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 (at) 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 #include <string.h> 53 54 #include "internal.h" 55 56 57 void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len, 58 const void *key, uint8_t ivec[16], int *num, int enc, 59 block128_f block) { 60 unsigned int n; 61 size_t l = 0; 62 63 assert(in && out && key && ivec && num); 64 assert((16 % sizeof(size_t)) == 0); 65 66 n = *num; 67 68 if (enc) { 69 while (n && len) { 70 *(out++) = ivec[n] ^= *(in++); 71 --len; 72 n = (n + 1) % 16; 73 } 74 #if STRICT_ALIGNMENT 75 if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { 76 while (l < len) { 77 if (n == 0) { 78 (*block)(ivec, ivec, key); 79 } 80 out[l] = ivec[n] ^= in[l]; 81 ++l; 82 n = (n + 1) % 16; 83 } 84 *num = n; 85 return; 86 } 87 #endif 88 while (len >= 16) { 89 (*block)(ivec, ivec, key); 90 for (; n < 16; n += sizeof(size_t)) { 91 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^= *(size_t *)(in + n); 92 } 93 len -= 16; 94 out += 16; 95 in += 16; 96 n = 0; 97 } 98 if (len) { 99 (*block)(ivec, ivec, key); 100 while (len--) { 101 out[n] = ivec[n] ^= in[n]; 102 ++n; 103 } 104 } 105 *num = n; 106 return; 107 } else { 108 while (n && len) { 109 uint8_t c; 110 *(out++) = ivec[n] ^ (c = *(in++)); 111 ivec[n] = c; 112 --len; 113 n = (n + 1) % 16; 114 } 115 if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { 116 while (l < len) { 117 unsigned char c; 118 if (n == 0) { 119 (*block)(ivec, ivec, key); 120 } 121 out[l] = ivec[n] ^ (c = in[l]); 122 ivec[n] = c; 123 ++l; 124 n = (n + 1) % 16; 125 } 126 *num = n; 127 return; 128 } 129 while (len >= 16) { 130 (*block)(ivec, ivec, key); 131 for (; n < 16; n += sizeof(size_t)) { 132 size_t t = *(size_t *)(in + n); 133 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t; 134 *(size_t *)(ivec + n) = t; 135 } 136 len -= 16; 137 out += 16; 138 in += 16; 139 n = 0; 140 } 141 if (len) { 142 (*block)(ivec, ivec, key); 143 while (len--) { 144 uint8_t c; 145 out[n] = ivec[n] ^ (c = in[n]); 146 ivec[n] = c; 147 ++n; 148 } 149 } 150 *num = n; 151 return; 152 } 153 } 154 155 156 /* This expects a single block of size nbits for both in and out. Note that 157 it corrupts any extra bits in the last byte of out */ 158 static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits, 159 const void *key, uint8_t ivec[16], int enc, 160 block128_f block) { 161 int n, rem, num; 162 uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one 163 byte off the end */ 164 165 if (nbits <= 0 || nbits > 128) { 166 return; 167 } 168 169 /* fill in the first half of the new IV with the current IV */ 170 memcpy(ovec, ivec, 16); 171 /* construct the new IV */ 172 (*block)(ivec, ivec, key); 173 num = (nbits + 7) / 8; 174 if (enc) { 175 /* encrypt the input */ 176 for (n = 0; n < num; ++n) { 177 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]); 178 } 179 } else { 180 /* decrypt the input */ 181 for (n = 0; n < num; ++n) { 182 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n]; 183 } 184 } 185 /* shift ovec left... */ 186 rem = nbits % 8; 187 num = nbits / 8; 188 if (rem == 0) { 189 memcpy(ivec, ovec + num, 16); 190 } else { 191 for (n = 0; n < 16; ++n) { 192 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem); 193 } 194 } 195 196 /* it is not necessary to cleanse ovec, since the IV is not secret */ 197 } 198 199 /* N.B. This expects the input to be packed, MS bit first */ 200 void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits, 201 const void *key, uint8_t ivec[16], int *num, 202 int enc, block128_f block) { 203 size_t n; 204 uint8_t c[1], d[1]; 205 206 assert(in && out && key && ivec && num); 207 assert(*num == 0); 208 209 for (n = 0; n < bits; ++n) { 210 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0; 211 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block); 212 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) | 213 ((d[0] & 0x80) >> (unsigned int)(n % 8)); 214 } 215 } 216 217 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, 218 size_t length, const void *key, 219 unsigned char ivec[16], int *num, int enc, 220 block128_f block) { 221 size_t n; 222 223 assert(in && out && key && ivec && num); 224 assert(*num == 0); 225 226 for (n = 0; n < length; ++n) { 227 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); 228 } 229 } 230 231
