markus@openbsd.org | 25cf910 | 2018-01-08 15:21:49 +0000 | [diff] [blame] | 1 | /* $OpenBSD: auth.c,v 1.125 2018/01/08 15:21:49 markus 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" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 77 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 78 | /* import */ |
| 79 | extern ServerOptions options; |
Damien Miller | 7a8f5b3 | 2006-03-31 23:14:23 +1100 | [diff] [blame] | 80 | extern int use_privsep; |
Darren Tucker | b9aa0a0 | 2003-07-08 22:59:59 +1000 | [diff] [blame] | 81 | extern Buffer loginmsg; |
Damien Miller | 6433df0 | 2006-09-07 10:36:43 +1000 | [diff] [blame] | 82 | extern struct passwd *privsep_pw; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 83 | |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 84 | /* Debugging messages */ |
| 85 | Buffer auth_debug; |
| 86 | int auth_debug_init; |
| 87 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 88 | /* |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 89 | * Check if the user is allowed to log in via ssh. If user is listed |
| 90 | * in DenyUsers or one of user's groups is listed in DenyGroups, false |
| 91 | * will be returned. If AllowUsers isn't empty and user isn't listed |
| 92 | * there, or if AllowGroups isn't empty and one of user's groups isn't |
| 93 | * listed there, false will be returned. |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 94 | * If the user's shell is not executable, false will be returned. |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 95 | * Otherwise true is returned. |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 96 | */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 97 | int |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 98 | allowed_user(struct passwd * pw) |
| 99 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 100 | struct ssh *ssh = active_state; /* XXX */ |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 101 | struct stat st; |
Darren Tucker | 43a0dc6 | 2003-08-26 14:22:12 +1000 | [diff] [blame] | 102 | const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL; |
Damien Miller | eccb9de | 2005-06-17 12:59:34 +1000 | [diff] [blame] | 103 | u_int i; |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 104 | int r; |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 105 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 106 | struct spwd *spw = NULL; |
Tim Rice | 458c6bf | 2003-01-08 20:04:27 -0800 | [diff] [blame] | 107 | #endif |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 108 | |
| 109 | /* 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] | 110 | if (!pw || !pw->pw_name) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 111 | return 0; |
| 112 | |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 113 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 114 | if (!options.use_pam) |
| 115 | spw = getspnam(pw->pw_name); |
| 116 | #ifdef HAS_SHADOW_EXPIRE |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 117 | if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw)) |
| 118 | return 0; |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 119 | #endif /* HAS_SHADOW_EXPIRE */ |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 120 | #endif /* USE_SHADOW */ |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 121 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 122 | /* grab passwd field for locked account check */ |
Damien Miller | 22989f1 | 2008-07-05 08:59:43 +1000 | [diff] [blame] | 123 | passwd = pw->pw_passwd; |
Darren Tucker | 15ee748 | 2004-02-22 09:43:15 +1100 | [diff] [blame] | 124 | #ifdef USE_SHADOW |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 125 | if (spw != NULL) |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 126 | #ifdef USE_LIBIAF |
Tim Rice | 2291c00 | 2005-08-26 13:15:19 -0700 | [diff] [blame] | 127 | passwd = get_iaf_password(pw); |
| 128 | #else |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 129 | passwd = spw->sp_pwdp; |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 130 | #endif /* USE_LIBIAF */ |
Damien Miller | 06817f9 | 2003-01-07 23:55:59 +1100 | [diff] [blame] | 131 | #endif |
| 132 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 133 | /* check for locked account */ |
Darren Tucker | 43a0dc6 | 2003-08-26 14:22:12 +1000 | [diff] [blame] | 134 | if (!options.use_pam && passwd && *passwd) { |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 135 | int locked = 0; |
| 136 | |
| 137 | #ifdef LOCKED_PASSWD_STRING |
| 138 | if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0) |
| 139 | locked = 1; |
| 140 | #endif |
| 141 | #ifdef LOCKED_PASSWD_PREFIX |
| 142 | if (strncmp(passwd, LOCKED_PASSWD_PREFIX, |
| 143 | strlen(LOCKED_PASSWD_PREFIX)) == 0) |
| 144 | locked = 1; |
| 145 | #endif |
| 146 | #ifdef LOCKED_PASSWD_SUBSTR |
| 147 | if (strstr(passwd, LOCKED_PASSWD_SUBSTR)) |
| 148 | locked = 1; |
| 149 | #endif |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 150 | #ifdef USE_LIBIAF |
Tim Rice | ad7d547 | 2010-08-12 10:33:01 -0700 | [diff] [blame] | 151 | free((void *) passwd); |
Tim Rice | 99203ec | 2007-03-26 09:35:28 -0700 | [diff] [blame] | 152 | #endif /* USE_LIBIAF */ |
Darren Tucker | e41bba5 | 2003-08-25 11:51:19 +1000 | [diff] [blame] | 153 | if (locked) { |
| 154 | logit("User %.100s not allowed because account is locked", |
| 155 | pw->pw_name); |
| 156 | return 0; |
| 157 | } |
| 158 | } |
| 159 | |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 160 | /* |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 161 | * Deny if shell does not exist or is not executable unless we |
| 162 | * are chrooting. |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 163 | */ |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 164 | if (options.chroot_directory == NULL || |
