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 */ 50 51 #include "modes.h" 52 #include <string.h> 53 54 #ifndef MODES_DEBUG 55 # ifndef NDEBUG 56 # define NDEBUG 57 # endif 58 #endif 59 #include <assert.h> 60 61 #define STRICT_ALIGNMENT 62 #if defined(__i386) || defined(__i386__) || \ 63 defined(__x86_64) || defined(__x86_64__) || \ 64 defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \ 65 defined(__s390__) || defined(__s390x__) 66 # undef STRICT_ALIGNMENT 67 #endif 68 69 /* The input and output encrypted as though 128bit cfb mode is being 70 * used. The extra state information to record how much of the 71 * 128bit block we have used is contained in *num; 72 */ 73 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out, 74 size_t len, const void *key, 75 unsigned char ivec[16], int *num, 76 int enc, block128_f block) 77 { 78 unsigned int n; 79 size_t l = 0; 80 81 assert(in && out && key && ivec && num); 82 83 n = *num; 84 85 if (enc) { 86 #if !defined(OPENSSL_SMALL_FOOTPRINT) 87 if (16%sizeof(size_t) == 0) do { /* always true actually */ 88 while (n && len) { 89 *(out++) = ivec[n] ^= *(in++); 90 --len; 91 n = (n+1) % 16; 92 } 93 #if defined(STRICT_ALIGNMENT) 94 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) 95 break; 96 #endif 97 while (len>=16) { 98 (*block)(ivec, ivec, key); 99 for (n=0; n<16; n+=sizeof(size_t)) { 100 *(size_t*)(out+n) = 101 *(size_t*)(ivec+n) ^= *(size_t*)(in+n); 102 } 103 len -= 16; 104 out += 16; 105 in += 16; 106 } 107 n = 0; 108 if (len) { 109 (*block)(ivec, ivec, key); 110 while (len--) { 111 out[n] = ivec[n] ^= in[n]; 112 ++n; 113 } 114 } 115 *num = n; 116 return; 117 } while (0); 118 /* the rest would be commonly eliminated by x86* compiler */ 119 #endif 120 while (l<len) { 121 if (n == 0) { 122 (*block)(ivec, ivec, key); 123 } 124 out[l] = ivec[n] ^= in[l]; 125 ++l; 126 n = (n+1) % 16; 127 } 128 *num = n; 129 } else { 130 #if !defined(OPENSSL_SMALL_FOOTPRINT) 131 if (16%sizeof(size_t) == 0) do { /* always true actually */ 132 while (n && len) { 133 unsigned char c; 134 *(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c; 135 --len; 136 n = (n+1) % 16; 137 } 138 #if defined(STRICT_ALIGNMENT) 139 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) 140 break; 141 #endif 142 while (len>=16) { 143 (*block)(ivec, ivec, key); 144 for (n=0; n<16; n+=sizeof(size_t)) { 145 size_t t = *(size_t*)(in+n); 146 *(size_t*)(out+n) = *(size_t*)(ivec+n) ^ t; 147 *(size_t*)(ivec+n) = t; 148 } 149 len -= 16; 150 out += 16; 151 in += 16; 152 } 153 n = 0; 154 if (len) { 155 (*block)(ivec, ivec, key); 156 while (len--) { 157 unsigned char c; 158 out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c; 159 ++n; 160 } 161 } 162 *num = n; 163 return; 164 } while (0); 165 /* the rest would be commonly eliminated by x86* compiler */ 166 #endif 167 while (l<len) { 168 unsigned char c; 169 if (n == 0) { 170 (*block)(ivec, ivec, key); 171 } 172 out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c; 173 ++l; 174 n = (n+1) % 16; 175 } 176 *num=n; 177 } 178 } 179 180 /* This expects a single block of size nbits for both in and out. Note that 181 it corrupts any extra bits in the last byte of out */ 182 static void cfbr_encrypt_block(const unsigned char *in,unsigned char *out, 183 int nbits,const void *key, 184 unsigned char ivec[16],int enc, 185 block128_f block) 186 { 187 int n,rem,num; 188 unsigned char ovec[16*2 + 1]; /* +1 because we dererefence (but don't use) one byte off the end */ 189 190 if (nbits<=0 || nbits>128) return; 191 192 /* fill in the first half of the new IV with the current IV */ 193 memcpy(ovec,ivec,16); 194 /* construct the new IV */ 195 (*block)(ivec,ivec,key); 196 num = (nbits+7)/8; 197 if (enc) /* encrypt the input */ 198 for(n=0 ; n < num ; ++n) 199 out[n] = (ovec[16+n] = in[n] ^ ivec[n]); 200 else /* decrypt the input */ 201 for(n=0 ; n < num ; ++n) 202 out[n] = (ovec[16+n] = in[n]) ^ ivec[n]; 203 /* shift ovec left... */ 204 rem = nbits%8; 205 num = nbits/8; 206 if(rem==0) 207 memcpy(ivec,ovec+num,16); 208 else 209 for(n=0 ; n < 16 ; ++n) 210 ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem); 211 212 /* it is not necessary to cleanse ovec, since the IV is not secret */ 213 } 214 215 /* N.B. This expects the input to be packed, MS bit first */ 216 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out, 217 size_t bits, const void *key, 218 unsigned char ivec[16], int *num, 219 int enc, block128_f block) 220 { 221 size_t n; 222 unsigned char c[1],d[1]; 223 224 assert(in && out && key && ivec && num); 225 assert(*num == 0); 226 227 memset(out,0,(bits+7)/8); 228 for(n=0 ; n<bits ; ++n) 229 { 230 c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0; 231 cfbr_encrypt_block(c,d,1,key,ivec,enc,block); 232 out[n/8]=(out[n/8]&~(1 << (unsigned int)(7-n%8))) | 233 ((d[0]&0x80) >> (unsigned int)(n%8)); 234 } 235 } 236 237 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, 238 size_t length, const void *key, 239 unsigned char ivec[16], int *num, 240 int enc, block128_f block) 241 { 242 size_t n; 243 244 assert(in && out && key && ivec && num); 245 assert(*num == 0); 246 247 for(n=0 ; n<length ; ++n) 248 cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc,block); 249 } 250 251