/* $OpenBSD: gost2814789.c,v 1.7 2021/11/09 18:40:21 bcook Exp $ */
/*
 * Copyright (c) 2014 Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
 * Copyright (c) 2005-2006 Cryptocom LTD
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 */

#include <endian.h>
#include <string.h>

#include <openssl/opensslconf.h>

#ifndef OPENSSL_NO_GOST
#include <openssl/objects.h>
#include <openssl/gost.h>

#include "gost_locl.h"

static inline unsigned int
f(const GOST2814789_KEY *c, unsigned int x)
{
        return  c->k87[(x>>24) & 255] | c->k65[(x>>16) & 255]|
                c->k43[(x>> 8) & 255] | c->k21[(x    ) & 255];
}

void
Gost2814789_encrypt(const unsigned char *in, unsigned char *out,
    const GOST2814789_KEY *key)
{
        unsigned int n1, n2; /* As named in the GOST */

        c2l(in, n1);
        c2l(in, n2);

        /* Instead of swapping halves, swap names each round */
        n2 ^= f(key, n1 + key->key[0]); n1 ^= f(key, n2 + key->key[1]);
        n2 ^= f(key, n1 + key->key[2]); n1 ^= f(key, n2 + key->key[3]);
        n2 ^= f(key, n1 + key->key[4]); n1 ^= f(key, n2 + key->key[5]);
        n2 ^= f(key, n1 + key->key[6]); n1 ^= f(key, n2 + key->key[7]);

        n2 ^= f(key, n1 + key->key[0]); n1 ^= f(key, n2 + key->key[1]);
        n2 ^= f(key, n1 + key->key[2]); n1 ^= f(key, n2 + key->key[3]);
        n2 ^= f(key, n1 + key->key[4]); n1 ^= f(key, n2 + key->key[5]);
        n2 ^= f(key, n1 + key->key[6]); n1 ^= f(key, n2 + key->key[7]);

        n2 ^= f(key, n1 + key->key[0]); n1 ^= f(key, n2 + key->key[1]);
        n2 ^= f(key, n1 + key->key[2]); n1 ^= f(key, n2 + key->key[3]);
        n2 ^= f(key, n1 + key->key[4]); n1 ^= f(key, n2 + key->key[5]);
        n2 ^= f(key, n1 + key->key[6]); n1 ^= f(key, n2 + key->key[7]);

        n2 ^= f(key, n1 + key->key[7]); n1 ^= f(key, n2 + key->key[6]);
        n2 ^= f(key, n1 + key->key[5]); n1 ^= f(key, n2 + key->key[4]);
        n2 ^= f(key, n1 + key->key[3]); n1 ^= f(key, n2 + key->key[2]);
        n2 ^= f(key, n1 + key->key[1]); n1 ^= f(key, n2 + key->key[0]);

        l2c(n2, out);
        l2c(n1, out);
}

void
Gost2814789_decrypt(const unsigned char *in, unsigned char *out,
    const GOST2814789_KEY *key)
{
        unsigned int n1, n2; /* As named in the GOST */

        c2l(in, n1);
        c2l(in, n2);

        /* Instead of swapping halves, swap names each round */
        n2 ^= f(key, n1 + key->key[0]); n1 ^= f(key, n2 + key->key[1]);
        n2 ^= f(key, n1 + key->key[2]); n1 ^= f(key, n2 + key->key[3]);
        n2 ^= f(key, n1 + key->key[4]); n1 ^= f(key, n2 + key->key[5]);
        n2 ^= f(key, n1 + key->key[6]); n1 ^= f(key, n2 + key->key[7]);

        n2 ^= f(key, n1 + key->key[7]); n1 ^= f(key, n2 + key->key[6]);
        n2 ^= f(key, n1 + key->key[5]); n1 ^= f(key, n2 + key->key[4]);
        n2 ^= f(key, n1 + key->key[3]); n1 ^= f(key, n2 + key->key[2]);
        n2 ^= f(key, n1 + key->key[1]); n1 ^= f(key, n2 + key->key[0]);

