source/libsmb/credentials.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    code to manipulate domain credentials
   5    Copyright (C) Andrew Tridgell 1997-1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 /****************************************************************************
  25 represent a credential as a string
  26 ****************************************************************************/
  27 char *credstr(const uchar *cred)
  28 {
  29         static fstring buf;
  30         slprintf(buf, sizeof(buf) - 1, "%02X%02X%02X%02X%02X%02X%02X%02X",
  31                 cred[0], cred[1], cred[2], cred[3],
  32                 cred[4], cred[5], cred[6], cred[7]);
  33         return buf;
  34 }
  35
  36
  37 /****************************************************************************
  38   setup the session key.
  39 Input: 8 byte challenge block
  40        8 byte server challenge block
  41       16 byte md4 encrypted password
  42 Output:
  43       8 byte session key
  44 ****************************************************************************/
  45 void cred_session_key(const DOM_CHAL *clnt_chal, const DOM_CHAL *srv_chal, const uchar *pass,
  46                         uchar session_key[8])
  47 {
  48         uint32 sum[2];
  49         unsigned char sum2[8];
  50
  51         sum[0] = IVAL(clnt_chal->data, 0) + IVAL(srv_chal->data, 0);
  52         sum[1] = IVAL(clnt_chal->data, 4) + IVAL(srv_chal->data, 4);
  53
  54         SIVAL(sum2,0,sum[0]);
  55         SIVAL(sum2,4,sum[1]);
  56
  57         cred_hash1(session_key, sum2,pass);
  58
  59         /* debug output */
  60         DEBUG(4,("cred_session_key\n"));
  61
  62         DEBUG(5,("      clnt_chal: %s\n", credstr(clnt_chal->data)));
  63         DEBUG(5,("      srv_chal : %s\n", credstr(srv_chal->data)));
  64         DEBUG(5,("      clnt+srv : %s\n", credstr(sum2)));
  65         DEBUG(5,("      sess_key : %s\n", credstr(session_key)));
  66 }
  67
  68
  69 /****************************************************************************
  70 create a credential
  71
  72 Input:
  73       8 byte sesssion key
  74       8 byte stored credential
  75       4 byte timestamp
  76
  77 Output:
  78       8 byte credential
  79 ****************************************************************************/
  80 void cred_create(uchar session_key[8], DOM_CHAL *stor_cred, UTIME timestamp,
  81                  DOM_CHAL *cred)
  82 {
  83         DOM_CHAL time_cred;
  84
  85         SIVAL(time_cred.data, 0, IVAL(stor_cred->data, 0) + timestamp.time);
  86         SIVAL(time_cred.data, 4, IVAL(stor_cred->data, 4));
  87
  88         cred_hash2(cred->data, time_cred.data, session_key);
  89
  90         /* debug output*/
  91         DEBUG(4,("cred_create\n"));
  92
  93         DEBUG(5,("      sess_key : %s\n", credstr(session_key)));
  94         DEBUG(5,("      stor_cred: %s\n", credstr(stor_cred->data)));
  95         DEBUG(5,("      timestamp: %x\n"    , timestamp.time));
  96         DEBUG(5,("      timecred : %s\n", credstr(time_cred.data)));
  97         DEBUG(5,("      calc_cred: %s\n", credstr(cred->data)));
  98 }
  99
 100
 101 /****************************************************************************
 102   check a supplied credential
 103
 104 Input:
 105       8 byte received credential
 106       8 byte sesssion key
 107       8 byte stored credential
 108       4 byte timestamp
 109
 110 Output:
 111       returns 1 if computed credential matches received credential
 112       returns 0 otherwise
 113 ****************************************************************************/
 114 int cred_assert(DOM_CHAL *cred, uchar session_key[8], DOM_CHAL *stored_cred,
 115                 UTIME timestamp)
 116 {
 117         DOM_CHAL cred2;
 118
 119         cred_create(session_key, stored_cred, timestamp, &cred2);
