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Damien Miller48147d62010-06-26 09:39:25 +10001/* $OpenBSD: auth.c,v 1.88 2010/06/22 04:49:47 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>
Damien Miller8dbffe72006-08-05 11:02:17 +100030#include <sys/param.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
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000046#ifdef HAVE_LIBGEN_H
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000047#include <libgen.h>
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000048#endif
Darren Tucker5d196262006-07-12 22:15:16 +100049#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100050#include <stdio.h>
Damien Millere3476ed2006-07-24 14:13:33 +100051#include <string.h>
Damien Miller7acf5502008-07-09 20:54:37 +100052#include <unistd.h>
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000053
Ben Lindstrom226cfa02001-01-22 05:34:40 +000054#include "xmalloc.h"
55#include "match.h"
56#include "groupaccess.h"
57#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100058#include "buffer.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 Lindstrom7ebb6352002-03-22 03:04:08 +000066#include "misc.h"
Ben Lindstroma574cda2002-05-15 16:16:14 +000067#include "packet.h"
Darren Tucker42d9dc72005-02-02 17:10:11 +110068#include "loginrec.h"
Damien Millerd7834352006-08-05 12:39:39 +100069#ifdef GSSAPI
70#include "ssh-gss.h"
71#endif
Damien Miller1aed65e2010-03-04 21:53:35 +110072#include "authfile.h"
Darren Tucker269a1ea2005-02-03 00:20:53 +110073#include "monitor_wrap.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100074
Damien Millerb38eff82000-04-01 11:09:21 +100075/* import */
76extern ServerOptions options;
Damien Miller7a8f5b32006-03-31 23:14:23 +110077extern int use_privsep;
Darren Tuckerb9aa0a02003-07-08 22:59:59 +100078extern Buffer loginmsg;
Damien Miller6433df02006-09-07 10:36:43 +100079extern struct passwd *privsep_pw;
Damien Millerb38eff82000-04-01 11:09:21 +100080
Ben Lindstroma574cda2002-05-15 16:16:14 +000081/* Debugging messages */
82Buffer auth_debug;
83int auth_debug_init;
84
Damien Millerb38eff82000-04-01 11:09:21 +100085/*
Kevin Steves7b61cfa2001-01-14 19:11:00 +000086 * Check if the user is allowed to log in via ssh. If user is listed
87 * in DenyUsers or one of user's groups is listed in DenyGroups, false
88 * will be returned. If AllowUsers isn't empty and user isn't listed
89 * there, or if AllowGroups isn't empty and one of user's groups isn't
90 * listed there, false will be returned.
Damien Millerb38eff82000-04-01 11:09:21 +100091 * If the user's shell is not executable, false will be returned.
Damien Miller4af51302000-04-16 11:18:38 +100092 * Otherwise true is returned.
Damien Millerb38eff82000-04-01 11:09:21 +100093 */
Damien Millereba71ba2000-04-29 23:57:08 +100094int
Damien Millerb38eff82000-04-01 11:09:21 +100095allowed_user(struct passwd * pw)
96{
97 struct stat st;
Darren Tucker43a0dc62003-08-26 14:22:12 +100098 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
Damien Millereccb9de2005-06-17 12:59:34 +100099 u_int i;
Darren Tucker15ee7482004-02-22 09:43:15 +1100100#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000101 struct spwd *spw = NULL;
Tim Rice458c6bf2003-01-08 20:04:27 -0800102#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000103
104 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000105 if (!pw || !pw->pw_name)
Damien Millerb38eff82000-04-01 11:09:21 +1000106 return 0;
107
Darren Tucker15ee7482004-02-22 09:43:15 +1100108#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000109 if (!options.use_pam)
110 spw = getspnam(pw->pw_name);
111#ifdef HAS_SHADOW_EXPIRE
Darren Tucker15ee7482004-02-22 09:43:15 +1100112 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
113 return 0;
Darren Tuckere41bba52003-08-25 11:51:19 +1000114#endif /* HAS_SHADOW_EXPIRE */
Darren Tucker15ee7482004-02-22 09:43:15 +1100115#endif /* USE_SHADOW */
Darren Tuckere41bba52003-08-25 11:51:19 +1000116
Damien Millera8e06ce2003-11-21 23:48:55 +1100117 /* grab passwd field for locked account check */
Damien Miller22989f12008-07-05 08:59:43 +1000118 passwd = pw->pw_passwd;
Darren Tucker15ee7482004-02-22 09:43:15 +1100119#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000120 if (spw != NULL)
Tim Rice99203ec2007-03-26 09:35:28 -0700121#ifdef USE_LIBIAF
Tim Rice2291c002005-08-26 13:15:19 -0700122 passwd = get_iaf_password(pw);
123#else
Darren Tuckere41bba52003-08-25 11:51:19 +1000124 passwd = spw->sp_pwdp;
Tim Rice99203ec2007-03-26 09:35:28 -0700125#endif /* USE_LIBIAF */
Damien Miller06817f92003-01-07 23:55:59 +1100126#endif
127
Damien Millera8e06ce2003-11-21 23:48:55 +1100128 /* check for locked account */
