]> andersk Git - openssh.git/blame - auth2.c
- (djm) Make privsep work with PAM (still experimental)
[openssh.git] / auth2.c
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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"
5f1f36b5 26RCSID("$OpenBSD: auth2.c,v 1.89 2002/03/19 14:27:39 markus 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"
8002af61 50#include "hostfile.h"
51#include "canohost.h"
5ba55ada 52#include "match.h"
1853d1ef 53#include "monitor_wrap.h"
a306f2dd 54
55/* import */
56extern ServerOptions options;
1e3b8b07 57extern u_char *session_id2;
a306f2dd 58extern int session_id2_len;
59
1853d1ef 60Authctxt *x_authctxt = NULL;
94ec8c6b 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
7819b5c3 72static void input_service_request(int, u_int32_t, void *);
73static void input_userauth_request(int, u_int32_t, void *);
a306f2dd 74
a306f2dd 75/* helper */
396c147e 76static Authmethod *authmethod_lookup(const char *);
ffb215be 77static char *authmethods_get(void);
1853d1ef 78int user_key_allowed(struct passwd *, Key *);
79int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
a306f2dd 80
94ec8c6b 81/* auth */
396c147e 82static void userauth_banner(void);
83static int userauth_none(Authctxt *);
84static int userauth_passwd(Authctxt *);
85static int userauth_pubkey(Authctxt *);
86static int userauth_hostbased(Authctxt *);
87static int userauth_kbdint(Authctxt *);
94ec8c6b 88
89Authmethod authmethods[] = {
90 {"none",
91 userauth_none,
92 &one},
93 {"publickey",
94 userauth_pubkey,
fa08c86b 95 &options.pubkey_authentication},
94ec8c6b 96 {"password",
97 userauth_passwd,
98 &options.password_authentication},
c845316f 99 {"keyboard-interactive",
100 userauth_kbdint,
101 &options.kbd_interactive_authentication},
8002af61 102 {"hostbased",
103 userauth_hostbased,
104 &options.hostbased_authentication},
94ec8c6b 105 {NULL, NULL, NULL}
a306f2dd 106};
a306f2dd 107
108/*
94ec8c6b 109 * loop until authctxt->success == TRUE
a306f2dd 110 */
111
1b34c1b3 112Authctxt *
d5bb9418 113do_authentication2(void)
a306f2dd 114{
59c97189 115 Authctxt *authctxt = authctxt_new();
116
94ec8c6b 117 x_authctxt = authctxt; /*XXX*/
118
aa8003d6 119 /* challenge-response is implemented via keyboard interactive */
5ba55ada 120 if (options.challenge_response_authentication)
d464095c 121 options.kbd_interactive_authentication = 1;
10f72868 122 if (options.pam_authentication_via_kbd_int)
123 options.kbd_interactive_authentication = 1;
d464095c 124
6367063f 125 dispatch_init(&dispatch_protocol_error);
a306f2dd 126 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
94ec8c6b 127 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1b34c1b3 128
129 return (authctxt);
a306f2dd 130}
131
396c147e 132static void
7819b5c3 133input_service_request(int type, u_int32_t seq, void *ctxt)
a306f2dd 134{
94ec8c6b 135 Authctxt *authctxt = ctxt;
1e3b8b07 136 u_int len;
a306f2dd 137 int accept = 0;
138 char *service = packet_get_string(&len);
95500969 139 packet_check_eom();
a306f2dd 140
94ec8c6b 141 if (authctxt == NULL)
142 fatal("input_service_request: no authctxt");
143
a306f2dd 144 if (strcmp(service, "ssh-userauth") == 0) {
