view libtomcrypt/tests/prng_test.c @ 1861:2b3a8026a6ce

Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
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_test.h>

#ifdef LTC_PRNG_ENABLE_LTC_RNG

static unsigned long my_test_rng_read;

static unsigned long my_test_rng(unsigned char *buf, unsigned long len,
                             void (*callback)(void))
{
   unsigned long n;
   LTC_UNUSED_PARAM(callback);
   for (n = 0; n < len; ++n) {
      buf[n] = 4;
   }
   my_test_rng_read += n;
   return n;
}

#endif

int prng_test(void)
{
   int           err = CRYPT_NOP;
   int           x;
   unsigned char buf[4096] = { 0 };
   unsigned long n, one;
   prng_state    nprng;

#ifdef LTC_PRNG_ENABLE_LTC_RNG
   unsigned long before;

   unsigned long (*previous)(unsigned char *, unsigned long , void (*)(void)) = ltc_rng;
   ltc_rng = my_test_rng;

   before = my_test_rng_read;

   if ((err = rng_make_prng(128, find_prng("yarrow"), &yarrow_prng, NULL)) != CRYPT_OK) {
      fprintf(stderr, "rng_make_prng with 'my_test_rng' failed: %s\n", error_to_string(err));
      exit(EXIT_FAILURE);
   }

   if (before == my_test_rng_read) {
      fprintf(stderr, "somehow there was no read from the ltc_rng! %lu == %lu\n", before, my_test_rng_read);
      exit(EXIT_FAILURE);
   }

   ltc_rng = previous;
#endif

   /* test prngs (test, import/export) */
   for (x = 0; prng_descriptor[x].name != NULL; x++) {
      if(strstr(prng_descriptor[x].name, "no_prng") == prng_descriptor[x].name) continue;
      err = CRYPT_OK;
      DOX(prng_descriptor[x].test(), prng_descriptor[x].name);
      DOX(prng_descriptor[x].start(&nprng), prng_descriptor[x].name);
      DOX(prng_descriptor[x].add_entropy((unsigned char *)"helloworld12", 12, &nprng), prng_descriptor[x].name);
      DOX(prng_descriptor[x].ready(&nprng), prng_descriptor[x].name);
      n = sizeof(buf);
      if (strcmp(prng_descriptor[x].name, "sprng")) {
         one = 1;
         if (prng_descriptor[x].pexport(buf, &one, &nprng) != CRYPT_BUFFER_OVERFLOW) {
            fprintf(stderr, "Error testing pexport with a short buffer (%s)\n", prng_descriptor[x].name);
            return CRYPT_ERROR;
         }
      }
      DOX(prng_descriptor[x].pexport(buf, &n, &nprng), prng_descriptor[x].name);
      prng_descriptor[x].done(&nprng);
      DOX(prng_descriptor[x].pimport(buf, n, &nprng), prng_descriptor[x].name);
      DOX(prng_descriptor[x].pimport(buf, 4096, &nprng), prng_descriptor[x].name); /* try to import larger data */
      DOX(prng_descriptor[x].ready(&nprng), prng_descriptor[x].name);
      if (prng_descriptor[x].read(buf, 100, &nprng) != 100) {
         fprintf(stderr, "Error reading from imported PRNG (%s)!\n", prng_descriptor[x].name);
         return CRYPT_ERROR;
      }
      prng_descriptor[x].done(&nprng);
   }
   return err;
}

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