/* $NetBSD: keys.c,v 1.4 2017/01/28 21:31:48 christos Exp $ */
/*
* Copyright (c) 1997 - 2011 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "hdb_locl.h"
struct hx509_certs_data;
struct krb5_pk_identity;
struct krb5_pk_cert;
struct ContentInfo;
struct AlgorithmIdentifier;
struct _krb5_krb_auth_data;
typedef struct krb5_pk_init_ctx_data *krb5_pk_init_ctx;
struct krb5_dh_moduli;
struct _krb5_key_data;
struct _krb5_encryption_type;
struct _krb5_key_type;
#include <krb5/pkinit_asn1.h>
#include <krb5/krb5-private.h>
#include <krb5/base64.h>
/*
* free all the memory used by (len, keys)
*/
void
hdb_free_keys(krb5_context context, int len, Key *keys)
{
size_t i;
for (i = 0; i < len; i++) {
free(keys[i].mkvno);
keys[i].mkvno = NULL;
if (keys[i].salt != NULL) {
free_Salt(keys[i].salt);
free(keys[i].salt);
keys[i].salt = NULL;
}
krb5_free_keyblock_contents(context, &keys[i].key);
}
free (keys);
}
/*
* for each entry in `default_keys' try to parse it as a sequence
* of etype:salttype:salt, syntax of this if something like:
* [(des|des3|etype):](pw-salt|afs3)[:string], if etype is omitted it
* means all etypes, and if string is omitted is means the default
* string (for that principal). Additional special values:
* v5 == pw-salt, and
* v4 == des:pw-salt:
* afs or afs3 == des:afs3-salt
*/
static const krb5_enctype des_etypes[] = {
KRB5_ENCTYPE_DES_CBC_MD5,
KRB5_ENCTYPE_DES_CBC_MD4,
KRB5_ENCTYPE_DES_CBC_CRC
};
static const krb5_enctype all_etypes[] = {
KRB5_ENCTYPE_AES256_CTS_HMAC_SHA1_96,
KRB5_ENCTYPE_DES3_CBC_SHA1,
KRB5_ENCTYPE_ARCFOUR_HMAC_MD5
};
static krb5_error_code
parse_key_set(krb5_context context, const char *key,
krb5_enctype **ret_enctypes, size_t *ret_num_enctypes,
krb5_salt *salt, krb5_principal principal)
{
const char *p;
char buf[3][256];
int num_buf = 0;
int i, num_enctypes = 0;
krb5_enctype e;
const krb5_enctype *enctypes = NULL;
krb5_error_code ret;
p = key;
*ret_enctypes = NULL;
*ret_num_enctypes = 0;
/* split p in a list of :-separated strings */
for(num_buf = 0; num_buf < 3; num_buf++)
if(strsep_copy(&p, ":", buf[num_buf], sizeof(buf[num_buf])) == -1)
break;
salt->saltvalue.data = NULL;
salt->saltvalue.length = 0;
for(i = 0; i < num_buf; i++) {
if(enctypes == NULL && num_buf > 1) {
/* this might be a etype specifier */
/* XXX there should be a string_to_etypes handling
special cases like `des' and `all' */
if(strcmp(buf[i], "des") == 0) {
enctypes = des_etypes;
num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
} else if(strcmp(buf[i], "des3") == 0) {
e = KRB5_ENCTYPE_DES3_CBC_SHA1;
enctypes = &e;
num_enctypes = 1;
} else {
ret = krb5_string_to_enctype(context, buf[i], &e);
if (ret == 0) {
enctypes = &e;
num_enctypes = 1;
} else
return ret;
}
continue;
}
if(salt->salttype == 0) {
/* interpret string as a salt specifier, if no etype
is set, this sets default values */
/* XXX should perhaps use string_to_salttype, but that
interface sucks */
if(strcmp(buf[i], "pw-salt") == 0) {
if(enctypes == NULL) {
enctypes = all_etypes;
num_enctypes = sizeof(all_etypes)/sizeof(all_etypes[0]);
}
salt->salttype = KRB5_PW_SALT;
} else if(strcmp(buf[i], "afs3-salt") == 0) {
if(enctypes == NULL) {
