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/*
Unix SMB/CIFS implementation.
code to manipulate domain credentials
Copyright (C) Andrew Tridgell 1997-2003
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
/****************************************************************************
represent a credential as a string
****************************************************************************/
char *credstr(const uchar *cred)
{
static fstring buf;
slprintf(buf, sizeof(buf) - 1, "%02X%02X%02X%02X%02X%02X%02X%02X",
cred[0], cred[1], cred[2], cred[3],
cred[4], cred[5], cred[6], cred[7]);
return buf;
}
/****************************************************************************
setup the session key.
Input: 8 byte challenge block
8 byte server challenge block
16 byte md4 encrypted password
Output:
8 byte session key
****************************************************************************/
void cred_session_key(const struct netr_Credential *client_challenge,
const struct netr_Credential *server_challenge,
const uint8 md4_pass[16],
uint8 session_key[8])
{
uint32 sum[2];
uint8 sum2[8];
sum[0] = IVAL(client_challenge->data, 0) + IVAL(server_challenge->data, 0);
sum[1] = IVAL(client_challenge->data, 4) + IVAL(server_challenge->data, 4);
SIVAL(sum2,0,sum[0]);
SIVAL(sum2,4,sum[1]);
cred_hash1(session_key, sum2, md4_pass);
}
/****************************************************************************
create a credential
Input:
8 byte sesssion key
8 byte stored credential
4 byte timestamp
Output:
8 byte credential
****************************************************************************/
void cred_create(uchar session_key[8], struct netr_Credential *stor_cred, time_t timestamp,
struct netr_Credential *cred)
{
struct netr_Credential time_cred;
SIVAL(time_cred.data, 0, IVAL(stor_cred->data, 0) + timestamp);
SIVAL(time_cred.data, 4, IVAL(stor_cred->data, 4));
cred_hash2(cred->data, time_cred.data, session_key);
/* debug output*/
DEBUG(4,("cred_create\n"));
DEBUG(5,(" sess_key : %s\n", credstr(session_key)));
DEBUG(5,(" stor_cred: %s\n", credstr(stor_cred->data)));
DEBUG(5,(" timestamp: %x\n", (unsigned)timestamp));
DEBUG(5,(" timecred : %s\n", credstr(time_cred.data)));
DEBUG(5,(" calc_cred: %s\n", credstr(cred->data)));
}
/****************************************************************************
check a supplied credential
Input:
8 byte received credential
8 byte sesssion key
8 byte stored credential
4 byte timestamp
Output:
returns 1 if computed credential matches received credential
returns 0 otherwise
****************************************************************************/
int cred_assert(struct netr_Credential *cred, uchar session_key[8],
struct netr_Credential *stored_cred,
time_t timestamp)
{
struct netr_Credential cred2;
cred_create(session_key, stored_cred, timestamp, &cred2);
/* debug output*/
DEBUG(4,("cred_assert\n"));
DEBUG(5,(" challenge : %s\n", credstr(cred->data)));
DEBUG(5,(" calculated: %s\n", credstr(cred2.data)));
if (memcmp(cred->data, cred2.data, 8) == 0)
{
DEBUG(5, ("credentials check ok\n"));
return True;
}
else
{
DEBUG(5, ("credentials check wrong\n"));
return False;
}
}
/****************************************************************************
checks credentials; generates next step in the credential chain
****************************************************************************/
BOOL clnt_deal_with_creds(uchar sess_key[8],
struct netr_Authenticator *sto_clnt_cred,
struct netr_Authenticator *rcv_srv_cred)
{
time_t new_clnt_time;
uint32 new_cred;
/* increment client time by one second !?! */
new_clnt_time = sto_clnt_cred->timestamp + 1;
/* check that the received server credentials are valid */
if (!cred_assert(&rcv_srv_cred->cred, sess_key,
&sto_clnt_cred->cred, new_clnt_time)) {
return False;
}
/* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
new_cred = IVAL(sto_clnt_cred->cred.data, 0);
new_cred += new_clnt_time;
/* store new seed in client credentials */
SIVAL(sto_clnt_cred->cred.data, 0, new_cred);
return True;
}
/****************************************************************************
checks credentials; generates next step in the credential chain
****************************************************************************/
BOOL deal_with_creds(uchar sess_key[8],
struct netr_Authenticator *sto_clnt_cred,
struct netr_Authenticator *rcv_clnt_cred,
struct netr_Authenticator *rtn_srv_cred)
{
time_t new_clnt_time;
uint32 new_cred;
DEBUG(5,("deal_with_creds: %d\n", __LINE__));
/* check that the received client credentials are valid */
if (!cred_assert(&rcv_clnt_cred->cred, sess_key,
&sto_clnt_cred->cred, rcv_clnt_cred->timestamp))
{
return False;
}
/* increment client time by one second */
new_clnt_time = rcv_clnt_cred->timestamp + 1;
/* first 4 bytes of the new seed is old client 4 bytes + clnt time + 1 */
new_cred = IVAL(sto_clnt_cred->cred.data, 0);
new_cred += new_clnt_time;
DEBUG(5,("deal_with_creds: new_cred[0]=%x\n", new_cred));
/* doesn't matter that server time is 0 */
rtn_srv_cred->timestamp = 0;
DEBUG(5,("deal_with_creds: new_clnt_time=%x\n", (unsigned)new_clnt_time));
/* create return credentials for inclusion in the reply */
cred_create(sess_key, &sto_clnt_cred->cred, new_clnt_time,
&rtn_srv_cred->cred);
DEBUG(5,("deal_with_creds: clnt_cred=%s\n", credstr(sto_clnt_cred->cred.data)));
/* store new seed in client credentials */
SIVAL(sto_clnt_cred->cred.data, 0, new_cred);
return True;
}
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