ref: 98c1cd7ae022efe276123898af6b892eade0732c
dir: /third_party/boringssl/src/crypto/fipsmodule/modes/cfb.c/
/* ====================================================================
* 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/type_check.h>
#include <assert.h>
#include <string.h>
#include "internal.h"
OPENSSL_STATIC_ASSERT(16 % sizeof(size_t) == 0,
"block cannot be divided into size_t");
void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
const AES_KEY *key, uint8_t ivec[16], unsigned *num,
int enc, block128_f block) {
assert(in && out && key && ivec && num);
unsigned n = *num;
if (enc) {
while (n && len) {
*(out++) = ivec[n] ^= *(in++);
--len;
n = (n + 1) % 16;
}
while (len >= 16) {
(*block)(ivec, ivec, key);
for (; n < 16; n += sizeof(crypto_word_t)) {
crypto_word_t tmp =
CRYPTO_load_word_le(ivec + n) ^ CRYPTO_load_word_le(in + n);
CRYPTO_store_word_le(ivec + n, tmp);
CRYPTO_store_word_le(out + n, tmp);
}
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;
}
while (len >= 16) {
(*block)(ivec, ivec, key);
for (; n < 16; n += sizeof(crypto_word_t)) {
crypto_word_t t = CRYPTO_load_word_le(in + n);
CRYPTO_store_word_le(out + n, CRYPTO_load_word_le(ivec + n) ^ t);
CRYPTO_store_word_le(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 AES_KEY *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
OPENSSL_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) {
OPENSSL_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 AES_KEY *key, uint8_t ivec[16],
unsigned *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 AES_KEY *key,
unsigned char ivec[16], unsigned *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);
}
}