djm@openbsd.org | 93c06ab | 2018-06-06 18:23:32 +0000 | [diff] [blame] | 1 | /* $OpenBSD: auth.c,v 1.130 2018/06/06 18:23:32 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> |
markus@openbsd.org | 25cf910 | 2018-01-08 15:21:49 +0000 | [diff] [blame] | 31 | #include <sys/wait.h> |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 32 | |
Damien Miller | 36cbe41 | 2006-08-05 12:54:24 +1000 | [diff] [blame] | 33 | #include <netinet/in.h> |
| 34 | |
Darren Tucker | 3997249 | 2006-07-12 22:22:46 +1000 | [diff] [blame] | 35 | #include <errno.h> |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 36 | #include <fcntl.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 37 | #ifdef HAVE_PATHS_H |
Damien Miller | a9263d0 | 2006-03-15 11:18:26 +1100 | [diff] [blame] | 38 | # include <paths.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 39 | #endif |
Damien Miller | 9f2abc4 | 2006-07-10 20:53:08 +1000 | [diff] [blame] | 40 | #include <pwd.h> |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 41 | #ifdef HAVE_LOGIN_H |
| 42 | #include <login.h> |
| 43 | #endif |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 44 | #ifdef USE_SHADOW |
Damien Miller | 1f335fb | 2000-06-26 11:31:33 +1000 | [diff] [blame] | 45 | #include <shadow.h> |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 46 | #endif |
Darren Tucker | 5d19626 | 2006-07-12 22:15:16 +1000 | [diff] [blame] | 47 | #include <stdarg.h> |
Damien Miller | a7a73ee | 2006-08-05 11:37:59 +1000 | [diff] [blame] | 48 | #include <stdio.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 49 | #include <string.h> |
Damien Miller | 7acf550 | 2008-07-09 20:54:37 +1000 | [diff] [blame] | 50 | #include <unistd.h> |
deraadt@openbsd.org | 087266e | 2015-01-20 23:14:00 +0000 | [diff] [blame] | 51 | #include <limits.h> |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 52 | #include <netdb.h> |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 53 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 54 | #include "xmalloc.h" |
| 55 | #include "match.h" |
| 56 | #include "groupaccess.h" |
| 57 | #include "log.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 58 | #include "buffer.h" |
Damien Miller | 7acefbb | 2014-07-18 14:11:24 +1000 | [diff] [blame] | 59 | #include "misc.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 60 | #include "servconf.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 61 | #include "key.h" |
| 62 | #include "hostfile.h" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 63 | #include "auth.h" |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 64 | #include "auth-options.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 65 | #include "canohost.h" |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 66 | #include "uidswap.h" |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 67 | #include "packet.h" |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 68 | #include "loginrec.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 69 | #ifdef GSSAPI |
| 70 | #include "ssh-gss.h" |
| 71 | #endif |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 72 | #include "authfile.h" |
Darren Tucker | 269a1ea | 2005-02-03 00:20:53 +1100 | [diff] [blame] | 73 | #include "monitor_wrap.h" |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 74 | #include "authfile.h" |
| 75 | #include "ssherr.h" |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 76 | #include "compat.h" |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 77 | #include "channels.h" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 78 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 79 | /* import */ |
| 80 | extern ServerOptions options; |
Damien Miller | 7a8f5b3 | 2006-03-31 23:14:23 +1100 | [diff] [blame] | 81 | extern int use_privsep; |
Darren Tucker | b9aa0a0 | 2003-07-08 22:59:59 +1000 | [diff] [blame] | 82 | extern Buffer loginmsg; |
Damien Miller | 6433df0 | 2006-09-07 10:36:43 +1000 | [diff] [blame] | 83 | extern struct passwd *privsep_pw; |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 84 | extern struct sshauthopt *auth_opts; |
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; |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 106 | int r; |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 107 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 108 | struct spwd *spw = NULL; |
Tim Rice | 458c6bf | 2003-01-08 20:04:27 -0800 | [diff] [blame] | 109 | #endif |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 110 | |
| 111 | /* 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] | 112 | if (!pw || !pw->pw_name) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 113 | return 0; |
| 114 | |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 115 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 116 | if (!options.use_pam) |
| 117 | spw = getspnam(pw->pw_name); |
| 118 | #ifdef HAS_SHADOW_EXPIRE |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 119 | if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw)) |
| 120 | return 0; |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 121 | #endif /* HAS_SHADOW_EXPIRE */ |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 122 | #endif /* USE_SHADOW */ |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 123 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 124 | /* grab passwd field for locked account check */ |
Damien Miller | 22989f1 | 2008-07-05 08:59:43 +1000 | [diff] [blame] | 125 | passwd = pw->pw_passwd; |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 126 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 127 | if (spw != NULL) |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 128 | #ifdef USE_LIBIAF |
Tim Rice | 2291c00 | 2005-08-26 13:15:19 -0700 | [diff] [blame] | 129 | passwd = get_iaf_password(pw); |
| 130 | #else |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 131 | passwd = spw->sp_pwdp; |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 132 | #endif /* USE_LIBIAF */ |
Damien Miller | 06817f9 | 2003-01-07 23:55:59 +1100 | [diff] [blame] | 133 | #endif |
| 134 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 135 | /* check for locked account */ |
Darren Tucker | 43a0dc6 | 2003-08-26 14:22:12 +1000 | [diff] [blame] | 136 | if (!options.use_pam && passwd && *passwd) { |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 137 | int locked = 0; |
| 138 | |
| 139 | #ifdef LOCKED_PASSWD_STRING |
| 140 | if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0) |
| 141 | locked = 1; |
| 142 | #endif |
| 143 | #ifdef LOCKED_PASSWD_PREFIX |
| 144 | if (strncmp(passwd, LOCKED_PASSWD_PREFIX, |
| 145 | strlen(LOCKED_PASSWD_PREFIX)) == 0) |
| 146 | locked = 1; |
| 147 | #endif |
| 148 | #ifdef LOCKED_PASSWD_SUBSTR |
| 149 | if (strstr(passwd, LOCKED_PASSWD_SUBSTR)) |
| 150 | locked = 1; |
| 151 | #endif |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 152 | #ifdef USE_LIBIAF |
Tim Rice | ad7d547 | 2010-08-12 10:33:01 -0700 | [diff] [blame] | 153 | free((void *) passwd); |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 154 | #endif /* USE_LIBIAF */ |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 155 | if (locked) { |
| 156 | logit("User %.100s not allowed because account is locked", |
| 157 | pw->pw_name); |
| 158 | return 0; |
| 159 | } |
| 160 | } |
