view libtomcrypt/src/misc/compare_testvector.c @ 1790:42745af83b7d

Introduce extra delay before closing unauthenticated sessions To make it harder for attackers, introduce a delay to keep an unauthenticated session open a bit longer, thus blocking a connection slot until after the delay. Without this, while there is a limit on the amount of attempts an attacker can make at the same time (MAX_UNAUTH_PER_IP), the time taken by dropbear to handle one attempt is still short and thus for each of the allowed parallel attempts many attempts can be chained one after the other. The attempt rate is then: "MAX_UNAUTH_PER_IP / <process time of one attempt>". With the delay, this rate becomes: "MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".
author Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
date Wed, 15 Feb 2017 13:53:04 +0100
parents 6dba84798cd5
children
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */

#include "tomcrypt.h"

/**
  @file compare_testvector.c
  Function to compare two testvectors and print a (detailed) error-message if required, Steffen Jaeckel
*/

#if defined(LTC_TEST) && defined(LTC_TEST_DBG)
static void _print_hex(const char* what, const void* v, const unsigned long l)
{
  const unsigned char* p = v;
  unsigned long x, y = 0, z;
  fprintf(stderr, "%s contents: \n", what);
  for (x = 0; x < l; ) {
      fprintf(stderr, "%02X ", p[x]);
      if (!(++x % 16) || x == l) {
         if((x % 16) != 0) {
            z = 16 - (x % 16);
            if(z >= 8)
               fprintf(stderr, " ");
            for (; z != 0; --z) {
               fprintf(stderr, "   ");
            }
         }
         fprintf(stderr, " | ");
         for(; y < x; y++) {
            if((y % 8) == 0)
               fprintf(stderr, " ");
            if(isgraph(p[y]))
               fprintf(stderr, "%c", p[y]);
            else
               fprintf(stderr, ".");
         }
         fprintf(stderr, "\n");
      }
      else if((x % 8) == 0) {
         fprintf(stderr, " ");
      }
  }
}
#endif

/**
  Compare two test-vectors

  @param is             The data as it is
  @param is_len         The length of is
  @param should         The data as it should
  @param should_len     The length of should
  @param what           The type of the data
  @param which          The iteration count
  @return 0 on equality, -1 or 1 on difference
*/
int compare_testvector(const void* is, const unsigned long is_len, const void* should, const unsigned long should_len, const char* what, int which)
{
   int res = 0;
   if(is_len != should_len)
      res = is_len > should_len ? -1 : 1;
   else
      res = XMEMCMP(is, should, is_len);

#if defined(LTC_TEST) && defined(LTC_TEST_DBG)
   if (res != 0) {
      fprintf(stderr, "Testvector #%i of %s failed:\n", which, what);
      _print_hex("SHOULD", should, should_len);
      _print_hex("IS    ", is, is_len);
   }
#else
   LTC_UNUSED_PARAM(which);
   LTC_UNUSED_PARAM(what);
#endif

   return res;
}

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */