xref: /freebsd/crypto/openssh/auth.c (revision 57718be8fa0bd5edc11ab9a72e68cc71982939a6)
1 /* $OpenBSD: auth.c,v 1.103 2013/05/19 02:42:42 djm Exp $ */
2 /* $FreeBSD$ */
3 /*
4  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include "includes.h"
28 __RCSID("$FreeBSD$");
29 
30 #include <sys/types.h>
31 #include <sys/stat.h>
32 #include <sys/param.h>
33 
34 #include <netinet/in.h>
35 
36 #include <errno.h>
37 #include <fcntl.h>
38 #ifdef HAVE_PATHS_H
39 # include <paths.h>
40 #endif
41 #include <pwd.h>
42 #ifdef HAVE_LOGIN_H
43 #include <login.h>
44 #endif
45 #ifdef USE_SHADOW
46 #include <shadow.h>
47 #endif
48 #ifdef HAVE_LIBGEN_H
49 #include <libgen.h>
50 #endif
51 #include <stdarg.h>
52 #include <stdio.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 #include "xmalloc.h"
57 #include "match.h"
58 #include "groupaccess.h"
59 #include "log.h"
60 #include "buffer.h"
61 #include "servconf.h"
62 #include "key.h"
63 #include "hostfile.h"
64 #include "auth.h"
65 #include "auth-options.h"
66 #include "canohost.h"
67 #include "uidswap.h"
68 #include "misc.h"
69 #include "packet.h"
70 #include "loginrec.h"
71 #ifdef GSSAPI
72 #include "ssh-gss.h"
73 #endif
74 #include "authfile.h"
75 #include "monitor_wrap.h"
76 #include "krl.h"
77 #include "compat.h"
78 
79 /* import */
80 extern ServerOptions options;
81 extern int use_privsep;
82 extern Buffer loginmsg;
83 extern struct passwd *privsep_pw;
84 
85 /* Debugging messages */
86 Buffer auth_debug;
87 int auth_debug_init;
88 
89 /*
90  * Check if the user is allowed to log in via ssh. If user is listed
91  * in DenyUsers or one of user's groups is listed in DenyGroups, false
92  * will be returned. If AllowUsers isn't empty and user isn't listed
93  * there, or if AllowGroups isn't empty and one of user's groups isn't
94  * listed there, false will be returned.
95  * If the user's shell is not executable, false will be returned.
96  * Otherwise true is returned.
97  */
98 int
99 allowed_user(struct passwd * pw)
100 {
101 	struct stat st;
102 	const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
103 	u_int i;
104 #ifdef USE_SHADOW
105 	struct spwd *spw = NULL;
106 #endif
107 
108 	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
109 	if (!pw || !pw->pw_name)
110 		return 0;
111 
112 #ifdef USE_SHADOW
113 	if (!options.use_pam)
114 		spw = getspnam(pw->pw_name);
115 #ifdef HAS_SHADOW_EXPIRE
116 	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
117 		return 0;
118 #endif /* HAS_SHADOW_EXPIRE */
119 #endif /* USE_SHADOW */
120 
121 	/* grab passwd field for locked account check */
122 	passwd = pw->pw_passwd;
123 #ifdef USE_SHADOW
124 	if (spw != NULL)
125 #ifdef USE_LIBIAF
126 		passwd = get_iaf_password(pw);
127 #else
128 		passwd = spw->sp_pwdp;
129 #endif /* USE_LIBIAF */
130 #endif
131 
132 	/* check for locked account */
133 	if (!options.use_pam && passwd && *passwd) {
134 		int locked = 0;
135 
136 #ifdef LOCKED_PASSWD_STRING
137 		if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
138 			 locked = 1;
139 #endif
140 #ifdef LOCKED_PASSWD_PREFIX
141 		if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
142 		    strlen(LOCKED_PASSWD_PREFIX)) == 0)
143 			 locked = 1;
144 #endif
145 #ifdef LOCKED_PASSWD_SUBSTR
146 		if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
147 			locked = 1;
148 #endif
149 #ifdef USE_LIBIAF
150 		free((void *) passwd);
151 #endif /* USE_LIBIAF */
152 		if (locked) {
153 			logit("User %.100s not allowed because account is locked",
154 			    pw->pw_name);
155 			return 0;
156 		}
157 	}
158 
159 	/*
160 	 * Deny if shell does not exist or is not executable unless we
161 	 * are chrooting.