| 161 | |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 162 | /* |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 163 | * Deny if shell does not exist or is not executable unless we |
| 164 | * are chrooting. |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 165 | */ |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 166 | if (options.chroot_directory == NULL || |
| 167 | strcasecmp(options.chroot_directory, "none") == 0) { |
| 168 | char *shell = xstrdup((pw->pw_shell[0] == '\0') ? |
| 169 | _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ |
Darren Tucker | 94881d8 | 2010-01-15 11:44:46 +1100 | [diff] [blame] | 170 | |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 171 | if (stat(shell, &st) != 0) { |
| 172 | logit("User %.100s not allowed because shell %.100s " |
| 173 | "does not exist", pw->pw_name, shell); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 174 | free(shell); |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 175 | return 0; |
| 176 | } |
| 177 | if (S_ISREG(st.st_mode) == 0 || |
| 178 | (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { |
| 179 | logit("User %.100s not allowed because shell %.100s " |
| 180 | "is not executable", pw->pw_name, shell); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 181 | free(shell); |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 182 | return 0; |
| 183 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 184 | free(shell); |
Darren Tucker | 94881d8 | 2010-01-15 11:44:46 +1100 | [diff] [blame] | 185 | } |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 186 | |
Darren Tucker | a8f553d | 2005-03-14 23:17:27 +1100 | [diff] [blame] | 187 | if (options.num_deny_users > 0 || options.num_allow_users > 0 || |
| 188 | options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 189 | hostname = auth_get_canonical_hostname(ssh, options.use_dns); |
| 190 | ipaddr = ssh_remote_ipaddr(ssh); |
Ben Lindstrom | 3fb5d00 | 2002-03-05 01:42:42 +0000 | [diff] [blame] | 191 | } |
| 192 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 193 | /* Return false if user is listed in DenyUsers */ |
| 194 | if (options.num_deny_users > 0) { |
dtucker@openbsd.org | fe06b68 | 2016-12-15 21:29:05 +0000 | [diff] [blame] | 195 | for (i = 0; i < options.num_deny_users; i++) { |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 196 | r = match_user(pw->pw_name, hostname, ipaddr, |
| 197 | options.deny_users[i]); |
| 198 | if (r < 0) { |
| 199 | fatal("Invalid DenyUsers pattern \"%.100s\"", |
| 200 | options.deny_users[i]); |
djm@openbsd.org | 1a6f9d2 | 2016-11-08 22:04:34 +0000 | [diff] [blame] | 201 | } else if (r != 0) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 202 | logit("User %.100s from %.100s not allowed " |
| 203 | "because listed in DenyUsers", |
| 204 | pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 205 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 206 | } |
dtucker@openbsd.org | fe06b68 | 2016-12-15 21:29:05 +0000 | [diff] [blame] | 207 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 208 | } |
| 209 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
| 210 | if (options.num_allow_users > 0) { |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 211 | for (i = 0; i < options.num_allow_users; i++) { |
| 212 | r = match_user(pw->pw_name, hostname, ipaddr, |
| 213 | options.allow_users[i]); |
| 214 | if (r < 0) { |
| 215 | fatal("Invalid AllowUsers pattern \"%.100s\"", |
| 216 | options.allow_users[i]); |
| 217 | } else if (r == 1) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 218 | break; |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 219 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 220 | /* i < options.num_allow_users iff we break for loop */ |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 221 | if (i >= options.num_allow_users) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 222 | logit("User %.100s from %.100s not allowed because " |
| 223 | "not listed in AllowUsers", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 224 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 225 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 226 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 227 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 228 | /* Get the user's group access list (primary and supplementary) */ |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 229 | if (ga_init(pw->pw_name, pw->pw_gid) == 0) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 230 | logit("User %.100s from %.100s not allowed because " |
| 231 | "not in any group", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 232 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +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 one of user's groups is listed in DenyGroups */ |
| 236 | if (options.num_deny_groups > 0) |
| 237 | if (ga_match(options.deny_groups, |
| 238 | options.num_deny_groups)) { |
| 239 | ga_free(); |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 240 | logit("User %.100s from %.100s not allowed " |
| 241 | "because a group is listed in DenyGroups", |
| 242 | pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 243 | return 0; |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 244 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 245 | /* |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 246 | * 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] | 247 | * isn't listed there |
| 248 | */ |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 249 | if (options.num_allow_groups > 0) |
| 250 | if (!ga_match(options.allow_groups, |
| 251 | options.num_allow_groups)) { |
| 252 | ga_free(); |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 253 | logit("User %.100s from %.100s not allowed " |
| 254 | "because none of user's groups are listed " |
| 255 | "in AllowGroups", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 256 | return 0; |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 257 | } |
| 258 | ga_free(); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 259 | } |
| 260 | |
Darren Tucker | 0a9d43d | 2004-06-23 13:45:24 +1000 | [diff] [blame] | 261 | #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER |
Darren Tucker | 691d523 | 2005-02-15 21:45:57 +1100 | [diff] [blame] | 262 | if (!sys_auth_allowed_user(pw, &loginmsg)) |
Darren Tucker | 0a9d43d | 2004-06-23 13:45:24 +1000 | [diff] [blame] | 263 | return 0; |
| 264 | #endif |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 265 | |
| 266 | /* We found no reason not to let this user try to log on... */ |
| 267 | return 1; |
| 268 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 269 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 270 | /* |
| 271 | * Formats any key left in authctxt->auth_method_key for inclusion in |
| 272 | * auth_log()'s message. Also includes authxtct->auth_method_info if present. |
| 273 | */ |
| 274 | static char * |
| 275 | format_method_key(Authctxt *authctxt) |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 276 | { |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 277 | const struct sshkey *key = authctxt->auth_method_key; |
| 278 | const char *methinfo = authctxt->auth_method_info; |
| 279 | char *fp, *ret = NULL; |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 280 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 281 | if (key == NULL) |
