2 * Copyright 2008-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 #include <openssl/crypto.h>
12 #include "crypto/modes.h"
14 #if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
15 typedef size_t size_t_aX __attribute((__aligned__(1)));
17 typedef size_t size_t_aX;
21 * The input and output encrypted as though 128bit cfb mode is being used.
22 * The extra state information to record how much of the 128bit block we have
23 * used is contained in *num;
25 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
26 size_t len, const void *key,
27 unsigned char ivec[16], int *num,
28 int enc, block128_f block)
34 /* There is no good way to signal an error return from here */
41 #if !defined(OPENSSL_SMALL_FOOTPRINT)
42 if (16 % sizeof(size_t) == 0) { /* always true actually */
45 *(out++) = ivec[n] ^= *(in++);
49 # if defined(STRICT_ALIGNMENT)
50 if (((size_t)in | (size_t)out | (size_t)ivec) %
55 (*block) (ivec, ivec, key);
56 for (; n < 16; n += sizeof(size_t)) {
57 *(size_t_aX *)(out + n) =
58 *(size_t_aX *)(ivec + n)
59 ^= *(size_t_aX *)(in + n);
67 (*block) (ivec, ivec, key);
69 out[n] = ivec[n] ^= in[n];
77 /* the rest would be commonly eliminated by x86* compiler */
81 (*block) (ivec, ivec, key);
83 out[l] = ivec[n] ^= in[l];
89 #if !defined(OPENSSL_SMALL_FOOTPRINT)
90 if (16 % sizeof(size_t) == 0) { /* always true actually */
94 *(out++) = ivec[n] ^ (c = *(in++));
99 # if defined(STRICT_ALIGNMENT)
100 if (((size_t)in | (size_t)out | (size_t)ivec) %
105 (*block) (ivec, ivec, key);
106 for (; n < 16; n += sizeof(size_t)) {
107 size_t t = *(size_t_aX *)(in + n);
108 *(size_t_aX *)(out + n)
109 = *(size_t_aX *)(ivec + n) ^ t;
110 *(size_t_aX *)(ivec + n) = t;
118 (*block) (ivec, ivec, key);
121 out[n] = ivec[n] ^ (c = in[n]);
130 /* the rest would be commonly eliminated by x86* compiler */
135 (*block) (ivec, ivec, key);
137 out[l] = ivec[n] ^ (c = in[l]);
147 * This expects a single block of size nbits for both in and out. Note that
148 * it corrupts any extra bits in the last byte of out
150 static void cfbr_encrypt_block(const unsigned char *in, unsigned char *out,
151 int nbits, const void *key,
152 unsigned char ivec[16], int enc,
156 unsigned char ovec[16 * 2 + 1]; /* +1 because we dereference (but don't
157 * use) one byte off the end */
159 if (nbits <= 0 || nbits > 128)
162 /* fill in the first half of the new IV with the current IV */
163 memcpy(ovec, ivec, 16);
164 /* construct the new IV */
165 (*block) (ivec, ivec, key);
166 num = (nbits + 7) / 8;
167 if (enc) /* encrypt the input */
168 for (n = 0; n < num; ++n)
169 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
170 else /* decrypt the input */
171 for (n = 0; n < num; ++n)
172 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
173 /* shift ovec left... */
177 memcpy(ivec, ovec + num, 16);
179 for (n = 0; n < 16; ++n)
180 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
182 /* it is not necessary to cleanse ovec, since the IV is not secret */
185 /* N.B. This expects the input to be packed, MS bit first */
186 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
187 size_t bits, const void *key,
188 unsigned char ivec[16], int *num,
189 int enc, block128_f block)
192 unsigned char c[1], d[1];
194 for (n = 0; n < bits; ++n) {
195 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
196 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
197 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
198 ((d[0] & 0x80) >> (unsigned int)(n % 8));
202 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
203 size_t length, const void *key,
204 unsigned char ivec[16], int *num,
205 int enc, block128_f block)
209 for (n = 0; n < length; ++n)
210 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);