static int ec_bits(const EVP_PKEY *pkey) {
const EC_GROUP *group = EC_KEY_get0_group(pkey->pkey.ec);
if (group == NULL) {
ERR_clear_error();
return 0;
}
return BN_num_bits(EC_GROUP_get0_order(group));
}
int ec_key_simple_generate_key(EC_KEY *eckey)
{
int ok = 0;
BN_CTX *ctx = NULL;
BIGNUM *priv_key = NULL;
const BIGNUM *order = NULL;
EC_POINT *pub_key = NULL;
if ((ctx = BN_CTX_new()) == NULL)
goto err;
if (eckey->priv_key == NULL) {
priv_key = BN_new();
if (priv_key == NULL)
goto err;
} else
priv_key = eckey->priv_key;
order = EC_GROUP_get0_order(eckey->group);
if (order == NULL)
goto err;
do
if (!BN_rand_range(priv_key, order))
goto err;
while (BN_is_zero(priv_key)) ;
if (eckey->pub_key == NULL) {
pub_key = EC_POINT_new(eckey->group);
if (pub_key == NULL)
goto err;
} else
pub_key = eckey->pub_key;
if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, ctx))
goto err;
eckey->priv_key = priv_key;
eckey->pub_key = pub_key;
ok = 1;
err:
if (eckey->pub_key == NULL)
EC_POINT_free(pub_key);
if (eckey->priv_key != priv_key)
BN_free(priv_key);
BN_CTX_free(ctx);
return ok;
}
static int ssl_ec_point_offer(SSL_ECDH_CTX *ctx, CBB *out) {
assert(ctx->data == NULL);
BIGNUM *private_key = BN_new();
if (private_key == NULL) {
return 0;
}
ctx->data = private_key;
/* Set up a shared |BN_CTX| for all operations. */
BN_CTX *bn_ctx = BN_CTX_new();
if (bn_ctx == NULL) {
return 0;
}
BN_CTX_start(bn_ctx);
int ret = 0;
EC_POINT *public_key = NULL;
EC_GROUP *group = EC_GROUP_new_by_curve_name(ctx->method->nid);
if (group == NULL) {
goto err;
}
/* Generate a private key. */
const BIGNUM *order = EC_GROUP_get0_order(group);
do {
if (!BN_rand_range(private_key, order)) {
goto err;
}
} while (BN_is_zero(private_key));
/* Compute the corresponding public key and serialize it. */
public_key = EC_POINT_new(group);
if (public_key == NULL ||
!EC_POINT_mul(group, public_key, private_key, NULL, NULL, bn_ctx) ||
!EC_POINT_point2cbb(out, group, public_key, POINT_CONVERSION_UNCOMPRESSED,
bn_ctx)) {
goto err;
}
ret = 1;
err:
EC_GROUP_free(group);
EC_POINT_free(public_key);
BN_CTX_end(bn_ctx);
BN_CTX_free(bn_ctx);
return ret;
}
size_t ECDSA_size(const EC_KEY *key) {
if (key == NULL) {
return 0;
}
size_t group_order_size;
if (key->ecdsa_meth && key->ecdsa_meth->group_order_size) {
group_order_size = key->ecdsa_meth->group_order_size(key);
} else {
const EC_GROUP *group = EC_KEY_get0_group(key);
if (group == NULL) {
return 0;
}
group_order_size = BN_num_bytes(EC_GROUP_get0_order(group));
}
return ECDSA_SIG_max_len(group_order_size);
}
static int ec_GFp_mont_check_pub_key_order(const EC_GROUP *group,
const EC_POINT* pub_key,
BN_CTX *ctx) {
EC_POINT *point = EC_POINT_new(group);
int ret = 0;
if (point == NULL ||
!ec_wNAF_mul(group, point, NULL, pub_key, EC_GROUP_get0_order(group),
ctx) ||
!EC_POINT_is_at_infinity(group, point)) {
goto err;
}
ret = 1;
err:
EC_POINT_free(point);
return ret;
}
int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx)
{
int r = 0;
BIGNUM *a1, *a2, *a3, *b1, *b2, *b3;
BN_CTX *ctx_new = NULL;
/* compare the field types */
if (EC_METHOD_get_field_type(EC_GROUP_method_of(a)) !=
EC_METHOD_get_field_type(EC_GROUP_method_of(b)))
return 1;
/* compare the curve name (if present in both) */
if (EC_GROUP_get_curve_name(a) && EC_GROUP_get_curve_name(b) &&
EC_GROUP_get_curve_name(a) != EC_GROUP_get_curve_name(b))
return 1;
if (a->meth->flags & EC_FLAGS_CUSTOM_CURVE)
return 0;
if (ctx == NULL)
ctx_new = ctx = BN_CTX_new();
if (ctx == NULL)
return -1;
BN_CTX_start(ctx);
a1 = BN_CTX_get(ctx);
a2 = BN_CTX_get(ctx);
a3 = BN_CTX_get(ctx);
b1 = BN_CTX_get(ctx);
b2 = BN_CTX_get(ctx);
b3 = BN_CTX_get(ctx);
if (b3 == NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx_new);
return -1;
}
/*
* XXX This approach assumes that the external representation of curves
* over the same field type is the same.
