crypto/kdf/hkdf.c - third_party/openssl - Git at Google

 /*
  * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
  */

 #include <stdlib.h>
 #include <stdarg.h>
 #include <string.h>
 #include <openssl/hmac.h>
 #include <openssl/evp.h>
 #include <openssl/kdf.h>
 #include "internal/cryptlib.h"
 #include "internal/numbers.h"
 #include "internal/evp_int.h"
 #include "kdf_local.h"

 #define HKDF_MAXBUF 1024

 static void kdf_hkdf_reset(EVP_KDF_IMPL *impl);
 static int HKDF(const EVP_MD *evp_md,
                 const unsigned char *salt, size_t salt_len,
                 const unsigned char *key, size_t key_len,
                 const unsigned char *info, size_t info_len,
                 unsigned char *okm, size_t okm_len);
 static int HKDF_Extract(const EVP_MD *evp_md,
                         const unsigned char *salt, size_t salt_len,
                         const unsigned char *key, size_t key_len,
                         unsigned char *prk, size_t prk_len);
 static int HKDF_Expand(const EVP_MD *evp_md,
                        const unsigned char *prk, size_t prk_len,
                        const unsigned char *info, size_t info_len,
                        unsigned char *okm, size_t okm_len);

 struct evp_kdf_impl_st {
     int mode;
     const EVP_MD *md;
     unsigned char *salt;
     size_t salt_len;
     unsigned char *key;
     size_t key_len;
     unsigned char info[HKDF_MAXBUF];
     size_t info_len;
 };

 static EVP_KDF_IMPL *kdf_hkdf_new(void)
 {
     EVP_KDF_IMPL *impl;

     if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
         KDFerr(KDF_F_KDF_HKDF_NEW, ERR_R_MALLOC_FAILURE);
     return impl;
 }

 static void kdf_hkdf_free(EVP_KDF_IMPL *impl)
 {
     kdf_hkdf_reset(impl);
     OPENSSL_free(impl);
 }

 static void kdf_hkdf_reset(EVP_KDF_IMPL *impl)
 {
     OPENSSL_free(impl->salt);
     OPENSSL_clear_free(impl->key, impl->key_len);
     OPENSSL_cleanse(impl->info, impl->info_len);
     memset(impl, 0, sizeof(*impl));
 }

 static int kdf_hkdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
 {
     const unsigned char *p;
     size_t len;
     const EVP_MD *md;

     switch (cmd) {
     case EVP_KDF_CTRL_SET_MD:
         md = va_arg(args, const EVP_MD *);
         if (md == NULL)
             return 0;

         impl->md = md;
         return 1;

     case EVP_KDF_CTRL_SET_HKDF_MODE:
         impl->mode = va_arg(args, int);
         return 1;

     case EVP_KDF_CTRL_SET_SALT:
         p = va_arg(args, const unsigned char *);
         len = va_arg(args, size_t);
         if (len == 0 || p == NULL)
             return 1;

         OPENSSL_free(impl->salt);
         impl->salt = OPENSSL_memdup(p, len);
         if (impl->salt == NULL)
             return 0;

         impl->salt_len = len;
         return 1;

     case EVP_KDF_CTRL_SET_KEY:
         p = va_arg(args, const unsigned char *);
         len = va_arg(args, size_t);
         OPENSSL_clear_free(impl->key, impl->key_len);
         impl->key = OPENSSL_memdup(p, len);
         if (impl->key == NULL)
             return 0;

         impl->key_len  = len;
         return 1;

     case EVP_KDF_CTRL_RESET_HKDF_INFO:
         OPENSSL_cleanse(impl->info, impl->info_len);
         impl->info_len = 0;
         return 1;

     case EVP_KDF_CTRL_ADD_HKDF_INFO:
         p = va_arg(args, const unsigned char *);
         len = va_arg(args, size_t);
         if (len == 0 || p == NULL)
             return 1;

         if (len > (HKDF_MAXBUF - impl->info_len))
             return 0;

         memcpy(impl->info + impl->info_len, p, len);
         impl->info_len += len;
         return 1;