| 282 | return NULL; |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 283 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 284 | if (key_is_cert(key)) { |
| 285 | fp = sshkey_fingerprint(key->cert->signature_key, |
| 286 | options.fingerprint_hash, SSH_FP_DEFAULT); |
| 287 | xasprintf(&ret, "%s ID %s (serial %llu) CA %s %s%s%s", |
| 288 | sshkey_type(key), key->cert->key_id, |
| 289 | (unsigned long long)key->cert->serial, |
| 290 | sshkey_type(key->cert->signature_key), |
| 291 | fp == NULL ? "(null)" : fp, |
| 292 | methinfo == NULL ? "" : ", ", |
| 293 | methinfo == NULL ? "" : methinfo); |
| 294 | free(fp); |
| 295 | } else { |
| 296 | fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| 297 | SSH_FP_DEFAULT); |
| 298 | xasprintf(&ret, "%s %s%s%s", sshkey_type(key), |
| 299 | fp == NULL ? "(null)" : fp, |
| 300 | methinfo == NULL ? "" : ", ", |
| 301 | methinfo == NULL ? "" : methinfo); |
| 302 | free(fp); |
| 303 | } |
| 304 | return ret; |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 305 | } |
| 306 | |
| 307 | void |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 308 | auth_log(Authctxt *authctxt, int authenticated, int partial, |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 309 | const char *method, const char *submethod) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 310 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 311 | struct ssh *ssh = active_state; /* XXX */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 312 | void (*authlog) (const char *fmt,...) = verbose; |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 313 | const char *authmsg; |
| 314 | char *extra = NULL; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 315 | |
Damien Miller | 7a8f5b3 | 2006-03-31 23:14:23 +1100 | [diff] [blame] | 316 | if (use_privsep && !mm_is_monitor() && !authctxt->postponed) |
| 317 | return; |
| 318 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 319 | /* Raise logging level */ |
| 320 | if (authenticated == 1 || |
| 321 | !authctxt->valid || |
Darren Tucker | 89413db | 2004-05-24 10:36:23 +1000 | [diff] [blame] | 322 | authctxt->failures >= options.max_authtries / 2 || |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 323 | strcmp(method, "password") == 0) |
Damien Miller | 2a3f20e | 2003-04-09 21:12:00 +1000 | [diff] [blame] | 324 | authlog = logit; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 325 | |
| 326 | if (authctxt->postponed) |
| 327 | authmsg = "Postponed"; |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 328 | else if (partial) |
| 329 | authmsg = "Partial"; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 330 | else |
| 331 | authmsg = authenticated ? "Accepted" : "Failed"; |
| 332 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 333 | if ((extra = format_method_key(authctxt)) == NULL) { |
| 334 | if (authctxt->auth_method_info != NULL) |
| 335 | extra = xstrdup(authctxt->auth_method_info); |
| 336 | } |
| 337 | |
markus@openbsd.org | 6cb6dcf | 2016-08-13 17:47:40 +0000 | [diff] [blame] | 338 | authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s", |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 339 | authmsg, |
| 340 | method, |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 341 | submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 342 | authctxt->valid ? "" : "invalid user ", |
Damien Miller | f655207 | 2001-11-12 11:06:06 +1100 | [diff] [blame] | 343 | authctxt->user, |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 344 | ssh_remote_ipaddr(ssh), |
| 345 | ssh_remote_port(ssh), |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 346 | extra != NULL ? ": " : "", |
| 347 | extra != NULL ? extra : ""); |
| 348 | |
| 349 | free(extra); |
Ben Lindstrom | e06eb68 | 2002-07-04 00:27:21 +0000 | [diff] [blame] | 350 | |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 351 | #ifdef CUSTOM_FAILED_LOGIN |
Darren Tucker | 2fba993 | 2005-02-02 23:30:24 +1100 | [diff] [blame] | 352 | if (authenticated == 0 && !authctxt->postponed && |
| 353 | (strcmp(method, "password") == 0 || |
Darren Tucker | 40d9a63 | 2005-02-04 15:19:44 +1100 | [diff] [blame] | 354 | strncmp(method, "keyboard-interactive", 20) == 0 || |
| 355 | strcmp(method, "challenge-response") == 0)) |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 356 | record_failed_login(authctxt->user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 357 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); |
Darren Tucker | 26d4e19 | 2006-08-30 22:33:09 +1000 | [diff] [blame] | 358 | # ifdef WITH_AIXAUTHENTICATE |
| 359 | if (authenticated) |
| 360 | sys_auth_record_login(authctxt->user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 361 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh", |
| 362 | &loginmsg); |
Darren Tucker | 26d4e19 | 2006-08-30 22:33:09 +1000 | [diff] [blame] | 363 | # endif |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 364 | #endif |
Darren Tucker | 2e0cf0d | 2005-02-08 21:52:47 +1100 | [diff] [blame] | 365 | #ifdef SSH_AUDIT_EVENTS |
Darren Tucker | f14b2aa | 2006-05-21 18:26:40 +1000 | [diff] [blame] | 366 | if (authenticated == 0 && !authctxt->postponed) |
| 367 | audit_event(audit_classify_auth(method)); |
Darren Tucker | 269a1ea | 2005-02-03 00:20:53 +1100 | [diff] [blame] | 368 | #endif |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 369 | } |
| 370 | |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 371 | |
| 372 | void |
| 373 | auth_maxtries_exceeded(Authctxt *authctxt) |
| 374 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 375 | struct ssh *ssh = active_state; /* XXX */ |
| 376 | |
djm@openbsd.org | 6f62160 | 2015-02-25 17:29:38 +0000 | [diff] [blame] | 377 | error("maximum authentication attempts exceeded for " |
markus@openbsd.org | 6cb6dcf | 2016-08-13 17:47:40 +0000 | [diff] [blame] | 378 | "%s%.100s from %.200s port %d ssh2", |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 379 | authctxt->valid ? "" : "invalid user ", |
| 380 | authctxt->user, |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 381 | ssh_remote_ipaddr(ssh), |
markus@openbsd.org | 6cb6dcf | 2016-08-13 17:47:40 +0000 | [diff] [blame] | 382 | ssh_remote_port(ssh)); |
djm@openbsd.org | 6f62160 | 2015-02-25 17:29:38 +0000 | [diff] [blame] | 383 | packet_disconnect("Too many authentication failures"); |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 384 | /* NOTREACHED */ |
| 385 | } |
| 386 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 387 | /* |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 388 | * Check whether root logins are disallowed. |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 389 | */ |
| 390 | int |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 391 | auth_root_allowed(struct ssh *ssh, const char *method) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 392 | { |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 393 | switch (options.permit_root_login) { |
| 394 | case PERMIT_YES: |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 395 | return 1; |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 396 | case PERMIT_NO_PASSWD: |
deraadt@openbsd.org | 1dc8d93 | 2015-08-06 14:53:21 +0000 | [diff] [blame] | 397 | if (strcmp(method, "publickey") == 0 || |
| 398 | strcmp(method, "hostbased") == 0 || |
