Import OpenSSH 5.0p1.
[dragonfly.git] / crypto / openssh-5 / auth2.c
CommitLineData
16c343f1
PA
1/* $OpenBSD: auth2.c,v 1.116 2007/09/29 00:25:51 dtucker Exp $ */
2/*
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
27
28#include <sys/types.h>
29
30#include <pwd.h>
31#include <stdarg.h>
32#include <string.h>
33
34#include "xmalloc.h"
35#include "ssh2.h"
36#include "packet.h"
37#include "log.h"
38#include "buffer.h"
39#include "servconf.h"
40#include "compat.h"
41#include "key.h"
42#include "hostfile.h"
43#include "auth.h"
44#include "dispatch.h"
45#include "pathnames.h"
46#include "buffer.h"
47
48#ifdef GSSAPI
49#include "ssh-gss.h"
50#endif
51#include "monitor_wrap.h"
52
53/* import */
54extern ServerOptions options;
55extern u_char *session_id2;
56extern u_int session_id2_len;
57extern Buffer loginmsg;
58
59/* methods */
60
61extern Authmethod method_none;
62extern Authmethod method_pubkey;
63extern Authmethod method_passwd;
64extern Authmethod method_kbdint;
65extern Authmethod method_hostbased;
66#ifdef GSSAPI
67extern Authmethod method_gssapi;
68#endif
69
70Authmethod *authmethods[] = {
71 &method_none,
72 &method_pubkey,
73#ifdef GSSAPI
74 &method_gssapi,
75#endif
76 &method_passwd,
77 &method_kbdint,
78 &method_hostbased,
79 NULL
80};
81
82/* protocol */
83
84static void input_service_request(int, u_int32_t, void *);
85static void input_userauth_request(int, u_int32_t, void *);
86
87/* helper */
88static Authmethod *authmethod_lookup(const char *);
89static char *authmethods_get(void);
90
91/*
92 * loop until authctxt->success == TRUE
93 */
94
95void
96do_authentication2(Authctxt *authctxt)
97{
98 dispatch_init(&dispatch_protocol_error);
99 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
100 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
101}
102
103/*ARGSUSED*/
104static void
105input_service_request(int type, u_int32_t seq, void *ctxt)
106{
107 Authctxt *authctxt = ctxt;
108 u_int len;
109 int acceptit = 0;
110 char *service = packet_get_string(&len);
111 packet_check_eom();
112
113 if (authctxt == NULL)
114 fatal("input_service_request: no authctxt");
115
116 if (strcmp(service, "ssh-userauth") == 0) {
117 if (!authctxt->success) {
118 acceptit = 1;
119 /* now we can handle user-auth requests */
120 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
121 }
122 }
123 /* XXX all other service requests are denied */
124
125 if (acceptit) {
126 packet_start(SSH2_MSG_SERVICE_ACCEPT);
127 packet_put_cstring(service);
128 packet_send();
129 packet_write_wait();
130 } else {
131 debug("bad service request %s", service);
132 packet_disconnect("bad service request %s", service);
133 }
134 xfree(service);
135}
136
137/*ARGSUSED*/
138static void
139input_userauth_request(int type, u_int32_t seq, void *ctxt)
140{
141 Authctxt *authctxt = ctxt;
142 Authmethod *m = NULL;
143 char *user, *service, *method, *style = NULL;
144 int authenticated = 0;
145
146 if (authctxt == NULL)
147 fatal("input_userauth_request: no authctxt");
148
149 user = packet_get_string(NULL);
150 service = packet_get_string(NULL);
151 method = packet_get_string(NULL);
152 debug("userauth-request for user %s service %s method %s", user, service, method);
153 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
154
155 if ((style = strchr(user, ':')) != NULL)
156 *style++ = 0;
157
158 if (authctxt->attempt++ == 0) {
159 /* setup auth context */
160 authctxt->pw = PRIVSEP(getpwnamallow(user));
161 authctxt->user = xstrdup(user);
162 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
163 authctxt->valid = 1;
164 debug2("input_userauth_request: setting up authctxt for %s", user);
165 } else {
166 logit("input_userauth_request: invalid user %s", user);
167 authctxt->pw = fakepw();
168#ifdef SSH_AUDIT_EVENTS
169 PRIVSEP(audit_event(SSH_INVALID_USER));
170#endif
171 }
172#ifdef USE_PAM
173 if (options.use_pam)
174 PRIVSEP(start_pam(authctxt));
175#endif
176 setproctitle("%s%s", authctxt->valid ? user : "unknown",
177 use_privsep ? " [net]" : "");
