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Damien Miller6f66d342008-11-05 16:12:54 +11001/* $OpenBSD: auth.c,v 1.80 2008/11/04 07:58:09 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
Darren Tucker269a1ea2005-02-03 00:20:53 +110072#include "monitor_wrap.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100073
Damien Millerb38eff82000-04-01 11:09:21 +100074/* import */
75extern ServerOptions options;
Damien Miller7a8f5b32006-03-31 23:14:23 +110076extern int use_privsep;
Darren Tuckerb9aa0a02003-07-08 22:59:59 +100077extern Buffer loginmsg;
Damien Miller6433df02006-09-07 10:36:43 +100078extern struct passwd *privsep_pw;
Damien Millerb38eff82000-04-01 11:09:21 +100079
Ben Lindstroma574cda2002-05-15 16:16:14 +000080/* Debugging messages */
81Buffer auth_debug;
82int auth_debug_init;
83
Damien Millerb38eff82000-04-01 11:09:21 +100084/*
Kevin Steves7b61cfa2001-01-14 19:11:00 +000085 * Check if the user is allowed to log in via ssh. If user is listed
86 * in DenyUsers or one of user's groups is listed in DenyGroups, false
87 * will be returned. If AllowUsers isn't empty and user isn't listed
88 * there, or if AllowGroups isn't empty and one of user's groups isn't
89 * listed there, false will be returned.
Damien Millerb38eff82000-04-01 11:09:21 +100090 * If the user's shell is not executable, false will be returned.
Damien Miller4af51302000-04-16 11:18:38 +100091 * Otherwise true is returned.
Damien Millerb38eff82000-04-01 11:09:21 +100092 */
Damien Millereba71ba2000-04-29 23:57:08 +100093int
Damien Millerb38eff82000-04-01 11:09:21 +100094allowed_user(struct passwd * pw)
95{
96 struct stat st;
Darren Tucker43a0dc62003-08-26 14:22:12 +100097 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
Damien Millere7cf07c2001-03-20 09:15:57 +110098 char *shell;
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 /*
156 * Get the shell from the password data. An empty shell field is
157 * legal, and means /bin/sh.
158 */
159 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
160
161 /* deny if shell does not exists or is not executable */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000162 if (stat(shell, &st) != 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000163 logit("User %.100s not allowed because shell %.100s does not exist",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000164 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000165 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000166 }
Ben Lindstromb61e6df2002-03-22 01:15:33 +0000167 if (S_ISREG(st.st_mode) == 0 ||
168 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000169 logit("User %.100s not allowed because shell %.100s is not executable",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000170 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000171 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000172 }
Damien Millerb38eff82000-04-01 11:09:21 +1000173
Darren Tuckera8f553d2005-03-14 23:17:27 +1100174 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
175 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Damien Miller3a961dc2003-06-03 10:25:48 +1000176 hostname = get_canonical_hostname(options.use_dns);
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000177 ipaddr = get_remote_ipaddr();
178 }
179
Damien Millerb38eff82000-04-01 11:09:21 +1000180 /* Return false if user is listed in DenyUsers */
181 if (options.num_deny_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000182 for (i = 0; i < options.num_deny_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000183 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000184 options.deny_users[i])) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100185 logit("User %.100s from %.100s not allowed "
186 "because listed in DenyUsers",
187 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000188 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000189 }
Damien Millerb38eff82000-04-01 11:09:21 +1000190 }
191 /* Return false if AllowUsers isn't empty and user isn't listed there */
192 if (options.num_allow_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000193 for (i = 0; i < options.num_allow_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000194 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom60260022001-07-04 04:56:44 +0000195 options.allow_users[i]))
Damien Millerb38eff82000-04-01 11:09:21 +1000196 break;
197 /* i < options.num_allow_users iff we break for loop */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000198 if (i >= options.num_allow_users) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100199 logit("User %.100s from %.100s not allowed because "
200 "not listed in AllowUsers", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000201 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000202 }
Damien Millerb38eff82000-04-01 11:09:21 +1000203 }
Damien Millerb38eff82000-04-01 11:09:21 +1000204 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000205 /* Get the user's group access list (primary and supplementary) */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000206 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100207 logit("User %.100s from %.100s not allowed because "
208 "not in any group", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000209 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000210 }
Damien Millerb38eff82000-04-01 11:09:21 +1000211
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000212 /* Return false if one of user's groups is listed in DenyGroups */