*/
if (!a->meth->group_get_curve(a, a1, a2, a3, ctx) ||
!b->meth->group_get_curve(b, b1, b2, b3, ctx))
r = 1;
if (r || BN_cmp(a1, b1) || BN_cmp(a2, b2) || BN_cmp(a3, b3))
r = 1;
/* XXX EC_POINT_cmp() assumes that the methods are equal */
if (r || EC_POINT_cmp(a, EC_GROUP_get0_generator(a),
EC_GROUP_get0_generator(b), ctx))
r = 1;
if (!r) {
const BIGNUM *ao, *bo, *ac, *bc;
/* compare the order and cofactor */
ao = EC_GROUP_get0_order(a);
bo = EC_GROUP_get0_order(b);
ac = EC_GROUP_get0_cofactor(a);
bc = EC_GROUP_get0_cofactor(b);
if (ao == NULL || bo == NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx_new);
return -1;
}
if (BN_cmp(ao, bo) || BN_cmp(ac, bc))
r = 1;
}
BN_CTX_end(ctx);
BN_CTX_free(ctx_new);
return r;
}
ECDSA_SIG *ECDSA_do_sign_ex(const uint8_t *digest, size_t digest_len,
const BIGNUM *in_kinv, const BIGNUM *in_r,
const EC_KEY *eckey) {
int ok = 0;
BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL;
const BIGNUM *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
const BIGNUM *priv_key;
if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED);
return NULL;
}
group = EC_KEY_get0_group(eckey);
priv_key = EC_KEY_get0_private_key(eckey);
if (group == NULL || priv_key == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
ret = ECDSA_SIG_new();
if (!ret) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
return NULL;
}
s = ret->s;
if ((ctx = BN_CTX_new()) == NULL ||
(tmp = BN_new()) == NULL ||
(m = BN_new()) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
const BIGNUM *order = EC_GROUP_get0_order(group);
if (!digest_to_bn(m, digest, digest_len, order)) {
goto err;
}
for (;;) {
if (in_kinv == NULL || in_r == NULL) {
if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, digest, digest_len)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_ECDSA_LIB);
goto err;
}
ckinv = kinv;
} else {
ckinv = in_kinv;
if (BN_copy(ret->r, in_r) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
}
if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_add_quick(s, tmp, m, order)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(s)) {
// if kinv and r have been supplied by the caller
// don't to generate new kinv and r values
if (in_kinv != NULL && in_r != NULL) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NEED_NEW_SETUP_VALUES);
goto err;
}
} else {
// s != 0 => we have a valid signature
break;
}
}
ok = 1;
err:
if (!ok) {
ECDSA_SIG_free(ret);
ret = NULL;
}
BN_CTX_free(ctx);
BN_clear_free(m);
BN_clear_free(tmp);
BN_clear_free(kinv);
return ret;
}
static int ecdsa_sign_setup(const EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp, const uint8_t *digest,
size_t digest_len) {
BN_CTX *ctx = NULL;
BIGNUM *k = NULL, *kinv = NULL, *r = NULL, *tmp = NULL;
EC_POINT *tmp_point = NULL;
const EC_GROUP *group;
int ret = 0;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (ctx_in == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
return 0;
}
} else {
ctx = ctx_in;
}
k = BN_new();
kinv = BN_new(); // this value is later returned in *kinvp
r = BN_new(); // this value is later returned in *rp
tmp = BN_new();
if (k == NULL || kinv == NULL || r == NULL || tmp == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
tmp_point = EC_POINT_new(group);
if (tmp_point == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
const BIGNUM *order = EC_GROUP_get0_order(group);
// Check that the size of the group order is FIPS compliant (FIPS 186-4
// B.5.2).
