blob: fca373b8075b3f564a13e9f12ce854a00169eede [file] [log] [blame]
Damien Miller116e6df2002-05-22 15:06:28 +10001/*
Ben Lindstrom92a2e382001-03-05 06:59:27 +00002 * Copyright (c) 2000 Markus Friedl. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +11003 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Millerb38eff82000-04-01 11:09:21 +100023 */
24
25#include "includes.h"
Damien Millerf17883e2006-03-15 11:45:54 +110026RCSID("$OpenBSD: auth.c,v 1.62 2006/02/20 17:19:53 stevesk Exp $");
27
28#include <sys/types.h>
29#include <sys/stat.h>
Damien Millerb38eff82000-04-01 11:09:21 +100030
Damien Miller03e20032006-03-15 11:16:59 +110031#ifdef HAVE_PATHS_H
Damien Millera9263d02006-03-15 11:18:26 +110032# include <paths.h>
Damien Miller03e20032006-03-15 11:16:59 +110033#endif
Damien Millerd2c208a2000-05-17 22:00:02 +100034#ifdef HAVE_LOGIN_H
35#include <login.h>
36#endif
Darren Tucker15ee7482004-02-22 09:43:15 +110037#ifdef USE_SHADOW
Damien Miller1f335fb2000-06-26 11:31:33 +100038#include <shadow.h>
Darren Tucker15ee7482004-02-22 09:43:15 +110039#endif
Damien Millerb38eff82000-04-01 11:09:21 +100040
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000041#ifdef HAVE_LIBGEN_H
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000042#include <libgen.h>
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000043#endif
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000044
Ben Lindstrom226cfa02001-01-22 05:34:40 +000045#include "xmalloc.h"
46#include "match.h"
47#include "groupaccess.h"
48#include "log.h"
49#include "servconf.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100050#include "auth.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000051#include "auth-options.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000052#include "canohost.h"
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000053#include "buffer.h"
54#include "bufaux.h"
Ben Lindstrom83647ce2001-06-25 04:30:16 +000055#include "uidswap.h"
Ben Lindstrom7ebb6352002-03-22 03:04:08 +000056#include "misc.h"
Ben Lindstroma574cda2002-05-15 16:16:14 +000057#include "bufaux.h"
58#include "packet.h"
Darren Tucker42d9dc72005-02-02 17:10:11 +110059#include "loginrec.h"
Darren Tucker269a1ea2005-02-03 00:20:53 +110060#include "monitor_wrap.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100061
Damien Millerb38eff82000-04-01 11:09:21 +100062/* import */
63extern ServerOptions options;
Darren Tuckerb9aa0a02003-07-08 22:59:59 +100064extern Buffer loginmsg;
Damien Millerb38eff82000-04-01 11:09:21 +100065
Ben Lindstroma574cda2002-05-15 16:16:14 +000066/* Debugging messages */
67Buffer auth_debug;
68int auth_debug_init;
69
Damien Millerb38eff82000-04-01 11:09:21 +100070/*
Kevin Steves7b61cfa2001-01-14 19:11:00 +000071 * Check if the user is allowed to log in via ssh. If user is listed
72 * in DenyUsers or one of user's groups is listed in DenyGroups, false
73 * will be returned. If AllowUsers isn't empty and user isn't listed
74 * there, or if AllowGroups isn't empty and one of user's groups isn't
75 * listed there, false will be returned.
Damien Millerb38eff82000-04-01 11:09:21 +100076 * If the user's shell is not executable, false will be returned.
Damien Miller4af51302000-04-16 11:18:38 +100077 * Otherwise true is returned.