djm@openbsd.org | 32a1819 | 2015-08-21 03:42:19 +0000 | [diff] [blame] | 399 | strcmp(method, "gssapi-with-mic") == 0) |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 400 | return 1; |
| 401 | break; |
| 402 | case PERMIT_FORCED_ONLY: |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 403 | if (auth_opts->force_command != NULL) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 404 | logit("Root login accepted for forced command."); |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 405 | return 1; |
| 406 | } |
| 407 | break; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 408 | } |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 409 | logit("ROOT LOGIN REFUSED FROM %.200s port %d", |
| 410 | ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 411 | return 0; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 412 | } |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 413 | |
| 414 | |
| 415 | /* |
| 416 | * Given a template and a passwd structure, build a filename |
| 417 | * by substituting % tokenised options. Currently, %% becomes '%', |
| 418 | * %h becomes the home directory and %u the username. |
| 419 | * |
| 420 | * This returns a buffer allocated by xmalloc. |
| 421 | */ |
Damien Miller | d8478b6 | 2011-05-29 21:39:36 +1000 | [diff] [blame] | 422 | char * |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 423 | expand_authorized_keys(const char *filename, struct passwd *pw) |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 424 | { |
djm@openbsd.org | 9c935dd | 2018-06-01 03:33:53 +0000 | [diff] [blame] | 425 | char *file, uidstr[32], ret[PATH_MAX]; |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 426 | int i; |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 427 | |
djm@openbsd.org | 9c935dd | 2018-06-01 03:33:53 +0000 | [diff] [blame] | 428 | snprintf(uidstr, sizeof(uidstr), "%llu", |
| 429 | (unsigned long long)pw->pw_uid); |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 430 | file = percent_expand(filename, "h", pw->pw_dir, |
djm@openbsd.org | 9c935dd | 2018-06-01 03:33:53 +0000 | [diff] [blame] | 431 | "u", pw->pw_name, "U", uidstr, (char *)NULL); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 432 | |
| 433 | /* |
| 434 | * Ensure that filename starts anchored. If not, be backward |
| 435 | * compatible and prepend the '%h/' |
| 436 | */ |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 437 | if (*file == '/') |
| 438 | return (file); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 439 | |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 440 | i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); |
| 441 | if (i < 0 || (size_t)i >= sizeof(ret)) |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 442 | fatal("expand_authorized_keys: path too long"); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 443 | free(file); |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 444 | return (xstrdup(ret)); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 445 | } |
| 446 | |
| 447 | char * |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 448 | authorized_principals_file(struct passwd *pw) |
| 449 | { |
djm@openbsd.org | 7e8528c | 2015-05-01 04:17:51 +0000 | [diff] [blame] | 450 | if (options.authorized_principals_file == NULL) |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 451 | return NULL; |
| 452 | return expand_authorized_keys(options.authorized_principals_file, pw); |
| 453 | } |
| 454 | |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 455 | /* return ok if key exists in sysfile or userfile */ |
| 456 | HostStatus |
markus@openbsd.org | 54d90ac | 2017-05-30 08:52:19 +0000 | [diff] [blame] | 457 | check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host, |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 458 | const char *sysfile, const char *userfile) |
| 459 | { |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 460 | char *user_hostfile; |
| 461 | struct stat st; |
Ben Lindstrom | 65366a8 | 2001-12-06 16:32:47 +0000 | [diff] [blame] | 462 | HostStatus host_status; |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 463 | struct hostkeys *hostkeys; |
| 464 | const struct hostkey_entry *found; |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 465 | |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 466 | hostkeys = init_hostkeys(); |
| 467 | load_hostkeys(hostkeys, host, sysfile); |
| 468 | if (userfile != NULL) { |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 469 | user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); |
| 470 | if (options.strict_modes && |
| 471 | (stat(user_hostfile, &st) == 0) && |
| 472 | ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 473 | (st.st_mode & 022) != 0)) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 474 | logit("Authentication refused for %.100s: " |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 475 | "bad owner or modes for %.200s", |
| 476 | pw->pw_name, user_hostfile); |
Damien Miller | 48147d6 | 2010-06-26 09:39:25 +1000 | [diff] [blame] | 477 | auth_debug_add("Ignored %.200s: bad ownership or modes", |
| 478 | user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 479 | } else { |
| 480 | temporarily_use_uid(pw); |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 481 | load_hostkeys(hostkeys, host, user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 482 | restore_uid(); |
| 483 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 484 | free(user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 485 | } |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 486 | host_status = check_key_in_hostkeys(hostkeys, key, &found); |
| 487 | if (host_status == HOST_REVOKED) |
| 488 | error("WARNING: revoked key for %s attempted authentication", |
| 489 | found->host); |
| 490 | else if (host_status == HOST_OK) |
| 491 | debug("%s: key for %s found at %s:%ld", __func__, |
| 492 | found->host, found->file, found->line); |
| 493 | else |
| 494 | debug("%s: key for host %s not found", __func__, host); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 495 | |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 496 | free_hostkeys(hostkeys); |
| 497 | |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 498 | return host_status; |
| 499 | } |
| 500 | |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 501 | static FILE * |
| 502 | auth_openfile(const char *file, struct passwd *pw, int strict_modes, |
| 503 | int log_missing, char *file_type) |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 504 | { |
| 505 | char line[1024]; |
| 506 | struct stat st; |
| 507 | int fd; |
| 508 | FILE *f; |
| 509 | |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 510 | if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) { |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 511 | if (log_missing || errno != ENOENT) |
| 512 | debug("Could not open %s '%s': %s", file_type, file, |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 513 | strerror(errno)); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 514 | return NULL; |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 515 | } |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 516 | |
| 517 | if (fstat(fd, &st) < 0) { |
| 518 | close(fd); |
| 519 | return NULL; |
| 520 | } |
| 521 | if (!S_ISREG(st.st_mode)) { |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 522 | logit("User %s %s %s is not a regular file", |
