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- /* Written by Nils Larsch for the OpenSSL project. */
- /* ====================================================================
- * Copyright (c) 2000-2003 The OpenSSL Project. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. All advertising materials mentioning features or use of this
- * software must display the following acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
- *
- * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
- * endorse or promote products derived from this software without
- * prior written permission. For written permission, please contact
- * licensing@OpenSSL.org.
- *
- * 5. Products derived from this software may not be called "OpenSSL"
- * nor may "OpenSSL" appear in their names without prior written
- * permission of the OpenSSL Project.
- *
- * 6. Redistributions of any form whatsoever must retain the following
- * acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
- *
- * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
- * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
- * OF THE POSSIBILITY OF SUCH DAMAGE.
- * ====================================================================
- *
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com). This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com). */
-
- #include <openssl/ec.h>
-
- #include <limits.h>
- #include <string.h>
-
- #include <openssl/bytestring.h>
- #include <openssl/bn.h>
- #include <openssl/err.h>
- #include <openssl/mem.h>
- #include <openssl/nid.h>
-
- #include "../fipsmodule/ec/internal.h"
- #include "../bytestring/internal.h"
- #include "../internal.h"
-
-
- static const uint8_t kParametersTag =
- CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0;
- static const uint8_t kPublicKeyTag =
- CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 1;
-
- EC_KEY *EC_KEY_parse_private_key(CBS *cbs, const EC_GROUP *group) {
- CBS ec_private_key, private_key;
- uint64_t version;
- if (!CBS_get_asn1(cbs, &ec_private_key, CBS_ASN1_SEQUENCE) ||
- !CBS_get_asn1_uint64(&ec_private_key, &version) ||
- version != 1 ||
- !CBS_get_asn1(&ec_private_key, &private_key, CBS_ASN1_OCTETSTRING)) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- return NULL;
- }
-
- /* Parse the optional parameters field. */
- EC_GROUP *inner_group = NULL;
- EC_KEY *ret = NULL;
- if (CBS_peek_asn1_tag(&ec_private_key, kParametersTag)) {
- /* Per SEC 1, as an alternative to omitting it, one is allowed to specify
- * this field and put in a NULL to mean inheriting this value. This was
- * omitted in a previous version of this logic without problems, so leave it
- * unimplemented. */
- CBS child;
- if (!CBS_get_asn1(&ec_private_key, &child, kParametersTag)) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- goto err;
- }
- inner_group = EC_KEY_parse_parameters(&child);
- if (inner_group == NULL) {
- goto err;
- }
- if (group == NULL) {
- group = inner_group;
- } else if (EC_GROUP_cmp(group, inner_group, NULL) != 0) {
- /* If a group was supplied externally, it must match. */
- OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
- goto err;
- }
- if (CBS_len(&child) != 0) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- goto err;
- }
- }
-
- if (group == NULL) {
- OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
- goto err;
- }
-
- ret = EC_KEY_new();
- if (ret == NULL || !EC_KEY_set_group(ret, group)) {
- goto err;
- }
-
- /* Although RFC 5915 specifies the length of the key, OpenSSL historically
- * got this wrong, so accept any length. See upstream's
- * 30cd4ff294252c4b6a4b69cbef6a5b4117705d22. */
- ret->priv_key =
- BN_bin2bn(CBS_data(&private_key), CBS_len(&private_key), NULL);
- ret->pub_key = EC_POINT_new(group);
- if (ret->priv_key == NULL || ret->pub_key == NULL) {
- goto err;
- }
-
- if (BN_cmp(ret->priv_key, EC_GROUP_get0_order(group)) >= 0) {
- OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
- goto err;
- }
-
- if (CBS_peek_asn1_tag(&ec_private_key, kPublicKeyTag)) {
- CBS child, public_key;
- uint8_t padding;
- if (!CBS_get_asn1(&ec_private_key, &child, kPublicKeyTag) ||
- !CBS_get_asn1(&child, &public_key, CBS_ASN1_BITSTRING) ||
- /* As in a SubjectPublicKeyInfo, the byte-encoded public key is then
- * encoded as a BIT STRING with bits ordered as in the DER encoding. */
- !CBS_get_u8(&public_key, &padding) ||
- padding != 0 ||
- /* Explicitly check |public_key| is non-empty to save the conversion
- * form later. */
- CBS_len(&public_key) == 0 ||
- !EC_POINT_oct2point(group, ret->pub_key, CBS_data(&public_key),
- CBS_len(&public_key), NULL) ||
- CBS_len(&child) != 0) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- goto err;
- }
-
- /* Save the point conversion form.