Damien Millerb38eff82000-04-01 11:09:21 +100078 */
Damien Millereba71ba2000-04-29 23:57:08 +100079int
Damien Millerb38eff82000-04-01 11:09:21 +100080allowed_user(struct passwd * pw)
81{
82 struct stat st;
Darren Tucker43a0dc62003-08-26 14:22:12 +100083 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
Damien Millere7cf07c2001-03-20 09:15:57 +110084 char *shell;
Damien Millereccb9de2005-06-17 12:59:34 +100085 u_int i;
Darren Tucker15ee7482004-02-22 09:43:15 +110086#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +100087 struct spwd *spw = NULL;
Tim Rice458c6bf2003-01-08 20:04:27 -080088#endif
Damien Millerb38eff82000-04-01 11:09:21 +100089
90 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
Kevin Steves7b61cfa2001-01-14 19:11:00 +000091 if (!pw || !pw->pw_name)
Damien Millerb38eff82000-04-01 11:09:21 +100092 return 0;
93
Darren Tucker15ee7482004-02-22 09:43:15 +110094#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +100095 if (!options.use_pam)
96 spw = getspnam(pw->pw_name);
97#ifdef HAS_SHADOW_EXPIRE
Darren Tucker15ee7482004-02-22 09:43:15 +110098 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
99 return 0;
Darren Tuckere41bba52003-08-25 11:51:19 +1000100#endif /* HAS_SHADOW_EXPIRE */
Darren Tucker15ee7482004-02-22 09:43:15 +1100101#endif /* USE_SHADOW */
Darren Tuckere41bba52003-08-25 11:51:19 +1000102
Damien Millera8e06ce2003-11-21 23:48:55 +1100103 /* grab passwd field for locked account check */
Darren Tucker15ee7482004-02-22 09:43:15 +1100104#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000105 if (spw != NULL)
Tim Rice66fd2172005-08-31 09:59:49 -0700106#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
Tim Rice2291c002005-08-26 13:15:19 -0700107 passwd = get_iaf_password(pw);
108#else
Darren Tuckere41bba52003-08-25 11:51:19 +1000109 passwd = spw->sp_pwdp;
Tim Rice66fd2172005-08-31 09:59:49 -0700110#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000111#else
112 passwd = pw->pw_passwd;
Damien Miller06817f92003-01-07 23:55:59 +1100113#endif
114
Damien Millera8e06ce2003-11-21 23:48:55 +1100115 /* check for locked account */
Darren Tucker43a0dc62003-08-26 14:22:12 +1000116 if (!options.use_pam && passwd && *passwd) {
Darren Tuckere41bba52003-08-25 11:51:19 +1000117 int locked = 0;
118
119#ifdef LOCKED_PASSWD_STRING
120 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
121 locked = 1;
122#endif
123#ifdef LOCKED_PASSWD_PREFIX
124 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
125 strlen(LOCKED_PASSWD_PREFIX)) == 0)
126 locked = 1;
127#endif
128#ifdef LOCKED_PASSWD_SUBSTR
129 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
130 locked = 1;
131#endif
Tim Rice66fd2172005-08-31 09:59:49 -0700132#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
133 free(passwd);
134#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000135 if (locked) {
136 logit("User %.100s not allowed because account is locked",
137 pw->pw_name);
138 return 0;
139 }
140 }
141
Damien Milleref7df542000-05-19 00:03:23 +1000142 /*
143 * Get the shell from the password data. An empty shell field is
144 * legal, and means /bin/sh.
145 */
146 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
147
148 /* deny if shell does not exists or is not executable */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000149 if (stat(shell, &st) != 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000150 logit("User %.100s not allowed because shell %.100s does not exist",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000151 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000152 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000153 }
Ben Lindstromb61e6df2002-03-22 01:15:33 +0000154 if (S_ISREG(st.st_mode) == 0 ||
155 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000156 logit("User %.100s not allowed because shell %.100s is not executable",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000157 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000158 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000159 }
Damien Millerb38eff82000-04-01 11:09:21 +1000160
Darren Tuckera8f553d2005-03-14 23:17:27 +1100161 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
162 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Damien Miller3a961dc2003-06-03 10:25:48 +1000163 hostname = get_canonical_hostname(options.use_dns);
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000164 ipaddr = get_remote_ipaddr();
165 }
166
Damien Millerb38eff82000-04-01 11:09:21 +1000167 /* Return false if user is listed in DenyUsers */
168 if (options.num_deny_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000169 for (i = 0; i < options.num_deny_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000170 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000171 options.deny_users[i])) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100172 logit("User %.100s from %.100s not allowed "
173 "because listed in DenyUsers",
174 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000175 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000176 }
Damien Millerb38eff82000-04-01 11:09:21 +1000177 }
178 /* Return false if AllowUsers isn't empty and user isn't listed there */
