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

 /*
  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (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 <string.h>
 #include <openssl/hmac.h>
 #include <openssl/kdf.h>
 #include <openssl/evp.h>
 #include "internal/cryptlib.h"
 #include "internal/evp_int.h"

 #define HKDF_MAXBUF 1024

 static unsigned char *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 unsigned char *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 unsigned char *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);

 typedef struct {
     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;
 } HKDF_PKEY_CTX;

 static int pkey_hkdf_init(EVP_PKEY_CTX *ctx)
 {
     HKDF_PKEY_CTX *kctx;

     kctx = OPENSSL_zalloc(sizeof(*kctx));
     if (kctx == NULL)
         return 0;

     ctx->data = kctx;

     return 1;
 }

 static void pkey_hkdf_cleanup(EVP_PKEY_CTX *ctx)
 {
     HKDF_PKEY_CTX *kctx = ctx->data;
     OPENSSL_clear_free(kctx->salt, kctx->salt_len);
     OPENSSL_clear_free(kctx->key, kctx->key_len);
     OPENSSL_cleanse(kctx->info, kctx->info_len);
     OPENSSL_free(kctx);
 }

 static int pkey_hkdf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 {
     HKDF_PKEY_CTX *kctx = ctx->data;

     switch (type) {
     case EVP_PKEY_CTRL_HKDF_MD:
         if (p2 == NULL)
             return 0;

         kctx->md = p2;
         return 1;

     case EVP_PKEY_CTRL_HKDF_MODE:
         kctx->mode = p1;
         return 1;

     case EVP_PKEY_CTRL_HKDF_SALT:
         if (p1 == 0 || p2 == NULL)
             return 1;

         if (p1 < 0)
             return 0;

         if (kctx->salt != NULL)
             OPENSSL_clear_free(kctx->salt, kctx->salt_len);

         kctx->salt = OPENSSL_memdup(p2, p1);
         if (kctx->salt == NULL)
             return 0;

         kctx->salt_len = p1;
         return 1;

     case EVP_PKEY_CTRL_HKDF_KEY:
         if (p1 < 0)
             return 0;

         if (kctx->key != NULL)
             OPENSSL_clear_free(kctx->key, kctx->key_len);

         kctx->key = OPENSSL_memdup(p2, p1);
         if (kctx->key == NULL)
             return 0;

         kctx->key_len  = p1;
         return 1;

     case EVP_PKEY_CTRL_HKDF_INFO:
         if (p1 == 0 || p2 == NULL)
             return 1;

         if (p1 < 0 || p1 > (int)(HKDF_MAXBUF - kctx->info_len))
             return 0;

         memcpy(kctx->info + kctx->info_len, p2, p1);
         kctx->info_len += p1;
         return 1;

     default:
         return -2;

     }
 }

 static int pkey_hkdf_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
                               const char *value)
 {
     if (strcmp(type, "mode") == 0) {
         int mode;

         if (strcmp(value, "EXTRACT_AND_EXPAND") == 0)
             mode = EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND;
         else if (strcmp(value, "EXTRACT_ONLY") == 0)
             mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
         else if (strcmp(value, "EXPAND_ONLY") == 0)
             mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
         else
             return 0;

         return EVP_PKEY_CTX_hkdf_mode(ctx, mode);
     }

     if (strcmp(type, "md") == 0)
         return EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_get_digestbyname(value));

     if (strcmp(type, "salt") == 0)
         return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);

     if (strcmp(type, "hexsalt") == 0)
         return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);

     if (strcmp(type, "key") == 0)
         return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);

     if (strcmp(type, "hexkey") == 0)
         return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);

     if (strcmp(type, "info") == 0)
         return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);

     if (strcmp(type, "hexinfo") == 0)
         return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);

     return -2;
 }

 static int pkey_hkdf_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
                             size_t *keylen)
 {
     HKDF_PKEY_CTX *kctx = ctx->data;

