view libtomcrypt/tests/prng_test.c @ 1930:299f4f19ba19

Add /usr/sbin and /sbin to default root PATH When dropbear is used in a very restricted environment (such as in a initrd), the default user shell is often also very restricted and doesn't take care of setting the PATH so the user ends up with the PATH set by dropbear. Unfortunately, dropbear always sets "/usr/bin:/bin" as default PATH even for the root user which should have /usr/sbin and /sbin too. For a concrete instance of this problem, see the "Remote Unlocking" section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/ It speaks of a bug in the initramfs script because it's written "blkid" instead of "/sbin/blkid"... this is just because the scripts from the initramfs do not expect to have a PATH without the sbin directories and because dropbear is not setting the PATH appropriately for the root user. I'm thus suggesting to use the attached patch to fix this misbehaviour (I did not test it, but it's easy enough). It might seem anecdotic but multiple Kali users have been bitten by this. From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
author Raphael Hertzog <hertzog@debian.org>
date Mon, 09 Jul 2018 16:27:53 +0200
parents 6dba84798cd5
children
line wrap: on
line source

/* 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;
}

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