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)
70 static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
71 const unsigned char *z, size_t z_len,
72 const unsigned char *info, size_t info_len,
73 unsigned char *derived_key, size_t derived_key_len)
76 size_t counter, out_len, len = derived_key_len;
78 unsigned char mac[EVP_MAX_MD_SIZE];
79 unsigned char *out = derived_key;
80 EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
82 if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
83 || derived_key_len > SSKDF_MAX_INLEN
84 || derived_key_len == 0)
87 hlen = EVP_MD_size(kdf_md);
90 out_len = (size_t)hlen;
92 ctx = EVP_MD_CTX_create();
93 ctx_init = EVP_MD_CTX_create();
94 if (ctx == NULL || ctx_init == NULL)
97 if (!EVP_DigestInit(ctx_init, kdf_md))
100 for (counter = 1;; counter++) {
101 c[0] = (unsigned char)((counter >> 24) & 0xff);
102 c[1] = (unsigned char)((counter >> 16) & 0xff);
103 c[2] = (unsigned char)((counter >> 8) & 0xff);
104 c[3] = (unsigned char)(counter & 0xff);
106 if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
107 && EVP_DigestUpdate(ctx, c, sizeof(c))
108 && EVP_DigestUpdate(ctx, z, z_len)
109 && EVP_DigestUpdate(ctx, info, info_len)))
111 if (len >= out_len) {
112 if (!EVP_DigestFinal_ex(ctx, out, NULL))
119 if (!EVP_DigestFinal_ex(ctx, mac, NULL))
121 memcpy(out, mac, len);
127 EVP_MD_CTX_destroy(ctx);
128 EVP_MD_CTX_destroy(ctx_init);
129 OPENSSL_cleanse(mac, sizeof(mac));
133 static int kmac_init(EVP_MAC_CTX *ctx, const unsigned char *custom,
134 size_t custom_len, size_t kmac_out_len,
135 size_t derived_key_len, unsigned char **out)
137 /* Only KMAC has custom data - so return if not KMAC */
141 if (!EVP_MAC_ctrl(ctx, EVP_MAC_CTRL_SET_CUSTOM, custom, custom_len))
144 /* By default only do one iteration if kmac_out_len is not specified */
145 if (kmac_out_len == 0)
146 kmac_out_len = derived_key_len;
147 /* otherwise check the size is valid */
148 else if (!(kmac_out_len == derived_key_len
149 || kmac_out_len == 20
150 || kmac_out_len == 28
151 || kmac_out_len == 32
152 || kmac_out_len == 48
153 || kmac_out_len == 64))
156 if (!EVP_MAC_ctrl(ctx, EVP_MAC_CTRL_SET_SIZE, kmac_out_len))
160 * For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
161 * alloc a buffer for this case.
163 if (kmac_out_len > EVP_MAX_MD_SIZE) {
164 *out = OPENSSL_zalloc(kmac_out_len);
172 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
173 * Section 4. One-Step Key Derivation using MAC: i.e either
174 * H(x) = HMAC-hash(salt, x) OR
175 * H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
177 static int SSKDF_mac_kdm(const EVP_MAC *kdf_mac, const EVP_MD *hmac_md,
178 const unsigned char *kmac_custom,
179 size_t kmac_custom_len, size_t kmac_out_len,
180 const unsigned char *salt, size_t salt_len,
181 const unsigned char *z, size_t z_len,
182 const unsigned char *info, size_t info_len,
183 unsigned char *derived_key, size_t derived_key_len)
186 size_t counter, out_len, len;
188 unsigned char mac_buf[EVP_MAX_MD_SIZE];
189 unsigned char *out = derived_key;
190 EVP_MAC_CTX *ctx = NULL, *ctx_init = NULL;
191 unsigned char *mac = mac_buf, *kmac_buffer = NULL;
193 if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
194 || derived_key_len > SSKDF_MAX_INLEN
195 || derived_key_len == 0)
198 ctx = EVP_MAC_CTX_new(kdf_mac);
199 ctx_init = EVP_MAC_CTX_new(kdf_mac);
200 if (ctx == NULL || ctx_init == NULL)
202 if (hmac_md != NULL &&
203 !EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_MD, hmac_md))
206 if (!EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_KEY, salt, salt_len))
209 if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
210 derived_key_len, &kmac_buffer))
212 if (kmac_buffer != NULL)
215 if (!EVP_MAC_init(ctx_init))
218 out_len = EVP_MAC_size(ctx_init); /* output size */
221 len = derived_key_len;
223 for (counter = 1;; counter++) {
224 c[0] = (unsigned char)((counter >> 24) & 0xff);
225 c[1] = (unsigned char)((counter >> 16) & 0xff);
226 c[2] = (unsigned char)((counter >> 8) & 0xff);
227 c[3] = (unsigned char)(counter & 0xff);
229 if (!(EVP_MAC_CTX_copy(ctx, ctx_init)
230 && EVP_MAC_update(ctx, c, sizeof(c))
231 && EVP_MAC_update(ctx, z, z_len)
232 && EVP_MAC_update(ctx, info, info_len)))
234 if (len >= out_len) {
235 if (!EVP_MAC_final(ctx, out, NULL))
242 if (!EVP_MAC_final(ctx, mac, NULL))
244 memcpy(out, mac, len);
250 OPENSSL_free(kmac_buffer);
251 EVP_MAC_CTX_free(ctx);
252 EVP_MAC_CTX_free(ctx_init);
253 OPENSSL_cleanse(mac, sizeof(mac));
257 static EVP_KDF_IMPL *sskdf_new(void)
261 if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
262 KDFerr(KDF_F_SSKDF_NEW, ERR_R_MALLOC_FAILURE);
266 static void sskdf_reset(EVP_KDF_IMPL *impl)
