src/pluto/alg/ike_alg_aes.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stddef.h>
   4 #include <sys/types.h>
   5 #include <freeswan.h>
   6
   7 #include "constants.h"
   8 #include "defs.h"
   9 #include "log.h"
  10 #include "libaes/aes_cbc.h"
  11 #include "alg_info.h"
  12 #include "ike_alg.h"
  13
  14 #define  AES_CBC_BLOCK_SIZE     (128/BITS_PER_BYTE)
  15 #define  AES_KEY_MIN_LEN        128
  16 #define  AES_KEY_DEF_LEN        128
  17 #define  AES_KEY_MAX_LEN        256
  18
  19 static void
  20 do_aes(u_int8_t *buf, size_t buf_len, u_int8_t *key, size_t key_size, u_int8_t *iv, bool enc)
  21 {
  22     aes_context aes_ctx;
  23     char iv_bak[AES_CBC_BLOCK_SIZE];
  24     char *new_iv = NULL;        /* logic will avoid copy to NULL */
  25
  26     aes_set_key(&aes_ctx, key, key_size, 0);
  27
  28     /*
  29      *  my AES cbc does not touch passed IV (optimization for
  30      *  ESP handling), so I must "emulate" des-like IV
  31      *  crunching
  32      */
  33     if (!enc)
  34         memcpy(new_iv=iv_bak, (char*) buf + buf_len - AES_CBC_BLOCK_SIZE
  35                 , AES_CBC_BLOCK_SIZE);
  36
  37     SS_AES_cbc_encrypt(&aes_ctx, buf, buf, buf_len, iv, enc);
  38
  39     if (enc)
  40         new_iv = (char*) buf + buf_len-AES_CBC_BLOCK_SIZE;
  41
  42     memcpy(iv, new_iv, AES_CBC_BLOCK_SIZE);
  43 }
  44
  45 struct encrypt_desc algo_aes =
  46 {
  47         algo_type:      IKE_ALG_ENCRYPT,
  48         algo_id:        OAKLEY_AES_CBC,
  49         algo_next:      NULL,
  50         enc_ctxsize:    sizeof(aes_context),
  51         enc_blocksize:  AES_CBC_BLOCK_SIZE,
  52         keyminlen:      AES_KEY_MIN_LEN,
  53         keydeflen:      AES_KEY_DEF_LEN,
  54         keymaxlen:      AES_KEY_MAX_LEN,
  55         do_crypt:       do_aes,
  56 };
  57
  58 int ike_alg_aes_init(void);
  59
  60 int
  61 ike_alg_aes_init(void)
  62 {
  63         int ret = ike_alg_register_enc(&algo_aes);
  64         return ret;
  65 }
  66 /*
  67 IKE_ALG_INIT_NAME: ike_alg_aes_init
  68 */