Commit 0e71be5d authored by George Kadianakis's avatar George Kadianakis
Browse files

Improve code in the dynamic primes realm.

parent fb38e58d

src/common/crypto.c

+41 −46
Original line number Diff line number Diff line
@@ -1825,27 +1825,28 @@ static BIGNUM *dh_param_g = NULL; 
static BIGNUM *

crypto_generate_dynamic_prime(void)

{

  BIGNUM *dynamic_prime, *misc;

  BIGNUM *dynamic_prime;

  DH *dh_parameters;

  int r;

  int dh_codes;

  int r, dh_codes;

  char *s;



  dh_parameters = DH_new();

  dynamic_prime = BN_new();

  misc = BN_new();



  tor_assert(dynamic_prime);

  dh_parameters = DH_generate_parameters(DH_BYTES*8, DH_GENERATOR, NULL, NULL); // XXX Do we want a pretty call back?



  dh_parameters = DH_generate_parameters(DH_BYTES*8, DH_GENERATOR, NULL, NULL);

  tor_assert(dh_parameters);



  r = DH_check(dh_parameters, &dh_codes);

  tor_assert(r);

  misc = BN_copy(dynamic_prime, dh_parameters->p);

  tor_assert(misc);



  BN_copy(dynamic_prime, dh_parameters->p);

  tor_assert(dynamic_prime);



  DH_free(dh_parameters);



  {

  { /* log the dynamic prime: */

    s = BN_bn2hex(dynamic_prime);

    tor_assert(s);

    log_notice(LD_OR, "Dynamic prime generated: [%s]", s);

    OPENSSL_free(s);

  }
@@ -1858,62 +1859,56 @@ crypto_generate_dynamic_prime(void) 
static void

init_dh_param(void)

{

  BIGNUM *dynamic_prime, *p, *p2, *g;

  BIGNUM *circuit_dh_prime, *tls_prime, *generator;

  int r;

  if (dh_param_p && dh_param_g && dh_param_p_tls)

    return;



  dynamic_prime = BN_new();

  p = BN_new();

  p2 = BN_new();

  g = BN_new();

  tor_assert(dynamic_prime);

  tor_assert(p);

  tor_assert(p2);

  tor_assert(g);

  circuit_dh_prime = BN_new();

  generator = BN_new();

  tor_assert(circuit_dh_prime && generator);



  /* Set our generator for all DH parameters */

  r = BN_set_word(g, DH_GENERATOR);

  r = BN_set_word(generator, DH_GENERATOR);

  tor_assert(r);



  /* This implements the prime number strategy outlined in prop 179 */

  if (use_dynamic_primes) {

    log_notice(LD_OR, "Generating fresh dynamic prime.");

    dynamic_prime = crypto_generate_dynamic_prime();

  }



  /* This is from rfc2409, section 6.2.  It's a safe prime, and

     supposedly it equals:

        2^1024 - 2^960 - 1 + 2^64 * { [2^894 pi] + 129093 }.

  */

  r = BN_hex2bn(&p,

  r = BN_hex2bn(&circuit_dh_prime,

                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"

                "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"

                "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9"

                "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6"

                "49286651ECE65381FFFFFFFFFFFFFFFF");

  tor_assert(r);



  if (use_dynamic_primes) { /* use dynamic primes: */

    log_notice(LD_OR, "Generating fresh dynamic prime.");

    tls_prime = crypto_generate_dynamic_prime();

    tor_assert(tls_prime);

  } else { /* use the static DH prime modulus used by Apache in mod_ssl: */

    tls_prime = BN_new();

    tor_assert(tls_prime);



    /* This is the 1024-bit safe prime that Apache uses for its DH stuff; see

     * modules/ssl/ssl_engine_dh.c; Apache also uses a generator of 2 with this

     * prime.

     */

  r = BN_hex2bn(&p2,

    r = BN_hex2bn(&tls_prime,

                  "D67DE440CBBBDC1936D693D34AFD0AD50C84D239A45F520BB88174CB98"

                  "BCE951849F912E639C72FB13B4B4D7177E16D55AC179BA420B2A29FE324A"

                  "467A635E81FF5901377BEDDCFD33168A461AAD3B72DAE8860078045B07A7"

                  "DBCA7874087D1510EA9FCC9DDD330507DD62DB88AEAA747DE0F4D6E2BD68"

                  "B0E7393E0F24218EB3");

    tor_assert(r);



  r = BN_set_word(g, 2);

  tor_assert(r);

  dh_param_p = p;

  if (use_dynamic_primes) {

    dh_param_p_tls = dynamic_prime;

  } else {

    dh_param_p_tls = p2;

  }

  dh_param_g = g;



  /* Set the new values as the global DH parameters. */

  dh_param_p = circuit_dh_prime;

  dh_param_p_tls = tls_prime;

  dh_param_g = generator;

}



/** Number of bits to use when choosing the x or y value in a Diffie-Hellman