blob: a449061741afc1c47e0fb274f307ca23668d7e5a [file] [log] [blame]
djm@openbsd.orgdbee4112017-09-12 06:32:07 +00001/* $OpenBSD: auth.c,v 1.124 2017/09/12 06:32:07 djm Exp $ */
Damien Miller116e6df2002-05-22 15:06:28 +10002/*
Ben Lindstrom92a2e382001-03-05 06:59:27 +00003 * Copyright (c) 2000 Markus Friedl. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +11004 *
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.
Damien Millerb38eff82000-04-01 11:09:21 +100024 */
25
26#include "includes.h"
Damien Millerf17883e2006-03-15 11:45:54 +110027
28#include <sys/types.h>
29#include <sys/stat.h>
djm@openbsd.org95767262016-03-07 19:02:43 +000030#include <sys/socket.h>
Damien Millerb38eff82000-04-01 11:09:21 +100031
Damien Miller36cbe412006-08-05 12:54:24 +100032#include <netinet/in.h>
33
Darren Tucker39972492006-07-12 22:22:46 +100034#include <errno.h>
Darren Tucker33c787f2008-07-02 22:37:30 +100035#include <fcntl.h>
Damien Miller03e20032006-03-15 11:16:59 +110036#ifdef HAVE_PATHS_H
Damien Millera9263d02006-03-15 11:18:26 +110037# include <paths.h>
Damien Miller03e20032006-03-15 11:16:59 +110038#endif
Damien Miller9f2abc42006-07-10 20:53:08 +100039#include <pwd.h>
Damien Millerd2c208a2000-05-17 22:00:02 +100040#ifdef HAVE_LOGIN_H
41#include <login.h>
42#endif
Darren Tucker15ee7482004-02-22 09:43:15 +110043#ifdef USE_SHADOW
Damien Miller1f335fb2000-06-26 11:31:33 +100044#include <shadow.h>
Darren Tucker15ee7482004-02-22 09:43:15 +110045#endif
Darren Tucker5d196262006-07-12 22:15:16 +100046#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100047#include <stdio.h>
Damien Millere3476ed2006-07-24 14:13:33 +100048#include <string.h>
Damien Miller7acf5502008-07-09 20:54:37 +100049#include <unistd.h>
deraadt@openbsd.org087266e2015-01-20 23:14:00 +000050#include <limits.h>
djm@openbsd.org95767262016-03-07 19:02:43 +000051#include <netdb.h>
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000052
Ben Lindstrom226cfa02001-01-22 05:34:40 +000053#include "xmalloc.h"
54#include "match.h"
55#include "groupaccess.h"
56#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100057#include "buffer.h"
Damien Miller7acefbb2014-07-18 14:11:24 +100058#include "misc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000059#include "servconf.h"
Damien Millerd7834352006-08-05 12:39:39 +100060#include "key.h"
61#include "hostfile.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100062#include "auth.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000063#include "auth-options.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000064#include "canohost.h"
Ben Lindstrom83647ce2001-06-25 04:30:16 +000065#include "uidswap.h"
Ben Lindstroma574cda2002-05-15 16:16:14 +000066#include "packet.h"
Darren Tucker42d9dc72005-02-02 17:10:11 +110067#include "loginrec.h"
Damien Millerd7834352006-08-05 12:39:39 +100068#ifdef GSSAPI
69#include "ssh-gss.h"
70#endif
Damien Miller1aed65e2010-03-04 21:53:35 +110071#include "authfile.h"
Darren Tucker269a1ea2005-02-03 00:20:53 +110072#include "monitor_wrap.h"
djm@openbsd.org5e39a492014-12-04 02:24:32 +000073#include "authfile.h"
74#include "ssherr.h"
Darren Tucker0acca372013-06-02 07:41:51 +100075#include "compat.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100076
Damien Millerb38eff82000-04-01 11:09:21 +100077/* import */
78extern ServerOptions options;
Damien Miller7a8f5b32006-03-31 23:14:23 +110079extern int use_privsep;
Darren Tuckerb9aa0a02003-07-08 22:59:59 +100080extern Buffer loginmsg;
Damien Miller6433df02006-09-07 10:36:43 +100081extern struct passwd *privsep_pw;
Damien Millerb38eff82000-04-01 11:09:21 +100082
Ben Lindstroma574cda2002-05-15 16:16:14 +000083/* Debugging messages */
84Buffer auth_debug;
85int auth_debug_init;
86
Damien Millerb38eff82000-04-01 11:09:21 +100087/*
Kevin Steves7b61cfa2001-01-14 19:11:00 +000088 * Check if the user is allowed to log in via ssh. If user is listed
89 * in DenyUsers or one of user's groups is listed in DenyGroups, false
90 * will be returned. If AllowUsers isn't empty and user isn't listed
91 * there, or if AllowGroups isn't empty and one of user's groups isn't
92 * listed there, false will be returned.
Damien Millerb38eff82000-04-01 11:09:21 +100093 * If the user's shell is not executable, false will be returned.
Damien Miller4af51302000-04-16 11:18:38 +100094 * Otherwise true is returned.
