kdb_default.c revision 2
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* lib/kdb/kdb_helper.c
*
* Copyright 1995, 2009 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.
*
*/
/*
* Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
*/
#include "k5-int.h"
#include "kdb.h"
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <arpa/inet.h>
#include <libintl.h> /* Solaris Kerberos */
/*
* Given a particular enctype and optional salttype and kvno, find the
* most appropriate krb5_key_data entry of the database entry.
*
* If stype or kvno is negative, it is ignored.
* If kvno is 0 get the key which is maxkvno for the princ and matches
* the other attributes.
*/
krb5_error_code
krb5_dbe_def_search_enctype(kcontext, dbentp, start, ktype, stype, kvno, kdatap)
krb5_context kcontext;
krb5_db_entry *dbentp;
krb5_int32 *start;
krb5_int32 ktype;
krb5_int32 stype;
krb5_int32 kvno;
krb5_key_data **kdatap;
{
int i, idx;
int maxkvno;
krb5_key_data *datap;
krb5_error_code ret;
krb5_boolean saw_non_permitted = FALSE;
ret = 0;
if (kvno == -1 && stype == -1 && ktype == -1)
kvno = 0;
if (kvno == 0) {
/* Get the max key version */
for (i = 0; i < dbentp->n_key_data; i++) {
if (kvno < dbentp->key_data[i].key_data_kvno) {
kvno = dbentp->key_data[i].key_data_kvno;
}
}
}
maxkvno = -1;
datap = (krb5_key_data *) NULL;
for (i = *start; i < dbentp->n_key_data; i++) {
krb5_boolean similar;
krb5_int32 db_stype;
ret = 0;
if (dbentp->key_data[i].key_data_ver > 1) {
db_stype = dbentp->key_data[i].key_data_type[1];
} else {
db_stype = KRB5_KDB_SALTTYPE_NORMAL;
}
/* Match this entry against the arguments. */
if (ktype != -1) {
if ((ret = krb5_c_enctype_compare(kcontext, (krb5_enctype) ktype,
dbentp->key_data[i].key_data_type[0],
&similar)))
return(ret);
if (!similar)
continue;
}
if (stype >= 0 && db_stype != stype)
continue;
if (kvno >= 0 && dbentp->key_data[i].key_data_kvno != kvno)
continue;
/* Filter out non-permitted enctypes. */
if (!krb5_is_permitted_enctype(kcontext,
dbentp->key_data[i].key_data_type[0])) {
saw_non_permitted = TRUE;
continue;
}
if (dbentp->key_data[i].key_data_kvno > maxkvno) {
maxkvno = dbentp->key_data[i].key_data_kvno;
datap = &dbentp->key_data[i];
idx = i;
}
}
/* If we scanned the whole set of keys and matched only non-permitted
* enctypes, indicate that. */
if (maxkvno < 0 && *start == 0 && saw_non_permitted)
ret = KRB5_KDB_NO_PERMITTED_KEY;
if (maxkvno < 0)
return ret ? ret : KRB5_KDB_NO_MATCHING_KEY;
*kdatap = datap;
*start = idx+1;
return 0;
}
/*
* kdb default functions. Ideally, some other file should have this functions. For now, TBD.
*/
#ifndef min
#define min(a,b) (((a) < (b)) ? (a) : (b))
#endif
krb5_error_code
krb5_def_store_mkey_list(krb5_context context,
char *keyfile,
krb5_principal mname,
krb5_keylist_node *keylist,
char *master_pwd)
{
krb5_error_code retval = 0;
char defkeyfile[MAXPATHLEN+1];
char *tmp_ktname = NULL, *tmp_ktpath;
krb5_data *realm = krb5_princ_realm(context, mname);
krb5_keytab kt = NULL;
krb5_keytab_entry new_entry;
struct stat stb;
int statrc;
if (!keyfile) {
(void) snprintf(defkeyfile, sizeof(defkeyfile), "%s%s",
DEFAULT_KEYFILE_STUB, realm->data);
keyfile = defkeyfile;
}
/*
* XXX making the assumption that the keyfile is in a dir that requires root
* privilege to write to thus making timing attacks unlikely.