| 523 | pw->pw_name, file_type, file); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 524 | close(fd); |
| 525 | return NULL; |
| 526 | } |
| 527 | unset_nonblock(fd); |
| 528 | if ((f = fdopen(fd, "r")) == NULL) { |
| 529 | close(fd); |
| 530 | return NULL; |
| 531 | } |
Damien Miller | 6a740e7 | 2010-12-01 12:01:51 +1100 | [diff] [blame] | 532 | if (strict_modes && |
djm@openbsd.org | de4ae07 | 2017-08-18 05:36:45 +0000 | [diff] [blame] | 533 | safe_path_fd(fileno(f), file, pw, line, sizeof(line)) != 0) { |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 534 | fclose(f); |
| 535 | logit("Authentication refused: %s", line); |
Damien Miller | 48147d6 | 2010-06-26 09:39:25 +1000 | [diff] [blame] | 536 | auth_debug_add("Ignored %s: %s", file_type, line); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 537 | return NULL; |
| 538 | } |
| 539 | |
| 540 | return f; |
| 541 | } |
| 542 | |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 543 | |
| 544 | FILE * |
| 545 | auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes) |
| 546 | { |
| 547 | return auth_openfile(file, pw, strict_modes, 1, "authorized keys"); |
| 548 | } |
| 549 | |
| 550 | FILE * |
| 551 | auth_openprincipals(const char *file, struct passwd *pw, int strict_modes) |
| 552 | { |
| 553 | return auth_openfile(file, pw, strict_modes, 0, |
| 554 | "authorized principals"); |
| 555 | } |
| 556 | |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 557 | struct passwd * |
| 558 | getpwnamallow(const char *user) |
| 559 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 560 | struct ssh *ssh = active_state; /* XXX */ |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 561 | #ifdef HAVE_LOGIN_CAP |
| 562 | extern login_cap_t *lc; |
| 563 | #ifdef BSD_AUTH |
| 564 | auth_session_t *as; |
| 565 | #endif |
| 566 | #endif |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 567 | struct passwd *pw; |
Darren Tucker | fbcf827 | 2012-05-19 19:37:01 +1000 | [diff] [blame] | 568 | struct connection_info *ci = get_connection_info(1, options.use_dns); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 569 | |
Darren Tucker | fbcf827 | 2012-05-19 19:37:01 +1000 | [diff] [blame] | 570 | ci->user = user; |
| 571 | parse_server_match_config(&options, ci); |
djm@openbsd.org | 54cd41a | 2017-05-17 01:24:17 +0000 | [diff] [blame] | 572 | log_change_level(options.log_level); |
djm@openbsd.org | dbee411 | 2017-09-12 06:32:07 +0000 | [diff] [blame] | 573 | process_permitopen(ssh, &options); |
Darren Tucker | 4515047 | 2006-07-12 22:34:17 +1000 | [diff] [blame] | 574 | |
Darren Tucker | b3d20a3 | 2010-03-07 11:56:59 +1100 | [diff] [blame] | 575 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 576 | aix_setauthdb(user); |
| 577 | #endif |
| 578 | |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 579 | pw = getpwnam(user); |
Darren Tucker | b3d20a3 | 2010-03-07 11:56:59 +1100 | [diff] [blame] | 580 | |
| 581 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 582 | aix_restoreauthdb(); |
| 583 | #endif |
Damien Miller | acc9b29 | 2010-03-01 04:36:54 +1100 | [diff] [blame] | 584 | #ifdef HAVE_CYGWIN |
| 585 | /* |
| 586 | * Windows usernames are case-insensitive. To avoid later problems |
| 587 | * when trying to match the username, the user is only allowed to |
| 588 | * login if the username is given in the same case as stored in the |
| 589 | * user database. |
| 590 | */ |
| 591 | if (pw != NULL && strcmp(user, pw->pw_name) != 0) { |
| 592 | logit("Login name %.100s does not match stored username %.100s", |
| 593 | user, pw->pw_name); |
| 594 | pw = NULL; |
| 595 | } |
| 596 | #endif |
Damien Miller | 6f0a188 | 2002-09-22 01:26:51 +1000 | [diff] [blame] | 597 | if (pw == NULL) { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 598 | logit("Invalid user %.100s from %.100s port %d", |
| 599 | user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 600 | #ifdef CUSTOM_FAILED_LOGIN |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 601 | record_failed_login(user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 602 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); |
Ben Lindstrom | f5397c0 | 2002-11-09 16:11:10 +0000 | [diff] [blame] | 603 | #endif |
Darren Tucker | 2e0cf0d | 2005-02-08 21:52:47 +1100 | [diff] [blame] | 604 | #ifdef SSH_AUDIT_EVENTS |
| 605 | audit_event(SSH_INVALID_USER); |
| 606 | #endif /* SSH_AUDIT_EVENTS */ |
Damien Miller | 6f0a188 | 2002-09-22 01:26:51 +1000 | [diff] [blame] | 607 | return (NULL); |
| 608 | } |
| 609 | if (!allowed_user(pw)) |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 610 | return (NULL); |
| 611 | #ifdef HAVE_LOGIN_CAP |
| 612 | if ((lc = login_getclass(pw->pw_class)) == NULL) { |
| 613 | debug("unable to get login class: %s", user); |
| 614 | return (NULL); |
| 615 | } |
| 616 | #ifdef BSD_AUTH |
| 617 | if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || |
Damien Miller | 13e35a0 | 2002-05-22 14:04:11 +1000 | [diff] [blame] | 618 | auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 619 | debug("Approval failure for %s", user); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 620 | pw = NULL; |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 621 | } |
| 622 | if (as != NULL) |
| 623 | auth_close(as); |
| 624 | #endif |
| 625 | #endif |
Ben Lindstrom | f34e4eb | 2002-03-22 03:08:30 +0000 | [diff] [blame] | 626 | if (pw != NULL) |
| 627 | return (pwcopy(pw)); |
| 628 | return (NULL); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 629 | } |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 630 | |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 631 | /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ |
| 632 | int |
markus@openbsd.org | 54d90ac | 2017-05-30 08:52:19 +0000 | [diff] [blame] | 633 | auth_key_is_revoked(struct sshkey *key) |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 634 | { |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 635 | char *fp = NULL; |
| 636 | int r; |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 637 | |
| 638 | if (options.revoked_keys_file == NULL) |
| 639 | return 0; |
djm@openbsd.org | 56d1c83 | 2014-12-21 22:27:55 +0000 | [diff] [blame] | 640 | if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| 641 | SSH_FP_DEFAULT)) == NULL) { |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 642 | r = SSH_ERR_ALLOC_FAIL; |
| 643 | error("%s: fingerprint key: %s", __func__, ssh_err(r)); |
| 644 | goto out; |
| 645 | } |
| 646 | |
| 647 | r = sshkey_check_revoked(key, options.revoked_keys_file); |
| 648 | switch (r) { |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 649 | case 0: |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 650 | break; /* not revoked */ |
| 651 | case SSH_ERR_KEY_REVOKED: |
| 652 | error("Authentication key %s %s revoked by file %s", |
| 653 | sshkey_type(key), fp, options.revoked_keys_file); |
| 654 | goto out; |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 655 | default: |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 656 | error("Error checking authentication key %s %s in " |
| 657 | "revoked keys file %s: %s", sshkey_type(key), fp, |
| 658 | options.revoked_keys_file, ssh_err(r)); |
| 659 | goto out; |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 660 | } |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 661 | |
