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3c0ef626 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.
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 */
24
25#include "includes.h"
1e608e42 26RCSID("$OpenBSD: auth2.c,v 1.85 2002/02/24 19:14:59 markus Exp $");
3c0ef626 27
28#include <openssl/evp.h>
29
30#include "ssh2.h"
a2d82e42 31#include "ssh1.h"
3c0ef626 32#include "xmalloc.h"
33#include "rsa.h"
34#include "sshpty.h"
35#include "packet.h"
36#include "buffer.h"
37#include "log.h"
38#include "servconf.h"
39#include "compat.h"
40#include "channels.h"
41#include "bufaux.h"
42#include "auth.h"
43#include "session.h"
44#include "dispatch.h"
45#include "key.h"
46#include "cipher.h"
47#include "kex.h"
48#include "pathnames.h"
49#include "uidswap.h"
50#include "auth-options.h"
51#include "misc.h"
52#include "hostfile.h"
53#include "canohost.h"
54#include "match.h"
55
5598e598 56#ifdef GSSAPI
57#include "ssh-gss.h"
58#endif
59
3c0ef626 60/* import */
61extern ServerOptions options;
62extern u_char *session_id2;
63extern int session_id2_len;
64
65static Authctxt *x_authctxt = NULL;
66static int one = 1;
67
68typedef struct Authmethod Authmethod;
69struct Authmethod {
70 char *name;
71 int (*userauth)(Authctxt *authctxt);
72 int *enabled;
73};
74
75/* protocol */
76
1e608e42 77static void input_service_request(int, u_int32_t, void *);
78static void input_userauth_request(int, u_int32_t, void *);
3c0ef626 79
80/* helper */
81static Authmethod *authmethod_lookup(const char *);
82static char *authmethods_get(void);
83static int user_key_allowed(struct passwd *, Key *);
84static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
85
86/* auth */
87static void userauth_banner(void);
88static int userauth_none(Authctxt *);
89static int userauth_passwd(Authctxt *);
90static int userauth_pubkey(Authctxt *);
91static int userauth_hostbased(Authctxt *);
92static int userauth_kbdint(Authctxt *);
93
5598e598 94#ifdef GSSAPI
95int userauth_external(Authctxt *authctxt);
96int userauth_gssapi(Authctxt *authctxt);
97#endif
98
3c0ef626 99Authmethod authmethods[] = {
100 {"none",
101 userauth_none,
102 &one},
5598e598 103#ifdef GSSAPI
104 {"external-keyx",
105 userauth_external,
106 &options.gss_authentication},
107 {"gssapi",
108 userauth_gssapi,
109 &options.gss_authentication},
110#endif
3c0ef626 111 {"publickey",
112 userauth_pubkey,
113 &options.pubkey_authentication},
114 {"password",
115 userauth_passwd,
116 &options.password_authentication},
117 {"keyboard-interactive",
118 userauth_kbdint,
119 &options.kbd_interactive_authentication},
120 {"hostbased",
121 userauth_hostbased,
122 &options.hostbased_authentication},
123 {NULL, NULL, NULL}
124};
125
126/*
127 * loop until authctxt->success == TRUE
128 */
129
130void
1e608e42 131do_authentication2(void)
3c0ef626 132{
133 Authctxt *authctxt = authctxt_new();
134
135 x_authctxt = authctxt; /*XXX*/
136
137 /* challenge-response is implemented via keyboard interactive */
138 if (options.challenge_response_authentication)
139 options.kbd_interactive_authentication = 1;
140 if (options.pam_authentication_via_kbd_int)
141 options.kbd_interactive_authentication = 1;
142
1e608e42 143 dispatch_init(&dispatch_protocol_error);
3c0ef626 144 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
145 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
146 do_authenticated(authctxt);
147}
148
149static void
1e608e42 150input_service_request(int type, u_int32_t seq, void *ctxt)
3c0ef626 151{
152 Authctxt *authctxt = ctxt;
153 u_int len;
154 int accept = 0;
155 char *service = packet_get_string(&len);
1e608e42 156 packet_check_eom();
3c0ef626 157
158 if (authctxt == NULL)
159 fatal("input_service_request: no authctxt");
160
161 if (strcmp(service, "ssh-userauth") == 0) {
162 if (!authctxt->success) {