213 if (options.num_deny_groups > 0)
214 if (ga_match(options.deny_groups,
215 options.num_deny_groups)) {
216 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100217 logit("User %.100s from %.100s not allowed "
218 "because a group is listed in DenyGroups",
219 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000220 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000221 }
Damien Millerb38eff82000-04-01 11:09:21 +1000222 /*
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000223 * Return false if AllowGroups isn't empty and one of user's groups
Damien Millerb38eff82000-04-01 11:09:21 +1000224 * isn't listed there
225 */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000226 if (options.num_allow_groups > 0)
227 if (!ga_match(options.allow_groups,
228 options.num_allow_groups)) {
229 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100230 logit("User %.100s from %.100s not allowed "
231 "because none of user's groups are listed "
232 "in AllowGroups", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000233 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000234 }
235 ga_free();
Damien Millerb38eff82000-04-01 11:09:21 +1000236 }
237
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000238#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
Darren Tucker691d5232005-02-15 21:45:57 +1100239 if (!sys_auth_allowed_user(pw, &loginmsg))
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000240 return 0;
241#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000242
243 /* We found no reason not to let this user try to log on... */
244 return 1;
245}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000246
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000247void
248auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
249{
250 void (*authlog) (const char *fmt,...) = verbose;
251 char *authmsg;
252
Damien Miller7a8f5b32006-03-31 23:14:23 +1100253 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
254 return;
255
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000256 /* Raise logging level */
257 if (authenticated == 1 ||
258 !authctxt->valid ||
Darren Tucker89413db2004-05-24 10:36:23 +1000259 authctxt->failures >= options.max_authtries / 2 ||
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000260 strcmp(method, "password") == 0)
Damien Miller2a3f20e2003-04-09 21:12:00 +1000261 authlog = logit;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000262
263 if (authctxt->postponed)
264 authmsg = "Postponed";
265 else
266 authmsg = authenticated ? "Accepted" : "Failed";
267
268 authlog("%s %s for %s%.100s from %.200s port %d%s",
269 authmsg,
270 method,
Darren Tucker5cb30ad2004-08-12 22:40:24 +1000271 authctxt->valid ? "" : "invalid user ",
Damien Millerf6552072001-11-12 11:06:06 +1100272 authctxt->user,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000273 get_remote_ipaddr(),
274 get_remote_port(),
275 info);
Ben Lindstrome06eb682002-07-04 00:27:21 +0000276
Darren Tucker97363a82003-05-02 23:42:25 +1000277#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker2fba9932005-02-02 23:30:24 +1100278 if (authenticated == 0 && !authctxt->postponed &&
279 (strcmp(method, "password") == 0 ||
Darren Tucker40d9a632005-02-04 15:19:44 +1100280 strncmp(method, "keyboard-interactive", 20) == 0 ||
281 strcmp(method, "challenge-response") == 0))
Darren Tucker42d9dc72005-02-02 17:10:11 +1100282 record_failed_login(authctxt->user,
283 get_canonical_hostname(options.use_dns), "ssh");
Darren Tucker26d4e192006-08-30 22:33:09 +1000284# ifdef WITH_AIXAUTHENTICATE
285 if (authenticated)
286 sys_auth_record_login(authctxt->user,
287 get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
288# endif
Darren Tucker97363a82003-05-02 23:42:25 +1000289#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100290#ifdef SSH_AUDIT_EVENTS
Darren Tuckerf14b2aa2006-05-21 18:26:40 +1000291 if (authenticated == 0 && !authctxt->postponed)
292 audit_event(audit_classify_auth(method));
Darren Tucker269a1ea2005-02-03 00:20:53 +1100293#endif
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000294}
295
296/*
Ben Lindstromd8a90212001-02-15 03:08:27 +0000297 * Check whether root logins are disallowed.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000298 */
299int
Ben Lindstromd8a90212001-02-15 03:08:27 +0000300auth_root_allowed(char *method)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000301{
Ben Lindstromd8a90212001-02-15 03:08:27 +0000302 switch (options.permit_root_login) {
303 case PERMIT_YES:
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000304 return 1;
Ben Lindstromd8a90212001-02-15 03:08:27 +0000305 case PERMIT_NO_PASSWD:
306 if (strcmp(method, "password") != 0)
307 return 1;
308 break;
309 case PERMIT_FORCED_ONLY:
310 if (forced_command) {
Damien Miller996acd22003-04-09 20:59:48 +1000311 logit("Root login accepted for forced command.");
Ben Lindstromd8a90212001-02-15 03:08:27 +0000312 return 1;
313 }
314 break;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000315 }
Damien Miller996acd22003-04-09 20:59:48 +1000316 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
Ben Lindstromd8a90212001-02-15 03:08:27 +0000317 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000318}
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000319
320
321/*
322 * Given a template and a passwd structure, build a filename
323 * by substituting % tokenised options. Currently, %% becomes '%',
324 * %h becomes the home directory and %u the username.
