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Damien Miller9f2abc42006-07-10 20:53:08 +10001/* $OpenBSD: auth.c,v 1.68 2006/07/06 16:03:53 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 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 Miller9f2abc42006-07-10 20:53:08 +100034#include <pwd.h>
Damien Millerd2c208a2000-05-17 22:00:02 +100035#ifdef HAVE_LOGIN_H
36#include <login.h>
37#endif
Darren Tucker15ee7482004-02-22 09:43:15 +110038#ifdef USE_SHADOW
Damien Miller1f335fb2000-06-26 11:31:33 +100039#include <shadow.h>
Darren Tucker15ee7482004-02-22 09:43:15 +110040#endif
Damien Millerb38eff82000-04-01 11:09:21 +100041
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000042#ifdef HAVE_LIBGEN_H
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000043#include <libgen.h>
Ben Lindstrom68c3ce12001-06-10 17:24:51 +000044#endif
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000045
Ben Lindstrom226cfa02001-01-22 05:34:40 +000046#include "xmalloc.h"
47#include "match.h"
48#include "groupaccess.h"
49#include "log.h"
50#include "servconf.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100051#include "auth.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000052#include "auth-options.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000053#include "canohost.h"
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +000054#include "buffer.h"
55#include "bufaux.h"
Ben Lindstrom83647ce2001-06-25 04:30:16 +000056#include "uidswap.h"
Ben Lindstrom7ebb6352002-03-22 03:04:08 +000057#include "misc.h"
Ben Lindstroma574cda2002-05-15 16:16:14 +000058#include "bufaux.h"
59#include "packet.h"
Darren Tucker42d9dc72005-02-02 17:10:11 +110060#include "loginrec.h"
Darren Tucker269a1ea2005-02-03 00:20:53 +110061#include "monitor_wrap.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100062
Damien Millerb38eff82000-04-01 11:09:21 +100063/* import */
64extern ServerOptions options;
Damien Miller7a8f5b32006-03-31 23:14:23 +110065extern int use_privsep;
Darren Tuckerb9aa0a02003-07-08 22:59:59 +100066extern Buffer loginmsg;
Damien Millerb38eff82000-04-01 11:09:21 +100067
Ben Lindstroma574cda2002-05-15 16:16:14 +000068/* Debugging messages */
69Buffer auth_debug;
70int auth_debug_init;
71
Damien Millerb38eff82000-04-01 11:09:21 +100072/*
Kevin Steves7b61cfa2001-01-14 19:11:00 +000073 * Check if the user is allowed to log in via ssh. If user is listed
74 * in DenyUsers or one of user's groups is listed in DenyGroups, false
75 * will be returned. If AllowUsers isn't empty and user isn't listed
76 * there, or if AllowGroups isn't empty and one of user's groups isn't
77 * listed there, false will be returned.
Damien Millerb38eff82000-04-01 11:09:21 +100078 * If the user's shell is not executable, false will be returned.
Damien Miller4af51302000-04-16 11:18:38 +100079 * Otherwise true is returned.
