programs/pluto/alg/ike_alg_serpent.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 "libserpent/serpent_cbc.h"
  11 #include "alg_info.h"
  12 #include "ike_alg.h"
  13
  14 #define  SERPENT_CBC_BLOCK_SIZE (128/BITS_PER_BYTE)
  15 #define  SERPENT_KEY_MIN_LEN    128
  16 #define  SERPENT_KEY_DEF_LEN    128
  17 #define  SERPENT_KEY_MAX_LEN    256
  18
  19 static void
  20 do_serpent(u_int8_t *buf, size_t buf_size, u_int8_t *key, size_t key_size, u_int8_t *iv, bool enc)
  21 {
  22     serpent_context serpent_ctx;
  23     char iv_bak[SERPENT_CBC_BLOCK_SIZE];
  24     char *new_iv = NULL;        /* logic will avoid copy to NULL */
  25
  26
  27     serpent_set_key(&serpent_ctx, key, key_size);
  28     /*
  29      *  my SERPENT 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,
  35                             (char*) buf + buf_size-SERPENT_CBC_BLOCK_SIZE,
  36                             SERPENT_CBC_BLOCK_SIZE);
  37
  38     serpent_cbc_encrypt(&serpent_ctx, buf, buf, buf_size, iv, enc);
  39
  40     if (enc)
  41             new_iv = (char*) buf + buf_size-SERPENT_CBC_BLOCK_SIZE;
  42
  43     memcpy(iv, new_iv, SERPENT_CBC_BLOCK_SIZE);
  44 }
  45
  46 struct encrypt_desc encrypt_desc_serpent =
  47 {
  48         algo_type:      IKE_ALG_ENCRYPT,
  49         algo_id:        OAKLEY_SERPENT_CBC,
  50         algo_next:      NULL,
  51         enc_ctxsize:    sizeof(struct serpent_context),
  52         enc_blocksize:  SERPENT_CBC_BLOCK_SIZE,
  53         keyminlen:      SERPENT_KEY_MIN_LEN,
  54         keydeflen:      SERPENT_KEY_DEF_LEN,
  55         keymaxlen:      SERPENT_KEY_MAX_LEN,
  56         do_crypt:       do_serpent,
  57 };
  58
  59 int ike_alg_serpent_init(void);
  60
  61 int
  62 ike_alg_serpent_init(void)
  63 {
  64     int ret = ike_alg_register_enc(&encrypt_desc_serpent);
  65
  66     return ret;
  67 }
  68 /*
  69 IKE_ALG_INIT_NAME: ike_alg_serpent_init
  70 */