]> andersk Git - openssh.git/blame - auth2.c
- markus@cvs.openbsd.org 2001/12/27 20:39:58
[openssh.git] / auth2.c
CommitLineData
a306f2dd 1/*
2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
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.
a306f2dd 12 *
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.
23 */
bcbf86ec 24
a306f2dd 25#include "includes.h"
24ca6821 26RCSID("$OpenBSD: auth2.c,v 1.78 2001/12/20 22:50:24 djm Exp $");
94ec8c6b 27
a306f2dd 28#include <openssl/evp.h>
29
42f11eb2 30#include "ssh2.h"
a306f2dd 31#include "xmalloc.h"
32#include "rsa.h"
1729c161 33#include "sshpty.h"
a306f2dd 34#include "packet.h"
35#include "buffer.h"
42f11eb2 36#include "log.h"
a306f2dd 37#include "servconf.h"
38#include "compat.h"
a5efa1bb 39#include "channels.h"
a306f2dd 40#include "bufaux.h"
a306f2dd 41#include "auth.h"
42#include "session.h"
43#include "dispatch.h"
a306f2dd 44#include "key.h"
b0e305c9 45#include "cipher.h"
a306f2dd 46#include "kex.h"
42f11eb2 47#include "pathnames.h"
a306f2dd 48#include "uidswap.h"
38c295d6 49#include "auth-options.h"
3b1a83df 50#include "misc.h"
8002af61 51#include "hostfile.h"
52#include "canohost.h"
5ba55ada 53#include "match.h"
a306f2dd 54
55/* import */
56extern ServerOptions options;
1e3b8b07 57extern u_char *session_id2;
a306f2dd 58extern int session_id2_len;
59
94ec8c6b 60static Authctxt *x_authctxt = NULL;
61static int one = 1;
62
63typedef struct Authmethod Authmethod;
64struct Authmethod {
65 char *name;
66 int (*userauth)(Authctxt *authctxt);
67 int *enabled;
68};
69
a306f2dd 70/* protocol */
71
24ca6821 72static void input_service_request(int, int, u_int32_t, void *);
73static void input_userauth_request(int, int, u_int32_t, void *);
74static void protocol_error(int, int, u_int32_t, void *);
a306f2dd 75
a306f2dd 76/* helper */
396c147e 77static Authmethod *authmethod_lookup(const char *);
ffb215be 78static char *authmethods_get(void);
396c147e 79static int user_key_allowed(struct passwd *, Key *);
80static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
a306f2dd 81
94ec8c6b 82/* auth */
396c147e 83static void userauth_banner(void);
84static int userauth_none(Authctxt *);
85static int userauth_passwd(Authctxt *);
86static int userauth_pubkey(Authctxt *);
87static int userauth_hostbased(Authctxt *);
88static int userauth_kbdint(Authctxt *);
94ec8c6b 89
90Authmethod authmethods[] = {
91 {"none",
92 userauth_none,
93 &one},
94 {"publickey",
95 userauth_pubkey,
fa08c86b 96 &options.pubkey_authentication},
94ec8c6b 97 {"password",
98 userauth_passwd,
99 &options.password_authentication},
c845316f 100 {"keyboard-interactive",
101 userauth_kbdint,
102 &options.kbd_interactive_authentication},
8002af61 103 {"hostbased",
104 userauth_hostbased,
105 &options.hostbased_authentication},
94ec8c6b 106 {NULL, NULL, NULL}
a306f2dd 107};
a306f2dd 108
109/*
94ec8c6b 110 * loop until authctxt->success == TRUE
a306f2dd 111 */
112
113void
d5bb9418 114do_authentication2(void)
a306f2dd 115{
59c97189 116 Authctxt *authctxt = authctxt_new();
117
94ec8c6b 118 x_authctxt = authctxt; /*XXX*/
119
aa8003d6 120 /* challenge-response is implemented via keyboard interactive */
5ba55ada 121 if (options.challenge_response_authentication)
d464095c 122 options.kbd_interactive_authentication = 1;
10f72868 123 if (options.pam_authentication_via_kbd_int)
124 options.kbd_interactive_authentication = 1;
d464095c 125
a306f2dd 126 dispatch_init(&protocol_error);
127 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
