openssh/auth2.c: Add a missing include (canohost.h).
[dragonfly.git] / crypto / openssh / auth2.c
CommitLineData
40c002af 1/* $OpenBSD: auth2.c,v 1.121 2009/06/22 05:39:28 dtucker Exp $ */
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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>
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29#include <sys/stat.h>
30#include <sys/uio.h>
16c343f1 31
c8c467ee 32#include <fcntl.h>
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33#include <pwd.h>
34#include <stdarg.h>
35#include <string.h>
c8c467ee 36#include <unistd.h>
16c343f1 37
c8c467ee 38#include "atomicio.h"
40c002af 39#include "xmalloc.h"
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40#include "ssh2.h"
41#include "packet.h"
42#include "log.h"
43#include "buffer.h"
44#include "servconf.h"
45#include "compat.h"
46#include "key.h"
47#include "hostfile.h"
48#include "auth.h"
49#include "dispatch.h"
50#include "pathnames.h"
51#include "buffer.h"
7835af9a 52#include "canohost.h"
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53
54#ifdef GSSAPI
55#include "ssh-gss.h"
56#endif
57#include "monitor_wrap.h"
58
59/* import */
60extern ServerOptions options;
61extern u_char *session_id2;
62extern u_int session_id2_len;
63extern Buffer loginmsg;
64
65/* methods */
66
67extern Authmethod method_none;
68extern Authmethod method_pubkey;
69extern Authmethod method_passwd;
70extern Authmethod method_kbdint;
71extern Authmethod method_hostbased;
72#ifdef GSSAPI
73extern Authmethod method_gssapi;
74#endif
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75#ifdef JPAKE
76extern Authmethod method_jpake;
77#endif
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78
79Authmethod *authmethods[] = {
80 &method_none,
81 &method_pubkey,
82#ifdef GSSAPI
83 &method_gssapi,
84#endif
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85#ifdef JPAKE
86 &method_jpake,
87#endif
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88 &method_passwd,
89 &method_kbdint,
90 &method_hostbased,
91 NULL
92};
93
94/* protocol */
95
96static void input_service_request(int, u_int32_t, void *);
97static void input_userauth_request(int, u_int32_t, void *);
98
99/* helper */
100static Authmethod *authmethod_lookup(const char *);
101static char *authmethods_get(void);
102
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103char *
104auth2_read_banner(void)
105{
106 struct stat st;
107 char *banner = NULL;
108 size_t len, n;
109 int fd;
110
111 if ((fd = open(options.banner, O_RDONLY)) == -1)
112 return (NULL);
113 if (fstat(fd, &st) == -1) {
114 close(fd);
115 return (NULL);
116 }
117 if (st.st_size > 1*1024*1024) {
118 close(fd);
119 return (NULL);
120 }
121
122 len = (size_t)st.st_size; /* truncate */
123 banner = xmalloc(len + 1);
124 n = atomicio(read, fd, banner, len);
125 close(fd);
126
127 if (n != len) {
128 xfree(banner);
129 return (NULL);
130 }
131 banner[n] = '\0';
132
133 return (banner);
134}
135
136void
137userauth_send_banner(const char *msg)
138{
139 if (datafellows & SSH_BUG_BANNER)
140 return;
141
142 packet_start(SSH2_MSG_USERAUTH_BANNER);
143 packet_put_cstring(msg);
144 packet_put_cstring(""); /* language, unused */
145 packet_send();
146 debug("%s: sent", __func__);
147}
148
149static void
150userauth_banner(void)
151{
152 char *banner = NULL;
153
154 if (options.banner == NULL ||
155 strcasecmp(options.banner, "none") == 0 ||
156 (datafellows & SSH_BUG_BANNER) != 0)
157 return;
158
159 if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
160 goto done;
161 userauth_send_banner(banner);
162
163done:
164 if (banner)
165 xfree(banner);
166}
167
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168/*
169 * loop until authctxt->success == TRUE
170 */
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171void
172do_authentication2(Authctxt *authctxt)
173{
174 dispatch_init(&dispatch_protocol_error);
175 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
176 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
177}
178