162 	 */
163 	if (options.chroot_directory == NULL ||
164 	    strcasecmp(options.chroot_directory, "none") == 0) {
165 		char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
166 		    _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
167 
168 		if (stat(shell, &st) != 0) {
169 			logit("User %.100s not allowed because shell %.100s "
170 			    "does not exist", pw->pw_name, shell);
171 			free(shell);
172 			return 0;
173 		}
174 		if (S_ISREG(st.st_mode) == 0 ||
175 		    (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
176 			logit("User %.100s not allowed because shell %.100s "
177 			    "is not executable", pw->pw_name, shell);
178 			free(shell);
179 			return 0;
180 		}
181 		free(shell);
182 	}
183 
184 	if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
185 	    options.num_deny_groups > 0 || options.num_allow_groups > 0) {
186 		hostname = get_canonical_hostname(options.use_dns);
187 		ipaddr = get_remote_ipaddr();
188 	}
189 
190 	/* Return false if user is listed in DenyUsers */
191 	if (options.num_deny_users > 0) {
192 		for (i = 0; i < options.num_deny_users; i++)
193 			if (match_user(pw->pw_name, hostname, ipaddr,
194 			    options.deny_users[i])) {
195 				logit("User %.100s from %.100s not allowed "
196 				    "because listed in DenyUsers",
197 				    pw->pw_name, hostname);
198 				return 0;
199 			}
200 	}
201 	/* Return false if AllowUsers isn't empty and user isn't listed there */
202 	if (options.num_allow_users > 0) {
203 		for (i = 0; i < options.num_allow_users; i++)
204 			if (match_user(pw->pw_name, hostname, ipaddr,
205 			    options.allow_users[i]))
206 				break;
207 		/* i < options.num_allow_users iff we break for loop */
208 		if (i >= options.num_allow_users) {
209 			logit("User %.100s from %.100s not allowed because "
210 			    "not listed in AllowUsers", pw->pw_name, hostname);
211 			return 0;
212 		}
213 	}
214 	if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
215 		/* Get the user's group access list (primary and supplementary) */
216 		if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
217 			logit("User %.100s from %.100s not allowed because "
218 			    "not in any group", pw->pw_name, hostname);
219 			return 0;
220 		}
221 
222 		/* Return false if one of user's groups is listed in DenyGroups */
223 		if (options.num_deny_groups > 0)
224 			if (ga_match(options.deny_groups,
225 			    options.num_deny_groups)) {
226 				ga_free();
227 				logit("User %.100s from %.100s not allowed "
228 				    "because a group is listed in DenyGroups",
229 				    pw->pw_name, hostname);
230 				return 0;
231 			}
232 		/*
233 		 * Return false if AllowGroups isn't empty and one of user's groups
234 		 * isn't listed there
235 		 */
236 		if (options.num_allow_groups > 0)
237 			if (!ga_match(options.allow_groups,
238 			    options.num_allow_groups)) {
239 				ga_free();
240 				logit("User %.100s from %.100s not allowed "
241 				    "because none of user's groups are listed "
242 				    "in AllowGroups", pw->pw_name, hostname);
243 				return 0;
244 			}
245 		ga_free();
246 	}
247 
248 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
249 	if (!sys_auth_allowed_user(pw, &loginmsg))
250 		return 0;
251 #endif
252 
253 	/* We found no reason not to let this user try to log on... */
254 	return 1;
255 }
256 
257 void
258 auth_info(Authctxt *authctxt, const char *fmt, ...)
