/*

 * Copyright 1995-2020 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 <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/buffer.h>

/*

 * LIMIT_BEFORE_EXPANSION is the maximum n such that (n+3)/3*4 < 2**31. That

 * function is applied in several functions in this file and this limit

 * ensures that the result fits in an int.

 */

#define LIMIT_BEFORE_EXPANSION 0x5ffffffc

BUF_MEM *BUF_MEM_new_ex(unsigned long flags)

{

    BUF_MEM *ret;

    ret = BUF_MEM_new();

    if (ret != NULL)

        ret->flags = flags;

    return ret;

}

BUF_MEM *BUF_MEM_new(void)

{

    BUF_MEM *ret;

    ret = OPENSSL_zalloc(sizeof(*ret));

    if (ret == NULL) {

        ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    return ret;

}

void BUF_MEM_free(BUF_MEM *a)

{

    if (a == NULL)

        return;

    if (a->data != NULL) {

        if (a->flags & BUF_MEM_FLAG_SECURE)

            OPENSSL_secure_clear_free(a->data, a->max);

        else

            OPENSSL_clear_free(a->data, a->max);

    }

    OPENSSL_free(a);

}

/* Allocate a block of secure memory; copy over old data if there

 * was any, and then free it. */

static char *sec_alloc_realloc(BUF_MEM *str, size_t len)

{

    char *ret;

    ret = OPENSSL_secure_malloc(len);

    if (str->data != NULL) {

        if (ret != NULL) {

            memcpy(ret, str->data, str->length);

            OPENSSL_secure_clear_free(str->data, str->length);

            str->data = NULL;

        }

    }

    return ret;

}

size_t BUF_MEM_grow(BUF_MEM *str, size_t len)

{

    char *ret;

    size_t n;

    if (str->length >= len) {

        str->length = len;

        return len;

    }

    if (str->max >= len) {

        if (str->data != NULL)

            memset(&str->data[str->length], 0, len - str->length);

        str->length = len;

        return len;

    }

    /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */

    if (len > LIMIT_BEFORE_EXPANSION) {

        ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    n = (len + 3) / 3 * 4;

    if ((str->flags & BUF_MEM_FLAG_SECURE))

        ret = sec_alloc_realloc(str, n);

    else

        ret = OPENSSL_realloc(str->data, n);

    if (ret == NULL) {

        ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);

        len = 0;

    } else {

        str->data = ret;

        str->max = n;

        memset(&str->data[str->length], 0, len - str->length);

        str->length = len;

    }

    return len;

}

size_t BUF_MEM_grow_clean(BUF_MEM *str, size_t len)

{

    char *ret;

    size_t n;

    if (str->length >= len) {

        if (str->data != NULL)

            memset(&str->data[len], 0, str->length - len);

        str->length = len;

        return len;

    }

    if (str->max >= len) {

        memset(&str->data[str->length], 0, len - str->length);

        str->length = len;

        return len;

    }

    /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */

    if (len > LIMIT_BEFORE_EXPANSION) {

        ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    n = (len + 3) / 3 * 4;

    if ((str->flags & BUF_MEM_FLAG_SECURE))

        ret = sec_alloc_realloc(str, n);

    else

        ret = OPENSSL_clear_realloc(str->data, str->max, n);

    if (ret == NULL) {

        ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);

        len = 0;

    } else {

        str->data = ret;

        str->max = n;

        memset(&str->data[str->length], 0, len - str->length);

        str->length = len;

    }

    return len;

}

void BUF_reverse(unsigned char *out, const unsigned char *in, size_t size)

{

    size_t i;

    if (in) {

        out += size - 1;

        for (i = 0; i < size; i++)

            *out-- = *in++;

    } else {

        unsigned char *q;

        char c;

        q = out + size - 1;

        for (i = 0; i < size / 2; i++) {

            c = *q;

            *q-- = *out;

            *out++ = c;

        }

    }

}