     default:
         return -2;
     }
 }

 static int kdf_hkdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
                              const char *value)
 {
     if (strcmp(type, "mode") == 0) {
         int mode;

         if (strcmp(value, "EXTRACT_AND_EXPAND") == 0)
             mode = EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND;
         else if (strcmp(value, "EXTRACT_ONLY") == 0)
             mode = EVP_KDF_HKDF_MODE_EXTRACT_ONLY;
         else if (strcmp(value, "EXPAND_ONLY") == 0)
             mode = EVP_KDF_HKDF_MODE_EXPAND_ONLY;
         else
             return 0;

         return call_ctrl(kdf_hkdf_ctrl, impl, EVP_KDF_CTRL_SET_HKDF_MODE, mode);
     }

     if (strcmp(type, "digest") == 0)
         return kdf_md2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_MD, value);

     if (strcmp(type, "salt") == 0)
         return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);

     if (strcmp(type, "hexsalt") == 0)
         return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);

     if (strcmp(type, "key") == 0)
         return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_KEY, value);

     if (strcmp(type, "hexkey") == 0)
         return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_KEY, value);

     if (strcmp(type, "info") == 0)
         return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_ADD_HKDF_INFO,
                             value);

     if (strcmp(type, "hexinfo") == 0)
         return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_ADD_HKDF_INFO,
                             value);

     return -2;
 }

 static size_t kdf_hkdf_size(EVP_KDF_IMPL *impl)
 {
     if (impl->mode != EVP_KDF_HKDF_MODE_EXTRACT_ONLY)
         return SIZE_MAX;

     if (impl->md == NULL) {
         KDFerr(KDF_F_KDF_HKDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
         return 0;
     }
     return EVP_MD_size(impl->md);
 }

 static int kdf_hkdf_derive(EVP_KDF_IMPL *impl, unsigned char *key,
                            size_t keylen)
 {
     if (impl->md == NULL) {
         KDFerr(KDF_F_KDF_HKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
         return 0;
     }
     if (impl->key == NULL) {
         KDFerr(KDF_F_KDF_HKDF_DERIVE, KDF_R_MISSING_KEY);
         return 0;
     }

     switch (impl->mode) {
     case EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND:
         return HKDF(impl->md, impl->salt, impl->salt_len, impl->key,
                     impl->key_len, impl->info, impl->info_len, key,
                     keylen);

     case EVP_KDF_HKDF_MODE_EXTRACT_ONLY:
         return HKDF_Extract(impl->md, impl->salt, impl->salt_len, impl->key,
                             impl->key_len, key, keylen);

     case EVP_KDF_HKDF_MODE_EXPAND_ONLY:
         return HKDF_Expand(impl->md, impl->key, impl->key_len, impl->info,
                            impl->info_len, key, keylen);

     default:
         return 0;
     }
 }

 const EVP_KDF_METHOD hkdf_kdf_meth = {
     EVP_KDF_HKDF,
     kdf_hkdf_new,
     kdf_hkdf_free,
     kdf_hkdf_reset,
     kdf_hkdf_ctrl,
     kdf_hkdf_ctrl_str,
     kdf_hkdf_size,
     kdf_hkdf_derive
 };

 static int HKDF(const EVP_MD *evp_md,
                 const unsigned char *salt, size_t salt_len,
                 const unsigned char *key, size_t key_len,
                 const unsigned char *info, size_t info_len,
                 unsigned char *okm, size_t okm_len)
 {
     unsigned char prk[EVP_MAX_MD_SIZE];
     int ret;
     size_t prk_len = EVP_MD_size(evp_md);

     if (!HKDF_Extract(evp_md, salt, salt_len, key, key_len, prk, prk_len))
         return 0;

     ret = HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len);
     OPENSSL_cleanse(prk, sizeof(prk));

