xref: /freebsd/crypto/openssh/auth.c (revision 2830819497fb2deae3dd71574592ace55f2fbdba)
1 /* $OpenBSD: auth.c,v 1.103 2013/05/19 02:42:42 djm Exp $ */
2 /*
3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include "includes.h"
27 __RCSID("$FreeBSD$");
28 
29 #include <sys/types.h>
30 #include <sys/stat.h>
31 #include <sys/param.h>
32 
33 #include <netinet/in.h>
34 
35 #include <errno.h>
36 #include <fcntl.h>
37 #ifdef HAVE_PATHS_H
38 # include <paths.h>
39 #endif
40 #include <pwd.h>
41 #ifdef HAVE_LOGIN_H
42 #include <login.h>
43 #endif
44 #ifdef USE_SHADOW
45 #include <shadow.h>
46 #endif
47 #ifdef HAVE_LIBGEN_H
48 #include <libgen.h>
49 #endif
50 #include <stdarg.h>
51 #include <stdio.h>
52 #include <string.h>
53 #include <unistd.h>
54 
55 #include "xmalloc.h"
56 #include "match.h"
57 #include "groupaccess.h"
58 #include "log.h"
59 #include "buffer.h"
60 #include "servconf.h"
61 #include "key.h"
62 #include "hostfile.h"
63 #include "auth.h"
64 #include "auth-options.h"
65 #include "canohost.h"
66 #include "uidswap.h"
67 #include "misc.h"
68 #include "packet.h"
69 #include "loginrec.h"
70 #ifdef GSSAPI
71 #include "ssh-gss.h"
72 #endif
73 #include "authfile.h"
74 #include "monitor_wrap.h"
75 #include "krl.h"
76 #include "compat.h"
77 
78 /* import */
79 extern ServerOptions options;
80 extern int use_privsep;
81 extern Buffer loginmsg;
82 extern struct passwd *privsep_pw;
83 
84 /* Debugging messages */
85 Buffer auth_debug;
86 int auth_debug_init;
87 
88 /*
89  * Check if the user is allowed to log in via ssh. If user is listed
90  * in DenyUsers or one of user's groups is listed in DenyGroups, false
91  * will be returned. If AllowUsers isn't empty and user isn't listed
92  * there, or if AllowGroups isn't empty and one of user's groups isn't
93  * listed there, false will be returned.
94  * If the user's shell is not executable, false will be returned.
95  * Otherwise true is returned.
96  */
97 int
98 allowed_user(struct passwd * pw)
99 {
100 	struct stat st;
101 	const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
102 	u_int i;
103 #ifdef USE_SHADOW
104 	struct spwd *spw = NULL;
105 #endif
106 
107 	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
108 	if (!pw || !pw->pw_name)
109 		return 0;
110 
111 #ifdef USE_SHADOW
112 	if (!options.use_pam)
113 		spw = getspnam(pw->pw_name);
114 #ifdef HAS_SHADOW_EXPIRE
115 	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
116 		return 0;
117 #endif /* HAS_SHADOW_EXPIRE */
118 #endif /* USE_SHADOW */
119 
120 	/* grab passwd field for locked account check */
121 	passwd = pw->pw_passwd;
122 #ifdef USE_SHADOW
123 	if (spw != NULL)
124 #ifdef USE_LIBIAF
125 		passwd = get_iaf_password(pw);
126 #else
127 		passwd = spw->sp_pwdp;
128 #endif /* USE_LIBIAF */
129 #endif
130 
131 	/* check for locked account */
132 	if (!options.use_pam && passwd && *passwd) {
133 		int locked = 0;
134 
135 #ifdef LOCKED_PASSWD_STRING
136 		if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
137 			 locked = 1;
138 #endif
139 #ifdef LOCKED_PASSWD_PREFIX
140 		if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
141 		    strlen(LOCKED_PASSWD_PREFIX)) == 0)
142 			 locked = 1;
143 #endif
144 #ifdef LOCKED_PASSWD_SUBSTR
145 		if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
146 			locked = 1;
147 #endif
148 #ifdef USE_LIBIAF
149 		free((void *) passwd);
150 #endif /* USE_LIBIAF */
151 		if (locked) {
152 			logit("User %.100s not allowed because account is locked",
153 			    pw->pw_name);
154 			return 0;
155 		}
156 	}
157 
158 	/*
159 	 * Deny if shell does not exist or is not executable unless we
160 	 * are chrooting.
