/*

 * Copyright 2019 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 <openssl/crypto.h>

#include <openssl/evp.h>

#include <openssl/err.h>

#include "internal/refcount.h"

#include "crypto/evp.h"

#include "internal/provider.h"

#include "internal/numbers.h"   /* includes SIZE_MAX */

#include "evp_local.h"

static EVP_KEYEXCH *evp_keyexch_new(OSSL_PROVIDER *prov)

{

    EVP_KEYEXCH *exchange = OPENSSL_zalloc(sizeof(EVP_KEYEXCH));

    if (exchange == NULL) {

        ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    exchange->lock = CRYPTO_THREAD_lock_new();

    if (exchange->lock == NULL) {

        ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);

        OPENSSL_free(exchange);

        return NULL;

    }

    exchange->prov = prov;

    ossl_provider_up_ref(prov);

    exchange->refcnt = 1;

    return exchange;

}

static void *evp_keyexch_from_dispatch(int name_id,

                                       const OSSL_DISPATCH *fns,

                                       OSSL_PROVIDER *prov)

{

    EVP_KEYEXCH *exchange = NULL;

    int fncnt = 0, paramfncnt = 0;

    if ((exchange = evp_keyexch_new(prov)) == NULL) {

        ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    exchange->name_id = name_id;

    for (; fns->function_id != 0; fns++) {

        switch (fns->function_id) {

        case OSSL_FUNC_KEYEXCH_NEWCTX:

            if (exchange->newctx != NULL)

                break;

            exchange->newctx = OSSL_get_OP_keyexch_newctx(fns);

            fncnt++;

            break;

        case OSSL_FUNC_KEYEXCH_INIT:

            if (exchange->init != NULL)

                break;

            exchange->init = OSSL_get_OP_keyexch_init(fns);

            fncnt++;

            break;

        case OSSL_FUNC_KEYEXCH_SET_PEER:

            if (exchange->set_peer != NULL)

                break;

            exchange->set_peer = OSSL_get_OP_keyexch_set_peer(fns);

            break;

        case OSSL_FUNC_KEYEXCH_DERIVE:

            if (exchange->derive != NULL)

                break;

            exchange->derive = OSSL_get_OP_keyexch_derive(fns);

            fncnt++;

            break;

        case OSSL_FUNC_KEYEXCH_FREECTX:

            if (exchange->freectx != NULL)

                break;

            exchange->freectx = OSSL_get_OP_keyexch_freectx(fns);

            fncnt++;

            break;

        case OSSL_FUNC_KEYEXCH_DUPCTX:

            if (exchange->dupctx != NULL)

                break;

            exchange->dupctx = OSSL_get_OP_keyexch_dupctx(fns);

            break;

        case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:

            if (exchange->set_ctx_params != NULL)

                break;

            exchange->set_ctx_params = OSSL_get_OP_keyexch_set_ctx_params(fns);

            paramfncnt++;

            break;

        case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:

            if (exchange->settable_ctx_params != NULL)

                break;

            exchange->settable_ctx_params

                = OSSL_get_OP_keyexch_settable_ctx_params(fns);

            paramfncnt++;

            break;

        }

    }

    if (fncnt != 4 || (paramfncnt != 0 && paramfncnt != 2)) {

        /*

         * In order to be a consistent set of functions we must have at least

         * a complete set of "exchange" functions: init, derive, newctx,

         * and freectx. The set_ctx_params and settable_ctx_params functions are

         * optional, but if one of them is present then the other one must also

         * be present. The dupctx and set_peer functions are optional.

         */

        EVPerr(EVP_F_EVP_KEYEXCH_FROM_DISPATCH,

               EVP_R_INVALID_PROVIDER_FUNCTIONS);

        goto err;

    }

    return exchange;

 err:

    EVP_KEYEXCH_free(exchange);

    return NULL;

}

void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)

{

    if (exchange != NULL) {

        int i;

        CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);

        if (i > 0)

            return;

        ossl_provider_free(exchange->prov);

        CRYPTO_THREAD_lock_free(exchange->lock);

        OPENSSL_free(exchange);

    }

}

int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)

{

    int ref = 0;

    CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);

    return 1;

}

OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)

{

    return exchange->prov;

}

EVP_KEYEXCH *EVP_KEYEXCH_fetch(OPENSSL_CTX *ctx, const char *algorithm,

                               const char *properties)

{

    return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,

                             evp_keyexch_from_dispatch,

                             (int (*)(void *))EVP_KEYEXCH_up_ref,

                             (void (*)(void *))EVP_KEYEXCH_free);

}

int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)

{

    int ret;

    void *provkey = NULL;

    EVP_KEYEXCH *exchange = NULL;

    EVP_KEYMGMT *tmp_keymgmt = NULL;

    const char *supported_exch = NULL;

    if (ctx == NULL) {

        EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    evp_pkey_ctx_free_old_ops(ctx);

    ctx->operation = EVP_PKEY_OP_DERIVE;

    /*

     * TODO when we stop falling back to legacy, this and the ERR_pop_to_mark()

     * calls can be removed.