Damien Millerb38eff82000-04-01 11:09:21 +100095 */
Damien Millereba71ba2000-04-29 23:57:08 +100096int
Damien Millerb38eff82000-04-01 11:09:21 +100097allowed_user(struct passwd * pw)
98{
djm@openbsd.org95767262016-03-07 19:02:43 +000099 struct ssh *ssh = active_state; /* XXX */
Damien Millerb38eff82000-04-01 11:09:21 +1000100 struct stat st;
Darren Tucker43a0dc62003-08-26 14:22:12 +1000101 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
Damien Millereccb9de2005-06-17 12:59:34 +1000102 u_int i;
djm@openbsd.org010359b2016-11-06 05:46:37 +0000103 int r;
Darren Tucker15ee7482004-02-22 09:43:15 +1100104#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000105 struct spwd *spw = NULL;
Tim Rice458c6bf2003-01-08 20:04:27 -0800106#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000107
108 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000109 if (!pw || !pw->pw_name)
Damien Millerb38eff82000-04-01 11:09:21 +1000110 return 0;
111
Darren Tucker15ee7482004-02-22 09:43:15 +1100112#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000113 if (!options.use_pam)
114 spw = getspnam(pw->pw_name);
115#ifdef HAS_SHADOW_EXPIRE
Darren Tucker15ee7482004-02-22 09:43:15 +1100116 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
117 return 0;
Darren Tuckere41bba52003-08-25 11:51:19 +1000118#endif /* HAS_SHADOW_EXPIRE */
Darren Tucker15ee7482004-02-22 09:43:15 +1100119#endif /* USE_SHADOW */
Darren Tuckere41bba52003-08-25 11:51:19 +1000120
Damien Millera8e06ce2003-11-21 23:48:55 +1100121 /* grab passwd field for locked account check */
Damien Miller22989f12008-07-05 08:59:43 +1000122 passwd = pw->pw_passwd;
Darren Tucker15ee7482004-02-22 09:43:15 +1100123#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000124 if (spw != NULL)
Tim Rice99203ec2007-03-26 09:35:28 -0700125#ifdef USE_LIBIAF
Tim Rice2291c002005-08-26 13:15:19 -0700126 passwd = get_iaf_password(pw);
127#else
Darren Tuckere41bba52003-08-25 11:51:19 +1000128 passwd = spw->sp_pwdp;
Tim Rice99203ec2007-03-26 09:35:28 -0700129#endif /* USE_LIBIAF */
Damien Miller06817f92003-01-07 23:55:59 +1100130#endif
131
Damien Millera8e06ce2003-11-21 23:48:55 +1100132 /* check for locked account */
Darren Tucker43a0dc62003-08-26 14:22:12 +1000133 if (!options.use_pam && passwd && *passwd) {
Darren Tuckere41bba52003-08-25 11:51:19 +1000134 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
Tim Rice99203ec2007-03-26 09:35:28 -0700149#ifdef USE_LIBIAF
Tim Ricead7d5472010-08-12 10:33:01 -0700150 free((void *) passwd);
Tim Rice99203ec2007-03-26 09:35:28 -0700151#endif /* USE_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000152 if (locked) {
153 logit("User %.100s not allowed because account is locked",
154 pw->pw_name);
155 return 0;
156 }
157 }
158
Damien Milleref7df542000-05-19 00:03:23 +1000159 /*
Damien Miller47cf16b2010-02-12 09:25:29 +1100160 * Deny if shell does not exist or is not executable unless we
161 * are chrooting.
Damien Milleref7df542000-05-19 00:03:23 +1000162 */
Damien Miller47cf16b2010-02-12 09:25:29 +1100163 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 */
Darren Tucker94881d82010-01-15 11:44:46 +1100167
Damien Miller47cf16b2010-02-12 09:25:29 +1100168 if (stat(shell, &st) != 0) {
169 logit("User %.100s not allowed because shell %.100s "
170 "does not exist", pw->pw_name, shell);
Darren Tuckera627d422013-06-02 07:31:17 +1000171 free(shell);
Damien Miller47cf16b2010-02-12 09:25:29 +1100172 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);
Darren Tuckera627d422013-06-02 07:31:17 +1000178 free(shell);
Damien Miller47cf16b2010-02-12 09:25:29 +1100179 return 0;
180 }
Darren Tuckera627d422013-06-02 07:31:17 +1000181 free(shell);
Darren Tucker94881d82010-01-15 11:44:46 +1100182 }
Damien Milleref7df542000-05-19 00:03:23 +1000183
Darren Tuckera8f553d2005-03-14 23:17:27 +1100184 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
185 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
djm@openbsd.org95767262016-03-07 19:02:43 +0000186 hostname = auth_get_canonical_hostname(ssh, options.use_dns);
187 ipaddr = ssh_remote_ipaddr(ssh);
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000188 }
189
Damien Millerb38eff82000-04-01 11:09:21 +1000190 /* Return false if user is listed in DenyUsers */
191 if (options.num_deny_users > 0) {