161 	 */
162 	if (options.chroot_directory == NULL ||
163 	    strcasecmp(options.chroot_directory, "none") == 0) {
164 		char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
165 		    _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
166 
167 		if (stat(shell, &st) != 0) {
168 			logit("User %.100s not allowed because shell %.100s "
169 			    "does not exist", pw->pw_name, shell);
170 			free(shell);
171 			return 0;
172 		}
173 		if (S_ISREG(st.st_mode) == 0 ||
174 		    (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
175 			logit("User %.100s not allowed because shell %.100s "
176 			    "is not executable", pw->pw_name, shell);
177 			free(shell);
178 			return 0;
179 		}
180 		free(shell);
181 	}
182 
183 	if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
184 	    options.num_deny_groups > 0 || options.num_allow_groups > 0) {
185 		hostname = get_canonical_hostname(options.use_dns);
186 		ipaddr = get_remote_ipaddr();
187 	}
188 
189 	/* Return false if user is listed in DenyUsers */
190 	if (options.num_deny_users > 0) {
191 		for (i = 0; i < options.num_deny_users; i++)
192 			if (match_user(pw->pw_name, hostname, ipaddr,
193 			    options.deny_users[i])) {
194 				logit("User %.100s from %.100s not allowed "
195 				    "because listed in DenyUsers",
196 				    pw->pw_name, hostname);
197 				return 0;
198 			}
199 	}
200 	/* Return false if AllowUsers isn't empty and user isn't listed there */
201 	if (options.num_allow_users > 0) {
202 		for (i = 0; i < options.num_allow_users; i++)
203 			if (match_user(pw->pw_name, hostname, ipaddr,
204 			    options.allow_users[i]))
205 				break;
206 		/* i < options.num_allow_users iff we break for loop */
207 		if (i >= options.num_allow_users) {
208 			logit("User %.100s from %.100s not allowed because "
209 			    "not listed in AllowUsers", pw->pw_name, hostname);
210 			return 0;
211 		}
212 	}
213 	if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
214 		/* Get the user's group access list (primary and supplementary) */
215 		if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
216 			logit("User %.100s from %.100s not allowed because "
217 			    "not in any group", pw->pw_name, hostname);
218 			return 0;
219 		}
220 
221 		/* Return false if one of user's groups is listed in DenyGroups */
222 		if (options.num_deny_groups > 0)
223 			if (ga_match(options.deny_groups,
224 			    options.num_deny_groups)) {
225 				ga_free();
226 				logit("User %.100s from %.100s not allowed "
227 				    "because a group is listed in DenyGroups",
228 				    pw->pw_name, hostname);
229 				return 0;
230 			}
231 		/*
232 		 * Return false if AllowGroups isn't empty and one of user's groups
233 		 * isn't listed there
234 		 */
235 		if (options.num_allow_groups > 0)
236 			if (!ga_match(options.allow_groups,
237 			    options.num_allow_groups)) {
238 				ga_free();
239 				logit("User %.100s from %.100s not allowed "
240 				    "because none of user's groups are listed "
241 				    "in AllowGroups", pw->pw_name, hostname);
242 				return 0;
243 			}
244 		ga_free();
245 	}
246 
247 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
248 	if (!sys_auth_allowed_user(pw, &loginmsg))
249 		return 0;
250 #endif
251 
252 	/* We found no reason not to let this user try to log on... */
253 	return 1;
254 }
255 
256 void
257 auth_info(Authctxt *authctxt, const char *fmt, ...)
