12e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// Copyright (c) 2017, Google Inc.
22e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan//
32e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// Permission to use, copy, modify, and/or distribute this software for any
42e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// purpose with or without fee is hereby granted, provided that the above
52e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// copyright notice and this permission notice appear in all copies.
62e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan//
72e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
82e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
92e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
102e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
112e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
122e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
132e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
142e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
152e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan#include <openssl/cipher.h>
162e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
172e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan#include <string.h>
182e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
192e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan#include <openssl/aes.h>
202e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan#include <openssl/obj.h>
212e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
222e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan#include "../../crypto/internal.h"
232e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
242e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloantypedef struct {
252e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  AES_KEY ks;
262e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan} EVP_CFB_CTX;
272e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
282e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloanstatic int aes_cfb_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
292e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan                            const uint8_t *iv, int enc) {
302e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  if (key) {
312e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    EVP_CFB_CTX *cfb_ctx = ctx->cipher_data;
322e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    AES_set_encrypt_key(key, ctx->key_len * 8, &cfb_ctx->ks);
332e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  }
342e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
352e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  return 1;
362e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan}
372e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
382e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloanstatic int aes_cfb128_cipher(EVP_CIPHER_CTX *ctx, uint8_t *out,
392e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan                             const uint8_t *in, size_t len) {
402e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  if (!out || !in) {
412e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    return 0;
422e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  }
432e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
442e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  EVP_CFB_CTX *cfb_ctx = ctx->cipher_data;
452e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  int num = ctx->num;
462e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  AES_cfb128_encrypt(in, out, len, &cfb_ctx->ks, ctx->iv, &num,
472e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan                     ctx->encrypt ? AES_ENCRYPT : AES_DECRYPT);
482e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  ctx->num = num;
492e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
502e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan  return 1;
512e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan}
522e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
532e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloanstatic const EVP_CIPHER aes_128_cfb128 = {
542e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    NID_aes_128_cfb128,  1 /* block_size */,  16 /* key_size */,
552e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    16 /* iv_len */,     sizeof(EVP_CFB_CTX), EVP_CIPH_CFB_MODE,
562e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    NULL /* app_data */, aes_cfb_init_key,    aes_cfb128_cipher,
572e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan    NULL /* cleanup */,  NULL /* ctrl */,
582e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan};
592e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloan
602e9e66ad8f35ee615e79da22ff91b0fa94607ca8Robert Sloanconst EVP_CIPHER *EVP_aes_128_cfb128(void) { return &aes_128_cfb128; }
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