94ec8c6b 128 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
bb5639fe 129 do_authenticated(authctxt);
a306f2dd 130}
131
396c147e 132static void
24ca6821 133protocol_error(int type, int plen, u_int32_t seq, void *ctxt)
a306f2dd 134{
135 log("auth: protocol error: type %d plen %d", type, plen);
136 packet_start(SSH2_MSG_UNIMPLEMENTED);
24ca6821 137 packet_put_int(seq);
a306f2dd 138 packet_send();
139 packet_write_wait();
140}
141
396c147e 142static void
24ca6821 143input_service_request(int type, int plen, u_int32_t seq, void *ctxt)
a306f2dd 144{
94ec8c6b 145 Authctxt *authctxt = ctxt;
1e3b8b07 146 u_int len;
a306f2dd 147 int accept = 0;
148 char *service = packet_get_string(&len);
149 packet_done();
150
94ec8c6b 151 if (authctxt == NULL)
152 fatal("input_service_request: no authctxt");
153
a306f2dd 154 if (strcmp(service, "ssh-userauth") == 0) {
94ec8c6b 155 if (!authctxt->success) {
a306f2dd 156 accept = 1;
157 /* now we can handle user-auth requests */
158 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
159 }
160 }
161 /* XXX all other service requests are denied */
162
163 if (accept) {
164 packet_start(SSH2_MSG_SERVICE_ACCEPT);
165 packet_put_cstring(service);
166 packet_send();
167 packet_write_wait();
168 } else {
169 debug("bad service request %s", service);
170 packet_disconnect("bad service request %s", service);
171 }
172 xfree(service);
173}
174
396c147e 175static void
24ca6821 176input_userauth_request(int type, int plen, u_int32_t seq, void *ctxt)
a306f2dd 177{
94ec8c6b 178 Authctxt *authctxt = ctxt;
179 Authmethod *m = NULL;
59c97189 180 char *user, *service, *method, *style = NULL;
a306f2dd 181 int authenticated = 0;
a306f2dd 182
94ec8c6b 183 if (authctxt == NULL)
184 fatal("input_userauth_request: no authctxt");
a306f2dd 185
94ec8c6b 186 user = packet_get_string(NULL);
187 service = packet_get_string(NULL);
188 method = packet_get_string(NULL);
189 debug("userauth-request for user %s service %s method %s", user, service, method);
8abcdba4 190 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
94ec8c6b 191
59c97189 192 if ((style = strchr(user, ':')) != NULL)
193 *style++ = 0;
194
2b87da3b 195 if (authctxt->attempt++ == 0) {
94ec8c6b 196 /* setup auth context */
197 struct passwd *pw = NULL;
94ec8c6b 198 pw = getpwnam(user);
199 if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
200 authctxt->pw = pwcopy(pw);
201 authctxt->valid = 1;
202 debug2("input_userauth_request: setting up authctxt for %s", user);
203#ifdef USE_PAM
04fc7a67 204 start_pam(pw->pw_name);
94ec8c6b 205#endif
206 } else {
207 log("input_userauth_request: illegal user %s", user);
04fc7a67 208#ifdef USE_PAM
209 start_pam("NOUSER");
210#endif
94ec8c6b 211 }
6172e290 212 setproctitle("%s", pw ? user : "unknown");
94ec8c6b 213 authctxt->user = xstrdup(user);
214 authctxt->service = xstrdup(service);
2a6a054e 215 authctxt->style = style ? xstrdup(style) : NULL;
216 } else if (strcmp(user, authctxt->user) != 0 ||
217 strcmp(service, authctxt->service) != 0) {
218 packet_disconnect("Change of username or service not allowed: "
219 "(%s,%s) -> (%s,%s)",
220 authctxt->user, authctxt->service, user, service);
a306f2dd 221 }
59c97189 222 /* reset state */
2f293d43 223 auth2_challenge_stop(authctxt);
59c97189 224 authctxt->postponed = 0;
9cd45ea4 225
59c97189 226 /* try to authenticate user */
94ec8c6b 227 m = authmethod_lookup(method);
228 if (m != NULL) {
229 debug2("input_userauth_request: try method %s", method);
