djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 1 | /* $OpenBSD: auth.c,v 1.114 2016/03/07 19:02:43 djm Exp $ */ |
Damien Miller | 116e6df | 2002-05-22 15:06:28 +1000 | [diff] [blame] | 2 | /* |
Ben Lindstrom | 92a2e38 | 2001-03-05 06:59:27 +0000 | [diff] [blame] | 3 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 4 | * |
| 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 Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 24 | */ |
| 25 | |
| 26 | #include "includes.h" |
Damien Miller | f17883e | 2006-03-15 11:45:54 +1100 | [diff] [blame] | 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/stat.h> |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 30 | #include <sys/socket.h> |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 31 | |
Damien Miller | 36cbe41 | 2006-08-05 12:54:24 +1000 | [diff] [blame] | 32 | #include <netinet/in.h> |
| 33 | |
Darren Tucker | 3997249 | 2006-07-12 22:22:46 +1000 | [diff] [blame] | 34 | #include <errno.h> |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 35 | #include <fcntl.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 36 | #ifdef HAVE_PATHS_H |
Damien Miller | a9263d0 | 2006-03-15 11:18:26 +1100 | [diff] [blame] | 37 | # include <paths.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 38 | #endif |
Damien Miller | 9f2abc4 | 2006-07-10 20:53:08 +1000 | [diff] [blame] | 39 | #include <pwd.h> |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 40 | #ifdef HAVE_LOGIN_H |
| 41 | #include <login.h> |
| 42 | #endif |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 43 | #ifdef USE_SHADOW |
Damien Miller | 1f335fb | 2000-06-26 11:31:33 +1000 | [diff] [blame] | 44 | #include <shadow.h> |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 45 | #endif |
Ben Lindstrom | 68c3ce1 | 2001-06-10 17:24:51 +0000 | [diff] [blame] | 46 | #ifdef HAVE_LIBGEN_H |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 47 | #include <libgen.h> |
Ben Lindstrom | 68c3ce1 | 2001-06-10 17:24:51 +0000 | [diff] [blame] | 48 | #endif |
Darren Tucker | 5d19626 | 2006-07-12 22:15:16 +1000 | [diff] [blame] | 49 | #include <stdarg.h> |
Damien Miller | a7a73ee | 2006-08-05 11:37:59 +1000 | [diff] [blame] | 50 | #include <stdio.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 51 | #include <string.h> |
Damien Miller | 7acf550 | 2008-07-09 20:54:37 +1000 | [diff] [blame] | 52 | #include <unistd.h> |
deraadt@openbsd.org | 087266e | 2015-01-20 23:14:00 +0000 | [diff] [blame] | 53 | #include <limits.h> |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 54 | #include <netdb.h> |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 55 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 56 | #include "xmalloc.h" |
| 57 | #include "match.h" |
| 58 | #include "groupaccess.h" |
| 59 | #include "log.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 60 | #include "buffer.h" |
Damien Miller | 7acefbb | 2014-07-18 14:11:24 +1000 | [diff] [blame] | 61 | #include "misc.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 62 | #include "servconf.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 63 | #include "key.h" |
| 64 | #include "hostfile.h" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 65 | #include "auth.h" |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 66 | #include "auth-options.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 67 | #include "canohost.h" |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 68 | #include "uidswap.h" |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 69 | #include "packet.h" |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 70 | #include "loginrec.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 71 | #ifdef GSSAPI |
| 72 | #include "ssh-gss.h" |
| 73 | #endif |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 74 | #include "authfile.h" |
Darren Tucker | 269a1ea | 2005-02-03 00:20:53 +1100 | [diff] [blame] | 75 | #include "monitor_wrap.h" |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 76 | #include "authfile.h" |
| 77 | #include "ssherr.h" |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 78 | #include "compat.h" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 79 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 80 | /* import */ |
| 81 | extern ServerOptions options; |
Damien Miller | 7a8f5b3 | 2006-03-31 23:14:23 +1100 | [diff] [blame] | 82 | extern int use_privsep; |
Darren Tucker | b9aa0a0 | 2003-07-08 22:59:59 +1000 | [diff] [blame] | 83 | extern Buffer loginmsg; |
Damien Miller | 6433df0 | 2006-09-07 10:36:43 +1000 | [diff] [blame] | 84 | extern struct passwd *privsep_pw; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 85 | |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 86 | /* Debugging messages */ |
| 87 | Buffer auth_debug; |
| 88 | int auth_debug_init; |
| 89 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 90 | /* |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 91 | * Check if the user is allowed to log in via ssh. If user is listed |
| 92 | * in DenyUsers or one of user's groups is listed in DenyGroups, false |
| 93 | * will be returned. If AllowUsers isn't empty and user isn't listed |
| 94 | * there, or if AllowGroups isn't empty and one of user's groups isn't |
| 95 | * listed there, false will be returned. |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 96 | * If the user's shell is not executable, false will be returned. |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 97 | * Otherwise true is returned. |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 98 | */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 99 | int |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 100 | allowed_user(struct passwd * pw) |
| 101 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 102 | struct ssh *ssh = active_state; /* XXX */ |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 103 | struct stat st; |
Darren Tucker | 43a0dc6 | 2003-08-26 14:22:12 +1000 | [diff] [blame] | 104 | const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL; |
