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 typedef unsigned int u32; 62 typedef unsigned char u8; 63 64 # define GETU32(pt) (((u32)(pt)[0] << 24) ^ ((u32)(pt)[1] << 16) ^ ((u32)(pt)[2] << 8) ^ ((u32)(pt)[3])) 65 # define PUTU32(ct, st) { (ct)[0] = (u8)((st) >> 24); (ct)[1] = (u8)((st) >> 16); (ct)[2] = (u8)((st) >> 8); (ct)[3] = (u8)(st); } 66 67 #define STRICT_ALIGNMENT 68 #if defined(__i386) || defined(__i386__) || \ 69 defined(__x86_64) || defined(__x86_64__) || \ 70 defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \ 71 defined(__s390__) || defined(__s390x__) 72 # undef STRICT_ALIGNMENT 73 #endif 74 75 /* NOTE: the IV/counter CTR mode is big-endian. The code itself 76 * is endian-neutral. */ 77 78 /* increment counter (128-bit int) by 1 */ 79 static void ctr128_inc(unsigned char *counter) { 80 u32 c,n=16; 81 82 do { 83 n -= 4; 84 c = GETU32(counter+n); 85 ++c; c &= 0xFFFFFFFF; 86 PUTU32(counter + n, c); 87 if (c) return; 88 } while (n); 89 } 90 91 #if !defined(OPENSSL_SMALL_FOORPRINT) 92 static void ctr128_inc_aligned(unsigned char *counter) { 93 size_t *data,c,n; 94 const union { long one; char little; } is_endian = {1}; 95 96 if (is_endian.little) { 97 ctr128_inc(counter); 98 return; 99 } 100 101 data = (size_t *)counter; 102 n = 16/sizeof(size_t); 103 do { 104 --n; 105 c = data[n]; 106 ++c; 107 data[n] = c; 108 if (c) return; 109 } while (n); 110 } 111 #endif 112 113 /* The input encrypted as though 128bit counter mode is being 114 * used. The extra state information to record how much of the 115 * 128bit block we have used is contained in *num, and the 116 * encrypted counter is kept in ecount_buf. Both *num and 117 * ecount_buf must be initialised with zeros before the first 118 * call to CRYPTO_ctr128_encrypt(). 119 * 120 * This algorithm assumes that the counter is in the x lower bits 121 * of the IV (ivec), and that the application has full control over 122 * overflow and the rest of the IV. This implementation takes NO 123 * responsability for checking that the counter doesn't overflow 124 * into the rest of the IV when incremented. 125 */ 126 void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out, 127 size_t len, const void *key, 128 unsigned char ivec[16], unsigned char ecount_buf[16], 129 unsigned int *num, block128_f block) 130 { 131 unsigned int n; 132 size_t l=0; 133 134 assert(in && out && key && ecount_buf && num); 135 assert(*num < 16); 136 137 n = *num; 138 139 #if !defined(OPENSSL_SMALL_FOOTPRINT) 140 if (16%sizeof(size_t) == 0) do { /* always true actually */ 141 while (n && len) { 142 *(out++) = *(in++) ^ ecount_buf[n]; 143 --len; 144 n = (n+1) % 16; 145 } 146 147 #if defined(STRICT_ALIGNMENT) 148 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) 149 break; 150 #endif 151 while (len>=16) { 152 (*block)(ivec, ecount_buf, key); 153 ctr128_inc_aligned(ivec); 154 for (n=0; n<16; n+=sizeof(size_t)) 155 *(size_t *)(out+n) = 156 *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n); 157 len -= 16; 158 out += 16; 159 in += 16; 160 } 161 n = 0; 162 if (len) { 163 (*block)(ivec, ecount_buf, key); 164 ctr128_inc_aligned(ivec); 165 while (len--) { 166 out[n] = in[n] ^ ecount_buf[n]; 167 ++n; 168 } 169 } 170 *num = n; 171 return; 172 } while(0); 173 /* the rest would be commonly eliminated by x86* compiler */ 174 #endif 175 while (l<len) { 176 if (n==0) { 177 (*block)(ivec, ecount_buf, key); 178 ctr128_inc(ivec); 179 } 180 out[l] = in[l] ^ ecount_buf[n]; 181 ++l; 182 n = (n+1) % 16; 183 } 184 185 *num=n; 186 } 187