view libtomcrypt/tests/ecc_test.c @ 1788:1fc0012b9c38

Fix handling of replies to global requests (#112) The current code assumes that all global requests want / need a reply. This isn't always true and the request itself indicates if it wants a reply or not. It causes a specific problem with [email protected] messages. These are sent by OpenSSH after authentication to inform the client of potential other host keys for the host. This can be used to add a new type of host key or to rotate host keys. The initial information message from the server is sent as a global request, but with want_reply set to false. This means that the server doesn't expect an answer to this message. Instead the client needs to send a prove request as a reply if it wants to receive proof of ownership for the host keys. The bug doesn't cause any current problems with due to how OpenSSH treats receiving the failure message. It instead treats it as a keepalive message and further ignores it. Arguably this is a protocol violation though of Dropbear and it is only accidental that it doesn't cause a problem with OpenSSH. The bug was found when adding host keys support to libssh, which is more strict protocol wise and treats the unexpected failure message an error, also see https://gitlab.com/libssh/libssh-mirror/-/merge_requests/145 for more information. The fix here is to honor the want_reply flag in the global request and to only send a reply if the other side expects a reply.
author Dirkjan Bussink <d.bussink@gmail.com>
date Thu, 10 Dec 2020 16:13:13 +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_test.h>

#if defined(LTC_MECC) && defined(LTC_TEST_MPI)

static unsigned int sizes[] = {
#ifdef LTC_ECC112
14,
#endif
#ifdef LTC_ECC128
16,
#endif
#ifdef LTC_ECC160
20,
#endif
#ifdef LTC_ECC192
24,
#endif
#ifdef LTC_ECC224
28,
#endif
#ifdef LTC_ECC256
32,
#endif
#ifdef LTC_ECC384
48,
#endif
#ifdef LTC_ECC521
65
#endif
};

#ifdef LTC_ECC_SHAMIR
int ecc_test_shamir(void)
{
   void *modulus, *mp, *kA, *kB, *rA, *rB;
   ecc_point *G, *A, *B, *C1, *C2;
   int x, y, z;
   unsigned char buf[ECC_BUF_SIZE];

   DO(mp_init_multi(&kA, &kB, &rA, &rB, &modulus, NULL));
   LTC_ARGCHK((G  = ltc_ecc_new_point()) != NULL);
   LTC_ARGCHK((A  = ltc_ecc_new_point()) != NULL);
   LTC_ARGCHK((B  = ltc_ecc_new_point()) != NULL);
   LTC_ARGCHK((C1 = ltc_ecc_new_point()) != NULL);
   LTC_ARGCHK((C2 = ltc_ecc_new_point()) != NULL);

   for (x = 0; x < (int)(sizeof(sizes)/sizeof(sizes[0])); x++) {
       /* get the base point */
       for (z = 0; ltc_ecc_sets[z].name; z++) {
           if (sizes[z] < (unsigned int)ltc_ecc_sets[z].size) break;
       }
       LTC_ARGCHK(ltc_ecc_sets[z].name != NULL);

       /* load it */
       DO(mp_read_radix(G->x, ltc_ecc_sets[z].Gx, 16));
       DO(mp_read_radix(G->y, ltc_ecc_sets[z].Gy, 16));
       DO(mp_set(G->z, 1));
       DO(mp_read_radix(modulus, ltc_ecc_sets[z].prime, 16));
       DO(mp_montgomery_setup(modulus, &mp));

       /* do 100 random tests */
       for (y = 0; y < 100; y++) {
          /* pick a random r1, r2 */
          LTC_ARGCHK(yarrow_read(buf, sizes[x], &yarrow_prng) == sizes[x]);
          DO(mp_read_unsigned_bin(rA, buf, sizes[x]));
          LTC_ARGCHK(yarrow_read(buf, sizes[x], &yarrow_prng) == sizes[x]);
          DO(mp_read_unsigned_bin(rB, buf, sizes[x]));

          /* compute rA * G = A */
          DO(ltc_mp.ecc_ptmul(rA, G, A, modulus, 1));

          /* compute rB * G = B */
          DO(ltc_mp.ecc_ptmul(rB, G, B, modulus, 1));

          /* pick a random kA, kB */
          LTC_ARGCHK(yarrow_read(buf, sizes[x], &yarrow_prng) == sizes[x]);
          DO(mp_read_unsigned_bin(kA, buf, sizes[x]));
          LTC_ARGCHK(yarrow_read(buf, sizes[x], &yarrow_prng) == sizes[x]);
          DO(mp_read_unsigned_bin(kB, buf, sizes[x]));

          /* now, compute kA*A + kB*B = C1 using the older method */
          DO(ltc_mp.ecc_ptmul(kA, A, C1, modulus, 0));
          DO(ltc_mp.ecc_ptmul(kB, B, C2, modulus, 0));
          DO(ltc_mp.ecc_ptadd(C1, C2, C1, modulus, mp));
          DO(ltc_mp.ecc_map(C1, modulus, mp));

          /* now compute using mul2add */
          DO(ltc_mp.ecc_mul2add(A, kA, B, kB, C2, modulus));

          /* is they the sames?  */
          if ((mp_cmp(C1->x, C2->x) != LTC_MP_EQ) || (mp_cmp(C1->y, C2->y) != LTC_MP_EQ) || (mp_cmp(C1->z, C2->z) != LTC_MP_EQ)) {
             fprintf(stderr, "ECC failed shamir test: size=%d, testno=%d\n", sizes[x], y);
             return 1;
          }
      }
      mp_montgomery_free(mp);
  }
  ltc_ecc_del_point(C2);
  ltc_ecc_del_point(C1);
  ltc_ecc_del_point(B);
  ltc_ecc_del_point(A);
  ltc_ecc_del_point(G);
  mp_clear_multi(kA, kB, rA, rB, modulus, NULL);
  return 0;
}
#endif

int ecc_tests (void)
{
  unsigned char buf[4][4096], ch;
  unsigned long x, y, z, s;
  int           stat, stat2;
  ecc_key usera, userb, pubKey, privKey;