Damien Millerb38eff82000-04-01 11:09:21 +100080 */
Damien Millereba71ba2000-04-29 23:57:08 +100081int
Damien Millerb38eff82000-04-01 11:09:21 +100082allowed_user(struct passwd * pw)
83{
84 struct stat st;
Darren Tucker43a0dc62003-08-26 14:22:12 +100085 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
Damien Millere7cf07c2001-03-20 09:15:57 +110086 char *shell;
Damien Millereccb9de2005-06-17 12:59:34 +100087 u_int i;
Darren Tucker15ee7482004-02-22 09:43:15 +110088#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +100089 struct spwd *spw = NULL;
Tim Rice458c6bf2003-01-08 20:04:27 -080090#endif
Damien Millerb38eff82000-04-01 11:09:21 +100091
92 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
Kevin Steves7b61cfa2001-01-14 19:11:00 +000093 if (!pw || !pw->pw_name)
Damien Millerb38eff82000-04-01 11:09:21 +100094 return 0;
95
Darren Tucker15ee7482004-02-22 09:43:15 +110096#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +100097 if (!options.use_pam)
98 spw = getspnam(pw->pw_name);
99#ifdef HAS_SHADOW_EXPIRE
Darren Tucker15ee7482004-02-22 09:43:15 +1100100 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
101 return 0;
Darren Tuckere41bba52003-08-25 11:51:19 +1000102#endif /* HAS_SHADOW_EXPIRE */
Darren Tucker15ee7482004-02-22 09:43:15 +1100103#endif /* USE_SHADOW */
Darren Tuckere41bba52003-08-25 11:51:19 +1000104
Damien Millera8e06ce2003-11-21 23:48:55 +1100105 /* grab passwd field for locked account check */
Darren Tucker15ee7482004-02-22 09:43:15 +1100106#ifdef USE_SHADOW
Darren Tuckere41bba52003-08-25 11:51:19 +1000107 if (spw != NULL)
Tim Rice66fd2172005-08-31 09:59:49 -0700108#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
Tim Rice2291c002005-08-26 13:15:19 -0700109 passwd = get_iaf_password(pw);
110#else
Darren Tuckere41bba52003-08-25 11:51:19 +1000111 passwd = spw->sp_pwdp;
Tim Rice66fd2172005-08-31 09:59:49 -0700112#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000113#else
114 passwd = pw->pw_passwd;
Damien Miller06817f92003-01-07 23:55:59 +1100115#endif
116
Damien Millera8e06ce2003-11-21 23:48:55 +1100117 /* check for locked account */
Darren Tucker43a0dc62003-08-26 14:22:12 +1000118 if (!options.use_pam && passwd && *passwd) {
Darren Tuckere41bba52003-08-25 11:51:19 +1000119 int locked = 0;
120
121#ifdef LOCKED_PASSWD_STRING
122 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
123 locked = 1;
124#endif
125#ifdef LOCKED_PASSWD_PREFIX
126 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
127 strlen(LOCKED_PASSWD_PREFIX)) == 0)
128 locked = 1;
129#endif
130#ifdef LOCKED_PASSWD_SUBSTR
131 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
132 locked = 1;
133#endif
Tim Rice66fd2172005-08-31 09:59:49 -0700134#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
135 free(passwd);
136#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
Darren Tuckere41bba52003-08-25 11:51:19 +1000137 if (locked) {
138 logit("User %.100s not allowed because account is locked",
139 pw->pw_name);
140 return 0;
141 }
142 }
143
Damien Milleref7df542000-05-19 00:03:23 +1000144 /*
145 * Get the shell from the password data. An empty shell field is
146 * legal, and means /bin/sh.
147 */
148 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
149
150 /* deny if shell does not exists or is not executable */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000151 if (stat(shell, &st) != 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000152 logit("User %.100s not allowed because shell %.100s does not exist",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000153 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000154 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000155 }
Ben Lindstromb61e6df2002-03-22 01:15:33 +0000156 if (S_ISREG(st.st_mode) == 0 ||
157 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
Damien Miller996acd22003-04-09 20:59:48 +1000158 logit("User %.100s not allowed because shell %.100s is not executable",
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000159 pw->pw_name, shell);
Damien Millerb38eff82000-04-01 11:09:21 +1000160 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000161 }
Damien Millerb38eff82000-04-01 11:09:21 +1000162
Darren Tuckera8f553d2005-03-14 23:17:27 +1100163 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
164 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Damien Miller3a961dc2003-06-03 10:25:48 +1000165 hostname = get_canonical_hostname(options.use_dns);
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000166 ipaddr = get_remote_ipaddr();
167 }
168
Damien Millerb38eff82000-04-01 11:09:21 +1000169 /* Return false if user is listed in DenyUsers */
170 if (options.num_deny_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000171 for (i = 0; i < options.num_deny_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000172 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000173 options.deny_users[i])) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100174 logit("User %.100s from %.100s not allowed "
175 "because listed in DenyUsers",
176 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000177 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000178 }
Damien Millerb38eff82000-04-01 11:09:21 +1000179 }
