252 lines
6.8 KiB
C
252 lines
6.8 KiB
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/crypto.h>
|
|
#include "modes_lcl.h"
|
|
#include <string.h>
|
|
|
|
#ifndef MODES_DEBUG
|
|
# ifndef NDEBUG
|
|
# define NDEBUG
|
|
# endif
|
|
#endif
|
|
#include <assert.h>
|
|
|
|
/* NOTE: the IV/counter CTR mode is big-endian. The code itself
|
|
* is endian-neutral. */
|
|
|
|
/* increment counter (128-bit int) by 1 */
|
|
static void ctr128_inc(unsigned char *counter) {
|
|
u32 n=16;
|
|
u8 c;
|
|
|
|
do {
|
|
--n;
|
|
c = counter[n];
|
|
++c;
|
|
counter[n] = c;
|
|
if (c) return;
|
|
} while (n);
|
|
}
|
|
|
|
#if !defined(OPENSSL_SMALL_FOOTPRINT)
|
|
static void ctr128_inc_aligned(unsigned char *counter) {
|
|
size_t *data,c,n;
|
|
const union { long one; char little; } is_endian = {1};
|
|
|
|
if (is_endian.little) {
|
|
ctr128_inc(counter);
|
|
return;
|
|
}
|
|
|
|
data = (size_t *)counter;
|
|
n = 16/sizeof(size_t);
|
|
do {
|
|
--n;
|
|
c = data[n];
|
|
++c;
|
|
data[n] = c;
|
|
if (c) return;
|
|
} while (n);
|
|
}
|
|
#endif
|
|
|
|
/* The input encrypted as though 128bit counter mode is being
|
|
* used. The extra state information to record how much of the
|
|
* 128bit block we have used is contained in *num, and the
|
|
* encrypted counter is kept in ecount_buf. Both *num and
|
|
* ecount_buf must be initialised with zeros before the first
|
|
* call to CRYPTO_ctr128_encrypt().
|
|
*
|
|
* This algorithm assumes that the counter is in the x lower bits
|
|
* of the IV (ivec), and that the application has full control over
|
|
* overflow and the rest of the IV. This implementation takes NO
|
|
* responsability for checking that the counter doesn't overflow
|
|
* into the rest of the IV when incremented.
|
|
*/
|
|
void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
|
|
size_t len, const void *key,
|
|
unsigned char ivec[16], unsigned char ecount_buf[16],
|
|
unsigned int *num, block128_f block)
|
|
{
|
|
unsigned int n;
|
|
size_t l=0;
|
|
|
|
assert(in && out && key && ecount_buf && num);
|
|
assert(*num < 16);
|
|
|
|
n = *num;
|
|
|
|
#if !defined(OPENSSL_SMALL_FOOTPRINT)
|
|
if (16%sizeof(size_t) == 0) do { /* always true actually */
|
|
while (n && len) {
|
|
*(out++) = *(in++) ^ ecount_buf[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, ecount_buf, key);
|
|
ctr128_inc_aligned(ivec);
|
|
for (; n<16; n+=sizeof(size_t))
|
|
*(size_t *)(out+n) =
|
|
*(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n);
|
|
len -= 16;
|
|
out += 16;
|
|
in += 16;
|
|
n = 0;
|
|
}
|
|
if (len) {
|
|
(*block)(ivec, ecount_buf, key);
|
|
ctr128_inc_aligned(ivec);
|
|
while (len--) {
|
|
out[n] = in[n] ^ ecount_buf[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, ecount_buf, key);
|
|
ctr128_inc(ivec);
|
|
}
|
|
out[l] = in[l] ^ ecount_buf[n];
|
|
++l;
|
|
n = (n+1) % 16;
|
|
}
|
|
|
|
*num=n;
|
|
}
|
|
|
|
/* increment upper 96 bits of 128-bit counter by 1 */
|
|
static void ctr96_inc(unsigned char *counter) {
|
|
u32 n=12;
|
|
u8 c;
|
|
|
|
do {
|
|
--n;
|
|
c = counter[n];
|
|
++c;
|
|
counter[n] = c;
|
|
if (c) return;
|
|
} while (n);
|
|
}
|
|
|
|
void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out,
|
|
size_t len, const void *key,
|
|
unsigned char ivec[16], unsigned char ecount_buf[16],
|
|
unsigned int *num, ctr128_f func)
|
|
{
|
|
unsigned int n,ctr32;
|
|
|
|
assert(in && out && key && ecount_buf && num);
|
|
assert(*num < 16);
|
|
|
|
n = *num;
|
|
|
|
while (n && len) {
|
|
*(out++) = *(in++) ^ ecount_buf[n];
|
|
--len;
|
|
n = (n+1) % 16;
|
|
}
|
|
|
|
ctr32 = GETU32(ivec+12);
|
|
while (len>=16) {
|
|
size_t blocks = len/16;
|
|
/*
|
|
* 1<<28 is just a not-so-small yet not-so-large number...
|
|
* Below condition is practically never met, but it has to
|
|
* be checked for code correctness.
|
|
*/
|
|
if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
|
|
blocks = (1U<<28);
|
|
/*
|
|
* As (*func) operates on 32-bit counter, caller
|
|
* has to handle overflow. 'if' below detects the
|
|
* overflow, which is then handled by limiting the
|
|
* amount of blocks to the exact overflow point...
|
|
*/
|
|
ctr32 += (u32)blocks;
|
|
if (ctr32 < blocks) {
|
|
blocks -= ctr32;
|
|
ctr32 = 0;
|
|
}
|
|
(*func)(in,out,blocks,key,ivec);
|
|
/* (*ctr) does not update ivec, caller does: */
|
|
PUTU32(ivec+12,ctr32);
|
|
/* ... overflow was detected, propogate carry. */
|
|
if (ctr32 == 0) ctr96_inc(ivec);
|
|
blocks *= 16;
|
|
len -= blocks;
|
|
out += blocks;
|
|
in += blocks;
|
|
}
|
|
if (len) {
|
|
memset(ecount_buf,0,16);
|
|
(*func)(ecount_buf,ecount_buf,1,key,ivec);
|
|
++ctr32;
|
|
PUTU32(ivec+12,ctr32);
|
|
if (ctr32 == 0) ctr96_inc(ivec);
|
|
while (len--) {
|
|
out[n] = in[n] ^ ecount_buf[n];
|
|
++n;
|
|
}
|
|
}
|
|
|
|
*num=n;
|
|
}
|