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      1 /*
      2  * null_auth.c
      3  *
      4  * implements the do-nothing auth algorithm
      5  *
      6  * David A. McGrew
      7  * Cisco Systems, Inc.
      8  *
      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 
     48 #include "null_auth.h"
     49 #include "alloc.h"
     50 
     51 /* null_auth uses the auth debug module */
     52 
     53 extern debug_module_t mod_auth;
     54 
     55 err_status_t
     56 null_auth_alloc(auth_t **a, int key_len, int out_len) {
     57   extern auth_type_t null_auth;
     58   uint8_t *pointer;
     59 
     60   debug_print(mod_auth, "allocating auth func with key length %d", key_len);
     61   debug_print(mod_auth, "                          tag length %d", out_len);
     62 
     63   /* allocate memory for auth and null_auth_ctx_t structures */
     64   pointer = (uint8_t*)crypto_alloc(sizeof(null_auth_ctx_t) + sizeof(auth_t));
     65   if (pointer == NULL)
     66     return err_status_alloc_fail;
     67 
     68   /* set pointers */
     69   *a = (auth_t *)pointer;
     70   (*a)->type = &null_auth;
     71   (*a)->state = pointer + sizeof (auth_t);
     72   (*a)->out_len = out_len;
     73   (*a)->prefix_len = out_len;
     74   (*a)->key_len = key_len;
     75 
     76   /* increment global count of all null_auth uses */
     77   null_auth.ref_count++;
     78 
     79   return err_status_ok;
     80 }
     81 
     82 err_status_t
     83 null_auth_dealloc(auth_t *a) {
     84   extern auth_type_t null_auth;
     85 
     86   /* zeroize entire state*/
     87   octet_string_set_to_zero((uint8_t *)a,
     88 			   sizeof(null_auth_ctx_t) + sizeof(auth_t));
     89 
     90   /* free memory */
     91   crypto_free(a);
     92 
     93   /* decrement global count of all null_auth uses */
     94   null_auth.ref_count--;
     95 
     96   return err_status_ok;
     97 }
     98 
     99 err_status_t
    100 null_auth_init(null_auth_ctx_t *state, const uint8_t *key, int key_len) {
    101 
    102   /* accept any length of key, and do nothing */
    103 
    104   return err_status_ok;
    105 }
    106 
    107 err_status_t
    108 null_auth_compute(null_auth_ctx_t *state, uint8_t *message,
    109 		   int msg_octets, int tag_len, uint8_t *result) {
    110 
    111   return err_status_ok;
    112 }
    113 
    114 err_status_t
    115 null_auth_update(null_auth_ctx_t *state, uint8_t *message,
    116 		   int msg_octets) {
    117 
    118   return err_status_ok;
    119 }
    120 
    121 err_status_t
    122 null_auth_start(null_auth_ctx_t *state) {
    123   return err_status_ok;
    124 }
    125 
    126 /*
    127  * auth_type_t - defines description, test case, and null_auth
    128  * metaobject
    129  */
    130 
    131 /* begin test case 0 */
    132 
    133 auth_test_case_t
    134 null_auth_test_case_0 = {
    135   0,                                       /* octets in key            */
    136   NULL,                                    /* key                      */
    137   0,                                       /* octets in data           */
    138   NULL,                                    /* data                     */
    139   0,                                       /* octets in tag            */
    140   NULL,                                    /* tag                      */
    141   NULL                                     /* pointer to next testcase */
    142 };
    143 
    144 /* end test case 0 */
    145 
    146 char null_auth_description[] = "null authentication function";
    147 
    148 auth_type_t
    149 null_auth  = {
    150   (auth_alloc_func)      null_auth_alloc,
    151   (auth_dealloc_func)    null_auth_dealloc,
    152   (auth_init_func)       null_auth_init,
    153   (auth_compute_func)    null_auth_compute,
    154   (auth_update_func)     null_auth_update,
    155   (auth_start_func)      null_auth_start,
    156   (char *)               null_auth_description,
    157   (int)                  0,  /* instance count */
    158   (auth_test_case_t *)   &null_auth_test_case_0,
    159   (debug_module_t *)     NULL,
    160   (auth_type_id_t)       NULL_AUTH
    161 };
    162 
    163