*/
if ((statrc = stat(keyfile, &stb)) >= 0) {
/* if keyfile exists it better be a regular file */
if (!S_ISREG(stb.st_mode)) {
retval = EINVAL;
krb5_set_error_message (context, retval,
gettext("keyfile (%s) is not a regular file: %s"),
keyfile, error_message(retval));
goto out;
}
}
/* Use temp keytab file name in case creation of keytab fails */
/* create temp file template for use by mktemp() */
if ((retval = asprintf(&tmp_ktname, "WRFILE:%s_XXXXXX", keyfile)) < 0) {
krb5_set_error_message (context, retval,
"Could not create temp keytab file name.");
goto out;
}
/*
* Set tmp_ktpath to point to the keyfile path (skip WRFILE:). Subtracting
* 1 to account for NULL terminator in sizeof calculation of a string
* constant. Used further down.
*/
tmp_ktpath = tmp_ktname + (sizeof("WRFILE:") - 1);
if (mktemp(tmp_ktpath) == NULL) {
retval = errno;
krb5_set_error_message (context, retval,
"Could not create temp stash file: %s",
error_message(errno));
goto out;
}
/* create new stash keytab using temp file name */
retval = krb5_kt_resolve(context, tmp_ktname, &kt);
if (retval != 0)
goto out;
while (keylist && !retval) {
memset(&new_entry, 0, sizeof(new_entry));
new_entry.principal = mname;
new_entry.key = keylist->keyblock;
new_entry.vno = keylist->kvno;
retval = krb5_kt_add_entry(context, kt, &new_entry);
keylist = keylist->next;
}
krb5_kt_close(context, kt);
if (retval != 0) {
/* delete tmp keyfile if it exists and an error occurrs */
if (stat(keyfile, &stb) >= 0)
(void) unlink(tmp_ktpath);
} else {
/* rename original keyfile to original filename */
if (rename(tmp_ktpath, keyfile) < 0) {
retval = errno;
krb5_set_error_message (context, retval,
"rename of temporary keyfile (%s) to (%s) failed: %s",
tmp_ktpath, keyfile, error_message(errno));
}
}
out:
if (tmp_ktname != NULL)
free(tmp_ktname);
return retval;
}
krb5_error_code
krb5_def_store_mkey(krb5_context context,
char *keyfile,
krb5_principal mname,
krb5_kvno kvno,
krb5_keyblock *key,
char *master_pwd)
{
krb5_keylist_node list;
list.kvno = kvno;
list.keyblock = *key;
list.next = NULL;
return krb5_def_store_mkey_list(context, keyfile, mname, &list,
master_pwd);
}
static krb5_error_code
krb5_db_def_fetch_mkey_stash(krb5_context context,
const char *keyfile,
krb5_keyblock *key,
krb5_kvno *kvno)
{
krb5_error_code retval = 0;
krb5_ui_2 enctype;
krb5_ui_4 keylength;
FILE *kf = NULL;
#ifdef ANSI_STDIO
if (!(kf = fopen(keyfile, "rb")))
#else
if (!(kf = fopen(keyfile, "r")))
#endif
return KRB5_KDB_CANTREAD_STORED;
set_cloexec_file(kf);
if (fread((krb5_pointer) &enctype, 2, 1, kf) != 1) {
retval = KRB5_KDB_CANTREAD_STORED;
goto errout;
}
#if BIG_ENDIAN_MASTER_KEY
enctype = ntohs((uint16_t) enctype);
#endif
if (key->enctype == ENCTYPE_UNKNOWN)
key->enctype = enctype;
else if (enctype != key->enctype) {
retval = KRB5_KDB_BADSTORED_MKEY;
goto errout;
}
if (fread((krb5_pointer) &keylength,
sizeof(keylength), 1, kf) != 1) {
retval = KRB5_KDB_CANTREAD_STORED;
goto errout;
}
#if BIG_ENDIAN_MASTER_KEY
key->length = ntohl((uint32_t) keylength);
#else
key->length = keylength;
#endif
if (!key->length || ((int) key->length) < 0) {
retval = KRB5_KDB_BADSTORED_MKEY;
goto errout;
}
if (!(key->contents = (krb5_octet *)malloc(key->length))) {
retval = ENOMEM;
goto errout;
}
if (fread((krb5_pointer) key->contents, sizeof(key->contents[0]),
key->length, kf) != key->length) {
retval = KRB5_KDB_CANTREAD_STORED;
zap(key->contents, key->length);
free(key->contents);
key->contents = 0;
} else
retval = 0;
/*
* Note, the old stash format did not store the kvno and at this point it
* can be assumed to be 1 as is the case for the mkey princ. If the kvno is
* passed in and isn't ignore_vno just leave it alone as this could cause
* verifcation trouble if the mkey princ is using a kvno other than 1.
