2 * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
12 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
15 * The Single Step KDF algorithm is given by:
17 * Result(0) = empty bit string (i.e., the null string).
18 * For i = 1 to reps, do the following:
19 * Increment counter by 1.
20 * Result(i) = Result(i – 1) || H(counter || Z || FixedInfo).
21 * DKM = LeftmostBits(Result(reps), L))
24 * Z is a shared secret required to produce the derived key material.
25 * counter is a 4 byte buffer.
26 * FixedInfo is a bit string containing context specific data.
27 * DKM is the output derived key material.
28 * L is the required size of the DKM.
29 * reps = [L / H_outputBits]
30 * H(x) is the auxiliary function that can be either a hash, HMAC or KMAC.
31 * H_outputBits is the length of the output of the auxiliary function H(x).
33 * Currently there is not a comprehensive list of test vectors for this
34 * algorithm, especially for H(x) = HMAC and H(x) = KMAC.
35 * Test vectors for H(x) = Hash are indirectly used by CAVS KAS tests.
40 #include <openssl/hmac.h>
41 #include <openssl/evp.h>
42 #include <openssl/kdf.h>
43 #include "internal/cryptlib.h"
44 #include "internal/evp_int.h"
45 #include "kdf_local.h"
47 struct evp_kdf_impl_st
{
48 const EVP_MAC
*mac
; /* H(x) = HMAC_hash OR H(x) = KMAC */
49 const EVP_MD
*md
; /* H(x) = hash OR when H(x) = HMAC_hash */
50 unsigned char *secret
;
56 size_t out_len
; /* optional KMAC parameter */
59 #define SSKDF_MAX_INLEN (1<<30)
60 #define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
61 #define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)
63 /* KMAC uses a Customisation string of 'KDF' */
64 static const unsigned char kmac_custom_str
[] = { 0x4B, 0x44, 0x46 };
67 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
68 * Section 4. One-Step Key Derivation using H(x) = hash(x)
69 * Note: X9.63 also uses this code with the only difference being that the
70 * counter is appended to the secret 'z'.
72 * result[i] = Hash(counter || z || info) for One Step OR
73 * result[i] = Hash(z || counter || info) for X9.63.
75 static int SSKDF_hash_kdm(const EVP_MD
*kdf_md
,
76 const unsigned char *z
, size_t z_len
,
77 const unsigned char *info
, size_t info_len
,
78 unsigned int append_ctr
,
79 unsigned char *derived_key
, size_t derived_key_len
)
82 size_t counter
, out_len
, len
= derived_key_len
;
84 unsigned char mac
[EVP_MAX_MD_SIZE
];
85 unsigned char *out
= derived_key
;
86 EVP_MD_CTX
*ctx
= NULL
, *ctx_init
= NULL
;
88 if (z_len
> SSKDF_MAX_INLEN
|| info_len
> SSKDF_MAX_INLEN
89 || derived_key_len
> SSKDF_MAX_INLEN
90 || derived_key_len
== 0)
93 hlen
= EVP_MD_size(kdf_md
);
96 out_len
= (size_t)hlen
;
98 ctx
= EVP_MD_CTX_create();
99 ctx_init
= EVP_MD_CTX_create();
100 if (ctx
== NULL
|| ctx_init
== NULL
)
103 if (!EVP_DigestInit(ctx_init
, kdf_md
))
106 for (counter
= 1;; counter
++) {
107 c
[0] = (unsigned char)((counter
>> 24) & 0xff);
108 c
[1] = (unsigned char)((counter
>> 16) & 0xff);
109 c
[2] = (unsigned char)((counter
>> 8) & 0xff);
110 c
[3] = (unsigned char)(counter
& 0xff);
112 if (!(EVP_MD_CTX_copy_ex(ctx
, ctx_init
)
113 && (append_ctr
|| EVP_DigestUpdate(ctx
, c
, sizeof(c
)))
114 && EVP_DigestUpdate(ctx
, z
, z_len
)
115 && (!append_ctr
|| EVP_DigestUpdate(ctx
, c
, sizeof(c
)))
116 && EVP_DigestUpdate(ctx
, info
, info_len
)))
118 if (len
>= out_len
) {
119 if (!EVP_DigestFinal_ex(ctx
, out
, NULL
))
126 if (!EVP_DigestFinal_ex(ctx
, mac
, NULL
))
128 memcpy(out
, mac
, len
);
134 EVP_MD_CTX_destroy(ctx
);
135 EVP_MD_CTX_destroy(ctx_init
);
136 OPENSSL_cleanse(mac
, sizeof(mac
));
140 static int kmac_init(EVP_MAC_CTX
*ctx
, const unsigned char *custom
,
141 size_t custom_len
, size_t kmac_out_len
,
142 size_t derived_key_len
, unsigned char **out
)
144 /* Only KMAC has custom data - so return if not KMAC */
148 if (EVP_MAC_ctrl(ctx
, EVP_MAC_CTRL_SET_CUSTOM
, custom
, custom_len
) <= 0)
151 /* By default only do one iteration if kmac_out_len is not specified */
152 if (kmac_out_len
== 0)
153 kmac_out_len
= derived_key_len
;
154 /* otherwise check the size is valid */
155 else if (!(kmac_out_len
== derived_key_len
156 || kmac_out_len
== 20
157 || kmac_out_len
== 28
158 || kmac_out_len
== 32
159 || kmac_out_len
== 48
160 || kmac_out_len
== 64))
163 if (EVP_MAC_ctrl(ctx
, EVP_MAC_CTRL_SET_SIZE
, kmac_out_len
) <= 0)
167 * For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
168 * alloc a buffer for this case.