if (BN_num_bits(order) < 160) {
OPENSSL_PUT_ERROR(ECDSA, EC_R_INVALID_GROUP_ORDER);
goto err;
}
do {
// If possible, we'll include the private key and message digest in the k
// generation. The |digest| argument is only empty if |ECDSA_sign_setup| is
// being used.
if (eckey->fixed_k != NULL) {
if (!BN_copy(k, eckey->fixed_k)) {
goto err;
}
} else if (digest_len > 0) {
do {
if (!BN_generate_dsa_nonce(k, order, EC_KEY_get0_private_key(eckey),
digest, digest_len, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
} while (BN_is_zero(k));
} else if (!BN_rand_range_ex(k, 1, order)) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
// Compute the inverse of k. The order is a prime, so use Fermat's Little
// Theorem. Note |ec_group_get_order_mont| may return NULL but
// |bn_mod_inverse_prime| allows this.
if (!bn_mod_inverse_prime(kinv, k, order, ctx,
ec_group_get_order_mont(group))) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
// We do not want timing information to leak the length of k,
// so we compute G*k using an equivalent scalar of fixed
// bit-length.
if (!BN_add(k, k, order)) {
goto err;
}
if (BN_num_bits(k) <= BN_num_bits(order)) {
if (!BN_add(k, k, order)) {
goto err;
}
}
// compute r the x-coordinate of generator * k
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group, tmp_point, tmp, NULL,
ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
if (!BN_nnmod(r, tmp, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
} while (BN_is_zero(r));
// clear old values if necessary
BN_clear_free(*rp);
BN_clear_free(*kinvp);
// save the pre-computed values
*rp = r;
*kinvp = kinv;
ret = 1;
err:
BN_clear_free(k);
if (!ret) {
BN_clear_free(kinv);
BN_clear_free(r);
}
if (ctx_in == NULL) {
BN_CTX_free(ctx);
}
EC_POINT_free(tmp_point);
BN_clear_free(tmp);
return ret;
}
int ECDSA_do_verify(const uint8_t *digest, size_t digest_len,
const ECDSA_SIG *sig, const EC_KEY *eckey) {
int ret = 0;
BN_CTX *ctx;
BIGNUM *u1, *u2, *m, *X;
EC_POINT *point = NULL;
const EC_GROUP *group;
const EC_POINT *pub_key;
// check input values
if ((group = EC_KEY_get0_group(eckey)) == NULL ||
(pub_key = EC_KEY_get0_public_key(eckey)) == NULL ||
sig == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_MISSING_PARAMETERS);
return 0;
}
ctx = BN_CTX_new();
if (!ctx) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
return 0;
}
BN_CTX_start(ctx);
u1 = BN_CTX_get(ctx);
u2 = BN_CTX_get(ctx);
m = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
if (u1 == NULL || u2 == NULL || m == NULL || X == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
const BIGNUM *order = EC_GROUP_get0_order(group);
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
goto err;
}
// calculate tmp1 = inv(S) mod order
int no_inverse;
if (!BN_mod_inverse_odd(u2, &no_inverse, sig->s, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (!digest_to_bn(m, digest, digest_len, order)) {
goto err;
}
// u1 = m * tmp mod order
if (!BN_mod_mul(u1, m, u2, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
// u2 = r * w mod q
if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
point = EC_POINT_new(group);
if (point == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
if (!BN_nnmod(u1, X, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
// if the signature is correct u1 is equal to sig->r
if (BN_ucmp(u1, sig->r) != 0) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
goto err;
}
ret = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
EC_POINT_free(point);