259 {
260 	va_list ap;
261         int i;
262 
263 	free(authctxt->info);
264 	authctxt->info = NULL;
265 
266 	va_start(ap, fmt);
267 	i = vasprintf(&authctxt->info, fmt, ap);
268 	va_end(ap);
269 
270 	if (i < 0 || authctxt->info == NULL)
271 		fatal("vasprintf failed");
272 }
273 
274 void
275 auth_log(Authctxt *authctxt, int authenticated, int partial,
276     const char *method, const char *submethod)
277 {
278 	void (*authlog) (const char *fmt,...) = verbose;
279 	char *authmsg;
280 
281 	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
282 		return;
283 
284 	/* Raise logging level */
285 	if (authenticated == 1 ||
286 	    !authctxt->valid ||
287 	    authctxt->failures >= options.max_authtries / 2 ||
288 	    strcmp(method, "password") == 0)
289 		authlog = logit;
290 
291 	if (authctxt->postponed)
292 		authmsg = "Postponed";
293 	else if (partial)
294 		authmsg = "Partial";
295 	else
296 		authmsg = authenticated ? "Accepted" : "Failed";
297 
298 	authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
299 	    authmsg,
300 	    method,
301 	    submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
302 	    authctxt->valid ? "" : "invalid user ",
303 	    authctxt->user,
304 	    get_remote_ipaddr(),
305 	    get_remote_port(),
306 	    compat20 ? "ssh2" : "ssh1",
307 	    authctxt->info != NULL ? ": " : "",
308 	    authctxt->info != NULL ? authctxt->info : "");
309 	free(authctxt->info);
310 	authctxt->info = NULL;
311 
312 #ifdef CUSTOM_FAILED_LOGIN
313 	if (authenticated == 0 && !authctxt->postponed &&
314 	    (strcmp(method, "password") == 0 ||
315 	    strncmp(method, "keyboard-interactive", 20) == 0 ||
316 	    strcmp(method, "challenge-response") == 0))
317 		record_failed_login(authctxt->user,
318 		    get_canonical_hostname(options.use_dns), "ssh");
319 # ifdef WITH_AIXAUTHENTICATE
320 	if (authenticated)
321 		sys_auth_record_login(authctxt->user,
322 		    get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
323 # endif
324 #endif
325 #ifdef SSH_AUDIT_EVENTS
326 	if (authenticated == 0 && !authctxt->postponed)
327 		audit_event(audit_classify_auth(method));
328 #endif
329 }
330 
331 /*
332  * Check whether root logins are disallowed.
333  */
334 int
335 auth_root_allowed(const char *method)
336 {
337 	switch (options.permit_root_login) {
338 	case PERMIT_YES:
339 		return 1;
340 	case PERMIT_NO_PASSWD:
341 		if (strcmp(method, "password") != 0)
342 			return 1;
343 		break;
344 	case PERMIT_FORCED_ONLY:
345 		if (forced_command) {
346 			logit("Root login accepted for forced command.");
347 			return 1;
348 		}
349 		break;
350 	}
351 	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
352 	return 0;
353 }
354 
355 
356 /*
357  * Given a template and a passwd structure, build a filename
358  * by substituting % tokenised options. Currently, %% becomes '%',
359  * %h becomes the home directory and %u the username.
360  *
361  * This returns a buffer allocated by xmalloc.
