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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/* The input and output encrypted as though 128bit cfb 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 */
66void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
67 size_t len, const void *key,
68 unsigned char ivec[16], int *num,
69 int enc, 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 (enc) {
79#if !defined(OPENSSL_SMALL_FOOTPRINT)
80 if (16%sizeof(size_t) == 0) do { /* always true actually */
81 while (n && len) {
82 *(out++) = ivec[n] ^= *(in++);
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) != 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*)(ivec+n) ^= *(size_t*)(in+n);
95 }
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] = ivec[n] ^= in[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] = ivec[n] ^= in[l];
118 ++l;
119 n = (n+1) % 16;
120 }
121 *num = n;
122 } else {
123#if !defined(OPENSSL_SMALL_FOOTPRINT)
124 if (16%sizeof(size_t) == 0) do { /* always true actually */
125 while (n && len) {
126 unsigned char c;
127 *(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c;
128 --len;
129 n = (n+1) % 16;
130 }
131#if defined(STRICT_ALIGNMENT)
132 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
133 break;
134#endif
135 while (len>=16) {
136 (*block)(ivec, ivec, key);
137 for (; n<16; n+=sizeof(size_t)) {
138 size_t t = *(size_t*)(in+n);
139 *(size_t*)(out+n) = *(size_t*)(ivec+n) ^ t;
140 *(size_t*)(ivec+n) = t;
141 }
142 len -= 16;
143 out += 16;
144 in += 16;
145 n = 0;
146 }
147 if (len) {
148 (*block)(ivec, ivec, key);
149 while (len--) {
150 unsigned char c;
151 out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c;
152 ++n;
153 }
154 }
155 *num = n;
156 return;
157 } while (0);
158 /* the rest would be commonly eliminated by x86* compiler */
159#endif
160 while (l<len) {
161 unsigned char c;
162 if (n == 0) {
163 (*block)(ivec, ivec, key);
164 }
165 out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;
166 ++l;
167 n = (n+1) % 16;
168 }
169 *num=n;
170 }
171}
172
173/* This expects a single block of size nbits for both in and out. Note that
174 it corrupts any extra bits in the last byte of out */
175static void cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
176 int nbits,const void *key,
177 unsigned char ivec[16],int enc,
178 block128_f block)
179{
180 int n,rem,num;
181 unsigned char ovec[16*2 + 1]; /* +1 because we dererefence (but don't use) one byte off the end */
182
183 if (nbits<=0 || nbits>128) return;
184
185 /* fill in the first half of the new IV with the current IV */
186 memcpy(ovec,ivec,16);
187 /* construct the new IV */
188 (*block)(ivec,ivec,key);
189 num = (nbits+7)/8;
190 if (enc) /* encrypt the input */
191 for(n=0 ; n < num ; ++n)
192 out[n] = (ovec[16+n] = in[n] ^ ivec[n]);
193 else /* decrypt the input */
194 for(n=0 ; n < num ; ++n)
195 out[n] = (ovec[16+n] = in[n]) ^ ivec[n];
196 /* shift ovec left... */
197 rem = nbits%8;
198 num = nbits/8;
199 if(rem==0)
200 memcpy(ivec,ovec+num,16);
201 else
202 for(n=0 ; n < 16 ; ++n)
203 ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem);
204
205 /* it is not necessary to cleanse ovec, since the IV is not secret */
206}
207
208/* N.B. This expects the input to be packed, MS bit first */
209void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
210 size_t bits, const void *key,
211 unsigned char ivec[16], int *num,
212 int enc, block128_f block)
213{
214 size_t n;
215 unsigned char c[1],d[1];
216
217 assert(in && out && key && ivec && num);
218 assert(*num == 0);
219
220 for(n=0 ; n<bits ; ++n)
221 {
222 c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0;
223 cfbr_encrypt_block(c,d,1,key,ivec,enc,block);
224 out[n/8]=(out[n/8]&~(1 << (unsigned int)(7-n%8))) |
225 ((d[0]&0x80) >> (unsigned int)(n%8));
226 }
227}
228
229void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
230 size_t length, const void *key,
231 unsigned char ivec[16], int *num,
232 int enc, block128_f block)
233{
234 size_t n;
235
236 assert(in && out && key && ivec && num);
237 assert(*num == 0);
238
239 for(n=0 ; n<length ; ++n)
240 cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc,block);
241}
242
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