163 accept = 1;
164 /* now we can handle user-auth requests */
165 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
166 }
167 }
168 /* XXX all other service requests are denied */
169
170 if (accept) {
171 packet_start(SSH2_MSG_SERVICE_ACCEPT);
172 packet_put_cstring(service);
173 packet_send();
174 packet_write_wait();
175 } else {
176 debug("bad service request %s", service);
177 packet_disconnect("bad service request %s", service);
178 }
179 xfree(service);
180}
181
182static void
1e608e42 183input_userauth_request(int type, u_int32_t seq, void *ctxt)
3c0ef626 184{
185 Authctxt *authctxt = ctxt;
186 Authmethod *m = NULL;
187 char *user, *service, *method, *style = NULL;
188 int authenticated = 0;
189
190 if (authctxt == NULL)
191 fatal("input_userauth_request: no authctxt");
192
193 user = packet_get_string(NULL);
194 service = packet_get_string(NULL);
195 method = packet_get_string(NULL);
196 debug("userauth-request for user %s service %s method %s", user, service, method);
197 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
198
199 if ((style = strchr(user, ':')) != NULL)
200 *style++ = 0;
201
202 if (authctxt->attempt++ == 0) {
203 /* setup auth context */
204 struct passwd *pw = NULL;
205 pw = getpwnam(user);
206 if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
207 authctxt->pw = pwcopy(pw);
208 authctxt->valid = 1;
209 debug2("input_userauth_request: setting up authctxt for %s", user);
210#ifdef USE_PAM
211 start_pam(pw->pw_name);
212#endif
213 } else {
214 log("input_userauth_request: illegal user %s", user);
215#ifdef USE_PAM
216 start_pam("NOUSER");
217#endif
218 }
219 setproctitle("%s", pw ? user : "unknown");
220 authctxt->user = xstrdup(user);
221 authctxt->service = xstrdup(service);
222 authctxt->style = style ? xstrdup(style) : NULL;
223 } else if (strcmp(user, authctxt->user) != 0 ||
224 strcmp(service, authctxt->service) != 0) {
225 packet_disconnect("Change of username or service not allowed: "
226 "(%s,%s) -> (%s,%s)",
227 authctxt->user, authctxt->service, user, service);
228 }
229 /* reset state */
1e608e42 230 auth2_challenge_stop(authctxt);
5598e598 231
232#ifdef GSSAPI
1e608e42 233 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
234 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
5598e598 235#endif
236
3c0ef626 237 authctxt->postponed = 0;
3c0ef626 238
239 /* try to authenticate user */
240 m = authmethod_lookup(method);
241 if (m != NULL) {
242 debug2("input_userauth_request: try method %s", method);
243 authenticated = m->userauth(authctxt);
244 }
245 userauth_finish(authctxt, authenticated, method);
246
247 xfree(service);
248 xfree(user);
249 xfree(method);
250}
251
252void
253userauth_finish(Authctxt *authctxt, int authenticated, char *method)
254{
255 char *methods;
256
257 if (!authctxt->valid && authenticated)
258 fatal("INTERNAL ERROR: authenticated invalid user %s",
259 authctxt->user);
260
261 /* Special handling for root */
262 if (authenticated && authctxt->pw->pw_uid == 0 &&
263 !auth_root_allowed(method))
264 authenticated = 0;
265
266#ifdef USE_PAM
267 if (authenticated && authctxt->user && !do_pam_account(authctxt->user,
268 NULL))
269 authenticated = 0;
270#endif /* USE_PAM */
271
272 /* Log before sending the reply */
a2d82e42 273 if (!compat20)
274 auth_log(authctxt, authenticated, method, " ssh1");
275 else
3c0ef626 276 auth_log(authctxt, authenticated, method, " ssh2");
277
278 if (authctxt->postponed)
279 return;
280
281 /* XXX todo: check if multiple auth methods are needed */
282 if (authenticated == 1) {
283 /* turn off userauth */
1e608e42 284 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
a2d82e42 285 if (!compat20)
286 packet_start(SSH_SMSG_SUCCESS);
287 else
3c0ef626 288 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
