2 * Copyright 2019-2022 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 <openssl/core_names.h>
44 #include <openssl/params.h>
45 #include <openssl/proverr.h>
46 #include "internal/cryptlib.h"
47 #include "internal/numbers.h"
48 #include "crypto/evp.h"
49 #include "prov/provider_ctx.h"
50 #include "prov/providercommon.h"
51 #include "prov/implementations.h"
52 #include "prov/provider_util.h"
56 EVP_MAC_CTX *macctx; /* H(x) = HMAC_hash OR H(x) = KMAC */
57 PROV_DIGEST digest; /* H(x) = hash(x) */
58 unsigned char *secret;
64 size_t out_len; /* optional KMAC parameter */
67 #define SSKDF_MAX_INLEN (1<<30)
68 #define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
69 #define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)
71 /* KMAC uses a Customisation string of 'KDF' */
72 static const unsigned char kmac_custom_str[] = { 0x4B, 0x44, 0x46 };
74 static OSSL_FUNC_kdf_newctx_fn sskdf_new;
75 static OSSL_FUNC_kdf_dupctx_fn sskdf_dup;
76 static OSSL_FUNC_kdf_freectx_fn sskdf_free;
77 static OSSL_FUNC_kdf_reset_fn sskdf_reset;
78 static OSSL_FUNC_kdf_derive_fn sskdf_derive;
79 static OSSL_FUNC_kdf_derive_fn x963kdf_derive;
80 static OSSL_FUNC_kdf_settable_ctx_params_fn sskdf_settable_ctx_params;
81 static OSSL_FUNC_kdf_set_ctx_params_fn sskdf_set_ctx_params;
82 static OSSL_FUNC_kdf_gettable_ctx_params_fn sskdf_gettable_ctx_params;
83 static OSSL_FUNC_kdf_get_ctx_params_fn sskdf_get_ctx_params;
86 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
87 * Section 4. One-Step Key Derivation using H(x) = hash(x)
88 * Note: X9.63 also uses this code with the only difference being that the
89 * counter is appended to the secret 'z'.
91 * result[i] = Hash(counter || z || info) for One Step OR
92 * result[i] = Hash(z || counter || info) for X9.63.
94 static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
95 const unsigned char *z, size_t z_len,
96 const unsigned char *info, size_t info_len,
97 unsigned int append_ctr,
98 unsigned char *derived_key, size_t derived_key_len)
101 size_t counter, out_len, len = derived_key_len;
103 unsigned char mac[EVP_MAX_MD_SIZE];
104 unsigned char *out = derived_key;
105 EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
107 if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
108 || derived_key_len > SSKDF_MAX_INLEN
109 || derived_key_len == 0)
112 hlen = EVP_MD_get_size(kdf_md);
115 out_len = (size_t)hlen;
117 ctx = EVP_MD_CTX_create();
118 ctx_init = EVP_MD_CTX_create();
119 if (ctx == NULL || ctx_init == NULL)
122 if (!EVP_DigestInit(ctx_init, kdf_md))
125 for (counter = 1;; counter++) {
126 c[0] = (unsigned char)((counter >> 24) & 0xff);
127 c[1] = (unsigned char)((counter >> 16) & 0xff);
128 c[2] = (unsigned char)((counter >> 8) & 0xff);
129 c[3] = (unsigned char)(counter & 0xff);
131 if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
132 && (append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
133 && EVP_DigestUpdate(ctx, z, z_len)
134 && (!append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
135 && EVP_DigestUpdate(ctx, info, info_len)))
137 if (len >= out_len) {
138 if (!EVP_DigestFinal_ex(ctx, out, NULL))
145 if (!EVP_DigestFinal_ex(ctx, mac, NULL))
147 memcpy(out, mac, len);
153 EVP_MD_CTX_destroy(ctx);
154 EVP_MD_CTX_destroy(ctx_init);
155 OPENSSL_cleanse(mac, sizeof(mac));
159 static int kmac_init(EVP_MAC_CTX *ctx, const unsigned char *custom,
160 size_t custom_len, size_t kmac_out_len,
161 size_t derived_key_len, unsigned char **out)
163 OSSL_PARAM params[2];
165 /* Only KMAC has custom data - so return if not KMAC */
169 params[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
170 (void *)custom, custom_len);
171 params[1] = OSSL_PARAM_construct_end();
173 if (!EVP_MAC_CTX_set_params(ctx, params))
176 /* By default only do one iteration if kmac_out_len is not specified */
177 if (kmac_out_len == 0)
178 kmac_out_len = derived_key_len;
179 /* otherwise check the size is valid */
180 else if (!(kmac_out_len == derived_key_len
181 || kmac_out_len == 20
182 || kmac_out_len == 28
183 || kmac_out_len == 32
184 || kmac_out_len == 48
185 || kmac_out_len == 64))
188 params[0] = OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE,
191 if (EVP_MAC_CTX_set_params(ctx, params) <= 0)
195 * For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
196 * alloc a buffer for this case.
