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
|
/*
*
* Copyright 1989 by the Massachusetts Institute of Technology.
*
* For copying and distribution information, please see the file
* <mit-copyright.h>.
*
* Simple UDP-based server application. For demonstration.
* This program performs no useful function.
*/
#include "sample.h"
RCSID("$Id: simple_server.c,v 1.11 1999/11/13 06:29:24 assar Exp $");
static void
usage (void)
{
fprintf (stderr, "Usage: %s [-p port] [-s service] [-t srvtab]\n",
__progname);
exit (1);
}
int
main(int argc, char **argv)
{
char service[SNAME_SZ];
char instance[INST_SZ];
int port;
char srvtab[MaxPathLen];
struct sockaddr_in addr, otheraddr;
int c;
int sock;
int i;
int len;
KTEXT_ST k;
KTEXT ktxt = &k;
AUTH_DAT ad;
MSG_DAT msg_data;
des_key_schedule sched;
set_progname (argv[0]);
strlcpy (service, SAMPLE_SERVICE, sizeof(service));
strlcpy (instance, "*", sizeof(instance));
*srvtab = '\0';
port = 0;
while ((c = getopt (argc, argv, "p:s:t:")) != -1)
switch (c) {
case 'p' : {
struct servent *sp;
sp = getservbyname (optarg, "udp");
if (sp)
port = sp->s_port;
else
port = htons(atoi(optarg));
break;
}
case 's' :
strlcpy (service, optarg, sizeof(service));
break;
case 't' :
strlcpy (srvtab, optarg, sizeof(srvtab));
break;
case '?' :
default :
usage ();
}
if(port == 0)
port = k_getportbyname (SAMPLE_SERVICE, "udp", htons(SAMPLE_PORT));
memset (&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = port;
sock = socket (AF_INET, SOCK_DGRAM, 0);
if (sock < 0)
err (1, "socket");
if (bind (sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
err (1, "bind");
/* GET KRB_MK_REQ MESSAGE */
i = read(sock, ktxt->dat, MAX_KTXT_LEN);
if (i < 0)
err (1, "read");
printf("Received %d bytes\n", i);
ktxt->length = i;
/* Check authentication info */
i = krb_rd_req(ktxt, service, instance, 0, &ad, "");
if (i != KSUCCESS)
errx (1, "krb_rd_req: %s", krb_get_err_text(i));
printf("Got authentication info from %s%s%s@%s\n", ad.pname,
*ad.pinst ? "." : "", ad.pinst, ad.prealm);
/* GET KRB_MK_SAFE MESSAGE */
/* use "recvfrom" so we know client's address */
len = sizeof(otheraddr);
i = recvfrom(sock, ktxt->dat, MAX_KTXT_LEN, 0,
(struct sockaddr *)&otheraddr, &len);
if (i < 0)
err (1, "recvfrom");
printf("Received %d bytes\n", i);
/* Verify the checksummed message */
i = krb_rd_safe(ktxt->dat, i, &ad.session, &otheraddr,
&addr, &msg_data);
if (i != KSUCCESS)
errx (1, "krb_rd_safe: %s", krb_get_err_text(i));
printf("Safe message is: %s\n", msg_data.app_data);
/* NOW GET ENCRYPTED MESSAGE */
#ifdef NOENCRYPTION
memset(sched, 0, sizeof(sched));
#else
/* need key schedule for session key */
des_key_sched(&ad.session, sched);
#endif
/* use "recvfrom" so we know client's address */
len = sizeof(otheraddr);
i = recvfrom(sock, ktxt->dat, MAX_KTXT_LEN, 0,
(struct sockaddr *)&otheraddr, &len);
if (i < 0)
err (1, "recvfrom");
printf("Received %d bytes\n", i);
i = krb_rd_priv(ktxt->dat, i, sched, &ad.session, &otheraddr,
&addr, &msg_data);
if (i != KSUCCESS)
errx (1, "krb_rd_priv: %s", krb_get_err_text(i));
printf("Decrypted message is: %s\n", msg_data.app_data);
return(0);
}
|
