xref: /freebsd/crypto/openssh/auth.c (revision b9c36cc755002809a7d7c7109e3425fdfca036d2)
1 /* $OpenBSD: auth.c,v 1.113 2015/08/21 03:42:19 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 
32 #include <netinet/in.h>
33 
34 #include <errno.h>
35 #include <fcntl.h>
36 #ifdef HAVE_PATHS_H
37 # include <paths.h>
38 #endif
39 #include <pwd.h>
40 #ifdef HAVE_LOGIN_H
41 #include <login.h>
42 #endif
43 #ifdef USE_SHADOW
44 #include <shadow.h>
45 #endif
46 #ifdef HAVE_LIBGEN_H
47 #include <libgen.h>
48 #endif
49 #include <stdarg.h>
50 #include <stdio.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <limits.h>
54 
55 #include "xmalloc.h"
56 #include "match.h"
57 #include "groupaccess.h"
58 #include "log.h"
59 #include "buffer.h"
60 #include "misc.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 "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 "authfile.h"
76 #include "ssherr.h"
77 #include "compat.h"
78 #include "blacklist_client.h"
79 
80 /* import */
81 extern ServerOptions options;
82 extern int use_privsep;
83 extern Buffer loginmsg;
84 extern struct passwd *privsep_pw;
85 
86 /* Debugging messages */
87 Buffer auth_debug;
88 int auth_debug_init;
89 
90 /*
91  * Check if the user is allowed to log in via ssh. If user is listed
92  * in DenyUsers or one of user's groups is listed in DenyGroups, false
93  * will be returned. If AllowUsers isn't empty and user isn't listed
94  * there, or if AllowGroups isn't empty and one of user's groups isn't
95  * listed there, false will be returned.
96  * If the user's shell is not executable, false will be returned.
97  * Otherwise true is returned.
98  */
99 int
100 allowed_user(struct passwd * pw)
101 {
102 	struct stat st;
103 	const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
104 	u_int i;
105 #ifdef USE_SHADOW
106 	struct spwd *spw = NULL;
107 #endif
108 
109 	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
110 	if (!pw || !pw->pw_name)
111 		return 0;
112 
113 #ifdef USE_SHADOW
114 	if (!options.use_pam)
115 		spw = getspnam(pw->pw_name);
116 #ifdef HAS_SHADOW_EXPIRE
117 	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
118 		return 0;
119 #endif /* HAS_SHADOW_EXPIRE */
120 #endif /* USE_SHADOW */
121 
122 	/* grab passwd field for locked account check */
123 	passwd = pw->pw_passwd;
124 #ifdef USE_SHADOW
125 	if (spw != NULL)
126 #ifdef USE_LIBIAF
127 		passwd = get_iaf_password(pw);
128 #else
129 		passwd = spw->sp_pwdp;
130 #endif /* USE_LIBIAF */
131 #endif
132 
133 	/* check for locked account */
134 	if (!options.use_pam && passwd && *passwd) {
135 		int locked = 0;
136 
137 #ifdef LOCKED_PASSWD_STRING
138 		if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
139 			 locked = 1;
140 #endif
141 #ifdef LOCKED_PASSWD_PREFIX
142 		if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
143 		    strlen(LOCKED_PASSWD_PREFIX)) == 0)
144 			 locked = 1;
145 #endif
146 #ifdef LOCKED_PASSWD_SUBSTR
147 		if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
148 			locked = 1;
149 #endif
150 #ifdef USE_LIBIAF
151 		free((void *) passwd);
152 #endif /* USE_LIBIAF */
153 		if (locked) {
154 			logit("User %.100s not allowed because account is locked",
155 			    pw->pw_name);
156 			return 0;
157 		}
158 	}
159 
160 	/*
161 	 * Deny if shell does not exist or is not executable unless we
162 	 * are chrooting.