179/*ARGSUSED*/
180static void
181input_service_request(int type, u_int32_t seq, void *ctxt)
182{
183 Authctxt *authctxt = ctxt;
184 u_int len;
185 int acceptit = 0;
186 char *service = packet_get_string(&len);
187 packet_check_eom();
188
189 if (authctxt == NULL)
190 fatal("input_service_request: no authctxt");
191
192 if (strcmp(service, "ssh-userauth") == 0) {
193 if (!authctxt->success) {
194 acceptit = 1;
195 /* now we can handle user-auth requests */
196 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
197 }
198 }
199 /* XXX all other service requests are denied */
200
201 if (acceptit) {
202 packet_start(SSH2_MSG_SERVICE_ACCEPT);
203 packet_put_cstring(service);
204 packet_send();
205 packet_write_wait();
206 } else {
207 debug("bad service request %s", service);
208 packet_disconnect("bad service request %s", service);
209 }
210 xfree(service);
211}
212
213/*ARGSUSED*/
214static void
215input_userauth_request(int type, u_int32_t seq, void *ctxt)
216{
217 Authctxt *authctxt = ctxt;
218 Authmethod *m = NULL;
219 char *user, *service, *method, *style = NULL;
220 int authenticated = 0;
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221#ifdef HAVE_LOGIN_CAP
222 login_cap_t *lc;
223 const char *from_host, *from_ip;
224
225 from_host = get_canonical_hostname(options.use_dns);
226 from_ip = get_remote_ipaddr();
227#endif
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228
229 if (authctxt == NULL)
230 fatal("input_userauth_request: no authctxt");
231
232 user = packet_get_string(NULL);
233 service = packet_get_string(NULL);
234 method = packet_get_string(NULL);
235 debug("userauth-request for user %s service %s method %s", user, service, method);
236 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
237
238 if ((style = strchr(user, ':')) != NULL)
239 *style++ = 0;
240
241 if (authctxt->attempt++ == 0) {
242 /* setup auth context */
243 authctxt->pw = PRIVSEP(getpwnamallow(user));
244 authctxt->user = xstrdup(user);
245 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
246 authctxt->valid = 1;
247 debug2("input_userauth_request: setting up authctxt for %s", user);
248 } else {
249 logit("input_userauth_request: invalid user %s", user);
250 authctxt->pw = fakepw();
251#ifdef SSH_AUDIT_EVENTS
252 PRIVSEP(audit_event(SSH_INVALID_USER));
253#endif
254 }
255#ifdef USE_PAM
256 if (options.use_pam)
257 PRIVSEP(start_pam(authctxt));
258#endif
259 setproctitle("%s%s", authctxt->valid ? user : "unknown",
260 use_privsep ? " [net]" : "");
261 authctxt->service = xstrdup(service);
262 authctxt->style = style ? xstrdup(style) : NULL;
263 if (use_privsep)
264 mm_inform_authserv(service, style);
c8c467ee 265 userauth_banner();
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266 } else if (strcmp(user, authctxt->user) != 0 ||
267 strcmp(service, authctxt->service) != 0) {
268 packet_disconnect("Change of username or service not allowed: "
269 "(%s,%s) -> (%s,%s)",
270 authctxt->user, authctxt->service, user, service);
271 }
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272
273#ifdef HAVE_LOGIN_CAP
274 if (authctxt->pw != NULL) {
275 lc = login_getpwclass(authctxt->pw);
276 if (lc == NULL)
277 lc = login_getclassbyname(NULL, authctxt->pw);
278 if (!auth_hostok(lc, from_host, from_ip)) {
279 logit("Denied connection for %.200s from %.200s [%.200s].",
280 authctxt->pw->pw_name, from_host, from_ip);
281 packet_disconnect("Sorry, you are not allowed to connect.");
282 }
283 if (!auth_timeok(lc, time(NULL))) {
284 logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
285 authctxt->pw->pw_name, from_host);
286 packet_disconnect("Logins not available right now.");
287 }
288 login_close(lc);
289 lc = NULL;
290 }
291#endif /* HAVE_LOGIN_CAP */
292
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293 /* reset state */
294 auth2_challenge_stop(authctxt);
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295#ifdef JPAKE
296 auth2_jpake_stop(authctxt);
297#endif
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298
299#ifdef GSSAPI
