/*

 * Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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 "internal/cryptlib.h"

#include <openssl/aes.h>

#include "aes_local.h"

#define N_WORDS (AES_BLOCK_SIZE / sizeof(unsigned long))

typedef struct {

    unsigned long data[N_WORDS];

} aes_block_t;

/* XXX: probably some better way to do this */

#if defined(__i386__) || defined(__x86_64__)

# define UNALIGNED_MEMOPS_ARE_FAST 1

#else

# define UNALIGNED_MEMOPS_ARE_FAST 0

#endif

#if UNALIGNED_MEMOPS_ARE_FAST

# define load_block(d, s)        (d) = *(const aes_block_t *)(s)

# define store_block(d, s)       *(aes_block_t *)(d) = (s)

#else

# define load_block(d, s)        memcpy((d).data, (s), AES_BLOCK_SIZE)

# define store_block(d, s)       memcpy((d), (s).data, AES_BLOCK_SIZE)

#endif

/* N.B. The IV for this mode is _twice_ the block size */

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

                     size_t length, const AES_KEY *key,

                     unsigned char *ivec, const int enc)

{

    size_t n;

    size_t len = length;

    if (length == 0)

        return;

    OPENSSL_assert(in && out && key && ivec);

    OPENSSL_assert((AES_ENCRYPT == enc) || (AES_DECRYPT == enc));

    OPENSSL_assert((length % AES_BLOCK_SIZE) == 0);

    len = length / AES_BLOCK_SIZE;

    if (AES_ENCRYPT == enc) {

        if (in != out &&

            (UNALIGNED_MEMOPS_ARE_FAST

             || ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(long) ==

             0)) {

            aes_block_t *ivp = (aes_block_t *) ivec;

            aes_block_t *iv2p = (aes_block_t *) (ivec + AES_BLOCK_SIZE);

            while (len) {

                aes_block_t *inp = (aes_block_t *) in;

                aes_block_t *outp = (aes_block_t *) out;

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

                    outp->data[n] = inp->data[n] ^ ivp->data[n];

                AES_encrypt((unsigned char *)outp->data,

                            (unsigned char *)outp->data, key);

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

                    outp->data[n] ^= iv2p->data[n];

                ivp = outp;

                iv2p = inp;

                --len;

                in += AES_BLOCK_SIZE;

                out += AES_BLOCK_SIZE;

            }

            memcpy(ivec, ivp->data, AES_BLOCK_SIZE);

            memcpy(ivec + AES_BLOCK_SIZE, iv2p->data, AES_BLOCK_SIZE);

        } else {

            aes_block_t tmp, tmp2;

            aes_block_t iv;

            aes_block_t iv2;

            load_block(iv, ivec);

            load_block(iv2, ivec + AES_BLOCK_SIZE);

            while (len) {

                load_block(tmp, in);

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

                    tmp2.data[n] = tmp.data[n] ^ iv.data[n];

                AES_encrypt((unsigned char *)tmp2.data,

                            (unsigned char *)tmp2.data, key);

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

                    tmp2.data[n] ^= iv2.data[n];

                store_block(out, tmp2);

                iv = tmp2;

                iv2 = tmp;

                --len;

                in += AES_BLOCK_SIZE;

                out += AES_BLOCK_SIZE;

            }

            memcpy(ivec, iv.data, AES_BLOCK_SIZE);

            memcpy(ivec + AES_BLOCK_SIZE, iv2.data, AES_BLOCK_SIZE);

        }

    } else {

        if (in != out &&

            (UNALIGNED_MEMOPS_ARE_FAST

             || ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(long) ==

             0)) {

            aes_block_t *ivp = (aes_block_t *) ivec;

            aes_block_t *iv2p = (aes_block_t *) (ivec + AES_BLOCK_SIZE);

            while (len) {

                aes_block_t tmp;

                aes_block_t *inp = (aes_block_t *) in;

                aes_block_t *outp = (aes_block_t *) out;

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

                    tmp.data[n] = inp->data[n] ^ iv2p->data[n];

                AES_decrypt((unsigned char *)tmp.data,

                            (unsigned char *)outp->data, key);

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

                    outp->data[n] ^= ivp->data[n];

                ivp = inp;

                iv2p = outp;

                --len;

                in += AES_BLOCK_SIZE;

                out += AES_BLOCK_SIZE;

            }

            memcpy(ivec, ivp->data, AES_BLOCK_SIZE);

            memcpy(ivec + AES_BLOCK_SIZE, iv2p->data, AES_BLOCK_SIZE);

        } else {

            aes_block_t tmp, tmp2;

            aes_block_t iv;

            aes_block_t iv2;

            load_block(iv, ivec);

            load_block(iv2, ivec + AES_BLOCK_SIZE);

            while (len) {

                load_block(tmp, in);

                tmp2 = tmp;

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

                    tmp.data[n] ^= iv2.data[n];

                AES_decrypt((unsigned char *)tmp.data,

                            (unsigned char *)tmp.data, key);

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

                    tmp.data[n] ^= iv.data[n];

                store_block(out, tmp);

                iv = tmp2;

                iv2 = tmp;

                --len;

                in += AES_BLOCK_SIZE;

                out += AES_BLOCK_SIZE;

            }

            memcpy(ivec, iv.data, AES_BLOCK_SIZE);

            memcpy(ivec + AES_BLOCK_SIZE, iv2.data, AES_BLOCK_SIZE);

        }

    }

}

/*

 * Note that its effectively impossible to do biIGE in anything other

 * than a single pass, so no provision is made for chaining.