Damien Miller | eccb9de | 2005-06-17 12:59:34 +1000 | [diff] [blame] | 105 | u_int i; |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 106 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 107 | struct spwd *spw = NULL; |
Tim Rice | 458c6bf | 2003-01-08 20:04:27 -0800 | [diff] [blame] | 108 | #endif |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 109 | |
| 110 | /* Shouldn't be called if pw is NULL, but better safe than sorry... */ |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 111 | if (!pw || !pw->pw_name) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 112 | return 0; |
| 113 | |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 114 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 115 | if (!options.use_pam) |
| 116 | spw = getspnam(pw->pw_name); |
| 117 | #ifdef HAS_SHADOW_EXPIRE |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 118 | if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw)) |
| 119 | return 0; |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 120 | #endif /* HAS_SHADOW_EXPIRE */ |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 121 | #endif /* USE_SHADOW */ |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 122 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 123 | /* grab passwd field for locked account check */ |
Damien Miller | 22989f1 | 2008-07-05 08:59:43 +1000 | [diff] [blame] | 124 | passwd = pw->pw_passwd; |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 125 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 126 | if (spw != NULL) |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 127 | #ifdef USE_LIBIAF |
Tim Rice | 2291c00 | 2005-08-26 13:15:19 -0700 | [diff] [blame] | 128 | passwd = get_iaf_password(pw); |
| 129 | #else |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 130 | passwd = spw->sp_pwdp; |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 131 | #endif /* USE_LIBIAF */ |
Damien Miller | 06817f9 | 2003-01-07 23:55:59 +1100 | [diff] [blame] | 132 | #endif |
| 133 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 134 | /* check for locked account */ |
Darren Tucker | 43a0dc6 | 2003-08-26 14:22:12 +1000 | [diff] [blame] | 135 | if (!options.use_pam && passwd && *passwd) { |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 136 | int locked = 0; |
| 137 | |
| 138 | #ifdef LOCKED_PASSWD_STRING |
| 139 | if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0) |
| 140 | locked = 1; |
| 141 | #endif |
| 142 | #ifdef LOCKED_PASSWD_PREFIX |
| 143 | if (strncmp(passwd, LOCKED_PASSWD_PREFIX, |
| 144 | strlen(LOCKED_PASSWD_PREFIX)) == 0) |
| 145 | locked = 1; |
| 146 | #endif |
| 147 | #ifdef LOCKED_PASSWD_SUBSTR |
| 148 | if (strstr(passwd, LOCKED_PASSWD_SUBSTR)) |
| 149 | locked = 1; |
| 150 | #endif |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 151 | #ifdef USE_LIBIAF |
Tim Rice | ad7d547 | 2010-08-12 10:33:01 -0700 | [diff] [blame] | 152 | free((void *) passwd); |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 153 | #endif /* USE_LIBIAF */ |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 154 | if (locked) { |
| 155 | logit("User %.100s not allowed because account is locked", |
| 156 | pw->pw_name); |
| 157 | return 0; |
| 158 | } |
| 159 | } |
| 160 | |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 161 | /* |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 162 | * Deny if shell does not exist or is not executable unless we |
| 163 | * are chrooting. |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 164 | */ |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 165 | if (options.chroot_directory == NULL || |
| 166 | strcasecmp(options.chroot_directory, "none") == 0) { |
| 167 | char *shell = xstrdup((pw->pw_shell[0] == '\0') ? |
| 168 | _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ |
Darren Tucker | 94881d8 | 2010-01-15 11:44:46 +1100 | [diff] [blame] | 169 | |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 170 | if (stat(shell, &st) != 0) { |
| 171 | logit("User %.100s not allowed because shell %.100s " |
| 172 | "does not exist", pw->pw_name, shell); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 173 | free(shell); |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 174 | return 0; |
| 175 | } |
| 176 | if (S_ISREG(st.st_mode) == 0 || |
| 177 | (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { |
| 178 | logit("User %.100s not allowed because shell %.100s " |
| 179 | "is not executable", pw->pw_name, shell); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 180 | free(shell); |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 181 | return 0; |
| 182 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 183 | free(shell); |
Darren Tucker | 94881d8 | 2010-01-15 11:44:46 +1100 | [diff] [blame] | 184 | } |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 185 | |
Darren Tucker | a8f553d | 2005-03-14 23:17:27 +1100 | [diff] [blame] | 186 | if (options.num_deny_users > 0 || options.num_allow_users > 0 || |
| 187 | options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 188 | hostname = auth_get_canonical_hostname(ssh, options.use_dns); |
| 189 | ipaddr = ssh_remote_ipaddr(ssh); |
Ben Lindstrom | 3fb5d00 | 2002-03-05 01:42:42 +0000 | [diff] [blame] | 190 | } |
| 191 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 192 | /* Return false if user is listed in DenyUsers */ |
| 193 | if (options.num_deny_users > 0) { |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 194 | for (i = 0; i < options.num_deny_users; i++) |
Ben Lindstrom | 6328ab3 | 2002-03-22 02:54:23 +0000 | [diff] [blame] | 195 | if (match_user(pw->pw_name, hostname, ipaddr, |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 196 | options.deny_users[i])) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 197 | logit("User %.100s from %.100s not allowed " |
| 198 | "because listed in DenyUsers", |
| 199 | pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 200 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 201 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 202 | } |