dtucker@openbsd.orgfe06b682016-12-15 21:29:05 +0000192 for (i = 0; i < options.num_deny_users; i++) {
djm@openbsd.org010359b2016-11-06 05:46:37 +0000193 r = match_user(pw->pw_name, hostname, ipaddr,
194 options.deny_users[i]);
195 if (r < 0) {
196 fatal("Invalid DenyUsers pattern \"%.100s\"",
197 options.deny_users[i]);
djm@openbsd.org1a6f9d22016-11-08 22:04:34 +0000198 } else if (r != 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100199 logit("User %.100s from %.100s not allowed "
200 "because listed in DenyUsers",
201 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000202 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000203 }
dtucker@openbsd.orgfe06b682016-12-15 21:29:05 +0000204 }
Damien Millerb38eff82000-04-01 11:09:21 +1000205 }
206 /* Return false if AllowUsers isn't empty and user isn't listed there */
207 if (options.num_allow_users > 0) {
djm@openbsd.org010359b2016-11-06 05:46:37 +0000208 for (i = 0; i < options.num_allow_users; i++) {
209 r = match_user(pw->pw_name, hostname, ipaddr,
210 options.allow_users[i]);
211 if (r < 0) {
212 fatal("Invalid AllowUsers pattern \"%.100s\"",
213 options.allow_users[i]);
214 } else if (r == 1)
Damien Millerb38eff82000-04-01 11:09:21 +1000215 break;
djm@openbsd.org010359b2016-11-06 05:46:37 +0000216 }
Damien Millerb38eff82000-04-01 11:09:21 +1000217 /* i < options.num_allow_users iff we break for loop */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000218 if (i >= options.num_allow_users) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100219 logit("User %.100s from %.100s not allowed because "
220 "not listed in AllowUsers", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000221 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000222 }
Damien Millerb38eff82000-04-01 11:09:21 +1000223 }
Damien Millerb38eff82000-04-01 11:09:21 +1000224 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000225 /* Get the user's group access list (primary and supplementary) */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000226 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100227 logit("User %.100s from %.100s not allowed because "
228 "not in any group", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000229 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000230 }
Damien Millerb38eff82000-04-01 11:09:21 +1000231
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000232 /* Return false if one of user's groups is listed in DenyGroups */
233 if (options.num_deny_groups > 0)
234 if (ga_match(options.deny_groups,
235 options.num_deny_groups)) {
236 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100237 logit("User %.100s from %.100s not allowed "
238 "because a group is listed in DenyGroups",
239 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000240 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000241 }
Damien Millerb38eff82000-04-01 11:09:21 +1000242 /*
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000243 * Return false if AllowGroups isn't empty and one of user's groups
Damien Millerb38eff82000-04-01 11:09:21 +1000244 * isn't listed there
245 */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000246 if (options.num_allow_groups > 0)
247 if (!ga_match(options.allow_groups,
248 options.num_allow_groups)) {
249 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100250 logit("User %.100s from %.100s not allowed "
251 "because none of user's groups are listed "
252 "in AllowGroups", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000253 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000254 }
255 ga_free();
Damien Millerb38eff82000-04-01 11:09:21 +1000256 }
257
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000258#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
Darren Tucker691d5232005-02-15 21:45:57 +1100259 if (!sys_auth_allowed_user(pw, &loginmsg))
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000260 return 0;
261#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000262
263 /* We found no reason not to let this user try to log on... */
264 return 1;
265}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000266
djm@openbsd.org8f574952017-06-24 06:34:38 +0000267/*
268 * Formats any key left in authctxt->auth_method_key for inclusion in
269 * auth_log()'s message. Also includes authxtct->auth_method_info if present.
