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Damien Miller8dbffe72006-08-05 11:02:17 +10001/* $OpenBSD: auth.c,v 1.73 2006/07/26 02:35:17 stevesk 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
Darren Tucker39972492006-07-12 22:22:46 +100032#include <errno.h>
Damien Miller03e20032006-03-15 11:16:59 +110033#ifdef HAVE_PATHS_H
Damien Millera9263d02006-03-15 11:18:26 +110034# include <paths.h>
Damien Miller03e20032006-03-15 11:16:59 +110035#endif
Damien Miller9f2abc42006-07-10 20:53:08 +100036#include <pwd.h>
Damien Millerd2c208a2000-05-17 22:00:02 +100037#ifdef HAVE_LOGIN_H
38#include <login.h>
39#endif
Darren Tucker15ee7482004-02-22 09:43:15 +110040#ifdef USE_SHADOW
Damien Miller1f335fb2000-06-26 11:31:33 +100041#include <shadow.h>
Darren Tucker15ee7482004-02-22 09:43:15 +110042#endif
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000043#ifdef HAVE_LIBGEN_H
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000044#include <libgen.h>
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000045#endif
Darren Tucker5d196262006-07-12 22:15:16 +100046#include <stdarg.h>
Damien Millere3476ed2006-07-24 14:13:33 +100047#include <string.h>
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000048
Ben Lindstrom226cfa02001-01-22 05:34:40 +000049#include "xmalloc.h"
50#include "match.h"
51#include "groupaccess.h"
52#include "log.h"
53#include "servconf.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100054#include "auth.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000055#include "auth-options.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000056#include "canohost.h"
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000057#include "buffer.h"
58#include "bufaux.h"
Ben Lindstrom83647ce2001-06-25 04:30:16 +000059#include "uidswap.h"
Ben Lindstrom7ebb6352002-03-22 03:04:08 +000060#include "misc.h"
Ben Lindstroma574cda2002-05-15 16:16:14 +000061#include "bufaux.h"
62#include "packet.h"
Darren Tucker42d9dc72005-02-02 17:10:11 +110063#include "loginrec.h"
Darren Tucker269a1ea2005-02-03 00:20:53 +110064#include "monitor_wrap.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100065
Damien Millerb38eff82000-04-01 11:09:21 +100066/* import */
67extern ServerOptions options;
Damien Miller7a8f5b32006-03-31 23:14:23 +110068extern int use_privsep;
Darren Tuckerb9aa0a02003-07-08 22:59:59 +100069extern Buffer loginmsg;
Damien Millerb38eff82000-04-01 11:09:21 +100070
Ben Lindstroma574cda2002-05-15 16:16:14 +000071/* Debugging messages */
72Buffer auth_debug;
73int auth_debug_init;
74
Damien Millerb38eff82000-04-01 11:09:21 +100075/*
Kevin Steves7b61cfa2001-01-14 19:11:00 +000076 * Check if the user is allowed to log in via ssh. If user is listed
77 * in DenyUsers or one of user's groups is listed in DenyGroups, false
78 * will be returned. If AllowUsers isn't empty and user isn't listed
79 * there, or if AllowGroups isn't empty and one of user's groups isn't
80 * listed there, false will be returned.
Damien Millerb38eff82000-04-01 11:09:21 +100081 * If the user's shell is not executable, false will be returned.
Damien Miller4af51302000-04-16 11:18:38 +100082 * Otherwise true is returned.