362  */
363 char *
364 expand_authorized_keys(const char *filename, struct passwd *pw)
365 {
366 	char *file, ret[MAXPATHLEN];
367 	int i;
368 
369 	file = percent_expand(filename, "h", pw->pw_dir,
370 	    "u", pw->pw_name, (char *)NULL);
371 
372 	/*
373 	 * Ensure that filename starts anchored. If not, be backward
374 	 * compatible and prepend the '%h/'
375 	 */
376 	if (*file == '/')
377 		return (file);
378 
379 	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
380 	if (i < 0 || (size_t)i >= sizeof(ret))
381 		fatal("expand_authorized_keys: path too long");
382 	free(file);
383 	return (xstrdup(ret));
384 }
385 
386 char *
387 authorized_principals_file(struct passwd *pw)
388 {
389 	if (options.authorized_principals_file == NULL ||
390 	    strcasecmp(options.authorized_principals_file, "none") == 0)
391 		return NULL;
392 	return expand_authorized_keys(options.authorized_principals_file, pw);
393 }
394 
395 /* return ok if key exists in sysfile or userfile */
396 HostStatus
397 check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
398     const char *sysfile, const char *userfile)
399 {
400 	char *user_hostfile;
401 	struct stat st;
402 	HostStatus host_status;
403 	struct hostkeys *hostkeys;
404 	const struct hostkey_entry *found;
405 
406 	hostkeys = init_hostkeys();
407 	load_hostkeys(hostkeys, host, sysfile);
408 	if (userfile != NULL) {
409 		user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
410 		if (options.strict_modes &&
411 		    (stat(user_hostfile, &st) == 0) &&
412 		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
413 		    (st.st_mode & 022) != 0)) {
414 			logit("Authentication refused for %.100s: "
415 			    "bad owner or modes for %.200s",
416 			    pw->pw_name, user_hostfile);
417 			auth_debug_add("Ignored %.200s: bad ownership or modes",
418 			    user_hostfile);
419 		} else {
420 			temporarily_use_uid(pw);
421 			load_hostkeys(hostkeys, host, user_hostfile);
422 			restore_uid();
423 		}
424 		free(user_hostfile);
425 	}
426 	host_status = check_key_in_hostkeys(hostkeys, key, &found);
427 	if (host_status == HOST_REVOKED)
428 		error("WARNING: revoked key for %s attempted authentication",
429 		    found->host);
430 	else if (host_status == HOST_OK)
431 		debug("%s: key for %s found at %s:%ld", __func__,
432 		    found->host, found->file, found->line);
433 	else
434 		debug("%s: key for host %s not found", __func__, host);
435 
436 	free_hostkeys(hostkeys);
437 
438 	return host_status;
439 }
440 
441 /*
442  * Check a given path for security. This is defined as all components
443  * of the path to the file must be owned by either the owner of
444  * of the file or root and no directories must be group or world writable.
445  *
446  * XXX Should any specific check be done for sym links ?
447  *
448  * Takes a file name, its stat information (preferably from fstat() to
449  * avoid races), the uid of the expected owner, their home directory and an
450  * error buffer plus max size as arguments.
451  *
452  * Returns 0 on success and -1 on failure
453  */
454 int
455 auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
456     uid_t uid, char *err, size_t errlen)
457 {
458 	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
459 	char *cp;
460 	int comparehome = 0;
461 	struct stat st;
462 
463 	if (realpath(name, buf) == NULL) {
464 		snprintf(err, errlen, "realpath %s failed: %s", name,
465 		    strerror(errno));
466 		return -1;
467 	}
468 	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
469 		comparehome = 1;
470 
471 	if (!S_ISREG(stp->st_mode)) {
472 		snprintf(err, errlen, "%s is not a regular file", buf);
473 		return -1;
474 	}
475 	if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
476 	    (stp->st_mode & 022) != 0) {
477 		snprintf(err, errlen, "bad ownership or modes for file %s",
478 		    buf);
479 		return -1;
480 	}
481 
482 	/* for each component of the canonical path, walking upwards */
483 	for (;;) {
484 		if ((cp = dirname(buf)) == NULL) {
485 			snprintf(err, errlen, "dirname() failed");
486 			return -1;
487 		}
488 		strlcpy(buf, cp, sizeof(buf));
489 
490 		if (stat(buf, &st) < 0 ||
491 		    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
492 		    (st.st_mode & 022) != 0) {
493 			snprintf(err, errlen,
494 			    "bad ownership or modes for directory %s", buf);
495 			return -1;
496 		}
497 
498 		/* If are past the homedir then we can stop */
499 		if (comparehome && strcmp(homedir, buf) == 0)
500 			break;
501 
502 		/*
503 		 * dirname should always complete with a "/" path,
504 		 * but we can be paranoid and check for "." too
505 		 */
506 		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
507 			break;
508 	}
509 	return 0;
510 }
511 
512 /*
513  * Version of secure_path() that accepts an open file descriptor to
514  * avoid races.
