svr-authpasswd.c

   1 /*
   2  * Dropbear - a SSH2 server
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE. */
  24
  25 /* Validates a user password */
  26
  27 #include "includes.h"
  28 #include "session.h"
  29 #include "buffer.h"
  30 #include "dbutil.h"
  31 #include "auth.h"
  32
  33 #ifdef ENABLE_SVR_PASSWORD_AUTH
  34
  35 /* Process a password auth request, sending success or failure messages as
  36  * appropriate */
  37 void svr_auth_password() {
  38
  39 #ifdef HAVE_SHADOW_H
  40         struct spwd *spasswd = NULL;
  41 #endif
  42         char * passwdcrypt = NULL; /* the crypt from /etc/passwd or /etc/shadow */
  43         char * testcrypt = NULL; /* crypt generated from the user's password sent */
  44         unsigned char * password;
  45         unsigned int passwordlen;
  46
  47         unsigned int changepw;
  48
  49         passwdcrypt = ses.authstate.pw_passwd;
  50 #ifdef HAVE_SHADOW_H
  51         /* get the shadow password if possible */
  52         spasswd = getspnam(ses.authstate.pw_name);
  53         if (spasswd != NULL && spasswd->sp_pwdp != NULL) {
  54                 passwdcrypt = spasswd->sp_pwdp;
  55         }
  56 #endif
  57
  58 #ifdef DEBUG_HACKCRYPT
  59         /* debugging crypt for non-root testing with shadows */
  60         passwdcrypt = DEBUG_HACKCRYPT;
  61 #endif
  62
  63         /* check for empty password - need to do this again here
  64          * since the shadow password may differ to that tested
  65          * in auth.c */
  66         if (passwdcrypt[0] == '\0') {
  67                 dropbear_log(LOG_WARNING, "user '%s' has blank password, rejected",
  68                                 ses.authstate.pw_name);
  69                 send_msg_userauth_failure(0, 1);
  70                 return;
  71         }
  72
  73         /* check if client wants to change password */
  74         changepw = buf_getbool(ses.payload);
  75         if (changepw) {
  76                 /* not implemented by this server */
  77                 send_msg_userauth_failure(0, 1);
  78                 return;
  79         }
  80
  81         password = buf_getstring(ses.payload, &passwordlen);
  82
  83         /* the first bytes of passwdcrypt are the salt */
  84         testcrypt = crypt((char*)password, passwdcrypt);
  85         m_burn(password, passwordlen);
  86         m_free(password);
  87
  88         if (strcmp(testcrypt, passwdcrypt) == 0) {
  89                 /* successful authentication */
  90                 dropbear_log(LOG_NOTICE,
  91                                 "password auth succeeded for '%s' from %s",
  92                                 ses.authstate.pw_name,
  93                                 svr_ses.addrstring);
  94                 send_msg_userauth_success();
  95         } else {
  96                 dropbear_log(LOG_WARNING,
  97                                 "bad password attempt for '%s' from %s",
  98                                 ses.authstate.pw_name,
  99                                 svr_ses.addrstring);
 100                 send_msg_userauth_failure(0, 1);
 101         }
 102
 103 }
 104
 105 #endif