| 662 | /* Success */ |
| 663 | r = 0; |
| 664 | |
| 665 | out: |
| 666 | free(fp); |
| 667 | return r == 0 ? 0 : 1; |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 668 | } |
| 669 | |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 670 | void |
| 671 | auth_debug_add(const char *fmt,...) |
| 672 | { |
| 673 | char buf[1024]; |
| 674 | va_list args; |
| 675 | |
| 676 | if (!auth_debug_init) |
| 677 | return; |
| 678 | |
| 679 | va_start(args, fmt); |
| 680 | vsnprintf(buf, sizeof(buf), fmt, args); |
| 681 | va_end(args); |
| 682 | buffer_put_cstring(&auth_debug, buf); |
| 683 | } |
| 684 | |
| 685 | void |
| 686 | auth_debug_send(void) |
| 687 | { |
| 688 | char *msg; |
| 689 | |
| 690 | if (!auth_debug_init) |
| 691 | return; |
| 692 | while (buffer_len(&auth_debug)) { |
| 693 | msg = buffer_get_string(&auth_debug, NULL); |
| 694 | packet_send_debug("%s", msg); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 695 | free(msg); |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 696 | } |
| 697 | } |
| 698 | |
| 699 | void |
| 700 | auth_debug_reset(void) |
| 701 | { |
| 702 | if (auth_debug_init) |
| 703 | buffer_clear(&auth_debug); |
| 704 | else { |
| 705 | buffer_init(&auth_debug); |
| 706 | auth_debug_init = 1; |
| 707 | } |
| 708 | } |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 709 | |
| 710 | struct passwd * |
| 711 | fakepw(void) |
| 712 | { |
| 713 | static struct passwd fake; |
| 714 | |
| 715 | memset(&fake, 0, sizeof(fake)); |
| 716 | fake.pw_name = "NOUSER"; |
| 717 | fake.pw_passwd = |
Damien Miller | 787b2ec | 2003-11-21 23:56:47 +1100 | [diff] [blame] | 718 | "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK"; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 719 | #ifdef HAVE_STRUCT_PASSWD_PW_GECOS |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 720 | fake.pw_gecos = "NOUSER"; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 721 | #endif |
Damien Miller | 143c2ef | 2006-12-05 09:08:54 +1100 | [diff] [blame] | 722 | fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid; |
| 723 | 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] | 724 | #ifdef HAVE_STRUCT_PASSWD_PW_CLASS |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 725 | fake.pw_class = ""; |
| 726 | #endif |
| 727 | fake.pw_dir = "/nonexist"; |
| 728 | fake.pw_shell = "/nonexist"; |
| 729 | |
| 730 | return (&fake); |
| 731 | } |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 732 | |
| 733 | /* |
| 734 | * Returns the remote DNS hostname as a string. The returned string must not |
| 735 | * be freed. NB. this will usually trigger a DNS query the first time it is |
| 736 | * called. |
| 737 | * This function does additional checks on the hostname to mitigate some |
| 738 | * attacks on legacy rhosts-style authentication. |
| 739 | * XXX is RhostsRSAAuthentication vulnerable to these? |
| 740 | * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?) |
| 741 | */ |
| 742 | |
| 743 | static char * |
| 744 | remote_hostname(struct ssh *ssh) |
| 745 | { |
| 746 | struct sockaddr_storage from; |
| 747 | socklen_t fromlen; |
| 748 | struct addrinfo hints, *ai, *aitop; |
| 749 | char name[NI_MAXHOST], ntop2[NI_MAXHOST]; |
| 750 | const char *ntop = ssh_remote_ipaddr(ssh); |
| 751 | |
| 752 | /* Get IP address of client. */ |
| 753 | fromlen = sizeof(from); |
| 754 | memset(&from, 0, sizeof(from)); |
| 755 | if (getpeername(ssh_packet_get_connection_in(ssh), |
| 756 | (struct sockaddr *)&from, &fromlen) < 0) { |
| 757 | debug("getpeername failed: %.100s", strerror(errno)); |
| 758 | return strdup(ntop); |
| 759 | } |
| 760 | |
| 761 | ipv64_normalise_mapped(&from, &fromlen); |
| 762 | if (from.ss_family == AF_INET6) |
| 763 | fromlen = sizeof(struct sockaddr_in6); |
| 764 | |
| 765 | debug3("Trying to reverse map address %.100s.", ntop); |
| 766 | /* Map the IP address to a host name. */ |
| 767 | if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), |
| 768 | NULL, 0, NI_NAMEREQD) != 0) { |
| 769 | /* Host name not found. Use ip address. */ |
| 770 | return strdup(ntop); |
| 771 | } |
| 772 | |
| 773 | /* |
| 774 | * if reverse lookup result looks like a numeric hostname, |
| 775 | * someone is trying to trick us by PTR record like following: |
| 776 | * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 |
| 777 | */ |
| 778 | memset(&hints, 0, sizeof(hints)); |
| 779 | hints.ai_socktype = SOCK_DGRAM; /*dummy*/ |
| 780 | hints.ai_flags = AI_NUMERICHOST; |
| 781 | if (getaddrinfo(name, NULL, &hints, &ai) == 0) { |
| 782 | logit("Nasty PTR record \"%s\" is set up for %s, ignoring", |
| 783 | name, ntop); |
| 784 | freeaddrinfo(ai); |
| 785 | return strdup(ntop); |
| 786 | } |
| 787 | |
| 788 | /* Names are stored in lowercase. */ |
| 789 | lowercase(name); |
| 790 | |
| 791 | /* |
| 792 | * Map it back to an IP address and check that the given |
| 793 | * address actually is an address of this host. This is |
| 794 | * necessary because anyone with access to a name server can |
| 795 | * define arbitrary names for an IP address. Mapping from |
| 796 | * name to IP address can be trusted better (but can still be |
| 797 | * fooled if the intruder has access to the name server of |
| 798 | * the domain). |
| 799 | */ |
| 800 | memset(&hints, 0, sizeof(hints)); |
| 801 | hints.ai_family = from.ss_family; |
| 802 | hints.ai_socktype = SOCK_STREAM; |
| 803 | if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { |
| 804 | logit("reverse mapping checking getaddrinfo for %.700s " |
dtucker@openbsd.org | e690fe8 | 2016-06-15 00:40:40 +0000 | [diff] [blame] | 805 | "[%s] failed.", name, ntop); |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 806 | return strdup(ntop); |
| 807 | } |
| 808 | /* Look for the address from the list of addresses. */ |
| 809 | for (ai = aitop; ai; ai = ai->ai_next) { |
| 810 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, |
| 811 | sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && |
| 812 | (strcmp(ntop, ntop2) == 0)) |
| 813 | break; |
| 814 | } |
| 815 | freeaddrinfo(aitop); |
| 816 | /* If we reached the end of the list, the address was not there. */ |
| 817 | if (ai == NULL) { |
| 818 | /* Address not found for the host name. */ |
| 819 | logit("Address %.100s maps to %.600s, but this does not " |
dtucker@openbsd.org | e690fe8 | 2016-06-15 00:40:40 +0000 | [diff] [blame] | 820 | "map back to the address.", ntop, name); |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 821 | return strdup(ntop); |
| 822 | } |
| 823 | return strdup(name); |
| 824 | } |
| 825 | |
| 826 | /* |
| 827 | * Return the canonical name of the host in the other side of the current |
| 828 | * connection. The host name is cached, so it is efficient to call this |
| 829 | * several times. |
| 830 | */ |
| 831 | |
| 832 | const char * |
| 833 | auth_get_canonical_hostname(struct ssh *ssh, int use_dns) |
| 834 | { |
| 835 | static char *dnsname; |
| 836 | |
| 837 | if (!use_dns) |
| 838 | return ssh_remote_ipaddr(ssh); |
| 839 | else if (dnsname != NULL) |
| 840 | return dnsname; |
| 841 | else { |
| 842 | dnsname = remote_hostname(ssh); |
| 843 | return dnsname; |
| 844 | } |
| 845 | } |
markus@openbsd.org | 25cf910 | 2018-01-08 15:21:49 +0000 | [diff] [blame] | 846 | |
| 847 | /* |
| 848 | * Runs command in a subprocess wuth a minimal environment. |