enctypes = des_etypes;
num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
}
salt->salttype = KRB5_AFS3_SALT;
}
continue;
}
if (salt->saltvalue.data != NULL)
free(salt->saltvalue.data);
/* if there is a final string, use it as the string to
salt with, this is mostly useful with null salt for
v4 compat, and a cell name for afs compat */
salt->saltvalue.data = strdup(buf[i]);
if (salt->saltvalue.data == NULL)
return krb5_enomem(context);
salt->saltvalue.length = strlen(buf[i]);
}
if(enctypes == NULL || salt->salttype == 0) {
krb5_free_salt(context, *salt);
krb5_set_error_message(context, EINVAL, "bad value for default_keys `%s'", key);
return EINVAL;
}
/* if no salt was specified make up default salt */
if(salt->saltvalue.data == NULL) {
if(salt->salttype == KRB5_PW_SALT) {
ret = krb5_get_pw_salt(context, principal, salt);
if (ret)
return ret;
} else if(salt->salttype == KRB5_AFS3_SALT) {
krb5_const_realm realm = krb5_principal_get_realm(context, principal);
salt->saltvalue.data = strdup(realm);
if(salt->saltvalue.data == NULL) {
krb5_set_error_message(context, ENOMEM,
"out of memory while "
"parsing salt specifiers");
return ENOMEM;
}
strlwr(salt->saltvalue.data);
salt->saltvalue.length = strlen(realm);
}
}
*ret_enctypes = malloc(sizeof(enctypes[0]) * num_enctypes);
if (*ret_enctypes == NULL) {
krb5_free_salt(context, *salt);
krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
return ENOMEM;
}
memcpy(*ret_enctypes, enctypes, sizeof(enctypes[0]) * num_enctypes);
*ret_num_enctypes = num_enctypes;
return 0;
}
/**
* This function prunes an HDB entry's keys that are too old to have been used
* to mint still valid tickets (based on the entry's maximum ticket lifetime).
*
* @param context Context
* @param entry HDB entry
*/
krb5_error_code
hdb_prune_keys(krb5_context context, hdb_entry *entry)
{
HDB_extension *ext;
HDB_Ext_KeySet *keys;
size_t nelem;
ext = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
if (ext == NULL)
return 0;
keys = &ext->data.u.hist_keys;
nelem = keys->len;
/* Optionally drop key history for keys older than now - max_life */
if (entry->max_life != NULL && nelem > 0
&& krb5_config_get_bool_default(context, NULL, FALSE,
"kadmin", "prune-key-history", NULL)) {
hdb_keyset *elem;
time_t ceiling = time(NULL) - *entry->max_life;
time_t keep_time = 0;
size_t i;
/*
* Compute most recent key timestamp that predates the current time
* by at least the entry's maximum ticket lifetime.
*/
for (i = 0; i < nelem; ++i) {
elem = &keys->val[i];
if (elem->set_time && *elem->set_time < ceiling
&& (keep_time == 0 || *elem->set_time > keep_time))
keep_time = *elem->set_time;
}
/* Drop obsolete entries */
if (keep_time) {
for (i = 0; i < nelem; /* see below */) {
elem = &keys->val[i];
if (elem->set_time && *elem->set_time < keep_time) {
remove_HDB_Ext_KeySet(keys, i);
/*
* Removing the i'th element shifts the tail down, continue
* at same index with reduced upper bound.
*/
--nelem;
continue;
}
++i;
}
}
}
return 0;
}
/**
* This function adds an HDB entry's current keyset to the entry's key
* history. The current keyset is left alone; the caller is responsible
* for freeing it.