Darren Tucker43a0dc62003-08-26 14:22:12 +1000129 if (!options.use_pam && passwd && *passwd) {
Darren Tuckere41bba52003-08-25 11:51:19 +1000130 int locked = 0;
131
132#ifdef LOCKED_PASSWD_STRING
133 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
134 locked = 1;
135#endif
136#ifdef LOCKED_PASSWD_PREFIX
137 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
138 strlen(LOCKED_PASSWD_PREFIX)) == 0)
139 locked = 1;
140#endif
141#ifdef LOCKED_PASSWD_SUBSTR
142 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
143 locked = 1;
144#endif
Tim Rice99203ec2007-03-26 09:35:28 -0700145#ifdef USE_LIBIAF
Tim Rice66fd2172005-08-31 09:59:49 -0700146 free(passwd);
Tim Rice99203ec2007-03-26 09:35:28 -0700147#endif /* USE_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000148 if (locked) {
149 logit("User %.100s not allowed because account is locked",
150 pw->pw_name);
151 return 0;
152 }
153 }
154
Damien Milleref7df542000-05-19 00:03:23 +1000155 /*
Damien Miller47cf16b2010-02-12 09:25:29 +1100156 * Deny if shell does not exist or is not executable unless we
157 * are chrooting.
Damien Milleref7df542000-05-19 00:03:23 +1000158 */
Damien Miller47cf16b2010-02-12 09:25:29 +1100159 if (options.chroot_directory == NULL ||
160 strcasecmp(options.chroot_directory, "none") == 0) {
161 char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
162 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
Darren Tucker94881d82010-01-15 11:44:46 +1100163
Damien Miller47cf16b2010-02-12 09:25:29 +1100164 if (stat(shell, &st) != 0) {
165 logit("User %.100s not allowed because shell %.100s "
166 "does not exist", pw->pw_name, shell);
167 xfree(shell);
168 return 0;
169 }
170 if (S_ISREG(st.st_mode) == 0 ||
171 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
172 logit("User %.100s not allowed because shell %.100s "
173 "is not executable", pw->pw_name, shell);
174 xfree(shell);
175 return 0;
176 }
Darren Tucker94881d82010-01-15 11:44:46 +1100177 xfree(shell);
Darren Tucker94881d82010-01-15 11:44:46 +1100178 }
Damien Milleref7df542000-05-19 00:03:23 +1000179
Darren Tuckera8f553d2005-03-14 23:17:27 +1100180 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
181 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Damien Miller3a961dc2003-06-03 10:25:48 +1000182 hostname = get_canonical_hostname(options.use_dns);
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000183 ipaddr = get_remote_ipaddr();
184 }
185
Damien Millerb38eff82000-04-01 11:09:21 +1000186 /* Return false if user is listed in DenyUsers */
187 if (options.num_deny_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000188 for (i = 0; i < options.num_deny_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000189 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000190 options.deny_users[i])) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100191 logit("User %.100s from %.100s not allowed "
192 "because listed in DenyUsers",
193 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000194 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000195 }
Damien Millerb38eff82000-04-01 11:09:21 +1000196 }
197 /* Return false if AllowUsers isn't empty and user isn't listed there */
198 if (options.num_allow_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000199 for (i = 0; i < options.num_allow_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000200 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom60260022001-07-04 04:56:44 +0000201 options.allow_users[i]))
Damien Millerb38eff82000-04-01 11:09:21 +1000202 break;
203 /* i < options.num_allow_users iff we break for loop */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000204 if (i >= options.num_allow_users) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100205 logit("User %.100s from %.100s not allowed because "
206 "not listed in AllowUsers", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000207 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000208 }
Damien Millerb38eff82000-04-01 11:09:21 +1000209 }
Damien Millerb38eff82000-04-01 11:09:21 +1000210 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000211 /* Get the user's group access list (primary and supplementary) */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000212 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100213 logit("User %.100s from %.100s not allowed because "
214 "not in any group", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000215 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000216 }
Damien Millerb38eff82000-04-01 11:09:21 +1000217
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000218 /* Return false if one of user's groups is listed in DenyGroups */
219 if (options.num_deny_groups > 0)
220 if (ga_match(options.deny_groups,