return ret;
}
static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, int ktype) {
uint8_t *buffer = NULL;
const char *ecstr;
size_t buf_len = 0, i;
int ret = 0, reason = ERR_R_BIO_LIB;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
const EC_POINT *public_key;
const BIGNUM *priv_key;
uint8_t *pub_key_bytes = NULL;
size_t pub_key_bytes_len = 0;
if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
reason = ERR_R_PASSED_NULL_PARAMETER;
goto err;
}
ctx = BN_CTX_new();
if (ctx == NULL) {
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
if (ktype > 0) {
public_key = EC_KEY_get0_public_key(x);
if (public_key != NULL) {
pub_key_bytes_len = EC_POINT_point2oct(
group, public_key, EC_KEY_get_conv_form(x), NULL, 0, ctx);
if (pub_key_bytes_len == 0) {
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
pub_key_bytes = OPENSSL_malloc(pub_key_bytes_len);
if (pub_key_bytes == NULL) {
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
pub_key_bytes_len =
EC_POINT_point2oct(group, public_key, EC_KEY_get_conv_form(x),
pub_key_bytes, pub_key_bytes_len, ctx);
if (pub_key_bytes_len == 0) {
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
buf_len = pub_key_bytes_len;
}
}
if (ktype == 2) {
priv_key = EC_KEY_get0_private_key(x);
if (priv_key && (i = (size_t)BN_num_bytes(priv_key)) > buf_len) {
buf_len = i;
}
} else {
priv_key = NULL;
}
if (ktype > 0) {
buf_len += 10;
if ((buffer = OPENSSL_malloc(buf_len)) == NULL) {
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
}
if (ktype == 2) {
ecstr = "Private-Key";
} else if (ktype == 1) {
ecstr = "Public-Key";
} else {
ecstr = "ECDSA-Parameters";
}
if (!BIO_indent(bp, off, 128)) {
goto err;
}
const BIGNUM *order = EC_GROUP_get0_order(group);
if (BIO_printf(bp, "%s: (%d bit)\n", ecstr, BN_num_bits(order)) <= 0) {
goto err;
}
if ((priv_key != NULL) &&
!ASN1_bn_print(bp, "priv:", priv_key, buffer, off)) {
goto err;
}
if (pub_key_bytes != NULL) {
BIO_hexdump(bp, pub_key_bytes, pub_key_bytes_len, off);
}
/* TODO(fork): implement */
/*
if (!ECPKParameters_print(bp, group, off))
goto err; */
ret = 1;
err:
if (!ret) {
OPENSSL_PUT_ERROR(EVP, reason);
}
OPENSSL_free(pub_key_bytes);
BN_CTX_free(ctx);
OPENSSL_free(buffer);
return ret;
}
int ossl_ecdsa_verify_sig(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey)
{
int ret = -1, i;
BN_CTX *ctx;
const BIGNUM *order;
BIGNUM *u1, *u2, *m, *X;
EC_POINT *point = NULL;
const EC_GROUP *group;
const EC_POINT *pub_key;
/* check input values */
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
(pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_MISSING_PARAMETERS);
return -1;
}
if (!EC_KEY_can_sign(eckey)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
return -1;
}
ctx = BN_CTX_new();
if (ctx == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_MALLOC_FAILURE);
return -1;
}
BN_CTX_start(ctx);
u1 = BN_CTX_get(ctx);
u2 = BN_CTX_get(ctx);
m = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
if (X == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
order = EC_GROUP_get0_order(group);
if (order == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
goto err;
}
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_BAD_SIGNATURE);
ret = 0; /* signature is invalid */
goto err;
}
/* calculate tmp1 = inv(S) mod order */
if (!BN_mod_inverse(u2, sig->s, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
/* digest -> m */
i = BN_num_bits(order);
/*
* Need to truncate digest if it is too long: first truncate whole bytes.