230 authenticated = m->userauth(authctxt);
9cd45ea4 231 }
d9cd3575 232 userauth_finish(authctxt, authenticated, method);
233
234 xfree(service);
235 xfree(user);
236 xfree(method);
237}
238
239void
240userauth_finish(Authctxt *authctxt, int authenticated, char *method)
241{
4e81159c 242 char *methods;
243
59c97189 244 if (!authctxt->valid && authenticated)
245 fatal("INTERNAL ERROR: authenticated invalid user %s",
246 authctxt->user);
9cd45ea4 247
94ec8c6b 248 /* Special handling for root */
15853e93 249 if (authenticated && authctxt->pw->pw_uid == 0 &&
250 !auth_root_allowed(method))
a306f2dd 251 authenticated = 0;
a306f2dd 252
253#ifdef USE_PAM
edef62bf 254 if (authenticated && authctxt->user && !do_pam_account(authctxt->user,
255 NULL))
9cd45ea4 256 authenticated = 0;
a306f2dd 257#endif /* USE_PAM */
258
94ec8c6b 259 /* Log before sending the reply */
59c97189 260 auth_log(authctxt, authenticated, method, " ssh2");
261
4e81159c 262 if (authctxt->postponed)
263 return;
264
265 /* XXX todo: check if multiple auth methods are needed */
266 if (authenticated == 1) {
267 /* turn off userauth */
268 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
269 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
270 packet_send();
271 packet_write_wait();
272 /* now we can break out */
273 authctxt->success = 1;
274 } else {
19e810f6 275 if (authctxt->failures++ > AUTH_FAIL_MAX) {
276#ifdef WITH_AIXAUTHENTICATE
277 loginfailed(authctxt->user,
278 get_canonical_hostname(options.reverse_mapping_check),
279 "ssh");
280#endif /* WITH_AIXAUTHENTICATE */
4e81159c 281 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
19e810f6 282 }
4e81159c 283 methods = authmethods_get();
284 packet_start(SSH2_MSG_USERAUTH_FAILURE);
285 packet_put_cstring(methods);
286 packet_put_char(0); /* XXX partial success, unused */
287 packet_send();
288 packet_write_wait();
289 xfree(methods);
290 }
94ec8c6b 291}
292
396c147e 293static void
eea39c02 294userauth_banner(void)
295{
296 struct stat st;
297 char *banner = NULL;
298 off_t len, n;
299 int fd;
300
301 if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
302 return;
0715ec6c 303 if ((fd = open(options.banner, O_RDONLY)) < 0)
eea39c02 304 return;
eea39c02 305 if (fstat(fd, &st) < 0)
306 goto done;
307 len = st.st_size;
308 banner = xmalloc(len + 1);
309 if ((n = read(fd, banner, len)) < 0)
310 goto done;
311 banner[n] = '\0';
312 packet_start(SSH2_MSG_USERAUTH_BANNER);
313 packet_put_cstring(banner);
314 packet_put_cstring(""); /* language, unused */
315 packet_send();
316 debug("userauth_banner: sent");
317done:
318 if (banner)
319 xfree(banner);
320 close(fd);
321 return;
322}
94ec8c6b 323
396c147e 324static int
94ec8c6b 325userauth_none(Authctxt *authctxt)
a306f2dd 326{
94ec8c6b 327 /* disable method "none", only allowed one time */
328 Authmethod *m = authmethod_lookup("none");
329 if (m != NULL)
330 m->enabled = NULL;
a306f2dd 331 packet_done();
2b87da3b 332 userauth_banner();
4d33e531 333
94ec8c6b 334 if (authctxt->valid == 0)
335 return(0);
2b87da3b 336
94ec8c6b 337#ifdef HAVE_CYGWIN
e9571a2c 338 if (check_nt_auth(1, authctxt->pw) == 0)
94ec8c6b 339 return(0);
340#endif
a306f2dd 341#ifdef USE_PAM
94ec8c6b 342 return auth_pam_password(authctxt->pw, "");
4d33e531 343#elif defined(HAVE_OSF_SIA)
b7ccb051 344 return 0;
4d33e531 345#else /* !HAVE_OSF_SIA && !USE_PAM */
af774732 346 return auth_password(authctxt, "");
a306f2dd 347#endif /* USE_PAM */
348}
94ec8c6b 349
