| /* ==================================================================== |
| * 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/modes/internal.h" |
| |
| |
| typedef struct xts128_context { |
| void *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) { |
| #if STRICT_ALIGNMENT |
| OPENSSL_memcpy(scratch.c, inp, 16); |
| scratch.u[0] ^= tweak.u[0]; |
| scratch.u[1] ^= tweak.u[1]; |
| #else |
| scratch.u[0] = ((uint64_t *)inp)[0] ^ tweak.u[0]; |
| scratch.u[1] = ((uint64_t *)inp)[1] ^ tweak.u[1]; |
| #endif |
| (*ctx->block1)(scratch.c, scratch.c, ctx->key1); |
| #if STRICT_ALIGNMENT |
| scratch.u[0] ^= tweak.u[0]; |
| scratch.u[1] ^= tweak.u[1]; |
| OPENSSL_memcpy(out, scratch.c, 16); |
| #else |
| ((uint64_t *)out)[0] = scratch.u[0] ^= tweak.u[0]; |
| ((uint64_t *)out)[1] = scratch.u[1] ^= tweak.u[1]; |
| #endif |
| 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; |
| #if STRICT_ALIGNMENT |
| OPENSSL_memcpy(scratch.c, inp, 16); |
| scratch.u[0] ^= tweak1.u[0]; |
| scratch.u[1] ^= tweak1.u[1]; |
| #else |
| scratch.u[0] = ((uint64_t *)inp)[0] ^ tweak1.u[0]; |
| scratch.u[1] = ((uint64_t *)inp)[1] ^ tweak1.u[1]; |
| #endif |
| (*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); |
| #if STRICT_ALIGNMENT |
| scratch.u[0] ^= tweak.u[0]; |
| scratch.u[1] ^= tweak.u[1]; |
| OPENSSL_memcpy(out, scratch.c, 16); |
| #else |
| ((uint64_t *)out)[0] = scratch.u[0] ^ tweak.u[0]; |
| ((uint64_t *)out)[1] = scratch.u[1] ^ tweak.u[1]; |
| #endif |
| } |
| |
| 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 = (block128_f) AES_encrypt; |
| } else { |
| AES_set_decrypt_key(key, ctx->key_len * 4, &xctx->ks1.ks); |
| xctx->xts.block1 = (block128_f) AES_decrypt; |
| } |
| |
| AES_set_encrypt_key(key + ctx->key_len / 2, |
| ctx->key_len * 4, &xctx->ks2.ks); |
| xctx->xts.block2 = (block128_f) AES_encrypt; |
| xctx->xts.key1 = &xctx->ks1; |
| } |
| |
| if (iv) { |
| xctx->xts.key2 = &xctx->ks2; |
| 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) { |
| return 0; |
| } |
| xctx_out->xts.key1 = &xctx_out->ks1; |
| } |
| if (xctx->xts.key2) { |
| if (xctx->xts.key2 != &xctx->ks2) { |
| return 0; |
| } |
| xctx_out->xts.key2 = &xctx_out->ks2; |
| } |
| 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; } |