- * TODO(davidben): Consider removing this. */
- ret->conv_form =
- (point_conversion_form_t)(CBS_data(&public_key)[0] & ~0x01);
- } else {
- /* Compute the public key instead. */
- if (!EC_POINT_mul(group, ret->pub_key, ret->priv_key, NULL, NULL, NULL)) {
- goto err;
- }
- /* Remember the original private-key-only encoding.
- * TODO(davidben): Consider removing this. */
- ret->enc_flag |= EC_PKEY_NO_PUBKEY;
- }
-
- if (CBS_len(&ec_private_key) != 0) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- goto err;
- }
-
- /* Ensure the resulting key is valid. */
- if (!EC_KEY_check_key(ret)) {
- goto err;
- }
-
- EC_GROUP_free(inner_group);
- return ret;
-
- err:
- EC_KEY_free(ret);
- EC_GROUP_free(inner_group);
- return NULL;
- }
-
- int EC_KEY_marshal_private_key(CBB *cbb, const EC_KEY *key,
- unsigned enc_flags) {
- if (key == NULL || key->group == NULL || key->priv_key == NULL) {
- OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
- return 0;
- }
-
- CBB ec_private_key, private_key;
- if (!CBB_add_asn1(cbb, &ec_private_key, CBS_ASN1_SEQUENCE) ||
- !CBB_add_asn1_uint64(&ec_private_key, 1 /* version */) ||
- !CBB_add_asn1(&ec_private_key, &private_key, CBS_ASN1_OCTETSTRING) ||
- !BN_bn2cbb_padded(&private_key,
- BN_num_bytes(EC_GROUP_get0_order(key->group)),
- key->priv_key)) {
- OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
- return 0;
- }
-
- if (!(enc_flags & EC_PKEY_NO_PARAMETERS)) {
- CBB child;
- if (!CBB_add_asn1(&ec_private_key, &child, kParametersTag) ||
- !EC_KEY_marshal_curve_name(&child, key->group) ||
- !CBB_flush(&ec_private_key)) {
- OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
- return 0;
- }
- }
-
- /* TODO(fork): replace this flexibility with sensible default? */
- if (!(enc_flags & EC_PKEY_NO_PUBKEY) && key->pub_key != NULL) {
- CBB child, public_key;
- if (!CBB_add_asn1(&ec_private_key, &child, kPublicKeyTag) ||
- !CBB_add_asn1(&child, &public_key, CBS_ASN1_BITSTRING) ||
- /* As in a SubjectPublicKeyInfo, the byte-encoded public key is then
- * encoded as a BIT STRING with bits ordered as in the DER encoding. */
- !CBB_add_u8(&public_key, 0 /* padding */) ||
- !EC_POINT_point2cbb(&public_key, key->group, key->pub_key,
- key->conv_form, NULL) ||
- !CBB_flush(&ec_private_key)) {
- OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
- return 0;
- }
- }
-
- if (!CBB_flush(cbb)) {
- OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
- return 0;
- }
-
- return 1;
- }
-
- /* is_unsigned_integer returns one if |cbs| is a valid unsigned DER INTEGER and
- * zero otherwise. */
- static int is_unsigned_integer(const CBS *cbs) {
- if (CBS_len(cbs) == 0) {
- return 0;
- }
- uint8_t byte = CBS_data(cbs)[0];
- if ((byte & 0x80) ||
- (byte == 0 && CBS_len(cbs) > 1 && (CBS_data(cbs)[1] & 0x80) == 0)) {
- /* Negative or not minimally-encoded. */
- return 0;
- }
- return 1;
- }
-
- /* kPrimeFieldOID is the encoding of 1.2.840.10045.1.1. */
- static const uint8_t kPrimeField[] = {0x2a, 0x86, 0x48, 0xce, 0x3d, 0x01, 0x01};
-
- static int parse_explicit_prime_curve(CBS *in, CBS *out_prime, CBS *out_a,