*/
if (8 * dgst_len > i)
dgst_len = (i + 7) / 8;
if (!BN_bin2bn(dgst, dgst_len, m)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
/* If still too long truncate remaining bits with a shift */
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
/* u1 = m * tmp mod order */
if (!BN_mod_mul(u1, m, u2, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
/* u2 = r * w mod q */
if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
if ((point = EC_POINT_new(group)) == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
goto err;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
NID_X9_62_prime_field) {
if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
goto err;
}
}
#ifndef OPENSSL_NO_EC2M
else { /* NID_X9_62_characteristic_two_field */
if (!EC_POINT_get_affine_coordinates_GF2m(group, point, X, NULL, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
goto err;
}
}
#endif
if (!BN_nnmod(u1, X, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
/* if the signature is correct u1 is equal to sig->r */
ret = (BN_ucmp(u1, sig->r) == 0);
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
EC_POINT_free(point);
return ret;
}
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
BIGNUM **kinvp, BIGNUM **rp,
const unsigned char *dgst, int dlen)
{
BN_CTX *ctx = NULL;
BIGNUM *k = NULL, *r = NULL, *X = NULL;
const BIGNUM *order;
EC_POINT *tmp_point = NULL;
const EC_GROUP *group;
int ret = 0;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (!EC_KEY_can_sign(eckey)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
return 0;
}
if (ctx_in == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
return 0;
}
} else
ctx = ctx_in;
k = BN_new(); /* this value is later returned in *kinvp */
r = BN_new(); /* this value is later returned in *rp */
X = BN_new();
if (k == NULL || r == NULL || X == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
goto err;
}
if ((tmp_point = EC_POINT_new(group)) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
order = EC_GROUP_get0_order(group);
if (order == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
do {
/* get random k */
do
if (dgst != NULL) {
if (!BN_generate_dsa_nonce
(k, order, EC_KEY_get0_private_key(eckey), dgst, dlen,
ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP,
EC_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
} else {
if (!BN_rand_range(k, order)) {
ECerr(EC_F_ECDSA_SIGN_SETUP,
EC_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
}
while (BN_is_zero(k));
/*
* We do not want timing information to leak the length of k, so we
* compute G*k using an equivalent scalar of fixed bit-length.
*/
if (!BN_add(k, k, order))
goto err;
if (BN_num_bits(k) <= BN_num_bits(order))
if (!BN_add(k, k, order))
goto err;
/* compute r the x-coordinate of generator * k */
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
NID_X9_62_prime_field) {
if (!EC_POINT_get_affine_coordinates_GFp
(group, tmp_point, X, NULL, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
}
#ifndef OPENSSL_NO_EC2M
else { /* NID_X9_62_characteristic_two_field */
if (!EC_POINT_get_affine_coordinates_GF2m(group,
tmp_point, X, NULL,
ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
}
#endif
if (!BN_nnmod(r, X, order, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
}
while (BN_is_zero(r));
/* compute the inverse of k */
if (EC_GROUP_get_mont_data(group) != NULL) {
/*
* We want inverse in constant time, therefore we utilize the fact
* order must be prime and use Fermats Little Theorem instead.
*/
if (!BN_set_word(X, 2)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_sub(X, order, X, order, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
BN_set_flags(X, BN_FLG_CONSTTIME);
if (!BN_mod_exp_mont_consttime
(k, k, X, order, ctx, EC_GROUP_get_mont_data(group))) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
} else {
if (!BN_mod_inverse(k, k, order, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
}
/* clear old values if necessary */
BN_clear_free(*rp);
BN_clear_free(*kinvp);
/* save the pre-computed values */
*rp = r;
*kinvp = k;
ret = 1;
err:
if (!ret) {
BN_clear_free(k);
BN_clear_free(r);
}
if (ctx != ctx_in)
BN_CTX_free(ctx);
EC_POINT_free(tmp_point);
BN_clear_free(X);
return (ret);
}
ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r,
EC_KEY *eckey)
{
int ok = 0, i;
BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL;
const BIGNUM *order, *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
const BIGNUM *priv_key;
group = EC_KEY_get0_group(eckey);
priv_key = EC_KEY_get0_private_key(eckey);
if (group == NULL || priv_key == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
if (!EC_KEY_can_sign(eckey)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
return NULL;
}
ret = ECDSA_SIG_new();
if (ret == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
return NULL;
}
ret->r = BN_new();
ret->s = BN_new();
if (ret->r == NULL || ret->s == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
s = ret->s;
if ((ctx = BN_CTX_new()) == NULL ||
(tmp = BN_new()) == NULL || (m = BN_new()) == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
order = EC_GROUP_get0_order(group);
if (order == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_EC_LIB);
goto err;
}
i = BN_num_bits(order);
/*
* Need to truncate digest if it is too long: first truncate whole bytes.