179 if (options.num_allow_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000180 for (i = 0; i < options.num_allow_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000181 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom60260022001-07-04 04:56:44 +0000182 options.allow_users[i]))
Damien Millerb38eff82000-04-01 11:09:21 +1000183 break;
184 /* i < options.num_allow_users iff we break for loop */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000185 if (i >= options.num_allow_users) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100186 logit("User %.100s from %.100s not allowed because "
187 "not listed in AllowUsers", 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 }
Damien Millerb38eff82000-04-01 11:09:21 +1000191 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000192 /* Get the user's group access list (primary and supplementary) */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000193 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100194 logit("User %.100s from %.100s not allowed because "
195 "not in any group", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000196 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000197 }
Damien Millerb38eff82000-04-01 11:09:21 +1000198
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000199 /* Return false if one of user's groups is listed in DenyGroups */
200 if (options.num_deny_groups > 0)
201 if (ga_match(options.deny_groups,
202 options.num_deny_groups)) {
203 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100204 logit("User %.100s from %.100s not allowed "
205 "because a group is listed in DenyGroups",
206 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000207 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000208 }
Damien Millerb38eff82000-04-01 11:09:21 +1000209 /*
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000210 * Return false if AllowGroups isn't empty and one of user's groups
Damien Millerb38eff82000-04-01 11:09:21 +1000211 * isn't listed there
212 */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000213 if (options.num_allow_groups > 0)
214 if (!ga_match(options.allow_groups,
215 options.num_allow_groups)) {
216 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100217 logit("User %.100s from %.100s not allowed "
218 "because none of user's groups are listed "
219 "in AllowGroups", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000220 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000221 }
222 ga_free();
Damien Millerb38eff82000-04-01 11:09:21 +1000223 }
224
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000225#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
Darren Tucker691d5232005-02-15 21:45:57 +1100226 if (!sys_auth_allowed_user(pw, &loginmsg))
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000227 return 0;
228#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000229
230 /* We found no reason not to let this user try to log on... */
231 return 1;
232}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000233
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000234void
235auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
236{
237 void (*authlog) (const char *fmt,...) = verbose;
238 char *authmsg;
239
240 /* Raise logging level */
241 if (authenticated == 1 ||
242 !authctxt->valid ||
Darren Tucker89413db2004-05-24 10:36:23 +1000243 authctxt->failures >= options.max_authtries / 2 ||
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000244 strcmp(method, "password") == 0)
Damien Miller2a3f20e2003-04-09 21:12:00 +1000245 authlog = logit;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000246
247 if (authctxt->postponed)
248 authmsg = "Postponed";
249 else
250 authmsg = authenticated ? "Accepted" : "Failed";
251
252 authlog("%s %s for %s%.100s from %.200s port %d%s",
253 authmsg,
254 method,
Darren Tucker5cb30ad2004-08-12 22:40:24 +1000255 authctxt->valid ? "" : "invalid user ",
Damien Millerf6552072001-11-12 11:06:06 +1100256 authctxt->user,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000257 get_remote_ipaddr(),
258 get_remote_port(),
259 info);
Ben Lindstrome06eb682002-07-04 00:27:21 +0000260
Darren Tucker97363a82003-05-02 23:42:25 +1000261#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker2fba9932005-02-02 23:30:24 +1100262 if (authenticated == 0 && !authctxt->postponed &&
263 (strcmp(method, "password") == 0 ||
Darren Tucker40d9a632005-02-04 15:19:44 +1100264 strncmp(method, "keyboard-interactive", 20) == 0 ||
265 strcmp(method, "challenge-response") == 0))
Darren Tucker42d9dc72005-02-02 17:10:11 +1100266 record_failed_login(authctxt->user,
267 get_canonical_hostname(options.use_dns), "ssh");
Darren Tucker97363a82003-05-02 23:42:25 +1000268#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100269#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +1100270 if (authenticated == 0 && !authctxt->postponed) {
271 ssh_audit_event_t event;
272
273 debug3("audit failed auth attempt, method %s euid %d",
274 method, (int)geteuid());
275 /*
276 * Because the auth loop is used in both monitor and slave,
277 * we must be careful to send each event only once and with
278 * enough privs to write the event.