94ec8c6b 145 if (!authctxt->success) {
a306f2dd 146 accept = 1;
147 /* now we can handle user-auth requests */
148 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
149 }
150 }
151 /* XXX all other service requests are denied */
152
153 if (accept) {
154 packet_start(SSH2_MSG_SERVICE_ACCEPT);
155 packet_put_cstring(service);
156 packet_send();
157 packet_write_wait();
158 } else {
159 debug("bad service request %s", service);
160 packet_disconnect("bad service request %s", service);
161 }
162 xfree(service);
163}
164
396c147e 165static void
7819b5c3 166input_userauth_request(int type, u_int32_t seq, void *ctxt)
a306f2dd 167{
94ec8c6b 168 Authctxt *authctxt = ctxt;
169 Authmethod *m = NULL;
59c97189 170 char *user, *service, *method, *style = NULL;
a306f2dd 171 int authenticated = 0;
a306f2dd 172
94ec8c6b 173 if (authctxt == NULL)
174 fatal("input_userauth_request: no authctxt");
a306f2dd 175
94ec8c6b 176 user = packet_get_string(NULL);
177 service = packet_get_string(NULL);
178 method = packet_get_string(NULL);
179 debug("userauth-request for user %s service %s method %s", user, service, method);
8abcdba4 180 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
94ec8c6b 181
59c97189 182 if ((style = strchr(user, ':')) != NULL)
183 *style++ = 0;
184
2b87da3b 185 if (authctxt->attempt++ == 0) {
63284fbb 186 /* setup auth context */
f7ed12f1 187 authctxt->pw = PRIVSEP(getpwnamallow(user));
188 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
94ec8c6b 189 authctxt->valid = 1;
190 debug2("input_userauth_request: setting up authctxt for %s", user);
191#ifdef USE_PAM
ad200abb 192 PRIVSEP(start_pam(authctxt->pw->pw_name));
94ec8c6b 193#endif
194 } else {
195 log("input_userauth_request: illegal user %s", user);
04fc7a67 196#ifdef USE_PAM
ad200abb 197 PRIVSEP(start_pam("NOUSER"));
04fc7a67 198#endif
94ec8c6b 199 }
5f1f36b5 200 setproctitle("%s%s", authctxt->pw ? user : "unknown",
1853d1ef 201 use_privsep ? " [net]" : "");
94ec8c6b 202 authctxt->user = xstrdup(user);
203 authctxt->service = xstrdup(service);
2a6a054e 204 authctxt->style = style ? xstrdup(style) : NULL;
1853d1ef 205 if (use_privsep)
206 mm_inform_authserv(service, style);
2a6a054e 207 } else if (strcmp(user, authctxt->user) != 0 ||
208 strcmp(service, authctxt->service) != 0) {
209 packet_disconnect("Change of username or service not allowed: "
210 "(%s,%s) -> (%s,%s)",
211 authctxt->user, authctxt->service, user, service);
a306f2dd 212 }
59c97189 213 /* reset state */
2f293d43 214 auth2_challenge_stop(authctxt);
59c97189 215 authctxt->postponed = 0;
9cd45ea4 216
59c97189 217 /* try to authenticate user */
94ec8c6b 218 m = authmethod_lookup(method);
219 if (m != NULL) {
220 debug2("input_userauth_request: try method %s", method);
221 authenticated = m->userauth(authctxt);
9cd45ea4 222 }
d9cd3575 223 userauth_finish(authctxt, authenticated, method);
224
225 xfree(service);
226 xfree(user);
227 xfree(method);
228}
229
230void
231userauth_finish(Authctxt *authctxt, int authenticated, char *method)
232{
4e81159c 233 char *methods;
234
59c97189 235 if (!authctxt->valid && authenticated)
236 fatal("INTERNAL ERROR: authenticated invalid user %s",