| 849 | * Returns pid on success, 0 on failure. |
| 850 | * The child stdout and stderr maybe captured, left attached or sent to |
| 851 | * /dev/null depending on the contents of flags. |
| 852 | * "tag" is prepended to log messages. |
| 853 | * NB. "command" is only used for logging; the actual command executed is |
| 854 | * av[0]. |
| 855 | */ |
| 856 | pid_t |
| 857 | subprocess(const char *tag, struct passwd *pw, const char *command, |
| 858 | int ac, char **av, FILE **child, u_int flags) |
| 859 | { |
| 860 | FILE *f = NULL; |
| 861 | struct stat st; |
| 862 | int fd, devnull, p[2], i; |
| 863 | pid_t pid; |
| 864 | char *cp, errmsg[512]; |
| 865 | u_int envsize; |
| 866 | char **child_env; |
| 867 | |
| 868 | if (child != NULL) |
| 869 | *child = NULL; |
| 870 | |
| 871 | debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__, |
| 872 | tag, command, pw->pw_name, flags); |
| 873 | |
| 874 | /* Check consistency */ |
| 875 | if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && |
| 876 | (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) { |
| 877 | error("%s: inconsistent flags", __func__); |
| 878 | return 0; |
| 879 | } |
| 880 | if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) { |
| 881 | error("%s: inconsistent flags/output", __func__); |
| 882 | return 0; |
| 883 | } |
| 884 | |
| 885 | /* |
| 886 | * If executing an explicit binary, then verify the it exists |
| 887 | * and appears safe-ish to execute |
| 888 | */ |
| 889 | if (*av[0] != '/') { |
| 890 | error("%s path is not absolute", tag); |
| 891 | return 0; |
| 892 | } |
| 893 | temporarily_use_uid(pw); |
| 894 | if (stat(av[0], &st) < 0) { |
| 895 | error("Could not stat %s \"%s\": %s", tag, |
| 896 | av[0], strerror(errno)); |
| 897 | restore_uid(); |
| 898 | return 0; |
| 899 | } |
| 900 | if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) { |
| 901 | error("Unsafe %s \"%s\": %s", tag, av[0], errmsg); |
| 902 | restore_uid(); |
| 903 | return 0; |
| 904 | } |
| 905 | /* Prepare to keep the child's stdout if requested */ |
| 906 | if (pipe(p) != 0) { |
| 907 | error("%s: pipe: %s", tag, strerror(errno)); |
| 908 | restore_uid(); |
| 909 | return 0; |
| 910 | } |
| 911 | restore_uid(); |
| 912 | |
| 913 | switch ((pid = fork())) { |
| 914 | case -1: /* error */ |
| 915 | error("%s: fork: %s", tag, strerror(errno)); |
| 916 | close(p[0]); |
| 917 | close(p[1]); |
| 918 | return 0; |
| 919 | case 0: /* child */ |
| 920 | /* Prepare a minimal environment for the child. */ |
| 921 | envsize = 5; |
| 922 | child_env = xcalloc(sizeof(*child_env), envsize); |
| 923 | child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH); |
| 924 | child_set_env(&child_env, &envsize, "USER", pw->pw_name); |
| 925 | child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name); |
| 926 | child_set_env(&child_env, &envsize, "HOME", pw->pw_dir); |
| 927 | if ((cp = getenv("LANG")) != NULL) |
| 928 | child_set_env(&child_env, &envsize, "LANG", cp); |
| 929 | |
| 930 | for (i = 0; i < NSIG; i++) |
| 931 | signal(i, SIG_DFL); |
| 932 | |
| 933 | if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { |
| 934 | error("%s: open %s: %s", tag, _PATH_DEVNULL, |
| 935 | strerror(errno)); |
| 936 | _exit(1); |
| 937 | } |
| 938 | if (dup2(devnull, STDIN_FILENO) == -1) { |
| 939 | error("%s: dup2: %s", tag, strerror(errno)); |
| 940 | _exit(1); |
| 941 | } |
| 942 | |
| 943 | /* Set up stdout as requested; leave stderr in place for now. */ |
| 944 | fd = -1; |
| 945 | if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) |
| 946 | fd = p[1]; |
| 947 | else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0) |
| 948 | fd = devnull; |
| 949 | if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) { |
| 950 | error("%s: dup2: %s", tag, strerror(errno)); |
| 951 | _exit(1); |
| 952 | } |
| 953 | closefrom(STDERR_FILENO + 1); |
| 954 | |
| 955 | /* Don't use permanently_set_uid() here to avoid fatal() */ |
| 956 | if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) { |
| 957 | error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid, |
| 958 | strerror(errno)); |
| 959 | _exit(1); |
| 960 | } |
| 961 | if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) { |
| 962 | error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid, |
| 963 | strerror(errno)); |
| 964 | _exit(1); |
| 965 | } |
| 966 | /* stdin is pointed to /dev/null at this point */ |
| 967 | if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && |
| 968 | dup2(STDIN_FILENO, STDERR_FILENO) == -1) { |
| 969 | error("%s: dup2: %s", tag, strerror(errno)); |
| 970 | _exit(1); |
| 971 | } |
| 972 | |
| 973 | execve(av[0], av, child_env); |
| 974 | error("%s exec \"%s\": %s", tag, command, strerror(errno)); |
| 975 | _exit(127); |
| 976 | default: /* parent */ |
| 977 | break; |
| 978 | } |
| 979 | |
| 980 | close(p[1]); |
| 981 | if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) |
| 982 | close(p[0]); |
| 983 | else if ((f = fdopen(p[0], "r")) == NULL) { |
| 984 | error("%s: fdopen: %s", tag, strerror(errno)); |
| 985 | close(p[0]); |
| 986 | /* Don't leave zombie child */ |
| 987 | kill(pid, SIGTERM); |
| 988 | while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) |
| 989 | ; |
| 990 | return 0; |
| 991 | } |
| 992 | /* Success */ |
| 993 | debug3("%s: %s pid %ld", __func__, tag, (long)pid); |
| 994 | if (child != NULL) |
| 995 | *child = f; |
| 996 | return pid; |
| 997 | } |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 998 | |
| 999 | /* These functions link key/cert options to the auth framework */ |
| 1000 | |
| 1001 | /* Log sshauthopt options locally and (optionally) for remote transmission */ |
| 1002 | void |
| 1003 | auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote) |
| 1004 | { |
| 1005 | int do_env = options.permit_user_env && opts->nenv > 0; |
| 1006 | int do_permitopen = opts->npermitopen > 0 && |
| 1007 | (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0; |
djm@openbsd.org | 93c06ab | 2018-06-06 18:23:32 +0000 | [diff] [blame] | 1008 | int do_permitlisten = opts->npermitlisten > 0 && |
| 1009 | (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0; |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1010 | size_t i; |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1011 | char msg[1024], buf[64]; |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1012 | |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1013 | snprintf(buf, sizeof(buf), "%d", opts->force_tun_device); |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1014 | /* Try to keep this alphabetically sorted */ |
djm@openbsd.org | 93c06ab | 2018-06-06 18:23:32 +0000 | [diff] [blame] | 1015 | snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s", |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1016 | opts->permit_agent_forwarding_flag ? " agent-forwarding" : "", |
| 1017 | opts->force_command == NULL ? "" : " command", |
| 1018 | do_env ? " environment" : "", |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1019 | opts->valid_before == 0 ? "" : "expires", |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1020 | do_permitopen ? " permitopen" : "", |
djm@openbsd.org | 93c06ab | 2018-06-06 18:23:32 +0000 | [diff] [blame] | 1021 | do_permitlisten ? " permitlisten" : "", |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1022 | opts->permit_port_forwarding_flag ? " port-forwarding" : "", |