268 OPENSSL_clear_free(impl->secret, impl->secret_len);
269 OPENSSL_clear_free(impl->info, impl->info_len);
270 OPENSSL_clear_free(impl->salt, impl->salt_len);
271 memset(impl, 0, sizeof(*impl));
274 static void sskdf_free(EVP_KDF_IMPL *impl)
280 static int sskdf_set_buffer(va_list args, unsigned char **out, size_t *out_len)
282 const unsigned char *p;
285 p = va_arg(args, const unsigned char *);
286 len = va_arg(args, size_t);
287 if (len == 0 || p == NULL)
291 *out = OPENSSL_memdup(p, len);
299 static int sskdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
305 case EVP_KDF_CTRL_SET_KEY:
306 return sskdf_set_buffer(args, &impl->secret, &impl->secret_len);
308 case EVP_KDF_CTRL_SET_SSKDF_INFO:
309 return sskdf_set_buffer(args, &impl->info, &impl->info_len);
311 case EVP_KDF_CTRL_SET_MD:
312 md = va_arg(args, const EVP_MD *);
319 case EVP_KDF_CTRL_SET_MAC:
320 mac = va_arg(args, const EVP_MAC *);
327 case EVP_KDF_CTRL_SET_SALT:
328 return sskdf_set_buffer(args, &impl->salt, &impl->salt_len);
330 case EVP_KDF_CTRL_SET_MAC_SIZE:
331 impl->out_len = va_arg(args, size_t);
339 /* Pass a mac to a ctrl */
340 static int sskdf_mac2ctrl(EVP_KDF_IMPL *impl,
341 int (*ctrl)(EVP_KDF_IMPL *impl, int cmd, va_list args),
342 int cmd, const char *mac_name)
346 if (mac_name == NULL || (mac = EVP_get_macbyname(mac_name)) == NULL) {
347 KDFerr(KDF_F_SSKDF_MAC2CTRL, KDF_R_INVALID_MAC_TYPE);
350 return call_ctrl(ctrl, impl, cmd, mac);
353 static int sskdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
356 if (strcmp(type, "secret") == 0 || strcmp(type, "key") == 0)
357 return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_KEY,
360 if (strcmp(type, "hexsecret") == 0 || strcmp(type, "hexkey") == 0)
361 return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_KEY,
364 if (strcmp(type, "info") == 0)
365 return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SSKDF_INFO,
368 if (strcmp(type, "hexinfo") == 0)
369 return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SSKDF_INFO,
372 if (strcmp(type, "digest") == 0)
373 return kdf_md2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_MD, value);
375 if (strcmp(type, "mac") == 0)
376 return sskdf_mac2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_MAC, value);
378 if (strcmp(type, "salt") == 0)
379 return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);
381 if (strcmp(type, "hexsalt") == 0)
382 return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);
385 if (strcmp(type, "maclen") == 0) {
386 int val = atoi(value);
388 KDFerr(KDF_F_SSKDF_CTRL_STR, KDF_R_VALUE_ERROR);
391 return call_ctrl(sskdf_ctrl, impl, EVP_KDF_CTRL_SET_MAC_SIZE,
397 static size_t sskdf_size(EVP_KDF_IMPL *impl)
401 if (impl->md == NULL) {
402 KDFerr(KDF_F_SSKDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
405 len = EVP_MD_size(impl->md);
406 return (len <= 0) ? 0 : (size_t)len;
409 static int sskdf_derive(EVP_KDF_IMPL *impl, unsigned char *key, size_t keylen)
411 if (impl->secret == NULL) {
412 KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_SECRET);
416 if (impl->mac != NULL) {
417 /* H(x) = KMAC or H(x) = HMAC */
419 const unsigned char *custom = NULL;
420 size_t custom_len = 0;
422 int default_salt_len;
424 nid = EVP_MAC_nid(impl->mac);
425 if (nid == EVP_MAC_HMAC) {
426 /* H(x) = HMAC(x, salt, hash) */
427 if (impl->md == NULL) {
428 KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
431 default_salt_len = EVP_MD_block_size(impl->md);
432 if (default_salt_len <= 0)
434 } else if (nid == EVP_MAC_KMAC128 || nid == EVP_MAC_KMAC256) {
435 /* H(x) = KMACzzz(x, salt, custom) */
436 custom = kmac_custom_str;
437 custom_len = sizeof(kmac_custom_str);
438 if (nid == EVP_MAC_KMAC128)
439 default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
441 default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
443 KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_UNSUPPORTED_MAC_TYPE);
446 /* If no salt is set then use a default_salt of zeros */
447 if (impl->salt == NULL || impl->salt_len <= 0) {
448 impl->salt = OPENSSL_zalloc(default_salt_len);
449 if (impl->salt == NULL) {
450 KDFerr(KDF_F_SSKDF_DERIVE, ERR_R_MALLOC_FAILURE);
453 impl->salt_len = default_salt_len;
455 ret = SSKDF_mac_kdm(impl->mac, impl->md,
456 custom, custom_len, impl->out_len,
457 impl->salt, impl->salt_len,
458 impl->secret, impl->secret_len,
459 impl->info, impl->info_len, key, keylen);
463 if (impl->md == NULL) {
464 KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
467 return SSKDF_hash_kdm(impl->md, impl->secret, impl->secret_len,
468 impl->info, impl->info_len, key, keylen);
472 const EVP_KDF_METHOD ss_kdf_meth = {