 extern Authmethod method_hostbased;
56 extern Authmethod method_external;
57 extern Authmethod method_gssapi;
58 extern Authmethod method_gssapi_compat;
61 Authmethod *authmethods[] = {
67 &method_gssapi_compat,
77 static void input_service_request(int, u_int32_t, void *);
78 static void input_userauth_request(int, u_int32_t, void *);
81 static Authmethod *authmethod_lookup(const char *);
82 static char *authmethods_get(void);
83 int user_key_allowed(struct passwd *, Key *);
86 * loop until authctxt->success == TRUE
90 do_authentication2(Authctxt *authctxt)
92 /* challenge-response is implemented via keyboard interactive */
93 if (options.challenge_response_authentication)
94 options.kbd_interactive_authentication = 1;
96 dispatch_init(&dispatch_protocol_error);
97 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
98 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
102 input_service_request(int type, u_int32_t seq, void *ctxt)
104 Authctxt *authctxt = ctxt;
107 char *service = packet_get_string(&len);
110 if (authctxt == NULL)
111 fatal("input_service_request: no authctxt");
113 if (strcmp(service, "ssh-userauth") == 0) {
114 if (!authctxt->success) {
116 /* now we can handle user-auth requests */
117 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
120 /* XXX all other service requests are denied */
123 packet_start(SSH2_MSG_SERVICE_ACCEPT);
124 packet_put_cstring(service);
128 debug("bad service request %s", service);
129 packet_disconnect("bad service request %s", service);
135 input_userauth_request(int type, u_int32_t seq, void *ctxt)
137 Authctxt *authctxt = ctxt;
138 Authmethod *m = NULL;
139 char *user, *service, *method, *style = NULL;
140 int authenticated = 0;
142 if (authctxt == NULL)
143 fatal("input_userauth_request: no authctxt");
145 user = packet_get_string(NULL);
146 service = packet_get_string(NULL);
147 method = packet_get_string(NULL);
150 if (user[0] == '\0') {
151 debug("received empty username for %s", method);
152 if (strcmp(method, "external-keyx") == 0) {
154 PRIVSEP(ssh_gssapi_localname(&lname));
155 if (lname && lname[0] != '\0') {
158 debug("set username to %s from gssapi context", user);
160 debug("failed to set username from gssapi context");
166 debug("userauth-request for user %s service %s method %s",
167 user[0] ? user : "<implicit>", service, method);
168 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
170 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 if (authctxt->user) {
179 xfree(authctxt->user);
180 authctxt->user = NULL;
184 /* If we're going to set the username based on the
185 GSSAPI context later, then wait until then to
186 verify it. Just put in placeholders for now. */
187 if ((strcmp(user, "") == 0) &&
188 ((strcmp(method, "gssapi") == 0) ||
189 (strcmp(method, "gssapi-with-mic") == 0))) {
190 authctxt->pw = fakepw();
191 authctxt->user = xstrdup(user);
194 authctxt->pw = PRIVSEP(getpwnamallow(user));
195 authctxt->user = xstrdup(user);
196 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
198 debug2("input_userauth_request: setting up authctxt for %s", user);
201 PRIVSEP(start_pam(authctxt));
204 logit("input_userauth_request: invalid user %s", user);
205 authctxt->pw = fakepw();
208 PRIVSEP(start_pam(authctxt));
212 } /* endif for setting username based on GSSAPI context */
214 setproctitle("%s%s", authctxt->valid ? user : "unknown",
215 use_privsep ? " [net]" : "");
216 if (authctxt->service == NULL) /* only set once */
217 authctxt->service = xstrdup(service);
218 if (authctxt->style == NULL) /* only set once */
219 authctxt->style = style ? xstrdup(style) : NULL;
220 if (use_privsep && (authctxt->attempt == 1))
221 mm_inform_authserv(service, style);
223 if (strcmp(service, authctxt->service) != 0) {
224 packet_disconnect("Change of service not allowed: "
225 "(%s,%s) -> (%s,%s)",
226 authctxt->user, authctxt->service, user, service);
229 auth2_challenge_stop(authctxt);
232 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
233 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
236 authctxt->postponed = 0;
238 /* try to authenticate user */
239 m = authmethod_lookup(method);
241 debug2("input_userauth_request: try method %s", method);
242 authenticated = m->userauth(authctxt);
244 userauth_finish(authctxt, authenticated, method);
252 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
256 if (!authctxt->valid && authenticated)
257 fatal("INTERNAL ERROR: authenticated invalid user %s",
260 /* Special handling for root */
261 if (authenticated && authctxt->pw->pw_uid == 0 &&
262 !auth_root_allowed(method))
266 if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
271 if (authenticated && cray_access_denied(authctxt->user)) {
273 fatal("Access denied for user %s.",authctxt->user);
277 /* Log before sending the reply */
278 auth_log(authctxt, authenticated, method, " ssh2");
280 if (authctxt->postponed)
283 /* XXX todo: check if multiple auth methods are needed */
284 if (authenticated == 1) {
285 /* turn off userauth */
286 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
287 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
290 /* now we can break out */
291 authctxt->success = 1;
293 if (authctxt->failures++ > options.max_authtries)
294 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
295 methods = authmethods_get();
296 packet_start(SSH2_MSG_USERAUTH_FAILURE);
297 packet_put_cstring(methods);
298 packet_put_char(0); /* XXX partial success, unused */
308 authmethods_get(void)
315 for (i = 0; authmethods[i] != NULL; i++) {
316 if (strcmp(authmethods[i]->name, "none") == 0)
318 if (authmethods[i]->enabled != NULL &&
319 *(authmethods[i]->enabled) != 0) {
320 if (buffer_len(&b) > 0)
321 buffer_append(&b, ",", 1);
322 buffer_append(&b, authmethods[i]->name,
323 strlen(authmethods[i]->name));
326 buffer_append(&b, "\0", 1);
327 list = xstrdup(buffer_ptr(&b));
333 authmethod_lookup(const char *name)
338 for (i = 0; authmethods[i] != NULL; i++)
339 if (authmethods[i]->enabled != NULL &&
340 *(authmethods[i]->enabled) != 0 &&
341 strcmp(name, authmethods[i]->name) == 0)
342 return authmethods[i];
343 debug2("Unrecognized authentication method name: %s",
344 name ? name : "NULL");