static int calc_rsa_exp(gnutls_pk_params_st * params)
{
bigint_t tmp;
int ret;
if (params->params_nr < RSA_PRIVATE_PARAMS - 2) {
gnutls_assert();
return GNUTLS_E_INTERNAL_ERROR;
}
params->params[6] = params->params[7] = NULL;
ret = _gnutls_mpi_init_multi(&tmp, ¶ms->params[6], ¶ms->params[7], NULL);
if (ret < 0)
return gnutls_assert_val(ret);
/* [6] = d % p-1, [7] = d % q-1 */
_gnutls_mpi_sub_ui(tmp, params->params[3], 1);
ret =
_gnutls_mpi_modm(params->params[6], params->params[2] /*d */ , tmp);
if (ret < 0)
goto fail;
_gnutls_mpi_sub_ui(tmp, params->params[4], 1);
ret =
_gnutls_mpi_modm(params->params[7], params->params[2] /*d */ , tmp);
if (ret < 0)
goto fail;
zrelease_mpi_key(&tmp);
return 0;
fail:
zrelease_mpi_key(&tmp);
zrelease_mpi_key(¶ms->params[6]);
zrelease_mpi_key(¶ms->params[7]);
return ret;
}
/* Checks if a%n==0,+1,-1%n which is a fatal srp error.
* Returns a proper error code in that case, and 0 when
* all are ok.
*/
inline static int check_param_mod_n(bigint_t a, bigint_t n, int is_a)
{
int ret, err = 0;
bigint_t r;
ret = _gnutls_mpi_init(&r);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _gnutls_mpi_modm(r, a, n);
if (ret < 0) {
_gnutls_mpi_release(&r);
return gnutls_assert_val(ret);
}
ret = _gnutls_mpi_cmp_ui(r, 0);
if (ret == 0)
err = 1;
if (is_a != 0) {
ret = _gnutls_mpi_cmp_ui(r, 1);
if (ret == 0)
err = 1;
ret = _gnutls_mpi_add_ui(r, r, 1);
if (ret < 0) {
_gnutls_mpi_release(&r);
return gnutls_assert_val(ret);
}
ret = _gnutls_mpi_cmp(r, n);
if (ret == 0)
err = 1;
}
_gnutls_mpi_release(&r);
if (err != 0) {
gnutls_assert();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
return 0;
}
/* This is used for DH or ECDH key derivation. In DH for example
* it is given the peers Y and our x, and calculates Y^x
*/
static int _wrap_nettle_pk_derive(gnutls_pk_algorithm_t algo,
gnutls_datum_t * out,
const gnutls_pk_params_st * priv,
const gnutls_pk_params_st * pub)
{
int ret;
switch (algo) {
case GNUTLS_PK_DH: {
bigint_t f, x, prime;
bigint_t k = NULL, ff = NULL;
unsigned int bits;
f = pub->params[DH_Y];
x = priv->params[DH_X];
prime = priv->params[DH_P];
ret = _gnutls_mpi_init_multi(&k, &ff, NULL);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _gnutls_mpi_modm(ff, f, prime);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
ret = _gnutls_mpi_add_ui(ff, ff, 1);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
/* check if f==0,1,p-1.
* or (ff=f+1) equivalently ff==1,2,p */
if ((_gnutls_mpi_cmp_ui(ff, 2) == 0)
|| (_gnutls_mpi_cmp_ui(ff, 1) == 0)
|| (_gnutls_mpi_cmp(ff, prime) == 0)) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto dh_cleanup;
}
/* prevent denial of service */
bits = _gnutls_mpi_get_nbits(prime);
if (bits == 0 || bits > MAX_DH_BITS) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto dh_cleanup;
}
ret = _gnutls_mpi_powm(k, f, x, prime);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
ret = _gnutls_mpi_dprint(k, out);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
ret = 0;
dh_cleanup:
_gnutls_mpi_release(&ff);
zrelease_temp_mpi_key(&k);
if (ret < 0)
goto cleanup;
break;
}
case GNUTLS_PK_EC:
{
struct ecc_scalar ecc_priv;
struct ecc_point ecc_pub;
const struct ecc_curve *curve;
out->data = NULL;
curve = get_supported_curve(priv->flags);
if (curve == NULL)
return
gnutls_assert_val
(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
ret = _ecc_params_to_pubkey(pub, &ecc_pub, curve);
if (ret < 0)
return gnutls_assert_val(ret);
ret =
_ecc_params_to_privkey(priv, &ecc_priv, curve);
if (ret < 0) {
ecc_point_clear(&ecc_pub);
return gnutls_assert_val(ret);
}
out->size = gnutls_ecc_curve_get_size(priv->flags);
/*ecc_size(curve)*sizeof(mp_limb_t); */
out->data = gnutls_malloc(out->size);
if (out->data == NULL) {
