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
|
/* $OpenBSD: read_service_key.c,v 1.6 1998/02/25 15:51:35 art Exp $ */
/* $KTH: read_service_key.c,v 1.8 1997/03/23 03:53:16 joda Exp $ */
/*
* This source code is no longer held under any constraint of USA
* `cryptographic laws' since it was exported legally. The cryptographic
* functions were removed from the code and a "Bones" distribution was
* made. A Commodity Jurisdiction Request #012-94 was filed with the
* USA State Department, who handed it to the Commerce department. The
* code was determined to fall under General License GTDA under ECCN 5D96G,
* and hence exportable. The cryptographic interfaces were re-added by Eric
* Young, and then KTH proceeded to maintain the code in the free world.
*
*/
/*
* Copyright (C) 1989 by the Massachusetts Institute of Technology
*
* Export of this software from the United States of America is assumed
* to 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. 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.
*
*/
#include "krb_locl.h"
/*
* The private keys for servers on a given host are stored in a
* "srvtab" file (typically "/etc/srvtab"). This routine extracts
* a given server's key from the file.
*
* read_service_key() takes the server's name ("service"), "instance",
* and "realm" and a key version number "kvno", and looks in the given
* "file" for the corresponding entry, and if found, returns the entry's
* key field in "key".
*
* If "instance" contains the string "*", then it will match
* any instance, and the chosen instance will be copied to that
* string. For this reason it is important that the there is enough
* space beyond the "*" to receive the entry.
*
* If "kvno" is 0, it is treated as a wild card and the first
* matching entry regardless of the "vno" field is returned.
*
* This routine returns KSUCCESS on success, otherwise KFAILURE.
*
* The format of each "srvtab" entry is as follows:
*
* Size Variable Field in file
* ---- -------- -------------
* string serv server name
* string inst server instance
* string realm server realm
* 1 byte vno server key version #
* 8 bytes key server's key
* ... ... ...
*/
int
read_service_key(char *service, /* Service Name */
char *instance, /* Instance name or "*" */
char *realm, /* Realm */
int kvno, /* Key version number */
char *file, /* Filename */
char *key) /* Pointer to key to be filled in */
{
char serv[SNAME_SZ];
char inst[INST_SZ];
char rlm[REALM_SZ];
unsigned char vno; /* Key version number */
int wcard;
int stab;
if ((stab = open(file, O_RDONLY, 0)) < 0)
return KFAILURE;
if (instance == NULL)
return KFAILURE;
wcard = (instance[0] == '*') && (instance[1] == '\0');
while (getst(stab, serv, SNAME_SZ) > 0) { /* Read sname */
getst(stab, inst, INST_SZ); /* Instance */
getst(stab, rlm, REALM_SZ); /* Realm */
/* Vers number */
if (read(stab, &vno, 1) != 1) {
close(stab);
return KFAILURE;
}
/* Key */
if (read(stab, key, 8) != 8) {
close(stab);
return KFAILURE;
}
/* Is this the right service */
if (service != NULL && strcmp(serv, service))
continue;
/* How about instance */
if (wcard == '\0' && strcmp(inst,instance))
continue;
if (wcard != 0) {
strncpy(instance, inst, INST_SZ);
instance[INST_SZ - 1] = '\0';
}
/* Is this the right realm */
if (realm != NULL && strcmp(rlm, realm))
continue;
/* How about the key version number */
if (kvno && kvno != (int) vno)
continue;
close(stab);
return KSUCCESS;
}
/* Can't find the requested service */
close(stab);
return(KFAILURE);
}
|
