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); 58 59 void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len, 60 const void *key, uint8_t ivec[16], int *num, int enc, 61 block128_f block) { 62 unsigned int n; 63 size_t l = 0; 64 65 assert(in && out && key && ivec && num); 66 67 n = *num; 68 69 if (enc) { 70 while (n && len) { 71 *(out++) = ivec[n] ^= *(in++); 72 --len; 73 n = (n + 1) % 16; 74 } 75 #if STRICT_ALIGNMENT 76 if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 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 *)(out + n) = *(size_t *)(ivec + n) ^= *(size_t *)(in + n); 93 } 94 len -= 16; 95 out += 16; 96 in += 16; 97 n = 0; 98 } 99 if (len) { 100 (*block)(ivec, ivec, key); 101 while (len--) { 102 out[n] = ivec[n] ^= in[n]; 103 ++n; 104 } 105 } 106 *num = n; 107 return; 108 } else { 109 while (n && len) { 110 uint8_t c; 111 *(out++) = ivec[n] ^ (c = *(in++)); 112 ivec[n] = c; 113 --len; 114 n = (n + 1) % 16; 115 } 116 if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { 117 while (l < len) { 118 unsigned char c; 119 if (n == 0) { 120 (*block)(ivec, ivec, key); 121 } 122 out[l] = ivec[n] ^ (c = in[l]); 123 ivec[n] = c; 124 ++l; 125 n = (n + 1) % 16; 126 } 127 *num = n; 128 return; 129 } 130 while (len >= 16) { 131 (*block)(ivec, ivec, key); 132 for (; n < 16; n += sizeof(size_t)) { 133 size_t t = *(size_t *)(in + n); 134 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t; 135 *(size_t *)(ivec + n) = t; 136 } 137 len -= 16; 138 out += 16; 139 in += 16; 140 n = 0; 141 } 142 if (len) { 143 (*block)(ivec, ivec, key); 144 while (len--) { 145 uint8_t c; 146 out[n] = ivec[n] ^ (c = in[n]); 147 ivec[n] = c; 148 ++n; 149 } 150 } 151 *num = n; 152 return; 153 } 154 } 155 156 157 /* This expects a single block of size nbits for both in and out. Note that 158 it corrupts any extra bits in the last byte of out */ 159 static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits, 160 const void *key, uint8_t ivec[16], int enc, 161 block128_f block) { 162 int n, rem, num; 163 uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one 164 byte off the end */ 165 166 if (nbits <= 0 || nbits > 128) { 167 return; 168 } 169 170 /* fill in the first half of the new IV with the current IV */ 171 memcpy(ovec, ivec, 16); 172 /* construct the new IV */ 173 (*block)(ivec, ivec, key); 174 num = (nbits + 7) / 8; 175 if (enc) { 176 /* encrypt the input */ 177 for (n = 0; n < num; ++n) { 178 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]); 179 } 180 } else { 181 /* decrypt the input */ 182 for (n = 0; n < num; ++n) { 183 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n]; 184 } 185 } 186 /* shift ovec left... */ 187 rem = nbits % 8; 188 num = nbits / 8; 189 if (rem == 0) { 190 memcpy(ivec, ovec + num, 16); 191 } else { 192 for (n = 0; n < 16; ++n) { 193 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem); 194 } 195 } 196 197 /* it is not necessary to cleanse ovec, since the IV is not secret */ 198 } 199 200 /* N.B. This expects the input to be packed, MS bit first */ 201 void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits, 202 const void *key, uint8_t ivec[16], int *num, 203 int enc, block128_f block) { 204 size_t n; 205 uint8_t c[1], d[1]; 206 207 assert(in && out && key && ivec && num); 208 assert(*num == 0); 209 210 for (n = 0; n < bits; ++n) { 211 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0; 212 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block); 213 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) | 214 ((d[0] & 0x80) >> (unsigned int)(n % 8)); 215 } 216 } 217 218 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, 219 size_t length, const void *key, 220 unsigned char ivec[16], int *num, int enc, 221 block128_f block) { 222 size_t n; 223 224 assert(in && out && key && ivec && num); 225 assert(*num == 0); 226 227 for (n = 0; n < length; ++n) { 228 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); 229 } 230 } 231 232