        n2 ^= f(key, n1 + key->key[7]); n1 ^= f(key, n2 + key->key[6]);
        n2 ^= f(key, n1 + key->key[5]); n1 ^= f(key, n2 + key->key[4]);
        n2 ^= f(key, n1 + key->key[3]); n1 ^= f(key, n2 + key->key[2]);
        n2 ^= f(key, n1 + key->key[1]); n1 ^= f(key, n2 + key->key[0]);

        n2 ^= f(key, n1 + key->key[7]); n1 ^= f(key, n2 + key->key[6]);
        n2 ^= f(key, n1 + key->key[5]); n1 ^= f(key, n2 + key->key[4]);
        n2 ^= f(key, n1 + key->key[3]); n1 ^= f(key, n2 + key->key[2]);
        n2 ^= f(key, n1 + key->key[1]); n1 ^= f(key, n2 + key->key[0]);

        l2c(n2, out);
        l2c(n1, out);
}

static void
Gost2814789_mac(const unsigned char *in, unsigned char *mac,
    GOST2814789_KEY *key)
{
        unsigned int n1, n2; /* As named in the GOST */
        unsigned char *p;
        int i;

        for (i = 0; i < 8; i++)
                mac[i] ^= in[i];

        p = mac;
        c2l(p, n1);
        c2l(p, n2);

        /* Instead of swapping halves, swap names each round */
        n2 ^= f(key, n1 + key->key[0]); n1 ^= f(key, n2 + key->key[1]);
        n2 ^= f(key, n1 + key->key[2]); n1 ^= f(key, n2 + key->key[3]);
        n2 ^= f(key, n1 + key->key[4]); n1 ^= f(key, n2 + key->key[5]);
        n2 ^= f(key, n1 + key->key[6]); n1 ^= f(key, n2 + key->key[7]);

        n2 ^= f(key, n1 + key->key[0]); n1 ^= f(key, n2 + key->key[1]);
        n2 ^= f(key, n1 + key->key[2]); n1 ^= f(key, n2 + key->key[3]);
        n2 ^= f(key, n1 + key->key[4]); n1 ^= f(key, n2 + key->key[5]);
        n2 ^= f(key, n1 + key->key[6]); n1 ^= f(key, n2 + key->key[7]);

        p = mac;
        l2c(n1, p);
        l2c(n2, p);
}

void
Gost2814789_ecb_encrypt(const unsigned char *in, unsigned char *out,
    GOST2814789_KEY *key, const int enc)
{
        if (key->key_meshing && key->count == 1024) {
                Gost2814789_cryptopro_key_mesh(key);
                key->count = 0;
        }

        if (enc)
                Gost2814789_encrypt(in, out, key);
        else
                Gost2814789_decrypt(in, out, key);
}

static inline void
Gost2814789_encrypt_mesh(unsigned char *iv, GOST2814789_KEY *key)
{
        if (key->key_meshing && key->count == 1024) {
                Gost2814789_cryptopro_key_mesh(key);
                Gost2814789_encrypt(iv, iv, key);
                key->count = 0;
        }
        Gost2814789_encrypt(iv, iv, key);
        key->count += 8;
}

static inline void
Gost2814789_mac_mesh(const unsigned char *data, unsigned char *mac,
    GOST2814789_KEY *key)
{
        if (key->key_meshing && key->count == 1024) {
                Gost2814789_cryptopro_key_mesh(key);
                key->count = 0;
        }
        Gost2814789_mac(data, mac, key);
        key->count += 8;
}

void
Gost2814789_cfb64_encrypt(const unsigned char *in, unsigned char *out,
    size_t len, GOST2814789_KEY *key, unsigned char *ivec, int *num,
    const int enc)
{
        unsigned int n;
        size_t l = 0;

        n = *num;

