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"
53 #include "internal/params.h"
57 EVP_MAC_CTX *macctx; /* H(x) = HMAC_hash OR H(x) = KMAC */
58 PROV_DIGEST digest; /* H(x) = hash(x) */
59 unsigned char *secret;
65 size_t out_len; /* optional KMAC parameter */
69 #define SSKDF_MAX_INLEN (1<<30)
70 #define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
71 #define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)
73 /* KMAC uses a Customisation string of 'KDF' */
74 static const unsigned char kmac_custom_str[] = { 0x4B, 0x44, 0x46 };
76 static OSSL_FUNC_kdf_newctx_fn sskdf_new;
77 static OSSL_FUNC_kdf_dupctx_fn sskdf_dup;
78 static OSSL_FUNC_kdf_freectx_fn sskdf_free;
79 static OSSL_FUNC_kdf_reset_fn sskdf_reset;
80 static OSSL_FUNC_kdf_derive_fn sskdf_derive;
81 static OSSL_FUNC_kdf_derive_fn x963kdf_derive;
82 static OSSL_FUNC_kdf_settable_ctx_params_fn sskdf_settable_ctx_params;
83 static OSSL_FUNC_kdf_set_ctx_params_fn sskdf_set_ctx_params;
84 static OSSL_FUNC_kdf_gettable_ctx_params_fn sskdf_gettable_ctx_params;
85 static OSSL_FUNC_kdf_get_ctx_params_fn sskdf_get_ctx_params;
88 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
89 * Section 4. One-Step Key Derivation using H(x) = hash(x)
90 * Note: X9.63 also uses this code with the only difference being that the
91 * counter is appended to the secret 'z'.
93 * result[i] = Hash(counter || z || info) for One Step OR
94 * result[i] = Hash(z || counter || info) for X9.63.
96 static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
97 const unsigned char *z, size_t z_len,
98 const unsigned char *info, size_t info_len,
99 unsigned int append_ctr,
100 unsigned char *derived_key, size_t derived_key_len)
103 size_t counter, out_len, len = derived_key_len;
105 unsigned char mac[EVP_MAX_MD_SIZE];
106 unsigned char *out = derived_key;
107 EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
109 if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
110 || derived_key_len > SSKDF_MAX_INLEN
111 || derived_key_len == 0)
114 hlen = EVP_MD_get_size(kdf_md);
117 out_len = (size_t)hlen;
119 ctx = EVP_MD_CTX_create();
120 ctx_init = EVP_MD_CTX_create();
121 if (ctx == NULL || ctx_init == NULL)
124 if (!EVP_DigestInit(ctx_init, kdf_md))
127 for (counter = 1;; counter++) {
128 c[0] = (unsigned char)((counter >> 24) & 0xff);
129 c[1] = (unsigned char)((counter >> 16) & 0xff);
130 c[2] = (unsigned char)((counter >> 8) & 0xff);
131 c[3] = (unsigned char)(counter & 0xff);
133 if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
134 && (append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
135 && EVP_DigestUpdate(ctx, z, z_len)
136 && (!append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
137 && EVP_DigestUpdate(ctx, info, info_len)))
139 if (len >= out_len) {
140 if (!EVP_DigestFinal_ex(ctx, out, NULL))
147 if (!EVP_DigestFinal_ex(ctx, mac, NULL))
149 memcpy(out, mac, len);
155 EVP_MD_CTX_destroy(ctx);
156 EVP_MD_CTX_destroy(ctx_init);
157 OPENSSL_cleanse(mac, sizeof(mac));
161 static int kmac_init(EVP_MAC_CTX *ctx, const unsigned char *custom,
162 size_t custom_len, size_t kmac_out_len,
163 size_t derived_key_len, unsigned char **out)
165 OSSL_PARAM params[2];
167 /* Only KMAC has custom data - so return if not KMAC */
171 params[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
172 (void *)custom, custom_len);
173 params[1] = OSSL_PARAM_construct_end();
175 if (!EVP_MAC_CTX_set_params(ctx, params))
178 /* By default only do one iteration if kmac_out_len is not specified */
179 if (kmac_out_len == 0)
180 kmac_out_len = derived_key_len;
181 /* otherwise check the size is valid */
182 else if (!(kmac_out_len == derived_key_len
183 || kmac_out_len == 20
184 || kmac_out_len == 28
185 || kmac_out_len == 32
186 || kmac_out_len == 48
187 || kmac_out_len == 64))
190 params[0] = OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE,
193 if (EVP_MAC_CTX_set_params(ctx, params) <= 0)
197 * For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
198 * alloc a buffer for this case.