258 {
259 	va_list ap;
260         int i;
261 
262 	free(authctxt->info);
263 	authctxt->info = NULL;
264 
265 	va_start(ap, fmt);
266 	i = vasprintf(&authctxt->info, fmt, ap);
267 	va_end(ap);
268 
269 	if (i < 0 || authctxt->info == NULL)
270 		fatal("vasprintf failed");
271 }
272 
273 void
274 auth_log(Authctxt *authctxt, int authenticated, int partial,
275     const char *method, const char *submethod)
276 {
277 	void (*authlog) (const char *fmt,...) = verbose;
278 	char *authmsg;
279 
280 	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
281 		return;
282 
283 	/* Raise logging level */
284 	if (authenticated == 1 ||
285 	    !authctxt->valid ||
286 	    authctxt->failures >= options.max_authtries / 2 ||
287 	    strcmp(method, "password") == 0)
288 		authlog = logit;
289 
290 	if (authctxt->postponed)
291 		authmsg = "Postponed";
292 	else if (partial)
293 		authmsg = "Partial";
294 	else
295 		authmsg = authenticated ? "Accepted" : "Failed";
296 
297 	authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
298 	    authmsg,
299 	    method,
300 	    submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
301 	    authctxt->valid ? "" : "invalid user ",
302 	    authctxt->user,
303 	    get_remote_ipaddr(),
304 	    get_remote_port(),
305 	    compat20 ? "ssh2" : "ssh1",
306 	    authctxt->info != NULL ? ": " : "",
307 	    authctxt->info != NULL ? authctxt->info : "");
308 	free(authctxt->info);
309 	authctxt->info = NULL;
310 
311 #ifdef CUSTOM_FAILED_LOGIN
312 	if (authenticated == 0 && !authctxt->postponed &&
313 	    (strcmp(method, "password") == 0 ||
314 	    strncmp(method, "keyboard-interactive", 20) == 0 ||
315 	    strcmp(method, "challenge-response") == 0))
316 		record_failed_login(authctxt->user,
317 		    get_canonical_hostname(options.use_dns), "ssh");
318 # ifdef WITH_AIXAUTHENTICATE
319 	if (authenticated)
320 		sys_auth_record_login(authctxt->user,
321 		    get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
322 # endif
323 #endif
324 #ifdef SSH_AUDIT_EVENTS
325 	if (authenticated == 0 && !authctxt->postponed)
326 		audit_event(audit_classify_auth(method));
327 #endif
328 }
329 
330 /*
331  * Check whether root logins are disallowed.
332  */
333 int
334 auth_root_allowed(const char *method)
335 {
336 	switch (options.permit_root_login) {
337 	case PERMIT_YES:
338 		return 1;
339 	case PERMIT_NO_PASSWD:
340 		if (strcmp(method, "password") != 0)
341 			return 1;
342 		break;
343 	case PERMIT_FORCED_ONLY:
344 		if (forced_command) {
345 			logit("Root login accepted for forced command.");
346 			return 1;
347 		}
348 		break;
349 	}
350 	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
351 	return 0;
352 }
353 
354 
355 /*
356  * Given a template and a passwd structure, build a filename
357  * by substituting % tokenised options. Currently, %% becomes '%',
358  * %h becomes the home directory and %u the username.
359  *
360  * This returns a buffer allocated by xmalloc.
