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 1.96 2003/02/06 21:22:43 markus Exp $");
36 #include "pathnames.h"
37 #include "monitor_wrap.h"
44 extern ServerOptions options;
45 extern u_char *session_id2;
46 extern 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;
57 extern Authmethod method_external;
58 extern Authmethod method_gssapi;
60 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;
98 if (options.pam_authentication_via_kbd_int)
99 options.kbd_interactive_authentication = 1;
101 options.pam_authentication_via_kbd_int = 0;
103 dispatch_init(&dispatch_protocol_error);
104 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
105 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
111 input_service_request(int type, u_int32_t seq, void *ctxt)
113 Authctxt *authctxt = ctxt;
116 char *service = packet_get_string(&len);
119 if (authctxt == NULL)
120 fatal("input_service_request: no authctxt");
122 if (strcmp(service, "ssh-userauth") == 0) {
123 if (!authctxt->success) {
125 /* now we can handle user-auth requests */
126 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
129 /* XXX all other service requests are denied */
132 packet_start(SSH2_MSG_SERVICE_ACCEPT);
133 packet_put_cstring(service);
137 debug("bad service request %s", service);
138 packet_disconnect("bad service request %s", service);
144 input_userauth_request(int type, u_int32_t seq, void *ctxt)
146 Authctxt *authctxt = ctxt;
147 Authmethod *m = NULL;
148 char *user, *service, *method, *style = NULL;
149 int authenticated = 0;
151 if (authctxt == NULL)
152 fatal("input_userauth_request: no authctxt");
154 user = packet_get_string(NULL);
155 service = packet_get_string(NULL);
156 method = packet_get_string(NULL);
157 debug("userauth-request for user %s service %s method %s", user, service, method);
158 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
160 if ((style = strchr(user, ':')) != NULL)
163 if (authctxt->attempt++ == 0) {
164 /* setup auth context */
165 authctxt->pw = PRIVSEP(getpwnamallow(user));
166 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
168 debug2("input_userauth_request: setting up authctxt for %s", user);
170 PRIVSEP(start_pam(authctxt->pw->pw_name));
173 log("input_userauth_request: illegal user %s", user);
175 PRIVSEP(start_pam("NOUSER"));
178 setproctitle("%s%s", authctxt->pw ? user : "unknown",
179 use_privsep ? " [net]" : "");
180 authctxt->user = xstrdup(user);
181 authctxt->service = xstrdup(service);
182 authctxt->style = style ? xstrdup(style) : NULL;
184 mm_inform_authserv(service, style);
185 } else if (strcmp(user, authctxt->user) != 0 ||
186 strcmp(service, authctxt->service) != 0) {
187 packet_disconnect("Change of username or service not allowed: "
188 "(%s,%s) -> (%s,%s)",
189 authctxt->user, authctxt->service, user, service);
192 auth2_challenge_stop(authctxt);
195 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
196 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
199 authctxt->postponed = 0;
201 /* try to authenticate user */
202 m = authmethod_lookup(method);
204 debug2("input_userauth_request: try method %s", method);
205 authenticated = m->userauth(authctxt);
207 userauth_finish(authctxt, authenticated, method);
215 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
219 if (!authctxt->valid && authenticated)
220 fatal("INTERNAL ERROR: authenticated invalid user %s",
223 /* Special handling for root */
224 if (authenticated && authctxt->pw->pw_uid == 0 &&
225 !auth_root_allowed(method))
229 if (!use_privsep && authenticated && authctxt->user &&
230 !do_pam_account(authctxt->user, NULL))
235 if (authenticated && cray_access_denied(authctxt->user)) {
237 fatal("Access denied for user %s.",authctxt->user);
241 /* Log before sending the reply */
242 auth_log(authctxt, authenticated, method, " ssh2");
244 if (authctxt->postponed)
247 /* XXX todo: check if multiple auth methods are needed */
248 if (authenticated == 1) {
249 /* turn off userauth */
250 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
251 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
254 /* now we can break out */
255 authctxt->success = 1;
257 if (authctxt->failures++ > AUTH_FAIL_MAX) {
258 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
261 if (strcmp(method, "password") == 0)
262 cray_login_failure(authctxt->user, IA_UDBERR);
264 methods = authmethods_get();
265 packet_start(SSH2_MSG_USERAUTH_FAILURE);
266 packet_put_cstring(methods);
267 packet_put_char(0); /* XXX partial success, unused */
274 /* get current user */
279 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
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");