163 	 */
164 	if (options.chroot_directory == NULL ||
165 	    strcasecmp(options.chroot_directory, "none") == 0) {
166 		char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
167 		    _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
168 
169 		if (stat(shell, &st) != 0) {
170 			logit("User %.100s not allowed because shell %.100s "
171 			    "does not exist", pw->pw_name, shell);
172 			free(shell);
173 			return 0;
174 		}
175 		if (S_ISREG(st.st_mode) == 0 ||
176 		    (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
177 			logit("User %.100s not allowed because shell %.100s "
178 			    "is not executable", pw->pw_name, shell);
179 			free(shell);
180 			return 0;
181 		}
182 		free(shell);
183 	}
184 
185 	if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
186 	    options.num_deny_groups > 0 || options.num_allow_groups > 0) {
187 		hostname = get_canonical_hostname(options.use_dns);
188 		ipaddr = get_remote_ipaddr();
189 	}
190 
191 	/* Return false if user is listed in DenyUsers */
192 	if (options.num_deny_users > 0) {
193 		for (i = 0; i < options.num_deny_users; i++)
194 			if (match_user(pw->pw_name, hostname, ipaddr,
195 			    options.deny_users[i])) {
196 				logit("User %.100s from %.100s not allowed "
197 				    "because listed in DenyUsers",
198 				    pw->pw_name, hostname);
199 				return 0;
200 			}
201 	}
202 	/* Return false if AllowUsers isn't empty and user isn't listed there */
203 	if (options.num_allow_users > 0) {
204 		for (i = 0; i < options.num_allow_users; i++)
205 			if (match_user(pw->pw_name, hostname, ipaddr,
206 			    options.allow_users[i]))
207 				break;
208 		/* i < options.num_allow_users iff we break for loop */
209 		if (i >= options.num_allow_users) {
210 			logit("User %.100s from %.100s not allowed because "
211 			    "not listed in AllowUsers", pw->pw_name, hostname);
212 			return 0;
213 		}
214 	}
215 	if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
216 		/* Get the user's group access list (primary and supplementary) */
217 		if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
218 			logit("User %.100s from %.100s not allowed because "
219 			    "not in any group", pw->pw_name, hostname);
220 			return 0;
221 		}
222 
223 		/* Return false if one of user's groups is listed in DenyGroups */
224 		if (options.num_deny_groups > 0)
225 			if (ga_match(options.deny_groups,
226 			    options.num_deny_groups)) {
227 				ga_free();
228 				logit("User %.100s from %.100s not allowed "
229 				    "because a group is listed in DenyGroups",
230 				    pw->pw_name, hostname);
231 				return 0;
232 			}
233 		/*
234 		 * Return false if AllowGroups isn't empty and one of user's groups
235 		 * isn't listed there
236 		 */
237 		if (options.num_allow_groups > 0)
238 			if (!ga_match(options.allow_groups,
239 			    options.num_allow_groups)) {
240 				ga_free();
241 				logit("User %.100s from %.100s not allowed "
242 				    "because none of user's groups are listed "
243 				    "in AllowGroups", pw->pw_name, hostname);
244 				return 0;
245 			}
246 		ga_free();
247 	}
248 
249 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
250 	if (!sys_auth_allowed_user(pw, &loginmsg))
251 		return 0;
252 #endif
253 
254 	/* We found no reason not to let this user try to log on... */
255 	return 1;
256 }
257 
258 void
259 auth_info(Authctxt *authctxt, const char *fmt, ...)
