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 1.93 2002/05/31 11:35:15 markus Exp $");
37 #include "pathnames.h"
38 #include "monitor_wrap.h"
45 extern ServerOptions options;
46 extern u_char *session_id2;
47 extern int session_id2_len;
49 Authctxt *x_authctxt = NULL;
53 extern Authmethod method_none;
55 extern Authmethod method_external;
56 extern Authmethod method_gssapi;
58 extern Authmethod method_pubkey;
59 extern Authmethod method_passwd;
60 extern Authmethod method_kbdint;
61 extern Authmethod method_hostbased;
63 Authmethod *authmethods[] = {
78 static void input_service_request(int, u_int32_t, void *);
79 static void input_userauth_request(int, u_int32_t, void *);
82 static Authmethod *authmethod_lookup(const char *);
83 static char *authmethods_get(void);
84 int user_key_allowed(struct passwd *, Key *);
85 int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
88 * loop until authctxt->success == TRUE
92 do_authentication2(void)
94 Authctxt *authctxt = authctxt_new();
96 x_authctxt = authctxt; /*XXX*/
98 /* challenge-response is implemented via keyboard interactive */
99 if (options.challenge_response_authentication)
100 options.kbd_interactive_authentication = 1;
101 if (options.pam_authentication_via_kbd_int)
102 options.kbd_interactive_authentication = 1;
104 options.pam_authentication_via_kbd_int = 0;
106 dispatch_init(&dispatch_protocol_error);
107 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
108 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
114 input_service_request(int type, u_int32_t seq, void *ctxt)
116 Authctxt *authctxt = ctxt;
119 char *service = packet_get_string(&len);
122 if (authctxt == NULL)
123 fatal("input_service_request: no authctxt");
125 if (strcmp(service, "ssh-userauth") == 0) {
126 if (!authctxt->success) {
128 /* now we can handle user-auth requests */
129 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
132 /* XXX all other service requests are denied */
135 packet_start(SSH2_MSG_SERVICE_ACCEPT);
136 packet_put_cstring(service);
140 debug("bad service request %s", service);
141 packet_disconnect("bad service request %s", service);
147 input_userauth_request(int type, u_int32_t seq, void *ctxt)
149 Authctxt *authctxt = ctxt;
150 Authmethod *m = NULL;
151 char *user, *service, *method, *style = NULL;
152 int authenticated = 0;
154 if (authctxt == NULL)
155 fatal("input_userauth_request: no authctxt");
157 user = packet_get_string(NULL);
158 service = packet_get_string(NULL);
159 method = packet_get_string(NULL);
162 if (strcmp(user, "") == 0) {
164 debug("gssapi received empty username");
165 PRIVSEP(ssh_gssapi_localname(&lname));
166 if (lname && lname[0] != '\0') {
169 debug("gssapi successfully set username to %s", user);
170 } else if (authctxt->valid) {
171 debug("failed to set username from gssapi context");
177 debug("userauth-request for user %s service %s method %s", user, service, method);
178 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
180 if ((style = strchr(user, ':')) != NULL)
183 if (!authctxt->user ||
184 strcmp(user, authctxt->user) != 0) {
185 /* setup auth context */
186 if (authctxt->user) {
187 xfree(authctxt->user);
188 authctxt->user = NULL;
190 if (authctxt->service) {
191 xfree(authctxt->service);
192 authctxt->service = NULL;
194 if (authctxt->style) {
195 xfree(authctxt->style);
196 authctxt->style = NULL;
198 authctxt->pw = PRIVSEP(getpwnamallow(user));
199 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
201 debug2("input_userauth_request: setting up authctxt for %s", user);
203 PRIVSEP(start_pam(authctxt->pw->pw_name));
207 log("input_userauth_request: illegal user %s", user);
209 PRIVSEP(start_pam("NOUSER"));
212 setproctitle("%s%s", authctxt->pw ? user : "unknown",
213 use_privsep ? " [net]" : "");
214 authctxt->user = xstrdup(user);
215 authctxt->service = xstrdup(service);
216 authctxt->style = style ? xstrdup(style) : NULL;
218 mm_inform_authserv(service, style);
221 auth2_challenge_stop(authctxt);
224 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
225 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
228 authctxt->postponed = 0;
230 /* try to authenticate user */
231 m = authmethod_lookup(method);
233 debug2("input_userauth_request: try method %s", method);
234 authenticated = m->userauth(authctxt);
237 userauth_finish(authctxt, authenticated, method);
245 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
249 if (!authctxt->valid && authenticated)
250 fatal("INTERNAL ERROR: authenticated invalid user %s",
253 /* Special handling for root */
254 if (authenticated && authctxt->pw->pw_uid == 0 &&
255 !auth_root_allowed(method))
259 if (!use_privsep && authenticated && authctxt->user &&
260 !do_pam_account(authctxt->user, NULL))
264 /* Log before sending the reply */
266 auth_log(authctxt, authenticated, method, " ssh1");
268 auth_log(authctxt, authenticated, method, " ssh2");
270 if (authctxt->postponed)
273 /* XXX todo: check if multiple auth methods are needed */
274 if (authenticated == 1) {
275 /* turn off userauth */
276 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
278 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
282 /* now we can break out */
283 authctxt->success = 1;
285 if (authctxt->failures++ > AUTH_FAIL_MAX) {
286 #ifdef WITH_AIXAUTHENTICATE
288 loginfailed(authctxt->user,
289 get_canonical_hostname(options.verify_reverse_mapping),
291 #endif /* WITH_AIXAUTHENTICATE */
292 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
296 * Break out of the dispatch loop now and go back to
297 * SSH1 code. We need to set the 'success' flag to
298 * break out of the loop. Set the 'postponed' flag to
299 * tell the SSH1 code that authentication failed. The
300 * SSH1 code will handle sending SSH_SMSG_FAILURE.
302 authctxt->success = authctxt->postponed = 1;
304 methods = authmethods_get();
305 packet_start(SSH2_MSG_USERAUTH_FAILURE);
306 packet_put_cstring(methods);
307 packet_put_char(0); /* XXX partial success, unused */
315 /* get current user */
320 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
326 authmethods_get(void)
333 for (i = 0; authmethods[i] != NULL; i++) {
334 if (strcmp(authmethods[i]->name, "none") == 0)
336 if (authmethods[i]->enabled != NULL &&
337 *(authmethods[i]->enabled) != 0) {
338 if (buffer_len(&b) > 0)
339 buffer_append(&b, ",", 1);
340 buffer_append(&b, authmethods[i]->name,
341 strlen(authmethods[i]->name));
344 buffer_append(&b, "\0", 1);
345 list = xstrdup(buffer_ptr(&b));
351 authmethod_lookup(const char *name)
356 for (i = 0; authmethods[i] != NULL; i++)
357 if (authmethods[i]->enabled != NULL &&
358 *(authmethods[i]->enabled) != 0 &&
359 strcmp(name, authmethods[i]->name) == 0)
360 return authmethods[i];
361 debug2("Unrecognized authentication method name: %s",
362 name ? name : "NULL");