lib/libcrypto/modes/ofb128.c

   1 /* $OpenBSD: ofb128.c,v 1.4 2015/02/10 09:46:30 miod Exp $ */
   2 /* ====================================================================
   3  * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the OpenSSL Project
  20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  21  *
  22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission. For written permission, please contact
  25  *    openssl-core@openssl.org.
  26  *
  27  * 5. Products derived from this software may not be called "OpenSSL"
  28  *    nor may "OpenSSL" appear in their names without prior written
  29  *    permission of the OpenSSL Project.
  30  *
  31  * 6. Redistributions of any form whatsoever must retain the following
  32  *    acknowledgment:
  33  *    "This product includes software developed by the OpenSSL Project
  34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  47  * OF THE POSSIBILITY OF SUCH DAMAGE.
  48  * ====================================================================
  49  *
  50  */
  51
  52 #include <openssl/crypto.h>
  53 #include "modes_lcl.h"
  54 #include <string.h>
  55
  56 #ifndef MODES_DEBUG
  57 # ifndef NDEBUG
  58 #  define NDEBUG
  59 # endif
  60 #endif
  61
  62 /* The input and output encrypted as though 128bit ofb mode is being
  63  * used.  The extra state information to record how much of the
  64  * 128bit block we have used is contained in *num;
  65  */
  66 void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
  67                         size_t len, const void *key,
  68                         unsigned char ivec[16], int *num,
  69                         block128_f block)
  70 {
  71         unsigned int n;
  72         size_t l=0;
  73
  74         n = *num;
  75
  76 #if !defined(OPENSSL_SMALL_FOOTPRINT)
  77         if (16%sizeof(size_t) == 0) do { /* always true actually */
  78                 while (n && len) {
  79                         *(out++) = *(in++) ^ ivec[n];
  80                         --len;
  81                         n = (n+1) % 16;
  82                 }
  83 #ifdef __STRICT_ALIGNMENT
  84                 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
  85                         break;
  86 #endif
  87                 while (len>=16) {
  88                         (*block)(ivec, ivec, key);
  89                         for (; n<16; n+=sizeof(size_t))
  90                                 *(size_t*)(out+n) =
  91                                 *(size_t*)(in+n) ^ *(size_t*)(ivec+n);
  92                         len -= 16;
  93                         out += 16;
  94                         in  += 16;
  95                         n = 0;
  96                 }
  97                 if (len) {
  98                         (*block)(ivec, ivec, key);
  99                         while (len--) {
 100                                 out[n] = in[n] ^ ivec[n];
 101                                 ++n;
 102                         }
 103                 }
 104                 *num = n;
 105                 return;
 106         } while(0);
 107         /* the rest would be commonly eliminated by x86* compiler */
 108 #endif
 109         while (l<len) {
 110                 if (n==0) {
 111                         (*block)(ivec, ivec, key);
 112                 }
 113                 out[l] = in[l] ^ ivec[n];
 114                 ++l;
 115                 n = (n+1) % 16;
 116         }
 117
 118         *num=n;
 119 }