     return ret;
 }

 static int HKDF_Extract(const EVP_MD *evp_md,
                         const unsigned char *salt, size_t salt_len,
                         const unsigned char *key, size_t key_len,
                         unsigned char *prk, size_t prk_len)
 {
     if (prk_len != (size_t)EVP_MD_size(evp_md)) {
         KDFerr(KDF_F_HKDF_EXTRACT, KDF_R_WRONG_OUTPUT_BUFFER_SIZE);
         return 0;
     }
     return HMAC(evp_md, salt, salt_len, key, key_len, prk, NULL) != NULL;
 }

 static int HKDF_Expand(const EVP_MD *evp_md,
                        const unsigned char *prk, size_t prk_len,
                        const unsigned char *info, size_t info_len,
                        unsigned char *okm, size_t okm_len)
 {
     HMAC_CTX *hmac;
     int ret = 0;
     unsigned int i;
     unsigned char prev[EVP_MAX_MD_SIZE];
     size_t done_len = 0, dig_len = EVP_MD_size(evp_md);
     size_t n = okm_len / dig_len;

     if (okm_len % dig_len)
         n++;

     if (n > 255 || okm == NULL)
         return 0;

     if ((hmac = HMAC_CTX_new()) == NULL)
         return 0;

     if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL))
         goto err;

     for (i = 1; i <= n; i++) {
         size_t copy_len;
         const unsigned char ctr = i;

         if (i > 1) {
             if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL))
                 goto err;

             if (!HMAC_Update(hmac, prev, dig_len))
                 goto err;
         }

         if (!HMAC_Update(hmac, info, info_len))
             goto err;

         if (!HMAC_Update(hmac, &ctr, 1))
             goto err;

         if (!HMAC_Final(hmac, prev, NULL))
             goto err;

         copy_len = (done_len + dig_len > okm_len) ?
                        okm_len - done_len :
                        dig_len;

         memcpy(okm + done_len, prev, copy_len);

         done_len += copy_len;
     }
     ret = 1;

  err:
     OPENSSL_cleanse(prev, sizeof(prev));
     HMAC_CTX_free(hmac);
     return ret;
 }
	/*
	* Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
	*
	* Licensed under the Apache License 2.0 (the "License"). You may not use
	* this file except in compliance with the License. You can obtain a copy
	* in the file LICENSE in the source distribution or at
	* https://www.openssl.org/source/license.html
	*/

	#include <stdlib.h>
	#include <stdarg.h>
	#include <string.h>
	#include <openssl/hmac.h>
	#include <openssl/evp.h>
	#include <openssl/kdf.h>
	#include "internal/cryptlib.h"
	#include "internal/numbers.h"
	#include "internal/evp_int.h"
	#include "kdf_local.h"

	#define HKDF_MAXBUF 1024

	static void kdf_hkdf_reset(EVP_KDF_IMPL *impl);
	static int HKDF(const EVP_MD *evp_md,
	const unsigned char *salt, size_t salt_len,
	const unsigned char *key, size_t key_len,
	const unsigned char *info, size_t info_len,
	unsigned char *okm, size_t okm_len);
	static int HKDF_Extract(const EVP_MD *evp_md,
	const unsigned char *salt, size_t salt_len,
	const unsigned char *key, size_t key_len,
	unsigned char *prk, size_t prk_len);
	static int HKDF_Expand(const EVP_MD *evp_md,
	const unsigned char *prk, size_t prk_len,
	const unsigned char *info, size_t info_len,
	unsigned char *okm, size_t okm_len);

	struct evp_kdf_impl_st {
	int mode;
	const EVP_MD *md;
	unsigned char *salt;
	size_t salt_len;
	unsigned char *key;
	size_t key_len;
	unsigned char info[HKDF_MAXBUF];
	size_t info_len;
	};

	static EVP_KDF_IMPL *kdf_hkdf_new(void)
	{
	EVP_KDF_IMPL *impl;

	if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
	KDFerr(KDF_F_KDF_HKDF_NEW, ERR_R_MALLOC_FAILURE);
	return impl;
	}

	static void kdf_hkdf_free(EVP_KDF_IMPL *impl)
	{
	kdf_hkdf_reset(impl);
	OPENSSL_free(impl);
	}