361  */
362 char *
363 expand_authorized_keys(const char *filename, struct passwd *pw)
364 {
365 	char *file, ret[MAXPATHLEN];
366 	int i;
367 
368 	file = percent_expand(filename, "h", pw->pw_dir,
369 	    "u", pw->pw_name, (char *)NULL);
370 
371 	/*
372 	 * Ensure that filename starts anchored. If not, be backward
373 	 * compatible and prepend the '%h/'
374 	 */
375 	if (*file == '/')
376 		return (file);
377 
378 	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
379 	if (i < 0 || (size_t)i >= sizeof(ret))
380 		fatal("expand_authorized_keys: path too long");
381 	free(file);
382 	return (xstrdup(ret));
383 }
384 
385 char *
386 authorized_principals_file(struct passwd *pw)
387 {
388 	if (options.authorized_principals_file == NULL ||
389 	    strcasecmp(options.authorized_principals_file, "none") == 0)
390 		return NULL;
391 	return expand_authorized_keys(options.authorized_principals_file, pw);
392 }
393 
394 /* return ok if key exists in sysfile or userfile */
395 HostStatus
396 check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
397     const char *sysfile, const char *userfile)
398 {
399 	char *user_hostfile;
400 	struct stat st;
401 	HostStatus host_status;
402 	struct hostkeys *hostkeys;
403 	const struct hostkey_entry *found;
404 
405 	hostkeys = init_hostkeys();
406 	load_hostkeys(hostkeys, host, sysfile);
407 	if (userfile != NULL) {
408 		user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
409 		if (options.strict_modes &&
410 		    (stat(user_hostfile, &st) == 0) &&
411 		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
412 		    (st.st_mode & 022) != 0)) {
413 			logit("Authentication refused for %.100s: "
414 			    "bad owner or modes for %.200s",
415 			    pw->pw_name, user_hostfile);
416 			auth_debug_add("Ignored %.200s: bad ownership or modes",
417 			    user_hostfile);
418 		} else {
419 			temporarily_use_uid(pw);
420 			load_hostkeys(hostkeys, host, user_hostfile);
421 			restore_uid();
422 		}
423 		free(user_hostfile);
424 	}
425 	host_status = check_key_in_hostkeys(hostkeys, key, &found);
426 	if (host_status == HOST_REVOKED)
427 		error("WARNING: revoked key for %s attempted authentication",
428 		    found->host);
429 	else if (host_status == HOST_OK)
430 		debug("%s: key for %s found at %s:%ld", __func__,
431 		    found->host, found->file, found->line);
432 	else
433 		debug("%s: key for host %s not found", __func__, host);
434 
435 	free_hostkeys(hostkeys);
436 
437 	return host_status;
438 }
439 
440 /*
441  * Check a given path for security. This is defined as all components
442  * of the path to the file must be owned by either the owner of
443  * of the file or root and no directories must be group or world writable.
444  *
445  * XXX Should any specific check be done for sym links ?
446  *
447  * Takes a file name, its stat information (preferably from fstat() to
448  * avoid races), the uid of the expected owner, their home directory and an
449  * error buffer plus max size as arguments.
450  *
451  * Returns 0 on success and -1 on failure
452  */
453 int
454 auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
455     uid_t uid, char *err, size_t errlen)
456 {
457 	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
458 	char *cp;
459 	int comparehome = 0;
460 	struct stat st;
461 
462 	if (realpath(name, buf) == NULL) {
463 		snprintf(err, errlen, "realpath %s failed: %s", name,
464 		    strerror(errno));
465 		return -1;
466 	}
467 	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
468 		comparehome = 1;
469 
470 	if (!S_ISREG(stp->st_mode)) {
471 		snprintf(err, errlen, "%s is not a regular file", buf);
472 		return -1;
473 	}
474 	if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
475 	    (stp->st_mode & 022) != 0) {
476 		snprintf(err, errlen, "bad ownership or modes for file %s",
477 		    buf);
478 		return -1;
479 	}
480 
481 	/* for each component of the canonical path, walking upwards */
482 	for (;;) {
483 		if ((cp = dirname(buf)) == NULL) {
484 			snprintf(err, errlen, "dirname() failed");
485 			return -1;
486 		}
487 		strlcpy(buf, cp, sizeof(buf));
488 
489 		if (stat(buf, &st) < 0 ||
490 		    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
491 		    (st.st_mode & 022) != 0) {
492 			snprintf(err, errlen,
493 			    "bad ownership or modes for directory %s", buf);
494 			return -1;
495 		}
496 
497 		/* If are past the homedir then we can stop */
498 		if (comparehome && strcmp(homedir, buf) == 0)
499 			break;
500 
501 		/*
502 		 * dirname should always complete with a "/" path,
503 		 * but we can be paranoid and check for "." too
504 		 */
505 		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
506 			break;
507 	}
508 	return 0;
509 }
510 
511 /*
512  * Version of secure_path() that accepts an open file descriptor to
513  * avoid races.
