d55df8dcf7
Add an IV to the context that is initialized by the reinit hook. Encrypt and decrypt operations handle cipher block chaining along with updating the IV saved in the context. Reviewed by: markj Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D33487
129 lines
3.7 KiB
C
129 lines
3.7 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 <crypto/rijndael/rijndael.h>
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#include <opencrypto/xform_enc.h>
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struct aes_cbc_ctx {
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rijndael_ctx key;
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char iv[AES_BLOCK_LEN];
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};
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static int aes_cbc_setkey(void *, const uint8_t *, int);
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static void aes_cbc_encrypt(void *, const uint8_t *, uint8_t *);
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static void aes_cbc_decrypt(void *, const uint8_t *, uint8_t *);
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static void aes_cbc_reinit(void *, const uint8_t *, size_t);
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/* Encryption instances */
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const struct enc_xform enc_xform_aes_cbc = {
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.type = CRYPTO_AES_CBC,
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.name = "AES-CBC",
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.ctxsize = sizeof(struct aes_cbc_ctx),
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.blocksize = AES_BLOCK_LEN,
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.ivsize = AES_BLOCK_LEN,
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.minkey = AES_MIN_KEY,
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.maxkey = AES_MAX_KEY,
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.encrypt = aes_cbc_encrypt,
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.decrypt = aes_cbc_decrypt,
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.setkey = aes_cbc_setkey,
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.reinit = aes_cbc_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_cbc_encrypt(void *vctx, const uint8_t *in, uint8_t *out)
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{
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struct aes_cbc_ctx *ctx = vctx;
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for (u_int i = 0; i < AES_BLOCK_LEN; i++)
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out[i] = in[i] ^ ctx->iv[i];
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rijndael_encrypt(&ctx->key, out, out);
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memcpy(ctx->iv, out, AES_BLOCK_LEN);
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}
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static void
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aes_cbc_decrypt(void *vctx, const uint8_t *in, uint8_t *out)
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{
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struct aes_cbc_ctx *ctx = vctx;
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char block[AES_BLOCK_LEN];
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memcpy(block, in, AES_BLOCK_LEN);
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rijndael_decrypt(&ctx->key, in, out);
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for (u_int i = 0; i < AES_BLOCK_LEN; i++)
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out[i] ^= ctx->iv[i];
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memcpy(ctx->iv, block, AES_BLOCK_LEN);
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explicit_bzero(block, sizeof(block));
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}
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static int
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aes_cbc_setkey(void *vctx, const uint8_t *key, int len)
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{
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struct aes_cbc_ctx *ctx = vctx;
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if (len != 16 && len != 24 && len != 32)
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return (EINVAL);
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rijndael_set_key(&ctx->key, key, len * 8);
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return (0);
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}
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static void
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aes_cbc_reinit(void *vctx, const uint8_t *iv, size_t iv_len)
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{
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struct aes_cbc_ctx *ctx = vctx;
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KASSERT(iv_len == sizeof(ctx->iv), ("%s: bad IV length", __func__));
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memcpy(ctx->iv, iv, sizeof(ctx->iv));
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}
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