180 /* Return false if AllowUsers isn't empty and user isn't listed there */
181 if (options.num_allow_users > 0) {
Damien Millerb38eff82000-04-01 11:09:21 +1000182 for (i = 0; i < options.num_allow_users; i++)
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000183 if (match_user(pw->pw_name, hostname, ipaddr,
Ben Lindstrom60260022001-07-04 04:56:44 +0000184 options.allow_users[i]))
Damien Millerb38eff82000-04-01 11:09:21 +1000185 break;
186 /* i < options.num_allow_users iff we break for loop */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000187 if (i >= options.num_allow_users) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100188 logit("User %.100s from %.100s not allowed because "
189 "not listed in AllowUsers", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000190 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000191 }
Damien Millerb38eff82000-04-01 11:09:21 +1000192 }
Damien Millerb38eff82000-04-01 11:09:21 +1000193 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000194 /* Get the user's group access list (primary and supplementary) */
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000195 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
Darren Tucker094cd0b2005-01-24 21:56:48 +1100196 logit("User %.100s from %.100s not allowed because "
197 "not in any group", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000198 return 0;
Ben Lindstrom6ef9ec62002-03-05 01:40:37 +0000199 }
Damien Millerb38eff82000-04-01 11:09:21 +1000200
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000201 /* Return false if one of user's groups is listed in DenyGroups */
202 if (options.num_deny_groups > 0)
203 if (ga_match(options.deny_groups,
204 options.num_deny_groups)) {
205 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100206 logit("User %.100s from %.100s not allowed "
207 "because a group is listed in DenyGroups",
208 pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000209 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000210 }
Damien Millerb38eff82000-04-01 11:09:21 +1000211 /*
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000212 * Return false if AllowGroups isn't empty and one of user's groups
Damien Millerb38eff82000-04-01 11:09:21 +1000213 * isn't listed there
214 */
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000215 if (options.num_allow_groups > 0)
216 if (!ga_match(options.allow_groups,
217 options.num_allow_groups)) {
218 ga_free();
Darren Tucker094cd0b2005-01-24 21:56:48 +1100219 logit("User %.100s from %.100s not allowed "
220 "because none of user's groups are listed "
221 "in AllowGroups", pw->pw_name, hostname);
Damien Millerb38eff82000-04-01 11:09:21 +1000222 return 0;
Kevin Steves7b61cfa2001-01-14 19:11:00 +0000223 }
224 ga_free();
Damien Millerb38eff82000-04-01 11:09:21 +1000225 }
226
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000227#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
Darren Tucker691d5232005-02-15 21:45:57 +1100228 if (!sys_auth_allowed_user(pw, &loginmsg))
Darren Tucker0a9d43d2004-06-23 13:45:24 +1000229 return 0;
230#endif
Damien Millerb38eff82000-04-01 11:09:21 +1000231
232 /* We found no reason not to let this user try to log on... */
233 return 1;
234}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000235
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000236void
237auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
238{
239 void (*authlog) (const char *fmt,...) = verbose;
240 char *authmsg;
241
Damien Miller7a8f5b32006-03-31 23:14:23 +1100242 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
243 return;
244
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000245 /* Raise logging level */
246 if (authenticated == 1 ||
247 !authctxt->valid ||
Darren Tucker89413db2004-05-24 10:36:23 +1000248 authctxt->failures >= options.max_authtries / 2 ||
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000249 strcmp(method, "password") == 0)
Damien Miller2a3f20e2003-04-09 21:12:00 +1000250 authlog = logit;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000251
252 if (authctxt->postponed)
253 authmsg = "Postponed";
254 else
255 authmsg = authenticated ? "Accepted" : "Failed";
256
257 authlog("%s %s for %s%.100s from %.200s port %d%s",
258 authmsg,
259 method,
Darren Tucker5cb30ad2004-08-12 22:40:24 +1000260 authctxt->valid ? "" : "invalid user ",
Damien Millerf6552072001-11-12 11:06:06 +1100261 authctxt->user,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000262 get_remote_ipaddr(),
263 get_remote_port(),
264 info);
Ben Lindstrome06eb682002-07-04 00:27:21 +0000265
Darren Tucker97363a82003-05-02 23:42:25 +1000266#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker2fba9932005-02-02 23:30:24 +1100267 if (authenticated == 0 && !authctxt->postponed &&
268 (strcmp(method, "password") == 0 ||
Darren Tucker40d9a632005-02-04 15:19:44 +1100269 strncmp(method, "keyboard-interactive", 20) == 0 ||
270 strcmp(method, "challenge-response") == 0))
Darren Tucker42d9dc72005-02-02 17:10:11 +1100271 record_failed_login(authctxt->user,
272 get_canonical_hostname(options.use_dns), "ssh");
Darren Tucker97363a82003-05-02 23:42:25 +1000273#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100274#ifdef SSH_AUDIT_EVENTS