260 {
261 	va_list ap;
262         int i;
263 
264 	free(authctxt->info);
265 	authctxt->info = NULL;
266 
267 	va_start(ap, fmt);
268 	i = vasprintf(&authctxt->info, fmt, ap);
269 	va_end(ap);
270 
271 	if (i < 0 || authctxt->info == NULL)
272 		fatal("vasprintf failed");
273 }
274 
275 void
276 auth_log(Authctxt *authctxt, int authenticated, int partial,
277     const char *method, const char *submethod)
278 {
279 	void (*authlog) (const char *fmt,...) = verbose;
280 	char *authmsg;
281 
282 	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
283 		return;
284 
285 	/* Raise logging level */
286 	if (authenticated == 1 ||
287 	    !authctxt->valid ||
288 	    authctxt->failures >= options.max_authtries / 2 ||
289 	    strcmp(method, "password") == 0)
290 		authlog = logit;
291 
292 	if (authctxt->postponed)
293 		authmsg = "Postponed";
294 	else if (partial)
295 		authmsg = "Partial";
296 	else {
297 		authmsg = authenticated ? "Accepted" : "Failed";
298 		BLACKLIST_NOTIFY(authenticated ?
299 		    BLACKLIST_AUTH_OK : BLACKLIST_AUTH_FAIL);
300 	}
301 
302 	authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
303 	    authmsg,
304 	    method,
305 	    submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
306 	    authctxt->valid ? "" : "invalid user ",
307 	    authctxt->user,
308 	    get_remote_ipaddr(),
309 	    get_remote_port(),
310 	    compat20 ? "ssh2" : "ssh1",
311 	    authctxt->info != NULL ? ": " : "",
312 	    authctxt->info != NULL ? authctxt->info : "");
313 	free(authctxt->info);
314 	authctxt->info = NULL;
315 
316 #ifdef CUSTOM_FAILED_LOGIN
317 	if (authenticated == 0 && !authctxt->postponed &&
318 	    (strcmp(method, "password") == 0 ||
319 	    strncmp(method, "keyboard-interactive", 20) == 0 ||
320 	    strcmp(method, "challenge-response") == 0))
321 		record_failed_login(authctxt->user,
322 		    get_canonical_hostname(options.use_dns), "ssh");
323 # ifdef WITH_AIXAUTHENTICATE
324 	if (authenticated)
325 		sys_auth_record_login(authctxt->user,
326 		    get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
327 # endif
328 #endif
329 #ifdef SSH_AUDIT_EVENTS
330 	if (authenticated == 0 && !authctxt->postponed)
331 		audit_event(audit_classify_auth(method));
332 #endif
333 }
334 
335 
336 void
337 auth_maxtries_exceeded(Authctxt *authctxt)
338 {
339 	error("maximum authentication attempts exceeded for "
340 	    "%s%.100s from %.200s port %d %s",
341 	    authctxt->valid ? "" : "invalid user ",
342 	    authctxt->user,
343 	    get_remote_ipaddr(),
344 	    get_remote_port(),
345 	    compat20 ? "ssh2" : "ssh1");
346 	packet_disconnect("Too many authentication failures");
347 	/* NOTREACHED */
348 }
349 
350 /*
351  * Check whether root logins are disallowed.
352  */
353 int
354 auth_root_allowed(const char *method)
355 {
356 	switch (options.permit_root_login) {
357 	case PERMIT_YES:
358 		return 1;
359 	case PERMIT_NO_PASSWD:
360 		if (strcmp(method, "publickey") == 0 ||
361 		    strcmp(method, "hostbased") == 0 ||
362 		    strcmp(method, "gssapi-with-mic") == 0)
363 			return 1;
364 		break;
365 	case PERMIT_FORCED_ONLY:
366 		if (forced_command) {
367 			logit("Root login accepted for forced command.");
368 			return 1;
369 		}
370 		break;
371 	}
372 	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
373 	return 0;
374 }
375 
376 
377 /*
378  * Given a template and a passwd structure, build a filename
379  * by substituting % tokenised options. Currently, %% becomes '%',
380  * %h becomes the home directory and %u the username.
381  *
382  * This returns a buffer allocated by xmalloc.
