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
   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 extern int DEBUGLEVEL;
  25
  26
  27
  28 /****************************************************************************
  29 represent a credential as a string
  30 ****************************************************************************/
  31 char *credstr(uchar *cred)
  32 {
  33         static fstring buf;
  34         sprintf(buf,"%02X%02X%02X%02X%02X%02X%02X%02X",
  35                 cred[0], cred[1], cred[2], cred[3],
  36                 cred[4], cred[5], cred[6], cred[7]);
  37         return buf;
  38 }
  39
  40
  41 /****************************************************************************
  42   setup the session key.
  43 Input: 8 byte challenge block
  44        8 byte server challenge block
  45       16 byte md4 encrypted password
  46 Output:
  47       8 byte session key
  48 ****************************************************************************/
  49 void cred_session_key(DOM_CHAL *clnt_chal, DOM_CHAL *srv_chal, char *pass,
  50                       uchar session_key[8])
  51 {
  52         uint32 sum[2];
  53         unsigned char sum2[8];
  54
  55         sum[0] = IVAL(clnt_chal->data, 0) + IVAL(srv_chal->data, 0);
  56         sum[1] = IVAL(clnt_chal->data, 4) + IVAL(srv_chal->data, 4);
  57
  58         SIVAL(sum2,0,sum[0]);
  59         SIVAL(sum2,4,sum[1]);
  60
  61         cred_hash1(session_key, sum2,(unsigned char *)pass);
  62
  63         /* debug output */
  64         DEBUG(4,("cred_session_key\n"));
  65
  66         DEBUG(5,("      clnt_chal: %s\n", credstr(clnt_chal->data)));
  67         DEBUG(5,("      srv_chal : %s\n", credstr(srv_chal->data)));
  68         DEBUG(5,("      clnt+srv : %s\n", credstr(sum2)));
  69         DEBUG(5,("      sess_key : %s\n", credstr(session_key)));
  70 }
  71
  72
  73 /****************************************************************************
  74 create a credential
  75
  76 Input:
  77       8 byte sesssion key
  78       8 byte stored credential
  79       4 byte timestamp
  80
  81 Output:
  82       8 byte credential
  83 ****************************************************************************/
  84 void cred_create(uchar session_key[8], DOM_CHAL *stor_cred, UTIME timestamp,
  85                  DOM_CHAL *cred)
  86 {
  87         DOM_CHAL time_cred;
  88
  89         SIVAL(time_cred.data, 0, IVAL(stor_cred->data, 0) + timestamp.time);
  90         SIVAL(time_cred.data, 4, IVAL(stor_cred->data, 4));
  91
  92         cred_hash2(cred->data, time_cred.data, session_key);
  93
  94         /* debug output*/
  95         DEBUG(4,("cred_create\n"));
  96
  97         DEBUG(5,("      sess_key : %s\n", credstr(session_key)));
  98         DEBUG(5,("      stor_cred: %s\n", credstr(stor_cred->data)));
  99         DEBUG(5,("      timestamp: %lx\n"    , timestamp.time));
 100         DEBUG(5,("      timecred : %s\n", credstr(time_cred.data)));
 101         DEBUG(5,("      calc_cred: %s\n", credstr(cred->data)));
 102 }
 103
 104
 105 /****************************************************************************
 106   check a supplied credential
 107
 108 Input:
 109       8 byte received credential
 110       8 byte sesssion key
 111       8 byte stored credential
 112       4 byte timestamp
 113
 114 Output:
 115       returns 1 if computed credential matches received credential
 116       returns 0 otherwise
 117 ****************************************************************************/
 118 int cred_assert(DOM_CHAL *cred, char session_key[8], DOM_CHAL *stored_cred,
 119                 UTIME timestamp)
 120 {
 121         DOM_CHAL cred2;
 122
 123         cred_create(session_key, stored_cred, timestamp, &cred2);
 124
 125         /* debug output*/
