/*

 * Copyright 2019-2024 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright (c) 2019, Oracle and/or its affiliates.  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/ebcdic.h>

#include <openssl/err.h>

#include <openssl/params.h>

/*

 * When processing text to params, we're trying to be smart with numbers.

 * Instead of handling each specific separate integer type, we use a bignum

 * and ensure that it isn't larger than the expected size, and we then make

 * sure it is the expected size...  if there is one given.

 * (if the size can be arbitrary, then we give whatever we have)

 */

static int prepare_from_text(const OSSL_PARAM *paramdefs, const char *key,

                             const char *value, size_t value_n,

                             /* Output parameters */

                             const OSSL_PARAM **paramdef, int *ishex,

                             size_t *buf_n, BIGNUM **tmpbn, int *found)

{

    const OSSL_PARAM *p;

    size_t buf_bits;

    int r;

    /*

     * ishex is used to translate legacy style string controls in hex format

     * to octet string parameters.

     */

    *ishex = strncmp(key, "hex", 3) == 0;

    if (*ishex)

        key += 3;

    p = *paramdef = OSSL_PARAM_locate_const(paramdefs, key);

    if (found != NULL)

        *found = p != NULL;

    if (p == NULL)

        return 0;

    switch (p->data_type) {

    case OSSL_PARAM_INTEGER:

    case OSSL_PARAM_UNSIGNED_INTEGER:

        if (*ishex)

            r = BN_hex2bn(tmpbn, value);

        else

            r = BN_asc2bn(tmpbn, value);

        if (r == 0 || *tmpbn == NULL)

            return 0;

        if (p->data_type == OSSL_PARAM_UNSIGNED_INTEGER

            && BN_is_negative(*tmpbn)) {

            ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_INVALID_NEGATIVE_VALUE);

            return 0;

        }

        /*

         * 2's complement negate, part 1

         *

         * BN_bn2nativepad puts the absolute value of the number in the

         * buffer, i.e. if it's negative, we need to deal with it.  We do

         * it by subtracting 1 here and inverting the bytes in

         * construct_from_text() below.

         * To subtract 1 from an absolute value of a negative number we

         * actually have to add 1: -3 - 1 = -4, |-3| = 3 + 1 = 4.

         */

        if (p->data_type == OSSL_PARAM_INTEGER && BN_is_negative(*tmpbn)

            && !BN_add_word(*tmpbn, 1)) {

            return 0;

        }

        buf_bits = (size_t)BN_num_bits(*tmpbn);

        /*

         * Compensate for cases where the most significant bit in

         * the resulting OSSL_PARAM buffer will be set after the

         * BN_bn2nativepad() call, as the implied sign may not be

         * correct after the second part of the 2's complement

         * negation has been performed.

         * We fix these cases by extending the buffer by one byte

         * (8 bits), which will give some padding.  The second part

         * of the 2's complement negation will do the rest.

         */

        if (p->data_type == OSSL_PARAM_INTEGER && buf_bits % 8 == 0)

            buf_bits += 8;

        *buf_n = (buf_bits + 7) / 8;

        /*

         * A zero data size means "arbitrary size", so only do the

         * range checking if a size is specified.

         */

        if (p->data_size > 0) {

            if (buf_bits > p->data_size * 8) {

                ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_SMALL_BUFFER);

                /* Since this is a different error, we don't break */

                return 0;

            }

            /* Change actual size to become the desired size. */

            *buf_n = p->data_size;

        }

        break;

    case OSSL_PARAM_UTF8_STRING:

        if (*ishex) {

            ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_INVALID_ARGUMENT);

            return 0;

        }

        *buf_n = strlen(value) + 1;

        break;

    case OSSL_PARAM_OCTET_STRING:

        if (*ishex) {

            size_t hexdigits = strlen(value);

            if ((hexdigits % 2) != 0) {

                /* We don't accept an odd number of hex digits */

                ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_ODD_NUMBER_OF_DIGITS);

                return 0;

            }

            *buf_n = hexdigits >> 1;

        } else {

            *buf_n = value_n;

        }

        break;

    }

    return 1;

}

static int construct_from_text(OSSL_PARAM *to, const OSSL_PARAM *paramdef,

                               const char *value, size_t value_n, int ishex,

                               void *buf, size_t buf_n, BIGNUM *tmpbn)

{

    if (buf == NULL)

        return 0;

    if (buf_n > 0) {

        switch (paramdef->data_type) {

        case OSSL_PARAM_INTEGER:

        case OSSL_PARAM_UNSIGNED_INTEGER:

            /*

            {

                if ((new_value = OPENSSL_malloc(new_value_n)) == NULL) {

                    BN_free(a);

                    break;

                }

            */

            BN_bn2nativepad(tmpbn, buf, buf_n);

            /*

             * 2's complement negation, part two.

             *

             * Because we did the first part on the BIGNUM itself, we can just

             * invert all the bytes here and be done with it.

             */

            if (paramdef->data_type == OSSL_PARAM_INTEGER

                && BN_is_negative(tmpbn)) {

                unsigned char *cp;

                size_t i = buf_n;

                for (cp = buf; i-- > 0; cp++)

                    *cp ^= 0xFF;

            }

            break;

        case OSSL_PARAM_UTF8_STRING:

#ifdef CHARSET_EBCDIC

            ebcdic2ascii(buf, value, buf_n);

#else

            strncpy(buf, value, buf_n);

#endif

            /* Don't count the terminating NUL byte as data */

            buf_n--;

            break;

        case OSSL_PARAM_OCTET_STRING:

            if (ishex) {

                size_t l = 0;

                if (!OPENSSL_hexstr2buf_ex(buf, buf_n, &l, value, ':'))

                    return 0;

            } else {

                memcpy(buf, value, buf_n);

            }

            break;

        }

    }

    *to = *paramdef;

    to->data = buf;

    to->data_size = buf_n;

    to->return_size = OSSL_PARAM_UNMODIFIED;

    return 1;

}

int OSSL_PARAM_allocate_from_text(OSSL_PARAM *to,

                                  const OSSL_PARAM *paramdefs,

                                  const char *key, const char *value,

                                  size_t value_n, int *found)

{

    const OSSL_PARAM *paramdef = NULL;

    int ishex = 0;

    void *buf = NULL;

    size_t buf_n = 0;

    BIGNUM *tmpbn = NULL;

    int ok = 0;

    if (to == NULL || paramdefs == NULL)

        return 0;

    if (!prepare_from_text(paramdefs, key, value, value_n,

                           &paramdef, &ishex, &buf_n, &tmpbn, found))

        goto err;

    if ((buf = OPENSSL_zalloc(buf_n > 0 ? buf_n : 1)) == NULL) {

        ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    ok = construct_from_text(to, paramdef, value, value_n, ishex,

                             buf, buf_n, tmpbn);

    BN_free(tmpbn);

    if (!ok)

        OPENSSL_free(buf);

    return ok;

 err:

    BN_free(tmpbn);

    return 0;

}