270 */
271static char *
272format_method_key(Authctxt *authctxt)
Darren Tucker0acca372013-06-02 07:41:51 +1000273{
djm@openbsd.org8f574952017-06-24 06:34:38 +0000274 const struct sshkey *key = authctxt->auth_method_key;
275 const char *methinfo = authctxt->auth_method_info;
276 char *fp, *ret = NULL;
Darren Tucker0acca372013-06-02 07:41:51 +1000277
djm@openbsd.org8f574952017-06-24 06:34:38 +0000278 if (key == NULL)
279 return NULL;
Darren Tucker0acca372013-06-02 07:41:51 +1000280
djm@openbsd.org8f574952017-06-24 06:34:38 +0000281 if (key_is_cert(key)) {
282 fp = sshkey_fingerprint(key->cert->signature_key,
283 options.fingerprint_hash, SSH_FP_DEFAULT);
284 xasprintf(&ret, "%s ID %s (serial %llu) CA %s %s%s%s",
285 sshkey_type(key), key->cert->key_id,
286 (unsigned long long)key->cert->serial,
287 sshkey_type(key->cert->signature_key),
288 fp == NULL ? "(null)" : fp,
289 methinfo == NULL ? "" : ", ",
290 methinfo == NULL ? "" : methinfo);
291 free(fp);
292 } else {
293 fp = sshkey_fingerprint(key, options.fingerprint_hash,
294 SSH_FP_DEFAULT);
295 xasprintf(&ret, "%s %s%s%s", sshkey_type(key),
296 fp == NULL ? "(null)" : fp,
297 methinfo == NULL ? "" : ", ",
298 methinfo == NULL ? "" : methinfo);
299 free(fp);
300 }
301 return ret;
Darren Tucker0acca372013-06-02 07:41:51 +1000302}
303
304void
Damien Miller15b05cf2012-12-03 09:53:20 +1100305auth_log(Authctxt *authctxt, int authenticated, int partial,
Darren Tucker0acca372013-06-02 07:41:51 +1000306 const char *method, const char *submethod)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000307{
djm@openbsd.org95767262016-03-07 19:02:43 +0000308 struct ssh *ssh = active_state; /* XXX */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000309 void (*authlog) (const char *fmt,...) = verbose;
djm@openbsd.org8f574952017-06-24 06:34:38 +0000310 const char *authmsg;
311 char *extra = NULL;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000312
Damien Miller7a8f5b32006-03-31 23:14:23 +1100313 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
314 return;
315
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000316 /* Raise logging level */
317 if (authenticated == 1 ||
318 !authctxt->valid ||
Darren Tucker89413db2004-05-24 10:36:23 +1000319 authctxt->failures >= options.max_authtries / 2 ||
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000320 strcmp(method, "password") == 0)
Damien Miller2a3f20e2003-04-09 21:12:00 +1000321 authlog = logit;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000322
323 if (authctxt->postponed)
324 authmsg = "Postponed";
Damien Miller15b05cf2012-12-03 09:53:20 +1100325 else if (partial)
326 authmsg = "Partial";
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000327 else
328 authmsg = authenticated ? "Accepted" : "Failed";
329
djm@openbsd.org8f574952017-06-24 06:34:38 +0000330 if ((extra = format_method_key(authctxt)) == NULL) {
331 if (authctxt->auth_method_info != NULL)
332 extra = xstrdup(authctxt->auth_method_info);
333 }
334
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000335 authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000336 authmsg,
337 method,
Damien Miller15b05cf2012-12-03 09:53:20 +1100338 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
Darren Tucker5cb30ad2004-08-12 22:40:24 +1000339 authctxt->valid ? "" : "invalid user ",
Damien Millerf6552072001-11-12 11:06:06 +1100340 authctxt->user,
djm@openbsd.org95767262016-03-07 19:02:43 +0000341 ssh_remote_ipaddr(ssh),
342 ssh_remote_port(ssh),
djm@openbsd.org8f574952017-06-24 06:34:38 +0000343 extra != NULL ? ": " : "",
344 extra != NULL ? extra : "");
345
346 free(extra);
Ben Lindstrome06eb682002-07-04 00:27:21 +0000347
Darren Tucker97363a82003-05-02 23:42:25 +1000348#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker2fba9932005-02-02 23:30:24 +1100349 if (authenticated == 0 && !authctxt->postponed &&
350 (strcmp(method, "password") == 0 ||
Darren Tucker40d9a632005-02-04 15:19:44 +1100351 strncmp(method, "keyboard-interactive", 20) == 0 ||
352 strcmp(method, "challenge-response") == 0))
Darren Tucker42d9dc72005-02-02 17:10:11 +1100353 record_failed_login(authctxt->user,
Darren Tucker885fb2a2016-03-08 11:58:43 +1100354 auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
Darren Tucker26d4e192006-08-30 22:33:09 +1000355# ifdef WITH_AIXAUTHENTICATE
356 if (authenticated)
357 sys_auth_record_login(authctxt->user,
Darren Tucker885fb2a2016-03-08 11:58:43 +1100358 auth_get_canonical_hostname(ssh, options.use_dns), "ssh",
359 &loginmsg);
Darren Tucker26d4e192006-08-30 22:33:09 +1000360# endif
Darren Tucker97363a82003-05-02 23:42:25 +1000361#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100362#ifdef SSH_AUDIT_EVENTS
Darren Tuckerf14b2aa2006-05-21 18:26:40 +1000363 if (authenticated == 0 && !authctxt->postponed)
364 audit_event(audit_classify_auth(method));
Darren Tucker269a1ea2005-02-03 00:20:53 +1100365#endif
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000366}
367
Damien Miller686feb52014-07-03 21:29:38 +1000368
369void
370auth_maxtries_exceeded(Authctxt *authctxt)
371{
djm@openbsd.org95767262016-03-07 19:02:43 +0000372 struct ssh *ssh = active_state; /* XXX */
373
