The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/opencrypto/xform_aes_xts.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*      $OpenBSD: xform.c,v 1.16 2001/08/28 12:20:43 ben Exp $  */
    2 /*-
    3  * The authors of this code are John Ioannidis (ji@tla.org),
    4  * Angelos D. Keromytis (kermit@csd.uch.gr),
    5  * Niels Provos (provos@physnet.uni-hamburg.de) and
    6  * Damien Miller (djm@mindrot.org).
    7  *
    8  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
    9  * in November 1995.
   10  *
   11  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
   12  * by Angelos D. Keromytis.
   13  *
   14  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
   15  * and Niels Provos.
   16  *
   17  * Additional features in 1999 by Angelos D. Keromytis.
   18  *
   19  * AES XTS implementation in 2008 by Damien Miller
   20  *
   21  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
   22  * Angelos D. Keromytis and Niels Provos.
   23  *
   24  * Copyright (C) 2001, Angelos D. Keromytis.
   25  *
   26  * Copyright (C) 2008, Damien Miller
   27  * Copyright (c) 2014 The FreeBSD Foundation
   28  * All rights reserved.
   29  *
   30  * Portions of this software were developed by John-Mark Gurney
   31  * under sponsorship of the FreeBSD Foundation and
   32  * Rubicon Communications, LLC (Netgate).
   33  *
   34  * Permission to use, copy, and modify this software with or without fee
   35  * is hereby granted, provided that this entire notice is included in
   36  * all copies of any software which is or includes a copy or
   37  * modification of this software.
   38  * You may use this code under the GNU public license if you so wish. Please
   39  * contribute changes back to the authors under this freer than GPL license
   40  * so that we may further the use of strong encryption without limitations to
   41  * all.
   42  *
   43  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
   44  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
   45  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
   46  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
   47  * PURPOSE.
   48  */
   49 
   50 #include <sys/cdefs.h>
   51 __FBSDID("$FreeBSD: releng/11.1/sys/opencrypto/xform_aes_xts.c 292963 2015-12-30 22:43:07Z allanjude $");
   52 
   53 #include <opencrypto/xform_enc.h>
   54 
   55 static  int aes_xts_setkey(u_int8_t **, u_int8_t *, int);
   56 static  void aes_xts_encrypt(caddr_t, u_int8_t *);
   57 static  void aes_xts_decrypt(caddr_t, u_int8_t *);
   58 static  void aes_xts_zerokey(u_int8_t **);
   59 static  void aes_xts_reinit(caddr_t, u_int8_t *);
   60 
   61 /* Encryption instances */
   62 struct enc_xform enc_xform_aes_xts = {
   63         CRYPTO_AES_XTS, "AES-XTS",
   64         AES_BLOCK_LEN, AES_XTS_IV_LEN, AES_XTS_MIN_KEY, AES_XTS_MAX_KEY,
   65         aes_xts_encrypt,
   66         aes_xts_decrypt,
   67         aes_xts_setkey,
   68         aes_xts_zerokey,
   69         aes_xts_reinit
   70 };
   71 
   72 /*
   73  * Encryption wrapper routines.
   74  */
   75 static void
   76 aes_xts_reinit(caddr_t key, u_int8_t *iv)
   77 {
   78         struct aes_xts_ctx *ctx = (struct aes_xts_ctx *)key;
   79         u_int64_t blocknum;
   80         u_int i;
   81 
   82         /*
   83          * Prepare tweak as E_k2(IV). IV is specified as LE representation
   84          * of a 64-bit block number which we allow to be passed in directly.
   85          */
   86         bcopy(iv, &blocknum, AES_XTS_IVSIZE);
   87         for (i = 0; i < AES_XTS_IVSIZE; i++) {
   88                 ctx->tweak[i] = blocknum & 0xff;
   89                 blocknum >>= 8;
   90         }
   91         /* Last 64 bits of IV are always zero */
   92         bzero(ctx->tweak + AES_XTS_IVSIZE, AES_XTS_IVSIZE);
   93 
   94         rijndael_encrypt(&ctx->key2, ctx->tweak, ctx->tweak);
   95 }
   96 
   97 static void
   98 aes_xts_crypt(struct aes_xts_ctx *ctx, u_int8_t *data, u_int do_encrypt)
   99 {
  100         u_int8_t block[AES_XTS_BLOCKSIZE];
  101         u_int i, carry_in, carry_out;
  102 
  103         for (i = 0; i < AES_XTS_BLOCKSIZE; i++)
  104                 block[i] = data[i] ^ ctx->tweak[i];
  105 
  106         if (do_encrypt)
  107                 rijndael_encrypt(&ctx->key1, block, data);
  108         else
  109                 rijndael_decrypt(&ctx->key1, block, data);
  110 
  111         for (i = 0; i < AES_XTS_BLOCKSIZE; i++)
  112                 data[i] ^= ctx->tweak[i];
  113 
  114         /* Exponentiate tweak */
  115         carry_in = 0;
  116         for (i = 0; i < AES_XTS_BLOCKSIZE; i++) {
  117                 carry_out = ctx->tweak[i] & 0x80;
  118                 ctx->tweak[i] = (ctx->tweak[i] << 1) | (carry_in ? 1 : 0);
  119                 carry_in = carry_out;
  120         }
  121         if (carry_in)
  122                 ctx->tweak[0] ^= AES_XTS_ALPHA;
  123         bzero(block, sizeof(block));
  124 }
  125 
  126 static void
  127 aes_xts_encrypt(caddr_t key, u_int8_t *data)
  128 {
  129         aes_xts_crypt((struct aes_xts_ctx *)key, data, 1);
  130 }
  131 
  132 static void
  133 aes_xts_decrypt(caddr_t key, u_int8_t *data)
  134 {
  135         aes_xts_crypt((struct aes_xts_ctx *)key, data, 0);
  136 }
  137 
  138 static int
  139 aes_xts_setkey(u_int8_t **sched, u_int8_t *key, int len)
  140 {
  141         struct aes_xts_ctx *ctx;
  142 
  143         if (len != 32 && len != 64)
  144                 return EINVAL;
  145 
  146         *sched = KMALLOC(sizeof(struct aes_xts_ctx), M_CRYPTO_DATA,
  147             M_NOWAIT | M_ZERO);
  148         if (*sched == NULL)
  149                 return ENOMEM;
  150         ctx = (struct aes_xts_ctx *)*sched;
  151 
  152         rijndael_set_key(&ctx->key1, key, len * 4);
  153         rijndael_set_key(&ctx->key2, key + (len / 2), len * 4);
  154 
  155         return 0;
  156 }
  157 
  158 static void
  159 aes_xts_zerokey(u_int8_t **sched)
  160 {
  161         bzero(*sched, sizeof(struct aes_xts_ctx));
  162         KFREE(*sched, M_CRYPTO_DATA);
  163         *sched = NULL;
  164 }

Cache object: e9ad6e01d69e8a846b6decd702714c29


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.