| /* ==================================================================== |
| * Copyright (c) 2008 The OpenSSL Project. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. All advertising materials mentioning features or use of this |
| * software must display the following acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
| * |
| * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
| * endorse or promote products derived from this software without |
| * prior written permission. For written permission, please contact |
| * openssl-core@openssl.org. |
| * |
| * 5. Products derived from this software may not be called "OpenSSL" |
| * nor may "OpenSSL" appear in their names without prior written |
| * permission of the OpenSSL Project. |
| * |
| * 6. Redistributions of any form whatsoever must retain the following |
| * acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
| * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * ==================================================================== |
| * |
| */ |
| |
| #include "modes.h" |
| #include <string.h> |
| |
| #ifndef MODES_DEBUG |
| # ifndef NDEBUG |
| # define NDEBUG |
| # endif |
| #endif |
| #include <assert.h> |
| |
| typedef unsigned int u32; |
| typedef unsigned char u8; |
| |
| #define STRICT_ALIGNMENT |
| #if defined(__i386) || defined(__i386__) || \ |
| defined(__x86_64) || defined(__x86_64__) || \ |
| defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \ |
| defined(__s390__) || defined(__s390x__) |
| # undef STRICT_ALIGNMENT |
| #endif |
| |
| /* NOTE: the IV/counter CTR mode is big-endian. The code itself |
| * is endian-neutral. */ |
| |
| /* increment counter (128-bit int) by 1 */ |
| static void ctr128_inc(unsigned char *counter) { |
| u32 n=16; |
| u8 c; |
| |
| do { |
| --n; |
| c = counter[n]; |
| ++c; |
| counter[n] = c; |
| if (c) return; |
| } while (n); |
| } |
| |
| #if !defined(OPENSSL_SMALL_FOOTPRINT) |
| static void ctr128_inc_aligned(unsigned char *counter) { |
| size_t *data,c,n; |
| const union { long one; char little; } is_endian = {1}; |
| |
| if (is_endian.little) { |
| ctr128_inc(counter); |
| return; |
| } |
| |
| data = (size_t *)counter; |
| n = 16/sizeof(size_t); |
| do { |
| --n; |
| c = data[n]; |
| ++c; |
| data[n] = c; |
| if (c) return; |
| } while (n); |
| } |
| #endif |
| |
| /* The input encrypted as though 128bit counter mode is being |
| * used. The extra state information to record how much of the |
| * 128bit block we have used is contained in *num, and the |
| * encrypted counter is kept in ecount_buf. Both *num and |
| * ecount_buf must be initialised with zeros before the first |
| * call to CRYPTO_ctr128_encrypt(). |
| * |
| * This algorithm assumes that the counter is in the x lower bits |
| * of the IV (ivec), and that the application has full control over |
| * overflow and the rest of the IV. This implementation takes NO |
| * responsability for checking that the counter doesn't overflow |
| * into the rest of the IV when incremented. |
| */ |
| void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out, |
| size_t len, const void *key, |
| unsigned char ivec[16], unsigned char ecount_buf[16], |
| unsigned int *num, block128_f block) |
| { |
| unsigned int n; |
| size_t l=0; |
| |
| assert(in && out && key && ecount_buf && num); |
| assert(*num < 16); |
| |
| n = *num; |
| |
| #if !defined(OPENSSL_SMALL_FOOTPRINT) |
| if (16%sizeof(size_t) == 0) do { /* always true actually */ |
| while (n && len) { |
| *(out++) = *(in++) ^ ecount_buf[n]; |
| --len; |
| n = (n+1) % 16; |
| } |
| |
| #if defined(STRICT_ALIGNMENT) |
| if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) |
| break; |
| #endif |
| while (len>=16) { |
| (*block)(ivec, ecount_buf, key); |
| ctr128_inc_aligned(ivec); |
| for (; n<16; n+=sizeof(size_t)) |
| *(size_t *)(out+n) = |
| *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n); |
| len -= 16; |
| out += 16; |
| in += 16; |
| n = 0; |
| } |
| if (len) { |
| (*block)(ivec, ecount_buf, key); |
| ctr128_inc_aligned(ivec); |
| while (len--) { |
| out[n] = in[n] ^ ecount_buf[n]; |
| ++n; |
| } |
| } |
| *num = n; |
| return; |
| } while(0); |
| /* the rest would be commonly eliminated by x86* compiler */ |
| #endif |
| while (l<len) { |
| if (n==0) { |
| (*block)(ivec, ecount_buf, key); |
| ctr128_inc(ivec); |
| } |
| out[l] = in[l] ^ ecount_buf[n]; |
| ++l; |
| n = (n+1) % 16; |
| } |
| |
| *num=n; |
| } |