| 165 | strcasecmp(options.chroot_directory, "none") == 0) { |
| 166 | char *shell = xstrdup((pw->pw_shell[0] == '\0') ? |
| 167 | _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ |
Darren Tucker | 94881d8 | 2010-01-15 11:44:46 +1100 | [diff] [blame] | 168 | |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 169 | if (stat(shell, &st) != 0) { |
| 170 | logit("User %.100s not allowed because shell %.100s " |
| 171 | "does not exist", pw->pw_name, shell); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 172 | free(shell); |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 173 | return 0; |
| 174 | } |
| 175 | if (S_ISREG(st.st_mode) == 0 || |
| 176 | (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { |
| 177 | logit("User %.100s not allowed because shell %.100s " |
| 178 | "is not executable", pw->pw_name, shell); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 179 | free(shell); |
Damien Miller | 47cf16b | 2010-02-12 09:25:29 +1100 | [diff] [blame] | 180 | return 0; |
| 181 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 182 | free(shell); |
Darren Tucker | 94881d8 | 2010-01-15 11:44:46 +1100 | [diff] [blame] | 183 | } |
Damien Miller | ef7df54 | 2000-05-19 00:03:23 +1000 | [diff] [blame] | 184 | |
Darren Tucker | a8f553d | 2005-03-14 23:17:27 +1100 | [diff] [blame] | 185 | if (options.num_deny_users > 0 || options.num_allow_users > 0 || |
| 186 | options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 187 | hostname = auth_get_canonical_hostname(ssh, options.use_dns); |
| 188 | ipaddr = ssh_remote_ipaddr(ssh); |
Ben Lindstrom | 3fb5d00 | 2002-03-05 01:42:42 +0000 | [diff] [blame] | 189 | } |
| 190 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 191 | /* Return false if user is listed in DenyUsers */ |
| 192 | if (options.num_deny_users > 0) { |
dtucker@openbsd.org | fe06b68 | 2016-12-15 21:29:05 +0000 | [diff] [blame] | 193 | for (i = 0; i < options.num_deny_users; i++) { |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 194 | r = match_user(pw->pw_name, hostname, ipaddr, |
| 195 | options.deny_users[i]); |
| 196 | if (r < 0) { |
| 197 | fatal("Invalid DenyUsers pattern \"%.100s\"", |
| 198 | options.deny_users[i]); |
djm@openbsd.org | 1a6f9d2 | 2016-11-08 22:04:34 +0000 | [diff] [blame] | 199 | } else if (r != 0) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 200 | logit("User %.100s from %.100s not allowed " |
| 201 | "because listed in DenyUsers", |
| 202 | pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 203 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 204 | } |
dtucker@openbsd.org | fe06b68 | 2016-12-15 21:29:05 +0000 | [diff] [blame] | 205 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 206 | } |
| 207 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
| 208 | if (options.num_allow_users > 0) { |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 209 | for (i = 0; i < options.num_allow_users; i++) { |
| 210 | r = match_user(pw->pw_name, hostname, ipaddr, |
| 211 | options.allow_users[i]); |
| 212 | if (r < 0) { |
| 213 | fatal("Invalid AllowUsers pattern \"%.100s\"", |
| 214 | options.allow_users[i]); |
| 215 | } else if (r == 1) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 216 | break; |
djm@openbsd.org | 010359b | 2016-11-06 05:46:37 +0000 | [diff] [blame] | 217 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 218 | /* i < options.num_allow_users iff we break for loop */ |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 219 | if (i >= options.num_allow_users) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 220 | logit("User %.100s from %.100s not allowed because " |
| 221 | "not listed in AllowUsers", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 222 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 223 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 224 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 225 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 226 | /* Get the user's group access list (primary and supplementary) */ |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 227 | if (ga_init(pw->pw_name, pw->pw_gid) == 0) { |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 228 | logit("User %.100s from %.100s not allowed because " |
| 229 | "not in any group", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 230 | return 0; |
Ben Lindstrom | 6ef9ec6 | 2002-03-05 01:40:37 +0000 | [diff] [blame] | 231 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 232 | |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 233 | /* Return false if one of user's groups is listed in DenyGroups */ |
| 234 | if (options.num_deny_groups > 0) |
| 235 | if (ga_match(options.deny_groups, |
| 236 | options.num_deny_groups)) { |
| 237 | ga_free(); |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 238 | logit("User %.100s from %.100s not allowed " |
| 239 | "because a group is listed in DenyGroups", |
| 240 | pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 241 | return 0; |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 242 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 243 | /* |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 244 | * 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] | 245 | * isn't listed there |
| 246 | */ |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 247 | if (options.num_allow_groups > 0) |
| 248 | if (!ga_match(options.allow_groups, |
| 249 | options.num_allow_groups)) { |
| 250 | ga_free(); |
Darren Tucker | 094cd0b | 2005-01-24 21:56:48 +1100 | [diff] [blame] | 251 | logit("User %.100s from %.100s not allowed " |
| 252 | "because none of user's groups are listed " |
| 253 | "in AllowGroups", pw->pw_name, hostname); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 254 | return 0; |