221 options.num_deny_groups)) {
222 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100223 logit("User %.100s from %.100s not allowed "
224 "because a group is listed in DenyGroups",
225 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000226 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000227 }
Damien Millerb38eff82000-04-01 11:09:21 +1000228 /*
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000229 * Return false if AllowGroups isn't empty and one of user's groups
Damien Millerb38eff82000-04-01 11:09:21 +1000230 * isn't listed there
231 */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000232 if (options.num_allow_groups > 0)
233 if (!ga_match(options.allow_groups,
234 options.num_allow_groups)) {
235 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100236 logit("User %.100s from %.100s not allowed "
237 "because none of user's groups are listed "
238 "in AllowGroups", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000239 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000240 }
241 ga_free();
Damien Millerb38eff82000-04-01 11:09:21 +1000242 }
243
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000244#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
Darren Tucker691d5232005-02-15 21:45:57 +1100245 if (!sys_auth_allowed_user(pw, &loginmsg))
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000246 return 0;
247#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000248
249 /* We found no reason not to let this user try to log on... */
250 return 1;
251}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000252
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000253void
254auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
255{
256 void (*authlog) (const char *fmt,...) = verbose;
257 char *authmsg;
258
Damien Miller7a8f5b32006-03-31 23:14:23 +1100259 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
260 return;
261
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000262 /* Raise logging level */
263 if (authenticated == 1 ||
264 !authctxt->valid ||
Darren Tucker89413db2004-05-24 10:36:23 +1000265 authctxt->failures >= options.max_authtries / 2 ||
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000266 strcmp(method, "password") == 0)
Damien Miller2a3f20e2003-04-09 21:12:00 +1000267 authlog = logit;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000268
269 if (authctxt->postponed)
270 authmsg = "Postponed";
271 else
272 authmsg = authenticated ? "Accepted" : "Failed";
273
274 authlog("%s %s for %s%.100s from %.200s port %d%s",
275 authmsg,
276 method,
Darren Tucker5cb30ad2004-08-12 22:40:24 +1000277 authctxt->valid ? "" : "invalid user ",
Damien Millerf6552072001-11-12 11:06:06 +1100278 authctxt->user,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000279 get_remote_ipaddr(),
280 get_remote_port(),
281 info);
Ben Lindstrome06eb682002-07-04 00:27:21 +0000282
Darren Tucker97363a82003-05-02 23:42:25 +1000283#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker2fba9932005-02-02 23:30:24 +1100284 if (authenticated == 0 && !authctxt->postponed &&
285 (strcmp(method, "password") == 0 ||
Darren Tucker40d9a632005-02-04 15:19:44 +1100286 strncmp(method, "keyboard-interactive", 20) == 0 ||
287 strcmp(method, "challenge-response") == 0))
Darren Tucker42d9dc72005-02-02 17:10:11 +1100288 record_failed_login(authctxt->user,
289 get_canonical_hostname(options.use_dns), "ssh");
Darren Tucker26d4e192006-08-30 22:33:09 +1000290# ifdef WITH_AIXAUTHENTICATE
291 if (authenticated)
292 sys_auth_record_login(authctxt->user,
293 get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
294# endif
Darren Tucker97363a82003-05-02 23:42:25 +1000295#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100296#ifdef SSH_AUDIT_EVENTS
Darren Tuckerf14b2aa2006-05-21 18:26:40 +1000297 if (authenticated == 0 && !authctxt->postponed)
298 audit_event(audit_classify_auth(method));
Darren Tucker269a1ea2005-02-03 00:20:53 +1100299#endif
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000300}
301
302/*
Ben Lindstromd8a90212001-02-15 03:08:27 +0000303 * Check whether root logins are disallowed.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000304 */
305int
Ben Lindstromd8a90212001-02-15 03:08:27 +0000306auth_root_allowed(char *method)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000307{
Ben Lindstromd8a90212001-02-15 03:08:27 +0000308 switch (options.permit_root_login) {
309 case PERMIT_YES:
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000310 return 1;
Ben Lindstromd8a90212001-02-15 03:08:27 +0000311 case PERMIT_NO_PASSWD:
312 if (strcmp(method, "password") != 0)
313 return 1;
314 break;
315 case PERMIT_FORCED_ONLY:
316 if (forced_command) {