515  *
516  * Returns 0 on success and -1 on failure
517  */
518 static int
519 secure_filename(FILE *f, const char *file, struct passwd *pw,
520     char *err, size_t errlen)
521 {
522 	struct stat st;
523 
524 	/* check the open file to avoid races */
525 	if (fstat(fileno(f), &st) < 0) {
526 		snprintf(err, errlen, "cannot stat file %s: %s",
527 		    file, strerror(errno));
528 		return -1;
529 	}
530 	return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
531 }
532 
533 static FILE *
534 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
535     int log_missing, char *file_type)
536 {
537 	char line[1024];
538 	struct stat st;
539 	int fd;
540 	FILE *f;
541 
542 	if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
543 		if (log_missing || errno != ENOENT)
544 			debug("Could not open %s '%s': %s", file_type, file,
545 			   strerror(errno));
546 		return NULL;
547 	}
548 
549 	if (fstat(fd, &st) < 0) {
550 		close(fd);
551 		return NULL;
552 	}
553 	if (!S_ISREG(st.st_mode)) {
554 		logit("User %s %s %s is not a regular file",
555 		    pw->pw_name, file_type, file);
556 		close(fd);
557 		return NULL;
558 	}
559 	unset_nonblock(fd);
560 	if ((f = fdopen(fd, "r")) == NULL) {
561 		close(fd);
562 		return NULL;
563 	}
564 	if (strict_modes &&
565 	    secure_filename(f, file, pw, line, sizeof(line)) != 0) {
566 		fclose(f);
567 		logit("Authentication refused: %s", line);
568 		auth_debug_add("Ignored %s: %s", file_type, line);
569 		return NULL;
570 	}
571 
572 	return f;
573 }
574 
575 
576 FILE *
577 auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
578 {
579 	return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
580 }
581 
582 FILE *
583 auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
584 {
585 	return auth_openfile(file, pw, strict_modes, 0,
586 	    "authorized principals");
587 }
588 
589 struct passwd *
590 getpwnamallow(const char *user)
591 {
592 #ifdef HAVE_LOGIN_CAP
593 	extern login_cap_t *lc;
594 #ifdef BSD_AUTH
595 	auth_session_t *as;
596 #endif
597 #endif
598 	struct passwd *pw;
599 	struct connection_info *ci = get_connection_info(1, options.use_dns);
600 
601 	ci->user = user;
602 	parse_server_match_config(&options, ci);
603 
604 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
605 	aix_setauthdb(user);
606 #endif
607 
608 	pw = getpwnam(user);
609 
610 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
611 	aix_restoreauthdb();
612 #endif
613 #ifdef HAVE_CYGWIN
614 	/*
615 	 * Windows usernames are case-insensitive.  To avoid later problems
616 	 * when trying to match the username, the user is only allowed to
617 	 * login if the username is given in the same case as stored in the
618 	 * user database.