237 authctxt->user);
9cd45ea4 238
94ec8c6b 239 /* Special handling for root */
15853e93 240 if (authenticated && authctxt->pw->pw_uid == 0 &&
241 !auth_root_allowed(method))
a306f2dd 242 authenticated = 0;
a306f2dd 243
244#ifdef USE_PAM
ad200abb 245 if (!use_privsep && authenticated && authctxt->user &&
246 !do_pam_account(authctxt->user, NULL))
9cd45ea4 247 authenticated = 0;
a306f2dd 248#endif /* USE_PAM */
249
94ec8c6b 250 /* Log before sending the reply */
59c97189 251 auth_log(authctxt, authenticated, method, " ssh2");
252
4e81159c 253 if (authctxt->postponed)
254 return;
255
256 /* XXX todo: check if multiple auth methods are needed */
257 if (authenticated == 1) {
258 /* turn off userauth */
6367063f 259 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
4e81159c 260 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
261 packet_send();
262 packet_write_wait();
263 /* now we can break out */
264 authctxt->success = 1;
265 } else {
19e810f6 266 if (authctxt->failures++ > AUTH_FAIL_MAX) {
267#ifdef WITH_AIXAUTHENTICATE
268 loginfailed(authctxt->user,
983784a1 269 get_canonical_hostname(options.verify_reverse_mapping),
19e810f6 270 "ssh");
271#endif /* WITH_AIXAUTHENTICATE */
4e81159c 272 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
19e810f6 273 }
4e81159c 274 methods = authmethods_get();
275 packet_start(SSH2_MSG_USERAUTH_FAILURE);
276 packet_put_cstring(methods);
277 packet_put_char(0); /* XXX partial success, unused */
278 packet_send();
279 packet_write_wait();
280 xfree(methods);
281 }
94ec8c6b 282}
283
396c147e 284static void
eea39c02 285userauth_banner(void)
286{
287 struct stat st;
288 char *banner = NULL;
289 off_t len, n;
290 int fd;
291
292 if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
293 return;
0715ec6c 294 if ((fd = open(options.banner, O_RDONLY)) < 0)
eea39c02 295 return;
eea39c02 296 if (fstat(fd, &st) < 0)
297 goto done;
298 len = st.st_size;
299 banner = xmalloc(len + 1);
300 if ((n = read(fd, banner, len)) < 0)
301 goto done;
302 banner[n] = '\0';
303 packet_start(SSH2_MSG_USERAUTH_BANNER);
304 packet_put_cstring(banner);
305 packet_put_cstring(""); /* language, unused */
306 packet_send();
307 debug("userauth_banner: sent");
308done:
309 if (banner)
310 xfree(banner);
311 close(fd);
312 return;
313}
94ec8c6b 314
396c147e 315static int
94ec8c6b 316userauth_none(Authctxt *authctxt)
a306f2dd 317{
94ec8c6b 318 /* disable method "none", only allowed one time */
319 Authmethod *m = authmethod_lookup("none");
320 if (m != NULL)
321 m->enabled = NULL;
95500969 322 packet_check_eom();
2b87da3b 323 userauth_banner();
4d33e531 324
94ec8c6b 325 if (authctxt->valid == 0)
326 return(0);
63284fbb 327
328#ifdef HAVE_CYGWIN
329 if (check_nt_auth(1, authctxt->pw) == 0)
330 return(0);
94ec8c6b 331#endif
1853d1ef 332 return PRIVSEP(auth_password(authctxt, ""));
a306f2dd 333}
94ec8c6b 334
396c147e 335static int
94ec8c6b 336userauth_passwd(Authctxt *authctxt)
a306f2dd 337{
338 char *password;
339 int authenticated = 0;
340 int change;
1e3b8b07 341 u_int len;
a306f2dd 342 change = packet_get_char();
343 if (change)
344 log("password change not supported");
