296 lines
8.7 KiB
C
296 lines
8.7 KiB
C
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/* ====================================================================
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* Copyright (c) 2011 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 <openssl/evp.h>
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#include <string.h>
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#include <openssl/aes.h>
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#include <openssl/cipher.h>
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#include <openssl/modes.h>
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#if defined(OPENSSL_X86_64) || defined(OPENSSL_X86) || defined(OPENSSL_AARCH64)
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#define STRICT_ALIGNMENT 0
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#else
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#define STRICT_ALIGNMENT 1
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#endif
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typedef struct xts128_context {
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void *key1, *key2;
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block128_f block1, block2;
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} XTS128_CONTEXT;
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static size_t CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
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const uint8_t iv[16], const uint8_t *inp,
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uint8_t *out, size_t len, int enc) {
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const union {
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long one;
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char little;
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} is_endian = {1};
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union {
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uint64_t u[2];
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uint32_t d[4];
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uint8_t c[16];
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} tweak, scratch;
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unsigned int i;
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if (len < 16) return 0;
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memcpy(tweak.c, iv, 16);
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(*ctx->block2)(tweak.c, tweak.c, ctx->key2);
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if (!enc && (len % 16)) len -= 16;
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while (len >= 16) {
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#if defined(STRICT_ALIGNMENT)
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memcpy(scratch.c, inp, 16);
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scratch.u[0] ^= tweak.u[0];
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scratch.u[1] ^= tweak.u[1];
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#else
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scratch.u[0] = ((unint64_t *)inp)[0] ^ tweak.u[0];
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scratch.u[1] = ((unint64_t *)inp)[1] ^ tweak.u[1];
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#endif
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(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
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#if defined(STRICT_ALIGNMENT)
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scratch.u[0] ^= tweak.u[0];
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scratch.u[1] ^= tweak.u[1];
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memcpy(out, scratch.c, 16);
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#else
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((unint64_t *)out)[0] = scratch.u[0] ^= tweak.u[0];
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((unint64_t *)out)[1] = scratch.u[1] ^= tweak.u[1];
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#endif
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inp += 16;
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out += 16;
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len -= 16;
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if (len == 0) return 1;
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if (is_endian.little) {
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unsigned int carry, res;
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res = 0x87 & (((int)tweak.d[3]) >> 31);
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carry = (unsigned int)(tweak.u[0] >> 63);
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tweak.u[0] = (tweak.u[0] << 1) ^ res;
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tweak.u[1] = (tweak.u[1] << 1) | carry;
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} else {
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size_t c;
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for (c = 0, i = 0; i < 16; ++i) {
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/*
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* + substitutes for |, because c is 1 bit
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*/
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c += ((size_t)tweak.c[i]) << 1;
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tweak.c[i] = (uint8_t)c;
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c = c >> 8;
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}
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tweak.c[0] ^= (uint8_t)(0x87 & (0 - c));
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}
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}
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if (enc) {
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for (i = 0; i < len; ++i) {
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uint8_t c = inp[i];
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out[i] = scratch.c[i];
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scratch.c[i] = c;
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}
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scratch.u[0] ^= tweak.u[0];
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scratch.u[1] ^= tweak.u[1];
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(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
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scratch.u[0] ^= tweak.u[0];
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scratch.u[1] ^= tweak.u[1];
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memcpy(out - 16, scratch.c, 16);
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} else {
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union {
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uint64_t u[2];
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uint8_t c[16];
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} tweak1;
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if (is_endian.little) {
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unsigned int carry, res;
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res = 0x87 & (((int)tweak.d[3]) >> 31);
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carry = (unsigned int)(tweak.u[0] >> 63);
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tweak1.u[0] = (tweak.u[0] << 1) ^ res;
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tweak1.u[1] = (tweak.u[1] << 1) | carry;
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} else {
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size_t c;
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for (c = 0, i = 0; i < 16; ++i) {
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/*
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* + substitutes for |, because c is 1 bit
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*/
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c += ((size_t)tweak.c[i]) << 1;
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tweak1.c[i] = (uint8_t)c;
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c = c >> 8;
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}
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tweak1.c[0] ^= (uint8_t)(0x87 & (0 - c));
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}
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#if defined(STRICT_ALIGNMENT)
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memcpy(scratch.c, inp, 16);
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scratch.u[0] ^= tweak1.u[0];
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scratch.u[1] ^= tweak1.u[1];
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#else
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scratch.u[0] = ((unint64_t *)inp)[0] ^ tweak1.u[0];
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scratch.u[1] = ((unint64_t *)inp)[1] ^ tweak1.u[1];
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#endif
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(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
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scratch.u[0] ^= tweak1.u[0];
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scratch.u[1] ^= tweak1.u[1];
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for (i = 0; i < len; ++i) {
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uint8_t c = inp[16 + i];
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out[16 + i] = scratch.c[i];
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scratch.c[i] = c;
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}
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scratch.u[0] ^= tweak.u[0];
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scratch.u[1] ^= tweak.u[1];
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(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
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#if defined(STRICT_ALIGNMENT)
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scratch.u[0] ^= tweak.u[0];
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scratch.u[1] ^= tweak.u[1];
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memcpy(out, scratch.c, 16);
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#else
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((unint64_t *)out)[0] = scratch.u[0] ^ tweak.u[0];
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((unint64_t *)out)[1] = scratch.u[1] ^ tweak.u[1];
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#endif
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}
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return 1;
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}
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typedef struct {
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union {
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double align;
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AES_KEY ks;
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} ks1, ks2; /* AES key schedules to use */
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XTS128_CONTEXT xts;
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} EVP_AES_XTS_CTX;
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static int aes_xts_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
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const uint8_t *iv, int enc) {
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EVP_AES_XTS_CTX *xctx = ctx->cipher_data;
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if (!iv && !key) {
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return 1;
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}
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if (key) {
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/* key_len is two AES keys */
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if (enc) {
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AES_set_encrypt_key(key, ctx->key_len * 4, &xctx->ks1.ks);
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xctx->xts.block1 = (block128_f) AES_encrypt;
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} else {
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AES_set_decrypt_key(key, ctx->key_len * 4, &xctx->ks1.ks);
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xctx->xts.block1 = (block128_f) AES_decrypt;
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}
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AES_set_encrypt_key(key + ctx->key_len / 2,
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ctx->key_len * 4, &xctx->ks2.ks);
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xctx->xts.block2 = (block128_f) AES_encrypt;
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xctx->xts.key1 = &xctx->ks1;
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}
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if (iv) {
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xctx->xts.key2 = &xctx->ks2;
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memcpy(ctx->iv, iv, 16);
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}
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return 1;
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}
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static int aes_xts_cipher(EVP_CIPHER_CTX *ctx, uint8_t *out,
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const uint8_t *in, size_t len) {
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EVP_AES_XTS_CTX *xctx = ctx->cipher_data;
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if (!xctx->xts.key1 ||
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!xctx->xts.key2 ||
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!out ||
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!in ||
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len < AES_BLOCK_SIZE ||
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!CRYPTO_xts128_encrypt(&xctx->xts, ctx->iv, in, out, len, ctx->encrypt)) {
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return 0;
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}
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return 1;
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}
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static int aes_xts_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr) {
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EVP_AES_XTS_CTX *xctx = c->cipher_data;
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if (type == EVP_CTRL_COPY) {
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EVP_CIPHER_CTX *out = ptr;
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EVP_AES_XTS_CTX *xctx_out = out->cipher_data;
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if (xctx->xts.key1) {
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if (xctx->xts.key1 != &xctx->ks1) {
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return 0;
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}
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xctx_out->xts.key1 = &xctx_out->ks1;
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}
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if (xctx->xts.key2) {
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if (xctx->xts.key2 != &xctx->ks2) {
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return 0;
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}
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xctx_out->xts.key2 = &xctx_out->ks2;
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}
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return 1;
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} else if (type != EVP_CTRL_INIT) {
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return -1;
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}
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/* key1 and key2 are used as an indicator both key and IV are set */
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xctx->xts.key1 = NULL;
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xctx->xts.key2 = NULL;
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return 1;
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}
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static const EVP_CIPHER aes_256_xts = {
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NID_aes_256_xts, 1 /* block_size */, 32 /* key_size */,
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16 /* iv_len */, sizeof(EVP_AES_XTS_CTX),
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EVP_CIPH_XTS_MODE | EVP_CIPH_CUSTOM_IV | EVP_CIPH_ALWAYS_CALL_INIT |
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EVP_CIPH_CTRL_INIT | EVP_CIPH_CUSTOM_COPY,
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NULL /* app_data */, aes_xts_init_key, aes_xts_cipher,
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NULL /* cleanup */, aes_xts_ctrl};
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const EVP_CIPHER *EVP_aes_256_xts(void) { return &aes_256_xts; }
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