/*

 * Copyright 2018-2023 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 "internal/ssl3_cbc.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;

};

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;

    memset(&dst->digest, 0, sizeof(dst->digest));

    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->key != NULL)

        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)

        return hmac_setkey(macctx, key, keylen);

    /* Just reinit the HMAC context */

    return HMAC_Init_ex(macctx->ctx, NULL, 0, NULL, NULL);

}

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 (!hmac_setkey(macctx, p->data, p->data_size))

            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 },

    OSSL_DISPATCH_END

};