279 */
280 event = audit_classify_auth(method);
281 switch(event) {
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100282 case SSH_AUTH_FAIL_NONE:
283 case SSH_AUTH_FAIL_PASSWD:
284 case SSH_AUTH_FAIL_KBDINT:
Darren Tucker269a1ea2005-02-03 00:20:53 +1100285 if (geteuid() == 0)
286 audit_event(event);
287 break;
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100288 case SSH_AUTH_FAIL_PUBKEY:
289 case SSH_AUTH_FAIL_HOSTBASED:
290 case SSH_AUTH_FAIL_GSSAPI:
Darren Tucker269a1ea2005-02-03 00:20:53 +1100291 /*
292 * This is required to handle the case where privsep
293 * is enabled but it's root logging in, since
294 * use_privsep won't be cleared until after a
295 * successful login.
296 */
297 if (geteuid() == 0)
298 audit_event(event);
299 else
300 PRIVSEP(audit_event(event));
301 break;
302 default:
303 error("unknown authentication audit event %d", event);
304 }
305 }
306#endif
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000307}
308
309/*
Ben Lindstromd8a90212001-02-15 03:08:27 +0000310 * Check whether root logins are disallowed.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000311 */
312int
Ben Lindstromd8a90212001-02-15 03:08:27 +0000313auth_root_allowed(char *method)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000314{
Ben Lindstromd8a90212001-02-15 03:08:27 +0000315 switch (options.permit_root_login) {
316 case PERMIT_YES:
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000317 return 1;
Ben Lindstromd8a90212001-02-15 03:08:27 +0000318 break;
319 case PERMIT_NO_PASSWD:
320 if (strcmp(method, "password") != 0)
321 return 1;
322 break;
323 case PERMIT_FORCED_ONLY:
324 if (forced_command) {
Damien Miller996acd22003-04-09 20:59:48 +1000325 logit("Root login accepted for forced command.");
Ben Lindstromd8a90212001-02-15 03:08:27 +0000326 return 1;
327 }
328 break;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000329 }
Damien Miller996acd22003-04-09 20:59:48 +1000330 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
Ben Lindstromd8a90212001-02-15 03:08:27 +0000331 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000332}
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000333
334
335/*
336 * Given a template and a passwd structure, build a filename
337 * by substituting % tokenised options. Currently, %% becomes '%',
338 * %h becomes the home directory and %u the username.
339 *
340 * This returns a buffer allocated by xmalloc.
341 */
Damien Miller6476cad2005-06-16 13:18:34 +1000342static char *
343expand_authorized_keys(const char *filename, struct passwd *pw)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000344{
Damien Miller6476cad2005-06-16 13:18:34 +1000345 char *file, *ret;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000346
Damien Miller6476cad2005-06-16 13:18:34 +1000347 file = percent_expand(filename, "h", pw->pw_dir,
348 "u", pw->pw_name, (char *)NULL);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000349
350 /*
351 * Ensure that filename starts anchored. If not, be backward
352 * compatible and prepend the '%h/'
353 */
Damien Miller6476cad2005-06-16 13:18:34 +1000354 if (*file == '/')
355 return (file);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000356
Damien Miller6476cad2005-06-16 13:18:34 +1000357 ret = xmalloc(MAXPATHLEN);
358 if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN ||
359 strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN ||
360 strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
361 fatal("expand_authorized_keys: path too long");
362
363 xfree(file);
364 return (ret);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000365}
366
367char *
368authorized_keys_file(struct passwd *pw)
369{
Damien Miller6476cad2005-06-16 13:18:34 +1000370 return expand_authorized_keys(options.authorized_keys_file, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000371}
372
373char *
374authorized_keys_file2(struct passwd *pw)
375{
Damien Miller6476cad2005-06-16 13:18:34 +1000376 return expand_authorized_keys(options.authorized_keys_file2, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000377}
378
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000379/* return ok if key exists in sysfile or userfile */
380HostStatus
381check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
382 const char *sysfile, const char *userfile)
383{
384 Key *found;
385 char *user_hostfile;
