/*      $OpenBSD: xform.c,v 1.16 2001/08/28 12:20:43 ben Exp $  */
/*-
 * The authors of this code are John Ioannidis (ji@tla.org),
 * Angelos D. Keromytis (kermit@csd.uch.gr),
 * Niels Provos (provos@physnet.uni-hamburg.de) and
 * Damien Miller (djm@mindrot.org).
 *
 * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
 * in November 1995.
 *
 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
 * by Angelos D. Keromytis.
 *
 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
 * and Niels Provos.
 *
 * Additional features in 1999 by Angelos D. Keromytis.
 *
 * AES XTS implementation in 2008 by Damien Miller
 *
 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
 * Angelos D. Keromytis and Niels Provos.
 *
 * Copyright (C) 2001, Angelos D. Keromytis.
 *
 * Copyright (C) 2008, Damien Miller
 * Copyright (c) 2014 The FreeBSD Foundation
 * All rights reserved.
 *
 * Portions of this software were developed by John-Mark Gurney
 * under sponsorship of the FreeBSD Foundation and
 * Rubicon Communications, LLC (Netgate).
 *
 * Permission to use, copy, and modify this software with or without fee
 * is hereby granted, provided that this entire notice is included in
 * all copies of any software which is or includes a copy or
 * modification of this software.
 * You may use this code under the GNU public license if you so wish. Please
 * contribute changes back to the authors under this freer than GPL license
 * so that we may further the use of strong encryption without limitations to
 * all.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
 * PURPOSE.
 */

#include <sys/cdefs.h>
#include <opencrypto/cbc_mac.h>
#include <opencrypto/gmac.h>
#include <opencrypto/xform_enc.h>

struct aes_gcm_ctx {
        struct aes_icm_ctx cipher;
        struct aes_gmac_ctx gmac;
};

struct aes_ccm_ctx {
        struct aes_icm_ctx cipher;
        struct aes_cbc_mac_ctx cbc_mac;
};

static  int aes_icm_setkey(void *, const uint8_t *, int);
static  void aes_icm_crypt(void *, const uint8_t *, uint8_t *);
static  void aes_icm_crypt_multi(void *, const uint8_t *, uint8_t *, size_t);
static  void aes_icm_crypt_last(void *, const uint8_t *, uint8_t *, size_t);
static  void aes_icm_reinit(void *, const uint8_t *, size_t);
static  int aes_gcm_setkey(void *, const uint8_t *, int);
static  void aes_gcm_reinit(void *, const uint8_t *, size_t);
static  int aes_gcm_update(void *, const void *, u_int);
static  void aes_gcm_final(uint8_t *, void *);
static  int aes_ccm_setkey(void *, const uint8_t *, int);
static  void aes_ccm_reinit(void *, const uint8_t *, size_t);
static  int aes_ccm_update(void *, const void *, u_int);
static  void aes_ccm_final(uint8_t *, void *);

/* Encryption instances */
const struct enc_xform enc_xform_aes_icm = {
        .type = CRYPTO_AES_ICM,
        .name = "AES-ICM",
        .ctxsize = sizeof(struct aes_icm_ctx),
        .blocksize = 1,
        .native_blocksize = AES_BLOCK_LEN,
        .ivsize = AES_BLOCK_LEN,
        .minkey = AES_MIN_KEY,
        .maxkey = AES_MAX_KEY,
        .setkey = aes_icm_setkey,
        .reinit = aes_icm_reinit,
        .encrypt = aes_icm_crypt,
        .decrypt = aes_icm_crypt,
        .encrypt_multi = aes_icm_crypt_multi,
        .decrypt_multi = aes_icm_crypt_multi,
        .encrypt_last = aes_icm_crypt_last,
        .decrypt_last = aes_icm_crypt_last,
};

const struct enc_xform enc_xform_aes_nist_gcm = {
        .type = CRYPTO_AES_NIST_GCM_16,
        .name = "AES-GCM",
        .ctxsize = sizeof(struct aes_gcm_ctx),
        .blocksize = 1,
        .native_blocksize = AES_BLOCK_LEN,
        .ivsize = AES_GCM_IV_LEN,
        .minkey = AES_MIN_KEY,
        .maxkey = AES_MAX_KEY,
        .macsize = AES_GMAC_HASH_LEN,
        .setkey = aes_gcm_setkey,
        .reinit = aes_gcm_reinit,
        .encrypt = aes_icm_crypt,
        .decrypt = aes_icm_crypt,
        .encrypt_multi = aes_icm_crypt_multi,
        .decrypt_multi = aes_icm_crypt_multi,
        .encrypt_last = aes_icm_crypt_last,
        .decrypt_last = aes_icm_crypt_last,
        .update = aes_gcm_update,
        .final = aes_gcm_final,
};

const struct enc_xform enc_xform_ccm = {
        .type = CRYPTO_AES_CCM_16,
        .name = "AES-CCM",
        .ctxsize = sizeof(struct aes_ccm_ctx),
        .blocksize = 1,
        .native_blocksize = AES_BLOCK_LEN,
        .ivsize = AES_CCM_IV_LEN,
        .minkey = AES_MIN_KEY, .maxkey = AES_MAX_KEY,
        .macsize = AES_CBC_MAC_HASH_LEN,
        .setkey = aes_ccm_setkey,
        .reinit = aes_ccm_reinit,
        .encrypt = aes_icm_crypt,
        .decrypt = aes_icm_crypt,
        .encrypt_multi = aes_icm_crypt_multi,
        .decrypt_multi = aes_icm_crypt_multi,
        .encrypt_last = aes_icm_crypt_last,
        .decrypt_last = aes_icm_crypt_last,
        .update = aes_ccm_update,
        .final = aes_ccm_final,
};