*
* @param context Context
* @param entry HDB entry
*/
krb5_error_code
hdb_add_current_keys_to_history(krb5_context context, hdb_entry *entry)
{
krb5_boolean replace = FALSE;
krb5_error_code ret;
HDB_extension *ext;
HDB_Ext_KeySet *keys;
hdb_keyset newkeyset;
time_t newtime;
if (entry->keys.len == 0)
return 0; /* nothing to do */
ext = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
if (ext == NULL) {
replace = TRUE;
ext = calloc(1, sizeof (*ext));
if (ext == NULL)
return krb5_enomem(context);
ext->data.element = choice_HDB_extension_data_hist_keys;
}
keys = &ext->data.u.hist_keys;
ext->mandatory = FALSE;
/*
* Copy in newest old keyset
*/
ret = hdb_entry_get_pw_change_time(entry, &newtime);
if (ret)
goto out;
memset(&newkeyset, 0, sizeof(newkeyset));
newkeyset.keys = entry->keys;
newkeyset.kvno = entry->kvno;
newkeyset.set_time = &newtime;
ret = add_HDB_Ext_KeySet(keys, &newkeyset);
if (ret)
goto out;
if (replace) {
/* hdb_replace_extension() deep-copies ext; what a waste */
ret = hdb_replace_extension(context, entry, ext);
if (ret)
goto out;
}
ret = hdb_prune_keys(context, entry);
if (ret)
goto out;
out:
if (replace && ext) {
free_HDB_extension(ext);
free(ext);
}
return ret;
}
/**
* This function adds a key to an HDB entry's key history.
*
* @param context Context
* @param entry HDB entry
* @param kvno Key version number of the key to add to the history
* @param key The Key to add
*/
krb5_error_code
hdb_add_history_key(krb5_context context, hdb_entry *entry, krb5_kvno kvno, Key *key)
{
size_t i;
hdb_keyset keyset;
HDB_Ext_KeySet *hist_keys;
HDB_extension ext;
HDB_extension *extp;
krb5_error_code ret;
memset(&keyset, 0, sizeof (keyset));
memset(&ext, 0, sizeof (ext));
extp = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
if (extp == NULL) {
ext.data.element = choice_HDB_extension_data_hist_keys;
extp = &ext;
}
extp->mandatory = FALSE;
hist_keys = &extp->data.u.hist_keys;
for (i = 0; i < hist_keys->len; i++) {
if (hist_keys->val[i].kvno == kvno) {
ret = add_Keys(&hist_keys->val[i].keys, key);
goto out;
}
}
keyset.kvno = kvno;
ret = add_Keys(&keyset.keys, key);
if (ret)
goto out;
ret = add_HDB_Ext_KeySet(hist_keys, &keyset);
if (ret)
goto out;
if (extp == &ext) {
ret = hdb_replace_extension(context, entry, &ext);
if (ret)
goto out;
}
out:
free_hdb_keyset(&keyset);
free_HDB_extension(&ext);
return ret;
}
/**
* This function changes an hdb_entry's kvno, swapping the current key
* set with a historical keyset. If no historical keys are found then
* an error is returned (the caller can still set entry->kvno directly).
*
* @param context krb5_context
* @param new_kvno New kvno for the entry
* @param entry hdb_entry to modify
*/
krb5_error_code
hdb_change_kvno(krb5_context context, krb5_kvno new_kvno, hdb_entry *entry)
{
HDB_extension ext;
HDB_extension *extp;
hdb_keyset keyset;
HDB_Ext_KeySet *hist_keys;
size_t i;
int found = 0;
krb5_error_code ret;
if (entry->kvno == new_kvno)
return 0;
extp = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
if (extp == NULL) {
memset(&ext, 0, sizeof (ext));
ext.data.element = choice_HDB_extension_data_hist_keys;
extp = &ext;
}
memset(&keyset, 0, sizeof (keyset));
hist_keys = &extp->data.u.hist_keys;
for (i = 0; i < hist_keys->len; i++) {
if (hist_keys->val[i].kvno == new_kvno) {
found = 1;
ret = copy_hdb_keyset(&hist_keys->val[i], &keyset);
if (ret)
goto out;
ret = remove_HDB_Ext_KeySet(hist_keys, i);
if (ret)
goto out;
break;
}
}
if (!found)