- CBS *out_b, CBS *out_base_x,
- CBS *out_base_y, CBS *out_order) {
- /* See RFC 3279, section 2.3.5. Note that RFC 3279 calls this structure an
- * ECParameters while RFC 5480 calls it a SpecifiedECDomain. */
- CBS params, field_id, field_type, curve, base;
- uint64_t version;
- if (!CBS_get_asn1(in, ¶ms, CBS_ASN1_SEQUENCE) ||
- !CBS_get_asn1_uint64(¶ms, &version) ||
- version != 1 ||
- !CBS_get_asn1(¶ms, &field_id, CBS_ASN1_SEQUENCE) ||
- !CBS_get_asn1(&field_id, &field_type, CBS_ASN1_OBJECT) ||
- CBS_len(&field_type) != sizeof(kPrimeField) ||
- OPENSSL_memcmp(CBS_data(&field_type), kPrimeField, sizeof(kPrimeField)) != 0 ||
- !CBS_get_asn1(&field_id, out_prime, CBS_ASN1_INTEGER) ||
- !is_unsigned_integer(out_prime) ||
- CBS_len(&field_id) != 0 ||
- !CBS_get_asn1(¶ms, &curve, CBS_ASN1_SEQUENCE) ||
- !CBS_get_asn1(&curve, out_a, CBS_ASN1_OCTETSTRING) ||
- !CBS_get_asn1(&curve, out_b, CBS_ASN1_OCTETSTRING) ||
- /* |curve| has an optional BIT STRING seed which we ignore. */
- !CBS_get_asn1(¶ms, &base, CBS_ASN1_OCTETSTRING) ||
- !CBS_get_asn1(¶ms, out_order, CBS_ASN1_INTEGER) ||
- !is_unsigned_integer(out_order)) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- return 0;
- }
-
- /* |params| has an optional cofactor which we ignore. With the optional seed
- * in |curve|, a group already has arbitrarily many encodings. Parse enough to
- * uniquely determine the curve. */
-
- /* Require that the base point use uncompressed form. */
- uint8_t form;
- if (!CBS_get_u8(&base, &form) || form != POINT_CONVERSION_UNCOMPRESSED) {
- OPENSSL_PUT_ERROR(EC, EC_R_INVALID_FORM);
- return 0;
- }
-
- if (CBS_len(&base) % 2 != 0) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- return 0;
- }
- size_t field_len = CBS_len(&base) / 2;
- CBS_init(out_base_x, CBS_data(&base), field_len);
- CBS_init(out_base_y, CBS_data(&base) + field_len, field_len);
-
- return 1;
- }
-
- /* integers_equal returns one if |a| and |b| are equal, up to leading zeros, and
- * zero otherwise. */
- static int integers_equal(const CBS *a, const uint8_t *b, size_t b_len) {
- /* Remove leading zeros from |a| and |b|. */
- CBS a_copy = *a;
- while (CBS_len(&a_copy) > 0 && CBS_data(&a_copy)[0] == 0) {
- CBS_skip(&a_copy, 1);
- }
- while (b_len > 0 && b[0] == 0) {
- b++;
- b_len--;
- }
- return CBS_mem_equal(&a_copy, b, b_len);
- }
-
- EC_GROUP *EC_KEY_parse_curve_name(CBS *cbs) {
- CBS named_curve;
- if (!CBS_get_asn1(cbs, &named_curve, CBS_ASN1_OBJECT)) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- return NULL;
- }
-
- /* Look for a matching curve. */
- const struct built_in_curves *const curves = OPENSSL_built_in_curves();
- for (size_t i = 0; i < OPENSSL_NUM_BUILT_IN_CURVES; i++) {
- const struct built_in_curve *curve = &curves->curves[i];
- if (CBS_len(&named_curve) == curve->oid_len &&
- OPENSSL_memcmp(CBS_data(&named_curve), curve->oid, curve->oid_len) ==
- 0) {
- return EC_GROUP_new_by_curve_name(curve->nid);
- }
- }
-
- OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
- return NULL;
- }
-