198 if (kmac_out_len > EVP_MAX_MD_SIZE) {
199 *out = OPENSSL_zalloc(kmac_out_len);
207 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
208 * Section 4. One-Step Key Derivation using MAC: i.e either
209 * H(x) = HMAC-hash(salt, x) OR
210 * H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
212 static int SSKDF_mac_kdm(EVP_MAC_CTX *ctx_init,
213 const unsigned char *kmac_custom,
214 size_t kmac_custom_len, size_t kmac_out_len,
215 const unsigned char *salt, size_t salt_len,
216 const unsigned char *z, size_t z_len,
217 const unsigned char *info, size_t info_len,
218 unsigned char *derived_key, size_t derived_key_len)
221 size_t counter, out_len, len;
223 unsigned char mac_buf[EVP_MAX_MD_SIZE];
224 unsigned char *out = derived_key;
225 EVP_MAC_CTX *ctx = NULL;
226 unsigned char *mac = mac_buf, *kmac_buffer = NULL;
228 if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
229 || derived_key_len > SSKDF_MAX_INLEN
230 || derived_key_len == 0)
233 if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
234 derived_key_len, &kmac_buffer))
236 if (kmac_buffer != NULL)
239 if (!EVP_MAC_init(ctx_init, salt, salt_len, NULL))
242 out_len = EVP_MAC_CTX_get_mac_size(ctx_init); /* output size */
243 if (out_len <= 0 || (mac == mac_buf && out_len > sizeof(mac_buf)))
245 len = derived_key_len;
247 for (counter = 1;; counter++) {
248 c[0] = (unsigned char)((counter >> 24) & 0xff);
249 c[1] = (unsigned char)((counter >> 16) & 0xff);
250 c[2] = (unsigned char)((counter >> 8) & 0xff);
251 c[3] = (unsigned char)(counter & 0xff);
253 ctx = EVP_MAC_CTX_dup(ctx_init);
255 && EVP_MAC_update(ctx, c, sizeof(c))
256 && EVP_MAC_update(ctx, z, z_len)
257 && EVP_MAC_update(ctx, info, info_len)))
259 if (len >= out_len) {
260 if (!EVP_MAC_final(ctx, out, NULL, len))
267 if (!EVP_MAC_final(ctx, mac, NULL, out_len))
269 memcpy(out, mac, len);
272 EVP_MAC_CTX_free(ctx);
277 if (kmac_buffer != NULL)
278 OPENSSL_clear_free(kmac_buffer, kmac_out_len);
280 OPENSSL_cleanse(mac_buf, sizeof(mac_buf));
282 EVP_MAC_CTX_free(ctx);
286 static void *sskdf_new(void *provctx)
290 if (!ossl_prov_is_running())
293 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
294 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
295 ctx->provctx = provctx;
299 static void sskdf_reset(void *vctx)
301 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
302 void *provctx = ctx->provctx;
304 EVP_MAC_CTX_free(ctx->macctx);
305 ossl_prov_digest_reset(&ctx->digest);
306 OPENSSL_clear_free(ctx->secret, ctx->secret_len);
307 OPENSSL_clear_free(ctx->info, ctx->info_len);
308 OPENSSL_clear_free(ctx->salt, ctx->salt_len);
309 memset(ctx, 0, sizeof(*ctx));
310 ctx->provctx = provctx;
313 static void sskdf_free(void *vctx)
315 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
323 static void *sskdf_dup(void *vctx)
325 const KDF_SSKDF *src = (const KDF_SSKDF *)vctx;
328 dest = sskdf_new(src->provctx);
330 if (src->macctx != NULL) {
331 dest->macctx = EVP_MAC_CTX_dup(src->macctx);
332 if (dest->macctx == NULL)
335 if (!ossl_prov_memdup(src->info, src->info_len,
336 &dest->info, &dest->info_len)
337 || !ossl_prov_memdup(src->salt, src->salt_len,
338 &dest->salt , &dest->salt_len)
339 || !ossl_prov_memdup(src->secret, src->secret_len,
340 &dest->secret, &dest->secret_len)
341 || !ossl_prov_digest_copy(&dest->digest, &src->digest))
343 dest->out_len = src->out_len;
352 static int sskdf_set_buffer(unsigned char **out, size_t *out_len,
355 if (p->data == NULL || p->data_size == 0)
359 return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
362 static size_t sskdf_size(KDF_SSKDF *ctx)
365 const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
368 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
371 len = EVP_MD_get_size(md);
372 return (len <= 0) ? 0 : (size_t)len;
375 static int sskdf_derive(void *vctx, unsigned char *key, size_t keylen,
376 const OSSL_PARAM params[])
378 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
381 if (!ossl_prov_is_running() || !sskdf_set_ctx_params(ctx, params))
383 if (ctx->secret == NULL) {
384 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
387 md = ossl_prov_digest_md(&ctx->digest);
389 if (ctx->macctx != NULL) {
390 /* H(x) = KMAC or H(x) = HMAC */
392 const unsigned char *custom = NULL;
393 size_t custom_len = 0;
394 int default_salt_len;
395 EVP_MAC *mac = EVP_MAC_CTX_get0_mac(ctx->macctx);
397 if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_HMAC)) {
398 /* H(x) = HMAC(x, salt, hash) */
400 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
403 default_salt_len = EVP_MD_get_size(md);
404 if (default_salt_len <= 0)
406 } else if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_KMAC128)
407 || EVP_MAC_is_a(mac, OSSL_MAC_NAME_KMAC256)) {
408 /* H(x) = KMACzzz(x, salt, custom) */
409 custom = kmac_custom_str;
410 custom_len = sizeof(kmac_custom_str);
411 if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_KMAC128))