return HDB_ERR_KVNO_NOT_FOUND;
ret = hdb_add_current_keys_to_history(context, entry);
if (ret)
goto out;
/* Note: we do nothing with keyset.set_time */
entry->kvno = new_kvno;
entry->keys = keyset.keys; /* shortcut */
memset(&keyset.keys, 0, sizeof (keyset.keys));
out:
free_hdb_keyset(&keyset);
return ret;
}
static krb5_error_code
add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
krb5_enctype enctype, krb5_salt *salt)
{
krb5_error_code ret;
Key key, *tmp;
memset(&key, 0, sizeof(key));
tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
if (tmp == NULL)
return ENOMEM;
*key_set = tmp;
key.key.keytype = enctype;
key.key.keyvalue.length = 0;
key.key.keyvalue.data = NULL;
if (salt) {
key.salt = calloc(1, sizeof(*key.salt));
if (key.salt == NULL) {
free_Key(&key);
return ENOMEM;
}
key.salt->type = salt->salttype;
krb5_data_zero (&key.salt->salt);
ret = krb5_data_copy(&key.salt->salt,
salt->saltvalue.data,
salt->saltvalue.length);
if (ret) {
free_Key(&key);
return ret;
}
} else
key.salt = NULL;
(*key_set)[*nkeyset] = key;
*nkeyset += 1;
return 0;
}
static
krb5_error_code
ks_tuple2str(krb5_context context, int n_ks_tuple,
krb5_key_salt_tuple *ks_tuple, char ***ks_tuple_strs)
{
size_t i;
char **ksnames;
krb5_error_code rc = KRB5_PROG_ETYPE_NOSUPP;
*ks_tuple_strs = NULL;
if (n_ks_tuple < 1)
return 0;
if ((ksnames = calloc(n_ks_tuple + 1, sizeof (*ksnames))) == NULL)
return (errno);
for (i = 0; i < n_ks_tuple; i++) {
char *ename, *sname;
if (krb5_enctype_to_string(context, ks_tuple[i].ks_enctype, &ename))
goto out;
if (krb5_salttype_to_string(context, ks_tuple[i].ks_enctype,
ks_tuple[i].ks_salttype, &sname)) {
free(ename);
goto out;
}
if (asprintf(&ksnames[i], "%s:%s", ename, sname) == -1) {
rc = errno;
free(ename);
free(sname);
goto out;
}
free(ename);
free(sname);
}
ksnames[i] = NULL;
*ks_tuple_strs = ksnames;
return 0;
out:
for (i = 0; i < n_ks_tuple; i++)
free(ksnames[i]);
free(ksnames);
return (rc);
}
/*
*
*/
static char **
glob_rules_keys(krb5_context context, krb5_const_principal principal)
{
const krb5_config_binding *list;
krb5_principal pattern;
krb5_error_code ret;
list = krb5_config_get_list(context, NULL, "kadmin",
"default_key_rules", NULL);
if (list == NULL)
return NULL;
while (list) {
if (list->type == krb5_config_string) {
ret = krb5_parse_name(context, list->name, &pattern);
if (ret == 0) {
ret = krb5_principal_match(context, principal, pattern);
krb5_free_principal(context, pattern);
if (ret) {
return krb5_config_get_strings(context, list,
list->name, NULL);
}
}
}
list = list->next;
}
return NULL;
}
/*
* NIST guidance in Section 5.1 of [SP800-132] requires that a portion
* of the salt of at least 128 bits shall be randomly generated.
*/
static krb5_error_code
add_random_to_salt(krb5_context context, krb5_salt *in, krb5_salt *out)
{
krb5_error_code ret;
char *p;
unsigned char random[16];
char *s;
int slen;
krb5_generate_random_block(random, sizeof(random));
slen = rk_base64_encode(random, sizeof(random), &s);
if (slen < 0)
return ENOMEM;
ret = krb5_data_alloc(&out->saltvalue, slen + in->saltvalue.length);
if (ret) {
free(s);
return ret;
}
p = out->saltvalue.data;
memcpy(p, s, slen);
memcpy(&p[slen], in->saltvalue.data, in->saltvalue.length);
out->salttype = in->salttype;
free(s);
return 0;
}
/*
* Generate the `key_set' from the [kadmin]default_keys statement. If
* `no_salt' is set, salt is not important (and will not be set) since
* it's random keys that is going to be created.