Kevin Steves | 7b61cfa | 2001-01-14 19:11:00 +0000 | [diff] [blame] | 255 | } |
| 256 | ga_free(); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 257 | } |
| 258 | |
Darren Tucker | 0a9d43d | 2004-06-23 13:45:24 +1000 | [diff] [blame] | 259 | #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER |
Darren Tucker | 691d523 | 2005-02-15 21:45:57 +1100 | [diff] [blame] | 260 | if (!sys_auth_allowed_user(pw, &loginmsg)) |
Darren Tucker | 0a9d43d | 2004-06-23 13:45:24 +1000 | [diff] [blame] | 261 | return 0; |
| 262 | #endif |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 263 | |
| 264 | /* We found no reason not to let this user try to log on... */ |
| 265 | return 1; |
| 266 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 267 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 268 | /* |
| 269 | * Formats any key left in authctxt->auth_method_key for inclusion in |
| 270 | * auth_log()'s message. Also includes authxtct->auth_method_info if present. |
| 271 | */ |
| 272 | static char * |
| 273 | format_method_key(Authctxt *authctxt) |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 274 | { |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 275 | const struct sshkey *key = authctxt->auth_method_key; |
| 276 | const char *methinfo = authctxt->auth_method_info; |
| 277 | char *fp, *ret = NULL; |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 278 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 279 | if (key == NULL) |
| 280 | return NULL; |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 281 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 282 | if (key_is_cert(key)) { |
| 283 | fp = sshkey_fingerprint(key->cert->signature_key, |
| 284 | options.fingerprint_hash, SSH_FP_DEFAULT); |
| 285 | xasprintf(&ret, "%s ID %s (serial %llu) CA %s %s%s%s", |
| 286 | sshkey_type(key), key->cert->key_id, |
| 287 | (unsigned long long)key->cert->serial, |
| 288 | sshkey_type(key->cert->signature_key), |
| 289 | fp == NULL ? "(null)" : fp, |
| 290 | methinfo == NULL ? "" : ", ", |
| 291 | methinfo == NULL ? "" : methinfo); |
| 292 | free(fp); |
| 293 | } else { |
| 294 | fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| 295 | SSH_FP_DEFAULT); |
| 296 | xasprintf(&ret, "%s %s%s%s", sshkey_type(key), |
| 297 | fp == NULL ? "(null)" : fp, |
| 298 | methinfo == NULL ? "" : ", ", |
| 299 | methinfo == NULL ? "" : methinfo); |
| 300 | free(fp); |
| 301 | } |
| 302 | return ret; |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 303 | } |
| 304 | |
| 305 | void |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 306 | auth_log(Authctxt *authctxt, int authenticated, int partial, |
Darren Tucker | 0acca37 | 2013-06-02 07:41:51 +1000 | [diff] [blame] | 307 | const char *method, const char *submethod) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 308 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 309 | struct ssh *ssh = active_state; /* XXX */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 310 | void (*authlog) (const char *fmt,...) = verbose; |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 311 | const char *authmsg; |
| 312 | char *extra = NULL; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 313 | |
Damien Miller | 7a8f5b3 | 2006-03-31 23:14:23 +1100 | [diff] [blame] | 314 | if (use_privsep && !mm_is_monitor() && !authctxt->postponed) |
| 315 | return; |
| 316 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 317 | /* Raise logging level */ |
| 318 | if (authenticated == 1 || |
| 319 | !authctxt->valid || |
Darren Tucker | 89413db | 2004-05-24 10:36:23 +1000 | [diff] [blame] | 320 | authctxt->failures >= options.max_authtries / 2 || |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 321 | strcmp(method, "password") == 0) |
Damien Miller | 2a3f20e | 2003-04-09 21:12:00 +1000 | [diff] [blame] | 322 | authlog = logit; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 323 | |
| 324 | if (authctxt->postponed) |
| 325 | authmsg = "Postponed"; |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 326 | else if (partial) |
| 327 | authmsg = "Partial"; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 328 | else |
| 329 | authmsg = authenticated ? "Accepted" : "Failed"; |
| 330 | |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 331 | if ((extra = format_method_key(authctxt)) == NULL) { |
| 332 | if (authctxt->auth_method_info != NULL) |
| 333 | extra = xstrdup(authctxt->auth_method_info); |
| 334 | } |
| 335 | |
markus@openbsd.org | 6cb6dcf | 2016-08-13 17:47:40 +0000 | [diff] [blame] | 336 | 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] | 337 | authmsg, |
| 338 | method, |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 339 | submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 340 | authctxt->valid ? "" : "invalid user ", |
Damien Miller | f655207 | 2001-11-12 11:06:06 +1100 | [diff] [blame] | 341 | authctxt->user, |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 342 | ssh_remote_ipaddr(ssh), |
| 343 | ssh_remote_port(ssh), |
djm@openbsd.org | 8f57495 | 2017-06-24 06:34:38 +0000 | [diff] [blame] | 344 | extra != NULL ? ": " : "", |
| 345 | extra != NULL ? extra : ""); |
| 346 | |
| 347 | free(extra); |
Ben Lindstrom | e06eb68 | 2002-07-04 00:27:21 +0000 | [diff] [blame] | 348 | |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 349 | #ifdef CUSTOM_FAILED_LOGIN |
Darren Tucker | 2fba993 | 2005-02-02 23:30:24 +1100 | [diff] [blame] | 350 | if (authenticated == 0 && !authctxt->postponed && |
| 351 | (strcmp(method, "password") == 0 || |
Darren Tucker | 40d9a63 | 2005-02-04 15:19:44 +1100 | [diff] [blame] | 352 | strncmp(method, "keyboard-interactive", 20) == 0 || |