*/
if (kvno && *kvno == IGNORE_VNO)
*kvno = 1;
errout:
(void) fclose(kf);
return retval;
}
static krb5_error_code
krb5_db_def_fetch_mkey_keytab(krb5_context context,
const char *keyfile,
krb5_principal mname,
krb5_keyblock *key,
krb5_kvno *kvno)
{
krb5_error_code retval = 0;
krb5_keytab kt = NULL;
krb5_keytab_entry kt_ent;
krb5_enctype enctype = IGNORE_ENCTYPE;
if ((retval = krb5_kt_resolve(context, keyfile, &kt)) != 0)
goto errout;
/* override default */
if (key->enctype != ENCTYPE_UNKNOWN)
enctype = key->enctype;
if ((retval = krb5_kt_get_entry(context, kt, mname,
kvno ? *kvno : IGNORE_VNO,
enctype,
&kt_ent)) == 0) {
if (key->enctype == ENCTYPE_UNKNOWN)
key->enctype = kt_ent.key.enctype;
if (((int) kt_ent.key.length) < 0) {
retval = KRB5_KDB_BADSTORED_MKEY;
krb5_kt_free_entry(context, &kt_ent);
goto errout;
}
key->length = kt_ent.key.length;
/*
* If a kvno pointer was passed in and it dereferences the
* IGNORE_VNO value then it should be assigned the value of the kvno
* found in the keytab otherwise the KNVO specified should be the
* same as the one returned from the keytab.
*/
if (kvno != NULL && *kvno == IGNORE_VNO)
*kvno = kt_ent.vno;
/*
* kt_ent will be free'd so need to allocate and copy key contents for
* output to caller.
*/
if (!(key->contents = (krb5_octet *)malloc(key->length))) {
retval = ENOMEM;
krb5_kt_free_entry(context, &kt_ent);
goto errout;
}
memcpy(key->contents, kt_ent.key.contents, kt_ent.key.length);
krb5_kt_free_entry(context, &kt_ent);
}
errout:
if (kt)
krb5_kt_close(context, kt);
return retval;
}
krb5_error_code
krb5_db_def_fetch_mkey(krb5_context context,
krb5_principal mname,
krb5_keyblock *key,
krb5_kvno *kvno,
char *db_args)
{
krb5_error_code retval;
char keyfile[MAXPATHLEN+1];
krb5_data *realm = krb5_princ_realm(context, mname);
key->magic = KV5M_KEYBLOCK;
if (db_args != NULL) {
(void) strncpy(keyfile, db_args, sizeof(keyfile));
} else {
(void) snprintf(keyfile, sizeof(keyfile), "%s%s",
DEFAULT_KEYFILE_STUB, realm->data);
}
/* null terminate no matter what */
keyfile[sizeof(keyfile) - 1] = '\0';
/* Try the keytab and old stash file formats. */
retval = krb5_db_def_fetch_mkey_keytab(context, keyfile, mname, key, kvno);
if (retval == KRB5_KEYTAB_BADVNO)
retval = krb5_db_def_fetch_mkey_stash(context, keyfile, key, kvno);
/*
* Use a generic error code for failure to retrieve the master
* key, but set a message indicating the actual error.