*/
krb5_error_code
hdb_generate_key_set(krb5_context context, krb5_principal principal,
krb5_key_salt_tuple *ks_tuple, int n_ks_tuple,
Key **ret_key_set, size_t *nkeyset, int no_salt)
{
char **ktypes = NULL;
char **kp;
krb5_error_code ret;
Key *k, *key_set;
size_t i, j;
char **ks_tuple_strs;
char **config_ktypes = NULL;
static const char *default_keytypes[] = {
"aes256-cts-hmac-sha1-96:pw-salt",
"des3-cbc-sha1:pw-salt",
"arcfour-hmac-md5:pw-salt",
NULL
};
if ((ret = ks_tuple2str(context, n_ks_tuple, ks_tuple, &ks_tuple_strs)))
return ret;
ktypes = ks_tuple_strs;
if (ktypes == NULL) {
ktypes = glob_rules_keys(context, principal);
}
if (ktypes == NULL) {
config_ktypes = krb5_config_get_strings(context, NULL, "kadmin",
"default_keys", NULL);
ktypes = config_ktypes;
}
if (ktypes == NULL)
ktypes = (char **)(intptr_t)default_keytypes;
*ret_key_set = key_set = NULL;
*nkeyset = 0;
for(kp = ktypes; kp && *kp; kp++) {
const char *p;
krb5_salt salt;
krb5_enctype *enctypes;
size_t num_enctypes;
p = *kp;
/* check alias */
if(strcmp(p, "v5") == 0)
p = "pw-salt";
else if(strcmp(p, "v4") == 0)
p = "des:pw-salt:";
else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
p = "des:afs3-salt";
else if (strcmp(p, "arcfour-hmac-md5") == 0)
p = "arcfour-hmac-md5:pw-salt";
memset(&salt, 0, sizeof(salt));
ret = parse_key_set(context, p,
&enctypes, &num_enctypes, &salt, principal);
if (ret) {
krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
ret = 0;
krb5_free_salt(context, salt);
continue;
}
for (i = 0; i < num_enctypes; i++) {
krb5_salt *saltp = no_salt ? NULL : &salt;
krb5_salt rsalt;
/* find duplicates */
for (j = 0; j < *nkeyset; j++) {
k = &key_set[j];
if (k->key.keytype == enctypes[i]) {
if (no_salt)
break;
if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
break;
if (k->salt->type == salt.salttype &&
k->salt->salt.length == salt.saltvalue.length &&
memcmp(k->salt->salt.data, salt.saltvalue.data,
salt.saltvalue.length) == 0)
break;
}
}
/* not a duplicate, lets add it */
if (j < *nkeyset)
continue;
memset(&rsalt, 0, sizeof(rsalt));
/* prepend salt with randomness if required */
if (!no_salt &&
_krb5_enctype_requires_random_salt(context, enctypes[i])) {
saltp = &rsalt;
ret = add_random_to_salt(context, &salt, &rsalt);
}
if (ret == 0)
ret = add_enctype_to_key_set(&key_set, nkeyset, enctypes[i],
saltp);
krb5_free_salt(context, rsalt);
if (ret) {
free(enctypes);
krb5_free_salt(context, salt);
goto out;
}
}
free(enctypes);
krb5_free_salt(context, salt);
}
*ret_key_set = key_set;
out:
if (config_ktypes != NULL)
krb5_config_free_strings(config_ktypes);
for(kp = ks_tuple_strs; kp && *kp; kp++)
free(*kp);
free(ks_tuple_strs);
if (ret) {
krb5_warn(context, ret,
"failed to parse the [kadmin]default_keys values");
for (i = 0; i < *nkeyset; i++)
free_Key(&key_set[i]);
free(key_set);
} else if (*nkeyset == 0) {
krb5_warnx(context,
"failed to parse any of the [kadmin]default_keys values");
ret = EINVAL; /* XXX */
}
return ret;
}
krb5_error_code
hdb_generate_key_set_password(krb5_context context,
krb5_principal principal,
const char *password,
krb5_key_salt_tuple *ks_tuple, int n_ks_tuple,
Key **keys, size_t *num_keys)
{
krb5_error_code ret;
size_t i;
ret = hdb_generate_key_set(context, principal, ks_tuple, n_ks_tuple,
keys, num_keys, 0);
if (ret)
return ret;
for (i = 0; i < (*num_keys); i++) {
krb5_salt salt;
Key *key = &(*keys)[i];
salt.salttype = key->salt->type;
salt.saltvalue.length = key->salt->salt.length;
salt.saltvalue.data = key->salt->salt.data;
ret = krb5_string_to_key_salt (context,
key->key.keytype,
password,
salt,
&key->key);
if(ret)
break;
}
if(ret) {
hdb_free_keys (context, *num_keys, *keys);
return ret;
}
return ret;
}