| 353 | strcmp(method, "challenge-response") == 0)) |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 354 | record_failed_login(authctxt->user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 355 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); |
Darren Tucker | 26d4e19 | 2006-08-30 22:33:09 +1000 | [diff] [blame] | 356 | # ifdef WITH_AIXAUTHENTICATE |
| 357 | if (authenticated) |
| 358 | sys_auth_record_login(authctxt->user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 359 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh", |
| 360 | &loginmsg); |
Darren Tucker | 26d4e19 | 2006-08-30 22:33:09 +1000 | [diff] [blame] | 361 | # endif |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 362 | #endif |
Darren Tucker | 2e0cf0d | 2005-02-08 21:52:47 +1100 | [diff] [blame] | 363 | #ifdef SSH_AUDIT_EVENTS |
Darren Tucker | f14b2aa | 2006-05-21 18:26:40 +1000 | [diff] [blame] | 364 | if (authenticated == 0 && !authctxt->postponed) |
| 365 | audit_event(audit_classify_auth(method)); |
Darren Tucker | 269a1ea | 2005-02-03 00:20:53 +1100 | [diff] [blame] | 366 | #endif |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 367 | } |
| 368 | |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 369 | |
| 370 | void |
| 371 | auth_maxtries_exceeded(Authctxt *authctxt) |
| 372 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 373 | struct ssh *ssh = active_state; /* XXX */ |
| 374 | |
djm@openbsd.org | 6f62160 | 2015-02-25 17:29:38 +0000 | [diff] [blame] | 375 | error("maximum authentication attempts exceeded for " |
markus@openbsd.org | 6cb6dcf | 2016-08-13 17:47:40 +0000 | [diff] [blame] | 376 | "%s%.100s from %.200s port %d ssh2", |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 377 | authctxt->valid ? "" : "invalid user ", |
| 378 | authctxt->user, |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 379 | ssh_remote_ipaddr(ssh), |
markus@openbsd.org | 6cb6dcf | 2016-08-13 17:47:40 +0000 | [diff] [blame] | 380 | ssh_remote_port(ssh)); |
djm@openbsd.org | 6f62160 | 2015-02-25 17:29:38 +0000 | [diff] [blame] | 381 | packet_disconnect("Too many authentication failures"); |
Damien Miller | 686feb5 | 2014-07-03 21:29:38 +1000 | [diff] [blame] | 382 | /* NOTREACHED */ |
| 383 | } |
| 384 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 385 | /* |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 386 | * Check whether root logins are disallowed. |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 387 | */ |
| 388 | int |
Damien Miller | 15b05cf | 2012-12-03 09:53:20 +1100 | [diff] [blame] | 389 | auth_root_allowed(const char *method) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 390 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 391 | struct ssh *ssh = active_state; /* XXX */ |
| 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: |
| 403 | if (forced_command) { |
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 | { |
deraadt@openbsd.org | 087266e | 2015-01-20 23:14:00 +0000 | [diff] [blame] | 425 | char *file, 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 | |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 428 | file = percent_expand(filename, "h", pw->pw_dir, |
| 429 | "u", pw->pw_name, (char *)NULL); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 430 | |
| 431 | /* |
| 432 | * Ensure that filename starts anchored. If not, be backward |
| 433 | * compatible and prepend the '%h/' |
| 434 | */ |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 435 | if (*file == '/') |
| 436 | return (file); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 437 | |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 438 | i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); |
| 439 | if (i < 0 || (size_t)i >= sizeof(ret)) |
Damien Miller | 6476cad | 2005-06-16 13:18:34 +1000 | [diff] [blame] | 440 | fatal("expand_authorized_keys: path too long"); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 441 | free(file); |
Damien Miller | 07d86be | 2006-03-26 14:19:21 +1100 | [diff] [blame] | 442 | return (xstrdup(ret)); |
Ben Lindstrom | bfb3a0e | 2001-06-05 20:25:05 +0000 | [diff] [blame] | 443 | } |
| 444 | |
| 445 | char * |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 446 | authorized_principals_file(struct passwd *pw) |
| 447 | { |
djm@openbsd.org | 7e8528c | 2015-05-01 04:17:51 +0000 | [diff] [blame] | 448 | if (options.authorized_principals_file == NULL) |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 449 | return NULL; |
| 450 | return expand_authorized_keys(options.authorized_principals_file, pw); |
| 451 | } |
| 452 | |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 453 | /* return ok if key exists in sysfile or userfile */ |
| 454 | HostStatus |
markus@openbsd.org | 54d90ac | 2017-05-30 08:52:19 +0000 | [diff] [blame] | 455 | 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] | 456 | const char *sysfile, const char *userfile) |
| 457 | { |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 458 | char *user_hostfile; |
| 459 | struct stat st; |
Ben Lindstrom | 65366a8 | 2001-12-06 16:32:47 +0000 | [diff] [blame] | 460 | HostStatus host_status; |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 461 | struct hostkeys *hostkeys; |
| 462 | const struct hostkey_entry *found; |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 463 | |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 464 | hostkeys = init_hostkeys(); |
| 465 | load_hostkeys(hostkeys, host, sysfile); |
| 466 | if (userfile != NULL) { |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 467 | user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); |
| 468 | if (options.strict_modes && |
| 469 | (stat(user_hostfile, &st) == 0) && |