     */

    ERR_set_mark();

    if (ctx->engine != NULL || ctx->keytype == NULL)

        goto legacy;

    /* Ensure that the key is provided.  If not, go legacy */

    tmp_keymgmt = ctx->keymgmt;

    provkey = evp_pkey_make_provided(ctx->pkey, ctx->libctx,

                                     &tmp_keymgmt, ctx->propquery);

    if (provkey == NULL)

        goto legacy;

    if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {

        ERR_clear_last_mark();

        ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

        goto err;

    }

    EVP_KEYMGMT_free(ctx->keymgmt);

    ctx->keymgmt = tmp_keymgmt;

    if (ctx->keymgmt->query_operation_name != NULL)

        supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);

    /*

     * If we didn't get a supported exch, assume there is one with the

     * same name as the key type.

     */

    if (supported_exch == NULL)

        supported_exch = ctx->keytype;

    /*

     * Because we cleared out old ops, we shouldn't need to worry about

     * checking if exchange is already there.

     */

    exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);

    if (exchange == NULL

        || (EVP_KEYMGMT_provider(ctx->keymgmt)

            != EVP_KEYEXCH_provider(exchange))) {

        /*

         * We don't need to free ctx->keymgmt here, as it's not necessarily

         * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().

         */

        EVP_KEYEXCH_free(exchange);

        goto legacy;

    }

    /*

     * TODO remove this when legacy is gone

     * If we don't have the full support we need with provided methods,

     * let's go see if legacy does.

     */

    ERR_pop_to_mark();

    /* No more legacy from here down to legacy: */

    ctx->op.kex.exchange = exchange;

    ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));

    if (ctx->op.kex.exchprovctx == NULL) {

        /* The provider key can stay in the cache */

        EVPerr(0, EVP_R_INITIALIZATION_ERROR);

        goto err;

    }

    ret = exchange->init(ctx->op.kex.exchprovctx, provkey);

    return ret ? 1 : 0;

 err:

    ctx->operation = EVP_PKEY_OP_UNDEFINED;

    return 0;

 legacy:

    /*

     * TODO remove this when legacy is gone

     * If we don't have the full support we need with provided methods,

     * let's go see if legacy does.

     */

    ERR_pop_to_mark();

#ifdef FIPS_MODE

    return 0;

#else

    if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {

        EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    if (ctx->pmeth->derive_init == NULL)

        return 1;

    ret = ctx->pmeth->derive_init(ctx);

    if (ret <= 0)

        ctx->operation = EVP_PKEY_OP_UNDEFINED;

    return ret;

#endif

}

int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)

{

    int ret = 0;

    void *provkey = NULL;

    if (ctx == NULL) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,

               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)

        goto legacy;

    if (ctx->op.kex.exchange->set_peer == NULL) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,

               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    provkey = evp_keymgmt_util_export_to_provider(peer, ctx->keymgmt);

    /* If export failed, legacy may be able to pick it up */

    if (provkey == NULL)

        goto legacy;

    return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);

 legacy:

#ifdef FIPS_MODE

    return ret;

#else

    if (ctx->pmeth == NULL

        || !(ctx->pmeth->derive != NULL

             || ctx->pmeth->encrypt != NULL

             || ctx->pmeth->decrypt != NULL)

        || ctx->pmeth->ctrl == NULL) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,

               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    if (ctx->operation != EVP_PKEY_OP_DERIVE

        && ctx->operation != EVP_PKEY_OP_ENCRYPT

        && ctx->operation != EVP_PKEY_OP_DECRYPT) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,

               EVP_R_OPERATON_NOT_INITIALIZED);

        return -1;

    }

    ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);

    if (ret <= 0)

        return ret;

    if (ret == 2)

        return 1;

    if (ctx->pkey == NULL) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);

        return -1;

    }

    if (ctx->pkey->type != peer->type) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);

        return -1;

    }

    /*

     * For clarity.  The error is if parameters in peer are

     * present (!missing) but don't match.  EVP_PKEY_cmp_parameters may return

     * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1

     * (different key types) is impossible here because it is checked earlier.

     * -2 is OK for us here, as well as 1, so we can check for 0 only.

     */

    if (!EVP_PKEY_missing_parameters(peer) &&

        !EVP_PKEY_cmp_parameters(ctx->pkey, peer)) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);

        return -1;

    }

    EVP_PKEY_free(ctx->peerkey);

    ctx->peerkey = peer;

    ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);

    if (ret <= 0) {

        ctx->peerkey = NULL;

        return ret;

    }

    EVP_PKEY_up_ref(peer);

    return 1;

#endif

}

int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)

{

    int ret;

    if (ctx == NULL) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE,

               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);

        return -1;

    }

    if (ctx->op.kex.exchprovctx == NULL)

        goto legacy;

    ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,

                                       SIZE_MAX);

    return ret;

 legacy:

    if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {

        EVPerr(EVP_F_EVP_PKEY_DERIVE,

               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return -2;

    }

    M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)

        return ctx->pmeth->derive(ctx, key, pkeylen);

}

int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)

{

    return keyexch->name_id;

}

int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)

{

    return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);

}

void EVP_KEYEXCH_do_all_provided(OPENSSL_CTX *libctx,

                                 void (*fn)(EVP_KEYEXCH *keyexch, void *arg),

                                 void *arg)

{

    evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,

                       (void (*)(void *, void *))fn, arg,

                       evp_keyexch_from_dispatch,

                       (void (*)(void *))EVP_KEYEXCH_free);

}

void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,

                              void (*fn)(const char *name, void *data),

                              void *data)

{

    if (keyexch->prov != NULL)

        evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);

}