289 packet_send();
290 packet_write_wait();
291 /* now we can break out */
292 authctxt->success = 1;
293 } else {
294 if (authctxt->failures++ > AUTH_FAIL_MAX) {
295#ifdef WITH_AIXAUTHENTICATE
296 loginfailed(authctxt->user,
1e608e42 297 get_canonical_hostname(options.verify_reverse_mapping),
3c0ef626 298 "ssh");
299#endif /* WITH_AIXAUTHENTICATE */
300 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
301 }
302 methods = authmethods_get();
a2d82e42 303 if (!compat20)
304 packet_disconnect("GSSAPI authentication failed");
305 else
3c0ef626 306 packet_start(SSH2_MSG_USERAUTH_FAILURE);
307 packet_put_cstring(methods);
308 packet_put_char(0); /* XXX partial success, unused */
309 packet_send();
310 packet_write_wait();
311 xfree(methods);
312 }
313}
314
315static void
316userauth_banner(void)
317{
318 struct stat st;
319 char *banner = NULL;
320 off_t len, n;
321 int fd;
322
323 if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
324 return;
325 if ((fd = open(options.banner, O_RDONLY)) < 0)
326 return;
327 if (fstat(fd, &st) < 0)
328 goto done;
329 len = st.st_size;
330 banner = xmalloc(len + 1);
331 if ((n = read(fd, banner, len)) < 0)
332 goto done;
333 banner[n] = '\0';
334 packet_start(SSH2_MSG_USERAUTH_BANNER);
335 packet_put_cstring(banner);
336 packet_put_cstring(""); /* language, unused */
337 packet_send();
338 debug("userauth_banner: sent");
339done:
340 if (banner)
341 xfree(banner);
342 close(fd);
343 return;
344}
345
346static int
347userauth_none(Authctxt *authctxt)
348{
349 /* disable method "none", only allowed one time */
350 Authmethod *m = authmethod_lookup("none");
351 if (m != NULL)
352 m->enabled = NULL;
1e608e42 353 packet_check_eom();
3c0ef626 354 userauth_banner();
355
356 if (authctxt->valid == 0)
357 return(0);
358
359#ifdef HAVE_CYGWIN
1e608e42 360 if (check_nt_auth(1, authctxt->pw) == 0)
3c0ef626 361 return(0);
362#endif
363#ifdef USE_PAM
364 return auth_pam_password(authctxt->pw, "");
365#elif defined(HAVE_OSF_SIA)
366 return 0;
367#else /* !HAVE_OSF_SIA && !USE_PAM */
368 return auth_password(authctxt, "");
369#endif /* USE_PAM */
370}
371
372static int
373userauth_passwd(Authctxt *authctxt)
374{
375 char *password;
376 int authenticated = 0;
377 int change;
378 u_int len;
379 change = packet_get_char();
380 if (change)
381 log("password change not supported");
382 password = packet_get_string(&len);
1e608e42 383 packet_check_eom();
3c0ef626 384 if (authctxt->valid &&
385#ifdef HAVE_CYGWIN
1e608e42 386 check_nt_auth(1, authctxt->pw) &&
3c0ef626 387#endif
388#ifdef USE_PAM
389 auth_pam_password(authctxt->pw, password) == 1)
390#elif defined(HAVE_OSF_SIA)
391 auth_sia_password(authctxt->user, password) == 1)
392#else /* !USE_PAM && !HAVE_OSF_SIA */
393 auth_password(authctxt, password) == 1)
394#endif /* USE_PAM */
395 authenticated = 1;
396 memset(password, 0, len);
397 xfree(password);
398 return authenticated;
399}
400
401static int
402userauth_kbdint(Authctxt *authctxt)
403{
404 int authenticated = 0;
405 char *lang, *devs;
406
407 lang = packet_get_string(NULL);
408 devs = packet_get_string(NULL);
1e608e42 409 packet_check_eom();
3c0ef626 410
411 debug("keyboard-interactive devs %s", devs);
412
413 if (options.challenge_response_authentication)
414 authenticated = auth2_challenge(authctxt, devs);
415
416#ifdef USE_PAM
417 if (authenticated == 0 && options.pam_authentication_via_kbd_int)
418 authenticated = auth2_pam(authctxt);
419#endif
420 xfree(devs);
421 xfree(lang);
422#ifdef HAVE_CYGWIN
1e608e42 423 if (check_nt_auth(0, authctxt->pw) == 0)
3c0ef626 424 return(0);
425#endif
426 return authenticated;
427}
428
429static int
430userauth_pubkey(Authctxt *authctxt)
431{
432 Buffer b;
1e608e42 433 Key *key = NULL;
434 char *pkalg;
435 u_char *pkblob, *sig;
3c0ef626 436 u_int alen, blen, slen;