- int EC_KEY_marshal_curve_name(CBB *cbb, const EC_GROUP *group) {
- int nid = EC_GROUP_get_curve_name(group);
- if (nid == NID_undef) {
- OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
- return 0;
- }
-
- const struct built_in_curves *const curves = OPENSSL_built_in_curves();
- for (size_t i = 0; i < OPENSSL_NUM_BUILT_IN_CURVES; i++) {
- const struct built_in_curve *curve = &curves->curves[i];
- if (curve->nid == nid) {
- CBB child;
- return CBB_add_asn1(cbb, &child, CBS_ASN1_OBJECT) &&
- CBB_add_bytes(&child, curve->oid, curve->oid_len) &&
- CBB_flush(cbb);
- }
- }
-
- OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
- return 0;
- }
-
- EC_GROUP *EC_KEY_parse_parameters(CBS *cbs) {
- if (!CBS_peek_asn1_tag(cbs, CBS_ASN1_SEQUENCE)) {
- return EC_KEY_parse_curve_name(cbs);
- }
-
- /* OpenSSL sometimes produces ECPrivateKeys with explicitly-encoded versions
- * of named curves.
- *
- * TODO(davidben): Remove support for this. */
- CBS prime, a, b, base_x, base_y, order;
- if (!parse_explicit_prime_curve(cbs, &prime, &a, &b, &base_x, &base_y,
- &order)) {
- return NULL;
- }
-
- /* Look for a matching prime curve. */
- const struct built_in_curves *const curves = OPENSSL_built_in_curves();
- for (size_t i = 0; i < OPENSSL_NUM_BUILT_IN_CURVES; i++) {
- const struct built_in_curve *curve = &curves->curves[i];
- const unsigned param_len = curve->data->param_len;
- /* |curve->data->data| is ordered p, a, b, x, y, order, each component
- * zero-padded up to the field length. Although SEC 1 states that the
- * Field-Element-to-Octet-String conversion also pads, OpenSSL mis-encodes
- * |a| and |b|, so this comparison must allow omitting leading zeros. (This
- * is relevant for P-521 whose |b| has a leading 0.) */
- if (integers_equal(&prime, curve->data->data, param_len) &&
- integers_equal(&a, curve->data->data + param_len, param_len) &&
- integers_equal(&b, curve->data->data + param_len * 2, param_len) &&
- integers_equal(&base_x, curve->data->data + param_len * 3, param_len) &&
- integers_equal(&base_y, curve->data->data + param_len * 4, param_len) &&
- integers_equal(&order, curve->data->data + param_len * 5, param_len)) {
- return EC_GROUP_new_by_curve_name(curve->nid);
- }
- }
-
- OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
- return NULL;
- }
-
- int EC_POINT_point2cbb(CBB *out, const EC_GROUP *group, const EC_POINT *point,
- point_conversion_form_t form, BN_CTX *ctx) {
- size_t len = EC_POINT_point2oct(group, point, form, NULL, 0, ctx);
- if (len == 0) {
- return 0;
- }
- uint8_t *p;
- return CBB_add_space(out, &p, len) &&
- EC_POINT_point2oct(group, point, form, p, len, ctx) == len;
- }
-
- EC_KEY *d2i_ECPrivateKey(EC_KEY **out, const uint8_t **inp, long len) {
- /* This function treats its |out| parameter differently from other |d2i|
- * functions. If supplied, take the group from |*out|. */
- const EC_GROUP *group = NULL;
- if (out != NULL && *out != NULL) {
- group = EC_KEY_get0_group(*out);
- }
-
- if (len < 0) {
- OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