396c147e 350static int
94ec8c6b 351userauth_passwd(Authctxt *authctxt)
a306f2dd 352{
353 char *password;
354 int authenticated = 0;
355 int change;
1e3b8b07 356 u_int len;
a306f2dd 357 change = packet_get_char();
358 if (change)
359 log("password change not supported");
360 password = packet_get_string(&len);
361 packet_done();
94ec8c6b 362 if (authctxt->valid &&
363#ifdef HAVE_CYGWIN
e9571a2c 364 check_nt_auth(1, authctxt->pw) &&
94ec8c6b 365#endif
a306f2dd 366#ifdef USE_PAM
94ec8c6b 367 auth_pam_password(authctxt->pw, password) == 1)
4d33e531 368#elif defined(HAVE_OSF_SIA)
b7ccb051 369 auth_sia_password(authctxt->user, password) == 1)
4d33e531 370#else /* !USE_PAM && !HAVE_OSF_SIA */
af774732 371 auth_password(authctxt, password) == 1)
a306f2dd 372#endif /* USE_PAM */
373 authenticated = 1;
374 memset(password, 0, len);
375 xfree(password);
376 return authenticated;
377}
94ec8c6b 378
396c147e 379static int
94ec8c6b 380userauth_kbdint(Authctxt *authctxt)
381{
382 int authenticated = 0;
5ba55ada 383 char *lang, *devs;
94ec8c6b 384
385 lang = packet_get_string(NULL);
386 devs = packet_get_string(NULL);
387 packet_done();
388
5ba55ada 389 debug("keyboard-interactive devs %s", devs);
59c97189 390
5ba55ada 391 if (options.challenge_response_authentication)
d464095c 392 authenticated = auth2_challenge(authctxt, devs);
59c97189 393
8c9fe09e 394#ifdef USE_PAM
10f72868 395 if (authenticated == 0 && options.pam_authentication_via_kbd_int)
8c9fe09e 396 authenticated = auth2_pam(authctxt);
94ec8c6b 397#endif
94ec8c6b 398 xfree(devs);
5ba55ada 399 xfree(lang);
94ec8c6b 400#ifdef HAVE_CYGWIN
e9571a2c 401 if (check_nt_auth(0, authctxt->pw) == 0)
94ec8c6b 402 return(0);
403#endif
404 return authenticated;
405}
406
396c147e 407static int
94ec8c6b 408userauth_pubkey(Authctxt *authctxt)
a306f2dd 409{
410 Buffer b;
411 Key *key;
412 char *pkalg, *pkblob, *sig;
1e3b8b07 413 u_int alen, blen, slen;
fa08c86b 414 int have_sig, pktype;
a306f2dd 415 int authenticated = 0;
416
94ec8c6b 417 if (!authctxt->valid) {
418 debug2("userauth_pubkey: disabled because of invalid user");
a306f2dd 419 return 0;
420 }
421 have_sig = packet_get_char();
cbc5abf9 422 if (datafellows & SSH_BUG_PKAUTH) {
423 debug2("userauth_pubkey: SSH_BUG_PKAUTH");
424 /* no explicit pkalg given */
425 pkblob = packet_get_string(&blen);
426 buffer_init(&b);
427 buffer_append(&b, pkblob, blen);
428 /* so we have to extract the pkalg from the pkblob */
429 pkalg = buffer_get_string(&b, &alen);
430 buffer_free(&b);
431 } else {
432 pkalg = packet_get_string(&alen);
433 pkblob = packet_get_string(&blen);
434 }
fa08c86b 435 pktype = key_type_from_name(pkalg);
436 if (pktype == KEY_UNSPEC) {
cbc5abf9 437 /* this is perfectly legal */
438 log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
94ec8c6b 439 xfree(pkalg);
cbc5abf9 440 xfree(pkblob);
a306f2dd 441 return 0;
442 }
fa08c86b 443 key = key_from_blob(pkblob, blen);
a306f2dd 444 if (key != NULL) {
445 if (have_sig) {
446 sig = packet_get_string(&slen);
447 packet_done();
448 buffer_init(&b);
33de75a3 449 if (datafellows & SSH_OLD_SESSIONID) {
74fc9186 450 buffer_append(&b, session_id2, session_id2_len);
33de75a3 451 } else {
452 buffer_put_string(&b, session_id2, session_id2_len);
74fc9186 453 }
38c295d6 454 /* reconstruct packet */
a306f2dd 455 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
94ec8c6b 456 buffer_put_cstring(&b, authctxt->user);
38c295d6 457 buffer_put_cstring(&b,
cbc5abf9 458 datafellows & SSH_BUG_PKSERVICE ?
