/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/kdb/keytab.c */
/*
* Copyright 1995 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.
*/
#include <string.h>
#include "k5-int.h"
#include "kdb_kt.h"
static int
is_xrealm_tgt(krb5_context, krb5_const_principal);
krb5_error_code krb5_ktkdb_close (krb5_context, krb5_keytab);
krb5_error_code krb5_ktkdb_get_entry (krb5_context, krb5_keytab, krb5_const_principal,
krb5_kvno, krb5_enctype, krb5_keytab_entry *);
static krb5_error_code
krb5_ktkdb_get_name(krb5_context context, krb5_keytab keytab,
char *name, unsigned int namelen)
{
if (strlcpy(name, "KDB:", namelen) >= namelen)
return KRB5_KT_NAME_TOOLONG;
return 0;
}
krb5_kt_ops krb5_kt_kdb_ops = {
0,
"KDB", /* Prefix -- this string should not appear anywhere else! */
krb5_ktkdb_resolve, /* resolve */
krb5_ktkdb_get_name, /* get_name */
krb5_ktkdb_close, /* close */
krb5_ktkdb_get_entry, /* get */
NULL, /* start_seq_get */
NULL, /* get_next */
NULL, /* end_get */
NULL, /* add (extended) */
NULL, /* remove (extended) */
};
typedef struct krb5_ktkdb_data {
char * name;
} krb5_ktkdb_data;
krb5_error_code
krb5_db_register_keytab(krb5_context context)
{
return krb5_kt_register(context, &krb5_kt_kdb_ops);
}
krb5_error_code
krb5_ktkdb_resolve(context, name, id)
krb5_context context;
const char * name;
krb5_keytab * id;
{
if ((*id = (krb5_keytab) malloc(sizeof(**id))) == NULL)
return(ENOMEM);
(*id)->ops = &krb5_kt_kdb_ops;
(*id)->magic = KV5M_KEYTAB;
return(0);
}
krb5_error_code
krb5_ktkdb_close(context, kt)
krb5_context context;
krb5_keytab kt;
{
/*
* This routine is responsible for freeing all memory allocated
* for this keytab. There are no system resources that need
* to be freed nor are there any open files.
*
* This routine should undo anything done by krb5_ktkdb_resolve().
*/
kt->ops = NULL;
free(kt);
return 0;
}
static krb5_context ktkdb_ctx = NULL;
/*
* Set a different context for use with ktkdb_get_entry(). This is
* primarily useful for kadmind, where the gssapi library context,
* which will be used for the keytab, will necessarily have a
* different context than that used by the kadm5 library to access the
* database for its own purposes.
*/
krb5_error_code
krb5_ktkdb_set_context(krb5_context ctx)
{
ktkdb_ctx = ctx;
return 0;
}
krb5_error_code
krb5_ktkdb_get_entry(in_context, id, principal, kvno, enctype, entry)
krb5_context in_context;
krb5_keytab id;
krb5_const_principal principal;
krb5_kvno kvno;
krb5_enctype enctype;
krb5_keytab_entry * entry;
{
krb5_context context;
krb5_error_code kerror = 0;
krb5_key_data * key_data;
krb5_db_entry * db_entry;
int xrealm_tgt;
krb5_boolean similar;
if (ktkdb_ctx)
context = ktkdb_ctx;
else
context = in_context;
xrealm_tgt = is_xrealm_tgt(context, principal);
/* Check whether database is inited. Open is commented */
if ((kerror = krb5_db_inited(context)))
return(kerror);
/* get_principal */
kerror = krb5_db_get_principal(context, principal, 0, &db_entry);
if (kerror == KRB5_KDB_NOENTRY)
return(KRB5_KT_NOTFOUND);
if (kerror)
return(kerror);
if (db_entry->attributes & KRB5_KDB_DISALLOW_SVR
|| db_entry->attributes & KRB5_KDB_DISALLOW_ALL_TIX) {
kerror = KRB5_KT_NOTFOUND;
goto error;
}
/* match key */
/* For cross realm tgts, we match whatever enctype is provided;
* for other principals, we only match the first enctype that is
* found. Since the TGS and AS code do the same thing, then we
* will only successfully decrypt tickets we have issued.*/
kerror = krb5_dbe_find_enctype(context, db_entry,
xrealm_tgt?enctype:-1,
-1, kvno, &key_data);
if (kerror == KRB5_KDB_NO_MATCHING_KEY)
kerror = KRB5_KT_KVNONOTFOUND;
if (kerror)
goto error;
kerror = krb5_dbe_decrypt_key_data(context, NULL, key_data,
&entry->key, NULL);
if (kerror)
goto error;
if (enctype > 0) {
kerror = krb5_c_enctype_compare(context, enctype,
entry->key.enctype, &similar);
if (kerror)
goto error;
if (!similar) {
kerror = KRB5_KDB_NO_PERMITTED_KEY;
goto error;
}
}
/*
* Coerce the enctype of the output keyblock in case we got an
* inexact match on the enctype.
*/
entry->key.enctype = enctype;
kerror = krb5_copy_principal(context, principal, &entry->principal);
if (kerror)
goto error;
/* Close database */
error:
krb5_db_free_principal(context, db_entry);
/* krb5_db_close_database(context); */
return(kerror);
}
/*
* is_xrealm_tgt: Returns true if the principal is a cross-realm TGT
* principal-- a principal with first component krbtgt and second
* component not equal to realm.
*/
static int
is_xrealm_tgt(krb5_context context, krb5_const_principal princ)
{
krb5_data *dat;
if (krb5_princ_size(context, princ) != 2)
return 0;
dat = krb5_princ_component(context, princ, 0);
if (strncmp("krbtgt", dat->data, dat->length) != 0)
return 0;
dat = krb5_princ_component(context, princ, 1);
if (dat->length != princ->realm.length)
return 1;
if (strncmp(dat->data, princ->realm.data, dat->length) == 0)
return 0;
return 1;
}