/*-
 * Copyright (c) 2005-2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * Copyright (c) 2015 Allan Jude <allanjude@FreeBSD.org>
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 AUTHORS OR 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 <stdio.h>
#include <string.h>
#include <strings.h>

#include "geliboot_internal.h"
#include "geliboot.h"

int
geliboot_crypt(u_int algo, geli_op_t enc, u_char *data, size_t datasize,
    const u_char *key, size_t keysize, u_char *iv)
{
        keyInstance aeskey;
        cipherInstance cipher;
        struct aes_xts_ctx xtsctx, *ctxp;
        size_t xts_len;
        int err, blks;

        switch (algo) {
        case CRYPTO_AES_CBC:
                err = rijndael_makeKey(&aeskey, !enc, keysize, 
                    (const char *)key);
                if (err < 0) {
                        printf("Failed to setup crypto keys: %d\n", err);
                        return (err);
                }

                err = rijndael_cipherInit(&cipher, MODE_CBC, iv);
                if (err < 0) {
                        printf("Failed to setup IV: %d\n", err);
                        return (err);
                }

                switch (enc) {
                case GELI_DECRYPT:
                        blks = rijndael_blockDecrypt(&cipher, &aeskey, data, 
                            datasize * 8, data);
                        break;
                case GELI_ENCRYPT:
                        blks = rijndael_blockEncrypt(&cipher, &aeskey, data, 
                            datasize * 8, data);
                        break;
                }
                if (datasize != (blks / 8)) {
                        printf("Failed to %s the entire input: %u != %zu\n",
                            enc ? "decrypt" : "encrypt",
                            blks, datasize);
                        return (1);
                }
                break;
        case CRYPTO_AES_XTS:
                xts_len = keysize << 1;
                ctxp = &xtsctx;

                enc_xform_aes_xts.setkey(ctxp, key, xts_len / 8);
                enc_xform_aes_xts.reinit(ctxp, iv, AES_XTS_IV_LEN);

                switch (enc) {
                case GELI_DECRYPT:
                        enc_xform_aes_xts.decrypt_multi(ctxp, data, data,
                            datasize);
                        break;
                case GELI_ENCRYPT:
                        enc_xform_aes_xts.encrypt_multi(ctxp, data, data,
                            datasize);
                        break;
                }
                break;
        default:
                printf("Unsupported crypto algorithm #%d\n", algo);
                return (1);
        }

        return (0);
}

static int
g_eli_crypto_cipher(u_int algo, geli_op_t enc, u_char *data, size_t datasize,
    const u_char *key, size_t keysize)
{
        u_char iv[G_ELI_IVKEYLEN];

        explicit_bzero(iv, sizeof(iv));
        return (geliboot_crypt(algo, enc, data, datasize, key, keysize, iv));
}

int
g_eli_crypto_encrypt(u_int algo, u_char *data, size_t datasize,
    const u_char *key, size_t keysize)
{

        /* We prefer AES-CBC for metadata protection. */
        if (algo == CRYPTO_AES_XTS)
                algo = CRYPTO_AES_CBC;

        return (g_eli_crypto_cipher(algo, GELI_ENCRYPT, data, datasize, key,
            keysize));
}

int
g_eli_crypto_decrypt(u_int algo, u_char *data, size_t datasize,
    const u_char *key, size_t keysize)
{

        /* We prefer AES-CBC for metadata protection. */
        if (algo == CRYPTO_AES_XTS)
                algo = CRYPTO_AES_CBC;

        return (g_eli_crypto_cipher(algo, GELI_DECRYPT, data, datasize, key,
            keysize));
}