1 /* $OpenBSD: ofb128.c,v 1.7 2023/07/08 14:56:54 beck 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_local.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,size_t len,const void * key,unsigned char ivec[16],int * num,block128_f block)67 CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
68 size_t len, const void *key,
69 unsigned char ivec[16], int *num,
70 block128_f block)
71 {
72 unsigned int n;
73 size_t l = 0;
74
75 n = *num;
76
77 #if !defined(OPENSSL_SMALL_FOOTPRINT)
78 if (16 % sizeof(size_t) == 0)
79 do { /* always true actually */
80 while (n && len) {
81 *(out++) = *(in++) ^ ivec[n];
82 --len;
83 n = (n + 1) % 16;
84 }
85 #ifdef __STRICT_ALIGNMENT
86 if (((size_t)in|(size_t)out|(size_t)ivec) %
87 sizeof(size_t) != 0)
88 break;
89 #endif
90 while (len >= 16) {
91 (*block)(ivec, ivec, key);
92 for (; n < 16; n += sizeof(size_t))
93 *(size_t *)(out + n) =
94 *(size_t *)(in + n) ^ *(size_t *)(ivec +
95 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 /* the rest would be commonly eliminated by x86* compiler */
112 #endif
113 while (l < len) {
114 if (n == 0) {
115 (*block)(ivec, ivec, key);
116 }
117 out[l] = in[l] ^ ivec[n];
118 ++l;
119 n = (n + 1) % 16;
120 }
121
122 *num = n;
123 }
124 LCRYPTO_ALIAS(CRYPTO_ofb128_encrypt);
125