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#include <openssl/modes.h> 50 51#include <assert.h> 52 53#include "internal.h" 54 55 56void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len, 57 const void *key, uint8_t ivec[16], int *num, int enc, 58 block128_f block) { 59 unsigned int n; 60 size_t l = 0; 61 62 assert(in && out && key && ivec && num); 63 assert((16 % sizeof(size_t)) == 0); 64 65 n = *num; 66 67 if (enc) { 68 while (n && len) { 69 *(out++) = ivec[n] ^= *(in++); 70 --len; 71 n = (n + 1) % 16; 72 } 73 if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { 74 while (l < len) { 75 if (n == 0) { 76 (*block)(ivec, ivec, key); 77 } 78 out[l] = ivec[n] ^= in[l]; 79 ++l; 80 n = (n + 1) % 16; 81 } 82 *num = n; 83 return; 84 } 85 while (len >= 16) { 86 (*block)(ivec, ivec, key); 87 for (; n < 16; n += sizeof(size_t)) { 88 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^= *(size_t *)(in + n); 89 } 90 len -= 16; 91 out += 16; 92 in += 16; 93 n = 0; 94 } 95 if (len) { 96 (*block)(ivec, ivec, key); 97 while (len--) { 98 out[n] = ivec[n] ^= in[n]; 99 ++n; 100 } 101 } 102 *num = n; 103 return; 104 } else { 105 while (n && len) { 106 uint8_t c; 107 *(out++) = ivec[n] ^ (c = *(in++)); 108 ivec[n] = c; 109 --len; 110 n = (n + 1) % 16; 111 } 112 if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { 113 while (l < len) { 114 unsigned char c; 115 if (n == 0) { 116 (*block)(ivec, ivec, key); 117 } 118 out[l] = ivec[n] ^ (c = in[l]); 119 ivec[n] = c; 120 ++l; 121 n = (n + 1) % 16; 122 } 123 *num = n; 124 return; 125 } 126 while (len >= 16) { 127 (*block)(ivec, ivec, key); 128 for (; n < 16; n += sizeof(size_t)) { 129 size_t t = *(size_t *)(in + n); 130 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t; 131 *(size_t *)(ivec + n) = t; 132 } 133 len -= 16; 134 out += 16; 135 in += 16; 136 n = 0; 137 } 138 if (len) { 139 (*block)(ivec, ivec, key); 140 while (len--) { 141 uint8_t c; 142 out[n] = ivec[n] ^ (c = in[n]); 143 ivec[n] = c; 144 ++n; 145 } 146 } 147 *num = n; 148 return; 149 } 150} 151 152 153/* This expects a single block of size nbits for both in and out. Note that 154 it corrupts any extra bits in the last byte of out */ 155static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits, 156 const void *key, uint8_t ivec[16], int enc, 157 block128_f block) { 158 int n, rem, num; 159 uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one 160 byte off the end */ 161 162 if (nbits <= 0 || nbits > 128) { 163 return; 164 } 165 166 /* fill in the first half of the new IV with the current IV */ 167 memcpy(ovec, ivec, 16); 168 /* construct the new IV */ 169 (*block)(ivec, ivec, key); 170 num = (nbits + 7) / 8; 171 if (enc) { 172 /* encrypt the input */ 173 for (n = 0; n < num; ++n) { 174 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]); 175 } 176 } else { 177 /* decrypt the input */ 178 for (n = 0; n < num; ++n) { 179 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n]; 180 } 181 } 182 /* shift ovec left... */ 183 rem = nbits % 8; 184 num = nbits / 8; 185 if (rem == 0) { 186 memcpy(ivec, ovec + num, 16); 187 } else { 188 for (n = 0; n < 16; ++n) { 189 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem); 190 } 191 } 192 193 /* it is not necessary to cleanse ovec, since the IV is not secret */ 194} 195 196/* N.B. This expects the input to be packed, MS bit first */ 197void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits, 198 const void *key, uint8_t ivec[16], int *num, 199 int enc, block128_f block) { 200 size_t n; 201 uint8_t c[1], d[1]; 202 203 assert(in && out && key && ivec && num); 204 assert(*num == 0); 205 206 for (n = 0; n < bits; ++n) { 207 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0; 208 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block); 209 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) | 210 ((d[0] & 0x80) >> (unsigned int)(n % 8)); 211 } 212} 213 214void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, 215 size_t length, const void *key, 216 unsigned char ivec[16], int *num, int enc, 217 block128_f block) { 218 size_t n; 219 220 assert(in && out && key && ivec && num); 221 assert(*num == 0); 222 223 for (n = 0; n < length; ++n) { 224 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); 225 } 226} 227 228