383  */
384 char *
385 expand_authorized_keys(const char *filename, struct passwd *pw)
386 {
387 	char *file, ret[PATH_MAX];
388 	int i;
389 
390 	file = percent_expand(filename, "h", pw->pw_dir,
391 	    "u", pw->pw_name, (char *)NULL);
392 
393 	/*
394 	 * Ensure that filename starts anchored. If not, be backward
395 	 * compatible and prepend the '%h/'
396 	 */
397 	if (*file == '/')
398 		return (file);
399 
400 	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
401 	if (i < 0 || (size_t)i >= sizeof(ret))
402 		fatal("expand_authorized_keys: path too long");
403 	free(file);
404 	return (xstrdup(ret));
405 }
406 
407 char *
408 authorized_principals_file(struct passwd *pw)
409 {
410 	if (options.authorized_principals_file == NULL)
411 		return NULL;
412 	return expand_authorized_keys(options.authorized_principals_file, pw);
413 }
414 
415 /* return ok if key exists in sysfile or userfile */
416 HostStatus
417 check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
418     const char *sysfile, const char *userfile)
419 {
420 	char *user_hostfile;
421 	struct stat st;
422 	HostStatus host_status;
423 	struct hostkeys *hostkeys;
424 	const struct hostkey_entry *found;
425 
426 	hostkeys = init_hostkeys();
427 	load_hostkeys(hostkeys, host, sysfile);
428 	if (userfile != NULL) {
429 		user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
430 		if (options.strict_modes &&
431 		    (stat(user_hostfile, &st) == 0) &&
432 		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
433 		    (st.st_mode & 022) != 0)) {
434 			logit("Authentication refused for %.100s: "
435 			    "bad owner or modes for %.200s",
436 			    pw->pw_name, user_hostfile);
437 			auth_debug_add("Ignored %.200s: bad ownership or modes",
438 			    user_hostfile);
439 		} else {
440 			temporarily_use_uid(pw);
441 			load_hostkeys(hostkeys, host, user_hostfile);
442 			restore_uid();
443 		}
444 		free(user_hostfile);
445 	}
446 	host_status = check_key_in_hostkeys(hostkeys, key, &found);
447 	if (host_status == HOST_REVOKED)
448 		error("WARNING: revoked key for %s attempted authentication",
449 		    found->host);
450 	else if (host_status == HOST_OK)
451 		debug("%s: key for %s found at %s:%ld", __func__,
452 		    found->host, found->file, found->line);
453 	else
454 		debug("%s: key for host %s not found", __func__, host);
455 
456 	free_hostkeys(hostkeys);
457 
458 	return host_status;
459 }
460 
461 /*
462  * Check a given path for security. This is defined as all components
463  * of the path to the file must be owned by either the owner of
464  * of the file or root and no directories must be group or world writable.
465  *
466  * XXX Should any specific check be done for sym links ?
467  *
468  * Takes a file name, its stat information (preferably from fstat() to
469  * avoid races), the uid of the expected owner, their home directory and an
470  * error buffer plus max size as arguments.
471  *
472  * Returns 0 on success and -1 on failure
473  */
474 int
475 auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
476     uid_t uid, char *err, size_t errlen)
477 {
478 	char buf[PATH_MAX], homedir[PATH_MAX];
479 	char *cp;
480 	int comparehome = 0;
481 	struct stat st;
482 
483 	if (realpath(name, buf) == NULL) {
484 		snprintf(err, errlen, "realpath %s failed: %s", name,
485 		    strerror(errno));
486 		return -1;
487 	}
488 	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
489 		comparehome = 1;
490 
491 	if (!S_ISREG(stp->st_mode)) {
492 		snprintf(err, errlen, "%s is not a regular file", buf);
493 		return -1;
494 	}
495 	if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
496 	    (stp->st_mode & 022) != 0) {
497 		snprintf(err, errlen, "bad ownership or modes for file %s",
498 		    buf);
499 		return -1;
500 	}
501 
502 	/* for each component of the canonical path, walking upwards */
503 	for (;;) {
504 		if ((cp = dirname(buf)) == NULL) {
505 			snprintf(err, errlen, "dirname() failed");
506 			return -1;
507 		}
508 		strlcpy(buf, cp, sizeof(buf));
509 
510 		if (stat(buf, &st) < 0 ||
511 		    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
512 		    (st.st_mode & 022) != 0) {
513 			snprintf(err, errlen,
514 			    "bad ownership or modes for directory %s", buf);
515 			return -1;
516 		}
517 
518 		/* If are past the homedir then we can stop */
519 		if (comparehome && strcmp(homedir, buf) == 0)
520 			break;
521 
522 		/*
523 		 * dirname should always complete with a "/" path,
524 		 * but we can be paranoid and check for "." too
525 		 */
526 		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
527 			break;
528 	}
529 	return 0;
530 }
531 
532 /*
533  * Version of secure_path() that accepts an open file descriptor to
534  * avoid races.
