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 1.95 2002/08/22 21:33:58 markus Exp $");
36 #include "pathnames.h"
37 #include "monitor_wrap.h"
40 extern ServerOptions options;
41 extern u_char *session_id2;
42 extern int session_id2_len;
44 Authctxt *x_authctxt = NULL;
48 extern Authmethod method_none;
49 extern Authmethod method_pubkey;
50 extern Authmethod method_passwd;
51 extern Authmethod method_kbdint;
52 extern Authmethod method_hostbased;
54 Authmethod *authmethods[] = {
65 static void input_service_request(int, u_int32_t, void *);
66 static void input_userauth_request(int, u_int32_t, void *);
69 static Authmethod *authmethod_lookup(const char *);
70 static char *authmethods_get(void);
71 int user_key_allowed(struct passwd *, Key *);
72 int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
75 * loop until authctxt->success == TRUE
79 do_authentication2(void)
81 Authctxt *authctxt = authctxt_new();
83 x_authctxt = authctxt; /*XXX*/
85 /* challenge-response is implemented via keyboard interactive */
86 if (options.challenge_response_authentication)
87 options.kbd_interactive_authentication = 1;
88 if (options.pam_authentication_via_kbd_int)
89 options.kbd_interactive_authentication = 1;
91 options.pam_authentication_via_kbd_int = 0;
93 dispatch_init(&dispatch_protocol_error);
94 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
95 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);
147 debug("userauth-request for user %s service %s method %s", user, service, method);
148 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
150 if ((style = strchr(user, ':')) != NULL)
153 if (authctxt->attempt++ == 0) {
154 /* setup auth context */
155 authctxt->pw = PRIVSEP(getpwnamallow(user));
156 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
158 debug2("input_userauth_request: setting up authctxt for %s", user);
160 PRIVSEP(start_pam(authctxt->pw->pw_name));
163 log("input_userauth_request: illegal user %s", user);
165 PRIVSEP(start_pam("NOUSER"));
168 setproctitle("%s%s", authctxt->pw ? user : "unknown",
169 use_privsep ? " [net]" : "");
170 authctxt->user = xstrdup(user);
171 authctxt->service = xstrdup(service);
172 authctxt->style = style ? xstrdup(style) : NULL;
174 mm_inform_authserv(service, style);
175 } else if (strcmp(user, authctxt->user) != 0 ||
176 strcmp(service, authctxt->service) != 0) {
177 packet_disconnect("Change of username or service not allowed: "
178 "(%s,%s) -> (%s,%s)",
179 authctxt->user, authctxt->service, user, service);
182 auth2_challenge_stop(authctxt);
183 authctxt->postponed = 0;
185 /* try to authenticate user */
186 m = authmethod_lookup(method);
188 debug2("input_userauth_request: try method %s", method);
189 authenticated = m->userauth(authctxt);
191 userauth_finish(authctxt, authenticated, method);
199 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
203 if (!authctxt->valid && authenticated)
204 fatal("INTERNAL ERROR: authenticated invalid user %s",
207 /* Special handling for root */
209 authenticated && authctxt->pw->pw_uid == 0 &&
210 !auth_root_allowed(method))
214 if (!use_privsep && authenticated && authctxt->user &&
215 !do_pam_account(authctxt->user, NULL))
219 /* Log before sending the reply */
220 auth_log(authctxt, authenticated, method, " ssh2");
222 if (authctxt->postponed)
225 /* XXX todo: check if multiple auth methods are needed */
226 if (authenticated == 1) {
227 /* turn off userauth */
228 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
229 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
232 /* now we can break out */
233 authctxt->success = 1;
235 if (authctxt->failures++ > AUTH_FAIL_MAX) {
236 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
238 methods = authmethods_get();
239 packet_start(SSH2_MSG_USERAUTH_FAILURE);
240 packet_put_cstring(methods);
241 packet_put_char(0); /* XXX partial success, unused */
248 /* get current user */
253 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
259 authmethods_get(void)
266 for (i = 0; authmethods[i] != NULL; i++) {
267 if (strcmp(authmethods[i]->name, "none") == 0)
269 if (authmethods[i]->enabled != NULL &&
270 *(authmethods[i]->enabled) != 0) {
271 if (buffer_len(&b) > 0)
272 buffer_append(&b, ",", 1);
273 buffer_append(&b, authmethods[i]->name,
274 strlen(authmethods[i]->name));
277 buffer_append(&b, "\0", 1);
278 list = xstrdup(buffer_ptr(&b));
284 authmethod_lookup(const char *name)
289 for (i = 0; authmethods[i] != NULL; i++)
290 if (authmethods[i]->enabled != NULL &&
291 *(authmethods[i]->enabled) != 0 &&
292 strcmp(name, authmethods[i]->name) == 0)
293 return authmethods[i];
294 debug2("Unrecognized authentication method name: %s",
295 name ? name : "NULL");