1/*
2 * Copyright (c) 1995, 1996, 1997 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *      This product includes software developed by the Kungliga Tekniska
20 *      H�gskolan and its contributors.
21 *
22 * 4. Neither the name of the Institute nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#include "sasl_mac_krb_locl.h"
40
41RCSID("$Id: rd_priv.c,v 1.4 2005/01/10 19:10:47 snsimon Exp $");
42
43/* application include files */
44#include "krb-archaeology.h"
45
46/*
47 * krb_rd_priv() decrypts and checks the integrity of an
48 * AUTH_MSG_PRIVATE message.  Given the message received, "in",
49 * the length of that message, "in_length", the key "schedule"
50 * and "key", and the network addresses of the
51 * "sender" and "receiver" of the message, krb_rd_safe() returns
52 * RD_AP_OK if the message is okay, otherwise some error code.
53 *
54 * The message data retrieved from "in" are returned in the structure
55 * "m_data".  The pointer to the application data
56 * (m_data->app_data) refers back to the appropriate place in "in".
57 *
58 * See the file "mk_priv.c" for the format of the AUTH_MSG_PRIVATE
59 * message.  The structure containing the extracted message
60 * information, MSG_DAT, is defined in "krb.h".
61 */
62
63int32_t
64krb_rd_priv(void *in, u_int32_t in_length,
65	    struct des_ks_struct *schedule, des_cblock *key,
66	    struct sockaddr_in *sender, struct sockaddr_in *receiver,
67	    MSG_DAT *m_data)
68{
69    unsigned char *p = (unsigned char*)in;
70    int little_endian;
71    u_int32_t clen;
72    struct timeval tv;
73    u_int32_t src_addr;
74    int delta_t;
75
76    unsigned char pvno, type;
77
78    pvno = *p++;
79    if(pvno != KRB_PROT_VERSION)
80	return RD_AP_VERSION;
81
82    type = *p++;
83    little_endian = type & 1;
84    type &= ~1;
85
86    p += krb_get_int(p, &clen, 4, little_endian);
87
88    if(clen + 2 > in_length)
89	return RD_AP_MODIFIED;
90
91    des_pcbc_encrypt((des_cblock*)p, (des_cblock*)p, clen,
92		     schedule, key, DES_DECRYPT);
93
94    p += krb_get_int(p, &m_data->app_length, 4, little_endian);
95    if(m_data->app_length + 17 > in_length)
96	return RD_AP_MODIFIED;
97
98    m_data->app_data = p;
99    p += m_data->app_length;
100
101    m_data->time_5ms = *p++;
102
103    p += krb_get_address(p, &src_addr);
104
105    if (!krb_equiv(src_addr, sender->sin_addr.s_addr))
106	return RD_AP_BADD;
107
108    p += krb_get_int(p, (u_int32_t *)&m_data->time_sec, 4, little_endian);
109
110    m_data->time_sec = lsb_time(m_data->time_sec, sender, receiver);
111
112    gettimeofday(&tv, NULL);
113
114    /* check the time integrity of the msg */
115    delta_t = abs((int)((long) tv.tv_sec - m_data->time_sec));
116    if (delta_t > CLOCK_SKEW)
117	return RD_AP_TIME;
118    if (krb_debug)
119	krb_warning("delta_t = %d\n", (int) delta_t);
120
121    /*
122     * caller must check timestamps for proper order and
123     * replays, since server might have multiple clients
124     * each with its own timestamps and we don't assume
125     * tightly synchronized clocks.
126     */
127
128    return KSUCCESS;
129}
130