 120
 121         /* debug output*/
 122         DEBUG(4,("cred_assert\n"));
 123
 124         DEBUG(5,("      challenge : %s\n", credstr(cred->data)));
 125         DEBUG(5,("      calculated: %s\n", credstr(cred2.data)));
 126
 127         if (memcmp(cred->data, cred2.data, 8) == 0)
 128         {
 129                 DEBUG(5, ("credentials check ok\n"));
 130                 return True;
 131         }
 132         else
 133         {
 134                 DEBUG(5, ("credentials check wrong\n"));
 135                 return False;
 136         }
 137 }
 138
 139
 140 /****************************************************************************
 141   checks credentials; generates next step in the credential chain
 142 ****************************************************************************/
 143 BOOL clnt_deal_with_creds(uchar sess_key[8],
 144                           DOM_CRED *sto_clnt_cred, DOM_CRED *rcv_srv_cred)
 145 {
 146         UTIME new_clnt_time;
 147         uint32 new_cred;
 148
 149         DEBUG(5,("clnt_deal_with_creds: %d\n", __LINE__));
 150
 151         /* increment client time by one second */
 152         new_clnt_time.time = sto_clnt_cred->timestamp.time + 1;
 153
 154         /* check that the received server credentials are valid */
 155         if (!cred_assert(&rcv_srv_cred->challenge, sess_key,
 156                          &sto_clnt_cred->challenge, new_clnt_time))
 157         {
 158                 return False;
 159         }
 160
 161         /* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
 162         new_cred = IVAL(sto_clnt_cred->challenge.data, 0);
 163         new_cred += new_clnt_time.time;
 164
 165         /* store new seed in client credentials */
 166         SIVAL(sto_clnt_cred->challenge.data, 0, new_cred);
 167
 168         DEBUG(5,("      new clnt cred: %s\n", credstr(sto_clnt_cred->challenge.data)));
 169         return True;
 170 }
 171
 172
 173 /****************************************************************************
 174   checks credentials; generates next step in the credential chain
 175 ****************************************************************************/
 176 BOOL deal_with_creds(uchar sess_key[8],
 177                      DOM_CRED *sto_clnt_cred,
 178                      DOM_CRED *rcv_clnt_cred, DOM_CRED *rtn_srv_cred)
 179 {
 180         UTIME new_clnt_time;
 181         uint32 new_cred;
 182
 183         DEBUG(5,("deal_with_creds: %d\n", __LINE__));
 184
 185         /* check that the received client credentials are valid */
 186         if (!cred_assert(&rcv_clnt_cred->challenge, sess_key,
 187                     &sto_clnt_cred->challenge, rcv_clnt_cred->timestamp))
 188         {
 189                 return False;
 190         }
 191
 192         /* increment client time by one second */
 193         new_clnt_time.time = rcv_clnt_cred->timestamp.time + 1;
 194
 195         /* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
 196         new_cred = IVAL(sto_clnt_cred->challenge.data, 0);
 197         new_cred += new_clnt_time.time;
 198
 199         DEBUG(5,("deal_with_creds: new_cred[0]=%x\n", new_cred));
 200
 201         /* doesn't matter that server time is 0 */
 202         rtn_srv_cred->timestamp.time = 0;
 203
 204         DEBUG(5,("deal_with_creds: new_clnt_time=%x\n", new_clnt_time.time));
 205
 206         /* create return credentials for inclusion in the reply */
 207         cred_create(sess_key, &sto_clnt_cred->challenge, new_clnt_time,
 208                     &rtn_srv_cred->challenge);
 209
 210         DEBUG(5,("deal_with_creds: clnt_cred=%s\n", credstr(sto_clnt_cred->challenge.data)));
 211
 212         /* store new seed in client credentials */
 213         SIVAL(sto_clnt_cred->challenge.data, 0, new_cred);
 214
 215         return True;
 216 }