auth.c

srtp 1.0.1 比较适用于头一次看。其他版本的有需要也可以传上来。

/*
 * auth.c
 *
 * some bookkeeping functions for authentication functions
 *
 * David A. McGrew
 * Cisco Systems, Inc.
 */

/*
 *	
 * Copyright  (c) 2001, 2002, Cisco Systems, Inc.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 *   Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 * 
 *   Neither the name of the Cisco Systems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "auth.h"

#define PRINT_DEBUG  0    /* set to 1 to print debugging output */

#if PRINT_DEBUG
#include <stdio.h>
#endif 

inline int
auth_get_key_length(const auth_t *a) {
  return a->key_len;
}

inline int
auth_get_tag_length(const auth_t *a) {
  return a->out_len;
}

inline int
auth_type_get_ref_count(const auth_type_t *at) {
  return at->ref_count;
}

/*
 * auth_type_self_test() tests an auth function of type ct against
 * test cases provided in an array of values of key, data, and tag
 * that is known to be good
 */

#define SELF_TEST_TAG_BUF_OCTETS 16

err_status_t
auth_type_self_test(const auth_type_t *at) {
  auth_test_case_t *test_case = at->test_data;
  auth_t *a;
  err_status_t status;
  octet_t tag[SELF_TEST_TAG_BUF_OCTETS];
  int i, case_num = 0;

#if PRINT_DEBUG
  printf("running self-test for auth function %s\n", at->description);
#endif
  
  /* loop over all test cases */  
  while (test_case != NULL) {

    /* check test case parameters */
    if (test_case->tag_length_octets > SELF_TEST_TAG_BUF_OCTETS)
      return err_status_bad_param;
    
    /* allocate auth */
    status = auth_type_alloc(at, &a, test_case->key_length_octets,
			     test_case->tag_length_octets);
    if (status)
      return status;
    
    /* initialize auth */
    status = auth_init(a, test_case->key, test_case->key_length_octets);
    if (status) {
      auth_dealloc(a);
      return status;
    }

    /* zeroize tag then compute */
    octet_string_set_to_zero(tag, test_case->tag_length_octets);
    status = auth_compute(a, test_case->data,
			  test_case->data_length_octets, tag);
    if (status) {
      auth_dealloc(a);
      return status;
    }
    
#if PRINT_DEBUG
    printf("key: %s\n",
	   octet_string_hex_string(test_case->key,
				   2*test_case->key_length_octets));
    printf("data: %s\n",
	   octet_string_hex_string(test_case->data,
				   2*test_case->data_length_octets));
    printf("tag computed: %s\n",
	   octet_string_hex_string(tag, 2*test_case->tag_length_octets));
    printf("tag expected: %s\n",
	   octet_string_hex_string(test_case->tag,
				   2*test_case->tag_length_octets));
#endif

    /* check the result */
    status = err_status_ok;
    for (i=0; i < test_case->tag_length_octets; i++)
      if (tag[i] != test_case->tag[i]) {
	status = err_status_algo_fail;
#if PRINT_DEBUG
	printf("test case %d failed at byte %d\n", case_num, i);
#endif
      }
    if (status) {
      auth_dealloc(a);
      return err_status_algo_fail;
    }
    
    /* deallocate the auth function */
    status = auth_dealloc(a);
    if (status)
      return status;
    
    /* 
     * the auth function passed the test case, so move on to the next test
     * case in the list; if NULL, we'll quit and return an OK
     */   
    test_case = test_case->next_test_case;
    ++case_num;
  }
  
  return err_status_ok;
}