514  *
515  * Returns 0 on success and -1 on failure
516  */
517 static int
518 secure_filename(FILE *f, const char *file, struct passwd *pw,
519     char *err, size_t errlen)
520 {
521 	struct stat st;
522 
523 	/* check the open file to avoid races */
524 	if (fstat(fileno(f), &st) < 0) {
525 		snprintf(err, errlen, "cannot stat file %s: %s",
526 		    file, strerror(errno));
527 		return -1;
528 	}
529 	return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
530 }
531 
532 static FILE *
533 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
534     int log_missing, char *file_type)
535 {
536 	char line[1024];
537 	struct stat st;
538 	int fd;
539 	FILE *f;
540 
541 	if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
542 		if (log_missing || errno != ENOENT)
543 			debug("Could not open %s '%s': %s", file_type, file,
544 			   strerror(errno));
545 		return NULL;
546 	}
547 
548 	if (fstat(fd, &st) < 0) {
549 		close(fd);
550 		return NULL;
551 	}
552 	if (!S_ISREG(st.st_mode)) {
553 		logit("User %s %s %s is not a regular file",
554 		    pw->pw_name, file_type, file);
555 		close(fd);
556 		return NULL;
557 	}
558 	unset_nonblock(fd);
559 	if ((f = fdopen(fd, "r")) == NULL) {
560 		close(fd);
561 		return NULL;
562 	}
563 	if (strict_modes &&
564 	    secure_filename(f, file, pw, line, sizeof(line)) != 0) {
565 		fclose(f);
566 		logit("Authentication refused: %s", line);
567 		auth_debug_add("Ignored %s: %s", file_type, line);
568 		return NULL;
569 	}
570 
571 	return f;
572 }
573 
574 
575 FILE *
576 auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
577 {
578 	return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
579 }
580 
581 FILE *
582 auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
583 {
584 	return auth_openfile(file, pw, strict_modes, 0,
585 	    "authorized principals");
586 }
587 
588 struct passwd *
589 getpwnamallow(const char *user)
590 {
591 #ifdef HAVE_LOGIN_CAP
592 	extern login_cap_t *lc;
593 #ifdef BSD_AUTH
594 	auth_session_t *as;
595 #endif
596 #endif
597 	struct passwd *pw;
598 	struct connection_info *ci = get_connection_info(1, options.use_dns);
599 
600 	ci->user = user;
601 	parse_server_match_config(&options, ci);
602 
603 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
604 	aix_setauthdb(user);
605 #endif
606 
607 	pw = getpwnam(user);
608 
609 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
610 	aix_restoreauthdb();
611 #endif
612 #ifdef HAVE_CYGWIN
613 	/*
614 	 * Windows usernames are case-insensitive.  To avoid later problems
615 	 * when trying to match the username, the user is only allowed to
616 	 * login if the username is given in the same case as stored in the
617 	 * user database.
