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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/*
* Copyright (c) 1997 - 2003 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. 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 <krb5_locl.h>
RCSID("$Id: rd_safe.c 19827 2007-01-11 02:54:59Z lha $");
static krb5_error_code
verify_checksum(krb5_context context,
krb5_auth_context auth_context,
KRB_SAFE *safe)
{
krb5_error_code ret;
u_char *buf;
size_t buf_size;
size_t len;
Checksum c;
krb5_crypto crypto;
krb5_keyblock *key;
c = safe->cksum;
safe->cksum.cksumtype = 0;
safe->cksum.checksum.data = NULL;
safe->cksum.checksum.length = 0;
ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, safe, &len, ret);
if(ret)
return ret;
if(buf_size != len)
krb5_abortx(context, "internal error in ASN.1 encoder");
if (auth_context->remote_subkey)
key = auth_context->remote_subkey;
else if (auth_context->local_subkey)
key = auth_context->local_subkey;
else
key = auth_context->keyblock;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
goto out;
ret = krb5_verify_checksum (context,
crypto,
KRB5_KU_KRB_SAFE_CKSUM,
buf + buf_size - len,
len,
&c);
krb5_crypto_destroy(context, crypto);
out:
safe->cksum = c;
free (buf);
return ret;
}
krb5_error_code KRB5_LIB_FUNCTION
krb5_rd_safe(krb5_context context,
krb5_auth_context auth_context,
const krb5_data *inbuf,
krb5_data *outbuf,
krb5_replay_data *outdata)
{
krb5_error_code ret;
KRB_SAFE safe;
size_t len;
if (outbuf)
krb5_data_zero(outbuf);
if ((auth_context->flags &
(KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
outdata == NULL) {
krb5_set_error_string(context, "rd_safe: need outdata to return data");
return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
}
ret = decode_KRB_SAFE (inbuf->data, inbuf->length, &safe, &len);
if (ret)
return ret;
if (safe.pvno != 5) {
ret = KRB5KRB_AP_ERR_BADVERSION;
krb5_clear_error_string (context);
goto failure;
}
if (safe.msg_type != krb_safe) {
ret = KRB5KRB_AP_ERR_MSG_TYPE;
krb5_clear_error_string (context);
goto failure;
}
if (!krb5_checksum_is_keyed(context, safe.cksum.cksumtype)
|| !krb5_checksum_is_collision_proof(context, safe.cksum.cksumtype)) {
ret = KRB5KRB_AP_ERR_INAPP_CKSUM;
krb5_clear_error_string (context);
goto failure;
}
/* check sender address */
if (safe.safe_body.s_address
&& auth_context->remote_address
&& !krb5_address_compare (context,
auth_context->remote_address,
safe.safe_body.s_address)) {
ret = KRB5KRB_AP_ERR_BADADDR;
krb5_clear_error_string (context);
goto failure;
}
/* check receiver address */
if (safe.safe_body.r_address
&& auth_context->local_address
&& !krb5_address_compare (context,
auth_context->local_address,
safe.safe_body.r_address)) {
ret = KRB5KRB_AP_ERR_BADADDR;
krb5_clear_error_string (context);
goto failure;
}
/* check timestamp */
if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
krb5_timestamp sec;
krb5_timeofday (context, &sec);
if (safe.safe_body.timestamp == NULL ||
safe.safe_body.usec == NULL ||
abs(*safe.safe_body.timestamp - sec) > context->max_skew) {
ret = KRB5KRB_AP_ERR_SKEW;
krb5_clear_error_string (context);
goto failure;
}
}
/* XXX - check replay cache */
/* check sequence number. since MIT krb5 cannot generate a sequence
number of zero but instead generates no sequence number, we accept that
*/
if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
if ((safe.safe_body.seq_number == NULL
&& auth_context->remote_seqnumber != 0)
|| (safe.safe_body.seq_number != NULL
&& *safe.safe_body.seq_number !=
auth_context->remote_seqnumber)) {
ret = KRB5KRB_AP_ERR_BADORDER;
krb5_clear_error_string (context);
goto failure;
}
auth_context->remote_seqnumber++;
}
ret = verify_checksum (context, auth_context, &safe);
if (ret)
goto failure;
outbuf->length = safe.safe_body.user_data.length;
outbuf->data = malloc(outbuf->length);
if (outbuf->data == NULL && outbuf->length != 0) {
ret = ENOMEM;
krb5_set_error_string (context, "malloc: out of memory");
krb5_data_zero(outbuf);
goto failure;
}
memcpy (outbuf->data, safe.safe_body.user_data.data, outbuf->length);
if ((auth_context->flags &
(KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
/* if these fields are not present in the safe-part, silently
return zero */
memset(outdata, 0, sizeof(*outdata));
if(safe.safe_body.timestamp)
outdata->timestamp = *safe.safe_body.timestamp;
if(safe.safe_body.usec)
outdata->usec = *safe.safe_body.usec;
if(safe.safe_body.seq_number)
outdata->seq = *safe.safe_body.seq_number;
}
failure:
free_KRB_SAFE (&safe);
return ret;
}
|
