/* 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;
}
cdk_error_t _cdk_pubkey_compare(cdk_pkt_pubkey_t a, cdk_pkt_pubkey_t b)
{
int na, nb, i;
if (a->timestamp != b->timestamp
|| a->pubkey_algo != b->pubkey_algo)
return -1;
if (a->version < 4 && a->expiredate != b->expiredate)
return -1;
na = cdk_pk_get_npkey(a->pubkey_algo);
nb = cdk_pk_get_npkey(b->pubkey_algo);
if (na != nb)
return -1;
for (i = 0; i < na; i++) {
if (_gnutls_mpi_cmp(a->mpi[i], b->mpi[i]))
return -1;
}
return 0;
}
/* Check if N is a prime and G a generator of the
* group. This is check only done if N is big enough.
* Otherwise only the included parameters must be used.
*/
static int
group_check_g_n (mpi_t g, mpi_t n)
{
mpi_t q = NULL, two = NULL, w = NULL;
int ret;
if (_gnutls_mpi_get_nbits (n) < 2048)
{
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
/* N must be of the form N=2q+1
* where q is also a prime.
*/
if (_gnutls_prime_check (n, 0) != 0)
{
_gnutls_dump_mpi ("no prime N: ", n);
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
two = _gnutls_mpi_new (4);
if (two == NULL)
{
gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
q = _gnutls_mpi_alloc_like (n);
if (q == NULL)
{
gnutls_assert ();
ret = GNUTLS_E_MEMORY_ERROR;
goto error;
}
/* q = n-1
*/
_gnutls_mpi_sub_ui (q, n, 1);
/* q = q/2, remember that q is divisible by 2 (prime - 1)
*/
_gnutls_mpi_set_ui (two, 2);
_gnutls_mpi_div (q, NULL, q, two, 0);
if (_gnutls_prime_check (q, 0) != 0)
{
/* N was not on the form N=2q+1, where q = prime
*/
_gnutls_dump_mpi ("no prime Q: ", q);
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
/* We also check whether g is a generator,
*/
/* check if g < q < N
*/
if (_gnutls_mpi_cmp (g, q) >= 0)
{
gnutls_assert ();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
w = _gnutls_mpi_alloc_like (q);
if (w == NULL)
{
gnutls_assert ();
ret = GNUTLS_E_MEMORY_ERROR;
goto error;
}
/* check if g^q mod N == N-1
* w = g^q mod N
*/
_gnutls_mpi_powm (w, g, q, n);
/* w++
*/
_gnutls_mpi_add_ui (w, w, 1);
if (_gnutls_mpi_cmp (w, n) != 0)
{
gnutls_assert ();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
ret = 0;
error:
_gnutls_mpi_release (&q);
_gnutls_mpi_release (&two);
_gnutls_mpi_release (&w);
return ret;
}
/* Check if N is a prime and G a generator of the
* group. This check is only done if N is big enough.
* Otherwise only the included parameters must be used.
*/
static int
group_check_g_n(gnutls_session_t session, bigint_t g, bigint_t n)
{
bigint_t q = NULL, two = NULL, w = NULL;
int ret;
if (_gnutls_mpi_get_nbits(n) < (session->internals.srp_prime_bits
? session->internals.srp_prime_bits
: 2048)) {
gnutls_assert();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
/* N must be of the form N=2q+1
* where q is also a prime.