618 	 */
619 	if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
620 		logit("Login name %.100s does not match stored username %.100s",
621 		    user, pw->pw_name);
622 		pw = NULL;
623 	}
624 #endif
625 	if (pw == NULL) {
626 		logit("Invalid user %.100s from %.100s",
627 		    user, get_remote_ipaddr());
628 #ifdef CUSTOM_FAILED_LOGIN
629 		record_failed_login(user,
630 		    get_canonical_hostname(options.use_dns), "ssh");
631 #endif
632 #ifdef SSH_AUDIT_EVENTS
633 		audit_event(SSH_INVALID_USER);
634 #endif /* SSH_AUDIT_EVENTS */
635 		return (NULL);
636 	}
637 	if (!allowed_user(pw))
638 		return (NULL);
639 #ifdef HAVE_LOGIN_CAP
640 	if ((lc = login_getpwclass(pw)) == NULL) {
641 		debug("unable to get login class: %s", user);
642 		return (NULL);
643 	}
644 #ifdef BSD_AUTH
645 	if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
646 	    auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
647 		debug("Approval failure for %s", user);
648 		pw = NULL;
649 	}
650 	if (as != NULL)
651 		auth_close(as);
652 #endif
653 #endif
654 	if (pw != NULL)
655 		return (pwcopy(pw));
656 	return (NULL);
657 }
658 
659 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
660 int
661 auth_key_is_revoked(Key *key)
662 {
663 	char *key_fp;
664 
665 	if (options.revoked_keys_file == NULL)
666 		return 0;
667 	switch (ssh_krl_file_contains_key(options.revoked_keys_file, key)) {
668 	case 0:
669 		return 0;	/* Not revoked */
670 	case -2:
671 		break;		/* Not a KRL */
672 	default:
673 		goto revoked;
674 	}
675 	debug3("%s: treating %s as a key list", __func__,
676 	    options.revoked_keys_file);
677 	switch (key_in_file(key, options.revoked_keys_file, 0)) {
678 	case 0:
679 		/* key not revoked */
680 		return 0;
681 	case -1:
682 		/* Error opening revoked_keys_file: refuse all keys */
683 		error("Revoked keys file is unreadable: refusing public key "
684 		    "authentication");
685 		return 1;
686 	case 1:
687  revoked:
688 		/* Key revoked */
689 		key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
690 		error("WARNING: authentication attempt with a revoked "
691 		    "%s key %s ", key_type(key), key_fp);
692 		free(key_fp);
693 		return 1;
694 	}
695 	fatal("key_in_file returned junk");
696 }
697 
698 void
699 auth_debug_add(const char *fmt,...)
700 {
701 	char buf[1024];
702 	va_list args;
703 
704 	if (!auth_debug_init)
705 		return;
706 
707 	va_start(args, fmt);
708 	vsnprintf(buf, sizeof(buf), fmt, args);
709 	va_end(args);
710 	buffer_put_cstring(&auth_debug, buf);
711 }
712 
713 void
714 auth_debug_send(void)
715 {
716 	char *msg;
717 
718 	if (!auth_debug_init)
719 		return;
720 	while (buffer_len(&auth_debug)) {
721 		msg = buffer_get_string(&auth_debug, NULL);
722 		packet_send_debug("%s", msg);
723 		free(msg);
724 	}
725 }
726 
727 void
728 auth_debug_reset(void)
729 {
730 	if (auth_debug_init)
731 		buffer_clear(&auth_debug);
732 	else {
733 		buffer_init(&auth_debug);
734 		auth_debug_init = 1;
735 	}
736 }
737 
738 struct passwd *
739 fakepw(void)
740 {
741 	static struct passwd fake;
742 
743 	memset(&fake, 0, sizeof(fake));
744 	fake.pw_name = "NOUSER";
745 	fake.pw_passwd =
746 	    "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
747 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
748 	fake.pw_gecos = "NOUSER";
749 #endif
750 	fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
751 	fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
752 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
753 	fake.pw_class = "";
754 #endif
755 	fake.pw_dir = "/nonexist";
756 	fake.pw_shell = "/nonexist";
757 
758 	return (&fake);
759 }
760