437 int have_sig, pktype;
438 int authenticated = 0;
439
440 if (!authctxt->valid) {
441 debug2("userauth_pubkey: disabled because of invalid user");
442 return 0;
443 }
444 have_sig = packet_get_char();
445 if (datafellows & SSH_BUG_PKAUTH) {
446 debug2("userauth_pubkey: SSH_BUG_PKAUTH");
447 /* no explicit pkalg given */
448 pkblob = packet_get_string(&blen);
449 buffer_init(&b);
450 buffer_append(&b, pkblob, blen);
451 /* so we have to extract the pkalg from the pkblob */
452 pkalg = buffer_get_string(&b, &alen);
453 buffer_free(&b);
454 } else {
455 pkalg = packet_get_string(&alen);
456 pkblob = packet_get_string(&blen);
457 }
458 pktype = key_type_from_name(pkalg);
459 if (pktype == KEY_UNSPEC) {
460 /* this is perfectly legal */
1e608e42 461 log("userauth_pubkey: unsupported public key algorithm: %s",
462 pkalg);
463 goto done;
3c0ef626 464 }
465 key = key_from_blob(pkblob, blen);
1e608e42 466 if (key == NULL) {
467 error("userauth_pubkey: cannot decode key: %s", pkalg);
468 goto done;
469 }
470 if (key->type != pktype) {
471 error("userauth_pubkey: type mismatch for decoded key "
472 "(received %d, expected %d)", key->type, pktype);
473 goto done;
474 }
475 if (have_sig) {
476 sig = packet_get_string(&slen);
477 packet_check_eom();
478 buffer_init(&b);
479 if (datafellows & SSH_OLD_SESSIONID) {
480 buffer_append(&b, session_id2, session_id2_len);
481 } else {
482 buffer_put_string(&b, session_id2, session_id2_len);
483 }
484 /* reconstruct packet */
485 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
486 buffer_put_cstring(&b, authctxt->user);
487 buffer_put_cstring(&b,
488 datafellows & SSH_BUG_PKSERVICE ?
489 "ssh-userauth" :
490 authctxt->service);
491 if (datafellows & SSH_BUG_PKAUTH) {
492 buffer_put_char(&b, have_sig);
493 } else {
494 buffer_put_cstring(&b, "publickey");
495 buffer_put_char(&b, have_sig);
496 buffer_put_cstring(&b, pkalg);
497 }
498 buffer_put_string(&b, pkblob, blen);
3c0ef626 499#ifdef DEBUG_PK
1e608e42 500 buffer_dump(&b);
3c0ef626 501#endif
1e608e42 502 /* test for correct signature */
503 if (user_key_allowed(authctxt->pw, key) &&
504 key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
505 authenticated = 1;
506 buffer_clear(&b);
507 xfree(sig);
508 } else {
509 debug("test whether pkalg/pkblob are acceptable");
510 packet_check_eom();
511
512 /* XXX fake reply and always send PK_OK ? */
513 /*
514 * XXX this allows testing whether a user is allowed
515 * to login: if you happen to have a valid pubkey this
516 * message is sent. the message is NEVER sent at all
517 * if a user is not allowed to login. is this an
518 * issue? -markus
519 */
520 if (user_key_allowed(authctxt->pw, key)) {
521 packet_start(SSH2_MSG_USERAUTH_PK_OK);
522 packet_put_string(pkalg, alen);
523 packet_put_string(pkblob, blen);
524 packet_send();
525 packet_write_wait();
526 authctxt->postponed = 1;
3c0ef626 527 }
3c0ef626 528 }
1e608e42 529 if (authenticated != 1)
530 auth_clear_options();
531done:
3c0ef626 532 debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1e608e42 533 if (key != NULL)
534 key_free(key);
3c0ef626 535 xfree(pkalg);
536 xfree(pkblob);
537#ifdef HAVE_CYGWIN
1e608e42 538 if (check_nt_auth(0, authctxt->pw) == 0)
3c0ef626 539 return(0);
540#endif
541 return authenticated;
542}
543
544static int
545userauth_hostbased(Authctxt *authctxt)
546{
547 Buffer b;
1e608e42 548 Key *key = NULL;
549 char *pkalg, *cuser, *chost, *service;
550 u_char *pkblob, *sig;
3c0ef626 551 u_int alen, blen, slen;
552 int pktype;
553 int authenticated = 0;
554
555 if (!authctxt->valid) {
556 debug2("userauth_hostbased: disabled because of invalid user");
557 return 0;
558 }
559 pkalg = packet_get_string(&alen);
560 pkblob = packet_get_string(&blen);
561 chost = packet_get_string(NULL);
562 cuser = packet_get_string(NULL);
