Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 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 | |
Alexandre Savard | 7541067 | 2012-08-08 09:50:01 -0400 | [diff] [blame] | 51 | #include "modes.h" |
Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 52 | #include <string.h> |
| 53 | |
| 54 | #ifndef MODES_DEBUG |
| 55 | # ifndef NDEBUG |
| 56 | # define NDEBUG |
| 57 | # endif |
| 58 | #endif |
| 59 | #include <assert.h> |
| 60 | |
Alexandre Savard | 7541067 | 2012-08-08 09:50:01 -0400 | [diff] [blame] | 61 | typedef unsigned int u32; |
| 62 | typedef unsigned char u8; |
| 63 | |
| 64 | #define STRICT_ALIGNMENT |
| 65 | #if defined(__i386) || defined(__i386__) || \ |
| 66 | defined(__x86_64) || defined(__x86_64__) || \ |
| 67 | defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \ |
| 68 | defined(__s390__) || defined(__s390x__) |
| 69 | # undef STRICT_ALIGNMENT |
| 70 | #endif |
| 71 | |
Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 72 | /* NOTE: the IV/counter CTR mode is big-endian. The code itself |
| 73 | * is endian-neutral. */ |
| 74 | |
| 75 | /* increment counter (128-bit int) by 1 */ |
| 76 | static void ctr128_inc(unsigned char *counter) { |
| 77 | u32 n=16; |
| 78 | u8 c; |
| 79 | |
| 80 | do { |
| 81 | --n; |
| 82 | c = counter[n]; |
| 83 | ++c; |
| 84 | counter[n] = c; |
| 85 | if (c) return; |
| 86 | } while (n); |
| 87 | } |
| 88 | |
| 89 | #if !defined(OPENSSL_SMALL_FOOTPRINT) |
| 90 | static void ctr128_inc_aligned(unsigned char *counter) { |
| 91 | size_t *data,c,n; |
| 92 | const union { long one; char little; } is_endian = {1}; |
| 93 | |
| 94 | if (is_endian.little) { |
| 95 | ctr128_inc(counter); |
| 96 | return; |
| 97 | } |
| 98 | |
| 99 | data = (size_t *)counter; |
| 100 | n = 16/sizeof(size_t); |
| 101 | do { |
| 102 | --n; |
| 103 | c = data[n]; |
| 104 | ++c; |
| 105 | data[n] = c; |
| 106 | if (c) return; |
| 107 | } while (n); |
| 108 | } |
| 109 | #endif |
| 110 | |
| 111 | /* The input encrypted as though 128bit counter mode is being |
| 112 | * used. The extra state information to record how much of the |
| 113 | * 128bit block we have used is contained in *num, and the |
| 114 | * encrypted counter is kept in ecount_buf. Both *num and |
| 115 | * ecount_buf must be initialised with zeros before the first |
| 116 | * call to CRYPTO_ctr128_encrypt(). |
| 117 | * |
| 118 | * This algorithm assumes that the counter is in the x lower bits |
| 119 | * of the IV (ivec), and that the application has full control over |
| 120 | * overflow and the rest of the IV. This implementation takes NO |
| 121 | * responsability for checking that the counter doesn't overflow |
| 122 | * into the rest of the IV when incremented. |
| 123 | */ |
| 124 | void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out, |
| 125 | size_t len, const void *key, |
| 126 | unsigned char ivec[16], unsigned char ecount_buf[16], |
| 127 | unsigned int *num, block128_f block) |
| 128 | { |
| 129 | unsigned int n; |
| 130 | size_t l=0; |
| 131 | |
| 132 | assert(in && out && key && ecount_buf && num); |
| 133 | assert(*num < 16); |
| 134 | |
| 135 | n = *num; |
| 136 | |
| 137 | #if !defined(OPENSSL_SMALL_FOOTPRINT) |
| 138 | if (16%sizeof(size_t) == 0) do { /* always true actually */ |
| 139 | while (n && len) { |
| 140 | *(out++) = *(in++) ^ ecount_buf[n]; |
| 141 | --len; |
| 142 | n = (n+1) % 16; |
| 143 | } |
| 144 | |
| 145 | #if defined(STRICT_ALIGNMENT) |
| 146 | if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) |
| 147 | break; |
| 148 | #endif |
| 149 | while (len>=16) { |
| 150 | (*block)(ivec, ecount_buf, key); |
| 151 | ctr128_inc_aligned(ivec); |
| 152 | for (; n<16; n+=sizeof(size_t)) |
| 153 | *(size_t *)(out+n) = |
| 154 | *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n); |
| 155 | len -= 16; |
| 156 | out += 16; |
| 157 | in += 16; |
| 158 | n = 0; |
| 159 | } |
| 160 | if (len) { |
| 161 | (*block)(ivec, ecount_buf, key); |
| 162 | ctr128_inc_aligned(ivec); |
| 163 | while (len--) { |
| 164 | out[n] = in[n] ^ ecount_buf[n]; |
| 165 | ++n; |
| 166 | } |
| 167 | } |
| 168 | *num = n; |
| 169 | return; |
| 170 | } while(0); |
| 171 | /* the rest would be commonly eliminated by x86* compiler */ |
| 172 | #endif |
| 173 | while (l<len) { |
| 174 | if (n==0) { |
| 175 | (*block)(ivec, ecount_buf, key); |
| 176 | ctr128_inc(ivec); |
| 177 | } |
| 178 | out[l] = in[l] ^ ecount_buf[n]; |
| 179 | ++l; |
| 180 | n = (n+1) % 16; |
| 181 | } |
| 182 | |
| 183 | *num=n; |
| 184 | } |