- return NULL;
- }
- CBS cbs;
- CBS_init(&cbs, *inp, (size_t)len);
- EC_KEY *ret = EC_KEY_parse_private_key(&cbs, group);
- if (ret == NULL) {
- return NULL;
- }
- if (out != NULL) {
- EC_KEY_free(*out);
- *out = ret;
- }
- *inp = CBS_data(&cbs);
- return ret;
- }
-
- int i2d_ECPrivateKey(const EC_KEY *key, uint8_t **outp) {
- CBB cbb;
- if (!CBB_init(&cbb, 0) ||
- !EC_KEY_marshal_private_key(&cbb, key, EC_KEY_get_enc_flags(key))) {
- CBB_cleanup(&cbb);
- return -1;
- }
- return CBB_finish_i2d(&cbb, outp);
- }
-
- EC_KEY *d2i_ECParameters(EC_KEY **out_key, const uint8_t **inp, long len) {
- if (len < 0) {
- return NULL;
- }
-
- CBS cbs;
- CBS_init(&cbs, *inp, (size_t)len);
- EC_GROUP *group = EC_KEY_parse_parameters(&cbs);
- if (group == NULL) {
- return NULL;
- }
-
- EC_KEY *ret = EC_KEY_new();
- if (ret == NULL || !EC_KEY_set_group(ret, group)) {
- EC_GROUP_free(group);
- EC_KEY_free(ret);
- return NULL;
- }
- EC_GROUP_free(group);
-
- if (out_key != NULL) {
- EC_KEY_free(*out_key);
- *out_key = ret;
- }
- *inp = CBS_data(&cbs);
- return ret;
- }
-
- int i2d_ECParameters(const EC_KEY *key, uint8_t **outp) {
- if (key == NULL || key->group == NULL) {
- OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
- return -1;
- }
-
- CBB cbb;
- if (!CBB_init(&cbb, 0) ||
- !EC_KEY_marshal_curve_name(&cbb, key->group)) {
- CBB_cleanup(&cbb);
- return -1;
- }
- return CBB_finish_i2d(&cbb, outp);
- }
-
- EC_KEY *o2i_ECPublicKey(EC_KEY **keyp, const uint8_t **inp, long len) {
- EC_KEY *ret = NULL;
-
- if (keyp == NULL || *keyp == NULL || (*keyp)->group == NULL) {
- OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
- return NULL;
- }
- ret = *keyp;
- if (ret->pub_key == NULL &&
- (ret->pub_key = EC_POINT_new(ret->group)) == NULL) {
- OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
- return NULL;
- }
- if (!EC_POINT_oct2point(ret->group, ret->pub_key, *inp, len, NULL)) {
- OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
- return NULL;
- }
- /* save the point conversion form */
- ret->conv_form = (point_conversion_form_t)(*inp[0] & ~0x01);
- *inp += len;
- return ret;
- }
-
- int i2o_ECPublicKey(const EC_KEY *key, uint8_t **outp) {
- size_t buf_len = 0;
- int new_buffer = 0;
-
- if (key == NULL) {
- OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
- return 0;
- }
-
- buf_len = EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, NULL,
- 0, NULL);
-
- if (outp == NULL || buf_len == 0) {
- /* out == NULL => just return the length of the octet string */
- return buf_len;
- }
-
- if (*outp == NULL) {
- *outp = OPENSSL_malloc(buf_len);
- if (*outp == NULL) {
- OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
- return 0;
- }
- new_buffer = 1;
- }
- if (!EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, *outp,
- buf_len, NULL)) {
- OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
- if (new_buffer) {
- OPENSSL_free(*outp);
- *outp = NULL;
- }
- return 0;
- }
-
- if (!new_buffer) {
- *outp += buf_len;
- }
- return buf_len;
- }
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