325 *
326 * This returns a buffer allocated by xmalloc.
327 */
Damien Miller6476cad2005-06-16 13:18:34 +1000328static char *
329expand_authorized_keys(const char *filename, struct passwd *pw)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000330{
Damien Miller07d86be2006-03-26 14:19:21 +1100331 char *file, ret[MAXPATHLEN];
332 int i;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000333
Damien Miller6476cad2005-06-16 13:18:34 +1000334 file = percent_expand(filename, "h", pw->pw_dir,
335 "u", pw->pw_name, (char *)NULL);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000336
337 /*
338 * Ensure that filename starts anchored. If not, be backward
339 * compatible and prepend the '%h/'
340 */
Damien Miller6476cad2005-06-16 13:18:34 +1000341 if (*file == '/')
342 return (file);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000343
Damien Miller07d86be2006-03-26 14:19:21 +1100344 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
345 if (i < 0 || (size_t)i >= sizeof(ret))
Damien Miller6476cad2005-06-16 13:18:34 +1000346 fatal("expand_authorized_keys: path too long");
Damien Miller6476cad2005-06-16 13:18:34 +1000347 xfree(file);
Damien Miller07d86be2006-03-26 14:19:21 +1100348 return (xstrdup(ret));
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000349}
350
351char *
352authorized_keys_file(struct passwd *pw)
353{
Damien Miller6476cad2005-06-16 13:18:34 +1000354 return expand_authorized_keys(options.authorized_keys_file, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000355}
356
357char *
358authorized_keys_file2(struct passwd *pw)
359{
Damien Miller6476cad2005-06-16 13:18:34 +1000360 return expand_authorized_keys(options.authorized_keys_file2, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000361}
362
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000363/* return ok if key exists in sysfile or userfile */
364HostStatus
365check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
366 const char *sysfile, const char *userfile)
367{
368 Key *found;
369 char *user_hostfile;
370 struct stat st;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000371 HostStatus host_status;
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000372
373 /* Check if we know the host and its host key. */
374 found = key_new(key->type);
375 host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
376
377 if (host_status != HOST_OK && userfile != NULL) {
378 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
379 if (options.strict_modes &&
380 (stat(user_hostfile, &st) == 0) &&
381 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
Damien Miller9f0f5c62001-12-21 14:45:46 +1100382 (st.st_mode & 022) != 0)) {
Damien Miller996acd22003-04-09 20:59:48 +1000383 logit("Authentication refused for %.100s: "
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000384 "bad owner or modes for %.200s",
385 pw->pw_name, user_hostfile);
386 } else {
387 temporarily_use_uid(pw);
388 host_status = check_host_in_hostfile(user_hostfile,
389 host, key, found, NULL);
390 restore_uid();
391 }
392 xfree(user_hostfile);
393 }
394 key_free(found);
395
396 debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
397 "ok" : "not found", host);
398 return host_status;
399}
400
401
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000402/*
403 * Check a given file for security. This is defined as all components
Ben Lindstromd4ee3492002-08-20 18:42:13 +0000404 * of the path to the file must be owned by either the owner of
Ben Lindstrom60567ff2001-06-05 20:27:53 +0000405 * of the file or root and no directories must be group or world writable.