 126         DEBUG(4,("cred_assert\n"));
 127
 128         DEBUG(5,("      challenge : %s\n", credstr(cred->data)));
 129         DEBUG(5,("      calculated: %s\n", credstr(cred2.data)));
 130
 131         if (memcmp(cred->data, cred2.data, 8) == 0)
 132         {
 133                 DEBUG(5, ("credentials check ok\n"));
 134                 return True;
 135         }
 136         else
 137         {
 138                 DEBUG(5, ("credentials check wrong\n"));
 139                 return False;
 140         }
 141 }
 142
 143
 144 /****************************************************************************
 145   checks credentials; generates next step in the credential chain
 146 ****************************************************************************/
 147 BOOL clnt_deal_with_creds(char sess_key[8],
 148                           DOM_CRED *sto_clnt_cred, DOM_CRED *rcv_srv_cred)
 149 {
 150         UTIME new_clnt_time;
 151         uint32 new_cred;
 152
 153         DEBUG(5,("clnt_deal_with_creds: %d\n", __LINE__));
 154
 155         /* increment client time by one second */
 156         new_clnt_time.time = sto_clnt_cred->timestamp.time + 1;
 157
 158         /* check that the received server credentials are valid */
 159         if (!cred_assert(&(rcv_srv_cred->challenge), sess_key,
 160                          &(sto_clnt_cred->challenge), new_clnt_time))
 161         {
 162                 return False;
 163         }
 164
 165         /* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
 166         new_cred = IVAL(sto_clnt_cred->challenge.data, 0);
 167         new_cred += new_clnt_time.time;
 168
 169         /* store new seed in client credentials */
 170         SIVAL(sto_clnt_cred->challenge.data, 0, new_cred);
 171
 172         DEBUG(5,("      new clnt cred: %s\n", credstr(sto_clnt_cred->challenge.data)));
 173         return True;
 174 }
 175
 176
 177 /****************************************************************************
 178   checks credentials; generates next step in the credential chain
 179 ****************************************************************************/
 180 BOOL deal_with_creds(uchar sess_key[8],
 181                      DOM_CRED *sto_clnt_cred,
 182                      DOM_CRED *rcv_clnt_cred, DOM_CRED *rtn_srv_cred)
 183 {
 184         UTIME new_clnt_time;
 185         uint32 new_cred;
 186
 187         DEBUG(5,("deal_with_creds: %d\n", __LINE__));
 188
 189         /* check that the received client credentials are valid */
 190         if (!cred_assert(&(rcv_clnt_cred->challenge), sess_key,
 191                     &(sto_clnt_cred->challenge), rcv_clnt_cred->timestamp))
 192         {
 193                 return False;
 194         }
 195
 196         /* increment client time by one second */
 197         new_clnt_time.time = rcv_clnt_cred->timestamp.time + 1;
 198
 199         /* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
 200         new_cred = IVAL(sto_clnt_cred->challenge.data, 0);
 201         new_cred += new_clnt_time.time;
 202
 203         DEBUG(5,("deal_with_creds: new_cred[0]=%lx\n", new_cred));
 204
 205         /* doesn't matter that server time is 0 */
 206         rtn_srv_cred->timestamp.time = 0;
 207
 208         DEBUG(5,("deal_with_creds: new_clnt_time=%lx\n", new_clnt_time.time));
 209
 210         /* create return credentials for inclusion in the reply */
 211         cred_create(sess_key, &(sto_clnt_cred->challenge), new_clnt_time,
 212                     &(rtn_srv_cred->challenge));
 213
 214         DEBUG(5,("deal_with_creds: clnt_cred=%s\n", credstr(sto_clnt_cred->challenge.data)));
 215
 216         /* store new seed in client credentials */
 217         SIVAL(sto_clnt_cred->challenge.data, 0, new_cred);
 218
 219         return True;
 220 }
 221
 222