Darren Tuckerf14b2aa2006-05-21 18:26:40 +1000275 if (authenticated == 0 && !authctxt->postponed)
276 audit_event(audit_classify_auth(method));
Darren Tucker269a1ea2005-02-03 00:20:53 +1100277#endif
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000278}
279
280/*
Ben Lindstromd8a90212001-02-15 03:08:27 +0000281 * Check whether root logins are disallowed.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000282 */
283int
Ben Lindstromd8a90212001-02-15 03:08:27 +0000284auth_root_allowed(char *method)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000285{
Ben Lindstromd8a90212001-02-15 03:08:27 +0000286 switch (options.permit_root_login) {
287 case PERMIT_YES:
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000288 return 1;
Ben Lindstromd8a90212001-02-15 03:08:27 +0000289 case PERMIT_NO_PASSWD:
290 if (strcmp(method, "password") != 0)
291 return 1;
292 break;
293 case PERMIT_FORCED_ONLY:
294 if (forced_command) {
Damien Miller996acd22003-04-09 20:59:48 +1000295 logit("Root login accepted for forced command.");
Ben Lindstromd8a90212001-02-15 03:08:27 +0000296 return 1;
297 }
298 break;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000299 }
Damien Miller996acd22003-04-09 20:59:48 +1000300 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
Ben Lindstromd8a90212001-02-15 03:08:27 +0000301 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000302}
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000303
304
305/*
306 * Given a template and a passwd structure, build a filename
307 * by substituting % tokenised options. Currently, %% becomes '%',
308 * %h becomes the home directory and %u the username.
309 *
310 * This returns a buffer allocated by xmalloc.
311 */
Damien Miller6476cad2005-06-16 13:18:34 +1000312static char *
313expand_authorized_keys(const char *filename, struct passwd *pw)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000314{
Damien Miller07d86be2006-03-26 14:19:21 +1100315 char *file, ret[MAXPATHLEN];
316 int i;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000317
Damien Miller6476cad2005-06-16 13:18:34 +1000318 file = percent_expand(filename, "h", pw->pw_dir,
319 "u", pw->pw_name, (char *)NULL);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000320
321 /*
322 * Ensure that filename starts anchored. If not, be backward
323 * compatible and prepend the '%h/'
324 */
Damien Miller6476cad2005-06-16 13:18:34 +1000325 if (*file == '/')
326 return (file);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000327
Damien Miller07d86be2006-03-26 14:19:21 +1100328 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
329 if (i < 0 || (size_t)i >= sizeof(ret))
Damien Miller6476cad2005-06-16 13:18:34 +1000330 fatal("expand_authorized_keys: path too long");
Damien Miller6476cad2005-06-16 13:18:34 +1000331 xfree(file);
Damien Miller07d86be2006-03-26 14:19:21 +1100332 return (xstrdup(ret));
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000333}
334
335char *
336authorized_keys_file(struct passwd *pw)
337{
Damien Miller6476cad2005-06-16 13:18:34 +1000338 return expand_authorized_keys(options.authorized_keys_file, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000339}
340
341char *
342authorized_keys_file2(struct passwd *pw)
343{
Damien Miller6476cad2005-06-16 13:18:34 +1000344 return expand_authorized_keys(options.authorized_keys_file2, pw);
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000345}
346
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000347/* return ok if key exists in sysfile or userfile */
348HostStatus
349check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
350 const char *sysfile, const char *userfile)
351{
352 Key *found;
353 char *user_hostfile;
354 struct stat st;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000355 HostStatus host_status;
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000356
357 /* Check if we know the host and its host key. */
358 found = key_new(key->type);
359 host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
360
361 if (host_status != HOST_OK && userfile != NULL) {
362 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
363 if (options.strict_modes &&
364 (stat(user_hostfile, &st) == 0) &&
365 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
Damien Miller9f0f5c62001-12-21 14:45:46 +1100366 (st.st_mode & 022) != 0)) {
Damien Miller996acd22003-04-09 20:59:48 +1000367 logit("Authentication refused for %.100s: "
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000368 "bad owner or modes for %.200s",
369 pw->pw_name, user_hostfile);
370 } else {
371 temporarily_use_uid(pw);
372 host_status = check_host_in_hostfile(user_hostfile,
373 host, key, found, NULL);
374 restore_uid();
375 }
376 xfree(user_hostfile);
377 }
378 key_free(found);
379
380 debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
381 "ok" : "not found", host);
382 return host_status;
383}
384
385
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000386/*
387 * Check a given file for security. This is defined as all components
Ben Lindstromd4ee3492002-08-20 18:42:13 +0000388 * of the path to the file must be owned by either the owner of
Ben Lindstrom60567ff2001-06-05 20:27:53 +0000389 * of the file or root and no directories must be group or world writable.