djm@openbsd.org6f621602015-02-25 17:29:38 +0000374 error("maximum authentication attempts exceeded for "
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000375 "%s%.100s from %.200s port %d ssh2",
Damien Miller686feb52014-07-03 21:29:38 +1000376 authctxt->valid ? "" : "invalid user ",
377 authctxt->user,
djm@openbsd.org95767262016-03-07 19:02:43 +0000378 ssh_remote_ipaddr(ssh),
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000379 ssh_remote_port(ssh));
djm@openbsd.org6f621602015-02-25 17:29:38 +0000380 packet_disconnect("Too many authentication failures");
Damien Miller686feb52014-07-03 21:29:38 +1000381 /* NOTREACHED */
382}
383
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000384/*
Ben Lindstromd8a90212001-02-15 03:08:27 +0000385 * Check whether root logins are disallowed.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000386 */
387int
Damien Miller15b05cf2012-12-03 09:53:20 +1100388auth_root_allowed(const char *method)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000389{
djm@openbsd.org95767262016-03-07 19:02:43 +0000390 struct ssh *ssh = active_state; /* XXX */
391
Ben Lindstromd8a90212001-02-15 03:08:27 +0000392 switch (options.permit_root_login) {
393 case PERMIT_YES:
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000394 return 1;
Ben Lindstromd8a90212001-02-15 03:08:27 +0000395 case PERMIT_NO_PASSWD:
deraadt@openbsd.org1dc8d932015-08-06 14:53:21 +0000396 if (strcmp(method, "publickey") == 0 ||
397 strcmp(method, "hostbased") == 0 ||
djm@openbsd.org32a18192015-08-21 03:42:19 +0000398 strcmp(method, "gssapi-with-mic") == 0)
Ben Lindstromd8a90212001-02-15 03:08:27 +0000399 return 1;
400 break;
401 case PERMIT_FORCED_ONLY:
402 if (forced_command) {
Damien Miller996acd22003-04-09 20:59:48 +1000403 logit("Root login accepted for forced command.");
Ben Lindstromd8a90212001-02-15 03:08:27 +0000404 return 1;
405 }
406 break;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000407 }
djm@openbsd.org95767262016-03-07 19:02:43 +0000408 logit("ROOT LOGIN REFUSED FROM %.200s port %d",
409 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
Ben Lindstromd8a90212001-02-15 03:08:27 +0000410 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000411}
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000412
413
414/*
415 * Given a template and a passwd structure, build a filename
416 * by substituting % tokenised options. Currently, %% becomes '%',
417 * %h becomes the home directory and %u the username.
418 *
419 * This returns a buffer allocated by xmalloc.
420 */
Damien Millerd8478b62011-05-29 21:39:36 +1000421char *
Damien Miller6476cad2005-06-16 13:18:34 +1000422expand_authorized_keys(const char *filename, struct passwd *pw)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000423{
deraadt@openbsd.org087266e2015-01-20 23:14:00 +0000424 char *file, ret[PATH_MAX];
Damien Miller07d86be2006-03-26 14:19:21 +1100425 int i;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000426
Damien Miller6476cad2005-06-16 13:18:34 +1000427 file = percent_expand(filename, "h", pw->pw_dir,
428 "u", pw->pw_name, (char *)NULL);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000429
430 /*
431 * Ensure that filename starts anchored. If not, be backward
432 * compatible and prepend the '%h/'
433 */
Damien Miller6476cad2005-06-16 13:18:34 +1000434 if (*file == '/')
435 return (file);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000436
Damien Miller07d86be2006-03-26 14:19:21 +1100437 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
438 if (i < 0 || (size_t)i >= sizeof(ret))
Damien Miller6476cad2005-06-16 13:18:34 +1000439 fatal("expand_authorized_keys: path too long");
Darren Tuckera627d422013-06-02 07:31:17 +1000440 free(file);
Damien Miller07d86be2006-03-26 14:19:21 +1100441 return (xstrdup(ret));
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000442}
443
444char *
Damien Miller30da3442010-05-10 11:58:03 +1000445authorized_principals_file(struct passwd *pw)
446{
djm@openbsd.org7e8528c2015-05-01 04:17:51 +0000447 if (options.authorized_principals_file == NULL)
Damien Miller30da3442010-05-10 11:58:03 +1000448 return NULL;
449 return expand_authorized_keys(options.authorized_principals_file, pw);
450}
451
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000452/* return ok if key exists in sysfile or userfile */
453HostStatus
markus@openbsd.org54d90ac2017-05-30 08:52:19 +0000454check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000455 const char *sysfile, const char *userfile)
456{
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000457 char *user_hostfile;
458 struct stat st;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000459 HostStatus host_status;
Damien Millerd925dcd2010-12-01 12:21:51 +1100460 struct hostkeys *hostkeys;
461 const struct hostkey_entry *found;
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000462
Damien Millerd925dcd2010-12-01 12:21:51 +1100463 hostkeys = init_hostkeys();
464 load_hostkeys(hostkeys, host, sysfile);
465 if (userfile != NULL) {
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000466 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
467 if (options.strict_modes &&
468 (stat(user_hostfile, &st) == 0) &&