345 password = packet_get_string(&len);
95500969 346 packet_check_eom();
63284fbb 347 if (authctxt->valid &&
348#ifdef HAVE_CYGWIN
349 check_nt_auth(1, authctxt->pw) &&
94ec8c6b 350#endif
1853d1ef 351 PRIVSEP(auth_password(authctxt, password)) == 1)
63284fbb 352 authenticated = 1;
a306f2dd 353 memset(password, 0, len);
354 xfree(password);
355 return authenticated;
356}
94ec8c6b 357
396c147e 358static int
94ec8c6b 359userauth_kbdint(Authctxt *authctxt)
360{
361 int authenticated = 0;
5ba55ada 362 char *lang, *devs;
94ec8c6b 363
364 lang = packet_get_string(NULL);
365 devs = packet_get_string(NULL);
95500969 366 packet_check_eom();
94ec8c6b 367
5ba55ada 368 debug("keyboard-interactive devs %s", devs);
59c97189 369
5ba55ada 370 if (options.challenge_response_authentication)
d464095c 371 authenticated = auth2_challenge(authctxt, devs);
59c97189 372
8c9fe09e 373#ifdef USE_PAM
10f72868 374 if (authenticated == 0 && options.pam_authentication_via_kbd_int)
8c9fe09e 375 authenticated = auth2_pam(authctxt);
94ec8c6b 376#endif
94ec8c6b 377 xfree(devs);
5ba55ada 378 xfree(lang);
94ec8c6b 379#ifdef HAVE_CYGWIN
e9571a2c 380 if (check_nt_auth(0, authctxt->pw) == 0)
94ec8c6b 381 return(0);
382#endif
383 return authenticated;
384}
385
396c147e 386static int
94ec8c6b 387userauth_pubkey(Authctxt *authctxt)
a306f2dd 388{
389 Buffer b;
67fa09f5 390 Key *key = NULL;
c66f9d0e 391 char *pkalg;
392 u_char *pkblob, *sig;
1e3b8b07 393 u_int alen, blen, slen;
fa08c86b 394 int have_sig, pktype;
a306f2dd 395 int authenticated = 0;
396
94ec8c6b 397 if (!authctxt->valid) {
398 debug2("userauth_pubkey: disabled because of invalid user");
a306f2dd 399 return 0;
400 }
401 have_sig = packet_get_char();
cbc5abf9 402 if (datafellows & SSH_BUG_PKAUTH) {
403 debug2("userauth_pubkey: SSH_BUG_PKAUTH");
404 /* no explicit pkalg given */
405 pkblob = packet_get_string(&blen);
406 buffer_init(&b);
407 buffer_append(&b, pkblob, blen);
408 /* so we have to extract the pkalg from the pkblob */
409 pkalg = buffer_get_string(&b, &alen);
410 buffer_free(&b);
411 } else {
412 pkalg = packet_get_string(&alen);
413 pkblob = packet_get_string(&blen);
414 }
fa08c86b 415 pktype = key_type_from_name(pkalg);
416 if (pktype == KEY_UNSPEC) {
cbc5abf9 417 /* this is perfectly legal */
67fa09f5 418 log("userauth_pubkey: unsupported public key algorithm: %s",
419 pkalg);
420 goto done;
a306f2dd 421 }
fa08c86b 422 key = key_from_blob(pkblob, blen);
67fa09f5 423 if (key == NULL) {
424 error("userauth_pubkey: cannot decode key: %s", pkalg);
425 goto done;
426 }
427 if (key->type != pktype) {
428 error("userauth_pubkey: type mismatch for decoded key "
429 "(received %d, expected %d)", key->type, pktype);
430 goto done;
431 }
432 if (have_sig) {
433 sig = packet_get_string(&slen);
434 packet_check_eom();
435 buffer_init(&b);
436 if (datafellows & SSH_OLD_SESSIONID) {
437 buffer_append(&b, session_id2, session_id2_len);
438 } else {
439 buffer_put_string(&b, session_id2, session_id2_len);
440 }
441 /* reconstruct packet */
442 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
443 buffer_put_cstring(&b, authctxt->user);
444 buffer_put_cstring(&b,
445 datafellows & SSH_BUG_PKSERVICE ?