| 203 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
| 204 | if (options.num_allow_users > 0) { |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 205 | for (i = 0; i < options.num_allow_users; i++) |
Ben Lindstrom | 6328ab3 | 2002-03-22 02:54:23 +0000 | [diff] [blame] | 206 | if (match_user(pw->pw_name, hostname, ipaddr, |
Ben Lindstrom | 6026002 | 2001-07-04 04:56:44 +0000 | [diff] [blame] | 207 | options.allow_users[i])) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 208 | break; |
| 209 | /* i < options.num_allow_users iff we break for loop */ |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 210 | if (i >= options.num_allow_users) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 211 | logit("User %.100s from %.100s not allowed because " |
| 212 | "not listed in AllowUsers", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 213 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 214 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 215 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 216 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 217 | /* Get the user's group access list (primary and supplementary) */ |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 218 | if (ga_init(pw->pw_name, pw->pw_gid) == 0) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 219 | logit("User %.100s from %.100s not allowed because " |
| 220 | "not in any group", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 221 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 222 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 223 | |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 224 | /* Return false if one of user's groups is listed in DenyGroups */ |
| 225 | if (options.num_deny_groups > 0) |
| 226 | if (ga_match(options.deny_groups, |
| 227 | options.num_deny_groups)) { |
| 228 | ga_free(); |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 229 | logit("User %.100s from %.100s not allowed " |
| 230 | "because a group is listed in DenyGroups", |
| 231 | pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 232 | return 0; |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 233 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 234 | /* |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 235 | * Return false if AllowGroups isn't empty and one of user's groups |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 236 | * isn't listed there |
| 237 | */ |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 238 | if (options.num_allow_groups > 0) |
| 239 | if (!ga_match(options.allow_groups, |
| 240 | options.num_allow_groups)) { |
| 241 | ga_free(); |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 242 | logit("User %.100s from %.100s not allowed " |
| 243 | "because none of user's groups are listed " |
| 244 | "in AllowGroups", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 245 | return 0; |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 246 | } |
| 247 | ga_free(); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 248 | } |
| 249 | |
Darren Tucker | 0a9d43d | 2004-06-23 13:45:24 +1000 | [diff] [blame] | 250 | #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER |
Darren Tucker | 691d523 | 2005-02-15 21:45:57 +1100 | [diff] [blame] | 251 | if (!sys_auth_allowed_user(pw, &loginmsg)) |
Darren Tucker | 0a9d43d | 2004-06-23 13:45:24 +1000 | [diff] [blame] | 252 | return 0; |
| 253 | #endif |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 254 | |
| 255 | /* We found no reason not to let this user try to log on... */ |
| 256 | return 1; |
| 257 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 258 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 259 | void |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 260 | auth_info(Authctxt *authctxt, const char *fmt, ...) |
| 261 | { |
| 262 | va_list ap; |
| 263 | int i; |
| 264 | |
| 265 | free(authctxt->info); |
| 266 | authctxt->info = NULL; |
| 267 | |
| 268 | va_start(ap, fmt); |
| 269 | i = vasprintf(&authctxt->info, fmt, ap); |
| 270 | va_end(ap); |
| 271 | |
| 272 | if (i < 0 || authctxt->info == NULL) |
| 273 | fatal("vasprintf failed"); |
| 274 | } |
| 275 | |
| 276 | void |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 277 | auth_log(Authctxt *authctxt, int authenticated, int partial, |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 278 | const char *method, const char *submethod) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 279 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 280 | struct ssh *ssh = active_state; /* XXX */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 281 | void (*authlog) (const char *fmt,...) = verbose; |
| 282 | char *authmsg; |
| 283 | |
Damien Miller | 7a8f5b3 | 2006-03-31 23:14:23 +1100 | [diff] [blame] | 284 | if (use_privsep && !mm_is_monitor() && !authctxt->postponed) |
| 285 | return; |
| 286 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 287 | /* Raise logging level */ |
| 288 | if (authenticated == 1 || |
| 289 | !authctxt->valid || |
Darren Tucker | 89413db | 2004-05-24 10:36:23 +1000 | [diff] [blame] | 290 | authctxt->failures >= options.max_authtries / 2 || |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 291 | strcmp(method, "password") == 0) |
Damien Miller | 2a3f20e | 2003-04-09 21:12:00 +1000 | [diff] [blame] | 292 | authlog = logit; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 293 | |
| 294 | if (authctxt->postponed) |
| 295 | authmsg = "Postponed"; |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 296 | else if (partial) |
| 297 | authmsg = "Partial"; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 298 | else |
| 299 | authmsg = authenticated ? "Accepted" : "Failed"; |
| 300 | |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 301 | authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s", |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 302 | authmsg, |
| 303 | method, |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 304 | submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 305 | authctxt->valid ? "" : "invalid user ", |
