providers/implementations/macs/hmac_prov.c - third_party/openssl - Git at Google

 /*
  * Copyright 2018-2021 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
  */

 /*
  * HMAC low level APIs are deprecated for public use, but still ok for internal
  * use.
  */
 #include "internal/deprecated.h"

 #include <string.h>

 #include <openssl/core_dispatch.h>
 #include <openssl/core_names.h>
 #include <openssl/params.h>
 #include <openssl/evp.h>
 #include <openssl/hmac.h>

 #include "prov/implementations.h"
 #include "prov/provider_ctx.h"
 #include "prov/provider_util.h"
 #include "prov/providercommon.h"

 /*
  * Forward declaration of everything implemented here.  This is not strictly
  * necessary for the compiler, but provides an assurance that the signatures
  * of the functions in the dispatch table are correct.
  */
 static OSSL_FUNC_mac_newctx_fn hmac_new;
 static OSSL_FUNC_mac_dupctx_fn hmac_dup;
 static OSSL_FUNC_mac_freectx_fn hmac_free;
 static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
 static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
 static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
 static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
 static OSSL_FUNC_mac_init_fn hmac_init;
 static OSSL_FUNC_mac_update_fn hmac_update;
 static OSSL_FUNC_mac_final_fn hmac_final;

 /* local HMAC context structure */

 /* typedef EVP_MAC_IMPL */
 struct hmac_data_st {
     void *provctx;
     HMAC_CTX *ctx;               /* HMAC context */
     PROV_DIGEST digest;
     unsigned char *key;
     size_t keylen;
     /* Length of full TLS record including the MAC and any padding */
     size_t tls_data_size;
     unsigned char tls_header[13];
     int tls_header_set;
     unsigned char tls_mac_out[EVP_MAX_MD_SIZE];
     size_t tls_mac_out_size;
 };

 /* Defined in ssl/s3_cbc.c */
 int ssl3_cbc_digest_record(const EVP_MD *md,
                            unsigned char *md_out,
                            size_t *md_out_size,
                            const unsigned char header[13],
                            const unsigned char *data,
                            size_t data_size,
                            size_t data_plus_mac_plus_padding_size,
                            const unsigned char *mac_secret,
                            size_t mac_secret_length, char is_sslv3);

 static void *hmac_new(void *provctx)
 {
     struct hmac_data_st *macctx;

     if (!ossl_prov_is_running())
         return NULL;

     if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
         || (macctx->ctx = HMAC_CTX_new()) == NULL) {
         OPENSSL_free(macctx);
         return NULL;
     }
     macctx->provctx = provctx;

     return macctx;
 }

 static void hmac_free(void *vmacctx)
 {
     struct hmac_data_st *macctx = vmacctx;

     if (macctx != NULL) {
         HMAC_CTX_free(macctx->ctx);
         ossl_prov_digest_reset(&macctx->digest);
         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
         OPENSSL_free(macctx);
     }
 }

 static void *hmac_dup(void *vsrc)
 {
     struct hmac_data_st *src = vsrc;
     struct hmac_data_st *dst;
     HMAC_CTX *ctx;

     if (!ossl_prov_is_running())
         return NULL;
     dst = hmac_new(src->provctx);
     if (dst == NULL)
         return NULL;

     ctx = dst->ctx;
     *dst = *src;
     dst->ctx = ctx;
     dst->key = NULL;

     if (!HMAC_CTX_copy(dst->ctx, src->ctx)
         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
         hmac_free(dst);
         return NULL;
     }
     if (src->key != NULL) {
         /* There is no "secure" OPENSSL_memdup */
         dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
         if (dst->key == NULL) {
             hmac_free(dst);
             return 0;
         }
         memcpy(dst->key, src->key, src->keylen);
     }
     return dst;
 }

 static size_t hmac_size(struct hmac_data_st *macctx)
 {
     return HMAC_size(macctx->ctx);
 }