170 if (kmac_out_len
> EVP_MAX_MD_SIZE
) {
171 *out
= OPENSSL_zalloc(kmac_out_len
);
179 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
180 * Section 4. One-Step Key Derivation using MAC: i.e either
181 * H(x) = HMAC-hash(salt, x) OR
182 * H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
184 static int SSKDF_mac_kdm(const EVP_MAC
*kdf_mac
, const EVP_MD
*hmac_md
,
185 const unsigned char *kmac_custom
,
186 size_t kmac_custom_len
, size_t kmac_out_len
,
187 const unsigned char *salt
, size_t salt_len
,
188 const unsigned char *z
, size_t z_len
,
189 const unsigned char *info
, size_t info_len
,
190 unsigned char *derived_key
, size_t derived_key_len
)
193 size_t counter
, out_len
, len
;
195 unsigned char mac_buf
[EVP_MAX_MD_SIZE
];
196 unsigned char *out
= derived_key
;
197 EVP_MAC_CTX
*ctx
= NULL
, *ctx_init
= NULL
;
198 unsigned char *mac
= mac_buf
, *kmac_buffer
= NULL
;
200 if (z_len
> SSKDF_MAX_INLEN
|| info_len
> SSKDF_MAX_INLEN
201 || derived_key_len
> SSKDF_MAX_INLEN
202 || derived_key_len
== 0)
205 ctx
= EVP_MAC_CTX_new(kdf_mac
);
206 ctx_init
= EVP_MAC_CTX_new(kdf_mac
);
207 if (ctx
== NULL
|| ctx_init
== NULL
)
209 if (hmac_md
!= NULL
&&
210 EVP_MAC_ctrl(ctx_init
, EVP_MAC_CTRL_SET_MD
, hmac_md
) <= 0)
213 if (EVP_MAC_ctrl(ctx_init
, EVP_MAC_CTRL_SET_KEY
, salt
, salt_len
) <= 0)
216 if (!kmac_init(ctx_init
, kmac_custom
, kmac_custom_len
, kmac_out_len
,
217 derived_key_len
, &kmac_buffer
))
219 if (kmac_buffer
!= NULL
)
222 if (!EVP_MAC_init(ctx_init
))
225 out_len
= EVP_MAC_size(ctx_init
); /* output size */
228 len
= derived_key_len
;
230 for (counter
= 1;; counter
++) {
231 c
[0] = (unsigned char)((counter
>> 24) & 0xff);
232 c
[1] = (unsigned char)((counter
>> 16) & 0xff);
233 c
[2] = (unsigned char)((counter
>> 8) & 0xff);
234 c
[3] = (unsigned char)(counter
& 0xff);
236 if (!(EVP_MAC_CTX_copy(ctx
, ctx_init
)
237 && EVP_MAC_update(ctx
, c
, sizeof(c
))
238 && EVP_MAC_update(ctx
, z
, z_len
)
239 && EVP_MAC_update(ctx
, info
, info_len
)))
241 if (len
>= out_len
) {
242 if (!EVP_MAC_final(ctx
, out
, NULL
))
249 if (!EVP_MAC_final(ctx
, mac
, NULL
))
251 memcpy(out
, mac
, len
);
257 if (kmac_buffer
!= NULL
)
258 OPENSSL_clear_free(kmac_buffer
, kmac_out_len
);
260 OPENSSL_cleanse(mac_buf
, sizeof(mac_buf
));
262 EVP_MAC_CTX_free(ctx
);
263 EVP_MAC_CTX_free(ctx_init
);
267 static EVP_KDF_IMPL
*sskdf_new(void)
271 if ((impl
= OPENSSL_zalloc(sizeof(*impl
))) == NULL
)
272 KDFerr(KDF_F_SSKDF_NEW
, ERR_R_MALLOC_FAILURE
);
276 static void sskdf_reset(EVP_KDF_IMPL
*impl
)
278 OPENSSL_clear_free(impl
->secret
, impl
->secret_len
);
279 OPENSSL_clear_free(impl