| 470 | ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 471 | (st.st_mode & 022) != 0)) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 472 | logit("Authentication refused for %.100s: " |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 473 | "bad owner or modes for %.200s", |
| 474 | pw->pw_name, user_hostfile); |
Damien Miller | 48147d6 | 2010-06-26 09:39:25 +1000 | [diff] [blame] | 475 | auth_debug_add("Ignored %.200s: bad ownership or modes", |
| 476 | user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 477 | } else { |
| 478 | temporarily_use_uid(pw); |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 479 | load_hostkeys(hostkeys, host, user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 480 | restore_uid(); |
| 481 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 482 | free(user_hostfile); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 483 | } |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 484 | host_status = check_key_in_hostkeys(hostkeys, key, &found); |
| 485 | if (host_status == HOST_REVOKED) |
| 486 | error("WARNING: revoked key for %s attempted authentication", |
| 487 | found->host); |
| 488 | else if (host_status == HOST_OK) |
| 489 | debug("%s: key for %s found at %s:%ld", __func__, |
| 490 | found->host, found->file, found->line); |
| 491 | else |
| 492 | debug("%s: key for host %s not found", __func__, host); |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 493 | |
Damien Miller | d925dcd | 2010-12-01 12:21:51 +1100 | [diff] [blame] | 494 | free_hostkeys(hostkeys); |
| 495 | |
Ben Lindstrom | 83647ce | 2001-06-25 04:30:16 +0000 | [diff] [blame] | 496 | return host_status; |
| 497 | } |
| 498 | |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 499 | static FILE * |
| 500 | auth_openfile(const char *file, struct passwd *pw, int strict_modes, |
| 501 | int log_missing, char *file_type) |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 502 | { |
| 503 | char line[1024]; |
| 504 | struct stat st; |
| 505 | int fd; |
| 506 | FILE *f; |
| 507 | |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 508 | if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) { |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 509 | if (log_missing || errno != ENOENT) |
| 510 | debug("Could not open %s '%s': %s", file_type, file, |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 511 | strerror(errno)); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 512 | return NULL; |
Darren Tucker | 4355152 | 2010-01-10 19:27:17 +1100 | [diff] [blame] | 513 | } |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 514 | |
| 515 | if (fstat(fd, &st) < 0) { |
| 516 | close(fd); |
| 517 | return NULL; |
| 518 | } |
| 519 | if (!S_ISREG(st.st_mode)) { |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 520 | logit("User %s %s %s is not a regular file", |
| 521 | pw->pw_name, file_type, file); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 522 | close(fd); |
| 523 | return NULL; |
| 524 | } |
| 525 | unset_nonblock(fd); |
| 526 | if ((f = fdopen(fd, "r")) == NULL) { |
| 527 | close(fd); |
| 528 | return NULL; |
| 529 | } |
Damien Miller | 6a740e7 | 2010-12-01 12:01:51 +1100 | [diff] [blame] | 530 | if (strict_modes && |
djm@openbsd.org | de4ae07 | 2017-08-18 05:36:45 +0000 | [diff] [blame] | 531 | safe_path_fd(fileno(f), file, pw, line, sizeof(line)) != 0) { |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 532 | fclose(f); |
| 533 | logit("Authentication refused: %s", line); |
Damien Miller | 48147d6 | 2010-06-26 09:39:25 +1000 | [diff] [blame] | 534 | auth_debug_add("Ignored %s: %s", file_type, line); |
Darren Tucker | 33c787f | 2008-07-02 22:37:30 +1000 | [diff] [blame] | 535 | return NULL; |
| 536 | } |
| 537 | |
| 538 | return f; |
| 539 | } |
| 540 | |
Damien Miller | 30da344 | 2010-05-10 11:58:03 +1000 | [diff] [blame] | 541 | |
| 542 | FILE * |
| 543 | auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes) |
| 544 | { |
| 545 | return auth_openfile(file, pw, strict_modes, 1, "authorized keys"); |
| 546 | } |
| 547 | |
| 548 | FILE * |
| 549 | auth_openprincipals(const char *file, struct passwd *pw, int strict_modes) |
| 550 | { |
| 551 | return auth_openfile(file, pw, strict_modes, 0, |
| 552 | "authorized principals"); |
| 553 | } |
| 554 | |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 555 | struct passwd * |
| 556 | getpwnamallow(const char *user) |
| 557 | { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 558 | struct ssh *ssh = active_state; /* XXX */ |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 559 | #ifdef HAVE_LOGIN_CAP |
| 560 | extern login_cap_t *lc; |
| 561 | #ifdef BSD_AUTH |
| 562 | auth_session_t *as; |
| 563 | #endif |
| 564 | #endif |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 565 | struct passwd *pw; |
Darren Tucker | fbcf827 | 2012-05-19 19:37:01 +1000 | [diff] [blame] | 566 | struct connection_info *ci = get_connection_info(1, options.use_dns); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 567 | |
Darren Tucker | fbcf827 | 2012-05-19 19:37:01 +1000 | [diff] [blame] | 568 | ci->user = user; |
| 569 | parse_server_match_config(&options, ci); |
djm@openbsd.org | 54cd41a | 2017-05-17 01:24:17 +0000 | [diff] [blame] | 570 | log_change_level(options.log_level); |
djm@openbsd.org | dbee411 | 2017-09-12 06:32:07 +0000 | [diff] [blame] | 571 | process_permitopen(ssh, &options); |
Darren Tucker | 4515047 | 2006-07-12 22:34:17 +1000 | [diff] [blame] | 572 | |
Darren Tucker | b3d20a3 | 2010-03-07 11:56:59 +1100 | [diff] [blame] | 573 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 574 | aix_setauthdb(user); |
| 575 | #endif |
| 576 | |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 577 | pw = getpwnam(user); |
Darren Tucker | b3d20a3 | 2010-03-07 11:56:59 +1100 | [diff] [blame] | 578 | |
| 579 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 580 | aix_restoreauthdb(); |
