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 "modes.h"
52#include <string.h>
53
54#ifndef MODES_DEBUG
55# ifndef NDEBUG
56#  define NDEBUG
57# endif
58#endif
59#include <assert.h>
60
61#define STRICT_ALIGNMENT
62#if defined(__i386) || defined(__i386__) || \
63    defined(__x86_64) || defined(__x86_64__) || \
64    defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \
65    defined(__s390__) || defined(__s390x__)
66#  undef STRICT_ALIGNMENT
67#endif
68
69/* The input and output encrypted as though 128bit ofb mode is being
70 * used.  The extra state information to record how much of the
71 * 128bit block we have used is contained in *num;
72 */
73void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
74			size_t len, const void *key,
75			unsigned char ivec[16], int *num,
76			block128_f block)
77{
78	unsigned int n;
79	size_t l=0;
80
81	assert(in && out && key && ivec && num);
82
83	n = *num;
84
85#if !defined(OPENSSL_SMALL_FOOTPRINT)
86	if (16%sizeof(size_t) == 0) do { /* always true actually */
87		while (n && len) {
88			*(out++) = *(in++) ^ ivec[n];
89			--len;
90			n = (n+1) % 16;
91		}
92#if defined(STRICT_ALIGNMENT)
93		if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
94			break;
95#endif
96		while (len>=16) {
97			(*block)(ivec, ivec, key);
98			for (; n<16; n+=sizeof(size_t))
99				*(size_t*)(out+n) =
100				*(size_t*)(in+n) ^ *(size_t*)(ivec+n);
101			len -= 16;
102			out += 16;
103			in  += 16;
104			n = 0;
105		}
106		if (len) {
107			(*block)(ivec, ivec, key);
108			while (len--) {
109				out[n] = in[n] ^ ivec[n];
110				++n;
111			}
112		}
113		*num = n;
114		return;
115	} while(0);
116	/* the rest would be commonly eliminated by x86* compiler */
117#endif
118	while (l<len) {
119		if (n==0) {
120			(*block)(ivec, ivec, key);
121		}
122		out[l] = in[l] ^ ivec[n];
123		++l;
124		n = (n+1) % 16;
125	}
126
127	*num=n;
128}
129