*/
if (retval != 0) {
krb5_set_error_message(context, KRB5_KDB_CANTREAD_STORED,
"Can not fetch master key (error: %s).",
error_message(retval));
return KRB5_KDB_CANTREAD_STORED;
} else
return 0;
}
/*
* Note, this verifies that the input mkey is currently protecting all the mkeys
*/
krb5_error_code
krb5_def_verify_master_key(krb5_context context,
krb5_principal mprinc,
krb5_kvno kvno,
krb5_keyblock *mkey)
{
krb5_error_code retval;
krb5_db_entry master_entry;
int nprinc;
krb5_boolean more;
krb5_keyblock tempkey;
nprinc = 1;
if ((retval = krb5_db_get_principal(context, mprinc,
&master_entry, &nprinc, &more)))
return(retval);
if (nprinc != 1) {
if (nprinc)
krb5_db_free_principal(context, &master_entry, nprinc);
return(KRB5_KDB_NOMASTERKEY);
} else if (more) {
krb5_db_free_principal(context, &master_entry, nprinc);
return(KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE);
}
if ((retval = krb5_dbekd_decrypt_key_data(context, mkey,
&master_entry.key_data[0],
&tempkey, NULL))) {
krb5_db_free_principal(context, &master_entry, nprinc);
return retval;
}
if (mkey->length != tempkey.length ||
memcmp((char *)mkey->contents,
(char *)tempkey.contents,mkey->length)) {
retval = KRB5_KDB_BADMASTERKEY;
}
if (kvno != IGNORE_VNO &&
kvno != (krb5_kvno) master_entry.key_data->key_data_kvno) {
retval = KRB5_KDB_BADMASTERKEY;
krb5_set_error_message (context, retval,
"User specified mkeyVNO (%u) does not match master key princ's KVNO (%u)",
kvno, master_entry.key_data->key_data_kvno);
}
zap((char *)tempkey.contents, tempkey.length);
free(tempkey.contents);
krb5_db_free_principal(context, &master_entry, nprinc);
return retval;
}
/* Solaris Kerberos: removed unused mkvno arg */
krb5_error_code
krb5_def_fetch_mkey_list(krb5_context context,
krb5_principal mprinc,
const krb5_keyblock *mkey,
krb5_keylist_node **mkeys_list)
{
krb5_error_code retval;
krb5_db_entry master_entry;
int nprinc;
krb5_boolean more, found_key = FALSE;
krb5_keyblock cur_mkey;
krb5_keylist_node *mkey_list_head = NULL, **mkey_list_node;
krb5_key_data *key_data;
krb5_mkey_aux_node *mkey_aux_data_list = NULL, *aux_data_entry;
int i;
if (mkeys_list == NULL)
return (EINVAL);
memset(&cur_mkey, 0, sizeof(cur_mkey));
memset(&master_entry, 0, sizeof(master_entry));
nprinc = 1;
if ((retval = krb5_db_get_principal(context, mprinc,
&master_entry, &nprinc, &more)))
return (retval);
if (nprinc != 1) {
if (nprinc)
krb5_db_free_principal(context, &master_entry, nprinc);
return(KRB5_KDB_NOMASTERKEY);
} else if (more) {
krb5_db_free_principal(context, &master_entry, nprinc);
return (KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE);
}
/*
* Check if the input mkey is the latest key and if it isn't then find the
* latest mkey.