Damien Miller | f655207 | 2001-11-12 11:06:06 +1100 | [diff] [blame] | 306 | authctxt->user, |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 307 | ssh_remote_ipaddr(ssh), |
| 308 | ssh_remote_port(ssh), |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 309 | compat20 ? "ssh2" : "ssh1", |
| 310 | authctxt->info != NULL ? ": " : "", |
| 311 | authctxt->info != NULL ? authctxt->info : ""); |
| 312 | free(authctxt->info); |
| 313 | authctxt->info = NULL; |
Ben Lindstrom | e06eb68 | 2002-07-04 00:27:21 +0000 | [diff] [blame] | 314 | |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 315 | #ifdef CUSTOM_FAILED_LOGIN |
Darren Tucker | 2fba993 | 2005-02-02 23:30:24 +1100 | [diff] [blame] | 316 | if (authenticated == 0 && !authctxt->postponed && |
| 317 | (strcmp(method, "password") == 0 || |
Darren Tucker | 40d9a63 | 2005-02-04 15:19:44 +1100 | [diff] [blame] | 318 | strncmp(method, "keyboard-interactive", 20) == 0 || |
| 319 | strcmp(method, "challenge-response") == 0)) |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 320 | record_failed_login(authctxt->user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 321 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); |
Darren Tucker | 26d4e19 | 2006-08-30 22:33:09 +1000 | [diff] [blame] | 322 | # ifdef WITH_AIXAUTHENTICATE |
| 323 | if (authenticated) |
| 324 | sys_auth_record_login(authctxt->user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 325 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh", |
| 326 | &loginmsg); |
Darren Tucker | 26d4e19 | 2006-08-30 22:33:09 +1000 | [diff] [blame] | 327 | # endif |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 328 | #endif |
Darren Tucker | 2e0cf0d | 2005-02-08 21:52:47 +1100 | [diff] [blame] | 329 | #ifdef SSH_AUDIT_EVENTS |
Darren Tucker | f14b2aa | 2006-05-21 18:26:40 +1000 | [diff] [blame] | 330 | if (authenticated == 0 && !authctxt->postponed) |
| 331 | audit_event(audit_classify_auth(method)); |
Darren Tucker | 269a1ea | 2005-02-03 00:20:53 +1100 | [diff] [blame] | 332 | #endif |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 333 | } |
| 334 | |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 335 | |
| 336 | void |
| 337 | auth_maxtries_exceeded(Authctxt *authctxt) |
| 338 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 339 | struct ssh *ssh = active_state; /* XXX */ |
| 340 | |
djm@openbsd.org | 6f62160 | 2015-02-25 17:29:38 +0000 | [diff] [blame] | 341 | error("maximum authentication attempts exceeded for " |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 342 | "%s%.100s from %.200s port %d %s", |
| 343 | authctxt->valid ? "" : "invalid user ", |
| 344 | authctxt->user, |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 345 | ssh_remote_ipaddr(ssh), |
| 346 | ssh_remote_port(ssh), |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 347 | compat20 ? "ssh2" : "ssh1"); |
djm@openbsd.org | 6f62160 | 2015-02-25 17:29:38 +0000 | [diff] [blame] | 348 | packet_disconnect("Too many authentication failures"); |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 349 | /* NOTREACHED */ |
| 350 | } |
| 351 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 352 | /* |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 353 | * Check whether root logins are disallowed. |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 354 | */ |
| 355 | int |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 356 | auth_root_allowed(const char *method) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 357 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 358 | struct ssh *ssh = active_state; /* XXX */ |
| 359 | |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 360 | switch (options.permit_root_login) { |
| 361 | case PERMIT_YES: |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 362 | return 1; |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 363 | case PERMIT_NO_PASSWD: |
deraadt@openbsd.org | 1dc8d93 | 2015-08-06 14:53:21 +0000 | [diff] [blame] | 364 | if (strcmp(method, "publickey") == 0 || |
| 365 | strcmp(method, "hostbased") == 0 || |
djm@openbsd.org | 32a1819 | 2015-08-21 03:42:19 +0000 | [diff] [blame] | 366 | strcmp(method, "gssapi-with-mic") == 0) |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 367 | return 1; |
| 368 | break; |
| 369 | case PERMIT_FORCED_ONLY: |
| 370 | if (forced_command) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 371 | logit("Root login accepted for forced command."); |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 372 | return 1; |
| 373 | } |
| 374 | break; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 375 | } |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 376 | logit("ROOT LOGIN REFUSED FROM %.200s port %d", |
| 377 | ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 378 | return 0; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 379 | } |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 380 | |
| 381 | |
| 382 | /* |
| 383 | * Given a template and a passwd structure, build a filename |
| 384 | * by substituting % tokenised options. Currently, %% becomes '%', |
| 385 | * %h becomes the home directory and %u the username. |
| 386 | * |
| 387 | * This returns a buffer allocated by xmalloc. |
| 388 | */ |
Damien Miller | d8478b6 | 2011-05-29 21:39:36 +1000 | [diff] [blame] | 389 | char * |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 390 | expand_authorized_keys(const char *filename, struct passwd *pw) |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 391 | { |
deraadt@openbsd.org | 087266e | 2015-01-20 23:14:00 +0000 | [diff] [blame] | 392 | char *file, ret[PATH_MAX]; |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 393 | int i; |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 394 | |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 395 | file = percent_expand(filename, "h", pw->pw_dir, |
| 396 | "u", pw->pw_name, (char *)NULL); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 397 | |
| 398 | /* |
| 399 | * Ensure that filename starts anchored. If not, be backward |