386 struct stat st;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000387 HostStatus host_status;
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000388
389 /* Check if we know the host and its host key. */
390 found = key_new(key->type);
391 host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
392
393 if (host_status != HOST_OK && userfile != NULL) {
394 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
395 if (options.strict_modes &&
396 (stat(user_hostfile, &st) == 0) &&
397 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
Damien Miller9f0f5c62001-12-21 14:45:46 +1100398 (st.st_mode & 022) != 0)) {
Damien Miller996acd22003-04-09 20:59:48 +1000399 logit("Authentication refused for %.100s: "
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000400 "bad owner or modes for %.200s",
401 pw->pw_name, user_hostfile);
402 } 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 */
430int
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
Damien Miller0ae6e002001-07-14 12:21:34 +1000474 /* If are passed 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
490struct passwd *
491getpwnamallow(const char *user)
492{
Ben Lindstromb481e132002-03-22 01:35:47 +0000493#ifdef HAVE_LOGIN_CAP
494 extern login_cap_t *lc;
495#ifdef BSD_AUTH
496 auth_session_t *as;
497#endif
498#endif
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000499 struct passwd *pw;
500
501 pw = getpwnam(user);
Damien Miller6f0a1882002-09-22 01:26:51 +1000502 if (pw == NULL) {
Damien Millera22f2d72004-07-21 20:48:24 +1000503 logit("Invalid user %.100s from %.100s",
Damien Miller6f0a1882002-09-22 01:26:51 +1000504 user, get_remote_ipaddr());
Darren Tucker97363a82003-05-02 23:42:25 +1000505#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker42d9dc72005-02-02 17:10:11 +1100506 record_failed_login(user,
507 get_canonical_hostname(options.use_dns), "ssh");
Ben Lindstromf5397c02002-11-09 16:11:10 +0000508#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100509#ifdef SSH_AUDIT_EVENTS
510 audit_event(SSH_INVALID_USER);
511#endif /* SSH_AUDIT_EVENTS */
Damien Miller6f0a1882002-09-22 01:26:51 +1000512 return (NULL);
513 }
514 if (!allowed_user(pw))
Ben Lindstromb481e132002-03-22 01:35:47 +0000515 return (NULL);
516#ifdef HAVE_LOGIN_CAP
517 if ((lc = login_getclass(pw->pw_class)) == NULL) {
518 debug("unable to get login class: %s", user);
519 return (NULL);
520 }
521#ifdef BSD_AUTH
522 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
Damien Miller13e35a02002-05-22 14:04:11 +1000523 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
Ben Lindstromb481e132002-03-22 01:35:47 +0000524 debug("Approval failure for %s", user);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000525 pw = NULL;
Ben Lindstromb481e132002-03-22 01:35:47 +0000526 }
527 if (as != NULL)
528 auth_close(as);
529#endif
530#endif
Ben Lindstromf34e4eb2002-03-22 03:08:30 +0000531 if (pw != NULL)
532 return (pwcopy(pw));
533 return (NULL);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000534}
Ben Lindstroma574cda2002-05-15 16:16:14 +0000535
536void
537auth_debug_add(const char *fmt,...)
538{
539 char buf[1024];
540 va_list args;
541
542 if (!auth_debug_init)
543 return;
544
545 va_start(args, fmt);
546 vsnprintf(buf, sizeof(buf), fmt, args);
547 va_end(args);
548 buffer_put_cstring(&auth_debug, buf);
549}
550
551void
552auth_debug_send(void)
553{
554 char *msg;
555
556 if (!auth_debug_init)
557 return;
558 while (buffer_len(&auth_debug)) {
559 msg = buffer_get_string(&auth_debug, NULL);
560 packet_send_debug("%s", msg);
561 xfree(msg);
562 }
563}
564
565void
566auth_debug_reset(void)
567{
568 if (auth_debug_init)
569 buffer_clear(&auth_debug);
570 else {
571 buffer_init(&auth_debug);
572 auth_debug_init = 1;
573 }
574}
Damien Miller856f0be2003-09-03 07:32:45 +1000575
576struct passwd *
577fakepw(void)
578{
579 static struct passwd fake;
580
581 memset(&fake, 0, sizeof(fake));
582 fake.pw_name = "NOUSER";
583 fake.pw_passwd =
Damien Miller787b2ec2003-11-21 23:56:47 +1100584 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
Damien Miller856f0be2003-09-03 07:32:45 +1000585 fake.pw_gecos = "NOUSER";
Darren Tucker1f8311c2004-05-13 16:39:33 +1000586 fake.pw_uid = (uid_t)-1;
587 fake.pw_gid = (gid_t)-1;
Damien Miller856f0be2003-09-03 07:32:45 +1000588#ifdef HAVE_PW_CLASS_IN_PASSWD
589 fake.pw_class = "";
590#endif
591 fake.pw_dir = "/nonexist";
592 fake.pw_shell = "/nonexist";
593
594 return (&fake);
595}