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 1.102 2003/08/26 09:58:43 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;
48 Authctxt *x_authctxt = NULL;
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 *);
82 int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
85 * loop until authctxt->success == TRUE
89 do_authentication2(void)
91 Authctxt *authctxt = authctxt_new();
93 x_authctxt = authctxt; /*XXX*/
95 /* challenge-response is implemented via keyboard interactive */
96 if (options.challenge_response_authentication)
97 options.kbd_interactive_authentication = 1;
99 dispatch_init(&dispatch_protocol_error);
100 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
101 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
107 input_service_request(int type, u_int32_t seq, void *ctxt)
109 Authctxt *authctxt = ctxt;
112 char *service = packet_get_string(&len);
115 if (authctxt == NULL)
116 fatal("input_service_request: no authctxt");
118 if (strcmp(service, "ssh-userauth") == 0) {
119 if (!authctxt->success) {
121 /* now we can handle user-auth requests */
122 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
125 /* XXX all other service requests are denied */
128 packet_start(SSH2_MSG_SERVICE_ACCEPT);
129 packet_put_cstring(service);
133 debug("bad service request %s", service);
134 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 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
164 debug2("input_userauth_request: setting up authctxt for %s", user);
167 PRIVSEP(start_pam(authctxt->pw->pw_name));
170 logit("input_userauth_request: illegal user %s", user);
171 authctxt->pw = fakepw();
174 PRIVSEP(start_pam(user));
177 setproctitle("%s%s", authctxt->pw ? user : "unknown",
178 use_privsep ? " [net]" : "");
179 authctxt->user = xstrdup(user);
180 authctxt->service = xstrdup(service);
181 authctxt->style = style ? xstrdup(style) : NULL;
183 mm_inform_authserv(service, style);
184 } else if (strcmp(user, authctxt->user) != 0 ||
185 strcmp(service, authctxt->service) != 0) {
186 packet_disconnect("Change of username or service not allowed: "
187 "(%s,%s) -> (%s,%s)",
188 authctxt->user, authctxt->service, user, service);
191 auth2_challenge_stop(authctxt);
194 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
195 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
198 authctxt->postponed = 0;
200 /* try to authenticate user */
201 m = authmethod_lookup(method);
203 debug2("input_userauth_request: try method %s", method);
204 authenticated = m->userauth(authctxt);
206 userauth_finish(authctxt, authenticated, method);
214 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
218 if (!authctxt->valid && authenticated)
219 fatal("INTERNAL ERROR: authenticated invalid user %s",
222 /* Special handling for root */
223 if (authenticated && authctxt->pw->pw_uid == 0 &&
224 !auth_root_allowed(method))
228 if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
233 if (authenticated && cray_access_denied(authctxt->user)) {
235 fatal("Access denied for user %s.",authctxt->user);
239 /* Log before sending the reply */
240 auth_log(authctxt, authenticated, method, " ssh2");
242 if (authctxt->postponed)
245 /* XXX todo: check if multiple auth methods are needed */
246 if (authenticated == 1) {
247 /* turn off userauth */
248 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
249 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
252 /* now we can break out */
253 authctxt->success = 1;
255 if (authctxt->failures++ > AUTH_FAIL_MAX)
256 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
257 methods = authmethods_get();
258 packet_start(SSH2_MSG_USERAUTH_FAILURE);
259 packet_put_cstring(methods);
260 packet_put_char(0); /* XXX partial success, unused */
267 /* get current user */
272 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
278 authmethods_get(void)
285 for (i = 0; authmethods[i] != NULL; i++) {
286 if (strcmp(authmethods[i]->name, "none") == 0)
288 if (authmethods[i]->enabled != NULL &&
289 *(authmethods[i]->enabled) != 0) {
290 if (buffer_len(&b) > 0)
291 buffer_append(&b, ",", 1);
292 buffer_append(&b, authmethods[i]->name,
293 strlen(authmethods[i]->name));
296 buffer_append(&b, "\0", 1);
297 list = xstrdup(buffer_ptr(&b));
303 authmethod_lookup(const char *name)
308 for (i = 0; authmethods[i] != NULL; i++)
309 if (authmethods[i]->enabled != NULL &&
310 *(authmethods[i]->enabled) != 0 &&
311 strcmp(name, authmethods[i]->name) == 0)
312 return authmethods[i];
313 debug2("Unrecognized authentication method name: %s",
314 name ? name : "NULL");