cb5eb4f1 300 /* XXX move to auth2_gssapi_stop() */
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301 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
302 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
303#endif
304
305 authctxt->postponed = 0;
306
307 /* try to authenticate user */
308 m = authmethod_lookup(method);
c8c467ee 309 if (m != NULL && authctxt->failures < options.max_authtries) {
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310 debug2("input_userauth_request: try method %s", method);
311 authenticated = m->userauth(authctxt);
312 }
313 userauth_finish(authctxt, authenticated, method);
314
315 xfree(service);
316 xfree(user);
317 xfree(method);
318}
319
320void
321userauth_finish(Authctxt *authctxt, int authenticated, char *method)
322{
323 char *methods;
324
325 if (!authctxt->valid && authenticated)
326 fatal("INTERNAL ERROR: authenticated invalid user %s",
327 authctxt->user);
328
329 /* Special handling for root */
330 if (authenticated && authctxt->pw->pw_uid == 0 &&
331 !auth_root_allowed(method)) {
332 authenticated = 0;
333#ifdef SSH_AUDIT_EVENTS
334 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
335#endif
336 }
337
338#ifdef USE_PAM
339 if (options.use_pam && authenticated) {
340 if (!PRIVSEP(do_pam_account())) {
341 /* if PAM returned a message, send it to the user */
342 if (buffer_len(&loginmsg) > 0) {
343 buffer_append(&loginmsg, "\0", 1);
344 userauth_send_banner(buffer_ptr(&loginmsg));
345 packet_write_wait();
346 }
347 fatal("Access denied for user %s by PAM account "
348 "configuration", authctxt->user);
349 }
350 }
351#endif
352
353#ifdef _UNICOS
354 if (authenticated && cray_access_denied(authctxt->user)) {
355 authenticated = 0;
356 fatal("Access denied for user %s.",authctxt->user);
357 }
358#endif /* _UNICOS */
359
360 /* Log before sending the reply */
361 auth_log(authctxt, authenticated, method, " ssh2");
362
363 if (authctxt->postponed)
364 return;
365
366 /* XXX todo: check if multiple auth methods are needed */
367 if (authenticated == 1) {
368 /* turn off userauth */
369 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
370 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
371 packet_send();
372 packet_write_wait();
373 /* now we can break out */
374 authctxt->success = 1;
375 } else {
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376
377 /* Allow initial try of "none" auth without failure penalty */
378 if (authctxt->attempt > 1 || strcmp(method, "none") != 0)
379 authctxt->failures++;
380 if (authctxt->failures >= options.max_authtries) {
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381#ifdef SSH_AUDIT_EVENTS
382 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
383#endif
384 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
385 }
386 methods = authmethods_get();
387 packet_start(SSH2_MSG_USERAUTH_FAILURE);
388 packet_put_cstring(methods);
389 packet_put_char(0); /* XXX partial success, unused */
390 packet_send();
391 packet_write_wait();
392 xfree(methods);
393 }
394}
395
396static char *
397authmethods_get(void)
398{
399 Buffer b;
400 char *list;
401 int i;
402
403 buffer_init(&b);
404 for (i = 0; authmethods[i] != NULL; i++) {
405 if (strcmp(authmethods[i]->name, "none") == 0)
406 continue;
407 if (authmethods[i]->enabled != NULL &&
408 *(authmethods[i]->enabled) != 0) {
409 if (buffer_len(&b) > 0)
410 buffer_append(&b, ",", 1);
411 buffer_append(&b, authmethods[i]->name,
412 strlen(authmethods[i]->name));
413 }
414 }
415 buffer_append(&b, "\0", 1);
416 list = xstrdup(buffer_ptr(&b));
417 buffer_free(&b);
418 return list;
419}
420
421static Authmethod *
422authmethod_lookup(const char *name)
423{
424 int i;
425
426 if (name != NULL)
427 for (i = 0; authmethods[i] != NULL; i++)
428 if (authmethods[i]->enabled != NULL &&
429 *(authmethods[i]->enabled) != 0 &&
430 strcmp(name, authmethods[i]->name) == 0)
431 return authmethods[i];
432 debug2("Unrecognized authentication method name: %s",
433 name ? name : "NULL");
434 return NULL;
435}
c8c467ee 436