Damien Millerb38eff82000-04-01 11:09:21 +100083 */
Damien Millereba71ba2000-04-29 23:57:08 +100084int
Damien Millerb38eff82000-04-01 11:09:21 +100085allowed_user(struct passwd * pw)
86{
87 struct stat st;
Darren Tucker43a0dc62003-08-26 14:22:12 +100088 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
Damien Millere7cf07c2001-03-20 09:15:57 +110089 char *shell;
Damien Millereccb9de2005-06-17 12:59:34 +100090 u_int i;
Darren Tucker15ee7482004-02-22 09:43:15 +110091#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +100092 struct spwd *spw = NULL;
Tim Rice458c6bf2003-01-08 20:04:27 -080093#endif
Damien Millerb38eff82000-04-01 11:09:21 +100094
95 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
Kevin Steves7b61cfa2001-01-14 19:11:00 +000096 if (!pw || !pw->pw_name)
Damien Millerb38eff82000-04-01 11:09:21 +100097 return 0;
98
Darren Tucker15ee7482004-02-22 09:43:15 +110099#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000100 if (!options.use_pam)
101 spw = getspnam(pw->pw_name);
102#ifdef HAS_SHADOW_EXPIRE
Darren Tucker15ee7482004-02-22 09:43:15 +1100103 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
104 return 0;
Darren Tuckere41bba52003-08-25 11:51:19 +1000105#endif /* HAS_SHADOW_EXPIRE */
Darren Tucker15ee7482004-02-22 09:43:15 +1100106#endif /* USE_SHADOW */
Darren Tuckere41bba52003-08-25 11:51:19 +1000107
Damien Millera8e06ce2003-11-21 23:48:55 +1100108 /* grab passwd field for locked account check */
Darren Tucker15ee7482004-02-22 09:43:15 +1100109#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000110 if (spw != NULL)
Tim Rice66fd2172005-08-31 09:59:49 -0700111#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
Tim Rice2291c002005-08-26 13:15:19 -0700112 passwd = get_iaf_password(pw);
113#else
Darren Tuckere41bba52003-08-25 11:51:19 +1000114 passwd = spw->sp_pwdp;
Tim Rice66fd2172005-08-31 09:59:49 -0700115#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000116#else
117 passwd = pw->pw_passwd;
Damien Miller06817f92003-01-07 23:55:59 +1100118#endif
119
Damien Millera8e06ce2003-11-21 23:48:55 +1100120 /* check for locked account */
Darren Tucker43a0dc62003-08-26 14:22:12 +1000121 if (!options.use_pam && passwd && *passwd) {
Darren Tuckere41bba52003-08-25 11:51:19 +1000122 int locked = 0;
123
124#ifdef LOCKED_PASSWD_STRING
125 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
126 locked = 1;
127#endif
128#ifdef LOCKED_PASSWD_PREFIX
129 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
130 strlen(LOCKED_PASSWD_PREFIX)) == 0)
131 locked = 1;
132#endif
133#ifdef LOCKED_PASSWD_SUBSTR
134 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
135 locked = 1;
136#endif
Tim Rice66fd2172005-08-31 09:59:49 -0700137#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
138 free(passwd);
139#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000140 if (locked) {
141 logit("User %.100s not allowed because account is locked",
142 pw->pw_name);
143 return 0;
144 }
145 }
146
Damien Milleref7df542000-05-19 00:03:23 +1000147 /*
148 * Get the shell from the password data. An empty shell field is
149 * legal, and means /bin/sh.