535  *
536  * Returns 0 on success and -1 on failure
537  */
538 static int
539 secure_filename(FILE *f, const char *file, struct passwd *pw,
540     char *err, size_t errlen)
541 {
542 	struct stat st;
543 
544 	/* check the open file to avoid races */
545 	if (fstat(fileno(f), &st) < 0) {
546 		snprintf(err, errlen, "cannot stat file %s: %s",
547 		    file, strerror(errno));
548 		return -1;
549 	}
550 	return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
551 }
552 
553 static FILE *
554 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
555     int log_missing, char *file_type)
556 {
557 	char line[1024];
558 	struct stat st;
559 	int fd;
560 	FILE *f;
561 
562 	if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
563 		if (log_missing || errno != ENOENT)
564 			debug("Could not open %s '%s': %s", file_type, file,
565 			   strerror(errno));
566 		return NULL;
567 	}
568 
569 	if (fstat(fd, &st) < 0) {
570 		close(fd);
571 		return NULL;
572 	}
573 	if (!S_ISREG(st.st_mode)) {
574 		logit("User %s %s %s is not a regular file",
575 		    pw->pw_name, file_type, file);
576 		close(fd);
577 		return NULL;
578 	}
579 	unset_nonblock(fd);
580 	if ((f = fdopen(fd, "r")) == NULL) {
581 		close(fd);
582 		return NULL;
583 	}
584 	if (strict_modes &&
585 	    secure_filename(f, file, pw, line, sizeof(line)) != 0) {
586 		fclose(f);
587 		logit("Authentication refused: %s", line);
588 		auth_debug_add("Ignored %s: %s", file_type, line);
589 		return NULL;
590 	}
591 
592 	return f;
593 }
594 
595 
596 FILE *
597 auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
598 {
599 	return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
600 }
601 
602 FILE *
603 auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
604 {
605 	return auth_openfile(file, pw, strict_modes, 0,
606 	    "authorized principals");
607 }
608 
609 struct passwd *
610 getpwnamallow(const char *user)
611 {
612 #ifdef HAVE_LOGIN_CAP
613 	extern login_cap_t *lc;
614 #ifdef BSD_AUTH
615 	auth_session_t *as;
616 #endif
617 #endif
618 	struct passwd *pw;
619 	struct connection_info *ci = get_connection_info(1, options.use_dns);
620 
621 	ci->user = user;
622 	parse_server_match_config(&options, ci);
623 
624 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
625 	aix_setauthdb(user);
626 #endif
627 
628 	pw = getpwnam(user);
629 
630 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
631 	aix_restoreauthdb();
632 #endif
633 #ifdef HAVE_CYGWIN
634 	/*
635 	 * Windows usernames are case-insensitive.  To avoid later problems
636 	 * when trying to match the username, the user is only allowed to
637 	 * login if the username is given in the same case as stored in the
638 	 * user database.
