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 */ 50 51 #include <openssl/crypto.h> 52 #include "modes_lcl.h" 53 #include <string.h> 54 55 #ifndef MODES_DEBUG 56 # ifndef NDEBUG 57 # define NDEBUG 58 # endif 59 #endif 60 #include <assert.h> 61 62 /* The input and output encrypted as though 128bit cfb mode is being 63 * used. The extra state information to record how much of the 64 * 128bit block we have used is contained in *num; 65 */ 66 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out, 67 size_t len, const void *key, 68 unsigned char ivec[16], int *num, 69 int enc, block128_f block) 70 { 71 unsigned int n; 72 size_t l = 0; 73 74 assert(in && out && key && ivec && num); 75 76 n = *num; 77 78 if (enc) { 79 #if !defined(OPENSSL_SMALL_FOOTPRINT) 80 if (16%sizeof(size_t) == 0) do { /* always true actually */ 81 while (n && len) { 82 *(out++) = ivec[n] ^= *(in++); 83 --len; 84 n = (n+1) % 16; 85 } 86 #if defined(STRICT_ALIGNMENT) 87 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) 88 break; 89 #endif 90 while (len>=16) { 91 (*block)(ivec, ivec, key); 92 for (; n<16; n+=sizeof(size_t)) { 93 *(size_t*)(out+n) = 94 *(size_t*)(ivec+n) ^= *(size_t*)(in+n); 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 } while (0); 111 /* the rest would be commonly eliminated by x86* compiler */ 112 #endif 113 while (l<len) { 114 if (n == 0) { 115 (*block)(ivec, ivec, key); 116 } 117 out[l] = ivec[n] ^= in[l]; 118 ++l; 119 n = (n+1) % 16; 120 } 121 *num = n; 122 } else { 123 #if !defined(OPENSSL_SMALL_FOOTPRINT) 124 if (16%sizeof(size_t) == 0) do { /* always true actually */ 125 while (n && len) { 126 unsigned char c; 127 *(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c; 128 --len; 129 n = (n+1) % 16; 130 } 131 #if defined(STRICT_ALIGNMENT) 132 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) 133 break; 134 #endif 135 while (len>=16) { 136 (*block)(ivec, ivec, key); 137 for (; n<16; n+=sizeof(size_t)) { 138 size_t t = *(size_t*)(in+n); 139 *(size_t*)(out+n) = *(size_t*)(ivec+n) ^ t; 140 *(size_t*)(ivec+n) = t; 141 } 142 len -= 16; 143 out += 16; 144 in += 16; 145 n = 0; 146 } 147 if (len) { 148 (*block)(ivec, ivec, key); 149 while (len--) { 150 unsigned char c; 151 out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c; 152 ++n; 153 } 154 } 155 *num = n; 156 return; 157 } while (0); 158 /* the rest would be commonly eliminated by x86* compiler */ 159 #endif 160 while (l<len) { 161 unsigned char c; 162 if (n == 0) { 163 (*block)(ivec, ivec, key); 164 } 165 out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c; 166 ++l; 167 n = (n+1) % 16; 168 } 169 *num=n; 170 } 171 } 172 173 /* This expects a single block of size nbits for both in and out. Note that 174 it corrupts any extra bits in the last byte of out */ 175 static void cfbr_encrypt_block(const unsigned char *in,unsigned char *out, 176 int nbits,const void *key, 177 unsigned char ivec[16],int enc, 178 block128_f block) 179 { 180 int n,rem,num; 181 unsigned char ovec[16*2 + 1]; /* +1 because we dererefence (but don't use) one byte off the end */ 182 183 if (nbits<=0 || nbits>128) return; 184 185 /* fill in the first half of the new IV with the current IV */ 186 memcpy(ovec,ivec,16); 187 /* construct the new IV */ 188 (*block)(ivec,ivec,key); 189 num = (nbits+7)/8; 190 if (enc) /* encrypt the input */ 191 for(n=0 ; n < num ; ++n) 192 out[n] = (ovec[16+n] = in[n] ^ ivec[n]); 193 else /* decrypt the input */ 194 for(n=0 ; n < num ; ++n) 195 out[n] = (ovec[16+n] = in[n]) ^ ivec[n]; 196 /* shift ovec left... */ 197 rem = nbits%8; 198 num = nbits/8; 199 if(rem==0) 200 memcpy(ivec,ovec+num,16); 201 else 202 for(n=0 ; n < 16 ; ++n) 203 ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem); 204 205 /* it is not necessary to cleanse ovec, since the IV is not secret */ 206 } 207 208 /* N.B. This expects the input to be packed, MS bit first */ 209 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out, 210 size_t bits, const void *key, 211 unsigned char ivec[16], int *num, 212 int enc, block128_f block) 213 { 214 size_t n; 215 unsigned char c[1],d[1]; 216 217 assert(in && out && key && ivec && num); 218 assert(*num == 0); 219 220 for(n=0 ; n<bits ; ++n) 221 { 222 c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0; 223 cfbr_encrypt_block(c,d,1,key,ivec,enc,block); 224 out[n/8]=(out[n/8]&~(1 << (unsigned int)(7-n%8))) | 225 ((d[0]&0x80) >> (unsigned int)(n%8)); 226 } 227 } 228 229 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, 230 size_t length, const void *key, 231 unsigned char ivec[16], int *num, 232 int enc, block128_f block) 233 { 234 size_t n; 235 236 assert(in && out && key && ivec && num); 237 assert(*num == 0); 238 239 for(n=0 ; n<length ; ++n) 240 cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc,block); 241 } 242 243
