1// Copyright (c) 2017, Google Inc.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15#include <openssl/cipher.h>
16
17#include <string.h>
18
19#include <openssl/aes.h>
20#include <openssl/obj.h>
21
22#include "../../crypto/internal.h"
23
24typedef struct {
25  AES_KEY ks;
26} EVP_CFB_CTX;
27
28static int aes_cfb_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
29                            const uint8_t *iv, int enc) {
30  if (key) {
31    EVP_CFB_CTX *cfb_ctx = ctx->cipher_data;
32    AES_set_encrypt_key(key, ctx->key_len * 8, &cfb_ctx->ks);
33  }
34
35  return 1;
36}
37
38static int aes_cfb128_cipher(EVP_CIPHER_CTX *ctx, uint8_t *out,
39                             const uint8_t *in, size_t len) {
40  if (!out || !in) {
41    return 0;
42  }
43
44  EVP_CFB_CTX *cfb_ctx = ctx->cipher_data;
45  int num = ctx->num;
46  AES_cfb128_encrypt(in, out, len, &cfb_ctx->ks, ctx->iv, &num,
47                     ctx->encrypt ? AES_ENCRYPT : AES_DECRYPT);
48  ctx->num = num;
49
50  return 1;
51}
52
53static const EVP_CIPHER aes_128_cfb128 = {
54    NID_aes_128_cfb128,  1 /* block_size */,  16 /* key_size */,
55    16 /* iv_len */,     sizeof(EVP_CFB_CTX), EVP_CIPH_CFB_MODE,
56    NULL /* app_data */, aes_cfb_init_key,    aes_cfb128_cipher,
57    NULL /* cleanup */,  NULL /* ctrl */,
58};
59
60const EVP_CIPHER *EVP_aes_128_cfb128(void) { return &aes_128_cfb128; }
61