639 	 */
640 	if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
641 		logit("Login name %.100s does not match stored username %.100s",
642 		    user, pw->pw_name);
643 		pw = NULL;
644 	}
645 #endif
646 	if (pw == NULL) {
647 		BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
648 		logit("Invalid user %.100s from %.100s",
649 		    user, get_remote_ipaddr());
650 #ifdef CUSTOM_FAILED_LOGIN
651 		record_failed_login(user,
652 		    get_canonical_hostname(options.use_dns), "ssh");
653 #endif
654 #ifdef SSH_AUDIT_EVENTS
655 		audit_event(SSH_INVALID_USER);
656 #endif /* SSH_AUDIT_EVENTS */
657 		return (NULL);
658 	}
659 	if (!allowed_user(pw))
660 		return (NULL);
661 #ifdef HAVE_LOGIN_CAP
662 	if ((lc = login_getpwclass(pw)) == NULL) {
663 		debug("unable to get login class: %s", user);
664 		return (NULL);
665 	}
666 #ifdef BSD_AUTH
667 	if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
668 	    auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
669 		debug("Approval failure for %s", user);
670 		pw = NULL;
671 	}
672 	if (as != NULL)
673 		auth_close(as);
674 #endif
675 #endif
676 	if (pw != NULL)
677 		return (pwcopy(pw));
678 	return (NULL);
679 }
680 
681 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
682 int
683 auth_key_is_revoked(Key *key)
684 {
685 	char *fp = NULL;
686 	int r;
687 
688 	if (options.revoked_keys_file == NULL)
689 		return 0;
690 	if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
691 	    SSH_FP_DEFAULT)) == NULL) {
692 		r = SSH_ERR_ALLOC_FAIL;
693 		error("%s: fingerprint key: %s", __func__, ssh_err(r));
694 		goto out;
695 	}
696 
697 	r = sshkey_check_revoked(key, options.revoked_keys_file);
698 	switch (r) {
699 	case 0:
700 		break; /* not revoked */
701 	case SSH_ERR_KEY_REVOKED:
702 		error("Authentication key %s %s revoked by file %s",
703 		    sshkey_type(key), fp, options.revoked_keys_file);
704 		goto out;
705 	default:
706 		error("Error checking authentication key %s %s in "
707 		    "revoked keys file %s: %s", sshkey_type(key), fp,
708 		    options.revoked_keys_file, ssh_err(r));
709 		goto out;
710 	}
711 
712 	/* Success */
713 	r = 0;
714 
715  out:
716 	free(fp);
717 	return r == 0 ? 0 : 1;
718 }
719 
720 void
721 auth_debug_add(const char *fmt,...)
722 {
723 	char buf[1024];
724 	va_list args;
725 
726 	if (!auth_debug_init)
727 		return;
728 
729 	va_start(args, fmt);
730 	vsnprintf(buf, sizeof(buf), fmt, args);
731 	va_end(args);
732 	buffer_put_cstring(&auth_debug, buf);
733 }
734 
735 void
736 auth_debug_send(void)
737 {
738 	char *msg;
739 
740 	if (!auth_debug_init)
741 		return;
742 	while (buffer_len(&auth_debug)) {
743 		msg = buffer_get_string(&auth_debug, NULL);
744 		packet_send_debug("%s", msg);
745 		free(msg);
746 	}
747 }
748 
749 void
750 auth_debug_reset(void)
751 {
752 	if (auth_debug_init)
753 		buffer_clear(&auth_debug);
754 	else {
755 		buffer_init(&auth_debug);
756 		auth_debug_init = 1;
757 	}
758 }
759 
760 struct passwd *
761 fakepw(void)
762 {
763 	static struct passwd fake;
764 
765 	memset(&fake, 0, sizeof(fake));
766 	fake.pw_name = "NOUSER";
767 	fake.pw_passwd =
768 	    "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
769 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
770 	fake.pw_gecos = "NOUSER";
771 #endif
772 	fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
773 	fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
774 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
775 	fake.pw_class = "";
776 #endif
777 	fake.pw_dir = "/nonexist";
778 	fake.pw_shell = "/nonexist";
779 
780 	return (&fake);
781 }
782