Damien Miller996acd22003-04-09 20:59:48 +1000317 logit("Root login accepted for forced command.");
Ben Lindstromd8a90212001-02-15 03:08:27 +0000318 return 1;
319 }
320 break;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000321 }
Damien Miller996acd22003-04-09 20:59:48 +1000322 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
Ben Lindstromd8a90212001-02-15 03:08:27 +0000323 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000324}
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000325
326
327/*
328 * Given a template and a passwd structure, build a filename
329 * by substituting % tokenised options. Currently, %% becomes '%',
330 * %h becomes the home directory and %u the username.
331 *
332 * This returns a buffer allocated by xmalloc.
333 */
Damien Miller6476cad2005-06-16 13:18:34 +1000334static char *
335expand_authorized_keys(const char *filename, struct passwd *pw)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000336{
Damien Miller07d86be2006-03-26 14:19:21 +1100337 char *file, ret[MAXPATHLEN];
338 int i;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000339
Damien Miller6476cad2005-06-16 13:18:34 +1000340 file = percent_expand(filename, "h", pw->pw_dir,
341 "u", pw->pw_name, (char *)NULL);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000342
343 /*
344 * Ensure that filename starts anchored. If not, be backward
345 * compatible and prepend the '%h/'
346 */
Damien Miller6476cad2005-06-16 13:18:34 +1000347 if (*file == '/')
348 return (file);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000349
Damien Miller07d86be2006-03-26 14:19:21 +1100350 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
351 if (i < 0 || (size_t)i >= sizeof(ret))
Damien Miller6476cad2005-06-16 13:18:34 +1000352 fatal("expand_authorized_keys: path too long");
Damien Miller6476cad2005-06-16 13:18:34 +1000353 xfree(file);
Damien Miller07d86be2006-03-26 14:19:21 +1100354 return (xstrdup(ret));
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000355}
356
357char *
358authorized_keys_file(struct passwd *pw)
359{
Damien Miller6476cad2005-06-16 13:18:34 +1000360 return expand_authorized_keys(options.authorized_keys_file, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000361}
362
363char *
364authorized_keys_file2(struct passwd *pw)
365{
Damien Miller6476cad2005-06-16 13:18:34 +1000366 return expand_authorized_keys(options.authorized_keys_file2, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000367}
368
Damien Miller30da3442010-05-10 11:58:03 +1000369char *
370authorized_principals_file(struct passwd *pw)
371{
372 if (options.authorized_principals_file == NULL)
373 return NULL;
374 return expand_authorized_keys(options.authorized_principals_file, pw);
375}
376
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000377/* return ok if key exists in sysfile or userfile */
378HostStatus
379check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
380 const char *sysfile, const char *userfile)
381{
382 Key *found;
383 char *user_hostfile;
384 struct stat st;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000385 HostStatus host_status;
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000386
387 /* Check if we know the host and its host key. */
388 found = key_new(key->type);
389 host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
390
391 if (host_status != HOST_OK && userfile != NULL) {
392 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
393 if (options.strict_modes &&
394 (stat(user_hostfile, &st) == 0) &&
395 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
Damien Miller9f0f5c62001-12-21 14:45:46 +1100396 (st.st_mode & 022) != 0)) {
Damien Miller996acd22003-04-09 20:59:48 +1000397 logit("Authentication refused for %.100s: "
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000398 "bad owner or modes for %.200s",
399 pw->pw_name, user_hostfile);
Damien Miller48147d62010-06-26 09:39:25 +1000400 auth_debug_add("Ignored %.200s: bad ownership or modes",
401 user_hostfile);
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000402 } else {
403 temporarily_use_uid(pw);
404 host_status = check_host_in_hostfile(user_hostfile,
405 host, key, found, NULL);
406 restore_uid();
407 }
408 xfree(user_hostfile);
409 }
410 key_free(found);
411
412 debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
413 "ok" : "not found", host);
414 return host_status;
415}
416
417
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000418/*
419 * Check a given file for security. This is defined as all components
Ben Lindstromd4ee3492002-08-20 18:42:13 +0000420 * of the path to the file must be owned by either the owner of
Ben Lindstrom60567ff2001-06-05 20:27:53 +0000421 * of the file or root and no directories must be group or world writable.