150 */
151 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
152
153 /* deny if shell does not exists or is not executable */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000154 if (stat(shell, &st) != 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000155 logit("User %.100s not allowed because shell %.100s does not exist",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000156 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000157 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000158 }
Ben Lindstromb61e6df2002-03-22 01:15:33 +0000159 if (S_ISREG(st.st_mode) == 0 ||
160 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000161 logit("User %.100s not allowed because shell %.100s is not executable",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000162 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000163 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000164 }
Damien Millerb38eff82000-04-01 11:09:21 +1000165
Darren Tuckera8f553d2005-03-14 23:17:27 +1100166 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
167 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Damien Miller3a961dc2003-06-03 10:25:48 +1000168 hostname = get_canonical_hostname(options.use_dns);
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000169 ipaddr = get_remote_ipaddr();
170 }
171
Damien Millerb38eff82000-04-01 11:09:21 +1000172 /* Return false if user is listed in DenyUsers */
173 if (options.num_deny_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000174 for (i = 0; i < options.num_deny_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000175 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000176 options.deny_users[i])) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100177 logit("User %.100s from %.100s not allowed "
178 "because listed in DenyUsers",
179 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000180 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000181 }
Damien Millerb38eff82000-04-01 11:09:21 +1000182 }
183 /* Return false if AllowUsers isn't empty and user isn't listed there */
184 if (options.num_allow_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000185 for (i = 0; i < options.num_allow_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000186 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom60260022001-07-04 04:56:44 +0000187 options.allow_users[i]))
Damien Millerb38eff82000-04-01 11:09:21 +1000188 break;
189 /* i < options.num_allow_users iff we break for loop */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000190 if (i >= options.num_allow_users) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100191 logit("User %.100s from %.100s not allowed because "
192 "not listed in AllowUsers", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000193 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000194 }
Damien Millerb38eff82000-04-01 11:09:21 +1000195 }
Damien Millerb38eff82000-04-01 11:09:21 +1000196 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000197 /* Get the user's group access list (primary and supplementary) */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000198 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100199 logit("User %.100s from %.100s not allowed because "
200 "not in any group", 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
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000204 /* Return false if one of user's groups is listed in DenyGroups */
205 if (options.num_deny_groups > 0)
206 if (ga_match(options.deny_groups,
207 options.num_deny_groups)) {
208 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100209 logit("User %.100s from %.100s not allowed "
210 "because a group is listed in DenyGroups",
211 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000212 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000213 }
Damien Millerb38eff82000-04-01 11:09:21 +1000214 /*
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000215 * Return false if AllowGroups isn't empty and one of user's groups
Damien Millerb38eff82000-04-01 11:09:21 +1000216 * isn't listed there
217 */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000218 if (options.num_allow_groups > 0)
219 if (!ga_match(options.allow_groups,
220 options.num_allow_groups)) {
221 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100222 logit("User %.100s from %.100s not allowed "
223 "because none of user's groups are listed "
224 "in AllowGroups", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000225 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000226 }
227 ga_free();
Damien Millerb38eff82000-04-01 11:09:21 +1000228 }
229
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000230#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
Darren Tucker691d5232005-02-15 21:45:57 +1100231 if (!sys_auth_allowed_user(pw, &loginmsg))
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000232 return 0;
233#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000234
235 /* We found no reason not to let this user try to log on... */
236 return 1;
237}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000238
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000239void
240auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
241{
242 void (*authlog) (const char *fmt,...) = verbose;
243 char *authmsg;
244
Damien Miller7a8f5b32006-03-31 23:14:23 +1100245 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
246 return;
247
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000248 /* Raise logging level */
249 if (authenticated == 1 ||
250 !authctxt->valid ||
Darren Tucker89413db2004-05-24 10:36:23 +1000251 authctxt->failures >= options.max_authtries / 2 ||
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000252 strcmp(method, "password") == 0)
Damien Miller2a3f20e2003-04-09 21:12:00 +1000253 authlog = logit;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000254
255 if (authctxt->postponed)
256 authmsg = "Postponed";
257 else
258 authmsg = authenticated ? "Accepted" : "Failed";
259
260 authlog("%s %s for %s%.100s from %.200s port %d%s",
261 authmsg,
262 method,
Darren Tucker5cb30ad2004-08-12 22:40:24 +1000263 authctxt->valid ? "" : "invalid user ",