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000406 *
407 * XXX Should any specific check be done for sym links ?
408 *
409 * Takes an open file descriptor, the file name, a uid and and
410 * error buffer plus max size as arguments.
411 *
412 * Returns 0 on success and -1 on failure
413 */
Darren Tucker33c787f2008-07-02 22:37:30 +1000414static int
Ben Lindstrom248c0782001-07-04 03:40:39 +0000415secure_filename(FILE *f, const char *file, struct passwd *pw,
416 char *err, size_t errlen)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000417{
Ben Lindstrom248c0782001-07-04 03:40:39 +0000418 uid_t uid = pw->pw_uid;
Ben Lindstromc3e49e72001-10-03 17:55:26 +0000419 char buf[MAXPATHLEN], homedir[MAXPATHLEN];
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000420 char *cp;
Ben Lindstrom485075e2002-11-09 15:45:12 +0000421 int comparehome = 0;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000422 struct stat st;
423
424 if (realpath(file, buf) == NULL) {
425 snprintf(err, errlen, "realpath %s failed: %s", file,
426 strerror(errno));
427 return -1;
428 }
Ben Lindstrom485075e2002-11-09 15:45:12 +0000429 if (realpath(pw->pw_dir, homedir) != NULL)
430 comparehome = 1;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000431
432 /* check the open file to avoid races */
433 if (fstat(fileno(f), &st) < 0 ||
434 (st.st_uid != 0 && st.st_uid != uid) ||
435 (st.st_mode & 022) != 0) {
436 snprintf(err, errlen, "bad ownership or modes for file %s",
437 buf);
438 return -1;
439 }
440
441 /* for each component of the canonical path, walking upwards */
442 for (;;) {
443 if ((cp = dirname(buf)) == NULL) {
444 snprintf(err, errlen, "dirname() failed");
445 return -1;
446 }
447 strlcpy(buf, cp, sizeof(buf));
448
449 debug3("secure_filename: checking '%s'", buf);
450 if (stat(buf, &st) < 0 ||
451 (st.st_uid != 0 && st.st_uid != uid) ||
452 (st.st_mode & 022) != 0) {
Damien Miller9f0f5c62001-12-21 14:45:46 +1100453 snprintf(err, errlen,
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000454 "bad ownership or modes for directory %s", buf);
455 return -1;
456 }
457
Damien Miller0ae6e002001-07-14 12:21:34 +1000458 /* If are passed the homedir then we can stop */
Ben Lindstrom485075e2002-11-09 15:45:12 +0000459 if (comparehome && strcmp(homedir, buf) == 0) {
Damien Miller0ae6e002001-07-14 12:21:34 +1000460 debug3("secure_filename: terminating check at '%s'",
461 buf);
462 break;
463 }
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000464 /*
465 * dirname should always complete with a "/" path,
466 * but we can be paranoid and check for "." too
467 */
468 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
469 break;
470 }
471 return 0;
472}
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000473
Darren Tucker33c787f2008-07-02 22:37:30 +1000474FILE *
475auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
476{
477 char line[1024];
478 struct stat st;
479 int fd;
480 FILE *f;
481
482 /*
483 * Open the file containing the authorized keys
484 * Fail quietly if file does not exist
485 */
486 if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1)
487 return NULL;
488
489 if (fstat(fd, &st) < 0) {
490 close(fd);
491 return NULL;
492 }
493 if (!S_ISREG(st.st_mode)) {
494 logit("User %s authorized keys %s is not a regular file",
495 pw->pw_name, file);
496 close(fd);
497 return NULL;
498 }
499 unset_nonblock(fd);
500 if ((f = fdopen(fd, "r")) == NULL) {
501 close(fd);
502 return NULL;
503 }
504 if (options.strict_modes &&
505 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
506 fclose(f);
507 logit("Authentication refused: %s", line);
508 return NULL;
509 }
510
511 return f;
512}
513
