Line data    Source code

       1             : /*
       2             :  * AES-128 CBC
       3             :  *
       4             :  * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
       5             :  *
       6             :  * This software may be distributed under the terms of the BSD license.
       7             :  * See README for more details.
       8             :  */
       9             : 
      10             : #include "includes.h"
      11             : 
      12             : #include "common.h"
      13             : #include "aes.h"
      14             : #include "aes_wrap.h"
      15             : 
      16             : /**
      17             :  * aes_128_cbc_encrypt - AES-128 CBC encryption
      18             :  * @key: Encryption key
      19             :  * @iv: Encryption IV for CBC mode (16 bytes)
      20             :  * @data: Data to encrypt in-place
      21             :  * @data_len: Length of data in bytes (must be divisible by 16)
      22             :  * Returns: 0 on success, -1 on failure
      23             :  */
      24         153 : int aes_128_cbc_encrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
      25             : {
      26             :         void *ctx;
      27             :         u8 cbc[AES_BLOCK_SIZE];
      28         153 :         u8 *pos = data;
      29             :         int i, j, blocks;
      30             : 
      31         153 :         ctx = aes_encrypt_init(key, 16);
      32         153 :         if (ctx == NULL)
      33           0 :                 return -1;
      34         153 :         os_memcpy(cbc, iv, AES_BLOCK_SIZE);
      35             : 
      36         153 :         blocks = data_len / AES_BLOCK_SIZE;
      37         793 :         for (i = 0; i < blocks; i++) {
      38       10880 :                 for (j = 0; j < AES_BLOCK_SIZE; j++)
      39       10240 :                         cbc[j] ^= pos[j];
      40         640 :                 aes_encrypt(ctx, cbc, cbc);
      41         640 :                 os_memcpy(pos, cbc, AES_BLOCK_SIZE);
      42         640 :                 pos += AES_BLOCK_SIZE;
      43             :         }
      44         153 :         aes_encrypt_deinit(ctx);
      45         153 :         return 0;
      46             : }
      47             : 
      48             : 
      49             : /**
      50             :  * aes_128_cbc_decrypt - AES-128 CBC decryption
      51             :  * @key: Decryption key
      52             :  * @iv: Decryption IV for CBC mode (16 bytes)
      53             :  * @data: Data to decrypt in-place
      54             :  * @data_len: Length of data in bytes (must be divisible by 16)
      55             :  * Returns: 0 on success, -1 on failure
      56             :  */
      57         122 : int aes_128_cbc_decrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
      58             : {
      59             :         void *ctx;
      60             :         u8 cbc[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
      61         122 :         u8 *pos = data;
      62             :         int i, j, blocks;
      63             : 
      64         122 :         ctx = aes_decrypt_init(key, 16);
      65         122 :         if (ctx == NULL)
      66           0 :                 return -1;
      67         122 :         os_memcpy(cbc, iv, AES_BLOCK_SIZE);
      68             : 
      69         122 :         blocks = data_len / AES_BLOCK_SIZE;
      70         498 :         for (i = 0; i < blocks; i++) {
      71         376 :                 os_memcpy(tmp, pos, AES_BLOCK_SIZE);
      72         376 :                 aes_decrypt(ctx, pos, pos);
      73        6392 :                 for (j = 0; j < AES_BLOCK_SIZE; j++)
      74        6016 :                         pos[j] ^= cbc[j];
      75         376 :                 os_memcpy(cbc, tmp, AES_BLOCK_SIZE);
      76         376 :                 pos += AES_BLOCK_SIZE;
      77             :         }
      78         122 :         aes_decrypt_deinit(ctx);
      79         122 :         return 0;
      80             : }