1/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
2 * project 1999.
3 */
4/* ====================================================================
5 * Copyright (c) 1999 The OpenSSL Project. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 *
19 * 3. All advertising materials mentioning features or use of this
20 * software must display the following acknowledgment:
21 * "This product includes software developed by the OpenSSL Project
22 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
23 *
24 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
25 * endorse or promote products derived from this software without
26 * prior written permission. For written permission, please contact
27 * licensing@OpenSSL.org.
28 *
29 * 5. Products derived from this software may not be called "OpenSSL"
30 * nor may "OpenSSL" appear in their names without prior written
31 * permission of the OpenSSL Project.
32 *
33 * 6. Redistributions of any form whatsoever must retain the following
34 * acknowledgment:
35 * "This product includes software developed by the OpenSSL Project
36 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
37 *
38 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
39 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
40 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
41 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
42 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
47 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
48 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
49 * OF THE POSSIBILITY OF SUCH DAMAGE.
50 * ====================================================================
51 *
52 * This product includes cryptographic software written by Eric Young
53 * (eay@cryptsoft.com). This product includes software written by Tim
54 * Hudson (tjh@cryptsoft.com). */
55
56#include <openssl/evp.h>
57
58#include <string.h>
59
60#include <openssl/hmac.h>
61
62#include "../internal.h"
63
64
65int PKCS5_PBKDF2_HMAC(const char *password, size_t password_len,
66 const uint8_t *salt, size_t salt_len, unsigned iterations,
67 const EVP_MD *digest, size_t key_len, uint8_t *out_key) {
68 // See RFC 8018, section 5.2.
69 int ret = 0;
70 size_t md_len = EVP_MD_size(digest);
71 uint32_t i = 1;
72 HMAC_CTX hctx;
73 HMAC_CTX_init(&hctx);
74
75 if (!HMAC_Init_ex(&hctx, password, password_len, digest, NULL)) {
76 goto err;
77 }
78
79 while (key_len > 0) {
80 size_t todo = md_len;
81 if (todo > key_len) {
82 todo = key_len;
83 }
84
85 uint8_t i_buf[4];
86 i_buf[0] = (uint8_t)((i >> 24) & 0xff);
87 i_buf[1] = (uint8_t)((i >> 16) & 0xff);
88 i_buf[2] = (uint8_t)((i >> 8) & 0xff);
89 i_buf[3] = (uint8_t)(i & 0xff);
90
91 // Compute U_1.
92 uint8_t digest_tmp[EVP_MAX_MD_SIZE];
93 if (!HMAC_Init_ex(&hctx, NULL, 0, NULL, NULL) ||
94 !HMAC_Update(&hctx, salt, salt_len) ||
95 !HMAC_Update(&hctx, i_buf, 4) ||
96 !HMAC_Final(&hctx, digest_tmp, NULL)) {
97 goto err;
98 }
99
100 OPENSSL_memcpy(out_key, digest_tmp, todo);
101 for (unsigned j = 1; j < iterations; j++) {
102 // Compute the remaining U_* values and XOR.
103 if (!HMAC_Init_ex(&hctx, NULL, 0, NULL, NULL) ||
104 !HMAC_Update(&hctx, digest_tmp, md_len) ||
105 !HMAC_Final(&hctx, digest_tmp, NULL)) {
106 goto err;
107 }
108 for (size_t k = 0; k < todo; k++) {
109 out_key[k] ^= digest_tmp[k];
110 }
111 }
112
113 key_len -= todo;
114 out_key += todo;
115 i++;
116 }
117
118 // RFC 8018 describes iterations (c) as being a "positive integer", so a
119 // value of 0 is an error.
120 //
121 // Unfortunately not all consumers of PKCS5_PBKDF2_HMAC() check their return
122 // value, expecting it to succeed and unconditionally using |out_key|. As a
123 // precaution for such callsites in external code, the old behavior of
124 // iterations < 1 being treated as iterations == 1 is preserved, but
125 // additionally an error result is returned.
126 //
127 // TODO(eroman): Figure out how to remove this compatibility hack, or change
128 // the default to something more sensible like 2048.
129 if (iterations == 0) {
130 goto err;
131 }
132
133 ret = 1;
134
135err:
136 HMAC_CTX_cleanup(&hctx);
137 return ret;
138}
139
140int PKCS5_PBKDF2_HMAC_SHA1(const char *password, size_t password_len,
141 const uint8_t *salt, size_t salt_len,
142 unsigned iterations, size_t key_len,
143 uint8_t *out_key) {
144 return PKCS5_PBKDF2_HMAC(password, password_len, salt, salt_len, iterations,
145 EVP_sha1(), key_len, out_key);
146}
147