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/* $OpenBSD: getrealm.c,v 1.9 1997/12/22 15:02:07 art Exp $ */
/* $KTH: getrealm.c,v 1.26 1997/10/08 22:51:13 joda Exp $ */
/*
* This software may now be redistributed outside the US.
*
*/
/*
* 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"
#define MATCH_SUBDOMAINS 0
/*
* krb_realmofhost.
* Given a fully-qualified domain-style primary host name,
* return the name of the Kerberos realm for the host.
* If the hostname contains no discernable domain, or an error occurs,
* return the local realm name, as supplied by get_krbrlm().
* If the hostname contains a domain, but no translation is found,
* the hostname's domain is converted to upper-case and returned.
*
* The format of each line of the translation file is:
* domain_name kerberos_realm
* -or-
* host_name kerberos_realm
*
* domain_name should be of the form .XXX.YYY (e.g. .LCS.MIT.EDU)
* host names should be in the usual form (e.g. FOO.BAR.BAZ)
*/
/* To automagically find the correct realm of a host (without
* krb.realms) add a text record for your domain with the name of your
* realm, like this:
*
* krb4-realm IN TXT FOO.SE
*
* The search is recursive, so you can also add entries for specific
* hosts. To find the realm of host a.b.c, it first tries
* krb4-realm.a.b.c, then krb4-realm.b.c and so on.
*/
static int
dns_find_realm(char *hostname, char *realm)
{
char domain[MAXHOSTNAMELEN + sizeof("krb4-realm..")];
char *p;
int level = 0;
struct dns_reply *r;
p = hostname;
while(1){
snprintf(domain, sizeof(domain), "krb4-realm.%s.", p);
p = strchr(p, '.');
if(p == NULL)
break;
p++;
r = dns_lookup(domain, "TXT");
if(r){
struct resource_record *rr = r->head;
while(rr){
if(rr->type == T_TXT){
strncpy(realm, rr->u.txt, REALM_SZ);
realm[REALM_SZ - 1] = 0;
dns_free_data(r);
return level;
}
rr = rr->next;
}
dns_free_data(r);
}
level++;
}
return -1;
}
static FILE *
open_krb_realms(void)
{
int i;
char file[128];
FILE *res;
for(i = 0; krb_get_krbrealms(i, file, sizeof(file)) == 0; i++)
if ((res = fopen(file, "r")) != NULL)
return res;
return NULL;
}
static int
file_find_realm(const char *phost, const char *domain,
char *ret_realm, size_t ret_realm_sz)
{
FILE *trans_file;
char buf[1024];
int ret = -1;
if ((trans_file = open_krb_realms()) == NULL)
return -1;
while (fgets(buf, sizeof(buf), trans_file) != NULL) {
char *save = NULL;
char *tok;
char *tmp_host;
char *tmp_realm;
tok = strtok_r(buf, " \t\r\n", &save);
if(tok == NULL)
continue;
tmp_host = tok;
tok = strtok_r(NULL, " \t\r\n", &save);
if(tok == NULL)
continue;
tmp_realm = tok;
if (strcasecmp(tmp_host, phost) == 0) {
/* exact match of hostname, so return the realm */
strncpy(ret_realm, tmp_realm, ret_realm_sz);
ret_realm[ret_realm_sz - 1] = '\0';
ret = 0;
break;
}
if ((tmp_host[0] == '.') && domain) {
const char *cp = domain;
do {
if(strcasecmp(tmp_host, domain) == 0){
/* domain match, save for later */
strncpy(ret_realm, tmp_realm, ret_realm_sz);
ret_realm[ret_realm_sz - 1] = '\0';
ret = 0;
break;
}
cp = strchr(cp + 1, '.');
} while(MATCH_SUBDOMAINS && cp);
}
}
fclose(trans_file);
return ret;
}
char *
krb_realmofhost(const char *host)
{
static char ret_realm[REALM_SZ];
char *domain;
char phost[MAXHOSTNAMELEN];
krb_name_to_name(host, phost, sizeof(phost));
domain = strchr(phost, '.');
if(file_find_realm(phost, domain, ret_realm, sizeof(ret_realm)) == 0)
return ret_realm;
if(dns_find_realm(phost, ret_realm) >= 0)
return ret_realm;
if (domain) {
char *cp;
strncpy(ret_realm, &domain[1], REALM_SZ);
ret_realm[REALM_SZ - 1] = 0;
/* Upper-case realm */
for (cp = ret_realm; *cp; cp++)
*cp = toupper(*cp);
} else {
krb_get_lrealm(ret_realm, 1);
}
return ret_realm;
}
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