2215adc5ff
It's included by header pollution in most of the compile environments. However, in the standalone envirnment, it's not included. Go ahead and include it always since the overhead is low and it is simpler that way. MFC After: 3 days
158 lines
4.3 KiB
C
158 lines
4.3 KiB
C
/* $OpenBSD: xform.c,v 1.16 2001/08/28 12:20:43 ben Exp $ */
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/*-
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* The authors of this code are John Ioannidis (ji@tla.org),
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* Angelos D. Keromytis (kermit@csd.uch.gr),
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* Niels Provos (provos@physnet.uni-hamburg.de) and
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* Damien Miller (djm@mindrot.org).
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*
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* This code was written by John Ioannidis for BSD/OS in Athens, Greece,
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* in November 1995.
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*
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* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
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* by Angelos D. Keromytis.
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*
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* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
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* and Niels Provos.
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*
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* Additional features in 1999 by Angelos D. Keromytis.
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*
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* AES XTS implementation in 2008 by Damien Miller
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*
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* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
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* Angelos D. Keromytis and Niels Provos.
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*
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* Copyright (C) 2001, Angelos D. Keromytis.
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*
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* Copyright (C) 2008, Damien Miller
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* Copyright (c) 2014 The FreeBSD Foundation
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* All rights reserved.
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*
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* Portions of this software were developed by John-Mark Gurney
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* under sponsorship of the FreeBSD Foundation and
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* Rubicon Communications, LLC (Netgate).
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*
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* Permission to use, copy, and modify this software with or without fee
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* is hereby granted, provided that this entire notice is included in
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* all copies of any software which is or includes a copy or
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* modification of this software.
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* You may use this code under the GNU public license if you so wish. Please
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* contribute changes back to the authors under this freer than GPL license
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* so that we may further the use of strong encryption without limitations to
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* all.
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*
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* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
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* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
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* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
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* PURPOSE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <opencrypto/xform_enc.h>
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static int aes_xts_setkey(void *, const uint8_t *, int);
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static void aes_xts_encrypt(void *, const uint8_t *, uint8_t *);
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static void aes_xts_decrypt(void *, const uint8_t *, uint8_t *);
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static void aes_xts_reinit(void *, const uint8_t *);
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/* Encryption instances */
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struct enc_xform enc_xform_aes_xts = {
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.type = CRYPTO_AES_XTS,
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.name = "AES-XTS",
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.ctxsize = sizeof(struct aes_xts_ctx),
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.blocksize = AES_BLOCK_LEN,
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.ivsize = AES_XTS_IV_LEN,
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.minkey = AES_XTS_MIN_KEY,
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.maxkey = AES_XTS_MAX_KEY,
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.encrypt = aes_xts_encrypt,
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.decrypt = aes_xts_decrypt,
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.setkey = aes_xts_setkey,
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.reinit = aes_xts_reinit
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};
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/*
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* Encryption wrapper routines.
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*/
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static void
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aes_xts_reinit(void *key, const uint8_t *iv)
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{
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struct aes_xts_ctx *ctx = key;
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uint64_t blocknum;
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u_int i;
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/*
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* Prepare tweak as E_k2(IV). IV is specified as LE representation
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* of a 64-bit block number which we allow to be passed in directly.
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*/
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bcopy(iv, &blocknum, AES_XTS_IVSIZE);
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for (i = 0; i < AES_XTS_IVSIZE; i++) {
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ctx->tweak[i] = blocknum & 0xff;
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blocknum >>= 8;
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}
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/* Last 64 bits of IV are always zero */
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bzero(ctx->tweak + AES_XTS_IVSIZE, AES_XTS_IVSIZE);
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rijndael_encrypt(&ctx->key2, ctx->tweak, ctx->tweak);
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}
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static void
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aes_xts_crypt(struct aes_xts_ctx *ctx, const uint8_t *in, uint8_t *out,
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u_int do_encrypt)
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{
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uint8_t block[AES_XTS_BLOCKSIZE];
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u_int i, carry_in, carry_out;
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for (i = 0; i < AES_XTS_BLOCKSIZE; i++)
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block[i] = in[i] ^ ctx->tweak[i];
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if (do_encrypt)
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rijndael_encrypt(&ctx->key1, block, out);
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else
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rijndael_decrypt(&ctx->key1, block, out);
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for (i = 0; i < AES_XTS_BLOCKSIZE; i++)
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out[i] ^= ctx->tweak[i];
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/* Exponentiate tweak */
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carry_in = 0;
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for (i = 0; i < AES_XTS_BLOCKSIZE; i++) {
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carry_out = ctx->tweak[i] & 0x80;
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ctx->tweak[i] = (ctx->tweak[i] << 1) | (carry_in ? 1 : 0);
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carry_in = carry_out;
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}
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if (carry_in)
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ctx->tweak[0] ^= AES_XTS_ALPHA;
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explicit_bzero(block, sizeof(block));
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}
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static void
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aes_xts_encrypt(void *key, const uint8_t *in, uint8_t *out)
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{
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aes_xts_crypt(key, in, out, 1);
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}
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static void
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aes_xts_decrypt(void *key, const uint8_t *in, uint8_t *out)
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{
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aes_xts_crypt(key, in, out, 0);
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}
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static int
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aes_xts_setkey(void *sched, const uint8_t *key, int len)
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{
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struct aes_xts_ctx *ctx;
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if (len != 32 && len != 64)
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return (EINVAL);
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ctx = sched;
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rijndael_set_key(&ctx->key1, key, len * 4);
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rijndael_set_key(&ctx->key2, key + (len / 2), len * 4);
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return (0);
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}
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