 */

/* N.B. The IV for this mode is _four times_ the block size */

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

                        size_t length, const AES_KEY *key,

                        const AES_KEY *key2, const unsigned char *ivec,

                        const int enc)

{

    size_t n;

    size_t len = length;

    unsigned char tmp[AES_BLOCK_SIZE];

    unsigned char tmp2[AES_BLOCK_SIZE];

    unsigned char tmp3[AES_BLOCK_SIZE];

    unsigned char prev[AES_BLOCK_SIZE];

    const unsigned char *iv;

    const unsigned char *iv2;

    OPENSSL_assert(in && out && key && ivec);

    OPENSSL_assert((AES_ENCRYPT == enc) || (AES_DECRYPT == enc));

    OPENSSL_assert((length % AES_BLOCK_SIZE) == 0);

    if (AES_ENCRYPT == enc) {

        /*

         * XXX: Do a separate case for when in != out (strictly should check

         * for overlap, too)

         */

        /* First the forward pass */

        iv = ivec;

        iv2 = ivec + AES_BLOCK_SIZE;

        while (len >= AES_BLOCK_SIZE) {

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

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

            AES_encrypt(out, out, key);

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

                out[n] ^= iv2[n];

            iv = out;

            memcpy(prev, in, AES_BLOCK_SIZE);

            iv2 = prev;

            len -= AES_BLOCK_SIZE;

            in += AES_BLOCK_SIZE;

            out += AES_BLOCK_SIZE;

        }

        /* And now backwards */

        iv = ivec + AES_BLOCK_SIZE * 2;

        iv2 = ivec + AES_BLOCK_SIZE * 3;

        len = length;

        while (len >= AES_BLOCK_SIZE) {

            out -= AES_BLOCK_SIZE;

            /*

             * XXX: reduce copies by alternating between buffers

             */

            memcpy(tmp, out, AES_BLOCK_SIZE);

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

                out[n] ^= iv[n];

            /*

             * hexdump(stdout, "out ^ iv", out, AES_BLOCK_SIZE);

             */

            AES_encrypt(out, out, key);

            /*

             * hexdump(stdout,"enc", out, AES_BLOCK_SIZE);

             */

            /*

             * hexdump(stdout,"iv2", iv2, AES_BLOCK_SIZE);

             */

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

                out[n] ^= iv2[n];

            /*

             * hexdump(stdout,"out", out, AES_BLOCK_SIZE);

             */

            iv = out;

            memcpy(prev, tmp, AES_BLOCK_SIZE);

            iv2 = prev;

            len -= AES_BLOCK_SIZE;

        }

    } else {

        /* First backwards */

        iv = ivec + AES_BLOCK_SIZE * 2;

        iv2 = ivec + AES_BLOCK_SIZE * 3;

        in += length;

        out += length;

        while (len >= AES_BLOCK_SIZE) {

            in -= AES_BLOCK_SIZE;

            out -= AES_BLOCK_SIZE;

            memcpy(tmp, in, AES_BLOCK_SIZE);

            memcpy(tmp2, in, AES_BLOCK_SIZE);

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

                tmp[n] ^= iv2[n];

            AES_decrypt(tmp, out, key);

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

                out[n] ^= iv[n];

            memcpy(tmp3, tmp2, AES_BLOCK_SIZE);

            iv = tmp3;

            iv2 = out;

            len -= AES_BLOCK_SIZE;

        }

        /* And now forwards */

        iv = ivec;

        iv2 = ivec + AES_BLOCK_SIZE;

        len = length;

        while (len >= AES_BLOCK_SIZE) {

            memcpy(tmp, out, AES_BLOCK_SIZE);

            memcpy(tmp2, out, AES_BLOCK_SIZE);

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

                tmp[n] ^= iv2[n];

            AES_decrypt(tmp, out, key);

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

                out[n] ^= iv[n];

            memcpy(tmp3, tmp2, AES_BLOCK_SIZE);

            iv = tmp3;

            iv2 = out;

            len -= AES_BLOCK_SIZE;

            in += AES_BLOCK_SIZE;

            out += AES_BLOCK_SIZE;

        }

    }

}