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/*
* Copyright 2008-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/crypto.h>
#include "modes_local.h"
#include <string.h>
#if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
typedef size_t size_t_aX __attribute((__aligned__(1)));
#else
typedef size_t size_t_aX;
#endif
/*
* The input and output encrypted as though 128bit ofb mode is being used.
* The extra state information to record how much of the 128bit block we have
* used is contained in *num;
*/
void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16], int *num, block128_f block)
{
unsigned int n;
size_t l = 0;
n = *num;
#if !defined(OPENSSL_SMALL_FOOTPRINT)
if (16 % sizeof(size_t) == 0) { /* always true actually */
do {
while (n && len) {
*(out++) = *(in++) ^ ivec[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, ivec, key);
for (; n < 16; n += sizeof(size_t))
*(size_t_aX *)(out + n) =
*(size_t_aX *)(in + n)
^ *(size_t_aX *)(ivec + n);
len -= 16;
out += 16;
in += 16;
n = 0;
}
if (len) {
(*block) (ivec, ivec, key);
while (len--) {
out[n] = in[n] ^ ivec[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, ivec, key);
}
out[l] = in[l] ^ ivec[n];
++l;
n = (n + 1) % 16;
}
*num = n;
}
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