446 "ssh-userauth" :
447 authctxt->service);
448 if (datafellows & SSH_BUG_PKAUTH) {
449 buffer_put_char(&b, have_sig);
450 } else {
451 buffer_put_cstring(&b, "publickey");
452 buffer_put_char(&b, have_sig);
453 buffer_put_cstring(&b, pkalg);
454 }
455 buffer_put_string(&b, pkblob, blen);
fa08c86b 456#ifdef DEBUG_PK
67fa09f5 457 buffer_dump(&b);
a306f2dd 458#endif
67fa09f5 459 /* test for correct signature */
1853d1ef 460 authenticated = 0;
461 if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
462 PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
463 buffer_len(&b))) == 1)
63284fbb 464 authenticated = 1;
67fa09f5 465 buffer_clear(&b);
466 xfree(sig);
467 } else {
468 debug("test whether pkalg/pkblob are acceptable");
469 packet_check_eom();
470
471 /* XXX fake reply and always send PK_OK ? */
472 /*
473 * XXX this allows testing whether a user is allowed
474 * to login: if you happen to have a valid pubkey this
475 * message is sent. the message is NEVER sent at all
476 * if a user is not allowed to login. is this an
477 * issue? -markus
478 */
1853d1ef 479 if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
67fa09f5 480 packet_start(SSH2_MSG_USERAUTH_PK_OK);
481 packet_put_string(pkalg, alen);
482 packet_put_string(pkblob, blen);
483 packet_send();
484 packet_write_wait();
485 authctxt->postponed = 1;
a306f2dd 486 }
a306f2dd 487 }
67fa09f5 488 if (authenticated != 1)
489 auth_clear_options();
490done:
fa08c86b 491 debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
67fa09f5 492 if (key != NULL)
493 key_free(key);
a306f2dd 494 xfree(pkalg);
495 xfree(pkblob);
94ec8c6b 496#ifdef HAVE_CYGWIN
e9571a2c 497 if (check_nt_auth(0, authctxt->pw) == 0)
94ec8c6b 498 return(0);
499#endif
a306f2dd 500 return authenticated;
501}
502
396c147e 503static int
8002af61 504userauth_hostbased(Authctxt *authctxt)
505{
506 Buffer b;
67fa09f5 507 Key *key = NULL;
c66f9d0e 508 char *pkalg, *cuser, *chost, *service;
509 u_char *pkblob, *sig;
8002af61 510 u_int alen, blen, slen;
511 int pktype;
512 int authenticated = 0;
513
514 if (!authctxt->valid) {
515 debug2("userauth_hostbased: disabled because of invalid user");
516 return 0;
517 }
518 pkalg = packet_get_string(&alen);
519 pkblob = packet_get_string(&blen);
520 chost = packet_get_string(NULL);
521 cuser = packet_get_string(NULL);
522 sig = packet_get_string(&slen);
523
524 debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
525 cuser, chost, pkalg, slen);
526#ifdef DEBUG_PK
527 debug("signature:");
528 buffer_init(&b);
529 buffer_append(&b, sig, slen);
530 buffer_dump(&b);
531 buffer_free(&b);
532#endif
533 pktype = key_type_from_name(pkalg);
534 if (pktype == KEY_UNSPEC) {
535 /* this is perfectly legal */
536 log("userauth_hostbased: unsupported "
537 "public key algorithm: %s", pkalg);
538 goto done;
539 }
540 key = key_from_blob(pkblob, blen);
541 if (key == NULL) {
67fa09f5 542 error("userauth_hostbased: cannot decode key: %s", pkalg);
543 goto done;
544 }
545 if (key->type != pktype) {
546 error("userauth_hostbased: type mismatch for decoded key "
547 "(received %d, expected %d)", key->type, pktype);
8002af61 548 goto done;
549 }
8dddf799 550 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
551 authctxt->service;
8002af61 552 buffer_init(&b);
8dddf799 553 buffer_put_string(&b, session_id2, session_id2_len);
8002af61 554 /* reconstruct packet */
555 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
556 buffer_put_cstring(&b, authctxt->user);
8dddf799 557 buffer_put_cstring(&b, service);
8002af61 558 buffer_put_cstring(&b, "hostbased");