     if (kctx->md == NULL || kctx->key == NULL)
         return 0;

     switch (kctx->mode) {
     case EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND:
         return HKDF(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
                     kctx->key_len, kctx->info, kctx->info_len, key,
                     *keylen) != NULL;

     case EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY:
         if (key == NULL) {
             *keylen = EVP_MD_size(kctx->md);
             return 1;
         }
         return HKDF_Extract(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
                             kctx->key_len, key, keylen) != NULL;

     case EVP_PKEY_HKDEF_MODE_EXPAND_ONLY:
         return HKDF_Expand(kctx->md, kctx->key, kctx->key_len, kctx->info,
                            kctx->info_len, key, *keylen) != NULL;

     default:
         return 0;
     }
 }

 const EVP_PKEY_METHOD hkdf_pkey_meth = {
     EVP_PKEY_HKDF,
     0,
     pkey_hkdf_init,
     0,
     pkey_hkdf_cleanup,

     0, 0,
     0, 0,

     0,
     0,

     0,
     0,

     0, 0,

     0, 0, 0, 0,

     0, 0,

     0, 0,

     0,
     pkey_hkdf_derive,
     pkey_hkdf_ctrl,
     pkey_hkdf_ctrl_str
 };

 static unsigned char *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];
     unsigned char *ret;
     size_t prk_len;

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

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

     return ret;
 }

 static unsigned char *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)
 {
     unsigned int tmp_len;

     if (!HMAC(evp_md, salt, salt_len, key, key_len, prk, &tmp_len))
         return NULL;

     *prk_len = tmp_len;
     return prk;
 }

 static unsigned char *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;

     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 NULL;

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

     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;
     }

     HMAC_CTX_free(hmac);
     return okm;

  err:
     HMAC_CTX_free(hmac);
     return NULL;
 }
	/*
	* Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
	*
	* Licensed under the OpenSSL license (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 <string.h>
	#include <openssl/hmac.h>
	#include <openssl/kdf.h>
	#include <openssl/evp.h>
	#include "internal/cryptlib.h"
	#include "internal/evp_int.h"

	#define HKDF_MAXBUF 1024

	static unsigned char 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 unsigned char 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 unsigned char 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);

	typedef struct {
	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;
	} HKDF_PKEY_CTX;

	static int pkey_hkdf_init(EVP_PKEY_CTX *ctx)
	{
	HKDF_PKEY_CTX *kctx;

	kctx = OPENSSL_zalloc(sizeof(*kctx));
	if (kctx == NULL)
	return 0;

	ctx->data = kctx;

	return 1;
	}

	static void pkey_hkdf_cleanup(EVP_PKEY_CTX *ctx)
	{
	HKDF_PKEY_CTX *kctx = ctx->data;
	OPENSSL_clear_free(kctx->salt, kctx->salt_len);
	OPENSSL_clear_free(kctx->key, kctx->key_len);
	OPENSSL_cleanse(kctx->info, kctx->info_len);
	OPENSSL_free(kctx);
	}

	static int pkey_hkdf_ctrl(EVP_PKEY_CTX ctx, int type, int p1, void p2)
	{
	HKDF_PKEY_CTX *kctx = ctx->data;

	switch (type) {
	case EVP_PKEY_CTRL_HKDF_MD:
	if (p2 == NULL)
	return 0;

	kctx->md = p2;
	return 1;

	case EVP_PKEY_CTRL_HKDF_MODE:
	kctx->mode = p1;
	return 1;

	case EVP_PKEY_CTRL_HKDF_SALT:
	if (p1 == 0 \|\| p2 == NULL)
	return 1;

	if (p1 < 0)
	return 0;

	if (kctx->salt != NULL)
	OPENSSL_clear_free(kctx->salt, kctx->salt_len);

	kctx->salt = OPENSSL_memdup(p2, p1);
	if (kctx->salt == NULL)
	return 0;

	kctx->salt_len = p1;
	return 1;