ret =
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
goto ecc_cleanup;
}
ecc_shared_secret(&ecc_priv, &ecc_pub, out->data,
out->size);
ecc_cleanup:
ecc_point_clear(&ecc_pub);
ecc_scalar_zclear(&ecc_priv);
if (ret < 0)
goto cleanup;
break;
}
default:
gnutls_assert();
ret = GNUTLS_E_INTERNAL_ERROR;
goto cleanup;
}
ret = 0;
cleanup:
return ret;
}
static int
wrap_nettle_pk_verify_priv_params(gnutls_pk_algorithm_t algo,
const gnutls_pk_params_st * params)
{
int ret;
switch (algo) {
case GNUTLS_PK_RSA:
{
bigint_t t1 = NULL, t2 = NULL;
if (params->params_nr != RSA_PRIVATE_PARAMS)
return
gnutls_assert_val
(GNUTLS_E_INVALID_REQUEST);
ret = _gnutls_mpi_init_multi(&t1, &t2, NULL);
if (ret < 0)
return
gnutls_assert_val(ret);
_gnutls_mpi_mulm(t1, params->params[RSA_PRIME1],
params->params[RSA_PRIME2],
params->params[RSA_MODULUS]);
if (_gnutls_mpi_cmp_ui(t1, 0) != 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
mpz_invert(TOMPZ(t1),
TOMPZ(params->params[RSA_PRIME2]),
TOMPZ(params->params[RSA_PRIME1]));
if (_gnutls_mpi_cmp(t1, params->params[RSA_COEF])
!= 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
/* [RSA_PRIME1] = d % p-1, [RSA_PRIME2] = d % q-1 */
_gnutls_mpi_sub_ui(t1, params->params[RSA_PRIME1],
1);
ret = _gnutls_mpi_modm(t2, params->params[RSA_PRIV], t1);
if (ret < 0) {
ret =
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
goto rsa_cleanup;
}
if (_gnutls_mpi_cmp(params->params[RSA_E1], t2) !=
0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
_gnutls_mpi_sub_ui(t1, params->params[RSA_PRIME2],
1);
ret = _gnutls_mpi_modm(t2, params->params[RSA_PRIV], t1);
if (ret < 0) {
ret =
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
goto rsa_cleanup;
}
if (_gnutls_mpi_cmp(params->params[RSA_E2], t2) !=
0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
ret = 0;
rsa_cleanup:
zrelease_mpi_key(&t1);
zrelease_mpi_key(&t2);
}
break;
case GNUTLS_PK_DSA:
{
bigint_t t1 = NULL;
if (params->params_nr != DSA_PRIVATE_PARAMS)
return
gnutls_assert_val
(GNUTLS_E_INVALID_REQUEST);
ret = _gnutls_mpi_init(&t1);
if (ret < 0)
return
gnutls_assert_val(ret);
ret = _gnutls_mpi_powm(t1, params->params[DSA_G],
params->params[DSA_X],
params->params[DSA_P]);
if (ret < 0) {
gnutls_assert();
goto dsa_cleanup;
}
if (_gnutls_mpi_cmp(t1, params->params[DSA_Y]) !=
0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto dsa_cleanup;
}
ret = 0;
dsa_cleanup:
zrelease_mpi_key(&t1);
}
break;
case GNUTLS_PK_EC:
{
struct ecc_point r, pub;
struct ecc_scalar priv;
mpz_t x1, y1, x2, y2;
const struct ecc_curve *curve;
if (params->params_nr != ECC_PRIVATE_PARAMS)
return
gnutls_assert_val
(GNUTLS_E_INVALID_REQUEST);
curve = get_supported_curve(params->flags);
if (curve == NULL)
return
gnutls_assert_val
(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
ret = _ecc_params_to_pubkey(params, &pub, curve);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _ecc_params_to_privkey(params, &priv, curve);
if (ret < 0) {
ecc_point_clear(&pub);
return gnutls_assert_val(ret);
}
ecc_point_init(&r, curve);
/* verify that x,y lie on the curve */
ret =
ecc_point_set(&r, TOMPZ(params->params[ECC_X]),
TOMPZ(params->params[ECC_Y]));
if (ret == 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
ecc_point_clear(&r);
ecc_point_init(&r, curve);
ecc_point_mul_g(&r, &priv);
mpz_init(x1);
mpz_init(y1);
ecc_point_get(&r, x1, y1);
ecc_point_zclear(&r);
mpz_init(x2);
mpz_init(y2);
ecc_point_get(&pub, x2, y2);
/* verify that k*(Gx,Gy)=(x,y) */
if (mpz_cmp(x1, x2) != 0 || mpz_cmp(y1, y2) != 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
ret = 0;
ecc_cleanup:
ecc_scalar_zclear(&priv);
ecc_point_clear(&pub);
}
break;
default:
ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
}
return ret;
}