1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/* $OpenBSD: rd_safe.c,v 1.4 1997/12/09 07:57:34 art Exp $ */
/* $KTH: rd_safe.c,v 1.24 1997/04/19 23:18:20 joda Exp $ */
/*
* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Kungliga Tekniska
* Högskolan and its contributors.
*
* 4. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb_locl.h"
/* application include files */
#include "lsb_addr_comp.h"
/* Generate two checksums in the given byteorder of the data, one
* new-form and one old-form. It has to be done this way to be
* compatible with the old version of des_quad_cksum.
*/
/* des_quad_chsum-type; 0 == unknown, 1 == new PL10++, 2 == old */
int dqc_type = DES_QUAD_DEFAULT;
void
fixup_quad_cksum(void *start, size_t len, des_cblock *key,
void *new_checksum, void *old_checksum, int little)
{
if (old_checksum == NULL || new_checksum == NULL)
return;
des_quad_cksum((des_cblock*)start, (des_cblock*)new_checksum, len, 2, key);
if(HOST_BYTE_ORDER){
if(little){
memcpy(old_checksum, new_checksum, 16);
}else{
u_int32_t *tmp = (u_int32_t*)new_checksum;
memcpy(old_checksum, new_checksum, 16);
swap_u_16(old_checksum);
swap_u_long(tmp[0]);
swap_u_long(tmp[1]);
swap_u_long(tmp[2]);
swap_u_long(tmp[3]);
}
}else{
if(little){
u_int32_t *tmp = (u_int32_t*)new_checksum;
swap_u_long(tmp[0]);
swap_u_long(tmp[1]);
swap_u_long(tmp[2]);
swap_u_long(tmp[3]);
memcpy(old_checksum, new_checksum, 16);
}else{
u_int32_t tmp[4];
tmp[0] = ((u_int32_t*)new_checksum)[3];
tmp[1] = ((u_int32_t*)new_checksum)[2];
tmp[2] = ((u_int32_t*)new_checksum)[1];
tmp[3] = ((u_int32_t*)new_checksum)[0];
memcpy(old_checksum, tmp, 16);
}
}
}
/*
* krb_rd_safe() checks the integrity of an AUTH_MSG_SAFE message.
* Given the message received, "in", the length of that message,
* "in_length", the "key" to compute the checksum with, and the
* network addresses of the "sender" and "receiver" of the message,
* krb_rd_safe() returns RD_AP_OK if message is okay, otherwise
* some error code.
*
* The message data retrieved from "in" is returned in the structure
* "m_data". The pointer to the application data (m_data->app_data)
* refers back to the appropriate place in "in".
*
* See the file "mk_safe.c" for the format of the AUTH_MSG_SAFE
* message. The structure containing the extracted message
* information, MSG_DAT, is defined in "krb.h".
*/
int32_t
krb_rd_safe(void *in, u_int32_t in_length, des_cblock *key,
struct sockaddr_in *sender, struct sockaddr_in *receiver,
MSG_DAT *m_data)
{
unsigned char *p = (unsigned char*)in, *start;
unsigned char pvno, type;
int little_endian;
struct timeval tv;
u_int32_t src_addr;
int delta_t;
if (p == NULL)
return KFAILURE;
pvno = *p++;
if(pvno != KRB_PROT_VERSION)
return RD_AP_VERSION;
type = *p++;
little_endian = type & 1;
type &= ~1;
if(type != AUTH_MSG_SAFE)
return RD_AP_MSG_TYPE;
start = p;
p += krb_get_int(p, &m_data->app_length, 4, little_endian);
if(m_data->app_length + 31 > in_length)
return RD_AP_MODIFIED;
m_data->app_data = p;
p += m_data->app_length;
m_data->time_5ms = *p++;
p += krb_get_address(p, &src_addr);
if (!krb_equiv(src_addr, sender->sin_addr.s_addr))
return RD_AP_BADD;
p += krb_get_int(p, (u_int32_t *)&m_data->time_sec, 4, little_endian);
m_data->time_sec = lsb_time(m_data->time_sec, sender, receiver);
gettimeofday(&tv, NULL);
delta_t = abs((int)((long) tv.tv_sec - m_data->time_sec));
if (delta_t > CLOCK_SKEW) return RD_AP_TIME;
/*
* caller must check timestamps for proper order and replays, since
* server might have multiple clients each with its own timestamps
* and we don't assume tightly synchronized clocks.
*/
{
unsigned char new_checksum[16];
unsigned char old_checksum[16];
fixup_quad_cksum(start, p - start, key,
new_checksum, old_checksum, little_endian);
if((dqc_type == DES_QUAD_GUESS || dqc_type == DES_QUAD_NEW) &&
memcmp(new_checksum, p, 16) == 0)
dqc_type = DES_QUAD_NEW;
else if((dqc_type == DES_QUAD_GUESS || dqc_type == DES_QUAD_OLD) &&
memcmp(old_checksum, p, 16) == 0)
dqc_type = DES_QUAD_OLD;
else
return RD_AP_MODIFIED;
}
return KSUCCESS;
}
|
