lib/libcrypto/aes/aes_wrap.c

   1 /* $OpenBSD: aes_wrap.c,v 1.10 2015/09/10 15:56:24 jsing Exp $ */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  */
  53
  54 #include <string.h>
  55
  56 #include <openssl/aes.h>
  57 #include <openssl/bio.h>
  58
  59 static const unsigned char default_iv[] = {
  60         0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6,
  61 };
  62
  63 int
  64 AES_wrap_key(AES_KEY *key, const unsigned char *iv, unsigned char *out,
  65     const unsigned char *in, unsigned int inlen)
  66 {
  67         unsigned char *A, B[16], *R;
  68         unsigned int i, j, t;
  69         if ((inlen & 0x7) || (inlen < 8))
  70                 return -1;
  71         A = B;
  72         t = 1;
  73         memcpy(out + 8, in, inlen);
  74         if (!iv)
  75                 iv = default_iv;
  76
  77         memcpy(A, iv, 8);
  78
  79         for (j = 0; j < 6; j++) {
  80                 R = out + 8;
  81                 for (i = 0; i < inlen; i += 8, t++, R += 8) {
  82                         memcpy(B + 8, R, 8);
  83                         AES_encrypt(B, B, key);
  84                         A[7] ^= (unsigned char)(t & 0xff);
  85                         if (t > 0xff) {
  86                                 A[6] ^= (unsigned char)((t >> 8) & 0xff);
  87                                 A[5] ^= (unsigned char)((t >> 16) & 0xff);
  88                                 A[4] ^= (unsigned char)((t >> 24) & 0xff);
  89                         }
  90                         memcpy(R, B + 8, 8);
  91                 }
  92         }
  93         memcpy(out, A, 8);
  94         return inlen + 8;
  95 }
  96
  97 int
  98 AES_unwrap_key(AES_KEY *key, const unsigned char *iv, unsigned char *out,
  99     const unsigned char *in, unsigned int inlen)
 100 {
 101         unsigned char *A, B[16], *R;
 102         unsigned int i, j, t;
 103         inlen -= 8;
 104         if (inlen & 0x7)
 105                 return -1;
 106         if (inlen < 8)
 107                 return -1;
 108         A = B;
 109         t = 6 * (inlen >> 3);
 110         memcpy(A, in, 8);
 111         memcpy(out, in + 8, inlen);
 112         for (j = 0; j < 6; j++) {
 113                 R = out + inlen - 8;
 114                 for (i = 0; i < inlen; i += 8, t--, R -= 8) {
 115                         A[7] ^= (unsigned char)(t & 0xff);
 116                         if (t > 0xff) {
 117                                 A[6] ^= (unsigned char)((t >> 8) & 0xff);
 118                                 A[5] ^= (unsigned char)((t >> 16) & 0xff);
 119                                 A[4] ^= (unsigned char)((t >> 24) & 0xff);
 120                         }
 121                         memcpy(B + 8, R, 8);
 122                         AES_decrypt(B, B, key);
 123                         memcpy(R, B + 8, 8);
 124                 }
 125         }
 126         if (!iv)
 127                 iv = default_iv;
 128         if (memcmp(A, iv, 8)) {
 129                 explicit_bzero(out, inlen);
 130                 return 0;
 131         }
 132         return inlen;
 133 }