  DO(ecc_test ());

  for (s = 0; s < (sizeof(sizes)/sizeof(sizes[0])); s++) {
     /* make up two keys */
     DO(ecc_make_key (&yarrow_prng, find_prng ("yarrow"), sizes[s], &usera));
     DO(ecc_make_key (&yarrow_prng, find_prng ("yarrow"), sizes[s], &userb));

     /* make the shared secret */
     x = sizeof(buf[0]);
     DO(ecc_shared_secret (&usera, &userb, buf[0], &x));

     y = sizeof(buf[1]);
     DO(ecc_shared_secret (&userb, &usera, buf[1], &y));

     if (y != x) {
       fprintf(stderr, "ecc Shared keys are not same size.");
       return 1;
     }

     if (memcmp (buf[0], buf[1], x)) {
       fprintf(stderr, "ecc Shared keys not same contents.");
       return 1;
     }

     /* now export userb */
     y = sizeof(buf[0]);
     DO(ecc_export (buf[1], &y, PK_PUBLIC, &userb));
     ecc_free (&userb);

     /* import and make the shared secret again */
     DO(ecc_import (buf[1], y, &userb));

     z = sizeof(buf[0]);
     DO(ecc_shared_secret (&usera, &userb, buf[2], &z));

     if (z != x) {
       fprintf(stderr, "failed.  Size don't match?");
       return 1;
     }
     if (memcmp (buf[0], buf[2], x)) {
       fprintf(stderr, "Failed.  Contents didn't match.");
       return 1;
     }

     /* export with ANSI X9.63 */
     y = sizeof(buf[1]);
     DO(ecc_ansi_x963_export(&userb, buf[1], &y));
     ecc_free (&userb);

     /* now import the ANSI key */
     DO(ecc_ansi_x963_import(buf[1], y, &userb));

     /* shared secret */
     z = sizeof(buf[0]);
     DO(ecc_shared_secret (&usera, &userb, buf[2], &z));

     if (z != x) {
       fprintf(stderr, "failed.  Size don't match?");
       return 1;
     }
     if (memcmp (buf[0], buf[2], x)) {
       fprintf(stderr, "Failed.  Contents didn't match.");
       return 1;
     }

     ecc_free (&usera);
     ecc_free (&userb);

     /* test encrypt_key */
     DO(ecc_make_key (&yarrow_prng, find_prng ("yarrow"), sizes[s], &usera));

     /* export key */
     x = sizeof(buf[0]);
     DO(ecc_export(buf[0], &x, PK_PUBLIC, &usera));
     DO(ecc_import(buf[0], x, &pubKey));
     x = sizeof(buf[0]);
     DO(ecc_export(buf[0], &x, PK_PRIVATE, &usera));
     DO(ecc_import(buf[0], x, &privKey));

     for (ch = 0; ch < 32; ch++) {
        buf[0][ch] = ch;
     }
     y = sizeof (buf[1]);
     DO(ecc_encrypt_key (buf[0], 32, buf[1], &y, &yarrow_prng, find_prng ("yarrow"), find_hash ("sha256"), &pubKey));
     zeromem (buf[0], sizeof (buf[0]));
     x = sizeof (buf[0]);
     DO(ecc_decrypt_key (buf[1], y, buf[0], &x, &privKey));
     if (x != 32) {
       fprintf(stderr, "Failed (length)");
       return 1;
     }
     for (ch = 0; ch < 32; ch++) {
        if (buf[0][ch] != ch) {
           fprintf(stderr, "Failed (contents)");
           return 1;
        }
     }
     /* test sign_hash */
     for (ch = 0; ch < 16; ch++) {
        buf[0][ch] = ch;
     }
     x = sizeof (buf[1]);
     DO(ecc_sign_hash (buf[0], 16, buf[1], &x, &yarrow_prng, find_prng ("yarrow"), &privKey));
     DO(ecc_verify_hash (buf[1], x, buf[0], 16, &stat, &pubKey));
     buf[0][0] ^= 1;
     DO(ecc_verify_hash (buf[1], x, buf[0], 16, &stat2, &privKey));
     if (!(stat == 1 && stat2 == 0)) {
        fprintf(stderr, "ecc_verify_hash failed %d, %d, ", stat, stat2);
        return 1;
     }
     /* test sign_hash_rfc7518 */
     for (ch = 0; ch < 16; ch++) {
        buf[0][ch] = ch;
     }
     x = sizeof (buf[1]);
     DO(ecc_sign_hash_rfc7518(buf[0], 16, buf[1], &x, &yarrow_prng, find_prng ("yarrow"), &privKey));
     DO(ecc_verify_hash_rfc7518(buf[1], x, buf[0], 16, &stat, &pubKey));
     buf[0][0] ^= 1;
     DO(ecc_verify_hash_rfc7518(buf[1], x, buf[0], 16, &stat2, &privKey));
     if (!(stat == 1 && stat2 == 0)) {
        fprintf(stderr, "ecc_verify_hash_rfc7518 failed %d, %d, ", stat, stat2);
        return 1;
     }
     ecc_free (&usera);
     ecc_free (&pubKey);
     ecc_free (&privKey);
  }
#ifdef LTC_ECC_SHAMIR
  return ecc_test_shamir();
#else
  return 0;
#endif
}

#else

int ecc_tests(void)
{
   return CRYPT_NOP;
}

#endif

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