559 buffer_put_string(&b, pkalg, alen);
560 buffer_put_string(&b, pkblob, blen);
561 buffer_put_cstring(&b, chost);
562 buffer_put_cstring(&b, cuser);
563#ifdef DEBUG_PK
564 buffer_dump(&b);
565#endif
566 /* test for allowed key and correct signature */
1853d1ef 567 authenticated = 0;
568 if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
569 PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
570 buffer_len(&b))) == 1)
63284fbb 571 authenticated = 1;
8002af61 572
573 buffer_clear(&b);
8002af61 574done:
575 debug2("userauth_hostbased: authenticated %d", authenticated);
67fa09f5 576 if (key != NULL)
577 key_free(key);
8002af61 578 xfree(pkalg);
579 xfree(pkblob);
580 xfree(cuser);
581 xfree(chost);
582 xfree(sig);
583 return authenticated;
584}
585
94ec8c6b 586/* get current user */
a306f2dd 587
588struct passwd*
589auth_get_user(void)
590{
94ec8c6b 591 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
a306f2dd 592}
593
94ec8c6b 594#define DELIM ","
595
ffb215be 596static char *
94ec8c6b 597authmethods_get(void)
a306f2dd 598{
94ec8c6b 599 Authmethod *method = NULL;
3469eac4 600 Buffer b;
94ec8c6b 601 char *list;
602
3469eac4 603 buffer_init(&b);
94ec8c6b 604 for (method = authmethods; method->name != NULL; method++) {
605 if (strcmp(method->name, "none") == 0)
606 continue;
607 if (method->enabled != NULL && *(method->enabled) != 0) {
3469eac4 608 if (buffer_len(&b) > 0)
609 buffer_append(&b, ",", 1);
610 buffer_append(&b, method->name, strlen(method->name));
a306f2dd 611 }
612 }
3469eac4 613 buffer_append(&b, "\0", 1);
614 list = xstrdup(buffer_ptr(&b));
615 buffer_free(&b);
94ec8c6b 616 return list;
617}
618
396c147e 619static Authmethod *
94ec8c6b 620authmethod_lookup(const char *name)
621{
622 Authmethod *method = NULL;
623 if (name != NULL)
624 for (method = authmethods; method->name != NULL; method++)
625 if (method->enabled != NULL &&
626 *(method->enabled) != 0 &&
627 strcmp(name, method->name) == 0)
628 return method;
629 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
630 return NULL;
a306f2dd 631}
632
633/* return 1 if user allows given key */
396c147e 634static int
96a7b0cc 635user_key_allowed2(struct passwd *pw, Key *key, char *file)
a306f2dd 636{
96a7b0cc 637 char line[8192];
a306f2dd 638 int found_key = 0;
a306f2dd 639 FILE *f;
1e3b8b07 640 u_long linenum = 0;
a306f2dd 641 struct stat st;
642 Key *found;
306feb91 643 char *fp;
a306f2dd 644
94ec8c6b 645 if (pw == NULL)
646 return 0;
647
a306f2dd 648 /* Temporarily use the user's uid. */
63bd8c36 649 temporarily_use_uid(pw);
a306f2dd 650
c8445989 651 debug("trying public key file %s", file);
a306f2dd 652
653 /* Fail quietly if file does not exist */
654 if (stat(file, &st) < 0) {
655 /* Restore the privileged uid. */
656 restore_uid();
657 return 0;
658 }
659 /* Open the file containing the authorized keys. */
660 f = fopen(file, "r");
661 if (!f) {
662 /* Restore the privileged uid. */
663 restore_uid();
664 return 0;
665 }
c8445989 666 if (options.strict_modes &&
0c9664c2 667 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
c8445989 668 fclose(f);
669 log("Authentication refused: %s", line);
670 restore_uid();
671 return 0;
a306f2dd 672 }
c8445989 673
a306f2dd 674 found_key = 0;
de273eef 675 found = key_new(key->type);
a306f2dd 676
677 while (fgets(line, sizeof(line), f)) {
38c295d6 678 char *cp, *options = NULL;
a306f2dd 679 linenum++;
680 /* Skip leading whitespace, empty and comment lines. */
681 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
682 ;
683 if (!*cp || *cp == '\n' || *cp == '#')