619 	 */
620 	if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
621 		logit("Login name %.100s does not match stored username %.100s",
622 		    user, pw->pw_name);
623 		pw = NULL;
624 	}
625 #endif
626 	if (pw == NULL) {
627 		logit("Invalid user %.100s from %.100s",
628 		    user, get_remote_ipaddr());
629 #ifdef CUSTOM_FAILED_LOGIN
630 		record_failed_login(user,
631 		    get_canonical_hostname(options.use_dns), "ssh");
632 #endif
633 #ifdef SSH_AUDIT_EVENTS
634 		audit_event(SSH_INVALID_USER);
635 #endif /* SSH_AUDIT_EVENTS */
636 		return (NULL);
637 	}
638 	if (!allowed_user(pw))
639 		return (NULL);
640 #ifdef HAVE_LOGIN_CAP
641 	if ((lc = login_getpwclass(pw)) == NULL) {
642 		debug("unable to get login class: %s", user);
643 		return (NULL);
644 	}
645 #ifdef BSD_AUTH
646 	if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
647 	    auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
648 		debug("Approval failure for %s", user);
649 		pw = NULL;
650 	}
651 	if (as != NULL)
652 		auth_close(as);
653 #endif
654 #endif
655 	if (pw != NULL)
656 		return (pwcopy(pw));
657 	return (NULL);
658 }
659 
660 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
661 int
662 auth_key_is_revoked(Key *key)
663 {
664 	char *key_fp;
665 
666 	if (options.revoked_keys_file == NULL)
667 		return 0;
668 	switch (ssh_krl_file_contains_key(options.revoked_keys_file, key)) {
669 	case 0:
670 		return 0;	/* Not revoked */
671 	case -2:
672 		break;		/* Not a KRL */
673 	default:
674 		goto revoked;
675 	}
676 	debug3("%s: treating %s as a key list", __func__,
677 	    options.revoked_keys_file);
678 	switch (key_in_file(key, options.revoked_keys_file, 0)) {
679 	case 0:
680 		/* key not revoked */
681 		return 0;
682 	case -1:
683 		/* Error opening revoked_keys_file: refuse all keys */
684 		error("Revoked keys file is unreadable: refusing public key "
685 		    "authentication");
686 		return 1;
687 	case 1:
688  revoked:
689 		/* Key revoked */
690 		key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
691 		error("WARNING: authentication attempt with a revoked "
692 		    "%s key %s ", key_type(key), key_fp);
693 		free(key_fp);
694 		return 1;
695 	}
696 	fatal("key_in_file returned junk");
697 }
698 
699 void
700 auth_debug_add(const char *fmt,...)
701 {
702 	char buf[1024];
703 	va_list args;
704 
705 	if (!auth_debug_init)
706 		return;
707 
708 	va_start(args, fmt);
709 	vsnprintf(buf, sizeof(buf), fmt, args);
710 	va_end(args);
711 	buffer_put_cstring(&auth_debug, buf);
712 }
713 
714 void
715 auth_debug_send(void)
716 {
717 	char *msg;
718 
719 	if (!auth_debug_init)
720 		return;
721 	while (buffer_len(&auth_debug)) {
722 		msg = buffer_get_string(&auth_debug, NULL);
723 		packet_send_debug("%s", msg);
724 		free(msg);
725 	}
726 }
727 
728 void
729 auth_debug_reset(void)
730 {
731 	if (auth_debug_init)
732 		buffer_clear(&auth_debug);
733 	else {
734 		buffer_init(&auth_debug);
735 		auth_debug_init = 1;
736 	}
737 }
738 
739 struct passwd *
740 fakepw(void)
741 {
742 	static struct passwd fake;
743 
744 	memset(&fake, 0, sizeof(fake));
745 	fake.pw_name = "NOUSER";
746 	fake.pw_passwd =
747 	    "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
748 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
749 	fake.pw_gecos = "NOUSER";
750 #endif
751 	fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
752 	fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
753 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
754 	fake.pw_class = "";
755 #endif
756 	fake.pw_dir = "/nonexist";
757 	fake.pw_shell = "/nonexist";
758 
759 	return (&fake);
760 }
761