| 400 | * compatible and prepend the '%h/' |
| 401 | */ |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 402 | if (*file == '/') |
| 403 | return (file); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 404 | |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 405 | i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); |
| 406 | if (i < 0 || (size_t)i >= sizeof(ret)) |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 407 | fatal("expand_authorized_keys: path too long"); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 408 | free(file); |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 409 | return (xstrdup(ret)); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 410 | } |
| 411 | |
| 412 | char * |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 413 | authorized_principals_file(struct passwd *pw) |
| 414 | { |
djm@openbsd.org | 7e8528c | 2015-05-01 04:17:51 +0000 | [diff] [blame] | 415 | if (options.authorized_principals_file == NULL) |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 416 | return NULL; |
| 417 | return expand_authorized_keys(options.authorized_principals_file, pw); |
| 418 | } |
| 419 | |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 420 | /* return ok if key exists in sysfile or userfile */ |
| 421 | HostStatus |
| 422 | check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, |
| 423 | const char *sysfile, const char *userfile) |
| 424 | { |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 425 | char *user_hostfile; |
| 426 | struct stat st; |
Ben Lindstrom | 65366a8 | 2001-12-06 16:32:47 +0000 | [diff] [blame] | 427 | HostStatus host_status; |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 428 | struct hostkeys *hostkeys; |
| 429 | const struct hostkey_entry *found; |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 430 | |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 431 | hostkeys = init_hostkeys(); |
| 432 | load_hostkeys(hostkeys, host, sysfile); |
| 433 | if (userfile != NULL) { |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 434 | user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); |
| 435 | if (options.strict_modes && |
| 436 | (stat(user_hostfile, &st) == 0) && |
| 437 | ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 438 | (st.st_mode & 022) != 0)) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 439 | logit("Authentication refused for %.100s: " |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 440 | "bad owner or modes for %.200s", |
| 441 | pw->pw_name, user_hostfile); |
Damien Miller | 48147d6 | 2010-06-26 09:39:25 +1000 | [diff] [blame] | 442 | auth_debug_add("Ignored %.200s: bad ownership or modes", |
| 443 | user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 444 | } else { |
| 445 | temporarily_use_uid(pw); |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 446 | load_hostkeys(hostkeys, host, user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 447 | restore_uid(); |
| 448 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 449 | free(user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 450 | } |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 451 | host_status = check_key_in_hostkeys(hostkeys, key, &found); |
| 452 | if (host_status == HOST_REVOKED) |
| 453 | error("WARNING: revoked key for %s attempted authentication", |
| 454 | found->host); |
| 455 | else if (host_status == HOST_OK) |
| 456 | debug("%s: key for %s found at %s:%ld", __func__, |
| 457 | found->host, found->file, found->line); |
| 458 | else |
| 459 | debug("%s: key for host %s not found", __func__, host); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 460 | |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 461 | free_hostkeys(hostkeys); |
| 462 | |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 463 | return host_status; |
| 464 | } |
| 465 | |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 466 | /* |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 467 | * Check a given path for security. This is defined as all components |
Ben Lindstrom | d4ee349 | 2002-08-20 18:42:13 +0000 | [diff] [blame] | 468 | * of the path to the file must be owned by either the owner of |
Ben Lindstrom | 60567ff | 2001-06-05 20:27:53 +0000 | [diff] [blame] | 469 | * of the file or root and no directories must be group or world writable. |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 470 | * |
| 471 | * XXX Should any specific check be done for sym links ? |
| 472 | * |
Damien Miller | 18de913 | 2013-02-12 11:02:27 +1100 | [diff] [blame] | 473 | * Takes a file name, its stat information (preferably from fstat() to |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 474 | * avoid races), the uid of the expected owner, their home directory and an |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 475 | * error buffer plus max size as arguments. |
| 476 | * |
| 477 | * Returns 0 on success and -1 on failure |
| 478 | */ |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 479 | int |
| 480 | auth_secure_path(const char *name, struct stat *stp, const char *pw_dir, |
| 481 | uid_t uid, char *err, size_t errlen) |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 482 | { |
deraadt@openbsd.org | 087266e | 2015-01-20 23:14:00 +0000 | [diff] [blame] | 483 | char buf[PATH_MAX], homedir[PATH_MAX]; |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 484 | char *cp; |
Ben Lindstrom | 485075e | 2002-11-09 15:45:12 +0000 | [diff] [blame] | 485 | int comparehome = 0; |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 486 | struct stat st; |
| 487 | |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 488 | if (realpath(name, buf) == NULL) { |
| 489 | snprintf(err, errlen, "realpath %s failed: %s", name, |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 490 | strerror(errno)); |
| 491 | return -1; |
| 492 | } |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 493 | if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL) |