200 if (kmac_out_len > EVP_MAX_MD_SIZE) {
201 *out = OPENSSL_zalloc(kmac_out_len);
209 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
210 * Section 4. One-Step Key Derivation using MAC: i.e either
211 * H(x) = HMAC-hash(salt, x) OR
212 * H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
214 static int SSKDF_mac_kdm(EVP_MAC_CTX *ctx_init,
215 const unsigned char *kmac_custom,
216 size_t kmac_custom_len, size_t kmac_out_len,
217 const unsigned char *salt, size_t salt_len,
218 const unsigned char *z, size_t z_len,
219 const unsigned char *info, size_t info_len,
220 unsigned char *derived_key, size_t derived_key_len)
223 size_t counter, out_len, len;
225 unsigned char mac_buf[EVP_MAX_MD_SIZE];
226 unsigned char *out = derived_key;
227 EVP_MAC_CTX *ctx = NULL;
228 unsigned char *mac = mac_buf, *kmac_buffer = NULL;
230 if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
231 || derived_key_len > SSKDF_MAX_INLEN
232 || derived_key_len == 0)
235 if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
236 derived_key_len, &kmac_buffer))
238 if (kmac_buffer != NULL)
241 if (!EVP_MAC_init(ctx_init, salt, salt_len, NULL))
244 out_len = EVP_MAC_CTX_get_mac_size(ctx_init); /* output size */
245 if (out_len <= 0 || (mac == mac_buf && out_len > sizeof(mac_buf)))
247 len = derived_key_len;
249 for (counter = 1;; counter++) {
250 c[0] = (unsigned char)((counter >> 24) & 0xff);
251 c[1] = (unsigned char)((counter >> 16) & 0xff);
252 c[2] = (unsigned char)((counter >> 8) & 0xff);
253 c[3] = (unsigned char)(counter & 0xff);
255 ctx = EVP_MAC_CTX_dup(ctx_init);
257 && EVP_MAC_update(ctx, c, sizeof(c))
258 && EVP_MAC_update(ctx, z, z_len)
259 && EVP_MAC_update(ctx, info, info_len)))
261 if (len >= out_len) {
262 if (!EVP_MAC_final(ctx, out, NULL, len))
269 if (!EVP_MAC_final(ctx, mac, NULL, out_len))
271 memcpy(out, mac, len);
274 EVP_MAC_CTX_free(ctx);
279 if (kmac_buffer != NULL)
280 OPENSSL_clear_free(kmac_buffer, kmac_out_len);
282 OPENSSL_cleanse(mac_buf, sizeof(mac_buf));
284 EVP_MAC_CTX_free(ctx);
288 static void *sskdf_new(void *provctx)
292 if (!ossl_prov_is_running())
295 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL)
296 ctx->provctx = provctx;
300 static void sskdf_reset(void *vctx)
302 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
303 void *provctx = ctx->provctx;
305 EVP_MAC_CTX_free(ctx->macctx);
306 ossl_prov_digest_reset(&ctx->digest);
307 OPENSSL_clear_free(ctx->secret, ctx->secret_len);
308 OPENSSL_clear_free(ctx->info, ctx->info_len);
309 OPENSSL_clear_free(ctx->salt, ctx->salt_len);
310 memset(ctx, 0, sizeof(*ctx));
311 ctx->provctx = provctx;
314 static void sskdf_free(void *vctx)
316 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
324 static void *sskdf_dup(void *vctx)
326 const KDF_SSKDF *src = (const KDF_SSKDF *)vctx;
329 dest = sskdf_new(src->provctx);
331 if (src->macctx != NULL) {
332 dest->macctx = EVP_MAC_CTX_dup(src->macctx);
333 if (dest->macctx == NULL)
336 if (!ossl_prov_memdup(src->info, src->info_len,
337 &dest->info, &dest->info_len)
338 || !ossl_prov_memdup(src->salt, src->salt_len,
339 &dest->salt , &dest->salt_len)
340 || !ossl_prov_memdup(src->secret, src->secret_len,
341 &dest->secret, &dest->secret_len)
342 || !ossl_prov_digest_copy(&dest->digest, &src->digest))
344 dest->out_len = src->out_len;
345 dest->is_kmac = src->is_kmac;
354 static size_t sskdf_size(KDF_SSKDF *ctx)
357 const EVP_MD *md = NULL;
362 md = ossl_prov_digest_md(&ctx->digest);
364 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
367 len = EVP_MD_get_size(md);
368 return (len <= 0) ? 0 : (size_t)len;
371 static int sskdf_derive(void *vctx, unsigned char *key, size_t keylen,
372 const OSSL_PARAM params[])
374 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
377 if (!ossl_prov_is_running() || !sskdf_set_ctx_params(ctx, params))
379 if (ctx->secret == NULL) {
380 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
383 md = ossl_prov_digest_md(&ctx->digest);
385 if (ctx->macctx != NULL) {
386 /* H(x) = KMAC or H(x) = HMAC */
388 const unsigned char *custom = NULL;
389 size_t custom_len = 0;
390 int default_salt_len;
391 EVP_MAC *mac = EVP_MAC_CTX_get0_mac(ctx->macctx);
393 if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_HMAC)) {
394 /* H(x) = HMAC(x, salt, hash) */
396 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
399 default_salt_len = EVP_MD_get_size(md);
400 if (default_salt_len <= 0)
402 } else if (ctx->is_kmac) {
403 /* H(x) = KMACzzz(x, salt, custom) */
404 custom = kmac_custom_str;
405 custom_len = sizeof(kmac_custom_str);
406 if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_KMAC128))
407 default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
409 default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
411 ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_MAC_TYPE);
414 /* If no salt is set then use a default_salt of zeros */