Damien Millerf6552072001-11-12 11:06:06 +1100264 authctxt->user,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000265 get_remote_ipaddr(),
266 get_remote_port(),
267 info);
Ben Lindstrome06eb682002-07-04 00:27:21 +0000268
Darren Tucker97363a82003-05-02 23:42:25 +1000269#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker2fba9932005-02-02 23:30:24 +1100270 if (authenticated == 0 && !authctxt->postponed &&
271 (strcmp(method, "password") == 0 ||
Darren Tucker40d9a632005-02-04 15:19:44 +1100272 strncmp(method, "keyboard-interactive", 20) == 0 ||
273 strcmp(method, "challenge-response") == 0))
Darren Tucker42d9dc72005-02-02 17:10:11 +1100274 record_failed_login(authctxt->user,
275 get_canonical_hostname(options.use_dns), "ssh");
Darren Tucker97363a82003-05-02 23:42:25 +1000276#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100277#ifdef SSH_AUDIT_EVENTS
Darren Tuckerf14b2aa2006-05-21 18:26:40 +1000278 if (authenticated == 0 && !authctxt->postponed)
279 audit_event(audit_classify_auth(method));
Darren Tucker269a1ea2005-02-03 00:20:53 +1100280#endif
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000281}
282
283/*
Ben Lindstromd8a90212001-02-15 03:08:27 +0000284 * Check whether root logins are disallowed.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000285 */
286int
Ben Lindstromd8a90212001-02-15 03:08:27 +0000287auth_root_allowed(char *method)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000288{
Ben Lindstromd8a90212001-02-15 03:08:27 +0000289 switch (options.permit_root_login) {
290 case PERMIT_YES:
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000291 return 1;
Ben Lindstromd8a90212001-02-15 03:08:27 +0000292 case PERMIT_NO_PASSWD:
293 if (strcmp(method, "password") != 0)
294 return 1;
295 break;
296 case PERMIT_FORCED_ONLY:
297 if (forced_command) {
Damien Miller996acd22003-04-09 20:59:48 +1000298 logit("Root login accepted for forced command.");
Ben Lindstromd8a90212001-02-15 03:08:27 +0000299 return 1;
300 }
301 break;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000302 }
Damien Miller996acd22003-04-09 20:59:48 +1000303 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
Ben Lindstromd8a90212001-02-15 03:08:27 +0000304 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000305}
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000306
307
308/*
309 * Given a template and a passwd structure, build a filename
310 * by substituting % tokenised options. Currently, %% becomes '%',
311 * %h becomes the home directory and %u the username.
312 *
313 * This returns a buffer allocated by xmalloc.
314 */
Damien Miller6476cad2005-06-16 13:18:34 +1000315static char *
316expand_authorized_keys(const char *filename, struct passwd *pw)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000317{
Damien Miller07d86be2006-03-26 14:19:21 +1100318 char *file, ret[MAXPATHLEN];
319 int i;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000320
Damien Miller6476cad2005-06-16 13:18:34 +1000321 file = percent_expand(filename, "h", pw->pw_dir,
322 "u", pw->pw_name, (char *)NULL);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000323
324 /*
325 * Ensure that filename starts anchored. If not, be backward
326 * compatible and prepend the '%h/'
327 */
Damien Miller6476cad2005-06-16 13:18:34 +1000328 if (*file == '/')
329 return (file);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000330
Damien Miller07d86be2006-03-26 14:19:21 +1100331 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
332 if (i < 0 || (size_t)i >= sizeof(ret))
Damien Miller6476cad2005-06-16 13:18:34 +1000333 fatal("expand_authorized_keys: path too long");
Damien Miller6476cad2005-06-16 13:18:34 +1000334 xfree(file);
Damien Miller07d86be2006-03-26 14:19:21 +1100335 return (xstrdup(ret));
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000336}
337
338char *
339authorized_keys_file(struct passwd *pw)
340{
Damien Miller6476cad2005-06-16 13:18:34 +1000341 return expand_authorized_keys(options.authorized_keys_file, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000342}
343
344char *
345authorized_keys_file2(struct passwd *pw)
346{
Damien Miller6476cad2005-06-16 13:18:34 +1000347 return expand_authorized_keys(options.authorized_keys_file2, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000348}
349
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000350/* return ok if key exists in sysfile or userfile */
351HostStatus
352check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
353 const char *sysfile, const char *userfile)
354{
355 Key *found;
356 char *user_hostfile;
357 struct stat st;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000358 HostStatus host_status;
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000359
360 /* Check if we know the host and its host key. */
361 found = key_new(key->type);
362 host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
363
364 if (host_status != HOST_OK && userfile != NULL) {
365 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
366 if (options.strict_modes &&
367 (stat(user_hostfile, &st) == 0) &&
368 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
Damien Miller9f0f5c62001-12-21 14:45:46 +1100369 (st.st_mode & 022) != 0)) {
Damien Miller996acd22003-04-09 20:59:48 +1000370 logit("Authentication refused for %.100s: "
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000371 "bad owner or modes for %.200s",
372 pw->pw_name, user_hostfile);
373 } else {
374 temporarily_use_uid(pw);
375 host_status = check_host_in_hostfile(user_hostfile,
376 host, key, found, NULL);
377 restore_uid();
378 }
379 xfree(user_hostfile);
380 }
381 key_free(found);
382
383 debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
384 "ok" : "not found", host);
385 return host_status;
386}
387
388
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000389/*
390 * Check a given file for security. This is defined as all components
Ben Lindstromd4ee3492002-08-20 18:42:13 +0000391 * of the path to the file must be owned by either the owner of
Ben Lindstrom60567ff2001-06-05 20:27:53 +0000392 * of the file or root and no directories must be group or world writable.