| 581 | #endif |
Damien Miller | acc9b29 | 2010-03-01 04:36:54 +1100 | [diff] [blame] | 582 | #ifdef HAVE_CYGWIN |
| 583 | /* |
| 584 | * Windows usernames are case-insensitive. To avoid later problems |
| 585 | * when trying to match the username, the user is only allowed to |
| 586 | * login if the username is given in the same case as stored in the |
| 587 | * user database. |
| 588 | */ |
| 589 | if (pw != NULL && strcmp(user, pw->pw_name) != 0) { |
| 590 | logit("Login name %.100s does not match stored username %.100s", |
| 591 | user, pw->pw_name); |
| 592 | pw = NULL; |
| 593 | } |
| 594 | #endif |
Damien Miller | 6f0a188 | 2002-09-22 01:26:51 +1000 | [diff] [blame] | 595 | if (pw == NULL) { |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 596 | logit("Invalid user %.100s from %.100s port %d", |
| 597 | user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); |
Darren Tucker | 97363a8 | 2003-05-02 23:42:25 +1000 | [diff] [blame] | 598 | #ifdef CUSTOM_FAILED_LOGIN |
Darren Tucker | 42d9dc7 | 2005-02-02 17:10:11 +1100 | [diff] [blame] | 599 | record_failed_login(user, |
Darren Tucker | 885fb2a | 2016-03-08 11:58:43 +1100 | [diff] [blame] | 600 | auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); |
Ben Lindstrom | f5397c0 | 2002-11-09 16:11:10 +0000 | [diff] [blame] | 601 | #endif |
Darren Tucker | 2e0cf0d | 2005-02-08 21:52:47 +1100 | [diff] [blame] | 602 | #ifdef SSH_AUDIT_EVENTS |
| 603 | audit_event(SSH_INVALID_USER); |
| 604 | #endif /* SSH_AUDIT_EVENTS */ |
Damien Miller | 6f0a188 | 2002-09-22 01:26:51 +1000 | [diff] [blame] | 605 | return (NULL); |
| 606 | } |
| 607 | if (!allowed_user(pw)) |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 608 | return (NULL); |
| 609 | #ifdef HAVE_LOGIN_CAP |
| 610 | if ((lc = login_getclass(pw->pw_class)) == NULL) { |
| 611 | debug("unable to get login class: %s", user); |
| 612 | return (NULL); |
| 613 | } |
| 614 | #ifdef BSD_AUTH |
| 615 | if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || |
Damien Miller | 13e35a0 | 2002-05-22 14:04:11 +1000 | [diff] [blame] | 616 | auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 617 | debug("Approval failure for %s", user); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 618 | pw = NULL; |
Ben Lindstrom | b481e13 | 2002-03-22 01:35:47 +0000 | [diff] [blame] | 619 | } |
| 620 | if (as != NULL) |
| 621 | auth_close(as); |
| 622 | #endif |
| 623 | #endif |
Ben Lindstrom | f34e4eb | 2002-03-22 03:08:30 +0000 | [diff] [blame] | 624 | if (pw != NULL) |
| 625 | return (pwcopy(pw)); |
| 626 | return (NULL); |
Ben Lindstrom | 2ae18f4 | 2002-03-22 01:24:38 +0000 | [diff] [blame] | 627 | } |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 628 | |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 629 | /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ |
| 630 | int |
markus@openbsd.org | 54d90ac | 2017-05-30 08:52:19 +0000 | [diff] [blame] | 631 | auth_key_is_revoked(struct sshkey *key) |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 632 | { |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 633 | char *fp = NULL; |
| 634 | int r; |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 635 | |
| 636 | if (options.revoked_keys_file == NULL) |
| 637 | return 0; |
djm@openbsd.org | 56d1c83 | 2014-12-21 22:27:55 +0000 | [diff] [blame] | 638 | if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| 639 | SSH_FP_DEFAULT)) == NULL) { |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 640 | r = SSH_ERR_ALLOC_FAIL; |
| 641 | error("%s: fingerprint key: %s", __func__, ssh_err(r)); |
| 642 | goto out; |
| 643 | } |
| 644 | |
| 645 | r = sshkey_check_revoked(key, options.revoked_keys_file); |
| 646 | switch (r) { |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 647 | case 0: |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 648 | break; /* not revoked */ |
| 649 | case SSH_ERR_KEY_REVOKED: |
| 650 | error("Authentication key %s %s revoked by file %s", |
| 651 | sshkey_type(key), fp, options.revoked_keys_file); |
| 652 | goto out; |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 653 | default: |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 654 | error("Error checking authentication key %s %s in " |
| 655 | "revoked keys file %s: %s", sshkey_type(key), fp, |
| 656 | options.revoked_keys_file, ssh_err(r)); |
| 657 | goto out; |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 658 | } |
djm@openbsd.org | 5e39a49 | 2014-12-04 02:24:32 +0000 | [diff] [blame] | 659 | |
| 660 | /* Success */ |
| 661 | r = 0; |
| 662 | |
| 663 | out: |
| 664 | free(fp); |
| 665 | return r == 0 ? 0 : 1; |
Damien Miller | 1aed65e | 2010-03-04 21:53:35 +1100 | [diff] [blame] | 666 | } |
| 667 | |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 668 | void |
| 669 | auth_debug_add(const char *fmt,...) |
| 670 | { |
| 671 | char buf[1024]; |
| 672 | va_list args; |
| 673 | |
| 674 | if (!auth_debug_init) |
| 675 | return; |
| 676 | |
| 677 | va_start(args, fmt); |
| 678 | vsnprintf(buf, sizeof(buf), fmt, args); |
| 679 | va_end(args); |
| 680 | buffer_put_cstring(&auth_debug, buf); |
| 681 | } |
| 682 | |
| 683 | void |
| 684 | auth_debug_send(void) |
| 685 | { |
| 686 | char *msg; |
| 687 | |
| 688 | if (!auth_debug_init) |
| 689 | return; |
| 690 | while (buffer_len(&auth_debug)) { |
| 691 | msg = buffer_get_string(&auth_debug, NULL); |
| 692 | packet_send_debug("%s", msg); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 693 | free(msg); |
Ben Lindstrom | a574cda | 2002-05-15 16:16:14 +0000 | [diff] [blame] | 694 | } |
| 695 | } |
| 696 | |
| 697 | void |
| 698 | auth_debug_reset(void) |
| 699 | { |
| 700 | if (auth_debug_init) |
| 701 | buffer_clear(&auth_debug); |
| 702 | else { |
| 703 | buffer_init(&auth_debug); |
| 704 | auth_debug_init = 1; |
