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// Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <contrib/restricted/google/boringssl/include/openssl/evp.h>
#include <string.h>
#include <contrib/restricted/google/boringssl/include/openssl/aes.h>
#include <contrib/restricted/google/boringssl/include/openssl/cipher.h>
#include "../../crypto/fipsmodule/cipher/internal.h"
#include "../../crypto/fipsmodule/aes/internal.h"
using namespace bssl;
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 = reinterpret_cast<EVP_AES_XTS_CTX *>(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_update(EVP_CIPHER_CTX *ctx, uint8_t *out,
const uint8_t *in, size_t len) {
EVP_AES_XTS_CTX *xctx = reinterpret_cast<EVP_AES_XTS_CTX *>(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 = reinterpret_cast<EVP_AES_XTS_CTX *>(c->cipher_data);
if (type == EVP_CTRL_COPY) {
EVP_CIPHER_CTX *out = reinterpret_cast<EVP_CIPHER_CTX *>(ptr);
EVP_AES_XTS_CTX *xctx_out =
reinterpret_cast<EVP_AES_XTS_CTX *>(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 = nullptr;
xctx->xts.key2 = nullptr;
return 1;
}
static const EVP_CIPHER aes_256_xts = {
/* nid= */ NID_aes_256_xts,
/* block_size= */ 1,
/* key_len= */ 64 /* 2 AES-256 keys */,
/* iv_len= */ 16,
/* ctx_size= */ sizeof(EVP_AES_XTS_CTX),
/* flags= */ EVP_CIPH_XTS_MODE | EVP_CIPH_CUSTOM_IV |
EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CTRL_INIT | EVP_CIPH_CUSTOM_COPY,
/* init= */ aes_xts_init_key,
/* cipher_update= */ aes_xts_cipher_update,
/* cipher_final= */ nullptr,
/* update_aad= */ nullptr,
/* cleanup= */ nullptr,
/* ctrl= */ aes_xts_ctrl,
};
const EVP_CIPHER *EVP_aes_256_xts() { return &aes_256_xts; }
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