412 default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
414 default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
416 ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_MAC_TYPE);
419 /* If no salt is set then use a default_salt of zeros */
420 if (ctx->salt == NULL || ctx->salt_len <= 0) {
421 ctx->salt = OPENSSL_zalloc(default_salt_len);
422 if (ctx->salt == NULL) {
423 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
426 ctx->salt_len = default_salt_len;
428 ret = SSKDF_mac_kdm(ctx->macctx,
429 custom, custom_len, ctx->out_len,
430 ctx->salt, ctx->salt_len,
431 ctx->secret, ctx->secret_len,
432 ctx->info, ctx->info_len, key, keylen);
437 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
440 return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
441 ctx->info, ctx->info_len, 0, key, keylen);
445 static int x963kdf_derive(void *vctx, unsigned char *key, size_t keylen,
446 const OSSL_PARAM params[])
448 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
451 if (!ossl_prov_is_running() || !sskdf_set_ctx_params(ctx, params))
454 if (ctx->secret == NULL) {
455 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
459 if (ctx->macctx != NULL) {
460 ERR_raise(ERR_LIB_PROV, PROV_R_NOT_SUPPORTED);
465 md = ossl_prov_digest_md(&ctx->digest);
467 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
471 return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
472 ctx->info, ctx->info_len, 1, key, keylen);
475 static int sskdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
478 KDF_SSKDF *ctx = vctx;
479 OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
485 if (!ossl_prov_digest_load_from_params(&ctx->digest, params, libctx))
488 if (!ossl_prov_macctx_load_from_params(&ctx->macctx, params,
489 NULL, NULL, NULL, libctx))
492 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
493 || (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
494 if (!sskdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
497 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO)) != NULL)
498 if (!sskdf_set_buffer(&ctx->info, &ctx->info_len, p))
501 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
502 if (!sskdf_set_buffer(&ctx->salt, &ctx->salt_len, p))
505 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MAC_SIZE))
507 if (!OSSL_PARAM_get_size_t(p, &sz) || sz == 0)
514 static const OSSL_PARAM *sskdf_settable_ctx_params(ossl_unused void *ctx,
515 ossl_unused void *provctx)
517 static const OSSL_PARAM known_settable_ctx_params[] = {
518 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
519 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
520 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
521 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
522 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
523 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
524 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
525 OSSL_PARAM_size_t(OSSL_KDF_PARAM_MAC_SIZE, NULL),
528 return known_settable_ctx_params;
531 static int sskdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
533 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
536 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
537 return OSSL_PARAM_set_size_t(p, sskdf_size(ctx));
541 static const OSSL_PARAM *sskdf_gettable_ctx_params(ossl_unused void *ctx,
542 ossl_unused void *provctx)
544 static const OSSL_PARAM known_gettable_ctx_params[] = {
545 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
548 return known_gettable_ctx_params;
551 const OSSL_DISPATCH ossl_kdf_sskdf_functions[] = {
552 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
553 { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))sskdf_dup },
554 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
555 { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
556 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))sskdf_derive },
557 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
558 (void(*)(void))sskdf_settable_ctx_params },
559 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
560 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
561 (void(*)(void))sskdf_gettable_ctx_params },
562 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
566 const OSSL_DISPATCH ossl_kdf_x963_kdf_functions[] = {
567 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
568 { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))sskdf_dup },
569 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
570 { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
571 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x963kdf_derive },
572 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
573 (void(*)(void))sskdf_settable_ctx_params },
574 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
575 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
576 (void(*)(void))sskdf_gettable_ctx_params },
577 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },