/*

 * Copyright 2020-2021 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

 */

#include <string.h>

#include <openssl/crypto.h>

#include <openssl/core_dispatch.h>

#include <openssl/proverr.h>

#include "prov/implementations.h"

#include "prov/ciphercommon.h"

#include "prov/providercommon.h"

typedef struct prov_cipher_null_ctx_st {

    int enc;

    size_t tlsmacsize;

    const unsigned char *tlsmac;

} PROV_CIPHER_NULL_CTX;

static OSSL_FUNC_cipher_newctx_fn null_newctx;

static void *null_newctx(void *provctx)

{

    if (!ossl_prov_is_running())

        return NULL;

    return OPENSSL_zalloc(sizeof(PROV_CIPHER_NULL_CTX));

}

static OSSL_FUNC_cipher_freectx_fn null_freectx;

static void null_freectx(void *vctx)

{

    OPENSSL_free(vctx);

}

static OSSL_FUNC_cipher_encrypt_init_fn null_einit;

static int null_einit(void *vctx, const unsigned char *key, size_t keylen,

                      const unsigned char *iv, size_t ivlen,

                      const OSSL_PARAM params[])

{

    PROV_CIPHER_NULL_CTX *ctx = (PROV_CIPHER_NULL_CTX *)vctx;

    if (!ossl_prov_is_running())

        return 0;

    ctx->enc = 1;

    return 1;

}

static OSSL_FUNC_cipher_decrypt_init_fn null_dinit;

static int null_dinit(void *vctx, const unsigned char *key, size_t keylen,

                      const unsigned char *iv, size_t ivlen,

                      const OSSL_PARAM params[])

{

    if (!ossl_prov_is_running())

        return 0;

    return 1;

}

static OSSL_FUNC_cipher_cipher_fn null_cipher;

static int null_cipher(void *vctx, unsigned char *out, size_t *outl,

                       size_t outsize, const unsigned char *in, size_t inl)

{

    PROV_CIPHER_NULL_CTX *ctx = (PROV_CIPHER_NULL_CTX *)vctx;

    if (!ossl_prov_is_running())

        return 0;

    if (!ctx->enc && ctx->tlsmacsize > 0) {

        /*

         * TLS NULL cipher as per:

         * https://tools.ietf.org/html/rfc5246#section-6.2.3.1

         */

        if (inl < ctx->tlsmacsize)

            return 0;

        ctx->tlsmac = in + inl - ctx->tlsmacsize;

        inl -= ctx->tlsmacsize;

    }

    if (outsize < inl)

        return 0;

    if (in != out)

        memcpy(out, in, inl);

    *outl = inl;

    return 1;

}

static OSSL_FUNC_cipher_final_fn null_final;

static int null_final(void *vctx, unsigned char *out, size_t *outl,

                      size_t outsize)

{

    if (!ossl_prov_is_running())

        return 0;

    *outl = 0;

    return 1;

}

static OSSL_FUNC_cipher_get_params_fn null_get_params;

static int null_get_params(OSSL_PARAM params[])

{

    return ossl_cipher_generic_get_params(params, 0, 0, 0, 8, 0);

}

static const OSSL_PARAM null_known_gettable_ctx_params[] = {

    OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_KEYLEN, NULL),

    OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_IVLEN, NULL),

    { OSSL_CIPHER_PARAM_TLS_MAC, OSSL_PARAM_OCTET_PTR, NULL, 0, OSSL_PARAM_UNMODIFIED },

    OSSL_PARAM_END

};

static OSSL_FUNC_cipher_gettable_ctx_params_fn null_gettable_ctx_params;

static const OSSL_PARAM *null_gettable_ctx_params(ossl_unused void *cctx,

                                                  ossl_unused void *provctx)

{

    return null_known_gettable_ctx_params;

}

static OSSL_FUNC_cipher_get_ctx_params_fn null_get_ctx_params;

static int null_get_ctx_params(void *vctx, OSSL_PARAM params[])

{

    PROV_CIPHER_NULL_CTX *ctx = (PROV_CIPHER_NULL_CTX *)vctx;

    OSSL_PARAM *p;

    p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IVLEN);

    if (p != NULL && !OSSL_PARAM_set_size_t(p, 0)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);

        return 0;

    }

    p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_KEYLEN);

    if (p != NULL && !OSSL_PARAM_set_size_t(p, 0)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);

        return 0;

    }

    p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_TLS_MAC);

    if (p != NULL

        && !OSSL_PARAM_set_octet_ptr(p, ctx->tlsmac, ctx->tlsmacsize)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);

        return 0;

    }

    return 1;

}

static const OSSL_PARAM null_known_settable_ctx_params[] = {

    OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_TLS_MAC_SIZE, NULL),

    OSSL_PARAM_END

};

static OSSL_FUNC_cipher_settable_ctx_params_fn null_settable_ctx_params;

static const OSSL_PARAM *null_settable_ctx_params(ossl_unused void *cctx,

                                                  ossl_unused void *provctx)

{

    return null_known_settable_ctx_params;

}

static OSSL_FUNC_cipher_set_ctx_params_fn null_set_ctx_params;

static int null_set_ctx_params(void *vctx, const OSSL_PARAM params[])

{

    PROV_CIPHER_NULL_CTX *ctx = (PROV_CIPHER_NULL_CTX *)vctx;

    const OSSL_PARAM *p;

    p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_TLS_MAC_SIZE);

    if (p != NULL) {

        if (!OSSL_PARAM_get_size_t(p, &ctx->tlsmacsize)) {

            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);

            return 0;

        }

    }

    return 1;

}

const OSSL_DISPATCH ossl_null_functions[] = {

    { OSSL_FUNC_CIPHER_NEWCTX,

      (void (*)(void)) null_newctx },

    { OSSL_FUNC_CIPHER_FREECTX, (void (*)(void)) null_freectx },

    { OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void)) null_newctx },

    { OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))null_einit },

    { OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))null_dinit },

    { OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))null_cipher },

    { OSSL_FUNC_CIPHER_FINAL, (void (*)(void))null_final },

    { OSSL_FUNC_CIPHER_CIPHER, (void (*)(void))null_cipher },

    { OSSL_FUNC_CIPHER_GET_PARAMS, (void (*)(void)) null_get_params },

    { OSSL_FUNC_CIPHER_GETTABLE_PARAMS,

        (void (*)(void))ossl_cipher_generic_gettable_params },

    { OSSL_FUNC_CIPHER_GET_CTX_PARAMS, (void (*)(void))null_get_ctx_params },

    { OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS,

      (void (*)(void))null_gettable_ctx_params },

    { OSSL_FUNC_CIPHER_SET_CTX_PARAMS, (void (*)(void))null_set_ctx_params },

    { OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS,

      (void (*)(void))null_settable_ctx_params },

    { 0, NULL }

};