2 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include <openssl/hmac.h>
13 #include <openssl/kdf.h>
14 #include <openssl/evp.h>
15 #include "internal/cryptlib.h"
16 #include "internal/evp_int.h"
18 #define HKDF_MAXBUF 1024
20 static unsigned char *HKDF(const EVP_MD *evp_md,
21 const unsigned char *salt, size_t salt_len,
22 const unsigned char *key, size_t key_len,
23 const unsigned char *info, size_t info_len,
24 unsigned char *okm, size_t okm_len);
26 static unsigned char *HKDF_Extract(const EVP_MD *evp_md,
27 const unsigned char *salt, size_t salt_len,
28 const unsigned char *key, size_t key_len,
29 unsigned char *prk, size_t *prk_len);
31 static unsigned char *HKDF_Expand(const EVP_MD *evp_md,
32 const unsigned char *prk, size_t prk_len,
33 const unsigned char *info, size_t info_len,
34 unsigned char *okm, size_t okm_len);
43 unsigned char info[HKDF_MAXBUF];
47 static int pkey_hkdf_init(EVP_PKEY_CTX *ctx)
51 if ((kctx = OPENSSL_zalloc(sizeof(*kctx))) == NULL) {
52 KDFerr(KDF_F_PKEY_HKDF_INIT, ERR_R_MALLOC_FAILURE);
61 static void pkey_hkdf_cleanup(EVP_PKEY_CTX *ctx)
63 HKDF_PKEY_CTX *kctx = ctx->data;
64 OPENSSL_clear_free(kctx->salt, kctx->salt_len);
65 OPENSSL_clear_free(kctx->key, kctx->key_len);
66 OPENSSL_cleanse(kctx->info, kctx->info_len);
70 static int pkey_hkdf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
72 HKDF_PKEY_CTX *kctx = ctx->data;
75 case EVP_PKEY_CTRL_HKDF_MD:
82 case EVP_PKEY_CTRL_HKDF_MODE:
86 case EVP_PKEY_CTRL_HKDF_SALT:
87 if (p1 == 0 || p2 == NULL)
93 if (kctx->salt != NULL)
94 OPENSSL_clear_free(kctx->salt, kctx->salt_len);
96 kctx->salt = OPENSSL_memdup(p2, p1);
97 if (kctx->salt == NULL)
103 case EVP_PKEY_CTRL_HKDF_KEY:
107 if (kctx->key != NULL)
108 OPENSSL_clear_free(kctx->key, kctx->key_len);
110 kctx->key = OPENSSL_memdup(p2, p1);
111 if (kctx->key == NULL)
117 case EVP_PKEY_CTRL_HKDF_INFO:
118 if (p1 == 0 || p2 == NULL)
121 if (p1 < 0 || p1 > (int)(HKDF_MAXBUF - kctx->info_len))
124 memcpy(kctx->info + kctx->info_len, p2, p1);
125 kctx->info_len += p1;
134 static int pkey_hkdf_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
137 if (strcmp(type, "mode") == 0) {
140 if (strcmp(value, "EXTRACT_AND_EXPAND") == 0)
141 mode = EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND;
142 else if (strcmp(value, "EXTRACT_ONLY") == 0)
143 mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
144 else if (strcmp(value, "EXPAND_ONLY") == 0)
145 mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
149 return EVP_PKEY_CTX_hkdf_mode(ctx, mode);
152 if (strcmp(type, "md") == 0)
153 return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_DERIVE,
154 EVP_PKEY_CTRL_HKDF_MD, value);
156 if (strcmp(type, "salt") == 0)
157 return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);
159 if (strcmp(type, "hexsalt") == 0)
160 return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);
162 if (strcmp(type, "key") == 0)
163 return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);
165 if (strcmp(type, "hexkey") == 0)
166 return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);
168 if (strcmp(type, "info") == 0)
169 return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);
171 if (strcmp(type, "hexinfo") == 0)
172 return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);
174 KDFerr(KDF_F_PKEY_HKDF_CTRL_STR, KDF_R_UNKNOWN_PARAMETER_TYPE);
178 static int pkey_hkdf_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
181 HKDF_PKEY_CTX *kctx = ctx->data;
183 if (kctx->md == NULL) {
184 KDFerr(KDF_F_PKEY_HKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
187 if (kctx->key == NULL) {
188 KDFerr(KDF_F_PKEY_HKDF_DERIVE, KDF_R_MISSING_KEY);
192 switch (kctx->mode) {
193 case EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND:
194 return HKDF(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
195 kctx->key_len, kctx->info, kctx->info_len, key,
198 case EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY:
200 *keylen = EVP_MD_size(kctx->md);
203 return HKDF_Extract(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
204 kctx->key_len, key, keylen) != NULL;
206 case EVP_PKEY_HKDEF_MODE_EXPAND_ONLY:
207 return HKDF_Expand(kctx->md, kctx->key, kctx->key_len, kctx->info,
208 kctx->info_len, key, *keylen) != NULL;
215 const EVP_PKEY_METHOD hkdf_pkey_meth = {
245 static unsigned char *HKDF(const EVP_MD *evp_md,
246 const unsigned char *salt, size_t salt_len,
247 const unsigned char *key, size_t key_len,
248 const unsigned char *info, size_t info_len,
249 unsigned char *okm, size_t okm_len)
251 unsigned char prk[EVP_MAX_MD_SIZE];
255 if (!HKDF_Extract(evp_md, salt, salt_len, key, key_len, prk, &prk_len))
258 ret = HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len);
259 OPENSSL_cleanse(prk, sizeof(prk));
264 static unsigned char *HKDF_Extract(const EVP_MD *evp_md,
265 const unsigned char *salt, size_t salt_len,
266 const unsigned char *key, size_t key_len,
267 unsigned char *prk, size_t *prk_len)
269 unsigned int tmp_len;
271 if (!HMAC(evp_md, salt, salt_len, key, key_len, prk, &tmp_len))
278 static unsigned char *HKDF_Expand(const EVP_MD *evp_md,
279 const unsigned char *prk, size_t prk_len,
280 const unsigned char *info, size_t info_len,
281 unsigned char *okm, size_t okm_len)
287 unsigned char prev[EVP_MAX_MD_SIZE];
289 size_t done_len = 0, dig_len = EVP_MD_size(evp_md);
291 size_t n = okm_len / dig_len;
292 if (okm_len % dig_len)
295 if (n > 255 || okm == NULL)
298 if ((hmac = HMAC_CTX_new()) == NULL)
301 if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL))
304 for (i = 1; i <= n; i++) {
306 const unsigned char ctr = i;
309 if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL))
312 if (!HMAC_Update(hmac, prev, dig_len))
316 if (!HMAC_Update(hmac, info, info_len))
319 if (!HMAC_Update(hmac, &ctr, 1))
322 if (!HMAC_Final(hmac, prev, NULL))
325 copy_len = (done_len + dig_len > okm_len) ?
329 memcpy(okm + done_len, prev, copy_len);
331 done_len += copy_len;