| 1023 | opts->cert_principals == NULL ? "" : " principals", |
| 1024 | opts->permit_pty_flag ? " pty" : "", |
| 1025 | opts->force_tun_device == -1 ? "" : " tun=", |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1026 | opts->force_tun_device == -1 ? "" : buf, |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1027 | opts->permit_user_rc ? " user-rc" : "", |
| 1028 | opts->permit_x11_forwarding_flag ? " x11-forwarding" : ""); |
| 1029 | |
| 1030 | debug("%s: %s", loc, msg); |
| 1031 | if (do_remote) |
| 1032 | auth_debug_add("%s: %s", loc, msg); |
| 1033 | |
| 1034 | if (options.permit_user_env) { |
| 1035 | for (i = 0; i < opts->nenv; i++) { |
| 1036 | debug("%s: environment: %s", loc, opts->env[i]); |
| 1037 | if (do_remote) { |
| 1038 | auth_debug_add("%s: environment: %s", |
| 1039 | loc, opts->env[i]); |
| 1040 | } |
| 1041 | } |
| 1042 | } |
| 1043 | |
| 1044 | /* Go into a little more details for the local logs. */ |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1045 | if (opts->valid_before != 0) { |
| 1046 | format_absolute_time(opts->valid_before, buf, sizeof(buf)); |
| 1047 | debug("%s: expires at %s", loc, buf); |
| 1048 | } |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1049 | if (opts->cert_principals != NULL) { |
| 1050 | debug("%s: authorized principals: \"%s\"", |
| 1051 | loc, opts->cert_principals); |
| 1052 | } |
| 1053 | if (opts->force_command != NULL) |
| 1054 | debug("%s: forced command: \"%s\"", loc, opts->force_command); |
djm@openbsd.org | 93c06ab | 2018-06-06 18:23:32 +0000 | [diff] [blame] | 1055 | if (do_permitopen) { |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1056 | for (i = 0; i < opts->npermitopen; i++) { |
| 1057 | debug("%s: permitted open: %s", |
| 1058 | loc, opts->permitopen[i]); |
| 1059 | } |
| 1060 | } |
djm@openbsd.org | 93c06ab | 2018-06-06 18:23:32 +0000 | [diff] [blame] | 1061 | if (do_permitlisten) { |
| 1062 | for (i = 0; i < opts->npermitlisten; i++) { |
| 1063 | debug("%s: permitted listen: %s", |
| 1064 | loc, opts->permitlisten[i]); |
| 1065 | } |
| 1066 | } |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1067 | } |
| 1068 | |
| 1069 | /* Activate a new set of key/cert options; merging with what is there. */ |
| 1070 | int |
| 1071 | auth_activate_options(struct ssh *ssh, struct sshauthopt *opts) |
| 1072 | { |
| 1073 | struct sshauthopt *old = auth_opts; |
| 1074 | const char *emsg = NULL; |
| 1075 | |
| 1076 | debug("%s: setting new authentication options", __func__); |
| 1077 | if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) { |
| 1078 | error("Inconsistent authentication options: %s", emsg); |
| 1079 | return -1; |
| 1080 | } |
| 1081 | return 0; |
| 1082 | } |
| 1083 | |
| 1084 | /* Disable forwarding, etc for the session */ |
| 1085 | void |
| 1086 | auth_restrict_session(struct ssh *ssh) |
| 1087 | { |
| 1088 | struct sshauthopt *restricted; |
| 1089 | |
| 1090 | debug("%s: restricting session", __func__); |
| 1091 | |
| 1092 | /* A blank sshauthopt defaults to permitting nothing */ |
| 1093 | restricted = sshauthopt_new(); |
djm@openbsd.org | fbb4b5f | 2018-05-25 07:11:01 +0000 | [diff] [blame] | 1094 | restricted->permit_pty_flag = 1; |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1095 | restricted->restricted = 1; |
| 1096 | |
| 1097 | if (auth_activate_options(ssh, restricted) != 0) |
| 1098 | fatal("%s: failed to restrict session", __func__); |
| 1099 | sshauthopt_free(restricted); |
| 1100 | } |
| 1101 | |
| 1102 | int |
| 1103 | auth_authorise_keyopts(struct ssh *ssh, struct passwd *pw, |
| 1104 | struct sshauthopt *opts, int allow_cert_authority, const char *loc) |
| 1105 | { |
| 1106 | const char *remote_ip = ssh_remote_ipaddr(ssh); |
| 1107 | const char *remote_host = auth_get_canonical_hostname(ssh, |
| 1108 | options.use_dns); |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1109 | time_t now = time(NULL); |
| 1110 | char buf[64]; |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1111 | |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 1112 | /* |
| 1113 | * Check keys/principals file expiry time. |
| 1114 | * NB. validity interval in certificate is handled elsewhere. |
| 1115 | */ |
| 1116 | if (opts->valid_before && now > 0 && |
| 1117 | opts->valid_before < (uint64_t)now) { |
| 1118 | format_absolute_time(opts->valid_before, buf, sizeof(buf)); |
| 1119 | debug("%s: entry expired at %s", loc, buf); |
| 1120 | auth_debug_add("%s: entry expired at %s", loc, buf); |
| 1121 | return -1; |
| 1122 | } |
djm@openbsd.org | 7c85685 | 2018-03-03 03:15:51 +0000 | [diff] [blame] | 1123 | /* Consistency checks */ |
| 1124 | if (opts->cert_principals != NULL && !opts->cert_authority) { |
| 1125 | debug("%s: principals on non-CA key", loc); |
| 1126 | auth_debug_add("%s: principals on non-CA key", loc); |
| 1127 | /* deny access */ |
| 1128 | return -1; |
| 1129 | } |
| 1130 | /* cert-authority flag isn't valid in authorized_principals files */ |
| 1131 | if (!allow_cert_authority && opts->cert_authority) { |
| 1132 | debug("%s: cert-authority flag invalid here", loc); |
| 1133 | auth_debug_add("%s: cert-authority flag invalid here", loc); |
| 1134 | /* deny access */ |
| 1135 | return -1; |
| 1136 | } |
| 1137 | |
| 1138 | /* Perform from= checks */ |
| 1139 | if (opts->required_from_host_keys != NULL) { |
| 1140 | switch (match_host_and_ip(remote_host, remote_ip, |
| 1141 | opts->required_from_host_keys )) { |
| 1142 | case 1: |
| 1143 | /* Host name matches. */ |
| 1144 | break; |
| 1145 | case -1: |
| 1146 | default: |
| 1147 | debug("%s: invalid from criteria", loc); |
| 1148 | auth_debug_add("%s: invalid from criteria", loc); |
| 1149 | /* FALLTHROUGH */ |
| 1150 | case 0: |
| 1151 | logit("%s: Authentication tried for %.100s with " |
| 1152 | "correct key but not from a permitted " |
| 1153 | "host (host=%.200s, ip=%.200s, required=%.200s).", |
| 1154 | loc, pw->pw_name, remote_host, remote_ip, |
| 1155 | opts->required_from_host_keys); |
| 1156 | auth_debug_add("%s: Your host '%.200s' is not " |
| 1157 | "permitted to use this key for login.", |
| 1158 | loc, remote_host); |
| 1159 | /* deny access */ |
| 1160 | return -1; |
| 1161 | } |
| 1162 | } |
| 1163 | /* Check source-address restriction from certificate */ |
| 1164 | if (opts->required_from_host_cert != NULL) { |
| 1165 | switch (addr_match_cidr_list(remote_ip, |
| 1166 | opts->required_from_host_cert)) { |
| 1167 | case 1: |
| 1168 | /* accepted */ |
| 1169 | break; |
| 1170 | case -1: |
| 1171 | default: |
| 1172 | /* invalid */ |
| 1173 | error("%s: Certificate source-address invalid", |
| 1174 | loc); |
| 1175 | /* FALLTHROUGH */ |
| 1176 | case 0: |
| 1177 | logit("%s: Authentication tried for %.100s with valid " |
| 1178 | "certificate but not from a permitted source " |
| 1179 | "address (%.200s).", loc, pw->pw_name, remote_ip); |
| 1180 | auth_debug_add("%s: Your address '%.200s' is not " |
| 1181 | "permitted to use this certificate for login.", |
| 1182 | loc, remote_ip); |
| 1183 | return -1; |
| 1184 | } |
| 1185 | } |
| 1186 | /* |
| 1187 | * |
| 1188 | * XXX this is spammy. We should report remotely only for keys |
| 1189 | * that are successful in actual auth attempts, and not PK_OK |
| 1190 | * tests. |
| 1191 | */ |
| 1192 | auth_log_authopts(loc, opts, 1); |
| 1193 | |
| 1194 | return 0; |
| 1195 | } |