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- /* ====================================================================
- * 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 <openssl/modes.h>
-
- #include <assert.h>
- #include <string.h>
-
- #include "internal.h"
-
-
- void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
- const void *key, uint8_t ivec[16], int *num, int enc,
- block128_f block) {
- unsigned int n;
- size_t l = 0;
-
- assert(in && out && key && ivec && num);
- assert((16 % sizeof(size_t)) == 0);
-
- n = *num;
-
- if (enc) {
- while (n && len) {
- *(out++) = ivec[n] ^= *(in++);
- --len;
- n = (n + 1) % 16;
- }
- #if STRICT_ALIGNMENT
- if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
- while (l < len) {
- if (n == 0) {
- (*block)(ivec, ivec, key);
- }
- out[l] = ivec[n] ^= in[l];
- ++l;
- n = (n + 1) % 16;
- }
- *num = n;
- return;
- }
- #endif
- while (len >= 16) {
- (*block)(ivec, ivec, key);
- for (; n < 16; n += sizeof(size_t)) {
- *(size_t *)(out + n) = *(size_t *)(ivec + n) ^= *(size_t *)(in + n);
- }
- len -= 16;
- out += 16;
- in += 16;
- n = 0;
- }
- if (len) {
- (*block)(ivec, ivec, key);
- while (len--) {
- out[n] = ivec[n] ^= in[n];
- ++n;
- }
- }
- *num = n;
- return;
- } else {
- while (n && len) {
- uint8_t c;
- *(out++) = ivec[n] ^ (c = *(in++));
- ivec[n] = c;
- --len;
- n = (n + 1) % 16;
- }
- if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
- while (l < len) {
- unsigned char c;
- if (n == 0) {
- (*block)(ivec, ivec, key);
- }
- out[l] = ivec[n] ^ (c = in[l]);
- ivec[n] = c;
- ++l;
- n = (n + 1) % 16;
- }
- *num = n;
- return;
- }
- while (len >= 16) {
- (*block)(ivec, ivec, key);
- for (; n < 16; n += sizeof(size_t)) {
- size_t t = *(size_t *)(in + n);
- *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t;
- *(size_t *)(ivec + n) = t;
- }
- len -= 16;
- out += 16;
- in += 16;
- n = 0;
- }
- if (len) {
- (*block)(ivec, ivec, key);
- while (len--) {
- uint8_t c;
- out[n] = ivec[n] ^ (c = in[n]);
- ivec[n] = c;
- ++n;
- }
- }
- *num = n;
- return;
- }
- }
-
-
- /* This expects a single block of size nbits for both in and out. Note that
- it corrupts any extra bits in the last byte of out */
- static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits,
- const void *key, uint8_t ivec[16], int enc,
- block128_f block) {
- int n, rem, num;
- uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one
- byte off the end */
-
- if (nbits <= 0 || nbits > 128) {
- return;
- }
-
- /* fill in the first half of the new IV with the current IV */
- memcpy(ovec, ivec, 16);
- /* construct the new IV */
- (*block)(ivec, ivec, key);
- num = (nbits + 7) / 8;
- if (enc) {
- /* encrypt the input */
- for (n = 0; n < num; ++n) {
- out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
- }
- } else {
- /* decrypt the input */
- for (n = 0; n < num; ++n) {
- out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
- }
- }
- /* shift ovec left... */
- rem = nbits % 8;
- num = nbits / 8;
- if (rem == 0) {
- memcpy(ivec, ovec + num, 16);
- } else {
- for (n = 0; n < 16; ++n) {
- ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
- }
- }
-
- /* it is not necessary to cleanse ovec, since the IV is not secret */
- }
-
- /* N.B. This expects the input to be packed, MS bit first */
- void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits,
- const void *key, uint8_t ivec[16], int *num,
- int enc, block128_f block) {
- size_t n;
- uint8_t c[1], d[1];
-
- assert(in && out && key && ivec && num);
- assert(*num == 0);
-
- for (n = 0; n < bits; ++n) {
- c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
- cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
- out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
- ((d[0] & 0x80) >> (unsigned int)(n % 8));
- }
- }
-
- void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
- size_t length, const void *key,
- unsigned char ivec[16], int *num, int enc,
- block128_f block) {
- size_t n;
-
- assert(in && out && key && ivec && num);
- assert(*num == 0);
-
- for (n = 0; n < length; ++n) {
- cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);
- }
- }
-
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