->info
, impl
->info_len
);
280 OPENSSL_clear_free(impl
->salt
, impl
->salt_len
);
281 memset(impl
, 0, sizeof(*impl
));
284 static void sskdf_free(EVP_KDF_IMPL
*impl
)
290 static int sskdf_set_buffer(va_list args
, unsigned char **out
, size_t *out_len
)
292 const unsigned char *p
;
295 p
= va_arg(args
, const unsigned char *);
296 len
= va_arg(args
, size_t);
297 if (len
== 0 || p
== NULL
)
301 *out
= OPENSSL_memdup(p
, len
);
309 static int sskdf_ctrl(EVP_KDF_IMPL
*impl
, int cmd
, va_list args
)
315 case EVP_KDF_CTRL_SET_KEY
:
316 return sskdf_set_buffer(args
, &impl
->secret
, &impl
->secret_len
);
318 case EVP_KDF_CTRL_SET_SSKDF_INFO
:
319 return sskdf_set_buffer(args
, &impl
->info
, &impl
->info_len
);
321 case EVP_KDF_CTRL_SET_MD
:
322 md
= va_arg(args
, const EVP_MD
*);
329 case EVP_KDF_CTRL_SET_MAC
:
330 mac
= va_arg(args
, const EVP_MAC
*);
337 case EVP_KDF_CTRL_SET_SALT
:
338 return sskdf_set_buffer(args
, &impl
->salt
, &impl
->salt_len
);
340 case EVP_KDF_CTRL_SET_MAC_SIZE
:
341 impl
->out_len
= va_arg(args
, size_t);
349 /* Pass a mac to a ctrl */
350 static int sskdf_mac2ctrl(EVP_KDF_IMPL
*impl
,
351 int (*ctrl
)(EVP_KDF_IMPL
*impl
, int cmd
, va_list args
),
352 int cmd
, const char *mac_name
)
356 if (mac_name
== NULL
|| (mac
= EVP_get_macbyname(mac_name
)) == NULL
) {
357 KDFerr(KDF_F_SSKDF_MAC2CTRL
, KDF_R_INVALID_MAC_TYPE
);
360 return call_ctrl(ctrl
, impl
, cmd
, mac
);
363 static int sskdf_ctrl_str(EVP_KDF_IMPL
*impl
, const char *type
,
366 if (strcmp(type
, "secret") == 0 || strcmp(type
, "key") == 0)
367 return kdf_str2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_KEY
,
370 if (strcmp(type
, "hexsecret") == 0 || strcmp(type
, "hexkey") == 0)
371 return kdf_hex2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_KEY
,
374 if (strcmp(type
, "info") == 0)
375 return kdf_str2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_SSKDF_INFO
,
378 if (strcmp(type
, "hexinfo") == 0)
379 return kdf_hex2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_SSKDF_INFO
,
382 if (strcmp(type
, "digest") == 0)
383 return kdf_md2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_MD
, value
);
385 if (strcmp(type
, "mac") == 0)
386 return sskdf_mac2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_MAC
, value
);
388 if (strcmp(type
, "salt") == 0)
389 return kdf_str2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_SALT
, value
);
391 if (strcmp(type
, "hexsalt") == 0)
392 return kdf_hex2ctrl(impl
, sskdf_ctrl
, EVP_KDF_CTRL_SET_SALT
, value
);
395 if (strcmp(type
, "maclen") == 0) {
396 int val
= atoi(value
);
398 KDFerr(KDF_F_SSKDF_CTRL_STR