 static int hmac_block_size(struct hmac_data_st *macctx)
 {
     const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);

     if (md == NULL)
         return 0;
     return EVP_MD_block_size(md);
 }

 static int hmac_setkey(struct hmac_data_st *macctx,
                        const unsigned char *key, size_t keylen)
 {
     const EVP_MD *digest;

     if (macctx->keylen > 0)
         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
     /* Keep a copy of the key in case we need it for TLS HMAC */
     macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
     if (macctx->key == NULL)
         return 0;
     memcpy(macctx->key, key, keylen);
     macctx->keylen = keylen;

     digest = ossl_prov_digest_md(&macctx->digest);
     /* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
     if (key != NULL || (macctx->tls_data_size == 0 && digest != NULL))
         return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
                             ossl_prov_digest_engine(&macctx->digest));
     return 1;
 }

 static int hmac_init(void *vmacctx, const unsigned char *key,
                      size_t keylen, const OSSL_PARAM params[])
 {
     struct hmac_data_st *macctx = vmacctx;

     if (!ossl_prov_is_running() || !hmac_set_ctx_params(macctx, params))
         return 0;

     if (key != NULL && !hmac_setkey(macctx, key, keylen))
         return 0;
     return 1;
 }

 static int hmac_update(void *vmacctx, const unsigned char *data,
                        size_t datalen)
 {
     struct hmac_data_st *macctx = vmacctx;

     if (macctx->tls_data_size > 0) {
         /* We're doing a TLS HMAC */
         if (!macctx->tls_header_set) {
             /* We expect the first update call to contain the TLS header */
             if (datalen != sizeof(macctx->tls_header))
                 return 0;
             memcpy(macctx->tls_header, data, datalen);
             macctx->tls_header_set = 1;
             return 1;
         }
         /* macctx->tls_data_size is datalen plus the padding length */
         if (macctx->tls_data_size < datalen)
             return 0;

         return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
                                       macctx->tls_mac_out,
                                       &macctx->tls_mac_out_size,
                                       macctx->tls_header,
                                       data,
                                       datalen,
                                       macctx->tls_data_size,
                                       macctx->key,
                                       macctx->keylen,
                                       0);
     }

     return HMAC_Update(macctx->ctx, data, datalen);
 }

 static int hmac_final(void *vmacctx, unsigned char *out, size_t *outl,
                       size_t outsize)
 {
     unsigned int hlen;
     struct hmac_data_st *macctx = vmacctx;

     if (!ossl_prov_is_running())
         return 0;
     if (macctx->tls_data_size > 0) {
         if (macctx->tls_mac_out_size == 0)
             return 0;
         if (outl != NULL)
             *outl = macctx->tls_mac_out_size;
         memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
         return 1;
     }
     if (!HMAC_Final(macctx->ctx, out, &hlen))
         return 0;
     *outl = hlen;
     return 1;
 }

 static const OSSL_PARAM known_gettable_ctx_params[] = {
     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
     OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
     OSSL_PARAM_END
 };
 static const OSSL_PARAM *hmac_gettable_ctx_params(ossl_unused void *ctx,
                                                   ossl_unused void *provctx)
 {
     return known_gettable_ctx_params;
 }

 static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
 {
     struct hmac_data_st *macctx = vmacctx;
     OSSL_PARAM *p;

     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
             && !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
         return 0;

     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
             && !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
         return 0;

     return 1;
 }

 static const OSSL_PARAM known_settable_ctx_params[] = {
     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
     OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
     OSSL_PARAM_END
 };
 static const OSSL_PARAM *hmac_settable_ctx_params(ossl_unused void *ctx,
                                                   ossl_unused void *provctx)
 {
     return known_settable_ctx_params;
 }

 static int set_flag(const OSSL_PARAM params[], const char *key, int mask,
                     int *flags)
 {
     const OSSL_PARAM *p = OSSL_PARAM_locate_const(params, key);
     int flag = 0;

     if (p != NULL) {
         if (!OSSL_PARAM_get_int(p, &flag))
             return 0;
         if (flag == 0)
             *flags &= ~mask;
         else
             *flags |= mask;
     }
     return 1;
 }

