1/*	$NetBSD: salt-aes-sha2.c,v 1.3 2023/06/19 21:41:44 christos Exp $	*/
2
3/*
4 * Copyright (c) 1997 - 2008 Kungliga Tekniska H��gskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "krb5_locl.h"
37
38int _krb5_AES_SHA2_string_to_default_iterator = 32768;
39
40static krb5_error_code
41AES_SHA2_string_to_key(krb5_context context,
42		       krb5_enctype enctype,
43		       krb5_data password,
44		       krb5_salt salt,
45		       krb5_data opaque,
46		       krb5_keyblock *key)
47{
48    krb5_error_code ret;
49    uint32_t iter;
50    struct _krb5_encryption_type *et = NULL;
51    struct _krb5_key_data kd;
52    krb5_data saltp;
53    size_t enctypesz;
54    const EVP_MD *md = NULL;
55
56    krb5_data_zero(&saltp);
57    kd.key = NULL;
58    kd.schedule = NULL;
59
60    if (opaque.length == 0) {
61	iter = _krb5_AES_SHA2_string_to_default_iterator;
62    } else if (opaque.length == 4) {
63	unsigned long v;
64	_krb5_get_int(opaque.data, &v, 4);
65	iter = ((uint32_t)v);
66    } else {
67	ret = KRB5_PROG_KEYTYPE_NOSUPP; /* XXX */
68	goto cleanup;
69    }
70
71    et = _krb5_find_enctype(enctype);
72    if (et == NULL) {
73	ret = KRB5_PROG_KEYTYPE_NOSUPP;
74	goto cleanup;
75    }
76
77    kd.schedule = NULL;
78    ALLOC(kd.key, 1);
79    if (kd.key == NULL) {
80	ret = krb5_enomem(context);
81	goto cleanup;
82    }
83    kd.key->keytype = enctype;
84    ret = krb5_data_alloc(&kd.key->keyvalue, et->keytype->size);
85    if (ret) {
86	ret = krb5_enomem(context);
87	goto cleanup;
88    }
89
90    enctypesz = strlen(et->name) + 1;
91    ret = krb5_data_alloc(&saltp, enctypesz + salt.saltvalue.length);
92    if (ret) {
93	ret = krb5_enomem(context);
94	goto cleanup;
95    }
96    memcpy(saltp.data, et->name, enctypesz);
97    if (salt.saltvalue.length)
98        memcpy((unsigned char *)saltp.data + enctypesz,
99               salt.saltvalue.data, salt.saltvalue.length);
100
101    ret = _krb5_aes_sha2_md_for_enctype(context, enctype, &md);
102    if (ret)
103	goto cleanup;
104
105    ret = PKCS5_PBKDF2_HMAC(password.data, password.length,
106			    saltp.data, saltp.length,
107			    iter, md,
108			    et->keytype->size, kd.key->keyvalue.data);
109    if (ret != 1) {
110	krb5_set_error_message(context, KRB5_PROG_KEYTYPE_NOSUPP,
111			       "Error calculating s2k");
112	ret = KRB5_PROG_KEYTYPE_NOSUPP;
113	goto cleanup;
114    }
115
116    ret = _krb5_derive_key(context, et, &kd, "kerberos", strlen("kerberos"));
117    if (ret)
118	goto cleanup;
119
120    ret = krb5_copy_keyblock_contents(context, kd.key, key);
121    if (ret)
122	goto cleanup;
123
124cleanup:
125    krb5_data_free(&saltp);
126    _krb5_free_key_data(context, &kd, et);
127
128    return ret;
129}
130
131struct salt_type _krb5_AES_SHA2_salt[] = {
132    {
133	KRB5_PW_SALT,
134	"pw-salt",
135	AES_SHA2_string_to_key
136    },
137    { 0, NULL, NULL }
138};
139