178 authctxt->service = xstrdup(service);
179 authctxt->style = style ? xstrdup(style) : NULL;
180 if (use_privsep)
181 mm_inform_authserv(service, style);
182 } else if (strcmp(user, authctxt->user) != 0 ||
183 strcmp(service, authctxt->service) != 0) {
184 packet_disconnect("Change of username or service not allowed: "
185 "(%s,%s) -> (%s,%s)",
186 authctxt->user, authctxt->service, user, service);
187 }
188 /* reset state */
189 auth2_challenge_stop(authctxt);
190
191#ifdef GSSAPI
192 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
193 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
194#endif
195
196 authctxt->postponed = 0;
197
198 /* try to authenticate user */
199 m = authmethod_lookup(method);
200 if (m != NULL) {
201 debug2("input_userauth_request: try method %s", method);
202 authenticated = m->userauth(authctxt);
203 }
204 userauth_finish(authctxt, authenticated, method);
205
206 xfree(service);
207 xfree(user);
208 xfree(method);
209}
210
211void
212userauth_finish(Authctxt *authctxt, int authenticated, char *method)
213{
214 char *methods;
215
216 if (!authctxt->valid && authenticated)
217 fatal("INTERNAL ERROR: authenticated invalid user %s",
218 authctxt->user);
219
220 /* Special handling for root */
221 if (authenticated && authctxt->pw->pw_uid == 0 &&
222 !auth_root_allowed(method)) {
223 authenticated = 0;
224#ifdef SSH_AUDIT_EVENTS
225 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
226#endif
227 }
228
229#ifdef USE_PAM
230 if (options.use_pam && authenticated) {
231 if (!PRIVSEP(do_pam_account())) {
232 /* if PAM returned a message, send it to the user */
233 if (buffer_len(&loginmsg) > 0) {
234 buffer_append(&loginmsg, "\0", 1);
235 userauth_send_banner(buffer_ptr(&loginmsg));
236 packet_write_wait();
237 }
238 fatal("Access denied for user %s by PAM account "
239 "configuration", authctxt->user);
240 }
241 }
242#endif
243
244#ifdef _UNICOS
245 if (authenticated && cray_access_denied(authctxt->user)) {
246 authenticated = 0;
247 fatal("Access denied for user %s.",authctxt->user);
248 }
249#endif /* _UNICOS */
250
251 /* Log before sending the reply */
252 auth_log(authctxt, authenticated, method, " ssh2");
253
254 if (authctxt->postponed)
255 return;
256
257 /* XXX todo: check if multiple auth methods are needed */
258 if (authenticated == 1) {
259 /* turn off userauth */
260 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
261 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
262 packet_send();
263 packet_write_wait();
264 /* now we can break out */
265 authctxt->success = 1;
266 } else {
267 if (authctxt->failures++ > options.max_authtries) {
268#ifdef SSH_AUDIT_EVENTS
269 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
270#endif
271 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
272 }
273 methods = authmethods_get();
274 packet_start(SSH2_MSG_USERAUTH_FAILURE);
275 packet_put_cstring(methods);
276 packet_put_char(0); /* XXX partial success, unused */
277 packet_send();
278 packet_write_wait();
279 xfree(methods);
280 }
281}
282
283static char *
284authmethods_get(void)
285{
286 Buffer b;
287 char *list;
288 int i;
289
290 buffer_init(&b);
291 for (i = 0; authmethods[i] != NULL; i++) {
292 if (strcmp(authmethods[i]->name, "none") == 0)
293 continue;
294 if (authmethods[i]->enabled != NULL &&
295 *(authmethods[i]->enabled) != 0) {
296 if (buffer_len(&b) > 0)
297 buffer_append(&b, ",", 1);
298 buffer_append(&b, authmethods[i]->name,
299 strlen(authmethods[i]->name));
300 }
301 }
302 buffer_append(&b, "\0", 1);
303 list = xstrdup(buffer_ptr(&b));
304 buffer_free(&b);
305 return list;
306}
307
308static Authmethod *
309authmethod_lookup(const char *name)
310{
311 int i;
312
313 if (name != NULL)
314 for (i = 0; authmethods[i] != NULL; i++)
315 if (authmethods[i]->enabled != NULL &&
316 *(authmethods[i]->enabled) != 0 &&
317 strcmp(name, authmethods[i]->name) == 0)
318 return authmethods[i];
319 debug2("Unrecognized authentication method name: %s",
320 name ? name : "NULL");
321 return NULL;
322}