| 705 | } |
| 706 | } |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 707 | |
| 708 | struct passwd * |
| 709 | fakepw(void) |
| 710 | { |
| 711 | static struct passwd fake; |
| 712 | |
| 713 | memset(&fake, 0, sizeof(fake)); |
| 714 | fake.pw_name = "NOUSER"; |
| 715 | fake.pw_passwd = |
Damien Miller | 787b2ec | 2003-11-21 23:56:47 +1100 | [diff] [blame] | 716 | "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK"; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 717 | #ifdef HAVE_STRUCT_PASSWD_PW_GECOS |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 718 | fake.pw_gecos = "NOUSER"; |
Damien Miller | 6332da2 | 2013-04-23 14:25:52 +1000 | [diff] [blame] | 719 | #endif |
Damien Miller | 143c2ef | 2006-12-05 09:08:54 +1100 | [diff] [blame] | 720 | fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid; |
| 721 | 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] | 722 | #ifdef HAVE_STRUCT_PASSWD_PW_CLASS |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 723 | fake.pw_class = ""; |
| 724 | #endif |
| 725 | fake.pw_dir = "/nonexist"; |
| 726 | fake.pw_shell = "/nonexist"; |
| 727 | |
| 728 | return (&fake); |
| 729 | } |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 730 | |
| 731 | /* |
| 732 | * Returns the remote DNS hostname as a string. The returned string must not |
| 733 | * be freed. NB. this will usually trigger a DNS query the first time it is |
| 734 | * called. |
| 735 | * This function does additional checks on the hostname to mitigate some |
| 736 | * attacks on legacy rhosts-style authentication. |
| 737 | * XXX is RhostsRSAAuthentication vulnerable to these? |
| 738 | * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?) |
| 739 | */ |
| 740 | |
| 741 | static char * |
| 742 | remote_hostname(struct ssh *ssh) |
| 743 | { |
| 744 | struct sockaddr_storage from; |
| 745 | socklen_t fromlen; |
| 746 | struct addrinfo hints, *ai, *aitop; |
| 747 | char name[NI_MAXHOST], ntop2[NI_MAXHOST]; |
| 748 | const char *ntop = ssh_remote_ipaddr(ssh); |
| 749 | |
| 750 | /* Get IP address of client. */ |
| 751 | fromlen = sizeof(from); |
| 752 | memset(&from, 0, sizeof(from)); |
| 753 | if (getpeername(ssh_packet_get_connection_in(ssh), |
| 754 | (struct sockaddr *)&from, &fromlen) < 0) { |
| 755 | debug("getpeername failed: %.100s", strerror(errno)); |
| 756 | return strdup(ntop); |
| 757 | } |
| 758 | |
| 759 | ipv64_normalise_mapped(&from, &fromlen); |
| 760 | if (from.ss_family == AF_INET6) |
| 761 | fromlen = sizeof(struct sockaddr_in6); |
| 762 | |
| 763 | debug3("Trying to reverse map address %.100s.", ntop); |
| 764 | /* Map the IP address to a host name. */ |
| 765 | if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), |
| 766 | NULL, 0, NI_NAMEREQD) != 0) { |
| 767 | /* Host name not found. Use ip address. */ |
| 768 | return strdup(ntop); |
| 769 | } |
| 770 | |
| 771 | /* |
| 772 | * if reverse lookup result looks like a numeric hostname, |
| 773 | * someone is trying to trick us by PTR record like following: |
| 774 | * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 |
| 775 | */ |
| 776 | memset(&hints, 0, sizeof(hints)); |
| 777 | hints.ai_socktype = SOCK_DGRAM; /*dummy*/ |
| 778 | hints.ai_flags = AI_NUMERICHOST; |
| 779 | if (getaddrinfo(name, NULL, &hints, &ai) == 0) { |
| 780 | logit("Nasty PTR record \"%s\" is set up for %s, ignoring", |
| 781 | name, ntop); |
| 782 | freeaddrinfo(ai); |
| 783 | return strdup(ntop); |
| 784 | } |
| 785 | |
| 786 | /* Names are stored in lowercase. */ |
| 787 | lowercase(name); |
| 788 | |
| 789 | /* |
| 790 | * Map it back to an IP address and check that the given |
| 791 | * address actually is an address of this host. This is |
| 792 | * necessary because anyone with access to a name server can |
| 793 | * define arbitrary names for an IP address. Mapping from |
| 794 | * name to IP address can be trusted better (but can still be |
| 795 | * fooled if the intruder has access to the name server of |
| 796 | * the domain). |
| 797 | */ |
| 798 | memset(&hints, 0, sizeof(hints)); |
| 799 | hints.ai_family = from.ss_family; |
| 800 | hints.ai_socktype = SOCK_STREAM; |
| 801 | if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { |
| 802 | logit("reverse mapping checking getaddrinfo for %.700s " |
dtucker@openbsd.org | e690fe8 | 2016-06-15 00:40:40 +0000 | [diff] [blame] | 803 | "[%s] failed.", name, ntop); |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 804 | return strdup(ntop); |
| 805 | } |
| 806 | /* Look for the address from the list of addresses. */ |
| 807 | for (ai = aitop; ai; ai = ai->ai_next) { |
| 808 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, |
| 809 | sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && |
| 810 | (strcmp(ntop, ntop2) == 0)) |
| 811 | break; |
| 812 | } |
| 813 | freeaddrinfo(aitop); |
| 814 | /* If we reached the end of the list, the address was not there. */ |
| 815 | if (ai == NULL) { |
| 816 | /* Address not found for the host name. */ |
| 817 | logit("Address %.100s maps to %.600s, but this does not " |
dtucker@openbsd.org | e690fe8 | 2016-06-15 00:40:40 +0000 | [diff] [blame] | 818 | "map back to the address.", ntop, name); |
djm@openbsd.org | 9576726 | 2016-03-07 19:02:43 +0000 | [diff] [blame] | 819 | return strdup(ntop); |
| 820 | } |
| 821 | return strdup(name); |
| 822 | } |
| 823 | |
| 824 | /* |
| 825 | * Return the canonical name of the host in the other side of the current |
| 826 | * connection. The host name is cached, so it is efficient to call this |
| 827 | * several times. |
| 828 | */ |
| 829 | |
| 830 | const char * |
| 831 | auth_get_canonical_hostname(struct ssh *ssh, int use_dns) |
| 832 | { |
| 833 | static char *dnsname; |
| 834 | |
| 835 | if (!use_dns) |
| 836 | return ssh_remote_ipaddr(ssh); |