469 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
Damien Miller9f0f5c62001-12-21 14:45:46 +1100470 (st.st_mode & 022) != 0)) {
Damien Miller996acd22003-04-09 20:59:48 +1000471 logit("Authentication refused for %.100s: "
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000472 "bad owner or modes for %.200s",
473 pw->pw_name, user_hostfile);
Damien Miller48147d62010-06-26 09:39:25 +1000474 auth_debug_add("Ignored %.200s: bad ownership or modes",
475 user_hostfile);
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000476 } else {
477 temporarily_use_uid(pw);
Damien Millerd925dcd2010-12-01 12:21:51 +1100478 load_hostkeys(hostkeys, host, user_hostfile);
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000479 restore_uid();
480 }
Darren Tuckera627d422013-06-02 07:31:17 +1000481 free(user_hostfile);
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000482 }
Damien Millerd925dcd2010-12-01 12:21:51 +1100483 host_status = check_key_in_hostkeys(hostkeys, key, &found);
484 if (host_status == HOST_REVOKED)
485 error("WARNING: revoked key for %s attempted authentication",
486 found->host);
487 else if (host_status == HOST_OK)
488 debug("%s: key for %s found at %s:%ld", __func__,
489 found->host, found->file, found->line);
490 else
491 debug("%s: key for host %s not found", __func__, host);
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000492
Damien Millerd925dcd2010-12-01 12:21:51 +1100493 free_hostkeys(hostkeys);
494
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000495 return host_status;
496}
497
Damien Miller30da3442010-05-10 11:58:03 +1000498static FILE *
499auth_openfile(const char *file, struct passwd *pw, int strict_modes,
500 int log_missing, char *file_type)
Darren Tucker33c787f2008-07-02 22:37:30 +1000501{
502 char line[1024];
503 struct stat st;
504 int fd;
505 FILE *f;
506
Darren Tucker43551522010-01-10 19:27:17 +1100507 if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
Damien Miller30da3442010-05-10 11:58:03 +1000508 if (log_missing || errno != ENOENT)
509 debug("Could not open %s '%s': %s", file_type, file,
Darren Tucker43551522010-01-10 19:27:17 +1100510 strerror(errno));
Darren Tucker33c787f2008-07-02 22:37:30 +1000511 return NULL;
Darren Tucker43551522010-01-10 19:27:17 +1100512 }
Darren Tucker33c787f2008-07-02 22:37:30 +1000513
514 if (fstat(fd, &st) < 0) {
515 close(fd);
516 return NULL;
517 }
518 if (!S_ISREG(st.st_mode)) {
Damien Miller30da3442010-05-10 11:58:03 +1000519 logit("User %s %s %s is not a regular file",
520 pw->pw_name, file_type, file);
Darren Tucker33c787f2008-07-02 22:37:30 +1000521 close(fd);
522 return NULL;
523 }
524 unset_nonblock(fd);
525 if ((f = fdopen(fd, "r")) == NULL) {
526 close(fd);
527 return NULL;
528 }
Damien Miller6a740e72010-12-01 12:01:51 +1100529 if (strict_modes &&
djm@openbsd.orgde4ae072017-08-18 05:36:45 +0000530 safe_path_fd(fileno(f), file, pw, line, sizeof(line)) != 0) {
Darren Tucker33c787f2008-07-02 22:37:30 +1000531 fclose(f);
532 logit("Authentication refused: %s", line);
Damien Miller48147d62010-06-26 09:39:25 +1000533 auth_debug_add("Ignored %s: %s", file_type, line);
Darren Tucker33c787f2008-07-02 22:37:30 +1000534 return NULL;
535 }
536
537 return f;
538}
539
Damien Miller30da3442010-05-10 11:58:03 +1000540
541FILE *
542auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
543{
544 return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
545}
546
547FILE *
548auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
549{
550 return auth_openfile(file, pw, strict_modes, 0,
551 "authorized principals");
552}
553
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000554struct passwd *
555getpwnamallow(const char *user)
556{
djm@openbsd.org95767262016-03-07 19:02:43 +0000557 struct ssh *ssh = active_state; /* XXX */
Ben Lindstromb481e132002-03-22 01:35:47 +0000558#ifdef HAVE_LOGIN_CAP
559 extern login_cap_t *lc;
560#ifdef BSD_AUTH
561 auth_session_t *as;
562#endif
563#endif
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000564 struct passwd *pw;
Darren Tuckerfbcf8272012-05-19 19:37:01 +1000565 struct connection_info *ci = get_connection_info(1, options.use_dns);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000566
Darren Tuckerfbcf8272012-05-19 19:37:01 +1000567 ci->user = user;
568 parse_server_match_config(&options, ci);
djm@openbsd.org54cd41a2017-05-17 01:24:17 +0000569 log_change_level(options.log_level);
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000570 process_permitopen(ssh, &options);
Darren Tucker45150472006-07-12 22:34:17 +1000571
Darren Tuckerb3d20a32010-03-07 11:56:59 +1100572#if defined(_AIX) && defined(HAVE_SETAUTHDB)
573 aix_setauthdb(user);
574#endif
575
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000576 pw = getpwnam(user);
Darren Tuckerb3d20a32010-03-07 11:56:59 +1100577
578#if defined(_AIX) && defined(HAVE_SETAUTHDB)
579 aix_restoreauthdb();
580#endif
Damien Milleracc9b292010-03-01 04:36:54 +1100581#ifdef HAVE_CYGWIN
582 /*
583 * Windows usernames are case-insensitive. To avoid later problems
584 * when trying to match the username, the user is only allowed to
585 * login if the username is given in the same case as stored in the
586 * user database.
