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      1 /*
      2  * null_cipher.c
      3  *
      4  * A null cipher implementation.  This cipher leaves the plaintext
      5  * unchanged.
      6  *
      7  * David A. McGrew
      8  * Cisco Systems, Inc.
      9  */
     10 
     11 /*
     12  *
     13  * Copyright (c) 2001-2006, Cisco Systems, Inc.
     14  * All rights reserved.
     15  *
     16  * Redistribution and use in source and binary forms, with or without
     17  * modification, are permitted provided that the following conditions
     18  * are met:
     19  *
     20  *   Redistributions of source code must retain the above copyright
     21  *   notice, this list of conditions and the following disclaimer.
     22  *
     23  *   Redistributions in binary form must reproduce the above
     24  *   copyright notice, this list of conditions and the following
     25  *   disclaimer in the documentation and/or other materials provided
     26  *   with the distribution.
     27  *
     28  *   Neither the name of the Cisco Systems, Inc. nor the names of its
     29  *   contributors may be used to endorse or promote products derived
     30  *   from this software without specific prior written permission.
     31  *
     32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     35  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     36  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
     37  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     38  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     39  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     40  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     41  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     42  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     43  * OF THE POSSIBILITY OF SUCH DAMAGE.
     44  *
     45  */
     46 
     47 #include "datatypes.h"
     48 #include "null_cipher.h"
     49 #include "alloc.h"
     50 
     51 /* the null_cipher uses the cipher debug module  */
     52 
     53 extern debug_module_t mod_cipher;
     54 
     55 err_status_t
     56 null_cipher_alloc(cipher_t **c, int key_len) {
     57   extern cipher_type_t null_cipher;
     58   uint8_t *pointer;
     59 
     60   debug_print(mod_cipher,
     61 	      "allocating cipher with key length %d", key_len);
     62 
     63   /* allocate memory a cipher of type null_cipher */
     64   pointer = (uint8_t*)crypto_alloc(sizeof(null_cipher_ctx_t) + sizeof(cipher_t));
     65   if (pointer == NULL)
     66     return err_status_alloc_fail;
     67 
     68   /* set pointers */
     69   *c = (cipher_t *)pointer;
     70   (*c)->type = &null_cipher;
     71   (*c)->state = pointer + sizeof(cipher_t);
     72 
     73   /* set key size */
     74   (*c)->key_len = key_len;
     75 
     76   /* increment ref_count */
     77   null_cipher.ref_count++;
     78 
     79   return err_status_ok;
     80 
     81 }
     82 
     83 err_status_t
     84 null_cipher_dealloc(cipher_t *c) {
     85   extern cipher_type_t null_cipher;
     86 
     87   /* zeroize entire state*/
     88   octet_string_set_to_zero((uint8_t *)c,
     89 			   sizeof(null_cipher_ctx_t) + sizeof(cipher_t));
     90 
     91   /* free memory of type null_cipher */
     92   crypto_free(c);
     93 
     94   /* decrement reference count */
     95   null_cipher.ref_count--;
     96 
     97   return err_status_ok;
     98 
     99 }
    100 
    101 err_status_t
    102 null_cipher_init(null_cipher_ctx_t *ctx, const uint8_t *key) {
    103 
    104   debug_print(mod_cipher, "initializing null cipher", NULL);
    105 
    106   return err_status_ok;
    107 }
    108 
    109 err_status_t
    110 null_cipher_set_iv(null_cipher_ctx_t *c, void *iv) {
    111   return err_status_ok;
    112 }
    113 
    114 err_status_t
    115 null_cipher_encrypt(null_cipher_ctx_t *c,
    116 		    unsigned char *buf, unsigned int *bytes_to_encr) {
    117   return err_status_ok;
    118 }
    119 
    120 char
    121 null_cipher_description[] = "null cipher";
    122 
    123 cipher_test_case_t
    124 null_cipher_test_0 = {
    125   0,                 /* octets in key            */
    126   NULL,              /* key                      */
    127   0,                 /* packet index             */
    128   0,                 /* octets in plaintext      */
    129   NULL,              /* plaintext                */
    130   0,                 /* octets in plaintext      */
    131   NULL,              /* ciphertext               */
    132   NULL               /* pointer to next testcase */
    133 };
    134 
    135 
    136 /*
    137  * note: the decrypt function is idential to the encrypt function
    138  */
    139 
    140 cipher_type_t null_cipher = {
    141   (cipher_alloc_func_t)         null_cipher_alloc,
    142   (cipher_dealloc_func_t)       null_cipher_dealloc,
    143   (cipher_init_func_t)          null_cipher_init,
    144   (cipher_encrypt_func_t)       null_cipher_encrypt,
    145   (cipher_decrypt_func_t)       null_cipher_encrypt,
    146   (cipher_set_iv_func_t)        null_cipher_set_iv,
    147   (char *)                      null_cipher_description,
    148   (int)                         0,
    149   (cipher_test_case_t *)       &null_cipher_test_0,
    150   (debug_module_t *)            NULL
    151 };
    152 
    153