| 837 | else if (dnsname != NULL) |
| 838 | return dnsname; |
| 839 | else { |
| 840 | dnsname = remote_hostname(ssh); |
| 841 | return dnsname; |
| 842 | } |
| 843 | } |
markus@openbsd.org | 25cf910 | 2018-01-08 15:21:49 +0000 | [diff] [blame] | 844 | |
| 845 | /* |
| 846 | * Runs command in a subprocess wuth a minimal environment. |
| 847 | * Returns pid on success, 0 on failure. |
| 848 | * The child stdout and stderr maybe captured, left attached or sent to |
| 849 | * /dev/null depending on the contents of flags. |
| 850 | * "tag" is prepended to log messages. |
| 851 | * NB. "command" is only used for logging; the actual command executed is |
| 852 | * av[0]. |
| 853 | */ |
| 854 | pid_t |
| 855 | subprocess(const char *tag, struct passwd *pw, const char *command, |
| 856 | int ac, char **av, FILE **child, u_int flags) |
| 857 | { |
| 858 | FILE *f = NULL; |
| 859 | struct stat st; |
| 860 | int fd, devnull, p[2], i; |
| 861 | pid_t pid; |
| 862 | char *cp, errmsg[512]; |
| 863 | u_int envsize; |
| 864 | char **child_env; |
| 865 | |
| 866 | if (child != NULL) |
| 867 | *child = NULL; |
| 868 | |
| 869 | debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__, |
| 870 | tag, command, pw->pw_name, flags); |
| 871 | |
| 872 | /* Check consistency */ |
| 873 | if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && |
| 874 | (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) { |
| 875 | error("%s: inconsistent flags", __func__); |
| 876 | return 0; |
| 877 | } |
| 878 | if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) { |
| 879 | error("%s: inconsistent flags/output", __func__); |
| 880 | return 0; |
| 881 | } |
| 882 | |
| 883 | /* |
| 884 | * If executing an explicit binary, then verify the it exists |
| 885 | * and appears safe-ish to execute |
| 886 | */ |
| 887 | if (*av[0] != '/') { |
| 888 | error("%s path is not absolute", tag); |
| 889 | return 0; |
| 890 | } |
| 891 | temporarily_use_uid(pw); |
| 892 | if (stat(av[0], &st) < 0) { |
| 893 | error("Could not stat %s \"%s\": %s", tag, |
| 894 | av[0], strerror(errno)); |
| 895 | restore_uid(); |
| 896 | return 0; |
| 897 | } |
| 898 | if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) { |
| 899 | error("Unsafe %s \"%s\": %s", tag, av[0], errmsg); |
| 900 | restore_uid(); |
| 901 | return 0; |
| 902 | } |
| 903 | /* Prepare to keep the child's stdout if requested */ |
| 904 | if (pipe(p) != 0) { |
| 905 | error("%s: pipe: %s", tag, strerror(errno)); |
| 906 | restore_uid(); |
| 907 | return 0; |
| 908 | } |
| 909 | restore_uid(); |
| 910 | |
| 911 | switch ((pid = fork())) { |
| 912 | case -1: /* error */ |
| 913 | error("%s: fork: %s", tag, strerror(errno)); |
| 914 | close(p[0]); |
| 915 | close(p[1]); |
| 916 | return 0; |
| 917 | case 0: /* child */ |
| 918 | /* Prepare a minimal environment for the child. */ |
| 919 | envsize = 5; |
| 920 | child_env = xcalloc(sizeof(*child_env), envsize); |
| 921 | child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH); |
| 922 | child_set_env(&child_env, &envsize, "USER", pw->pw_name); |
| 923 | child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name); |
| 924 | child_set_env(&child_env, &envsize, "HOME", pw->pw_dir); |
| 925 | if ((cp = getenv("LANG")) != NULL) |
| 926 | child_set_env(&child_env, &envsize, "LANG", cp); |
| 927 | |
| 928 | for (i = 0; i < NSIG; i++) |
| 929 | signal(i, SIG_DFL); |
| 930 | |
| 931 | if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { |
| 932 | error("%s: open %s: %s", tag, _PATH_DEVNULL, |
| 933 | strerror(errno)); |
| 934 | _exit(1); |
| 935 | } |
| 936 | if (dup2(devnull, STDIN_FILENO) == -1) { |
| 937 | error("%s: dup2: %s", tag, strerror(errno)); |
| 938 | _exit(1); |
| 939 | } |
| 940 | |
| 941 | /* Set up stdout as requested; leave stderr in place for now. */ |
| 942 | fd = -1; |
| 943 | if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) |
| 944 | fd = p[1]; |
| 945 | else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0) |
| 946 | fd = devnull; |
| 947 | if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) { |
| 948 | error("%s: dup2: %s", tag, strerror(errno)); |
| 949 | _exit(1); |
| 950 | } |
| 951 | closefrom(STDERR_FILENO + 1); |
| 952 | |
| 953 | /* Don't use permanently_set_uid() here to avoid fatal() */ |
| 954 | if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) { |
| 955 | error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid, |
| 956 | strerror(errno)); |
| 957 | _exit(1); |
| 958 | } |
| 959 | if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) { |
| 960 | error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid, |
| 961 | strerror(errno)); |
| 962 | _exit(1); |
| 963 | } |
| 964 | /* stdin is pointed to /dev/null at this point */ |
| 965 | if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && |
| 966 | dup2(STDIN_FILENO, STDERR_FILENO) == -1) { |
| 967 | error("%s: dup2: %s", tag, strerror(errno)); |
| 968 | _exit(1); |
| 969 | } |
| 970 | |
| 971 | execve(av[0], av, child_env); |
| 972 | error("%s exec \"%s\": %s", tag, command, strerror(errno)); |
| 973 | _exit(127); |
| 974 | default: /* parent */ |
| 975 | break; |
| 976 | } |
| 977 | |
| 978 | close(p[1]); |
| 979 | if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) |
| 980 | close(p[0]); |
| 981 | else if ((f = fdopen(p[0], "r")) == NULL) { |
| 982 | error("%s: fdopen: %s", tag, strerror(errno)); |
| 983 | close(p[0]); |
| 984 | /* Don't leave zombie child */ |
| 985 | kill(pid, SIGTERM); |
| 986 | while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) |
| 987 | ; |
| 988 | return 0; |
| 989 | } |
| 990 | /* Success */ |
| 991 | debug3("%s: %s pid %ld", __func__, tag, (long)pid); |
| 992 | if (child != NULL) |
| 993 | *child = f; |
| 994 | return pid; |
| 995 | } |