1 /* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * openssl-core@openssl.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 */
50
51 #include <openssl/crypto.h>
52 #include "modes_lcl.h"
53 #include <string.h>
54
55 #ifndef MODES_DEBUG
56 # ifndef NDEBUG
57 # define NDEBUG
58 # endif
59 #endif
60 #include <assert.h>
61
62 /*
63 * The input and output encrypted as though 128bit ofb mode is being used.
64 * The extra state information to record how much of the 128bit block we have
65 * used is contained in *num;
66 */
CRYPTO_ofb128_encrypt(const unsigned char * in,unsigned char * out,size_t len,const void * key,unsigned char ivec[16],int * num,block128_f block)67 void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
68 size_t len, const void *key,
69 unsigned char ivec[16], int *num, block128_f block)
70 {
71 unsigned int n;
72 size_t l = 0;
73
74 assert(in && out && key && ivec && num);
75
76 n = *num;
77
78 #if !defined(OPENSSL_SMALL_FOOTPRINT)
79 if (16 % sizeof(size_t) == 0) { /* always true actually */
80 do {
81 while (n && len) {
82 *(out++) = *(in++) ^ ivec[n];
83 --len;
84 n = (n + 1) % 16;
85 }
86 # if defined(STRICT_ALIGNMENT)
87 if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) !=
88 0)
89 break;
90 # endif
91 while (len >= 16) {
92 (*block) (ivec, ivec, key);
93 for (; n < 16; n += sizeof(size_t))
94 *(size_t *)(out + n) =
95 *(size_t *)(in + n) ^ *(size_t *)(ivec + n);
96 len -= 16;
97 out += 16;
98 in += 16;
99 n = 0;
100 }
101 if (len) {
102 (*block) (ivec, ivec, key);
103 while (len--) {
104 out[n] = in[n] ^ ivec[n];
105 ++n;
106 }
107 }
108 *num = n;
109 return;
110 } while (0);
111 }
112 /* the rest would be commonly eliminated by x86* compiler */
113 #endif
114 while (l < len) {
115 if (n == 0) {
116 (*block) (ivec, ivec, key);
117 }
118 out[l] = in[l] ^ ivec[n];
119 ++l;
120 n = (n + 1) % 16;
121 }
122
123 *num = n;
124 }
125