*/
if (mkey->enctype == master_entry.key_data[0].key_data_type[0]) {
if (krb5_dbekd_decrypt_key_data(context, mkey,
&master_entry.key_data[0],
&cur_mkey, NULL) == 0) {
found_key = TRUE;
}
}
if (!found_key) {
if ((retval = krb5_dbe_lookup_mkey_aux(context, &master_entry,
&mkey_aux_data_list)))
goto clean_n_exit;
for (aux_data_entry = mkey_aux_data_list; aux_data_entry != NULL;
aux_data_entry = aux_data_entry->next) {
if (krb5_dbekd_decrypt_key_data(context, mkey,
&aux_data_entry->latest_mkey,
&cur_mkey, NULL) == 0) {
found_key = TRUE;
break;
}
}
if (found_key != TRUE) {
krb5_set_error_message (context, KRB5_KDB_BADMASTERKEY,
"Unable to decrypt latest master key with the provided master key\n");
retval = KRB5_KDB_BADMASTERKEY;
goto clean_n_exit;
}
}
/*
* Extract all the mkeys from master_entry using the most current mkey and
* create a mkey list for the mkeys field in kdc_realm_t.
*/
mkey_list_head = (krb5_keylist_node *) malloc(sizeof(krb5_keylist_node));
if (mkey_list_head == NULL) {
retval = ENOMEM;
goto clean_n_exit;
}
memset(mkey_list_head, 0, sizeof(krb5_keylist_node));
/* loop through any other master keys creating a list of krb5_keylist_nodes */
mkey_list_node = &mkey_list_head->next;
for (i = 1; i < master_entry.n_key_data; i++) {
if (*mkey_list_node == NULL) {
/* *mkey_list_node points to next field of previous node */
*mkey_list_node = (krb5_keylist_node *) malloc(sizeof(krb5_keylist_node));
if (*mkey_list_node == NULL) {
retval = ENOMEM;
goto clean_n_exit;
}
memset(*mkey_list_node, 0, sizeof(krb5_keylist_node));
}
key_data = &master_entry.key_data[i];
retval = krb5_dbekd_decrypt_key_data(context, &cur_mkey,
key_data,
&((*mkey_list_node)->keyblock),
NULL);
if (retval)
goto clean_n_exit;
(*mkey_list_node)->kvno = key_data->key_data_kvno;
mkey_list_node = &((*mkey_list_node)->next);
}
/*
* Solaris Kerberos: moved this part down because we cache derived keys in
* the cur_mkey block during the krb5_dbekd_decrypt_key_data() above so the
* latest version of cur_mkey should be copied to mkey_list_head->keyblock
* so it has those derived keys.
*/
/* Set mkey_list_head to the current mkey as an optimization. */
/* mkvno may not be latest so ... */
mkey_list_head->kvno = master_entry.key_data[0].key_data_kvno;
/* this is the latest clear mkey (avoids a redundant decrypt) */
mkey_list_head->keyblock = cur_mkey;
*mkeys_list = mkey_list_head;
clean_n_exit:
krb5_db_free_principal(context, &master_entry, nprinc);
krb5_dbe_free_mkey_aux_list(context, mkey_aux_data_list);
if (retval != 0) {
/*
* Solaris Kerberos: derived key caching changes. If retval != 0 then
* mkey_list_head->keyblock hasn't been set so just free mkey_list_head
* and maybe free cur_mkey separately.
*/
if (mkey_list_head != NULL) {
krb5_dbe_free_key_list(context, mkey_list_head->next);
krb5_xfree(mkey_list_head);
}
if (found_key == TRUE)
krb5_free_keyblock_contents(context, &cur_mkey);
}
return retval;
}
krb5_error_code kdb_def_set_mkey ( krb5_context kcontext,
char *pwd,
krb5_keyblock *key )
{
/* printf("default set master key\n"); */
return 0;
}
krb5_error_code kdb_def_get_mkey ( krb5_context kcontext,
krb5_keyblock **key )
{
/* printf("default get master key\n"); */
return 0;
}
krb5_error_code kdb_def_set_mkey_list ( krb5_context kcontext,
krb5_keylist_node *keylist )
{
/* printf("default set master key\n"); */
return 0;
}
krb5_error_code kdb_def_get_mkey_list ( krb5_context kcontext,
krb5_keylist_node **keylist )
{
/* printf("default get master key\n"); */
return 0;
}
krb5_error_code krb5_def_promote_db (krb5_context kcontext,
char *s, char **args)
{
/* printf("default promote_db\n"); */
return KRB5_PLUGIN_OP_NOTSUPP;
}