38c295d6 459 "ssh-userauth" :
94ec8c6b 460 authctxt->service);
cbc5abf9 461 if (datafellows & SSH_BUG_PKAUTH) {
462 buffer_put_char(&b, have_sig);
463 } else {
464 buffer_put_cstring(&b, "publickey");
465 buffer_put_char(&b, have_sig);
5cf13595 466 buffer_put_cstring(&b, pkalg);
cbc5abf9 467 }
38c295d6 468 buffer_put_string(&b, pkblob, blen);
fa08c86b 469#ifdef DEBUG_PK
a306f2dd 470 buffer_dump(&b);
471#endif
472 /* test for correct signature */
fa08c86b 473 if (user_key_allowed(authctxt->pw, key) &&
474 key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
a306f2dd 475 authenticated = 1;
476 buffer_clear(&b);
477 xfree(sig);
478 } else {
94ec8c6b 479 debug("test whether pkalg/pkblob are acceptable");
a306f2dd 480 packet_done();
94ec8c6b 481
a306f2dd 482 /* XXX fake reply and always send PK_OK ? */
1d1ffb87 483 /*
484 * XXX this allows testing whether a user is allowed
485 * to login: if you happen to have a valid pubkey this
486 * message is sent. the message is NEVER sent at all
487 * if a user is not allowed to login. is this an
488 * issue? -markus
489 */
fa08c86b 490 if (user_key_allowed(authctxt->pw, key)) {
a306f2dd 491 packet_start(SSH2_MSG_USERAUTH_PK_OK);
492 packet_put_string(pkalg, alen);
493 packet_put_string(pkblob, blen);
494 packet_send();
495 packet_write_wait();
25f4c264 496 authctxt->postponed = 1;
a306f2dd 497 }
498 }
94ec8c6b 499 if (authenticated != 1)
500 auth_clear_options();
a306f2dd 501 key_free(key);
502 }
fa08c86b 503 debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
a306f2dd 504 xfree(pkalg);
505 xfree(pkblob);
94ec8c6b 506#ifdef HAVE_CYGWIN
e9571a2c 507 if (check_nt_auth(0, authctxt->pw) == 0)
94ec8c6b 508 return(0);
509#endif
a306f2dd 510 return authenticated;
511}
512
396c147e 513static int
8002af61 514userauth_hostbased(Authctxt *authctxt)
515{
516 Buffer b;
517 Key *key;
8dddf799 518 char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
8002af61 519 u_int alen, blen, slen;
520 int pktype;
521 int authenticated = 0;
522
523 if (!authctxt->valid) {
524 debug2("userauth_hostbased: disabled because of invalid user");
525 return 0;
526 }
527 pkalg = packet_get_string(&alen);
528 pkblob = packet_get_string(&blen);
529 chost = packet_get_string(NULL);
530 cuser = packet_get_string(NULL);
531 sig = packet_get_string(&slen);
532
533 debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
534 cuser, chost, pkalg, slen);
535#ifdef DEBUG_PK
536 debug("signature:");
537 buffer_init(&b);
538 buffer_append(&b, sig, slen);
539 buffer_dump(&b);
540 buffer_free(&b);
541#endif
542 pktype = key_type_from_name(pkalg);
543 if (pktype == KEY_UNSPEC) {
544 /* this is perfectly legal */
545 log("userauth_hostbased: unsupported "
546 "public key algorithm: %s", pkalg);
547 goto done;
548 }
549 key = key_from_blob(pkblob, blen);
550 if (key == NULL) {
551 debug("userauth_hostbased: cannot decode key: %s", pkalg);
552 goto done;
553 }
8dddf799 554 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
555 authctxt->service;
8002af61 556 buffer_init(&b);
8dddf799 557 buffer_put_string(&b, session_id2, session_id2_len);
8002af61 558 /* reconstruct packet */
559 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
560 buffer_put_cstring(&b, authctxt->user);
8dddf799 561 buffer_put_cstring(&b, service);
8002af61 562 buffer_put_cstring(&b, "hostbased");
563 buffer_put_string(&b, pkalg, alen);
564 buffer_put_string(&b, pkblob, blen);
565 buffer_put_cstring(&b, chost);
566 buffer_put_cstring(&b, cuser);
567#ifdef DEBUG_PK
568 buffer_dump(&b);
