/* ====================================================================
* 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"
#ifndef STRICT_ALIGNMENT
# define STRICT_ALIGNMENT 0
#endif
void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
const void *key, uint8_t ivec[16],
block128_f block) {
size_t n;
const uint8_t *iv = ivec;
assert(key != NULL && ivec != NULL);
assert(len == 0 || (in != NULL && out != NULL));
if (STRICT_ALIGNMENT &&
((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
while (len >= 16) {
for (n = 0; n < 16; ++n) {
out[n] = in[n] ^ iv[n];
}
(*block)(out, out, key);
iv = out;
len -= 16;
in += 16;
out += 16;
}
} else {
while (len >= 16) {
for (n = 0; n < 16; n += sizeof(size_t)) {
*(size_t *)(out + n) = *(size_t *)(in + n) ^ *(size_t *)(iv + n);
}
(*block)(out, out, key);
iv = out;
len -= 16;
in += 16;
out += 16;
}
}
while (len) {
for (n = 0; n < 16 && n < len; ++n) {
out[n] = in[n] ^ iv[n];
}
for (; n < 16; ++n) {
out[n] = iv[n];
}
(*block)(out, out, key);
iv = out;
if (len <= 16) {
break;
}
len -= 16;
in += 16;
out += 16;
}
memcpy(ivec, iv, 16);
}
void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
const void *key, uint8_t ivec[16],
block128_f block) {
size_t n;
union {
size_t t[16 / sizeof(size_t)];
uint8_t c[16];
} tmp;
assert(key != NULL && ivec != NULL);
assert(len == 0 || (in != NULL && out != NULL));
const uintptr_t inptr = (uintptr_t) in;
const uintptr_t outptr = (uintptr_t) out;
/* If |in| and |out| alias, |in| must be ahead. */
assert(inptr >= outptr || inptr + len <= outptr);
if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) {
/* If |out| is at least two blocks behind |in| or completely disjoint, there
* is no need to decrypt to a temporary block. */
const uint8_t *iv = ivec;
if (STRICT_ALIGNMENT &&
((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
while (len >= 16) {
(*block)(in, out, key);
for (n = 0; n < 16; ++n) {
out[n] ^= iv[n];
}
iv = in;
len -= 16;
in += 16;
out += 16;
}
} else if (16 % sizeof(size_t) == 0) { /* always true */
while (len >= 16) {
size_t *out_t = (size_t *)out, *iv_t = (size_t *)iv;
(*block)(in, out, key);
for (n = 0; n < 16 / sizeof(size_t); n++) {
out_t[n] ^= iv_t[n];
}
iv = in;
len -= 16;
in += 16;
out += 16;
}
}
memcpy(ivec, iv, 16);
} else {
/* |out| is less than two blocks behind |in|. Decrypting an input block
* directly to |out| would overwrite a ciphertext block before it is used as
* the next block's IV. Decrypt to a temporary block instead. */
if (STRICT_ALIGNMENT &&
((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
uint8_t c;
while (len >= 16) {
(*block)(in, tmp.c, key);
for (n = 0; n < 16; ++n) {
c = in[n];
out[n] = tmp.c[n] ^ ivec[n];
ivec[n] = c;
}
len -= 16;
in += 16;
out += 16;
}
} else if (16 % sizeof(size_t) == 0) { /* always true */
while (len >= 16) {
size_t c, *out_t = (size_t *)out, *ivec_t = (size_t *)ivec;
const size_t *in_t = (const size_t *)in;
(*block)(in, tmp.c, key);
for (n = 0; n < 16 / sizeof(size_t); n++) {
c = in_t[n];
out_t[n] = tmp.t[n] ^ ivec_t[n];
ivec_t[n] = c;
}
len -= 16;
in += 16;
out += 16;
}
}
}
while (len) {
uint8_t c;
(*block)(in, tmp.c, key);
for (n = 0; n < 16 && n < len; ++n) {
c = in[n];
out[n] = tmp.c[n] ^ ivec[n];
ivec[n] = c;
}
if (len <= 16) {
for (; n < 16; ++n) {
ivec[n] = in[n];
}
break;
}
len -= 16;
in += 16;
out += 16;
}
}