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/*
* Copyright 1985, 1986, 1987, 1988 by the Massachusetts Institute
* of Technology.
* For copying and distribution information, please see the file
* <Copyright.MIT>.
*
* from: _service_key.c,v 4.10 90/03/10 19:06:56 jon Exp $
* $FreeBSD$
*/
#if 0
#ifndef lint
static char *rcsid =
"$FreeBSD$";
#endif /* lint */
#endif
#include <krb.h>
#include <stdio.h>
#include <unistd.h>
#include <strings.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
* ... ... ...
*/
/*ARGSUSED */
int
read_service_key(service,instance,realm,kvno,file,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, open();
if ((stab = open(file, 0, 0)) < NULL)
return(KFAILURE);
wcard = (instance[0] == '*') && (instance[1] == '\0');
while(getst(stab,serv,SNAME_SZ) > 0) { /* Read sname */
(void) getst(stab,inst,INST_SZ); /* Instance */
(void) getst(stab,rlm,REALM_SZ); /* Realm */
/* Vers number */
if (read(stab,(char *)&vno,1) != 1) {
close(stab);
return(KFAILURE);
}
/* Key */
if (read(stab,key,8) != 8) {
close(stab);
return(KFAILURE);
}
/* Is this the right service */
if (strcmp(serv,service))
continue;
/* How about instance */
if (!wcard && strcmp(inst,instance))
continue;
if (wcard)
(void) strncpy(instance,inst,INST_SZ);
/* Is this the right realm */
#ifdef ATHENA_COMPAT
/* XXX For backward compatibility: if keyfile says "Athena"
and caller wants "ATHENA.MIT.EDU", call it a match */
if (strcmp(rlm,realm) &&
(strcmp(rlm,"Athena") ||
strcmp(realm,"ATHENA.MIT.EDU")))
continue;
#else /* ! ATHENA_COMPAT */
if (strcmp(rlm,realm))
continue;
#endif /* ATHENA_COMPAT */
/* How about the key version number */
if (kvno && kvno != (int) vno)
continue;
(void) close(stab);
return(KSUCCESS);
}
/* Can't find the requested service */
(void) close(stab);
return(KFAILURE);
}
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