684 continue;
38c295d6 685
ddcfed57 686 if (key_read(found, &cp) != 1) {
38c295d6 687 /* no key? check if there are options for this key */
688 int quoted = 0;
fa08c86b 689 debug2("user_key_allowed: check options: '%s'", cp);
38c295d6 690 options = cp;
691 for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
692 if (*cp == '\\' && cp[1] == '"')
693 cp++; /* Skip both */
694 else if (*cp == '"')
695 quoted = !quoted;
696 }
697 /* Skip remaining whitespace. */
698 for (; *cp == ' ' || *cp == '\t'; cp++)
699 ;
ddcfed57 700 if (key_read(found, &cp) != 1) {
fa08c86b 701 debug2("user_key_allowed: advance: '%s'", cp);
38c295d6 702 /* still no key? advance to next line*/
703 continue;
704 }
705 }
706 if (key_equal(found, key) &&
42f11eb2 707 auth_parse_options(pw, options, file, linenum) == 1) {
a306f2dd 708 found_key = 1;
1bdee08c 709 debug("matching key found: file %s, line %lu",
a306f2dd 710 file, linenum);
306feb91 711 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
712 verbose("Found matching %s key: %s",
184eed6a 713 key_type(found), fp);
306feb91 714 xfree(fp);
a306f2dd 715 break;
716 }
717 }
718 restore_uid();
719 fclose(f);
720 key_free(found);
539af7f5 721 if (!found_key)
722 debug2("key not found");
a306f2dd 723 return found_key;
724}
8002af61 725
96a7b0cc 726/* check whether given key is in .ssh/authorized_keys* */
1853d1ef 727int
96a7b0cc 728user_key_allowed(struct passwd *pw, Key *key)
729{
730 int success;
731 char *file;
732
733 file = authorized_keys_file(pw);
734 success = user_key_allowed2(pw, key, file);
735 xfree(file);
736 if (success)
737 return success;
738
739 /* try suffix "2" for backward compat, too */
740 file = authorized_keys_file2(pw);
741 success = user_key_allowed2(pw, key, file);
742 xfree(file);
743 return success;
744}
745
8002af61 746/* return 1 if given hostkey is allowed */
1853d1ef 747int
57a5edd8 748hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
8002af61 749 Key *key)
750{
8002af61 751 const char *resolvedname, *ipaddr, *lookup;
17a3011c 752 HostStatus host_status;
753 int len;
8002af61 754
bf4c5edc 755 resolvedname = get_canonical_hostname(options.verify_reverse_mapping);
8002af61 756 ipaddr = get_remote_ipaddr();
757
f98c3421 758 debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
759 chost, resolvedname, ipaddr);
8002af61 760
761 if (options.hostbased_uses_name_from_packet_only) {
762 if (auth_rhosts2(pw, cuser, chost, chost) == 0)
763 return 0;
764 lookup = chost;
765 } else {
f98c3421 766 if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
767 debug2("stripping trailing dot from chost %s", chost);
768 chost[len - 1] = '\0';
769 }
8002af61 770 if (strcasecmp(resolvedname, chost) != 0)
771 log("userauth_hostbased mismatch: "
772 "client sends %s, but we resolve %s to %s",
773 chost, ipaddr, resolvedname);
774 if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
775 return 0;
776 lookup = resolvedname;
777 }
778 debug2("userauth_hostbased: access allowed by auth_rhosts2");
779
d0c8ca5c 780 host_status = check_key_in_hostfiles(pw, key, lookup,
781 _PATH_SSH_SYSTEM_HOSTFILE,
73473230 782 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
d0c8ca5c 783
784 /* backward compat if no key has been found. */
785 if (host_status == HOST_NEW)
786 host_status = check_key_in_hostfiles(pw, key, lookup,
787 _PATH_SSH_SYSTEM_HOSTFILE2,
73473230 788 options.ignore_user_known_hosts ? NULL :
789 _PATH_SSH_USER_HOSTFILE2);
8002af61 790
8002af61 791 return (host_status == HOST_OK);
792}
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