1 /*
   2  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   3  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   4  *                    All rights reserved
   5  * Password authentication.  This file contains the functions to check whether
   6  * the password is valid for the user.
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  *
  14  * Copyright (c) 1999 Dug Song.  All rights reserved.
  15  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37 
  38 #include "includes.h"
  39 RCSID("$OpenBSD: auth-passwd.c,v 1.27 2002/05/24 16:45:16 stevesk Exp $");
  40 
  41 #include "packet.h"
  42 #include "log.h"
  43 #include "servconf.h"
  44 #include "auth.h"
  45 
  46 #if !defined(USE_PAM) && !defined(HAVE_OSF_SIA)
  47 /* Don't need any of these headers for the PAM or SIA cases */
  48 # ifdef HAVE_CRYPT_H
  49 #  include <crypt.h>
  50 # endif
  51 # ifdef WITH_AIXAUTHENTICATE
  52 #  include <login.h>
  53 # endif
  54 # ifdef __hpux
  55 #  include <hpsecurity.h>
  56 #  include <prot.h>
  57 # endif
  58 # if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
  59 #  include <shadow.h>
  60 # endif
  61 # if defined(HAVE_GETPWANAM) && !defined(DISABLE_SHADOW)
  62 #  include <sys/label.h>
  63 #  include <sys/audit.h>
  64 #  include <pwdadj.h>
  65 # endif
  66 # if defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT)
  67 #  include "md5crypt.h"
  68 # endif /* defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT) */
  69 
  70 # ifdef HAVE_CYGWIN
  71 #  undef ERROR
  72 #  include <windows.h>
  73 #  include <sys/cygwin.h>
  74 #  define is_winnt       (GetVersion() < 0x80000000)
  75 # endif
  76 #endif /* !USE_PAM && !HAVE_OSF_SIA */
  77 
  78 extern ServerOptions options;
  79 #ifdef WITH_AIXAUTHENTICATE
  80 extern char *aixloginmsg;
  81 #endif
  82 
  83 /*
  84  * Tries to authenticate the user using password.  Returns true if
  85  * authentication succeeds.
  86  */
  87 int
  88 auth_password(Authctxt *authctxt, const char *password)
  89 {
  90 #if defined(USE_PAM)
  91         if (*password == '\0' && options.permit_empty_passwd == 0)
  92                 return 0;
  93         return auth_pam_password(authctxt, password);
  94 #elif defined(HAVE_OSF_SIA)
  95         if (*password == '\0' && options.permit_empty_passwd == 0)
  96                 return 0;
  97         return auth_sia_password(authctxt, password);
  98 #else
  99         struct passwd * pw = authctxt->pw;
 100         char *encrypted_password;
 101         char *pw_password;
 102         char *salt;
 103 #if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
 104         struct spwd *spw;
 105 #endif
 106 #if defined(HAVE_GETPWANAM) && !defined(DISABLE_SHADOW)
 107         struct passwd_adjunct *spw;
 108 #endif
 109 #ifdef WITH_AIXAUTHENTICATE
 110         char *authmsg;
 111         int authsuccess;
 112         int reenter = 1;
 113 #endif
 114 
 115         /* deny if no user. */
 116         if (pw == NULL)
 117                 return 0;
 118 #ifndef HAVE_CYGWIN
 119        if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
 120                 return 0;
 121 #endif
 122         if (*password == '\0' && options.permit_empty_passwd == 0)
 123                 return 0;
 124 #ifdef KRB5
 125         if (options.kerberos_authentication == 1) {
 126                 int ret = auth_krb5_password(authctxt, password);
 127                 if (ret == 1 || ret == 0)
 128                         return ret;
 129                 /* Fall back to ordinary passwd authentication. */
 130         }
 131 #endif
 132 #ifdef HAVE_CYGWIN
 133         if (is_winnt) {
 134                 HANDLE hToken = cygwin_logon_user(pw, password);
 135 
 136                 if (hToken == INVALID_HANDLE_VALUE)
 137                         return 0;
 138                 cygwin_set_impersonation_token(hToken);
 139                 return 1;
 140         }
 141 #endif
 142 #ifdef WITH_AIXAUTHENTICATE
 143         authsuccess = (authenticate(pw->pw_name,password,&reenter,&authmsg) == 0);
 144 
 145         if (authsuccess)
 146                 /* We don't have a pty yet, so just label the line as "ssh" */
 147                 if (loginsuccess(authctxt->user,
 148                         get_canonical_hostname(options.verify_reverse_mapping),
 149                         "ssh", &aixloginmsg) < 0)
 150                                 aixloginmsg = NULL;
 151 
 152         return(authsuccess);
 153 #endif
 154 #ifdef KRB4
 155         if (options.kerberos_authentication == 1) {
 156                 int ret = auth_krb4_password(authctxt, password);
 157                 if (ret == 1 || ret == 0)
 158                         return ret;
 159                 /* Fall back to ordinary passwd authentication. */
 160         }
 161 #endif
 162 #ifdef BSD_AUTH
 163         if (auth_userokay(pw->pw_name, authctxt->style, "auth-ssh",
 164             (char *)password) == 0)
 165                 return 0;
 166         else
 167                 return 1;
 168 #endif
 169         pw_password = pw->pw_passwd;
 170 
 171         /*
 172          * Various interfaces to shadow or protected password data
 173          */
 174 #if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
 175         spw = getspnam(pw->pw_name);
 176         if (spw != NULL)
 177                 pw_password = spw->sp_pwdp;
 178 #endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
 179 
 180 #if defined(HAVE_GETPWANAM) && !defined(DISABLE_SHADOW)
 181         if (issecure() && (spw = getpwanam(pw->pw_name)) != NULL)
 182                 pw_password = spw->pwa_passwd;
 183 #endif /* defined(HAVE_GETPWANAM) && !defined(DISABLE_SHADOW) */
 184 
 185         /* Check for users with no password. */
 186         if ((password[0] == '\0') && (pw_password[0] == '\0'))
 187                 return 1;
 188 
 189         if (pw_password[0] != '\0')
 190                 salt = pw_password;
 191         else
 192                 salt = "xx";
 193 
 194 #ifdef HAVE_MD5_PASSWORDS
 195         if (is_md5_salt(salt))
 196                 encrypted_password = md5_crypt(password, salt);
 197         else
 198                 encrypted_password = crypt(password, salt);
 199 #else /* HAVE_MD5_PASSWORDS */
 200         encrypted_password = crypt(password, salt);
 201 #endif /* HAVE_MD5_PASSWORDS */
 202 
 203         /* Authentication is accepted if the encrypted passwords are identical. */
 204         return (strcmp(encrypted_password, pw_password) == 0);
 205 #endif /* !USE_PAM && !HAVE_OSF_SIA */
 206 }