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000422 *
423 * XXX Should any specific check be done for sym links ?
424 *
425 * Takes an open file descriptor, the file name, a uid and and
426 * error buffer plus max size as arguments.
427 *
428 * Returns 0 on success and -1 on failure
429 */
Darren Tucker33c787f2008-07-02 22:37:30 +1000430static int
Ben Lindstrom248c0782001-07-04 03:40:39 +0000431secure_filename(FILE *f, const char *file, struct passwd *pw,
432 char *err, size_t errlen)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000433{
Ben Lindstrom248c0782001-07-04 03:40:39 +0000434 uid_t uid = pw->pw_uid;
Ben Lindstromc3e49e72001-10-03 17:55:26 +0000435 char buf[MAXPATHLEN], homedir[MAXPATHLEN];
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000436 char *cp;
Ben Lindstrom485075e2002-11-09 15:45:12 +0000437 int comparehome = 0;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000438 struct stat st;
439
440 if (realpath(file, buf) == NULL) {
441 snprintf(err, errlen, "realpath %s failed: %s", file,
442 strerror(errno));
443 return -1;
444 }
Ben Lindstrom485075e2002-11-09 15:45:12 +0000445 if (realpath(pw->pw_dir, homedir) != NULL)
446 comparehome = 1;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000447
448 /* check the open file to avoid races */
449 if (fstat(fileno(f), &st) < 0 ||
450 (st.st_uid != 0 && st.st_uid != uid) ||
451 (st.st_mode & 022) != 0) {
452 snprintf(err, errlen, "bad ownership or modes for file %s",
453 buf);
454 return -1;
455 }
456
457 /* for each component of the canonical path, walking upwards */
458 for (;;) {
459 if ((cp = dirname(buf)) == NULL) {
460 snprintf(err, errlen, "dirname() failed");
461 return -1;
462 }
463 strlcpy(buf, cp, sizeof(buf));
464
465 debug3("secure_filename: checking '%s'", buf);
466 if (stat(buf, &st) < 0 ||
467 (st.st_uid != 0 && st.st_uid != uid) ||
468 (st.st_mode & 022) != 0) {
Damien Miller9f0f5c62001-12-21 14:45:46 +1100469 snprintf(err, errlen,
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000470 "bad ownership or modes for directory %s", buf);
471 return -1;
472 }
473
Darren Tuckere2b36742010-01-13 22:42:34 +1100474 /* If are past the homedir then we can stop */
Ben Lindstrom485075e2002-11-09 15:45:12 +0000475 if (comparehome && strcmp(homedir, buf) == 0) {
Damien Miller0ae6e002001-07-14 12:21:34 +1000476 debug3("secure_filename: terminating check at '%s'",
477 buf);
478 break;
479 }
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000480 /*
481 * dirname should always complete with a "/" path,
482 * but we can be paranoid and check for "." too
483 */
484 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
485 break;
486 }
487 return 0;
488}
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000489
Damien Miller30da3442010-05-10 11:58:03 +1000490static FILE *
491auth_openfile(const char *file, struct passwd *pw, int strict_modes,
492 int log_missing, char *file_type)