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000390 *
391 * XXX Should any specific check be done for sym links ?
392 *
393 * Takes an open file descriptor, the file name, a uid and and
394 * error buffer plus max size as arguments.
395 *
396 * Returns 0 on success and -1 on failure
397 */
398int
Ben Lindstrom248c0782001-07-04 03:40:39 +0000399secure_filename(FILE *f, const char *file, struct passwd *pw,
400 char *err, size_t errlen)
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000401{
Ben Lindstrom248c0782001-07-04 03:40:39 +0000402 uid_t uid = pw->pw_uid;
Ben Lindstromc3e49e72001-10-03 17:55:26 +0000403 char buf[MAXPATHLEN], homedir[MAXPATHLEN];
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000404 char *cp;
Ben Lindstrom485075e2002-11-09 15:45:12 +0000405 int comparehome = 0;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000406 struct stat st;
407
408 if (realpath(file, buf) == NULL) {
409 snprintf(err, errlen, "realpath %s failed: %s", file,
410 strerror(errno));
411 return -1;
412 }
Ben Lindstrom485075e2002-11-09 15:45:12 +0000413 if (realpath(pw->pw_dir, homedir) != NULL)
414 comparehome = 1;
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000415
416 /* check the open file to avoid races */
417 if (fstat(fileno(f), &st) < 0 ||
418 (st.st_uid != 0 && st.st_uid != uid) ||
419 (st.st_mode & 022) != 0) {
420 snprintf(err, errlen, "bad ownership or modes for file %s",
421 buf);
422 return -1;
423 }
424
425 /* for each component of the canonical path, walking upwards */
426 for (;;) {
427 if ((cp = dirname(buf)) == NULL) {
428 snprintf(err, errlen, "dirname() failed");
429 return -1;
430 }
431 strlcpy(buf, cp, sizeof(buf));
432
433 debug3("secure_filename: checking '%s'", buf);
434 if (stat(buf, &st) < 0 ||
435 (st.st_uid != 0 && st.st_uid != uid) ||
436 (st.st_mode & 022) != 0) {
Damien Miller9f0f5c62001-12-21 14:45:46 +1100437 snprintf(err, errlen,
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000438 "bad ownership or modes for directory %s", buf);
439 return -1;
440 }
441
Damien Miller0ae6e002001-07-14 12:21:34 +1000442 /* If are passed the homedir then we can stop */
Ben Lindstrom485075e2002-11-09 15:45:12 +0000443 if (comparehome && strcmp(homedir, buf) == 0) {
Damien Miller0ae6e002001-07-14 12:21:34 +1000444 debug3("secure_filename: terminating check at '%s'",
445 buf);
446 break;
447 }
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000448 /*
449 * dirname should always complete with a "/" path,
450 * but we can be paranoid and check for "." too
451 */
452 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
453 break;
454 }
455 return 0;
456}
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000457
458struct passwd *
459getpwnamallow(const char *user)
460{
Ben Lindstromb481e132002-03-22 01:35:47 +0000461#ifdef HAVE_LOGIN_CAP
462 extern login_cap_t *lc;
463#ifdef BSD_AUTH
464 auth_session_t *as;
465#endif
466#endif
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000467 struct passwd *pw;
468
