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