Darren Tucker33c787f2008-07-02 22:37:30 +1000493{
494 char line[1024];
495 struct stat st;
496 int fd;
497 FILE *f;
498
Darren Tucker43551522010-01-10 19:27:17 +1100499 if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
Damien Miller30da3442010-05-10 11:58:03 +1000500 if (log_missing || errno != ENOENT)
501 debug("Could not open %s '%s': %s", file_type, file,
Darren Tucker43551522010-01-10 19:27:17 +1100502 strerror(errno));
Darren Tucker33c787f2008-07-02 22:37:30 +1000503 return NULL;
Darren Tucker43551522010-01-10 19:27:17 +1100504 }
Darren Tucker33c787f2008-07-02 22:37:30 +1000505
506 if (fstat(fd, &st) < 0) {
507 close(fd);
508 return NULL;
509 }
510 if (!S_ISREG(st.st_mode)) {
Damien Miller30da3442010-05-10 11:58:03 +1000511 logit("User %s %s %s is not a regular file",
512 pw->pw_name, file_type, file);
Darren Tucker33c787f2008-07-02 22:37:30 +1000513 close(fd);
514 return NULL;
515 }
516 unset_nonblock(fd);
517 if ((f = fdopen(fd, "r")) == NULL) {
518 close(fd);
519 return NULL;
520 }
521 if (options.strict_modes &&
522 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
523 fclose(f);
524 logit("Authentication refused: %s", line);
Damien Miller48147d62010-06-26 09:39:25 +1000525 auth_debug_add("Ignored %s: %s", file_type, line);
Darren Tucker33c787f2008-07-02 22:37:30 +1000526 return NULL;
527 }
528
529 return f;
530}
531
Damien Miller30da3442010-05-10 11:58:03 +1000532
533FILE *
534auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
535{
536 return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
537}
538
539FILE *
540auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
541{
542 return auth_openfile(file, pw, strict_modes, 0,
543 "authorized principals");
544}
545
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000546struct passwd *
547getpwnamallow(const char *user)
548{
Ben Lindstromb481e132002-03-22 01:35:47 +0000549#ifdef HAVE_LOGIN_CAP
550 extern login_cap_t *lc;
551#ifdef BSD_AUTH
552 auth_session_t *as;
553#endif
554#endif
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000555 struct passwd *pw;
556
Darren Tucker45150472006-07-12 22:34:17 +1000557 parse_server_match_config(&options, user,
558 get_canonical_hostname(options.use_dns), get_remote_ipaddr());
559
Darren Tuckerb3d20a32010-03-07 11:56:59 +1100560#if defined(_AIX) && defined(HAVE_SETAUTHDB)
561 aix_setauthdb(user);
562#endif
563
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000564 pw = getpwnam(user);
Darren Tuckerb3d20a32010-03-07 11:56:59 +1100565
566#if defined(_AIX) && defined(HAVE_SETAUTHDB)
567 aix_restoreauthdb();
568#endif
Damien Milleracc9b292010-03-01 04:36:54 +1100569#ifdef HAVE_CYGWIN
570 /*
571 * Windows usernames are case-insensitive. To avoid later problems
572 * when trying to match the username, the user is only allowed to
573 * login if the username is given in the same case as stored in the
574 * user database.
