auth-passwd.c

   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  * Created: Sat Mar 18 05:11:38 1995 ylo
   6  * Password authentication.  This file contains the functions to check whether
   7  * the password is valid for the user.
   8  */
   9
  10 #include "includes.h"
  11
  12 #ifndef USE_PAM
  13
  14 RCSID("$Id$");
  15
  16 #include "packet.h"
  17 #include "ssh.h"
  18 #include "servconf.h"
  19 #include "xmalloc.h"
  20
  21 #ifdef HAVE_SHADOW_H
  22 # include <shadow.h>
  23 #endif
  24 #if defined(HAVE_CRYPT_H) && !defined(CRYPT_H_BREAKS_BUILD)
  25 # include <crypt.h>
  26 #endif /* defined(HAVE_CRYPT_H) && !defined(CRYPT_H_BREAKS_BUILD) */
  27 #if defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT)
  28 # include "md5crypt.h"
  29 #endif /* defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT) */
  30
  31 /*
  32  * Tries to authenticate the user using password.  Returns true if
  33  * authentication succeeds.
  34  */
  35 int
  36 auth_password(struct passwd * pw, const char *password)
  37 {
  38         extern ServerOptions options;
  39         char *encrypted_password;
  40         char *pw_password;
  41         char *salt;
  42 #ifdef HAVE_SHADOW_H
  43         struct spwd *spw;
  44 #endif
  45
  46         /* deny if no user. */
  47         if (pw == NULL)
  48                 return 0;
  49         if (pw->pw_uid == 0 && options.permit_root_login == 2)
  50                 return 0;
  51         if (*password == '\0' && options.permit_empty_passwd == 0)
  52                 return 0;
  53
  54 #ifdef SKEY
  55         if (options.skey_authentication == 1) {
  56                 int ret = auth_skey_password(pw, password);
  57                 if (ret == 1 || ret == 0)
  58                         return ret;
  59                 /* Fall back to ordinary passwd authentication. */
  60         }
  61 #endif
  62 #ifdef KRB4
  63         if (options.kerberos_authentication == 1) {
  64                 int ret = auth_krb4_password(pw, password);
  65                 if (ret == 1 || ret == 0)
  66                         return ret;
  67                 /* Fall back to ordinary passwd authentication. */
  68         }
  69 #endif
  70
  71         /* Check for users with no password. */
  72         if (strcmp(password, "") == 0 && strcmp(pw->pw_passwd, "") == 0)
  73                 return 1;
  74
  75         pw_password = pw->pw_passwd;
  76
  77 #if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
  78         spw = getspnam(pw->pw_name);
  79         if (spw != NULL)
  80         {
  81                 /* Check for users with no password. */
  82                 if (strcmp(password, "") == 0 && strcmp(spw->sp_pwdp, "") == 0)
  83                         return 1;
  84
  85                 pw_password = spw->sp_pwdp;
  86         }
  87 #endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
  88
  89         if (pw_password[0] != '\0')
  90                 salt = pw_password;
  91         else
  92                 salt = "xx";
  93
  94 #ifdef HAVE_MD5_PASSWORDS
  95         if (is_md5_salt(salt))
  96                 encrypted_password = md5_crypt(password, salt);
  97         else
  98                 encrypted_password = crypt(password, salt);
  99 #else /* HAVE_MD5_PASSWORDS */
 100         encrypted_password = crypt(password, salt);
 101 #endif /* HAVE_MD5_PASSWORDS */
 102
 103         /* Authentication is accepted if the encrypted passwords are identical. */
 104         return (strcmp(encrypted_password, pw_password) == 0);
 105 }
 106 #endif /* !USE_PAM */