Ben Lindstrom | 485075e | 2002-11-09 15:45:12 +0000 | [diff] [blame] | 494 | comparehome = 1; |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 495 | |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 496 | if (!S_ISREG(stp->st_mode)) { |
| 497 | snprintf(err, errlen, "%s is not a regular file", buf); |
| 498 | return -1; |
| 499 | } |
Darren Tucker | aa97d13 | 2013-03-12 11:31:05 +1100 | [diff] [blame] | 500 | if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) || |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 501 | (stp->st_mode & 022) != 0) { |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 502 | snprintf(err, errlen, "bad ownership or modes for file %s", |
| 503 | buf); |
| 504 | return -1; |
| 505 | } |
| 506 | |
| 507 | /* for each component of the canonical path, walking upwards */ |
| 508 | for (;;) { |
| 509 | if ((cp = dirname(buf)) == NULL) { |
| 510 | snprintf(err, errlen, "dirname() failed"); |
| 511 | return -1; |
| 512 | } |
| 513 | strlcpy(buf, cp, sizeof(buf)); |
| 514 | |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 515 | if (stat(buf, &st) < 0 || |
Darren Tucker | aa97d13 | 2013-03-12 11:31:05 +1100 | [diff] [blame] | 516 | (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) || |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 517 | (st.st_mode & 022) != 0) { |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 518 | snprintf(err, errlen, |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 519 | "bad ownership or modes for directory %s", buf); |
| 520 | return -1; |
| 521 | } |
| 522 | |
Darren Tucker | e2b3674 | 2010-01-13 22:42:34 +1100 | [diff] [blame] | 523 | /* If are past the homedir then we can stop */ |
Damien Miller | 1dd66e5 | 2011-05-29 21:40:42 +1000 | [diff] [blame] | 524 | if (comparehome && strcmp(homedir, buf) == 0) |
Damien Miller | 0ae6e00 | 2001-07-14 12:21:34 +1000 | [diff] [blame] | 525 | break; |
Damien Miller | 1dd66e5 | 2011-05-29 21:40:42 +1000 | [diff] [blame] | 526 | |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 527 | /* |
| 528 | * dirname should always complete with a "/" path, |
| 529 | * but we can be paranoid and check for "." too |
| 530 | */ |
| 531 | if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0)) |
| 532 | break; |
| 533 | } |
| 534 | return 0; |
| 535 | } |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 536 | |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 537 | /* |
| 538 | * Version of secure_path() that accepts an open file descriptor to |
| 539 | * avoid races. |
| 540 | * |
| 541 | * Returns 0 on success and -1 on failure |
| 542 | */ |
| 543 | static int |
| 544 | secure_filename(FILE *f, const char *file, struct passwd *pw, |
| 545 | char *err, size_t errlen) |
| 546 | { |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 547 | struct stat st; |
| 548 | |
| 549 | /* check the open file to avoid races */ |
| 550 | if (fstat(fileno(f), &st) < 0) { |
| 551 | snprintf(err, errlen, "cannot stat file %s: %s", |
Damien Miller | 4e14a58 | 2013-01-09 15:54:48 +1100 | [diff] [blame] | 552 | file, strerror(errno)); |
Damien Miller | 09d3e12 | 2012-10-31 08:58:58 +1100 | [diff] [blame] | 553 | return -1; |
| 554 | } |
| 555 | return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen); |
| 556 | } |
| 557 | |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 558 | static FILE * |
| 559 | auth_openfile(const char *file, struct passwd *pw, int strict_modes, |
| 560 | int log_missing, char *file_type) |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 561 | { |
| 562 | char line[1024]; |
| 563 | struct stat st; |
| 564 | int fd; |
| 565 | FILE *f; |
| 566 | |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 567 | if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) { |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 568 | if (log_missing || errno != ENOENT) |
| 569 | debug("Could not open %s '%s': %s", file_type, file, |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 570 | strerror(errno)); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 571 | return NULL; |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 572 | } |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 573 | |
| 574 | if (fstat(fd, &st) < 0) { |
| 575 | close(fd); |
| 576 | return NULL; |
| 577 | } |
| 578 | if (!S_ISREG(st.st_mode)) { |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 579 | logit("User %s %s %s is not a regular file", |
| 580 | pw->pw_name, file_type, file); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 581 | close(fd); |
| 582 | return NULL; |
| 583 | } |
| 584 | unset_nonblock(fd); |
| 585 | if ((f = fdopen(fd, "r")) == NULL) { |
| 586 | close(fd); |
| 587 | return NULL; |
| 588 | } |
Damien Miller | 6a740e7 | 2010-12-01 12:01:51 +1100 | [diff] [blame] | 589 | if (strict_modes && |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 590 | secure_filename(f, file, pw, line, sizeof(line)) != 0) { |
| 591 | fclose(f); |
| 592 | logit("Authentication refused: %s", line); |
Damien Miller | 48147d6 | 2010-06-26 09:39:25 +1000 | [diff] [blame] | 593 | auth_debug_add("Ignored %s: %s", file_type, line); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 594 | return NULL; |
| 595 | } |
| 596 | |
| 597 | return f; |
| 598 | } |
| 599 | |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 600 | |
| 601 | FILE * |
| 602 | auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes) |
| 603 | { |
| 604 | return auth_openfile(file, pw, strict_modes, 1, "authorized keys"); |
| 605 | } |
| 606 | |
| 607 | FILE * |
| 608 | auth_openprincipals(const char *file, struct passwd *pw, int strict_modes) |
| 609 | { |
| 610 | return auth_openfile(file, pw, strict_modes, 0, |
| 611 | "authorized principals"); |
| 612 | } |
| 613 | |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 614 | struct passwd * |
| 615 | getpwnamallow(const char *user) |
| 616 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 617 | struct ssh *ssh = active_state; /* XXX */ |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 618 | #ifdef HAVE_LOGIN_CAP |
| 619 | extern login_cap_t *lc; |
| 620 | #ifdef BSD_AUTH |
| 621 | auth_session_t *as; |