 /*
  * ALL parameters should be set before init().
  */
 static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
 {
     struct hmac_data_st *macctx = vmacctx;
     OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
     const OSSL_PARAM *p;
     int flags = 0;

     if (params == NULL)
         return 1;

     if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
         return 0;

     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_NOINIT, EVP_MD_CTX_FLAG_NO_INIT,
                   &flags))
         return 0;
     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_ONESHOT, EVP_MD_CTX_FLAG_ONESHOT,
                   &flags))
         return 0;
     if (flags)
         HMAC_CTX_set_flags(macctx->ctx, flags);

     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
         if (p->data_type != OSSL_PARAM_OCTET_STRING)
             return 0;

         if (macctx->keylen > 0)
             OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
         /* Keep a copy of the key if we need it for TLS HMAC */
         macctx->key = OPENSSL_secure_malloc(p->data_size > 0 ? p->data_size : 1);
         if (macctx->key == NULL)
             return 0;
         memcpy(macctx->key, p->data, p->data_size);
         macctx->keylen = p->data_size;

         if (!HMAC_Init_ex(macctx->ctx, p->data, p->data_size,
                           ossl_prov_digest_md(&macctx->digest),
                           NULL /* ENGINE */))
             return 0;

     }
     if ((p = OSSL_PARAM_locate_const(params,
                                      OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
         if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
             return 0;
     }
     return 1;
 }

 const OSSL_DISPATCH ossl_hmac_functions[] = {
     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
     { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
     { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
       (void (*)(void))hmac_gettable_ctx_params },
     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
       (void (*)(void))hmac_settable_ctx_params },
     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
     { 0, NULL }
 };
	/*
	* Copyright 2018-2021 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
	*/

	/*
	* HMAC low level APIs are deprecated for public use, but still ok for internal
	* use.
	*/
	#include "internal/deprecated.h"

	#include <string.h>

	#include <openssl/core_dispatch.h>
	#include <openssl/core_names.h>
	#include <openssl/params.h>
	#include <openssl/evp.h>
	#include <openssl/hmac.h>

	#include "prov/implementations.h"
	#include "prov/provider_ctx.h"
	#include "prov/provider_util.h"
	#include "prov/providercommon.h"

	/*
	* Forward declaration of everything implemented here. This is not strictly
	* necessary for the compiler, but provides an assurance that the signatures
	* of the functions in the dispatch table are correct.
	*/
	static OSSL_FUNC_mac_newctx_fn hmac_new;
	static OSSL_FUNC_mac_dupctx_fn hmac_dup;
	static OSSL_FUNC_mac_freectx_fn hmac_free;
	static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
	static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
	static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
	static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
	static OSSL_FUNC_mac_init_fn hmac_init;
	static OSSL_FUNC_mac_update_fn hmac_update;
	static OSSL_FUNC_mac_final_fn hmac_final;

	/* local HMAC context structure */

	/* typedef EVP_MAC_IMPL */
	struct hmac_data_st {
	void *provctx;
	HMAC_CTX ctx; / HMAC context */
	PROV_DIGEST digest;
	unsigned char *key;
	size_t keylen;
	/* Length of full TLS record including the MAC and any padding */
	size_t tls_data_size;
	unsigned char tls_header[13];
	int tls_header_set;
	unsigned char tls_mac_out[EVP_MAX_MD_SIZE];
	size_t tls_mac_out_size;
	};