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000393 *
394 * XXX Should any specific check be done for sym links ?
395 *
396 * Takes an open file descriptor, the file name, a uid and and
397 * error buffer plus max size as arguments.
398 *
399 * Returns 0 on success and -1 on failure
400 */
401int
Ben Lindstrom248c0782001-07-04 03:40:39 +0000402secure_filename(FILE *f, const char *file, struct passwd *pw,
403 char *err, size_t errlen)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000404{
Ben Lindstrom248c0782001-07-04 03:40:39 +0000405 uid_t uid = pw->pw_uid;
Ben Lindstromc3e49e72001-10-03 17:55:26 +0000406 char buf[MAXPATHLEN], homedir[MAXPATHLEN];
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000407 char *cp;
Ben Lindstrom485075e2002-11-09 15:45:12 +0000408 int comparehome = 0;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000409 struct stat st;
410
411 if (realpath(file, buf) == NULL) {
412 snprintf(err, errlen, "realpath %s failed: %s", file,
413 strerror(errno));
414 return -1;
415 }
Ben Lindstrom485075e2002-11-09 15:45:12 +0000416 if (realpath(pw->pw_dir, homedir) != NULL)
417 comparehome = 1;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000418
419 /* check the open file to avoid races */
420 if (fstat(fileno(f), &st) < 0 ||
421 (st.st_uid != 0 && st.st_uid != uid) ||
422 (st.st_mode & 022) != 0) {
423 snprintf(err, errlen, "bad ownership or modes for file %s",
424 buf);
425 return -1;
426 }
427
428 /* for each component of the canonical path, walking upwards */
429 for (;;) {
430 if ((cp = dirname(buf)) == NULL) {
431 snprintf(err, errlen, "dirname() failed");
432 return -1;
433 }
434 strlcpy(buf, cp, sizeof(buf));
435
436 debug3("secure_filename: checking '%s'", buf);
437 if (stat(buf, &st) < 0 ||
438 (st.st_uid != 0 && st.st_uid != uid) ||
439 (st.st_mode & 022) != 0) {
Damien Miller9f0f5c62001-12-21 14:45:46 +1100440 snprintf(err, errlen,
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000441 "bad ownership or modes for directory %s", buf);
442 return -1;
443 }
444
Damien Miller0ae6e002001-07-14 12:21:34 +1000445 /* If are passed the homedir then we can stop */
Ben Lindstrom485075e2002-11-09 15:45:12 +0000446 if (comparehome && strcmp(homedir, buf) == 0) {
Damien Miller0ae6e002001-07-14 12:21:34 +1000447 debug3("secure_filename: terminating check at '%s'",
448 buf);
449 break;
450 }
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000451 /*
452 * dirname should always complete with a "/" path,
453 * but we can be paranoid and check for "." too
454 */
455 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
456 break;
457 }
458 return 0;
459}
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000460
461struct passwd *
462getpwnamallow(const char *user)
463{
Ben Lindstromb481e132002-03-22 01:35:47 +0000464#ifdef HAVE_LOGIN_CAP
465 extern login_cap_t *lc;
466#ifdef BSD_AUTH
467 auth_session_t *as;
468#endif
469#endif
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000470 struct passwd *pw;
471
Darren Tucker45150472006-07-12 22:34:17 +1000472 parse_server_match_config(&options, user,
473 get_canonical_hostname(options.use_dns), get_remote_ipaddr());
