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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/os/sn2princ.c */
/*
* Copyright 1991,2002 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* 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.
*/
/* Convert a hostname and service name to a principal in the "standard"
* form. */
#include "k5-int.h"
#include "os-proto.h"
#include "fake-addrinfo.h"
#include <ctype.h>
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#if !defined(DEFAULT_RDNS_LOOKUP)
#define DEFAULT_RDNS_LOOKUP 1
#endif
static krb5_boolean
use_reverse_dns(krb5_context context)
{
krb5_error_code ret;
int value;
ret = profile_get_boolean(context->profile, KRB5_CONF_LIBDEFAULTS,
KRB5_CONF_RDNS, NULL, DEFAULT_RDNS_LOOKUP,
&value);
if (ret)
return DEFAULT_RDNS_LOOKUP;
return value;
}
/* Set *name_out to the canonicalized form of name, obeying relevant
* configuration settings. The caller must free the result. */
static krb5_error_code
canon_hostname(krb5_context context, krb5_int32 type, const char *host,
char **canonhost_out)
{
struct addrinfo *ai = NULL, hint;
char namebuf[NI_MAXHOST], *copy, *p;
int err;
const char *canonhost;
*canonhost_out = NULL;
canonhost = host;
if (type == KRB5_NT_SRV_HST && context->dns_canonicalize_hostname) {
/* Try a forward lookup of the hostname. */
memset(&hint, 0, sizeof(hint));
hint.ai_flags = AI_CANONNAME;
err = getaddrinfo(host, 0, &hint, &ai);
if (err == EAI_MEMORY)
goto cleanup;
if (!err && ai->ai_canonname != NULL)
canonhost = ai->ai_canonname;
if (!err && use_reverse_dns(context)) {
/* Try a reverse lookup of the address. */
err = getnameinfo(ai->ai_addr, ai->ai_addrlen, namebuf,
sizeof(namebuf), NULL, 0, NI_NAMEREQD);
if (err == EAI_MEMORY)
goto cleanup;
if (!err)
canonhost = namebuf;
}
}
copy = strdup(canonhost);
if (copy == NULL)
goto cleanup;
if (type == KRB5_NT_SRV_HST) {
/* Convert the hostname to lower case. */
for (p = copy; *p != '\0'; p++) {
if (isupper((unsigned char)*p))
*p = tolower((unsigned char)*p);
}
}
/* Remove any trailing dot. */
if (copy[0] != '\0') {
p = copy + strlen(copy) - 1;
if (*p == '.')
*p = '\0';
}
*canonhost_out = copy;
cleanup:
/* We only return success or ENOMEM. */
if (ai != NULL)
freeaddrinfo(ai);
return (*canonhost_out == NULL) ? ENOMEM : 0;
}
/* If hostname appears to have a :port or :instance trailer (used in MSSQLSvc
* principals), return a pointer to the separator. Otherwise return NULL. */
static const char *
find_trailer(const char *hostname)
{
const char *p = strchr(hostname, ':');
/* Look for a single colon followed by one or more characters. An IPv6
* address will have more than one colon, so don't accept that. */
if (p == NULL || p[1] == '\0' || strchr(p + 1, ':') != NULL)
return NULL;
return p;
}
krb5_error_code KRB5_CALLCONV
krb5_sname_to_principal(krb5_context context, const char *hostname,
const char *sname, krb5_int32 type,
krb5_principal *princ_out)
{
krb5_error_code ret;
krb5_principal princ;
const char *realm, *trailer;
char **hrealms = NULL, *canonhost = NULL, *hostonly = NULL, *concat = NULL;
char localname[MAXHOSTNAMELEN];
*princ_out = NULL;
if (type != KRB5_NT_UNKNOWN && type != KRB5_NT_SRV_HST)
return KRB5_SNAME_UNSUPP_NAMETYPE;
/* If hostname is NULL, use the local hostname. */
if (hostname == NULL) {
if (gethostname(localname, MAXHOSTNAMELEN) != 0)
return SOCKET_ERRNO;
hostname = localname;
}
/* If sname is NULL, use "host". */
if (sname == NULL)
sname = "host";
/* If there is a trailer, remove it for now. */
trailer = find_trailer(hostname);
if (trailer != NULL) {
hostonly = k5memdup0(hostname, trailer - hostname, &ret);
if (hostonly == NULL)
goto cleanup;
hostname = hostonly;
}
/* Canonicalize the hostname if appropriate. */
ret = canon_hostname(context, type, hostname, &canonhost);
if (ret)
goto cleanup;
hostname = canonhost;
/* Find the realm of the host. */
ret = krb5_get_host_realm(context, hostname, &hrealms);
if (ret)
goto cleanup;
if (hrealms[0] == NULL) {
ret = KRB5_ERR_HOST_REALM_UNKNOWN;
goto cleanup;
}
realm = hrealms[0];
/* If there was a trailer, put it back on the end. */
if (trailer != NULL) {
if (asprintf(&concat, "%s%s", hostname, trailer) < 0) {
ret = ENOMEM;
goto cleanup;
}
hostname = concat;
}
ret = krb5_build_principal(context, &princ, strlen(realm), realm, sname,
hostname, (char *)NULL);
if (ret)
goto cleanup;
princ->type = type;
*princ_out = princ;
cleanup:
free(hostonly);
free(canonhost);
free(concat);
krb5_free_host_realm(context, hrealms);
return ret;
}
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