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 kctx = OPENSSL_zalloc(sizeof(*kctx));
60 static void pkey_hkdf_cleanup(EVP_PKEY_CTX *ctx)
62 HKDF_PKEY_CTX *kctx = ctx->data;
63 OPENSSL_clear_free(kctx->salt, kctx->salt_len);
64 OPENSSL_clear_free(kctx->key, kctx->key_len);
65 OPENSSL_cleanse(kctx->info, kctx->info_len);
69 static int pkey_hkdf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
71 HKDF_PKEY_CTX *kctx = ctx->data;
74 case EVP_PKEY_CTRL_HKDF_MD:
81 case EVP_PKEY_CTRL_HKDF_MODE:
85 case EVP_PKEY_CTRL_HKDF_SALT:
86 if (p1 == 0 || p2 == NULL)
92 if (kctx->salt != NULL)
93 OPENSSL_clear_free(kctx->salt, kctx->salt_len);
95 kctx->salt = OPENSSL_memdup(p2, p1);
96 if (kctx->salt == NULL)
102 case EVP_PKEY_CTRL_HKDF_KEY:
106 if (kctx->key != NULL)
107 OPENSSL_clear_free(kctx->key, kctx->key_len);
109 kctx->key = OPENSSL_memdup(p2, p1);
110 if (kctx->key == NULL)
116 case EVP_PKEY_CTRL_HKDF_INFO:
117 if (p1 == 0 || p2 == NULL)
120 if (p1 < 0 || p1 > (int)(HKDF_MAXBUF - kctx->info_len))
123 memcpy(kctx->info + kctx->info_len, p2, p1);
124 kctx->info_len += p1;
133 static int pkey_hkdf_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
136 if (strcmp(type, "mode") == 0) {
139 if (strcmp(value, "EXTRACT_AND_EXPAND") == 0)
140 mode = EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND;
141 else if (strcmp(value, "EXTRACT_ONLY") == 0)
142 mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
143 else if (strcmp(value, "EXPAND_ONLY") == 0)
144 mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
148 return EVP_PKEY_CTX_hkdf_mode(ctx, mode);
151 if (strcmp(type, "md") == 0)
152 return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_DERIVE,
153 EVP_PKEY_CTRL_HKDF_MD, value);
155 if (strcmp(type, "salt") == 0)
156 return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);
158 if (strcmp(type, "hexsalt") == 0)
159 return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);
161 if (strcmp(type, "key") == 0)
162 return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);
164 if (strcmp(type, "hexkey") == 0)
165 return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);
167 if (strcmp(type, "info") == 0)
168 return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);
170 if (strcmp(type, "hexinfo") == 0)
171 return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);
173 KDFerr(KDF_F_PKEY_HKDF_CTRL_STR, KDF_R_UNKNOWN_PARAMETER_TYPE);
177 static int pkey_hkdf_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
180 HKDF_PKEY_CTX *kctx = ctx->data;
182 if (kctx->md == NULL) {
183 KDFerr(KDF_F_PKEY_HKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
186 if (kctx->key == NULL) {
187 KDFerr(KDF_F_PKEY_HKDF_DERIVE, KDF_R_MISSING_KEY);
191 switch (kctx->mode) {
192 case EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND:
193 return HKDF(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
194 kctx->key_len, kctx->info, kctx->info_len, key,
197 case EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY:
199 *keylen = EVP_MD_size(kctx->md);
202 return HKDF_Extract(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
203 kctx->key_len, key, keylen) != NULL;
205 case EVP_PKEY_HKDEF_MODE_EXPAND_ONLY:
206 return HKDF_Expand(kctx->md, kctx->key, kctx->key_len, kctx->info,
207 kctx->info_len, key, *keylen) != NULL;
214 const EVP_PKEY_METHOD hkdf_pkey_meth = {
244 static unsigned char *HKDF(const EVP_MD *evp_md,
245 const unsigned char *salt, size_t salt_len,
246 const unsigned char *key, size_t key_len,
247 const unsigned char *info, size_t info_len,
248 unsigned char *okm, size_t okm_len)
250 unsigned char prk[EVP_MAX_MD_SIZE];
254 if (!HKDF_Extract(evp_md, salt, salt_len, key, key_len, prk, &prk_len))
257 ret = HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len);
258 OPENSSL_cleanse(prk, sizeof(prk));
263 static unsigned char *HKDF_Extract(const EVP_MD *evp_md,
264 const unsigned char *salt, size_t salt_len,
265 const unsigned char *key, size_t key_len,
266 unsigned char *prk, size_t *prk_len)
268 unsigned int tmp_len;
270 if (!HMAC(evp_md, salt, salt_len, key, key_len, prk, &tmp_len))
277 static unsigned char *HKDF_Expand(const EVP_MD *evp_md,
278 const unsigned char *prk, size_t prk_len,
279 const unsigned char *info, size_t info_len,
280 unsigned char *okm, size_t okm_len)
286 unsigned char prev[EVP_MAX_MD_SIZE];
288 size_t done_len = 0, dig_len = EVP_MD_size(evp_md);
290 size_t n = okm_len / dig_len;
291 if (okm_len % dig_len)
294 if (n > 255 || okm == NULL)
297 if ((hmac = HMAC_CTX_new()) == NULL)
300 if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL))
303 for (i = 1; i <= n; i++) {
305 const unsigned char ctr = i;
308 if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL))
311 if (!HMAC_Update(hmac, prev, dig_len))
315 if (!HMAC_Update(hmac, info, info_len))
318 if (!HMAC_Update(hmac, &ctr, 1))
321 if (!HMAC_Final(hmac, prev, NULL))
324 copy_len = (done_len + dig_len > okm_len) ?
328 memcpy(okm + done_len, prev, copy_len);
330 done_len += copy_len;