зеркало из https://github.com/Azure/sonic-openssh.git
84 строки
2.1 KiB
C
84 строки
2.1 KiB
C
/* $OpenBSD: cipher-aesctr.c,v 1.2 2015/01/14 10:24:42 markus Exp $ */
|
|
/*
|
|
* Copyright (c) 2003 Markus Friedl. All rights reserved.
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*/
|
|
|
|
#include "includes.h"
|
|
|
|
#include <sys/types.h>
|
|
#include <string.h>
|
|
|
|
#ifndef WITH_OPENSSL
|
|
|
|
#include "cipher-aesctr.h"
|
|
|
|
/*
|
|
* increment counter 'ctr',
|
|
* the counter is of size 'len' bytes and stored in network-byte-order.
|
|
* (LSB at ctr[len-1], MSB at ctr[0])
|
|
*/
|
|
static inline void
|
|
aesctr_inc(u8 *ctr, u32 len)
|
|
{
|
|
ssize_t i;
|
|
|
|
#ifndef CONSTANT_TIME_INCREMENT
|
|
for (i = len - 1; i >= 0; i--)
|
|
if (++ctr[i]) /* continue on overflow */
|
|
return;
|
|
#else
|
|
u8 x, add = 1;
|
|
|
|
for (i = len - 1; i >= 0; i--) {
|
|
ctr[i] += add;
|
|
/* constant time for: x = ctr[i] ? 1 : 0 */
|
|
x = ctr[i];
|
|
x = (x | (x >> 4)) & 0xf;
|
|
x = (x | (x >> 2)) & 0x3;
|
|
x = (x | (x >> 1)) & 0x1;
|
|
add *= (x^1);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
void
|
|
aesctr_keysetup(aesctr_ctx *x,const u8 *k,u32 kbits,u32 ivbits)
|
|
{
|
|
x->rounds = rijndaelKeySetupEnc(x->ek, k, kbits);
|
|
}
|
|
|
|
void
|
|
aesctr_ivsetup(aesctr_ctx *x,const u8 *iv)
|
|
{
|
|
memcpy(x->ctr, iv, AES_BLOCK_SIZE);
|
|
}
|
|
|
|
void
|
|
aesctr_encrypt_bytes(aesctr_ctx *x,const u8 *m,u8 *c,u32 bytes)
|
|
{
|
|
u32 n = 0;
|
|
u8 buf[AES_BLOCK_SIZE];
|
|
|
|
while ((bytes--) > 0) {
|
|
if (n == 0) {
|
|
rijndaelEncrypt(x->ek, x->rounds, x->ctr, buf);
|
|
aesctr_inc(x->ctr, AES_BLOCK_SIZE);
|
|
}
|
|
*(c++) = *(m++) ^ buf[n];
|
|
n = (n + 1) % AES_BLOCK_SIZE;
|
|
}
|
|
}
|
|
#endif /* !WITH_OPENSSL */
|