563 sig = packet_get_string(&slen);
564
565 debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
566 cuser, chost, pkalg, slen);
567#ifdef DEBUG_PK
568 debug("signature:");
569 buffer_init(&b);
570 buffer_append(&b, sig, slen);
571 buffer_dump(&b);
572 buffer_free(&b);
573#endif
574 pktype = key_type_from_name(pkalg);
575 if (pktype == KEY_UNSPEC) {
576 /* this is perfectly legal */
577 log("userauth_hostbased: unsupported "
578 "public key algorithm: %s", pkalg);
579 goto done;
580 }
581 key = key_from_blob(pkblob, blen);
582 if (key == NULL) {
1e608e42 583 error("userauth_hostbased: cannot decode key: %s", pkalg);
584 goto done;
585 }
586 if (key->type != pktype) {
587 error("userauth_hostbased: type mismatch for decoded key "
588 "(received %d, expected %d)", key->type, pktype);
3c0ef626 589 goto done;
590 }
591 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
592 authctxt->service;
593 buffer_init(&b);
594 buffer_put_string(&b, session_id2, session_id2_len);
595 /* reconstruct packet */
596 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
597 buffer_put_cstring(&b, authctxt->user);
598 buffer_put_cstring(&b, service);
599 buffer_put_cstring(&b, "hostbased");
600 buffer_put_string(&b, pkalg, alen);
601 buffer_put_string(&b, pkblob, blen);
602 buffer_put_cstring(&b, chost);
603 buffer_put_cstring(&b, cuser);
604#ifdef DEBUG_PK
605 buffer_dump(&b);
606#endif
607 /* test for allowed key and correct signature */
608 if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
609 key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
610 authenticated = 1;
611
612 buffer_clear(&b);
3c0ef626 613done:
614 debug2("userauth_hostbased: authenticated %d", authenticated);
1e608e42 615 if (key != NULL)
616 key_free(key);
3c0ef626 617 xfree(pkalg);
618 xfree(pkblob);
619 xfree(cuser);
620 xfree(chost);
621 xfree(sig);
622 return authenticated;
623}
624
625/* get current user */
626
627struct passwd*
628auth_get_user(void)
629{
630 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
631}
632
633#define DELIM ","
634
635static char *
636authmethods_get(void)
637{
638 Authmethod *method = NULL;
1e608e42 639 Buffer b;
3c0ef626 640 char *list;
641
1e608e42 642 buffer_init(&b);
3c0ef626 643 for (method = authmethods; method->name != NULL; method++) {
644 if (strcmp(method->name, "none") == 0)
645 continue;
646 if (method->enabled != NULL && *(method->enabled) != 0) {
1e608e42 647 if (buffer_len(&b) > 0)
648 buffer_append(&b, ",", 1);
649 buffer_append(&b, method->name, strlen(method->name));
3c0ef626 650 }
651 }
1e608e42 652 buffer_append(&b, "\0", 1);
653 list = xstrdup(buffer_ptr(&b));
654 buffer_free(&b);
3c0ef626 655 return list;
656}
657
658static Authmethod *
659authmethod_lookup(const char *name)
660{
661 Authmethod *method = NULL;
662 if (name != NULL)
663 for (method = authmethods; method->name != NULL; method++)
664 if (method->enabled != NULL &&
665 *(method->enabled) != 0 &&
666 strcmp(name, method->name) == 0)
667 return method;
668 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
669 return NULL;
670}
671
672/* return 1 if user allows given key */
673static int
674user_key_allowed2(struct passwd *pw, Key *key, char *file)
675{
676 char line[8192];
677 int found_key = 0;
678 FILE *f;
679 u_long linenum = 0;
680 struct stat st;
681 Key *found;
1e608e42 682 char *fp;
3c0ef626 683
684 if (pw == NULL)
685 return 0;
686
687 /* Temporarily use the user's uid. */
688 temporarily_use_uid(pw);
689
690 debug("trying public key file %s", file);
691
692 /* Fail quietly if file does not exist */
693 if (stat(file, &st) < 0) {
694 /* Restore the privileged uid. */
695 restore_uid();
696 return 0;
697 }
698 /* Open the file containing the authorized keys. */
699 f = fopen(file, "r");
700 if (!f) {
701 /* Restore the privileged uid. */