/*
 * Encryption wrapper routines.
 */
static void
aes_icm_reinit(void *key, const uint8_t *iv, size_t ivlen)
{
        struct aes_icm_ctx *ctx;

        ctx = key;
        KASSERT(ivlen <= sizeof(ctx->ac_block),
            ("%s: ivlen too large", __func__));
        bcopy(iv, ctx->ac_block, ivlen);
}

static void
aes_gcm_reinit(void *vctx, const uint8_t *iv, size_t ivlen)
{
        struct aes_gcm_ctx *ctx = vctx;

        KASSERT(ivlen == AES_GCM_IV_LEN,
            ("%s: invalid IV length", __func__));
        aes_icm_reinit(&ctx->cipher, iv, ivlen);

        /* GCM starts with 2 as counter 1 is used for final xor of tag. */
        bzero(&ctx->cipher.ac_block[AESICM_BLOCKSIZE - 4], 4);
        ctx->cipher.ac_block[AESICM_BLOCKSIZE - 1] = 2;

        AES_GMAC_Reinit(&ctx->gmac, iv, ivlen);
}

static void
aes_ccm_reinit(void *vctx, const uint8_t *iv, size_t ivlen)
{
        struct aes_ccm_ctx *ctx = vctx;

        KASSERT(ivlen >= 7 && ivlen <= 13,
            ("%s: invalid IV length", __func__));

        /* CCM has flags, then the IV, then the counter, which starts at 1 */
        bzero(ctx->cipher.ac_block, sizeof(ctx->cipher.ac_block));
        ctx->cipher.ac_block[0] = (15 - ivlen) - 1;
        bcopy(iv, ctx->cipher.ac_block + 1, ivlen);
        ctx->cipher.ac_block[AESICM_BLOCKSIZE - 1] = 1;

        AES_CBC_MAC_Reinit(&ctx->cbc_mac, iv, ivlen);
}

static void
aes_icm_crypt(void *key, const uint8_t *in, uint8_t *out)
{
        struct aes_icm_ctx *ctx;
        int i;

        ctx = key;
        aes_icm_crypt_last(key, in, out, AESICM_BLOCKSIZE);

        /* increment counter */
        for (i = AESICM_BLOCKSIZE - 1;
             i >= 0; i--)
                if (++ctx->ac_block[i])   /* continue on overflow */
                        break;
}

static void
aes_icm_crypt_multi(void *key, const uint8_t *in, uint8_t *out, size_t len)
{
        struct aes_icm_ctx *ctx = key;
        uint8_t keystream[AESICM_BLOCKSIZE];
        int i;

        KASSERT(len % AESICM_BLOCKSIZE == 0, ("%s: invalid length", __func__));
        while (len > 0) {
                rijndaelEncrypt(ctx->ac_ek, ctx->ac_nr, ctx->ac_block, keystream);
                for (i = 0; i < AESICM_BLOCKSIZE; i++)
                        out[i] = in[i] ^ keystream[i];

                /* increment counter */
                for (i = AESICM_BLOCKSIZE - 1; i >= 0; i--)
                        if (++ctx->ac_block[i])   /* continue on overflow */
                                break;

                out += AESICM_BLOCKSIZE;
                in += AESICM_BLOCKSIZE;
                len -= AESICM_BLOCKSIZE;
        }
        explicit_bzero(keystream, sizeof(keystream));
}

static void
aes_icm_crypt_last(void *key, const uint8_t *in, uint8_t *out, size_t len)
{
        struct aes_icm_ctx *ctx;
        uint8_t keystream[AESICM_BLOCKSIZE];
        int i;

        ctx = key;
        rijndaelEncrypt(ctx->ac_ek, ctx->ac_nr, ctx->ac_block, keystream);
        for (i = 0; i < len; i++)
                out[i] = in[i] ^ keystream[i];
        explicit_bzero(keystream, sizeof(keystream));
}

static int
aes_icm_setkey(void *sched, const uint8_t *key, int len)
{
        struct aes_icm_ctx *ctx;

        if (len != 16 && len != 24 && len != 32)
                return (EINVAL);

        ctx = sched;
        ctx->ac_nr = rijndaelKeySetupEnc(ctx->ac_ek, key, len * 8);
        return (0);
}

static int
aes_gcm_setkey(void *vctx, const uint8_t *key, int len)
{
        struct aes_gcm_ctx *ctx = vctx;
        int error;

        error = aes_icm_setkey(&ctx->cipher, key, len);
        if (error != 0)
                return (error);

        AES_GMAC_Setkey(&ctx->gmac, key, len);
        return (0);
}

static int
aes_ccm_setkey(void *vctx, const uint8_t *key, int len)
{
        struct aes_ccm_ctx *ctx = vctx;
        int error;

        error = aes_icm_setkey(&ctx->cipher, key, len);
        if (error != 0)
                return (error);

        AES_CBC_MAC_Setkey(&ctx->cbc_mac, key, len);
        return (0);
}

static int
aes_gcm_update(void *vctx, const void *buf, u_int len)
{
        struct aes_gcm_ctx *ctx = vctx;

        return (AES_GMAC_Update(&ctx->gmac, buf, len));
}

static int
aes_ccm_update(void *vctx, const void *buf, u_int len)
{
        struct aes_ccm_ctx *ctx = vctx;

        return (AES_CBC_MAC_Update(&ctx->cbc_mac, buf, len));
}

static void
aes_gcm_final(uint8_t *tag, void *vctx)
{
        struct aes_gcm_ctx *ctx = vctx;

        AES_GMAC_Final(tag, &ctx->gmac);
}

static void
aes_ccm_final(uint8_t *tag, void *vctx)
{
        struct aes_ccm_ctx *ctx = vctx;

        AES_CBC_MAC_Final(tag, &ctx->cbc_mac);
}