	case EVP_PKEY_CTRL_HKDF_KEY:
	if (p1 < 0)
	return 0;

	if (kctx->key != NULL)
	OPENSSL_clear_free(kctx->key, kctx->key_len);

	kctx->key = OPENSSL_memdup(p2, p1);
	if (kctx->key == NULL)
	return 0;

	kctx->key_len = p1;
	return 1;

	case EVP_PKEY_CTRL_HKDF_INFO:
	if (p1 == 0 \|\| p2 == NULL)
	return 1;

	if (p1 < 0 \|\| p1 > (int)(HKDF_MAXBUF - kctx->info_len))
	return 0;

	memcpy(kctx->info + kctx->info_len, p2, p1);
	kctx->info_len += p1;
	return 1;

	default:
	return -2;

	}
	}

	static int pkey_hkdf_ctrl_str(EVP_PKEY_CTX ctx, const char type,
	const char *value)
	{
	if (strcmp(type, "mode") == 0) {
	int mode;

	if (strcmp(value, "EXTRACT_AND_EXPAND") == 0)
	mode = EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND;
	else if (strcmp(value, "EXTRACT_ONLY") == 0)
	mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
	else if (strcmp(value, "EXPAND_ONLY") == 0)
	mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
	else
	return 0;

	return EVP_PKEY_CTX_hkdf_mode(ctx, mode);
	}

	if (strcmp(type, "md") == 0)
	return EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_get_digestbyname(value));

	if (strcmp(type, "salt") == 0)
	return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);

	if (strcmp(type, "hexsalt") == 0)
	return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value);

	if (strcmp(type, "key") == 0)
	return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);

	if (strcmp(type, "hexkey") == 0)
	return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value);

	if (strcmp(type, "info") == 0)
	return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);

	if (strcmp(type, "hexinfo") == 0)
	return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value);

	return -2;
	}

	static int pkey_hkdf_derive(EVP_PKEY_CTX ctx, unsigned char key,
	size_t *keylen)
	{
	HKDF_PKEY_CTX *kctx = ctx->data;

	if (kctx->md == NULL \|\| kctx->key == NULL)
	return 0;

	switch (kctx->mode) {
	case EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND:
	return HKDF(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
	kctx->key_len, kctx->info, kctx->info_len, key,
	*keylen) != NULL;

	case EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY:
	if (key == NULL) {
	*keylen = EVP_MD_size(kctx->md);
	return 1;
	}
	return HKDF_Extract(kctx->md, kctx->salt, kctx->salt_len, kctx->key,
	kctx->key_len, key, keylen) != NULL;

	case EVP_PKEY_HKDEF_MODE_EXPAND_ONLY:
	return HKDF_Expand(kctx->md, kctx->key, kctx->key_len, kctx->info,
	kctx->info_len, key, *keylen) != NULL;

	default:
	return 0;
	}
	}

	const EVP_PKEY_METHOD hkdf_pkey_meth = {
	EVP_PKEY_HKDF,
	0,
	pkey_hkdf_init,
	0,
	pkey_hkdf_cleanup,

	0, 0,
	0, 0,

	0,
	0,

	0,
	0,

	0, 0,

	0, 0, 0, 0,

	0, 0,

	0, 0,

	0,
	pkey_hkdf_derive,
	pkey_hkdf_ctrl,
	pkey_hkdf_ctrl_str
	};

	static unsigned char 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];
	unsigned char *ret;
	size_t prk_len;

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

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

	return ret;
	}

	static unsigned char 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)
	{
	unsigned int tmp_len;

	if (!HMAC(evp_md, salt, salt_len, key, key_len, prk, &tmp_len))
	return NULL;

	*prk_len = tmp_len;
	return prk;
	}

	static unsigned char 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;

	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 NULL;

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

	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;
	}

	HMAC_CTX_free(hmac);
	return okm;

	err:
	HMAC_CTX_free(hmac);
	return NULL;
	}