source3/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   setup the session key.
  27 Input: 8 byte challenge block
  28        8 byte server challenge block
  29       16 byte md4 encrypted password
  30 Output:
  31       8 byte session key
  32 ****************************************************************************/
  33 void cred_session_key(DOM_CHAL *clnt_chal, DOM_CHAL *srv_chal, char *pass,
  34                        uint32 session_key[2])
  35 {
  36         uint32 sum[2];
  37         unsigned char sum2[8];
  38         unsigned char netsesskey[8];
  39
  40         sum[0] = IVAL(clnt_chal->data, 0) + IVAL(srv_chal->data, 0);
  41         sum[1] = IVAL(clnt_chal->data, 4) + IVAL(srv_chal->data, 4);
  42
  43         SIVAL(sum2,0,sum[0]);
  44         SIVAL(sum2,4,sum[1]);
  45
  46         cred_hash1(netsesskey, sum2,(unsigned char *)pass);
  47
  48         session_key[0] = IVAL(netsesskey, 0);
  49         session_key[1] = IVAL(netsesskey, 4);
  50
  51         /* debug output */
  52         DEBUG(4,("cred_session_key\n"));
  53
  54         DEBUG(5,("      clnt_chal: %lx %lx\n", clnt_chal->data[0], clnt_chal->data[1]));
  55         DEBUG(5,("      srv_chal : %lx %lx\n", srv_chal ->data[0], srv_chal ->data[1]));
  56         DEBUG(5,("      clnt+srv : %lx %lx\n", sum            [0], sum            [1]));
  57         DEBUG(5,("      sess_key : %lx %lx\n", session_key    [0], session_key    [1]));
  58 }
  59
  60
  61 /****************************************************************************
  62 create a credential
  63
  64 Input:
  65       8 byte sesssion key
  66       8 byte stored credential
  67       4 byte timestamp
  68
  69 Output:
  70       8 byte credential
  71 ****************************************************************************/
  72 void cred_create(uint32 session_key[2], DOM_CHAL *stor_cred, UTIME timestamp,
  73                  DOM_CHAL *cred)
  74 {
  75         DOM_CHAL time_cred;
  76         unsigned char calc_cred[8];
  77         unsigned char timecred[8];
  78         unsigned char netsesskey[8];
  79
  80         SIVAL(netsesskey, 0, session_key[0]);
  81         SIVAL(netsesskey, 4, session_key[1]);
  82
  83         SIVAL(timecred, 0, IVAL(stor_cred, 0) + timestamp.time);
  84         SIVAL(timecred, 4, IVAL(stor_cred, 4));
  85
  86         cred_hash2(calc_cred, timecred, netsesskey);
  87
  88         cred->data[0] = IVAL(calc_cred, 0);
  89         cred->data[1] = IVAL(calc_cred, 4);
  90
  91         time_cred.data[0] = IVAL(timecred, 0);
  92         time_cred.data[1] = IVAL(timecred, 4);
  93
  94         /* debug output*/
  95         DEBUG(4,("cred_create\n"));
  96
  97         DEBUG(5,("      sess_key : %lx %lx\n", session_key    [0], session_key    [1]));
  98         DEBUG(5,("      stor_cred: %lx %lx\n", stor_cred->data[0], stor_cred->data[1]));
  99         DEBUG(5,("      timestamp: %lx\n"    , timestamp.time));
 100         DEBUG(5,("      timecred : %lx %lx\n", time_cred .data[0], time_cred .data[1]));
 101         DEBUG(5,("      calc_cred: %lx %lx\n", cred     ->data[0], cred     ->data[1]));
 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, uint32 session_key[2], 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 : %lx %lx\n", cred->data[0], cred->data[1]));
 129         DEBUG(5,("      calculated: %lx %lx\n", cred2.data[0], cred2.data[1]));
 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(uint32 sess_key[2],
 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: %lx %lx\n", sto_clnt_cred->challenge.data[0],
 173                                                sto_clnt_cred->challenge.data[1]));
 174         return True;
 175 }
 176
 177
 178 /****************************************************************************
 179   checks credentials; generates next step in the credential chain
 180 ****************************************************************************/
 181 BOOL deal_with_creds(uint32 sess_key[2],
 182                 DOM_CRED *sto_clnt_cred,
 183                 DOM_CRED *rcv_clnt_cred, DOM_CRED *rtn_srv_cred)
 184 {
 185         UTIME new_clnt_time;
 186         uint32 new_cred;
 187
 188         DEBUG(5,("deal_with_creds: %d\n", __LINE__));
 189
 190         /* check that the received client credentials are valid */
 191         if (!cred_assert(&(rcv_clnt_cred->challenge), sess_key,
 192                     &(sto_clnt_cred->challenge), rcv_clnt_cred->timestamp))
 193         {
 194                 return False;
 195         }
 196
 197         /* increment client time by one second */
 198         new_clnt_time.time = rcv_clnt_cred->timestamp.time + 1;
 199
 200         /* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
 201         new_cred = IVAL(sto_clnt_cred->challenge.data, 0);
 202         new_cred += new_clnt_time.time;
 203
 204         DEBUG(5,("deal_with_creds: new_cred[0]=%lx\n", new_cred));
 205
 206         /* doesn't matter that server time is 0 */
 207         rtn_srv_cred->timestamp.time = 0;
 208
 209         DEBUG(5,("deal_with_creds: new_clnt_time=%lx\n", new_clnt_time.time));
 210
 211         /* create return credentials for inclusion in the reply */
 212         cred_create(sess_key, &(sto_clnt_cred->challenge), new_clnt_time,
 213                     &(rtn_srv_cred->challenge));
 214
 215         DEBUG(5,("deal_with_creds: clnt_cred[0]=%lx\n",
 216                   sto_clnt_cred->challenge.data[0]));
 217
 218         /* store new seed in client credentials */
 219         SIVAL(sto_clnt_cred->challenge.data, 0, new_cred);
 220
 221         return True;
 222 }
 223
 224