702 restore_uid();
703 return 0;
704 }
705 if (options.strict_modes &&
706 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
707 fclose(f);
708 log("Authentication refused: %s", line);
709 restore_uid();
710 return 0;
711 }
712
713 found_key = 0;
714 found = key_new(key->type);
715
716 while (fgets(line, sizeof(line), f)) {
717 char *cp, *options = NULL;
718 linenum++;
719 /* Skip leading whitespace, empty and comment lines. */
720 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
721 ;
722 if (!*cp || *cp == '\n' || *cp == '#')
723 continue;
724
725 if (key_read(found, &cp) != 1) {
726 /* no key? check if there are options for this key */
727 int quoted = 0;
728 debug2("user_key_allowed: check options: '%s'", cp);
729 options = cp;
730 for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
731 if (*cp == '\\' && cp[1] == '"')
732 cp++; /* Skip both */
733 else if (*cp == '"')
734 quoted = !quoted;
735 }
736 /* Skip remaining whitespace. */
737 for (; *cp == ' ' || *cp == '\t'; cp++)
738 ;
739 if (key_read(found, &cp) != 1) {
740 debug2("user_key_allowed: advance: '%s'", cp);
741 /* still no key? advance to next line*/
742 continue;
743 }
744 }
745 if (key_equal(found, key) &&
746 auth_parse_options(pw, options, file, linenum) == 1) {
747 found_key = 1;
748 debug("matching key found: file %s, line %lu",
749 file, linenum);
1e608e42 750 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
751 verbose("Found matching %s key: %s",
752 key_type(found), fp);
753 xfree(fp);
3c0ef626 754 break;
755 }
756 }
757 restore_uid();
758 fclose(f);
759 key_free(found);
760 if (!found_key)
761 debug2("key not found");
762 return found_key;
763}
764
765/* check whether given key is in .ssh/authorized_keys* */
766static int
767user_key_allowed(struct passwd *pw, Key *key)
768{
769 int success;
770 char *file;
771
772 file = authorized_keys_file(pw);
773 success = user_key_allowed2(pw, key, file);
774 xfree(file);
775 if (success)
776 return success;
777
778 /* try suffix "2" for backward compat, too */
779 file = authorized_keys_file2(pw);
780 success = user_key_allowed2(pw, key, file);
781 xfree(file);
782 return success;
783}
784
785/* return 1 if given hostkey is allowed */
786static int
787hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
788 Key *key)
789{
790 const char *resolvedname, *ipaddr, *lookup;
1e608e42 791 HostStatus host_status;
792 int len;
3c0ef626 793
1e608e42 794 resolvedname = get_canonical_hostname(options.verify_reverse_mapping);
3c0ef626 795 ipaddr = get_remote_ipaddr();
796
797 debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
798 chost, resolvedname, ipaddr);
799
800 if (options.hostbased_uses_name_from_packet_only) {
801 if (auth_rhosts2(pw, cuser, chost, chost) == 0)
802 return 0;
803 lookup = chost;
804 } else {
805 if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
806 debug2("stripping trailing dot from chost %s", chost);
807 chost[len - 1] = '\0';
808 }
809 if (strcasecmp(resolvedname, chost) != 0)
810 log("userauth_hostbased mismatch: "
811 "client sends %s, but we resolve %s to %s",
812 chost, ipaddr, resolvedname);
813 if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
814 return 0;
815 lookup = resolvedname;
816 }
817 debug2("userauth_hostbased: access allowed by auth_rhosts2");
818
819 host_status = check_key_in_hostfiles(pw, key, lookup,
820 _PATH_SSH_SYSTEM_HOSTFILE,
821 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
822
823 /* backward compat if no key has been found. */
824 if (host_status == HOST_NEW)
825 host_status = check_key_in_hostfiles(pw, key, lookup,
826 _PATH_SSH_SYSTEM_HOSTFILE2,
827 options.ignore_user_known_hosts ? NULL :
828 _PATH_SSH_USER_HOSTFILE2);
829
830 return (host_status == HOST_OK);
831}
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