212 lines
6.5 KiB
C
212 lines
6.5 KiB
C
/* ====================================================================
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* Copyright (c) 2008 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ==================================================================== */
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#include <assert.h>
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#include <string.h>
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#include "internal.h"
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void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
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const void *key, uint8_t ivec[16],
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block128_f block) {
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size_t n;
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const uint8_t *iv = ivec;
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assert(key != NULL && ivec != NULL);
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assert(len == 0 || (in != NULL && out != NULL));
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if (STRICT_ALIGNMENT &&
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((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) !=
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0) {
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while (len >= 16) {
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for (n = 0; n < 16; ++n) {
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out[n] = in[n] ^ iv[n];
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}
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(*block)(out, out, key);
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iv = out;
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len -= 16;
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in += 16;
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out += 16;
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}
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} else {
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while (len >= 16) {
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for (n = 0; n < 16; n += sizeof(size_t)) {
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store_word_le(out + n, load_word_le(in + n) ^ load_word_le(iv + n));
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}
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(*block)(out, out, key);
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iv = out;
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len -= 16;
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in += 16;
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out += 16;
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}
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}
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while (len) {
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for (n = 0; n < 16 && n < len; ++n) {
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out[n] = in[n] ^ iv[n];
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}
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for (; n < 16; ++n) {
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out[n] = iv[n];
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}
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(*block)(out, out, key);
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iv = out;
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if (len <= 16) {
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break;
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}
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len -= 16;
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in += 16;
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out += 16;
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}
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OPENSSL_memcpy(ivec, iv, 16);
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}
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void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
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const void *key, uint8_t ivec[16],
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block128_f block) {
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size_t n;
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union {
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size_t t[16 / sizeof(size_t)];
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uint8_t c[16];
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} tmp;
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assert(key != NULL && ivec != NULL);
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assert(len == 0 || (in != NULL && out != NULL));
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const uintptr_t inptr = (uintptr_t) in;
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const uintptr_t outptr = (uintptr_t) out;
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// If |in| and |out| alias, |in| must be ahead.
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assert(inptr >= outptr || inptr + len <= outptr);
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if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) {
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// If |out| is at least two blocks behind |in| or completely disjoint, there
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// is no need to decrypt to a temporary block.
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const uint8_t *iv = ivec;
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if (STRICT_ALIGNMENT &&
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((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) !=
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0) {
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while (len >= 16) {
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(*block)(in, out, key);
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for (n = 0; n < 16; ++n) {
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out[n] ^= iv[n];
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}
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iv = in;
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len -= 16;
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in += 16;
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out += 16;
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}
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} else if (16 % sizeof(size_t) == 0) { // always true
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while (len >= 16) {
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(*block)(in, out, key);
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for (n = 0; n < 16; n += sizeof(size_t)) {
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store_word_le(out + n, load_word_le(out + n) ^ load_word_le(iv + n));
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}
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iv = in;
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len -= 16;
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in += 16;
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out += 16;
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}
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}
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OPENSSL_memcpy(ivec, iv, 16);
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} else {
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// |out| is less than two blocks behind |in|. Decrypting an input block
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// directly to |out| would overwrite a ciphertext block before it is used as
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// the next block's IV. Decrypt to a temporary block instead.
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if (STRICT_ALIGNMENT &&
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((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) !=
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0) {
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uint8_t c;
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while (len >= 16) {
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(*block)(in, tmp.c, key);
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for (n = 0; n < 16; ++n) {
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c = in[n];
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out[n] = tmp.c[n] ^ ivec[n];
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ivec[n] = c;
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}
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len -= 16;
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in += 16;
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out += 16;
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}
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} else if (16 % sizeof(size_t) == 0) { // always true
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while (len >= 16) {
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(*block)(in, tmp.c, key);
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for (n = 0; n < 16; n += sizeof(size_t)) {
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size_t c = load_word_le(in + n);
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store_word_le(out + n,
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tmp.t[n / sizeof(size_t)] ^ load_word_le(ivec + n));
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store_word_le(ivec + n, c);
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}
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len -= 16;
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in += 16;
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out += 16;
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}
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}
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}
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while (len) {
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uint8_t c;
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(*block)(in, tmp.c, key);
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for (n = 0; n < 16 && n < len; ++n) {
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c = in[n];
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out[n] = tmp.c[n] ^ ivec[n];
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ivec[n] = c;
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}
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if (len <= 16) {
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for (; n < 16; ++n) {
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ivec[n] = in[n];
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}
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break;
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}
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len -= 16;
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in += 16;
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out += 16;
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}
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}
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