/*

 * Copyright 2007-2018 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 <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/x509.h>

#include <openssl/x509v3.h>

#include <openssl/evp.h>

#include <openssl/hmac.h>

#include <openssl/err.h>

#include "internal/evp_int.h"

/* HMAC pkey context structure */

typedef struct {

    const EVP_MD *md;           /* MD for HMAC use */

    ASN1_OCTET_STRING ktmp;     /* Temp storage for key */

    HMAC_CTX *ctx;

} HMAC_PKEY_CTX;

static int pkey_hmac_init(EVP_PKEY_CTX *ctx)

{

    HMAC_PKEY_CTX *hctx;

    if ((hctx = OPENSSL_zalloc(sizeof(*hctx))) == NULL) {

        CRYPTOerr(CRYPTO_F_PKEY_HMAC_INIT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    hctx->ktmp.type = V_ASN1_OCTET_STRING;

    hctx->ctx = HMAC_CTX_new();

    if (hctx->ctx == NULL) {

        OPENSSL_free(hctx);

        return 0;

    }

    ctx->data = hctx;

    ctx->keygen_info_count = 0;

    return 1;

}

static void pkey_hmac_cleanup(EVP_PKEY_CTX *ctx);

static int pkey_hmac_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)

{

    HMAC_PKEY_CTX *sctx, *dctx;

    /* allocate memory for dst->data and a new HMAC_CTX in dst->data->ctx */

    if (!pkey_hmac_init(dst))

        return 0;

    sctx = EVP_PKEY_CTX_get_data(src);

    dctx = EVP_PKEY_CTX_get_data(dst);

    dctx->md = sctx->md;

    if (!HMAC_CTX_copy(dctx->ctx, sctx->ctx))

        goto err;

    if (sctx->ktmp.data) {

        if (!ASN1_OCTET_STRING_set(&dctx->ktmp,

                                   sctx->ktmp.data, sctx->ktmp.length))

            goto err;

    }

    return 1;

err:

    /* release HMAC_CTX in dst->data->ctx and memory allocated for dst->data */

    pkey_hmac_cleanup (dst);

    return 0;

}

static void pkey_hmac_cleanup(EVP_PKEY_CTX *ctx)

{

    HMAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);

    if (hctx != NULL) {

        HMAC_CTX_free(hctx->ctx);

        OPENSSL_clear_free(hctx->ktmp.data, hctx->ktmp.length);

        OPENSSL_free(hctx);

        EVP_PKEY_CTX_set_data(ctx, NULL);

    }

}

static int pkey_hmac_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

{

    ASN1_OCTET_STRING *hkey = NULL;

    HMAC_PKEY_CTX *hctx = ctx->data;

    if (!hctx->ktmp.data)

        return 0;

    hkey = ASN1_OCTET_STRING_dup(&hctx->ktmp);

    if (!hkey)

        return 0;

    EVP_PKEY_assign(pkey, EVP_PKEY_HMAC, hkey);

    return 1;

}

static int int_update(EVP_MD_CTX *ctx, const void *data, size_t count)

{

    HMAC_PKEY_CTX *hctx = EVP_MD_CTX_pkey_ctx(ctx)->data;

    if (!HMAC_Update(hctx->ctx, data, count))

        return 0;

    return 1;

}

static int hmac_signctx_init(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)

{

    HMAC_PKEY_CTX *hctx = ctx->data;

    HMAC_CTX_set_flags(hctx->ctx,

                       EVP_MD_CTX_test_flags(mctx, ~EVP_MD_CTX_FLAG_NO_INIT));

    EVP_MD_CTX_set_flags(mctx, EVP_MD_CTX_FLAG_NO_INIT);

    EVP_MD_CTX_set_update_fn(mctx, int_update);

    return 1;

}

static int hmac_signctx(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,

                        EVP_MD_CTX *mctx)

{

    unsigned int hlen;

    HMAC_PKEY_CTX *hctx = ctx->data;

    int l = EVP_MD_CTX_size(mctx);

    if (l < 0)

        return 0;

    *siglen = l;

    if (!sig)

        return 1;

    if (!HMAC_Final(hctx->ctx, sig, &hlen))

        return 0;

    *siglen = (size_t)hlen;

    return 1;

}

static int pkey_hmac_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)

{

    HMAC_PKEY_CTX *hctx = ctx->data;

    ASN1_OCTET_STRING *key;

    switch (type) {

    case EVP_PKEY_CTRL_SET_MAC_KEY:

        if ((!p2 && p1 > 0) || (p1 < -1))

            return 0;

        if (!ASN1_OCTET_STRING_set(&hctx->ktmp, p2, p1))

            return 0;

        break;

    case EVP_PKEY_CTRL_MD:

        hctx->md = p2;

        break;

    case EVP_PKEY_CTRL_DIGESTINIT:

        key = (ASN1_OCTET_STRING *)ctx->pkey->pkey.ptr;

        if (!HMAC_Init_ex(hctx->ctx, key->data, key->length, hctx->md,

                          ctx->engine))

            return 0;

        break;

    default:

        return -2;

    }

    return 1;

}

static int pkey_hmac_ctrl_str(EVP_PKEY_CTX *ctx,

                              const char *type, const char *value)

{

    if (!value) {

        return 0;

    }

    if (strcmp(type, "key") == 0)

        return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_SET_MAC_KEY, value);

    if (strcmp(type, "hexkey") == 0)

        return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_SET_MAC_KEY, value);

    return -2;

}

const EVP_PKEY_METHOD hmac_pkey_meth = {

    EVP_PKEY_HMAC,

    0,

    pkey_hmac_init,

    pkey_hmac_copy,

    pkey_hmac_cleanup,

    0, 0,

    0,

    pkey_hmac_keygen,

    0, 0,

    0, 0,

    0, 0,

    hmac_signctx_init,

    hmac_signctx,

    0, 0,

    0, 0,

    0, 0,

    0, 0,

    pkey_hmac_ctrl,

    pkey_hmac_ctrl_str

};