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000514struct passwd *
515getpwnamallow(const char *user)
516{
Ben Lindstromb481e132002-03-22 01:35:47 +0000517#ifdef HAVE_LOGIN_CAP
518 extern login_cap_t *lc;
519#ifdef BSD_AUTH
520 auth_session_t *as;
521#endif
522#endif
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000523 struct passwd *pw;
524
Darren Tucker45150472006-07-12 22:34:17 +1000525 parse_server_match_config(&options, user,
526 get_canonical_hostname(options.use_dns), get_remote_ipaddr());
527
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000528 pw = getpwnam(user);
Damien Miller6f0a1882002-09-22 01:26:51 +1000529 if (pw == NULL) {
Damien Millera22f2d72004-07-21 20:48:24 +1000530 logit("Invalid user %.100s from %.100s",
Damien Miller6f0a1882002-09-22 01:26:51 +1000531 user, get_remote_ipaddr());
Darren Tucker97363a82003-05-02 23:42:25 +1000532#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker42d9dc72005-02-02 17:10:11 +1100533 record_failed_login(user,
534 get_canonical_hostname(options.use_dns), "ssh");
Ben Lindstromf5397c02002-11-09 16:11:10 +0000535#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100536#ifdef SSH_AUDIT_EVENTS
537 audit_event(SSH_INVALID_USER);
538#endif /* SSH_AUDIT_EVENTS */
Damien Miller6f0a1882002-09-22 01:26:51 +1000539 return (NULL);
540 }
541 if (!allowed_user(pw))
Ben Lindstromb481e132002-03-22 01:35:47 +0000542 return (NULL);
543#ifdef HAVE_LOGIN_CAP
544 if ((lc = login_getclass(pw->pw_class)) == NULL) {
545 debug("unable to get login class: %s", user);
546 return (NULL);
547 }
548#ifdef BSD_AUTH
549 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
Damien Miller13e35a02002-05-22 14:04:11 +1000550 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
Ben Lindstromb481e132002-03-22 01:35:47 +0000551 debug("Approval failure for %s", user);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000552 pw = NULL;
Ben Lindstromb481e132002-03-22 01:35:47 +0000553 }
554 if (as != NULL)
555 auth_close(as);
556#endif
557#endif
Ben Lindstromf34e4eb2002-03-22 03:08:30 +0000558 if (pw != NULL)
559 return (pwcopy(pw));
560 return (NULL);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000561}
Ben Lindstroma574cda2002-05-15 16:16:14 +0000562
563void
564auth_debug_add(const char *fmt,...)
565{
566 char buf[1024];
567 va_list args;
568
569 if (!auth_debug_init)
570 return;
571
572 va_start(args, fmt);
573 vsnprintf(buf, sizeof(buf), fmt, args);
574 va_end(args);
575 buffer_put_cstring(&auth_debug, buf);
576}
577
578void
579auth_debug_send(void)
580{
581 char *msg;
582
583 if (!auth_debug_init)
584 return;
585 while (buffer_len(&auth_debug)) {
586 msg = buffer_get_string(&auth_debug, NULL);
587 packet_send_debug("%s", msg);
588 xfree(msg);
589 }
590}
591
592void
593auth_debug_reset(void)
594{
595 if (auth_debug_init)
596 buffer_clear(&auth_debug);
597 else {
598 buffer_init(&auth_debug);
599 auth_debug_init = 1;
600 }
601}
Damien Miller856f0be2003-09-03 07:32:45 +1000602
603struct passwd *
604fakepw(void)
605{
606 static struct passwd fake;
607
608 memset(&fake, 0, sizeof(fake));
609 fake.pw_name = "NOUSER";
610 fake.pw_passwd =
Damien Miller787b2ec2003-11-21 23:56:47 +1100611 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
Damien Miller856f0be2003-09-03 07:32:45 +1000612 fake.pw_gecos = "NOUSER";
Damien Miller143c2ef2006-12-05 09:08:54 +1100613 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
614 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
Damien Miller856f0be2003-09-03 07:32:45 +1000615#ifdef HAVE_PW_CLASS_IN_PASSWD
616 fake.pw_class = "";
617#endif
618 fake.pw_dir = "/nonexist";
619 fake.pw_shell = "/nonexist";
620
621 return (&fake);
622}