587 */
588 if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
589 logit("Login name %.100s does not match stored username %.100s",
590 user, pw->pw_name);
591 pw = NULL;
592 }
593#endif
Damien Miller6f0a1882002-09-22 01:26:51 +1000594 if (pw == NULL) {
djm@openbsd.org95767262016-03-07 19:02:43 +0000595 logit("Invalid user %.100s from %.100s port %d",
596 user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
Darren Tucker97363a82003-05-02 23:42:25 +1000597#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker42d9dc72005-02-02 17:10:11 +1100598 record_failed_login(user,
Darren Tucker885fb2a2016-03-08 11:58:43 +1100599 auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
Ben Lindstromf5397c02002-11-09 16:11:10 +0000600#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100601#ifdef SSH_AUDIT_EVENTS
602 audit_event(SSH_INVALID_USER);
603#endif /* SSH_AUDIT_EVENTS */
Damien Miller6f0a1882002-09-22 01:26:51 +1000604 return (NULL);
605 }
606 if (!allowed_user(pw))
Ben Lindstromb481e132002-03-22 01:35:47 +0000607 return (NULL);
608#ifdef HAVE_LOGIN_CAP
609 if ((lc = login_getclass(pw->pw_class)) == NULL) {
610 debug("unable to get login class: %s", user);
611 return (NULL);
612 }
613#ifdef BSD_AUTH
614 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
Damien Miller13e35a02002-05-22 14:04:11 +1000615 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
Ben Lindstromb481e132002-03-22 01:35:47 +0000616 debug("Approval failure for %s", user);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000617 pw = NULL;
Ben Lindstromb481e132002-03-22 01:35:47 +0000618 }
619 if (as != NULL)
620 auth_close(as);
621#endif
622#endif
Ben Lindstromf34e4eb2002-03-22 03:08:30 +0000623 if (pw != NULL)
624 return (pwcopy(pw));
625 return (NULL);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000626}
Ben Lindstroma574cda2002-05-15 16:16:14 +0000627
Damien Miller1aed65e2010-03-04 21:53:35 +1100628/* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
629int
markus@openbsd.org54d90ac2017-05-30 08:52:19 +0000630auth_key_is_revoked(struct sshkey *key)
Damien Miller1aed65e2010-03-04 21:53:35 +1100631{
djm@openbsd.org5e39a492014-12-04 02:24:32 +0000632 char *fp = NULL;
633 int r;
Damien Miller1aed65e2010-03-04 21:53:35 +1100634
635 if (options.revoked_keys_file == NULL)
636 return 0;
djm@openbsd.org56d1c832014-12-21 22:27:55 +0000637 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
638 SSH_FP_DEFAULT)) == NULL) {
djm@openbsd.org5e39a492014-12-04 02:24:32 +0000639 r = SSH_ERR_ALLOC_FAIL;
640 error("%s: fingerprint key: %s", __func__, ssh_err(r));
641 goto out;
642 }
643
644 r = sshkey_check_revoked(key, options.revoked_keys_file);
645 switch (r) {
Damien Millerf3747bf2013-01-18 11:44:04 +1100646 case 0:
djm@openbsd.org5e39a492014-12-04 02:24:32 +0000647 break; /* not revoked */
648 case SSH_ERR_KEY_REVOKED:
649 error("Authentication key %s %s revoked by file %s",
650 sshkey_type(key), fp, options.revoked_keys_file);
651 goto out;
Damien Millerf3747bf2013-01-18 11:44:04 +1100652 default:
djm@openbsd.org5e39a492014-12-04 02:24:32 +0000653 error("Error checking authentication key %s %s in "
654 "revoked keys file %s: %s", sshkey_type(key), fp,
655 options.revoked_keys_file, ssh_err(r));
656 goto out;
Damien Millerf3747bf2013-01-18 11:44:04 +1100657 }
djm@openbsd.org5e39a492014-12-04 02:24:32 +0000658
659 /* Success */
660 r = 0;
661
662 out:
663 free(fp);
664 return r == 0 ? 0 : 1;
Damien Miller1aed65e2010-03-04 21:53:35 +1100665}
666
Ben Lindstroma574cda2002-05-15 16:16:14 +0000667void
668auth_debug_add(const char *fmt,...)