469 pw = getpwnam(user);
Damien Miller6f0a1882002-09-22 01:26:51 +1000470 if (pw == NULL) {
Damien Millera22f2d72004-07-21 20:48:24 +1000471 logit("Invalid user %.100s from %.100s",
Damien Miller6f0a1882002-09-22 01:26:51 +1000472 user, get_remote_ipaddr());
Darren Tucker97363a82003-05-02 23:42:25 +1000473#ifdef CUSTOM_FAILED_LOGIN
Darren Tucker42d9dc72005-02-02 17:10:11 +1100474 record_failed_login(user,
475 get_canonical_hostname(options.use_dns), "ssh");
Ben Lindstromf5397c02002-11-09 16:11:10 +0000476#endif
Darren Tucker2e0cf0d2005-02-08 21:52:47 +1100477#ifdef SSH_AUDIT_EVENTS
478 audit_event(SSH_INVALID_USER);
479#endif /* SSH_AUDIT_EVENTS */
Damien Miller6f0a1882002-09-22 01:26:51 +1000480 return (NULL);
481 }
482 if (!allowed_user(pw))
Ben Lindstromb481e132002-03-22 01:35:47 +0000483 return (NULL);
484#ifdef HAVE_LOGIN_CAP
485 if ((lc = login_getclass(pw->pw_class)) == NULL) {
486 debug("unable to get login class: %s", user);
487 return (NULL);
488 }
489#ifdef BSD_AUTH
490 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
Damien Miller13e35a02002-05-22 14:04:11 +1000491 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
Ben Lindstromb481e132002-03-22 01:35:47 +0000492 debug("Approval failure for %s", user);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000493 pw = NULL;
Ben Lindstromb481e132002-03-22 01:35:47 +0000494 }
495 if (as != NULL)
496 auth_close(as);
497#endif
498#endif
Ben Lindstromf34e4eb2002-03-22 03:08:30 +0000499 if (pw != NULL)
500 return (pwcopy(pw));
501 return (NULL);
Ben Lindstrom2ae18f42002-03-22 01:24:38 +0000502}
Ben Lindstroma574cda2002-05-15 16:16:14 +0000503
504void
505auth_debug_add(const char *fmt,...)
506{
507 char buf[1024];
508 va_list args;
509
510 if (!auth_debug_init)
511 return;
512
513 va_start(args, fmt);
514 vsnprintf(buf, sizeof(buf), fmt, args);
515 va_end(args);
516 buffer_put_cstring(&auth_debug, buf);
517}
518
519void
520auth_debug_send(void)
521{
522 char *msg;
523
524 if (!auth_debug_init)
525 return;
526 while (buffer_len(&auth_debug)) {
527 msg = buffer_get_string(&auth_debug, NULL);
528 packet_send_debug("%s", msg);
529 xfree(msg);
530 }
531}
532
533void
534auth_debug_reset(void)
535{
536 if (auth_debug_init)
537 buffer_clear(&auth_debug);
538 else {
539 buffer_init(&auth_debug);
540 auth_debug_init = 1;
541 }
542}
Damien Miller856f0be2003-09-03 07:32:45 +1000543
544struct passwd *
545fakepw(void)
546{
547 static struct passwd fake;
548
549 memset(&fake, 0, sizeof(fake));
550 fake.pw_name = "NOUSER";
551 fake.pw_passwd =
Damien Miller787b2ec2003-11-21 23:56:47 +1100552 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
Damien Miller856f0be2003-09-03 07:32:45 +1000553 fake.pw_gecos = "NOUSER";
Darren Tucker1f8311c2004-05-13 16:39:33 +1000554 fake.pw_uid = (uid_t)-1;
555 fake.pw_gid = (gid_t)-1;
Damien Miller856f0be2003-09-03 07:32:45 +1000556#ifdef HAVE_PW_CLASS_IN_PASSWD
557 fake.pw_class = "";
558#endif
559 fake.pw_dir = "/nonexist";
560 fake.pw_shell = "/nonexist";
561
562 return (&fake);
563}