/*

 * Copyright 2008-2021 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 "crypto/modes.h"

#if !defined(STRICT_ALIGNMENT) && !defined(PEDANTIC)

# define STRICT_ALIGNMENT 0

#endif

#if defined(__GNUC__) && !STRICT_ALIGNMENT

typedef size_t size_t_aX __attribute((__aligned__(1)));

#else

typedef size_t size_t_aX;

#endif

void CRYPTO_cbc128_encrypt(const unsigned char *in, unsigned char *out,

                           size_t len, const void *key,

                           unsigned char ivec[16], block128_f block)

{

    size_t n;

    const unsigned char *iv = ivec;

    if (len == 0)

        return;

#if !defined(OPENSSL_SMALL_FOOTPRINT)

    if (STRICT_ALIGNMENT &&

        ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {

        while (len >= 16) {

            for (n = 0; n < 16; ++n)

                out[n] = in[n] ^ iv[n];

            (*block) (out, out, key);

            iv = out;

            len -= 16;

            in += 16;

            out += 16;

        }

    } else {

        while (len >= 16) {

            for (n = 0; n < 16; n += sizeof(size_t))

                *(size_t_aX *)(out + n) =

                    *(size_t_aX *)(in + n) ^ *(size_t_aX *)(iv + n);

            (*block) (out, out, key);

            iv = out;

            len -= 16;

            in += 16;

            out += 16;

        }

    }

#endif

    while (len) {

        for (n = 0; n < 16 && n < len; ++n)

            out[n] = in[n] ^ iv[n];

        for (; n < 16; ++n)

            out[n] = iv[n];

        (*block) (out, out, key);

        iv = out;

        if (len <= 16)

            break;

        len -= 16;

        in += 16;

        out += 16;

    }

    if (ivec != iv)

        memcpy(ivec, iv, 16);

}

void CRYPTO_cbc128_decrypt(const unsigned char *in, unsigned char *out,

                           size_t len, const void *key,

                           unsigned char ivec[16], block128_f block)

{

    size_t n;

    union {

        size_t t[16 / sizeof(size_t)];

        unsigned char c[16];

    } tmp;

    if (len == 0)

        return;

#if !defined(OPENSSL_SMALL_FOOTPRINT)

    if (in != out) {

        const unsigned char *iv = ivec;

        if (STRICT_ALIGNMENT &&

            ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {

            while (len >= 16) {

                (*block) (in, out, key);

                for (n = 0; n < 16; ++n)

                    out[n] ^= iv[n];

                iv = in;

                len -= 16;

                in += 16;

                out += 16;

            }

        } else if (16 % sizeof(size_t) == 0) { /* always true */

            while (len >= 16) {

                size_t_aX *out_t = (size_t_aX *)out;

                size_t_aX *iv_t = (size_t_aX *)iv;

                (*block) (in, out, key);

                for (n = 0; n < 16 / sizeof(size_t); n++)

                    out_t[n] ^= iv_t[n];

                iv = in;

                len -= 16;

                in += 16;

                out += 16;

            }

        }

        if (ivec != iv)

            memcpy(ivec, iv, 16);

    } else {

        if (STRICT_ALIGNMENT &&

            ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {

            unsigned char c;

            while (len >= 16) {

                (*block) (in, tmp.c, key);

                for (n = 0; n < 16; ++n) {

                    c = in[n];

                    out[n] = tmp.c[n] ^ ivec[n];

                    ivec[n] = c;

                }

                len -= 16;

                in += 16;

                out += 16;

            }

        } else if (16 % sizeof(size_t) == 0) { /* always true */

            while (len >= 16) {

                size_t c;

                size_t_aX *out_t = (size_t_aX *)out;

                size_t_aX *ivec_t = (size_t_aX *)ivec;

                const size_t_aX *in_t = (const size_t_aX *)in;

                (*block) (in, tmp.c, key);

                for (n = 0; n < 16 / sizeof(size_t); n++) {

                    c = in_t[n];

                    out_t[n] = tmp.t[n] ^ ivec_t[n];

                    ivec_t[n] = c;

                }

                len -= 16;

                in += 16;

                out += 16;

            }

        }

    }

#endif

    while (len) {

        unsigned char c;

        (*block) (in, tmp.c, key);

        for (n = 0; n < 16 && n < len; ++n) {

            c = in[n];

            out[n] = tmp.c[n] ^ ivec[n];

            ivec[n] = c;

        }

        if (len <= 16) {

            for (; n < 16; ++n)

                ivec[n] = in[n];

            break;

        }

        len -= 16;

        in += 16;

        out += 16;

    }

}