415 if (ctx->salt == NULL || ctx->salt_len <= 0) {
416 ctx->salt = OPENSSL_zalloc(default_salt_len);
417 if (ctx->salt == NULL)
419 ctx->salt_len = default_salt_len;
421 ret = SSKDF_mac_kdm(ctx->macctx,
422 custom, custom_len, ctx->out_len,
423 ctx->salt, ctx->salt_len,
424 ctx->secret, ctx->secret_len,
425 ctx->info, ctx->info_len, key, keylen);
430 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
433 return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
434 ctx->info, ctx->info_len, 0, key, keylen);
438 static int x963kdf_derive(void *vctx, unsigned char *key, size_t keylen,
439 const OSSL_PARAM params[])
441 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
444 if (!ossl_prov_is_running() || !sskdf_set_ctx_params(ctx, params))
447 if (ctx->secret == NULL) {
448 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
452 if (ctx->macctx != NULL) {
453 ERR_raise(ERR_LIB_PROV, PROV_R_NOT_SUPPORTED);
458 md = ossl_prov_digest_md(&ctx->digest);
460 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
464 return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
465 ctx->info, ctx->info_len, 1, key, keylen);
468 static int sskdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
471 KDF_SSKDF *ctx = vctx;
472 OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
479 if (!ossl_prov_macctx_load_from_params(&ctx->macctx, params,
480 NULL, NULL, NULL, libctx))
482 if (ctx->macctx != NULL) {
483 if (EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->macctx),
484 OSSL_MAC_NAME_KMAC128)
485 || EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->macctx),
486 OSSL_MAC_NAME_KMAC256)) {
491 if (!ossl_prov_digest_load_from_params(&ctx->digest, params, libctx))
494 r = ossl_param_get1_octet_string(params, OSSL_KDF_PARAM_SECRET,
495 &ctx->secret, &ctx->secret_len);
497 r = ossl_param_get1_octet_string(params, OSSL_KDF_PARAM_KEY,
498 &ctx->secret, &ctx->secret_len);
502 if (ossl_param_get1_concat_octet_string(params, OSSL_KDF_PARAM_INFO,
503 &ctx->info, &ctx->info_len, 0) == 0)
506 if (ossl_param_get1_octet_string(params, OSSL_KDF_PARAM_SALT,
507 &ctx->salt, &ctx->salt_len) == 0)
510 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MAC_SIZE))
512 if (!OSSL_PARAM_get_size_t(p, &sz) || sz == 0)
519 static const OSSL_PARAM *sskdf_settable_ctx_params(ossl_unused void *ctx,
520 ossl_unused void *provctx)
522 static const OSSL_PARAM known_settable_ctx_params[] = {
523 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
524 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
525 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
526 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
527 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
528 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
529 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
530 OSSL_PARAM_size_t(OSSL_KDF_PARAM_MAC_SIZE, NULL),
533 return known_settable_ctx_params;
536 static int sskdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
538 KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
541 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
542 return OSSL_PARAM_set_size_t(p, sskdf_size(ctx));
546 static const OSSL_PARAM *sskdf_gettable_ctx_params(ossl_unused void *ctx,
547 ossl_unused void *provctx)
549 static const OSSL_PARAM known_gettable_ctx_params[] = {
550 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
553 return known_gettable_ctx_params;
556 const OSSL_DISPATCH ossl_kdf_sskdf_functions[] = {
557 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
558 { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))sskdf_dup },
559 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
560 { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
561 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))sskdf_derive },
562 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
563 (void(*)(void))sskdf_settable_ctx_params },
564 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
565 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
566 (void(*)(void))sskdf_gettable_ctx_params },
567 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
571 const OSSL_DISPATCH ossl_kdf_x963_kdf_functions[] = {
572 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
573 { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))sskdf_dup },
574 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
575 { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
576 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x963kdf_derive },
577 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
578 (void(*)(void))sskdf_settable_ctx_params },
579 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
580 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
581 (void(*)(void))sskdf_gettable_ctx_params },
582 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },