ref: 8bc69a872883224675a55db51ac8f60ab5ed9e5a
dir: /third_party/boringssl/src/decrepit/xts/xts.c/
/* ====================================================================
* Copyright (c) 2011 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/evp.h>
#include <string.h>
#include <openssl/aes.h>
#include <openssl/cipher.h>
#include "../crypto/fipsmodule/modes/internal.h"
typedef struct xts128_context {
AES_KEY *key1, *key2;
block128_f block1, block2;
} XTS128_CONTEXT;
static size_t CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
const uint8_t iv[16], const uint8_t *inp,
uint8_t *out, size_t len, int enc) {
union {
uint64_t u[2];
uint32_t d[4];
uint8_t c[16];
} tweak, scratch;
unsigned int i;
if (len < 16) return 0;
OPENSSL_memcpy(tweak.c, iv, 16);
(*ctx->block2)(tweak.c, tweak.c, ctx->key2);
if (!enc && (len % 16)) len -= 16;
while (len >= 16) {
OPENSSL_memcpy(scratch.c, inp, 16);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
OPENSSL_memcpy(out, scratch.c, 16);
inp += 16;
out += 16;
len -= 16;
if (len == 0) return 1;
unsigned int carry, res;
res = 0x87 & (((int)tweak.d[3]) >> 31);
carry = (unsigned int)(tweak.u[0] >> 63);
tweak.u[0] = (tweak.u[0] << 1) ^ res;
tweak.u[1] = (tweak.u[1] << 1) | carry;
}
if (enc) {
for (i = 0; i < len; ++i) {
uint8_t c = inp[i];
out[i] = scratch.c[i];
scratch.c[i] = c;
}
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
OPENSSL_memcpy(out - 16, scratch.c, 16);
} else {
union {
uint64_t u[2];
uint8_t c[16];
} tweak1;
unsigned int carry, res;
res = 0x87 & (((int)tweak.d[3]) >> 31);
carry = (unsigned int)(tweak.u[0] >> 63);
tweak1.u[0] = (tweak.u[0] << 1) ^ res;
tweak1.u[1] = (tweak.u[1] << 1) | carry;
OPENSSL_memcpy(scratch.c, inp, 16);
scratch.u[0] ^= tweak1.u[0];
scratch.u[1] ^= tweak1.u[1];
(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
scratch.u[0] ^= tweak1.u[0];
scratch.u[1] ^= tweak1.u[1];
for (i = 0; i < len; ++i) {
uint8_t c = inp[16 + i];
out[16 + i] = scratch.c[i];
scratch.c[i] = c;
}
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1)(scratch.c, scratch.c, ctx->key1);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
OPENSSL_memcpy(out, scratch.c, 16);
}
return 1;
}
typedef struct {
union {
double align;
AES_KEY ks;
} ks1, ks2; // AES key schedules to use
XTS128_CONTEXT xts;
} EVP_AES_XTS_CTX;
static int aes_xts_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
const uint8_t *iv, int enc) {
EVP_AES_XTS_CTX *xctx = ctx->cipher_data;
if (!iv && !key) {
return 1;
}
if (key) {
// key_len is two AES keys
if (enc) {
AES_set_encrypt_key(key, ctx->key_len * 4, &xctx->ks1.ks);
xctx->xts.block1 = AES_encrypt;
} else {
AES_set_decrypt_key(key, ctx->key_len * 4, &xctx->ks1.ks);
xctx->xts.block1 = AES_decrypt;
}
AES_set_encrypt_key(key + ctx->key_len / 2,
ctx->key_len * 4, &xctx->ks2.ks);
xctx->xts.block2 = AES_encrypt;
xctx->xts.key1 = &xctx->ks1.ks;
}
if (iv) {
xctx->xts.key2 = &xctx->ks2.ks;
OPENSSL_memcpy(ctx->iv, iv, 16);
}
return 1;
}
static int aes_xts_cipher(EVP_CIPHER_CTX *ctx, uint8_t *out,
const uint8_t *in, size_t len) {
EVP_AES_XTS_CTX *xctx = ctx->cipher_data;
if (!xctx->xts.key1 ||
!xctx->xts.key2 ||
!out ||
!in ||
len < AES_BLOCK_SIZE ||
!CRYPTO_xts128_encrypt(&xctx->xts, ctx->iv, in, out, len, ctx->encrypt)) {
return 0;
}
return 1;
}
static int aes_xts_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr) {
EVP_AES_XTS_CTX *xctx = c->cipher_data;
if (type == EVP_CTRL_COPY) {
EVP_CIPHER_CTX *out = ptr;
EVP_AES_XTS_CTX *xctx_out = out->cipher_data;
if (xctx->xts.key1) {
if (xctx->xts.key1 != &xctx->ks1.ks) {
return 0;
}
xctx_out->xts.key1 = &xctx_out->ks1.ks;
}
if (xctx->xts.key2) {
if (xctx->xts.key2 != &xctx->ks2.ks) {
return 0;
}
xctx_out->xts.key2 = &xctx_out->ks2.ks;
}
return 1;
} else if (type != EVP_CTRL_INIT) {
return -1;
}
// key1 and key2 are used as an indicator both key and IV are set
xctx->xts.key1 = NULL;
xctx->xts.key2 = NULL;
return 1;
}
static const EVP_CIPHER aes_256_xts = {
NID_aes_256_xts, 1 /* block_size */, 64 /* key_size (2 AES keys) */,
16 /* iv_len */, sizeof(EVP_AES_XTS_CTX),
EVP_CIPH_XTS_MODE | EVP_CIPH_CUSTOM_IV | EVP_CIPH_ALWAYS_CALL_INIT |
EVP_CIPH_CTRL_INIT | EVP_CIPH_CUSTOM_COPY,
NULL /* app_data */, aes_xts_init_key, aes_xts_cipher,
NULL /* cleanup */, aes_xts_ctrl};
const EVP_CIPHER *EVP_aes_256_xts(void) { return &aes_256_xts; }