	/* Defined in ssl/s3_cbc.c */
	int ssl3_cbc_digest_record(const EVP_MD *md,
	unsigned char *md_out,
	size_t *md_out_size,
	const unsigned char header[13],
	const unsigned char *data,
	size_t data_size,
	size_t data_plus_mac_plus_padding_size,
	const unsigned char *mac_secret,
	size_t mac_secret_length, char is_sslv3);

	static void hmac_new(void provctx)
	{
	struct hmac_data_st *macctx;

	if (!ossl_prov_is_running())
	return NULL;

	if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
	\|\| (macctx->ctx = HMAC_CTX_new()) == NULL) {
	OPENSSL_free(macctx);
	return NULL;
	}
	macctx->provctx = provctx;

	return macctx;
	}

	static void hmac_free(void *vmacctx)
	{
	struct hmac_data_st *macctx = vmacctx;

	if (macctx != NULL) {
	HMAC_CTX_free(macctx->ctx);
	ossl_prov_digest_reset(&macctx->digest);
	OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
	OPENSSL_free(macctx);
	}
	}

	static void hmac_dup(void vsrc)
	{
	struct hmac_data_st *src = vsrc;
	struct hmac_data_st *dst;
	HMAC_CTX *ctx;

	if (!ossl_prov_is_running())
	return NULL;
	dst = hmac_new(src->provctx);
	if (dst == NULL)
	return NULL;

	ctx = dst->ctx;
	dst = src;
	dst->ctx = ctx;
	dst->key = NULL;

	if (!HMAC_CTX_copy(dst->ctx, src->ctx)
	\|\| !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
	hmac_free(dst);
	return NULL;
	}
	if (src->key != NULL) {
	/* There is no "secure" OPENSSL_memdup */
	dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
	if (dst->key == NULL) {
	hmac_free(dst);
	return 0;
	}
	memcpy(dst->key, src->key, src->keylen);
	}
	return dst;
	}

	static size_t hmac_size(struct hmac_data_st *macctx)
	{
	return HMAC_size(macctx->ctx);
	}

	static int hmac_block_size(struct hmac_data_st *macctx)
	{
	const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);

	if (md == NULL)
	return 0;
	return EVP_MD_block_size(md);
	}

	static int hmac_setkey(struct hmac_data_st *macctx,
	const unsigned char *key, size_t keylen)
	{
	const EVP_MD *digest;

	if (macctx->keylen > 0)
	OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
	/* Keep a copy of the key in case we need it for TLS HMAC */
	macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
	if (macctx->key == NULL)
	return 0;
	memcpy(macctx->key, key, keylen);
	macctx->keylen = keylen;

	digest = ossl_prov_digest_md(&macctx->digest);
	/* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
	if (key != NULL \|\| (macctx->tls_data_size == 0 && digest != NULL))
	return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
	ossl_prov_digest_engine(&macctx->digest));
	return 1;
	}

	static int hmac_init(void vmacctx, const unsigned char key,
	size_t keylen, const OSSL_PARAM params[])
	{
	struct hmac_data_st *macctx = vmacctx;

	if (!ossl_prov_is_running() \|\| !hmac_set_ctx_params(macctx, params))
	return 0;

	if (key != NULL && !hmac_setkey(macctx, key, keylen))
	return 0;
	return 1;
	}

	static int hmac_update(void vmacctx, const unsigned char data,
	size_t datalen)
	{
	struct hmac_data_st *macctx = vmacctx;

	if (macctx->tls_data_size > 0) {
	/* We're doing a TLS HMAC */
	if (!macctx->tls_header_set) {
	/* We expect the first update call to contain the TLS header */
	if (datalen != sizeof(macctx->tls_header))
	return 0;
	memcpy(macctx->tls_header, data, datalen);
	macctx->tls_header_set = 1;
	return 1;
	}
	/* macctx->tls_data_size is datalen plus the padding length */
	if (macctx->tls_data_size < datalen)
	return 0;