| 622 | #endif |
| 623 | #endif |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 624 | struct passwd *pw; |
Darren Tucker | fbcf827 | 2012-05-19 19:37:01 +1000 | [diff] [blame] | 625 | struct connection_info *ci = get_connection_info(1, options.use_dns); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 626 | |
Darren Tucker | fbcf827 | 2012-05-19 19:37:01 +1000 | [diff] [blame] | 627 | ci->user = user; |
| 628 | parse_server_match_config(&options, ci); |
Darren Tucker | 4515047 | 2006-07-12 22:34:17 +1000 | [diff] [blame] | 629 | |
Darren Tucker | b3d20a3 | 2010-03-07 11:56:59 +1100 | [diff] [blame] | 630 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 631 | aix_setauthdb(user); |
| 632 | #endif |
| 633 | |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 634 | pw = getpwnam(user); |
Darren Tucker | b3d20a3 | 2010-03-07 11:56:59 +1100 | [diff] [blame] | 635 | |
| 636 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 637 | aix_restoreauthdb(); |
| 638 | #endif |
Damien Miller | acc9b29 | 2010-03-01 04:36:54 +1100 | [diff] [blame] | 639 | #ifdef HAVE_CYGWIN |
| 640 | /* |
| 641 | * Windows usernames are case-insensitive. To avoid later problems |
| 642 | * when trying to match the username, the user is only allowed to |
| 643 | * login if the username is given in the same case as stored in the |
| 644 | * user database. |
| 645 | */ |
| 646 | if (pw != NULL && strcmp(user, pw->pw_name) != 0) { |
| 647 | logit("Login name %.100s does not match stored username %.100s", |
| 648 | user, pw->pw_name); |
| 649 | pw = NULL; |
| 650 | } |
| 651 | #endif |
Damien Miller | 6f0a188 | 2002-09-22 01:26:51 +1000 | [diff] [blame] | 652 | if (pw == NULL) { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 653 | logit("Invalid user %.100s from %.100s port %d", |
| 654 | user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 655 | #ifdef CUSTOM_FAILED_LOGIN |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 656 | record_failed_login(user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 657 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); |
Ben Lindstrom | f5397c0 | 2002-11-09 16:11:10 +0000 | [diff] [blame] | 658 | #endif |
Darren Tucker | 2e0cf0d | 2005-02-08 21:52:47 +1100 | [diff] [blame] | 659 | #ifdef SSH_AUDIT_EVENTS |
| 660 | audit_event(SSH_INVALID_USER); |
| 661 | #endif /* SSH_AUDIT_EVENTS */ |
Damien Miller | 6f0a188 | 2002-09-22 01:26:51 +1000 | [diff] [blame] | 662 | return (NULL); |
| 663 | } |
| 664 | if (!allowed_user(pw)) |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 665 | return (NULL); |
| 666 | #ifdef HAVE_LOGIN_CAP |
| 667 | if ((lc = login_getclass(pw->pw_class)) == NULL) { |
| 668 | debug("unable to get login class: %s", user); |
| 669 | return (NULL); |
| 670 | } |
| 671 | #ifdef BSD_AUTH |
| 672 | if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || |
Damien Miller | 13e35a0 | 2002-05-22 14:04:11 +1000 | [diff] [blame] | 673 | auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 674 | debug("Approval failure for %s", user); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 675 | pw = NULL; |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 676 | } |
| 677 | if (as != NULL) |
| 678 | auth_close(as); |
| 679 | #endif |
| 680 | #endif |
Ben Lindstrom | f34e4eb | 2002-03-22 03:08:30 +0000 | [diff] [blame] | 681 | if (pw != NULL) |
| 682 | return (pwcopy(pw)); |
| 683 | return (NULL); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 684 | } |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 685 | |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 686 | /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ |
| 687 | int |
| 688 | auth_key_is_revoked(Key *key) |
| 689 | { |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 690 | char *fp = NULL; |
| 691 | int r; |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 692 | |
| 693 | if (options.revoked_keys_file == NULL) |
| 694 | return 0; |
djm@openbsd.org | 56d1c83 | 2014-12-21 22:27:55 +0000 | [diff] [blame] | 695 | if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| 696 | SSH_FP_DEFAULT)) == NULL) { |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 697 | r = SSH_ERR_ALLOC_FAIL; |
| 698 | error("%s: fingerprint key: %s", __func__, ssh_err(r)); |
| 699 | goto out; |
| 700 | } |
| 701 | |
| 702 | r = sshkey_check_revoked(key, options.revoked_keys_file); |
| 703 | switch (r) { |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 704 | case 0: |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 705 | break; /* not revoked */ |
| 706 | case SSH_ERR_KEY_REVOKED: |
| 707 | error("Authentication key %s %s revoked by file %s", |
| 708 | sshkey_type(key), fp, options.revoked_keys_file); |
| 709 | goto out; |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 710 | default: |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 711 | error("Error checking authentication key %s %s in " |
| 712 | "revoked keys file %s: %s", sshkey_type(key), fp, |
| 713 | options.revoked_keys_file, ssh_err(r)); |
| 714 | goto out; |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 715 | } |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 716 | |
| 717 | /* Success */ |
| 718 | r = 0; |
| 719 | |
| 720 | out: |
| 721 | free(fp); |
| 722 | return r == 0 ? 0 : 1; |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 723 | } |
| 724 | |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 725 | void |
| 726 | auth_debug_add(const char *fmt,...) |
| 727 | { |
| 728 | char buf[1024]; |
| 729 | va_list args; |
| 730 | |
| 731 | if (!auth_debug_init) |
| 732 | return; |
| 733 | |
| 734 | va_start(args, fmt); |
| 735 | vsnprintf(buf, sizeof(buf), fmt, args); |
| 736 | va_end(args); |
| 737 | buffer_put_cstring(&auth_debug, buf); |
| 738 | } |
| 739 | |
| 740 | void |
| 741 | auth_debug_send(void) |
| 742 | { |
| 743 | char *msg; |
| 744 | |
| 745 | if (!auth_debug_init) |
| 746 | return; |
| 747 | while (buffer_len(&auth_debug)) { |
| 748 | msg = buffer_get_string(&auth_debug, NULL); |