669{
670 char buf[1024];
671 va_list args;
672
673 if (!auth_debug_init)
674 return;
675
676 va_start(args, fmt);
677 vsnprintf(buf, sizeof(buf), fmt, args);
678 va_end(args);
679 buffer_put_cstring(&auth_debug, buf);
680}
681
682void
683auth_debug_send(void)
684{
685 char *msg;
686
687 if (!auth_debug_init)
688 return;
689 while (buffer_len(&auth_debug)) {
690 msg = buffer_get_string(&auth_debug, NULL);
691 packet_send_debug("%s", msg);
Darren Tuckera627d422013-06-02 07:31:17 +1000692 free(msg);
Ben Lindstroma574cda2002-05-15 16:16:14 +0000693 }
694}
695
696void
697auth_debug_reset(void)
698{
699 if (auth_debug_init)
700 buffer_clear(&auth_debug);
701 else {
702 buffer_init(&auth_debug);
703 auth_debug_init = 1;
704 }
705}
Damien Miller856f0be2003-09-03 07:32:45 +1000706
707struct passwd *
708fakepw(void)
709{
710 static struct passwd fake;
711
712 memset(&fake, 0, sizeof(fake));
713 fake.pw_name = "NOUSER";
714 fake.pw_passwd =
Damien Miller787b2ec2003-11-21 23:56:47 +1100715 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
Damien Miller6332da22013-04-23 14:25:52 +1000716#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
Damien Miller856f0be2003-09-03 07:32:45 +1000717 fake.pw_gecos = "NOUSER";
Damien Miller6332da22013-04-23 14:25:52 +1000718#endif
Damien Miller143c2ef2006-12-05 09:08:54 +1100719 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
720 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
Damien Miller6332da22013-04-23 14:25:52 +1000721#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
Damien Miller856f0be2003-09-03 07:32:45 +1000722 fake.pw_class = "";
723#endif
724 fake.pw_dir = "/nonexist";
725 fake.pw_shell = "/nonexist";
726
727 return (&fake);
728}
djm@openbsd.org95767262016-03-07 19:02:43 +0000729
730/*
731 * Returns the remote DNS hostname as a string. The returned string must not
732 * be freed. NB. this will usually trigger a DNS query the first time it is
733 * called.
734 * This function does additional checks on the hostname to mitigate some
735 * attacks on legacy rhosts-style authentication.
736 * XXX is RhostsRSAAuthentication vulnerable to these?
737 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
738 */
739
740static char *
741remote_hostname(struct ssh *ssh)
742{
743 struct sockaddr_storage from;
744 socklen_t fromlen;
745 struct addrinfo hints, *ai, *aitop;
746 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
747 const char *ntop = ssh_remote_ipaddr(ssh);
748
749 /* Get IP address of client. */
750 fromlen = sizeof(from);
751 memset(&from, 0, sizeof(from));
752 if (getpeername(ssh_packet_get_connection_in(ssh),
753 (struct sockaddr *)&from, &fromlen) < 0) {
754 debug("getpeername failed: %.100s", strerror(errno));
755 return strdup(ntop);
756 }
757
758 ipv64_normalise_mapped(&from, &fromlen);
759 if (from.ss_family == AF_INET6)
760 fromlen = sizeof(struct sockaddr_in6);
761
762 debug3("Trying to reverse map address %.100s.", ntop);
763 /* Map the IP address to a host name. */
764 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
765 NULL, 0, NI_NAMEREQD) != 0) {
766 /* Host name not found. Use ip address. */
767 return strdup(ntop);
768 }
769
770 /*
771 * if reverse lookup result looks like a numeric hostname,
772 * someone is trying to trick us by PTR record like following:
773 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
774 */
775 memset(&hints, 0, sizeof(hints));
776 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
777 hints.ai_flags = AI_NUMERICHOST;
778 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
779 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
780 name, ntop);
781 freeaddrinfo(ai);
782 return strdup(ntop);
783 }
784
785 /* Names are stored in lowercase. */
786 lowercase(name);
787
788 /*
789 * Map it back to an IP address and check that the given
790 * address actually is an address of this host. This is
791 * necessary because anyone with access to a name server can
792 * define arbitrary names for an IP address. Mapping from
793 * name to IP address can be trusted better (but can still be
794 * fooled if the intruder has access to the name server of
795 * the domain).
796 */
797 memset(&hints, 0, sizeof(hints));
798 hints.ai_family = from.ss_family;
799 hints.ai_socktype = SOCK_STREAM;
800 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
801 logit("reverse mapping checking getaddrinfo for %.700s "
dtucker@openbsd.orge690fe82016-06-15 00:40:40 +0000802 "[%s] failed.", name, ntop);
djm@openbsd.org95767262016-03-07 19:02:43 +0000803 return strdup(ntop);
804 }
805 /* Look for the address from the list of addresses. */
806 for (ai = aitop; ai; ai = ai->ai_next) {
807 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
808 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
809 (strcmp(ntop, ntop2) == 0))
810 break;
811 }
812 freeaddrinfo(aitop);
813 /* If we reached the end of the list, the address was not there. */
814 if (ai == NULL) {
815 /* Address not found for the host name. */
816 logit("Address %.100s maps to %.600s, but this does not "
dtucker@openbsd.orge690fe82016-06-15 00:40:40 +0000817 "map back to the address.", ntop, name);
djm@openbsd.org95767262016-03-07 19:02:43 +0000818 return strdup(ntop);
819 }
820 return strdup(name);
821}
822
823/*
824 * Return the canonical name of the host in the other side of the current
825 * connection. The host name is cached, so it is efficient to call this
826 * several times.
827 */
828
829const char *
830auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
831{
832 static char *dnsname;
833
834 if (!use_dns)
835 return ssh_remote_ipaddr(ssh);
836 else if (dnsname != NULL)
837 return dnsname;
838 else {
839 dnsname = remote_hostname(ssh);
840 return dnsname;
841 }
842}