474
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000475 pw = getpwnam(user);
Damien Miller6f0a1882002-09-22 01:26:51 +1000476 if (pw == NULL) {
Damien Millera22f2d72004-07-21 20:48:24 +1000477 logit("Invalid user %.100s from %.100s",
Damien Miller6f0a1882002-09-22 01:26:51 +1000478 user, get_remote_ipaddr());
Darren Tucker97363a82003-05-02 23:42:25 +1000479#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker42d9dc72005-02-02 17:10:11 +1100480 record_failed_login(user,
481 get_canonical_hostname(options.use_dns), "ssh");
Ben Lindstromf5397c02002-11-09 16:11:10 +0000482#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100483#ifdef SSH_AUDIT_EVENTS
484 audit_event(SSH_INVALID_USER);
485#endif /* SSH_AUDIT_EVENTS */
Damien Miller6f0a1882002-09-22 01:26:51 +1000486 return (NULL);
487 }
488 if (!allowed_user(pw))
Ben Lindstromb481e132002-03-22 01:35:47 +0000489 return (NULL);
490#ifdef HAVE_LOGIN_CAP
491 if ((lc = login_getclass(pw->pw_class)) == NULL) {
492 debug("unable to get login class: %s", user);
493 return (NULL);
494 }
495#ifdef BSD_AUTH
496 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
Damien Miller13e35a02002-05-22 14:04:11 +1000497 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
Ben Lindstromb481e132002-03-22 01:35:47 +0000498 debug("Approval failure for %s", user);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000499 pw = NULL;
Ben Lindstromb481e132002-03-22 01:35:47 +0000500 }
501 if (as != NULL)
502 auth_close(as);
503#endif
504#endif
Ben Lindstromf34e4eb2002-03-22 03:08:30 +0000505 if (pw != NULL)
506 return (pwcopy(pw));
507 return (NULL);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000508}
Ben Lindstroma574cda2002-05-15 16:16:14 +0000509
510void
511auth_debug_add(const char *fmt,...)
512{
513 char buf[1024];
514 va_list args;
515
516 if (!auth_debug_init)
517 return;
518
519 va_start(args, fmt);
520 vsnprintf(buf, sizeof(buf), fmt, args);
521 va_end(args);
522 buffer_put_cstring(&auth_debug, buf);
523}
524
525void
526auth_debug_send(void)
527{
528 char *msg;
529
530 if (!auth_debug_init)
531 return;
532 while (buffer_len(&auth_debug)) {
533 msg = buffer_get_string(&auth_debug, NULL);
534 packet_send_debug("%s", msg);
535 xfree(msg);
536 }
537}
538
539void
540auth_debug_reset(void)
541{
542 if (auth_debug_init)
543 buffer_clear(&auth_debug);
544 else {
545 buffer_init(&auth_debug);
546 auth_debug_init = 1;
547 }
548}
Damien Miller856f0be2003-09-03 07:32:45 +1000549
550struct passwd *
551fakepw(void)
552{
553 static struct passwd fake;
554
555 memset(&fake, 0, sizeof(fake));
556 fake.pw_name = "NOUSER";
557 fake.pw_passwd =
Damien Miller787b2ec2003-11-21 23:56:47 +1100558 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
Damien Miller856f0be2003-09-03 07:32:45 +1000559 fake.pw_gecos = "NOUSER";
Darren Tucker1f8311c2004-05-13 16:39:33 +1000560 fake.pw_uid = (uid_t)-1;
561 fake.pw_gid = (gid_t)-1;
Damien Miller856f0be2003-09-03 07:32:45 +1000562#ifdef HAVE_PW_CLASS_IN_PASSWD
563 fake.pw_class = "";
564#endif
565 fake.pw_dir = "/nonexist";
566 fake.pw_shell = "/nonexist";
567
568 return (&fake);
569}