	static void kdf_hkdf_reset(EVP_KDF_IMPL *impl)
	{
	OPENSSL_free(impl->salt);
	OPENSSL_clear_free(impl->key, impl->key_len);
	OPENSSL_cleanse(impl->info, impl->info_len);
	memset(impl, 0, sizeof(*impl));
	}

	static int kdf_hkdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
	{
	const unsigned char *p;
	size_t len;
	const EVP_MD *md;

	switch (cmd) {
	case EVP_KDF_CTRL_SET_MD:
	md = va_arg(args, const EVP_MD *);
	if (md == NULL)
	return 0;

	impl->md = md;
	return 1;

	case EVP_KDF_CTRL_SET_HKDF_MODE:
	impl->mode = va_arg(args, int);
	return 1;

	case EVP_KDF_CTRL_SET_SALT:
	p = va_arg(args, const unsigned char *);
	len = va_arg(args, size_t);
	if (len == 0 \|\| p == NULL)
	return 1;

	OPENSSL_free(impl->salt);
	impl->salt = OPENSSL_memdup(p, len);
	if (impl->salt == NULL)
	return 0;

	impl->salt_len = len;
	return 1;

	case EVP_KDF_CTRL_SET_KEY:
	p = va_arg(args, const unsigned char *);
	len = va_arg(args, size_t);
	OPENSSL_clear_free(impl->key, impl->key_len);
	impl->key = OPENSSL_memdup(p, len);
	if (impl->key == NULL)
	return 0;

	impl->key_len = len;
	return 1;

	case EVP_KDF_CTRL_RESET_HKDF_INFO:
	OPENSSL_cleanse(impl->info, impl->info_len);
	impl->info_len = 0;
	return 1;

	case EVP_KDF_CTRL_ADD_HKDF_INFO:
	p = va_arg(args, const unsigned char *);
	len = va_arg(args, size_t);
	if (len == 0 \|\| p == NULL)
	return 1;

	if (len > (HKDF_MAXBUF - impl->info_len))
	return 0;

	memcpy(impl->info + impl->info_len, p, len);
	impl->info_len += len;
	return 1;

	default:
	return -2;
	}
	}

	static int kdf_hkdf_ctrl_str(EVP_KDF_IMPL impl, const char type,
	const char *value)
	{
	if (strcmp(type, "mode") == 0) {
	int mode;

	if (strcmp(value, "EXTRACT_AND_EXPAND") == 0)
	mode = EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND;
	else if (strcmp(value, "EXTRACT_ONLY") == 0)
	mode = EVP_KDF_HKDF_MODE_EXTRACT_ONLY;
	else if (strcmp(value, "EXPAND_ONLY") == 0)
	mode = EVP_KDF_HKDF_MODE_EXPAND_ONLY;
	else
	return 0;

	return call_ctrl(kdf_hkdf_ctrl, impl, EVP_KDF_CTRL_SET_HKDF_MODE, mode);
	}

	if (strcmp(type, "digest") == 0)
	return kdf_md2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_MD, value);

	if (strcmp(type, "salt") == 0)
	return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);

	if (strcmp(type, "hexsalt") == 0)
	return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);

	if (strcmp(type, "key") == 0)
	return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_KEY, value);

	if (strcmp(type, "hexkey") == 0)
	return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_KEY, value);

	if (strcmp(type, "info") == 0)
	return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_ADD_HKDF_INFO,
	value);

	if (strcmp(type, "hexinfo") == 0)
	return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_ADD_HKDF_INFO,
	value);

	return -2;
	}

	static size_t kdf_hkdf_size(EVP_KDF_IMPL *impl)
	{
	if (impl->mode != EVP_KDF_HKDF_MODE_EXTRACT_ONLY)
	return SIZE_MAX;

	if (impl->md == NULL) {
	KDFerr(KDF_F_KDF_HKDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
	return 0;
	}
	return EVP_MD_size(impl->md);
	}