	return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
	macctx->tls_mac_out,
	&macctx->tls_mac_out_size,
	macctx->tls_header,
	data,
	datalen,
	macctx->tls_data_size,
	macctx->key,
	macctx->keylen,
	0);
	}

	return HMAC_Update(macctx->ctx, data, datalen);
	}

	static int hmac_final(void vmacctx, unsigned char out, size_t *outl,
	size_t outsize)
	{
	unsigned int hlen;
	struct hmac_data_st *macctx = vmacctx;

	if (!ossl_prov_is_running())
	return 0;
	if (macctx->tls_data_size > 0) {
	if (macctx->tls_mac_out_size == 0)
	return 0;
	if (outl != NULL)
	*outl = macctx->tls_mac_out_size;
	memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
	return 1;
	}
	if (!HMAC_Final(macctx->ctx, out, &hlen))
	return 0;
	*outl = hlen;
	return 1;
	}

	static const OSSL_PARAM known_gettable_ctx_params[] = {
	OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
	OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
	OSSL_PARAM_END
	};
	static const OSSL_PARAM hmac_gettable_ctx_params(ossl_unused void ctx,
	ossl_unused void *provctx)
	{
	return known_gettable_ctx_params;
	}

	static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
	{
	struct hmac_data_st *macctx = vmacctx;
	OSSL_PARAM *p;

	if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
	&& !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
	return 0;

	if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
	&& !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
	return 0;

	return 1;
	}

	static const OSSL_PARAM known_settable_ctx_params[] = {
	OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
	OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
	OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
	OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
	OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
	OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
	OSSL_PARAM_END
	};
	static const OSSL_PARAM hmac_settable_ctx_params(ossl_unused void ctx,
	ossl_unused void *provctx)
	{
	return known_settable_ctx_params;
	}

	static int set_flag(const OSSL_PARAM params[], const char *key, int mask,
	int *flags)
	{
	const OSSL_PARAM *p = OSSL_PARAM_locate_const(params, key);
	int flag = 0;

	if (p != NULL) {
	if (!OSSL_PARAM_get_int(p, &flag))
	return 0;
	if (flag == 0)
	*flags &= ~mask;
	else
	*flags \|= mask;
	}
	return 1;
	}

	/*
	* ALL parameters should be set before init().
	*/
	static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
	{
	struct hmac_data_st *macctx = vmacctx;
	OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
	const OSSL_PARAM *p;
	int flags = 0;

	if (params == NULL)
	return 1;

	if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
	return 0;

	if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_NOINIT, EVP_MD_CTX_FLAG_NO_INIT,
	&flags))
	return 0;
	if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_ONESHOT, EVP_MD_CTX_FLAG_ONESHOT,
	&flags))
	return 0;
	if (flags)
	HMAC_CTX_set_flags(macctx->ctx, flags);

	if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
	if (p->data_type != OSSL_PARAM_OCTET_STRING)
	return 0;

	if (macctx->keylen > 0)
	OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
	/* Keep a copy of the key if we need it for TLS HMAC */
	macctx->key = OPENSSL_secure_malloc(p->data_size > 0 ? p->data_size : 1);
	if (macctx->key == NULL)
	return 0;
	memcpy(macctx->key, p->data, p->data_size);
	macctx->keylen = p->data_size;

	if (!HMAC_Init_ex(macctx->ctx, p->data, p->data_size,
	ossl_prov_digest_md(&macctx->digest),
	NULL /* ENGINE */))
	return 0;

	}
	if ((p = OSSL_PARAM_locate_const(params,
	OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
	if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
	return 0;
	}
	return 1;
	}

	const OSSL_DISPATCH ossl_hmac_functions[] = {
	{ OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
	{ OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
	{ OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
	{ OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
	{ OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
	{ OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
	{ OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
	(void (*)(void))hmac_gettable_ctx_params },
	{ OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
	{ OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
	(void (*)(void))hmac_settable_ctx_params },
	{ OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
	{ 0, NULL }
	};