569#endif
570 /* test for allowed key and correct signature */
571 if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
572 key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
573 authenticated = 1;
574
575 buffer_clear(&b);
576 key_free(key);
577
578done:
579 debug2("userauth_hostbased: authenticated %d", authenticated);
580 xfree(pkalg);
581 xfree(pkblob);
582 xfree(cuser);
583 xfree(chost);
584 xfree(sig);
585 return authenticated;
586}
587
94ec8c6b 588/* get current user */
a306f2dd 589
590struct passwd*
591auth_get_user(void)
592{
94ec8c6b 593 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
a306f2dd 594}
595
94ec8c6b 596#define DELIM ","
597
ffb215be 598static char *
94ec8c6b 599authmethods_get(void)
a306f2dd 600{
94ec8c6b 601 Authmethod *method = NULL;
1e3b8b07 602 u_int size = 0;
94ec8c6b 603 char *list;
604
605 for (method = authmethods; method->name != NULL; method++) {
606 if (strcmp(method->name, "none") == 0)
607 continue;
608 if (method->enabled != NULL && *(method->enabled) != 0) {
609 if (size != 0)
610 size += strlen(DELIM);
611 size += strlen(method->name);
a306f2dd 612 }
94ec8c6b 613 }
614 size++; /* trailing '\0' */
615 list = xmalloc(size);
616 list[0] = '\0';
617
618 for (method = authmethods; method->name != NULL; method++) {
619 if (strcmp(method->name, "none") == 0)
620 continue;
621 if (method->enabled != NULL && *(method->enabled) != 0) {
622 if (list[0] != '\0')
623 strlcat(list, DELIM, size);
624 strlcat(list, method->name, size);
a306f2dd 625 }
626 }
94ec8c6b 627 return list;
628}
629
396c147e 630static Authmethod *
94ec8c6b 631authmethod_lookup(const char *name)
632{
633 Authmethod *method = NULL;
634 if (name != NULL)
635 for (method = authmethods; method->name != NULL; method++)
636 if (method->enabled != NULL &&
637 *(method->enabled) != 0 &&
638 strcmp(name, method->name) == 0)
639 return method;
640 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
641 return NULL;
a306f2dd 642}
643
644/* return 1 if user allows given key */
396c147e 645static int
96a7b0cc 646user_key_allowed2(struct passwd *pw, Key *key, char *file)
a306f2dd 647{
96a7b0cc 648 char line[8192];
a306f2dd 649 int found_key = 0;
a306f2dd 650 FILE *f;
1e3b8b07 651 u_long linenum = 0;
a306f2dd 652 struct stat st;
653 Key *found;
306feb91 654 char *fp;
a306f2dd 655
94ec8c6b 656 if (pw == NULL)
657 return 0;
658
a306f2dd 659 /* Temporarily use the user's uid. */
63bd8c36 660 temporarily_use_uid(pw);
a306f2dd 661
c8445989 662 debug("trying public key file %s", file);
a306f2dd 663
664 /* Fail quietly if file does not exist */
665 if (stat(file, &st) < 0) {
666 /* Restore the privileged uid. */
667 restore_uid();
668 return 0;
669 }
670 /* Open the file containing the authorized keys. */
671 f = fopen(file, "r");
672 if (!f) {
673 /* Restore the privileged uid. */
674 restore_uid();
675 return 0;
676 }
c8445989 677 if (options.strict_modes &&
0c9664c2 678 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
c8445989 679 fclose(f);
680 log("Authentication refused: %s", line);
681 restore_uid();
682 return 0;
a306f2dd 683 }
c8445989 684
a306f2dd 685 found_key = 0;
de273eef 686 found = key_new(key->type);
a306f2dd 687
688 while (fgets(line, sizeof(line), f)) {
38c295d6 689 char *cp, *options = NULL;
a306f2dd 690 linenum++;
691 /* Skip leading whitespace, empty and comment lines. */
692 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
693 ;
694 if (!*cp || *cp == '\n' || *cp == '#')
695 continue;
38c295d6 696
ddcfed57 697 if (key_read(found, &cp) != 1) {