575 */
576 if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
577 logit("Login name %.100s does not match stored username %.100s",
578 user, pw->pw_name);
579 pw = NULL;
580 }
581#endif
Damien Miller6f0a1882002-09-22 01:26:51 +1000582 if (pw == NULL) {
Damien Millera22f2d72004-07-21 20:48:24 +1000583 logit("Invalid user %.100s from %.100s",
Damien Miller6f0a1882002-09-22 01:26:51 +1000584 user, get_remote_ipaddr());
Darren Tucker97363a82003-05-02 23:42:25 +1000585#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker42d9dc72005-02-02 17:10:11 +1100586 record_failed_login(user,
587 get_canonical_hostname(options.use_dns), "ssh");
Ben Lindstromf5397c02002-11-09 16:11:10 +0000588#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100589#ifdef SSH_AUDIT_EVENTS
590 audit_event(SSH_INVALID_USER);
591#endif /* SSH_AUDIT_EVENTS */
Damien Miller6f0a1882002-09-22 01:26:51 +1000592 return (NULL);
593 }
594 if (!allowed_user(pw))
Ben Lindstromb481e132002-03-22 01:35:47 +0000595 return (NULL);
596#ifdef HAVE_LOGIN_CAP
597 if ((lc = login_getclass(pw->pw_class)) == NULL) {
598 debug("unable to get login class: %s", user);
599 return (NULL);
600 }
601#ifdef BSD_AUTH
602 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
Damien Miller13e35a02002-05-22 14:04:11 +1000603 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
Ben Lindstromb481e132002-03-22 01:35:47 +0000604 debug("Approval failure for %s", user);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000605 pw = NULL;
Ben Lindstromb481e132002-03-22 01:35:47 +0000606 }
607 if (as != NULL)
608 auth_close(as);
609#endif
610#endif
Ben Lindstromf34e4eb2002-03-22 03:08:30 +0000611 if (pw != NULL)
612 return (pwcopy(pw));
613 return (NULL);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000614}
Ben Lindstroma574cda2002-05-15 16:16:14 +0000615
Damien Miller1aed65e2010-03-04 21:53:35 +1100616/* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
617int
618auth_key_is_revoked(Key *key)
619{
620 char *key_fp;
621
622 if (options.revoked_keys_file == NULL)
623 return 0;
624
625 switch (key_in_file(key, options.revoked_keys_file, 0)) {
626 case 0:
627 /* key not revoked */
628 return 0;
629 case -1:
630 /* Error opening revoked_keys_file: refuse all keys */
631 error("Revoked keys file is unreadable: refusing public key "
632 "authentication");
633 return 1;
634 case 1:
635 /* Key revoked */
636 key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
Damien Millerb068d0a2010-03-05 14:03:03 +1100637 error("WARNING: authentication attempt with a revoked "
638 "%s key %s ", key_type(key), key_fp);
Damien Miller1aed65e2010-03-04 21:53:35 +1100639 xfree(key_fp);
640 return 1;
641 }
642 fatal("key_in_file returned junk");
643}
644
Ben Lindstroma574cda2002-05-15 16:16:14 +0000645void
646auth_debug_add(const char *fmt,...)
647{
648 char buf[1024];
649 va_list args;
650
651 if (!auth_debug_init)
652 return;
653
654 va_start(args, fmt);
655 vsnprintf(buf, sizeof(buf), fmt, args);
656 va_end(args);
657 buffer_put_cstring(&auth_debug, buf);
658}
659
660void
661auth_debug_send(void)
662{
663 char *msg;
664
665 if (!auth_debug_init)
666 return;
667 while (buffer_len(&auth_debug)) {
668 msg = buffer_get_string(&auth_debug, NULL);
669 packet_send_debug("%s", msg);
670 xfree(msg);
671 }
672}
673
674void
675auth_debug_reset(void)
676{
677 if (auth_debug_init)
678 buffer_clear(&auth_debug);
679 else {
680 buffer_init(&auth_debug);
681 auth_debug_init = 1;
682 }
683}
Damien Miller856f0be2003-09-03 07:32:45 +1000684
685struct passwd *
686fakepw(void)
687{
688 static struct passwd fake;
689
690 memset(&fake, 0, sizeof(fake));
691 fake.pw_name = "NOUSER";
692 fake.pw_passwd =
Damien Miller787b2ec2003-11-21 23:56:47 +1100693 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
Damien Miller856f0be2003-09-03 07:32:45 +1000694 fake.pw_gecos = "NOUSER";
Damien Miller143c2ef2006-12-05 09:08:54 +1100695 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
696 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
Damien Miller856f0be2003-09-03 07:32:45 +1000697#ifdef HAVE_PW_CLASS_IN_PASSWD
698 fake.pw_class = "";
699#endif
700 fake.pw_dir = "/nonexist";
701 fake.pw_shell = "/nonexist";
702
703 return (&fake);
704}