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
|
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* kdc/dispatch.c
*
* Copyright 1990, 2009 by the Massachusetts Institute of Technology.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* Dispatch an incoming packet.
*/
#include "k5-int.h"
#include <syslog.h>
#include "kdc_util.h"
#include "extern.h"
#include "adm_proto.h"
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
static krb5_int32 last_usec = 0, last_os_random = 0;
static krb5_error_code make_too_big_error (krb5_data **out);
krb5_error_code
dispatch(void *cb, struct sockaddr *local_saddr, const krb5_fulladdr *from,
krb5_data *pkt, krb5_data **response, int is_tcp)
{
krb5_error_code retval;
krb5_kdc_req *as_req;
krb5_int32 now, now_usec;
/* decode incoming packet, and dispatch */
#ifndef NOCACHE
/* try the replay lookaside buffer */
if (kdc_check_lookaside(pkt, response)) {
/* a hit! */
const char *name = 0;
char buf[46];
if (is_tcp == 0 && (*response)->length > max_dgram_reply_size)
goto too_big_for_udp;
name = inet_ntop (ADDRTYPE2FAMILY (from->address->addrtype),
from->address->contents, buf, sizeof (buf));
if (name == 0)
name = "[unknown address type]";
krb5_klog_syslog(LOG_INFO,
"DISPATCH: repeated (retransmitted?) request from %s, resending previous response",
name);
return 0;
}
#endif
retval = krb5_crypto_us_timeofday(&now, &now_usec);
if (retval == 0) {
krb5_int32 usec_difference = now_usec-last_usec;
krb5_data data;
if(last_os_random == 0)
last_os_random = now;
/* Grab random data from OS every hour*/
if(now-last_os_random >= 60*60) {
krb5_c_random_os_entropy(kdc_context, 0, NULL);
last_os_random = now;
}
data.length = sizeof(krb5_int32);
data.data = (void *) &usec_difference;
krb5_c_random_add_entropy(kdc_context,
KRB5_C_RANDSOURCE_TIMING, &data);
last_usec = now_usec;
}
/* try TGS_REQ first; they are more common! */
if (krb5_is_tgs_req(pkt)) {
retval = process_tgs_req(pkt, from, response);
} else if (krb5_is_as_req(pkt)) {
if (!(retval = decode_krb5_as_req(pkt, &as_req))) {
/*
* setup_server_realm() sets up the global realm-specific data
* pointer.
* process_as_req frees the request if it is called
*/
if (!(retval = setup_server_realm(as_req->server))) {
retval = process_as_req(as_req, pkt, from, response);
}
else krb5_free_kdc_req(kdc_context, as_req);
}
}
else
retval = KRB5KRB_AP_ERR_MSG_TYPE;
#ifndef NOCACHE
/* put the response into the lookaside buffer */
if (!retval && *response != NULL)
kdc_insert_lookaside(pkt, *response);
#endif
if (is_tcp == 0 && (*response)->length > max_dgram_reply_size) {
too_big_for_udp:
krb5_free_data(kdc_context, *response);
retval = make_too_big_error(response);
if (retval) {
krb5_klog_syslog(LOG_ERR,
"error constructing KRB_ERR_RESPONSE_TOO_BIG error: %s",
error_message(retval));
}
}
return retval;
}
static krb5_error_code
make_too_big_error (krb5_data **out)
{
krb5_error errpkt;
krb5_error_code retval;
krb5_data *scratch;
*out = NULL;
memset(&errpkt, 0, sizeof(errpkt));
retval = krb5_us_timeofday(kdc_context, &errpkt.stime, &errpkt.susec);
if (retval)
return retval;
errpkt.error = KRB_ERR_RESPONSE_TOO_BIG;
errpkt.server = tgs_server;
errpkt.client = NULL;
errpkt.text.length = 0;
errpkt.text.data = 0;
errpkt.e_data.length = 0;
errpkt.e_data.data = 0;
scratch = malloc(sizeof(*scratch));
if (scratch == NULL)
return ENOMEM;
retval = krb5_mk_error(kdc_context, &errpkt, scratch);
if (retval) {
free(scratch);
return retval;
}
*out = scratch;
return 0;
}
|