        if (enc) {
#if !defined(OPENSSL_SMALL_FOOTPRINT)
                if (8 % sizeof(size_t) == 0) do { /* always true actually */
                        while (n && len) {
                                *(out++) = ivec[n] ^= *(in++);
                                --len;
                                n = (n + 1) % 8;
                        }
#ifdef __STRICT_ALIGNMENT
                        if (((size_t)in | (size_t)out | (size_t)ivec) %
                            sizeof(size_t) != 0)
                                break;
#endif
                        while (len >= 8) {
                                Gost2814789_encrypt_mesh(ivec, key);
                                for (; n < 8; n += sizeof(size_t)) {
                                        *(size_t*)(out + n) =
                                        *(size_t*)(ivec + n) ^=
                                            *(size_t*)(in + n);
                                }
                                len -= 8;
                                out += 8;
                                in  += 8;
                                n = 0;
                        }
                        if (len) {
                                Gost2814789_encrypt_mesh(ivec, key);
                                while (len--) {
                                        out[n] = ivec[n] ^= in[n];
                                        ++n;
                                }
                        }
                        *num = n;
                        return;
                } while (0);
                /* the rest would be commonly eliminated by x86* compiler */
#endif
                while (l<len) {
                        if (n == 0) {
                                Gost2814789_encrypt_mesh(ivec, key);
                        }
                        out[l] = ivec[n] ^= in[l];
                        ++l;
                        n = (n + 1) % 8;
                }
                *num = n;
        } else {
#if !defined(OPENSSL_SMALL_FOOTPRINT)
                if (8 % sizeof(size_t) == 0) do { /* always true actually */
                        while (n && len) {
                                unsigned char c;

                                *(out++) = ivec[n] ^ (c = *(in++));
                                ivec[n] = c;
                                --len;
                                n = (n + 1) % 8;
                        }
#ifdef __STRICT_ALIGNMENT
                        if (((size_t)in | (size_t)out | (size_t)ivec) %
                            sizeof(size_t) != 0)
                                break;
#endif
                        while (len >= 8) {
                                Gost2814789_encrypt_mesh(ivec, key);
                                for (; n < 8; n += sizeof(size_t)) {
                                        size_t t = *(size_t*)(in + n);
                                        *(size_t*)(out + n) =
                                            *(size_t*)(ivec + n) ^ t;
                                        *(size_t*)(ivec + n) = t;
                                }
                                len -= 8;
                                out += 8;
                                in  += 8;
                                n = 0;
                        }
                        if (len) {
                                Gost2814789_encrypt_mesh(ivec, key);
                                while (len--) {
                                        unsigned char c;

                                        out[n] = ivec[n] ^ (c = in[n]);
                                        ivec[n] = c;
                                        ++n;
                                }
                        }
                        *num = n;
                        return;
                } while (0);
                /* the rest would be commonly eliminated by x86* compiler */
#endif
                while (l < len) {
                        unsigned char c;

                        if (n == 0) {
                                Gost2814789_encrypt_mesh(ivec, key);
                        }
                        out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;
                        ++l;
                        n = (n + 1) % 8;
                }
                *num = n;
        }
}

static inline void
Gost2814789_cnt_next(unsigned char *ivec, unsigned char *out,
    GOST2814789_KEY *key)
{
        unsigned char *p = ivec, *p2 = ivec;
        unsigned int val, val2;

        if (key->count == 0)
                Gost2814789_encrypt(ivec, ivec, key);

        if (key->key_meshing && key->count == 1024) {
                Gost2814789_cryptopro_key_mesh(key);
                Gost2814789_encrypt(ivec, ivec, key);
                key->count = 0;
        }

        c2l(p, val);
        val2 = val + 0x01010101;
        l2c(val2, p2);

        c2l(p, val);
        val2 = val + 0x01010104;
        if (val > val2) /* overflow */
                val2++;
        l2c(val2, p2);

        Gost2814789_encrypt(ivec, out, key);
        key->count += 8;
}

void
Gost2814789_cnt_encrypt(const unsigned char *in, unsigned char *out, size_t len,
    GOST2814789_KEY *key, unsigned char *ivec, unsigned char *cnt_buf, int *num)
{
        unsigned int n;
        size_t l = 0;

        n = *num;