38c295d6 698 /* no key? check if there are options for this key */
699 int quoted = 0;
fa08c86b 700 debug2("user_key_allowed: check options: '%s'", cp);
38c295d6 701 options = cp;
702 for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
703 if (*cp == '\\' && cp[1] == '"')
704 cp++; /* Skip both */
705 else if (*cp == '"')
706 quoted = !quoted;
707 }
708 /* Skip remaining whitespace. */
709 for (; *cp == ' ' || *cp == '\t'; cp++)
710 ;
ddcfed57 711 if (key_read(found, &cp) != 1) {
fa08c86b 712 debug2("user_key_allowed: advance: '%s'", cp);
38c295d6 713 /* still no key? advance to next line*/
714 continue;
715 }
716 }
717 if (key_equal(found, key) &&
42f11eb2 718 auth_parse_options(pw, options, file, linenum) == 1) {
a306f2dd 719 found_key = 1;
1bdee08c 720 debug("matching key found: file %s, line %lu",
a306f2dd 721 file, linenum);
306feb91 722 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
723 verbose("Found matching %s key: %s",
184eed6a 724 key_type(found), fp);
306feb91 725 xfree(fp);
a306f2dd 726 break;
727 }
728 }
729 restore_uid();
730 fclose(f);
731 key_free(found);
539af7f5 732 if (!found_key)
733 debug2("key not found");
a306f2dd 734 return found_key;
735}
8002af61 736
96a7b0cc 737/* check whether given key is in .ssh/authorized_keys* */
396c147e 738static int
96a7b0cc 739user_key_allowed(struct passwd *pw, Key *key)
740{
741 int success;
742 char *file;
743
744 file = authorized_keys_file(pw);
745 success = user_key_allowed2(pw, key, file);
746 xfree(file);
747 if (success)
748 return success;
749
750 /* try suffix "2" for backward compat, too */
751 file = authorized_keys_file2(pw);
752 success = user_key_allowed2(pw, key, file);
753 xfree(file);
754 return success;
755}
756
8002af61 757/* return 1 if given hostkey is allowed */
396c147e 758static int
57a5edd8 759hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
8002af61 760 Key *key)
761{
8002af61 762 const char *resolvedname, *ipaddr, *lookup;
17a3011c 763 HostStatus host_status;
764 int len;
8002af61 765
766 resolvedname = get_canonical_hostname(options.reverse_mapping_check);
767 ipaddr = get_remote_ipaddr();
768
f98c3421 769 debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
770 chost, resolvedname, ipaddr);
8002af61 771
772 if (options.hostbased_uses_name_from_packet_only) {
773 if (auth_rhosts2(pw, cuser, chost, chost) == 0)
774 return 0;
775 lookup = chost;
776 } else {
f98c3421 777 if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
778 debug2("stripping trailing dot from chost %s", chost);
779 chost[len - 1] = '\0';
780 }
8002af61 781 if (strcasecmp(resolvedname, chost) != 0)
782 log("userauth_hostbased mismatch: "
783 "client sends %s, but we resolve %s to %s",
784 chost, ipaddr, resolvedname);
785 if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
786 return 0;
787 lookup = resolvedname;
788 }
789 debug2("userauth_hostbased: access allowed by auth_rhosts2");
790
d0c8ca5c 791 host_status = check_key_in_hostfiles(pw, key, lookup,
792 _PATH_SSH_SYSTEM_HOSTFILE,
73473230 793 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
d0c8ca5c 794
795 /* backward compat if no key has been found. */
796 if (host_status == HOST_NEW)
797 host_status = check_key_in_hostfiles(pw, key, lookup,
798 _PATH_SSH_SYSTEM_HOSTFILE2,
73473230 799 options.ignore_user_known_hosts ? NULL :
800 _PATH_SSH_USER_HOSTFILE2);
8002af61 801
8002af61 802 return (host_status == HOST_OK);
803}
d0c8ca5c 804
This page took 0.242936 seconds and 5 git commands to generate.