	static int kdf_hkdf_derive(EVP_KDF_IMPL impl, unsigned char key,
	size_t keylen)
	{
	if (impl->md == NULL) {
	KDFerr(KDF_F_KDF_HKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
	return 0;
	}
	if (impl->key == NULL) {
	KDFerr(KDF_F_KDF_HKDF_DERIVE, KDF_R_MISSING_KEY);
	return 0;
	}

	switch (impl->mode) {
	case EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND:
	return HKDF(impl->md, impl->salt, impl->salt_len, impl->key,
	impl->key_len, impl->info, impl->info_len, key,
	keylen);

	case EVP_KDF_HKDF_MODE_EXTRACT_ONLY:
	return HKDF_Extract(impl->md, impl->salt, impl->salt_len, impl->key,
	impl->key_len, key, keylen);

	case EVP_KDF_HKDF_MODE_EXPAND_ONLY:
	return HKDF_Expand(impl->md, impl->key, impl->key_len, impl->info,
	impl->info_len, key, keylen);

	default:
	return 0;
	}
	}

	const EVP_KDF_METHOD hkdf_kdf_meth = {
	EVP_KDF_HKDF,
	kdf_hkdf_new,
	kdf_hkdf_free,
	kdf_hkdf_reset,
	kdf_hkdf_ctrl,
	kdf_hkdf_ctrl_str,
	kdf_hkdf_size,
	kdf_hkdf_derive
	};

	static int HKDF(const EVP_MD *evp_md,
	const unsigned char *salt, size_t salt_len,
	const unsigned char *key, size_t key_len,
	const unsigned char *info, size_t info_len,
	unsigned char *okm, size_t okm_len)
	{
	unsigned char prk[EVP_MAX_MD_SIZE];
	int ret;
	size_t prk_len = EVP_MD_size(evp_md);

	if (!HKDF_Extract(evp_md, salt, salt_len, key, key_len, prk, prk_len))
	return 0;

	ret = HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len);
	OPENSSL_cleanse(prk, sizeof(prk));

	return ret;
	}

	static int HKDF_Extract(const EVP_MD *evp_md,
	const unsigned char *salt, size_t salt_len,
	const unsigned char *key, size_t key_len,
	unsigned char *prk, size_t prk_len)
	{
	if (prk_len != (size_t)EVP_MD_size(evp_md)) {
	KDFerr(KDF_F_HKDF_EXTRACT, KDF_R_WRONG_OUTPUT_BUFFER_SIZE);
	return 0;
	}
	return HMAC(evp_md, salt, salt_len, key, key_len, prk, NULL) != NULL;
	}

	static int HKDF_Expand(const EVP_MD *evp_md,
	const unsigned char *prk, size_t prk_len,
	const unsigned char *info, size_t info_len,
	unsigned char *okm, size_t okm_len)
	{
	HMAC_CTX *hmac;
	int ret = 0;
	unsigned int i;
	unsigned char prev[EVP_MAX_MD_SIZE];
	size_t done_len = 0, dig_len = EVP_MD_size(evp_md);
	size_t n = okm_len / dig_len;

	if (okm_len % dig_len)
	n++;

	if (n > 255 \|\| okm == NULL)
	return 0;

	if ((hmac = HMAC_CTX_new()) == NULL)
	return 0;

	if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL))
	goto err;

	for (i = 1; i <= n; i++) {
	size_t copy_len;
	const unsigned char ctr = i;

	if (i > 1) {
	if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL))
	goto err;

	if (!HMAC_Update(hmac, prev, dig_len))
	goto err;
	}

	if (!HMAC_Update(hmac, info, info_len))
	goto err;

	if (!HMAC_Update(hmac, &ctr, 1))
	goto err;

	if (!HMAC_Final(hmac, prev, NULL))
	goto err;

	copy_len = (done_len + dig_len > okm_len) ?
	okm_len - done_len :
	dig_len;

	memcpy(okm + done_len, prev, copy_len);

	done_len += copy_len;
	}
	ret = 1;

	err:
	OPENSSL_cleanse(prev, sizeof(prev));
	HMAC_CTX_free(hmac);
	return ret;
	}