#if !defined(OPENSSL_SMALL_FOOTPRINT)
        if (8 % sizeof(size_t) == 0) do { /* always true actually */
                while (n && len) {
                        *(out++) = *(in++) ^ cnt_buf[n];
                        --len;
                        n = (n + 1) % 8;
                }

#ifdef __STRICT_ALIGNMENT
                if (((size_t)in | (size_t)out | (size_t)ivec) %
                    sizeof(size_t) != 0)
                        break;
#endif
                while (len >= 8) {
                        Gost2814789_cnt_next(ivec, cnt_buf, key);
                        for (; n < 8; n += sizeof(size_t))
                                *(size_t *)(out + n) = *(size_t *)(in + n) ^
                                    *(size_t *)(cnt_buf + n);
                        len -= 8;
                        out += 8;
                        in  += 8;
                        n = 0;
                }
                if (len) {
                        Gost2814789_cnt_next(ivec, cnt_buf, key);
                        while (len--) {
                                out[n] = in[n] ^ cnt_buf[n];
                                ++n;
                        }
                }
                *num = n;
                return;
        } while(0);
        /* the rest would be commonly eliminated by x86* compiler */
#endif
        while (l < len) {
                if (n==0)
                        Gost2814789_cnt_next(ivec, cnt_buf, key);
                out[l] = in[l] ^ cnt_buf[n];
                ++l;
                n = (n + 1) % 8;
        }

        *num=n;
}

int
GOST2814789IMIT_Init(GOST2814789IMIT_CTX *c, int nid)
{
        c->Nl = c->Nh = c->num = 0;
        memset(c->mac, 0, 8);
        return Gost2814789_set_sbox(&c->cipher, nid);
}

static void
GOST2814789IMIT_block_data_order(GOST2814789IMIT_CTX *ctx,
    const unsigned char *p, size_t num)
{
        int i;

        for (i = 0; i < num; i++) {
                Gost2814789_mac_mesh(p, ctx->mac, &ctx->cipher);
                p += 8;
        }
}

#define DATA_ORDER_IS_LITTLE_ENDIAN

#define HASH_CBLOCK     GOST2814789IMIT_CBLOCK
#define HASH_LONG       GOST2814789IMIT_LONG
#define HASH_CTX        GOST2814789IMIT_CTX
#define HASH_UPDATE     GOST2814789IMIT_Update
#define HASH_TRANSFORM  GOST2814789IMIT_Transform
#define HASH_NO_FINAL   1
#define HASH_BLOCK_DATA_ORDER   GOST2814789IMIT_block_data_order

#include "md32_common.h"

int
GOST2814789IMIT_Final(unsigned char *md, GOST2814789IMIT_CTX *c)
{
        if (c->num) {
                memset(c->data + c->num, 0, 8 - c->num);
                Gost2814789_mac_mesh(c->data, c->mac, &c->cipher);
        }
        if (c->Nl <= 8 * 8 && c->Nl > 0 && c->Nh == 0) {
                memset(c->data, 0, 8);
                Gost2814789_mac_mesh(c->data, c->mac, &c->cipher);
        }
        memcpy(md, c->mac, 4);
        return 1;
}

unsigned char *
GOST2814789IMIT(const unsigned char *d, size_t n, unsigned char *md, int nid,
    const unsigned char *key, const unsigned char *iv)
{
        GOST2814789IMIT_CTX c;
        static unsigned char m[GOST2814789IMIT_LENGTH];

        if (md == NULL)
                md = m;
        GOST2814789IMIT_Init(&c, nid);
        memcpy(c.mac, iv, 8);
        Gost2814789_set_key(&c.cipher, key, 256);
        GOST2814789IMIT_Update(&c, d, n);
        GOST2814789IMIT_Final(md, &c);
        explicit_bzero(&c, sizeof(c));
        return (md);
}

#endif