*/
if (_gnutls_prime_check(n) != 0) {
_gnutls_mpi_log("no prime N: ", n);
gnutls_assert();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
ret = _gnutls_mpi_init_multi(&two, &q, &w, NULL);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* q = n-1
*/
ret = _gnutls_mpi_sub_ui(q, n, 1);
if (ret < 0) {
gnutls_assert();
goto error;
}
/* q = q/2, remember that q is divisible by 2 (prime - 1)
*/
ret = _gnutls_mpi_set_ui(two, 2);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_div(q, q, two);
if (ret < 0) {
gnutls_assert();
goto error;
}
if (_gnutls_prime_check(q) != 0) {
/* N was not on the form N=2q+1, where q = prime
*/
_gnutls_mpi_log("no prime Q: ", q);
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
/* We also check whether g is a generator,
*/
/* check if g < q < N
*/
if (_gnutls_mpi_cmp(g, q) >= 0) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
/* check if g^q mod N == N-1
* w = g^q mod N
*/
ret = _gnutls_mpi_powm(w, g, q, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
/* w++
*/
ret = _gnutls_mpi_add_ui(w, w, 1);
if (ret < 0) {
gnutls_assert();
goto error;
}
if (_gnutls_mpi_cmp(w, n) != 0) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
ret = 0;
error:
_gnutls_mpi_release(&q);
_gnutls_mpi_release(&two);
_gnutls_mpi_release(&w);
return ret;
}
static int
wrap_nettle_pk_verify_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);
t1 = _gnutls_mpi_new (256);
if (t1 == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
_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);
t2 = _gnutls_mpi_mod (params->params[RSA_PRIV], t1);
if (t2 == NULL)
{
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);
_gnutls_mpi_release(&t2);
t2 = _gnutls_mpi_mod (params->params[RSA_PRIV], t1);
if (t2 == NULL)
{
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:
_gnutls_mpi_release(&t1);
_gnutls_mpi_release(&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);
t1 = _gnutls_mpi_new (256);
if (t1 == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
_gnutls_mpi_powm (t1, params->params[DSA_G], params->params[DSA_X], params->params[DSA_P]);
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:
_gnutls_mpi_release(&t1);
}
break;
case GNUTLS_PK_EC:
{
int curve = params->flags;
ecc_key ecc_priv;
ecc_point *R;
ecc_point zero;
if (params->params_nr != ECC_PRIVATE_PARAMS)
return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
if (is_supported_curve(curve) == 0)
return gnutls_assert_val(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
_ecc_params_to_privkey(params, &ecc_priv);
R = ecc_new_point();
/* verify that x,y lie on the curve */
ret = ecc_projective_check_point(&ecc_priv.pubkey, TOMPZ(params->params[ECC_B]), params->params[ECC_PRIME]);
if (ret != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
memcpy(&zero.x, ecc_priv.Gx, sizeof(mpz_t));
memcpy(&zero.y, ecc_priv.Gy, sizeof(mpz_t));
memcpy(&zero.z, ecc_priv.pubkey.z, sizeof(mpz_t)); /* z = 1 */
/* verify that k*(Gx,Gy)=(x,y) */
ret = ecc_mulmod_cached(ecc_priv.k, curve, R, TOMPZ(params->params[ECC_A]), TOMPZ(params->params[ECC_PRIME]), 1);
if (ret != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
if (mpz_cmp(ecc_priv.pubkey.x, R->x) != 0 || mpz_cmp(ecc_priv.pubkey.y, R->y) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
ret = 0;
ecc_cleanup:
_ecc_params_clear(&ecc_priv);
ecc_del_point(R);
}
break;
default:
ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
}
return ret;
}
static int
wrap_nettle_pk_verify_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);
t1 = _gnutls_mpi_new(256);
if (t1 == NULL)
return
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
_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);
t2 = _gnutls_mpi_mod(params->params[RSA_PRIV], t1);
if (t2 == NULL) {
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);
_gnutls_mpi_release(&t2);
t2 = _gnutls_mpi_mod(params->params[RSA_PRIV], t1);
if (t2 == NULL) {
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:
_gnutls_mpi_release(&t1);
_gnutls_mpi_release(&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);
t1 = _gnutls_mpi_new(256);
if (t1 == NULL)
return
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
_gnutls_mpi_powm(t1, params->params[DSA_G],
params->params[DSA_X],
params->params[DSA_P]);
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:
_gnutls_mpi_release(&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_clear(&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_clear(&priv);
ecc_point_clear(&pub);
}
break;
default:
ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
}
return ret;
}
/* 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;
}