*/
if (8 * dgst_len > i)
dgst_len = (i + 7) / 8;
if (!BN_bin2bn(dgst, dgst_len, m)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
/* If still too long truncate remaining bits with a shift */
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
do {
if (in_kinv == NULL || in_r == NULL) {
if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, dgst, dgst_len)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_ECDSA_LIB);
goto err;
}
ckinv = kinv;
} else {
ckinv = in_kinv;
if (BN_copy(ret->r, in_r) == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
}
if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_add_quick(s, tmp, m, order)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(s)) {
/*
* if kinv and r have been supplied by the caller don't to
* generate new kinv and r values
*/
if (in_kinv != NULL && in_r != NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, EC_R_NEED_NEW_SETUP_VALUES);
goto err;
}
} else
/* s != 0 => we have a valid signature */
break;
}
while (1);
ok = 1;
err:
if (!ok) {
ECDSA_SIG_free(ret);
ret = NULL;
}
BN_CTX_free(ctx);
BN_clear_free(m);
BN_clear_free(tmp);
BN_clear_free(kinv);
return ret;
}
int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx) {
if (BN_copy(order, EC_GROUP_get0_order(group)) == NULL) {
return 0;
}
return 1;
}
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp, const uint8_t *digest,
size_t digest_len) {
BN_CTX *ctx = NULL;
BIGNUM *k = NULL, *r = NULL, *tmp = NULL;
EC_POINT *tmp_point = NULL;
const EC_GROUP *group;
int ret = 0;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (ctx_in == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
return 0;
}
} else {
ctx = ctx_in;
}
k = BN_new(); /* this value is later returned in *kinvp */
r = BN_new(); /* this value is later returned in *rp */
tmp = BN_new();
if (k == NULL || r == NULL || tmp == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
tmp_point = EC_POINT_new(group);
if (tmp_point == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
const BIGNUM *order = EC_GROUP_get0_order(group);
do {
/* If possible, we'll include the private key and message digest in the k
* generation. The |digest| argument is only empty if |ECDSA_sign_setup| is
* being used. */
if (digest_len > 0) {
do {
if (!BN_generate_dsa_nonce(k, order, EC_KEY_get0_private_key(eckey),
digest, digest_len, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
} while (BN_is_zero(k));
} else if (!BN_rand_range_ex(k, 1, order)) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
/* We do not want timing information to leak the length of k,
* so we compute G*k using an equivalent scalar of fixed
* bit-length. */
if (!BN_add(k, k, order)) {
goto err;
}
if (BN_num_bits(k) <= BN_num_bits(order)) {
if (!BN_add(k, k, order)) {
goto err;
}
}
/* compute r the x-coordinate of generator * k */
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group, tmp_point, tmp, NULL,
ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
goto err;
}
if (!BN_nnmod(r, tmp, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
} while (BN_is_zero(r));
/* Compute the inverse of k. The order is a prime, so use Fermat's Little
* Theorem. */
if (!BN_set_word(tmp, 2) ||
!BN_sub(tmp, order, tmp) ||
/* Note |ec_group_get_mont_data| may return NULL but |BN_mod_exp_mont|
* allows it to be. */
!BN_mod_exp_mont(k, k, tmp, order, ctx, ec_group_get_mont_data(group))) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
/* clear old values if necessary */
BN_clear_free(*rp);
BN_clear_free(*kinvp);
/* save the pre-computed values */
*rp = r;
*kinvp = k;
ret = 1;
err:
if (!ret) {
BN_clear_free(k);
BN_clear_free(r);
}
if (ctx_in == NULL) {
BN_CTX_free(ctx);
}
EC_POINT_free(tmp_point);
BN_clear_free(tmp);
return ret;
}
