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/type_check.h> 50 51 #include <assert.h> 52 #include <string.h> 53 54 #include "internal.h" 55 56 57 OPENSSL_COMPILE_ASSERT((16 % sizeof(size_t)) == 0, bad_size_t_size_cfb); 58 59 void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len, 60 const void *key, uint8_t ivec[16], unsigned *num, 61 int enc, block128_f block) { 62 size_t l = 0; 63 64 assert(in && out && key && ivec && num); 65 66 unsigned 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 (((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) != 76 0) { 77 while (l < len) { 78 if (n == 0) { 79 (*block)(ivec, ivec, key); 80 } 81 out[l] = ivec[n] ^= in[l]; 82 ++l; 83 n = (n + 1) % 16; 84 } 85 *num = n; 86 return; 87 } 88 #endif 89 while (len >= 16) { 90 (*block)(ivec, ivec, key); 91 for (; n < 16; n += sizeof(size_t)) { 92 size_t tmp = load_word_le(ivec + n) ^ load_word_le(in + n); 93 store_word_le(ivec + n, tmp); 94 store_word_le(out + n, tmp); 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 } else { 111 while (n && len) { 112 uint8_t c; 113 *(out++) = ivec[n] ^ (c = *(in++)); 114 ivec[n] = c; 115 --len; 116 n = (n + 1) % 16; 117 } 118 if (STRICT_ALIGNMENT && 119 ((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) != 120 0) { 121 while (l < len) { 122 uint8_t c; 123 if (n == 0) { 124 (*block)(ivec, ivec, key); 125 } 126 out[l] = ivec[n] ^ (c = in[l]); 127 ivec[n] = c; 128 ++l; 129 n = (n + 1) % 16; 130 } 131 *num = n; 132 return; 133 } 134 while (len >= 16) { 135 (*block)(ivec, ivec, key); 136 for (; n < 16; n += sizeof(size_t)) { 137 size_t t = load_word_le(in + n); 138 store_word_le(out + n, load_word_le(ivec + n) ^ t); 139 store_word_le(ivec + n, t); 140 } 141 len -= 16; 142 out += 16; 143 in += 16; 144 n = 0; 145 } 146 if (len) { 147 (*block)(ivec, ivec, key); 148 while (len--) { 149 uint8_t c; 150 out[n] = ivec[n] ^ (c = in[n]); 151 ivec[n] = c; 152 ++n; 153 } 154 } 155 *num = n; 156 return; 157 } 158 } 159 160 161 /* This expects a single block of size nbits for both in and out. Note that 162 it corrupts any extra bits in the last byte of out */ 163 static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits, 164 const void *key, uint8_t ivec[16], int enc, 165 block128_f block) { 166 int n, rem, num; 167 uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one 168 byte off the end */ 169 170 if (nbits <= 0 || nbits > 128) { 171 return; 172 } 173 174 // fill in the first half of the new IV with the current IV 175 OPENSSL_memcpy(ovec, ivec, 16); 176 // construct the new IV 177 (*block)(ivec, ivec, key); 178 num = (nbits + 7) / 8; 179 if (enc) { 180 // encrypt the input 181 for (n = 0; n < num; ++n) { 182 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]); 183 } 184 } else { 185 // decrypt the input 186 for (n = 0; n < num; ++n) { 187 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n]; 188 } 189 } 190 // shift ovec left... 191 rem = nbits % 8; 192 num = nbits / 8; 193 if (rem == 0) { 194 OPENSSL_memcpy(ivec, ovec + num, 16); 195 } else { 196 for (n = 0; n < 16; ++n) { 197 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem); 198 } 199 } 200 201 // it is not necessary to cleanse ovec, since the IV is not secret 202 } 203 204 // N.B. This expects the input to be packed, MS bit first 205 void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits, 206 const void *key, uint8_t ivec[16], unsigned *num, 207 int enc, block128_f block) { 208 size_t n; 209 uint8_t c[1], d[1]; 210 211 assert(in && out && key && ivec && num); 212 assert(*num == 0); 213 214 for (n = 0; n < bits; ++n) { 215 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0; 216 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block); 217 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) | 218 ((d[0] & 0x80) >> (unsigned int)(n % 8)); 219 } 220 } 221 222 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, 223 size_t length, const void *key, 224 unsigned char ivec[16], unsigned *num, int enc, 225 block128_f block) { 226 size_t n; 227 228 assert(in && out && key && ivec && num); 229 assert(*num == 0); 230 231 for (n = 0; n < length; ++n) { 232 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); 233 } 234 } 235