, KDF_R_VALUE_ERROR
);
401 return call_ctrl(sskdf_ctrl
, impl
, EVP_KDF_CTRL_SET_MAC_SIZE
,
407 static size_t sskdf_size(EVP_KDF_IMPL
*impl
)
411 if (impl
->md
== NULL
) {
412 KDFerr(KDF_F_SSKDF_SIZE
, KDF_R_MISSING_MESSAGE_DIGEST
);
415 len
= EVP_MD_size(impl
->md
);
416 return (len
<= 0) ? 0 : (size_t)len
;
419 static int sskdf_derive(EVP_KDF_IMPL
*impl
, unsigned char *key
, size_t keylen
)
421 if (impl
->secret
== NULL
) {
422 KDFerr(KDF_F_SSKDF_DERIVE
, KDF_R_MISSING_SECRET
);
426 if (impl
->mac
!= NULL
) {
427 /* H(x) = KMAC or H(x) = HMAC */
429 const unsigned char *custom
= NULL
;
430 size_t custom_len
= 0;
432 int default_salt_len
;
434 nid
= EVP_MAC_nid(impl
->mac
);
435 if (nid
== EVP_MAC_HMAC
) {
436 /* H(x) = HMAC(x, salt, hash) */
437 if (impl
->md
== NULL
) {
438 KDFerr(KDF_F_SSKDF_DERIVE
, KDF_R_MISSING_MESSAGE_DIGEST
);
441 default_salt_len
= EVP_MD_block_size(impl
->md
);
442 if (default_salt_len
<= 0)
444 } else if (nid
== EVP_MAC_KMAC128
|| nid
== EVP_MAC_KMAC256
) {
445 /* H(x) = KMACzzz(x, salt, custom) */
446 custom
= kmac_custom_str
;
447 custom_len
= sizeof(kmac_custom_str
);
448 if (nid
== EVP_MAC_KMAC128
)
449 default_salt_len
= SSKDF_KMAC128_DEFAULT_SALT_SIZE
;
451 default_salt_len
= SSKDF_KMAC256_DEFAULT_SALT_SIZE
;
453 KDFerr(KDF_F_SSKDF_DERIVE
, KDF_R_UNSUPPORTED_MAC_TYPE
);
456 /* If no salt is set then use a default_salt of zeros */
457 if (impl
->salt
== NULL
|| impl
->salt_len
<= 0) {
458 impl
->salt
= OPENSSL_zalloc(default_salt_len
);
459 if (impl
->salt
== NULL
) {
460 KDFerr(KDF_F_SSKDF_DERIVE
, ERR_R_MALLOC_FAILURE
);
463 impl
->salt_len
= default_salt_len
;
465 ret
= SSKDF_mac_kdm(impl
->mac
, impl
->md
,
466 custom
, custom_len
, impl
->out_len
,
467 impl
->salt
, impl
->salt_len
,
468 impl
->secret
, impl
->secret_len
,
469 impl
->info
, impl
->info_len
, key
, keylen
);
473 if (impl
->md
== NULL
) {
474 KDFerr(KDF_F_SSKDF_DERIVE
, KDF_R_MISSING_MESSAGE_DIGEST
);
477 return SSKDF_hash_kdm(impl
->md
, impl
->secret
, impl
->secret_len
,
478 impl
->info
, impl
->info_len
, 0, key
, keylen
);
482 static int x963kdf_derive(EVP_KDF_IMPL
*impl
, unsigned char *key
, size_t keylen
)
484 if (impl
->secret
== NULL
) {
485 KDFerr(KDF_F_X963KDF_DERIVE
, KDF_R_MISSING_SECRET
);
489 if (impl
->mac
!= NULL
) {
490 KDFerr(KDF_F_X963KDF_DERIVE
, KDF_R_NOT_SUPPORTED
);
494 if (impl
->md
== NULL
) {
495 KDFerr(KDF_F_X963KDF_DERIVE
, KDF_R_MISSING_MESSAGE_DIGEST
);
498 return SSKDF_hash_kdm(impl
->md
, impl
->secret
, impl
->secret_len
,
499 impl
->info
, impl
->info_len
, 1, key
, keylen
);
503 const EVP_KDF ss_kdf_meth
= {
514 const EVP_KDF x963_kdf_meth
= {