| 749 | packet_send_debug("%s", msg); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 750 | free(msg); |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 751 | } |
| 752 | } |
| 753 | |
| 754 | void |
| 755 | auth_debug_reset(void) |
| 756 | { |
| 757 | if (auth_debug_init) |
| 758 | buffer_clear(&auth_debug); |
| 759 | else { |
| 760 | buffer_init(&auth_debug); |
| 761 | auth_debug_init = 1; |
| 762 | } |
| 763 | } |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 764 | |
| 765 | struct passwd * |
| 766 | fakepw(void) |
| 767 | { |
| 768 | static struct passwd fake; |
| 769 | |
| 770 | memset(&fake, 0, sizeof(fake)); |
| 771 | fake.pw_name = "NOUSER"; |
| 772 | fake.pw_passwd = |
Damien Miller | 787b2ec | 2003-11-21 23:56:47 +1100 | [diff] [blame] | 773 | "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK"; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 774 | #ifdef HAVE_STRUCT_PASSWD_PW_GECOS |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 775 | fake.pw_gecos = "NOUSER"; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 776 | #endif |
Damien Miller | 143c2ef | 2006-12-05 09:08:54 +1100 | [diff] [blame] | 777 | fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid; |
| 778 | fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 779 | #ifdef HAVE_STRUCT_PASSWD_PW_CLASS |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 780 | fake.pw_class = ""; |
| 781 | #endif |
| 782 | fake.pw_dir = "/nonexist"; |
| 783 | fake.pw_shell = "/nonexist"; |
| 784 | |
| 785 | return (&fake); |
| 786 | } |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 787 | |
| 788 | /* |
| 789 | * Returns the remote DNS hostname as a string. The returned string must not |
| 790 | * be freed. NB. this will usually trigger a DNS query the first time it is |
| 791 | * called. |
| 792 | * This function does additional checks on the hostname to mitigate some |
| 793 | * attacks on legacy rhosts-style authentication. |
| 794 | * XXX is RhostsRSAAuthentication vulnerable to these? |
| 795 | * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?) |
| 796 | */ |
| 797 | |
| 798 | static char * |
| 799 | remote_hostname(struct ssh *ssh) |
| 800 | { |
| 801 | struct sockaddr_storage from; |
| 802 | socklen_t fromlen; |
| 803 | struct addrinfo hints, *ai, *aitop; |
| 804 | char name[NI_MAXHOST], ntop2[NI_MAXHOST]; |
| 805 | const char *ntop = ssh_remote_ipaddr(ssh); |
| 806 | |
| 807 | /* Get IP address of client. */ |
| 808 | fromlen = sizeof(from); |
| 809 | memset(&from, 0, sizeof(from)); |
| 810 | if (getpeername(ssh_packet_get_connection_in(ssh), |
| 811 | (struct sockaddr *)&from, &fromlen) < 0) { |
| 812 | debug("getpeername failed: %.100s", strerror(errno)); |
| 813 | return strdup(ntop); |
| 814 | } |
| 815 | |
| 816 | ipv64_normalise_mapped(&from, &fromlen); |
| 817 | if (from.ss_family == AF_INET6) |
| 818 | fromlen = sizeof(struct sockaddr_in6); |
| 819 | |
| 820 | debug3("Trying to reverse map address %.100s.", ntop); |
| 821 | /* Map the IP address to a host name. */ |
| 822 | if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), |
| 823 | NULL, 0, NI_NAMEREQD) != 0) { |
| 824 | /* Host name not found. Use ip address. */ |
| 825 | return strdup(ntop); |
| 826 | } |
| 827 | |
| 828 | /* |
| 829 | * if reverse lookup result looks like a numeric hostname, |
| 830 | * someone is trying to trick us by PTR record like following: |
| 831 | * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 |
| 832 | */ |
| 833 | memset(&hints, 0, sizeof(hints)); |
| 834 | hints.ai_socktype = SOCK_DGRAM; /*dummy*/ |
| 835 | hints.ai_flags = AI_NUMERICHOST; |
| 836 | if (getaddrinfo(name, NULL, &hints, &ai) == 0) { |
| 837 | logit("Nasty PTR record \"%s\" is set up for %s, ignoring", |
| 838 | name, ntop); |
| 839 | freeaddrinfo(ai); |
| 840 | return strdup(ntop); |
| 841 | } |
| 842 | |
| 843 | /* Names are stored in lowercase. */ |
| 844 | lowercase(name); |
| 845 | |
| 846 | /* |
| 847 | * Map it back to an IP address and check that the given |
| 848 | * address actually is an address of this host. This is |
| 849 | * necessary because anyone with access to a name server can |
| 850 | * define arbitrary names for an IP address. Mapping from |
| 851 | * name to IP address can be trusted better (but can still be |
| 852 | * fooled if the intruder has access to the name server of |
| 853 | * the domain). |
| 854 | */ |
| 855 | memset(&hints, 0, sizeof(hints)); |
| 856 | hints.ai_family = from.ss_family; |
| 857 | hints.ai_socktype = SOCK_STREAM; |
| 858 | if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { |
| 859 | logit("reverse mapping checking getaddrinfo for %.700s " |
| 860 | "[%s] failed - POSSIBLE BREAK-IN ATTEMPT!", name, ntop); |
| 861 | return strdup(ntop); |
| 862 | } |
| 863 | /* Look for the address from the list of addresses. */ |
| 864 | for (ai = aitop; ai; ai = ai->ai_next) { |
| 865 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, |
| 866 | sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && |
| 867 | (strcmp(ntop, ntop2) == 0)) |
| 868 | break; |
| 869 | } |
| 870 | freeaddrinfo(aitop); |
| 871 | /* If we reached the end of the list, the address was not there. */ |
| 872 | if (ai == NULL) { |
| 873 | /* Address not found for the host name. */ |
| 874 | logit("Address %.100s maps to %.600s, but this does not " |
| 875 | "map back to the address - POSSIBLE BREAK-IN ATTEMPT!", |
| 876 | ntop, name); |
| 877 | return strdup(ntop); |
| 878 | } |
| 879 | return strdup(name); |
| 880 | } |
| 881 | |
| 882 | /* |
| 883 | * Return the canonical name of the host in the other side of the current |
| 884 | * connection. The host name is cached, so it is efficient to call this |
| 885 | * several times. |
| 886 | */ |
| 887 | |
| 888 | const char * |
| 889 | auth_get_canonical_hostname(struct ssh *ssh, int use_dns) |
| 890 | { |
| 891 | static char *dnsname; |
| 892 | |
| 893 | if (!use_dns) |
| 894 | return ssh_remote_ipaddr(ssh); |
| 895 | else if (dnsname != NULL) |
| 896 | return dnsname; |
| 897 | else { |
| 898 | dnsname = remote_hostname(ssh); |
| 899 | return dnsname; |
| 900 | } |
| 901 | } |