255 lines
8.8 KiB
C
255 lines
8.8 KiB
C
/* ====================================================================
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* Copyright (c) 2008 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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*/
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#include <openssl/crypto.h>
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#include "modes_lcl.h"
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#include <string.h>
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#ifndef MODES_DEBUG
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# ifndef NDEBUG
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# define NDEBUG
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# endif
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#endif
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#include <assert.h>
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/*
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* The input and output encrypted as though 128bit cfb mode is being used.
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* The extra state information to record how much of the 128bit block we have
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* used is contained in *num;
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*/
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void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
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size_t len, const void *key,
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unsigned char ivec[16], int *num,
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int enc, block128_f block)
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{
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unsigned int n;
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size_t l = 0;
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assert(in && out && key && ivec && num);
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n = *num;
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if (enc) {
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#if !defined(OPENSSL_SMALL_FOOTPRINT)
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if (16 % sizeof(size_t) == 0) { /* always true actually */
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do {
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while (n && len) {
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*(out++) = ivec[n] ^= *(in++);
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--len;
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n = (n + 1) % 16;
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}
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# if defined(STRICT_ALIGNMENT)
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if (((size_t)in | (size_t)out | (size_t)ivec) %
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sizeof(size_t) != 0)
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break;
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# endif
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while (len >= 16) {
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(*block) (ivec, ivec, key);
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for (; n < 16; n += sizeof(size_t)) {
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*(size_t *)(out + n) =
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*(size_t *)(ivec + n) ^= *(size_t *)(in + n);
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}
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len -= 16;
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out += 16;
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in += 16;
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n = 0;
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}
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if (len) {
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(*block) (ivec, ivec, key);
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while (len--) {
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out[n] = ivec[n] ^= in[n];
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++n;
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}
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}
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*num = n;
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return;
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} while (0);
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}
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/* the rest would be commonly eliminated by x86* compiler */
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#endif
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while (l < len) {
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if (n == 0) {
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(*block) (ivec, ivec, key);
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}
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out[l] = ivec[n] ^= in[l];
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++l;
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n = (n + 1) % 16;
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}
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*num = n;
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} else {
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#if !defined(OPENSSL_SMALL_FOOTPRINT)
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if (16 % sizeof(size_t) == 0) { /* always true actually */
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do {
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while (n && len) {
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unsigned char c;
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*(out++) = ivec[n] ^ (c = *(in++));
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ivec[n] = c;
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--len;
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n = (n + 1) % 16;
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}
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# if defined(STRICT_ALIGNMENT)
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if (((size_t)in | (size_t)out | (size_t)ivec) %
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sizeof(size_t) != 0)
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break;
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# endif
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while (len >= 16) {
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(*block) (ivec, ivec, key);
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for (; n < 16; n += sizeof(size_t)) {
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size_t t = *(size_t *)(in + n);
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*(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t;
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*(size_t *)(ivec + n) = t;
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}
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len -= 16;
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out += 16;
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in += 16;
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n = 0;
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}
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if (len) {
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(*block) (ivec, ivec, key);
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while (len--) {
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unsigned char c;
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out[n] = ivec[n] ^ (c = in[n]);
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ivec[n] = c;
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++n;
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}
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}
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*num = n;
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return;
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} while (0);
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}
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/* the rest would be commonly eliminated by x86* compiler */
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#endif
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while (l < len) {
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unsigned char c;
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if (n == 0) {
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(*block) (ivec, ivec, key);
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}
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out[l] = ivec[n] ^ (c = in[l]);
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ivec[n] = c;
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++l;
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n = (n + 1) % 16;
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}
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*num = n;
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}
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}
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/*
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* This expects a single block of size nbits for both in and out. Note that
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* it corrupts any extra bits in the last byte of out
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*/
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static void cfbr_encrypt_block(const unsigned char *in, unsigned char *out,
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int nbits, const void *key,
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unsigned char ivec[16], int enc,
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block128_f block)
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{
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int n, rem, num;
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unsigned char ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't
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* use) one byte off the end */
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if (nbits <= 0 || nbits > 128)
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return;
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/* fill in the first half of the new IV with the current IV */
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memcpy(ovec, ivec, 16);
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/* construct the new IV */
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(*block) (ivec, ivec, key);
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num = (nbits + 7) / 8;
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if (enc) /* encrypt the input */
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for (n = 0; n < num; ++n)
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out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
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else /* decrypt the input */
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for (n = 0; n < num; ++n)
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out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
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/* shift ovec left... */
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rem = nbits % 8;
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num = nbits / 8;
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if (rem == 0)
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memcpy(ivec, ovec + num, 16);
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else
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for (n = 0; n < 16; ++n)
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ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
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/* it is not necessary to cleanse ovec, since the IV is not secret */
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}
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/* N.B. This expects the input to be packed, MS bit first */
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void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
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size_t bits, const void *key,
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unsigned char ivec[16], int *num,
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int enc, block128_f block)
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{
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size_t n;
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unsigned char c[1], d[1];
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assert(in && out && key && ivec && num);
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assert(*num == 0);
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for (n = 0; n < bits; ++n) {
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c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
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cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
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out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
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((d[0] & 0x80) >> (unsigned int)(n % 8));
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}
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}
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void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
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size_t length, const void *key,
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unsigned char ivec[16], int *num,
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int enc, block128_f block)
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{
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size_t n;
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assert(in && out && key && ivec && num);
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assert(*num == 0);
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for (n = 0; n < length; ++n)
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cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);
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}
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