/* 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_grpc/ec.h> #include <limits.h> #include <string.h> #include <openssl_grpc/bytestring.h> #include <openssl_grpc/bn.h> #include <openssl_grpc/err.h> #include <openssl_grpc/mem.h> #include <openssl_grpc/nid.h> #include "../fipsmodule/ec/internal.h" #include "../bytestring/internal.h" #include "../internal.h" static const unsigned kParametersTag = CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0; static const unsigned 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; BIGNUM *priv_key = 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. priv_key = BN_bin2bn(CBS_data(&private_key), CBS_len(&private_key), NULL); ret->pub_key = EC_POINT_new(group); if (priv_key == NULL || ret->pub_key == NULL || !EC_KEY_set_private_key(ret, priv_key)) { 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_scalar_base(group, &ret->pub_key->raw, &ret->priv_key->scalar)) { 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; } BN_free(priv_key); EC_GROUP_free(inner_group); return ret; err: EC_KEY_free(ret); BN_free(priv_key); 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)), EC_KEY_get0_private_key(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; } // 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, cofactor; int has_cofactor; 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) || !CBS_is_unsigned_asn1_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_optional_asn1(&curve, NULL, NULL, CBS_ASN1_BITSTRING) || CBS_len(&curve) != 0 || !CBS_get_asn1(¶ms, &base, CBS_ASN1_OCTETSTRING) || !CBS_get_asn1(¶ms, out_order, CBS_ASN1_INTEGER) || !CBS_is_unsigned_asn1_integer(out_order) || !CBS_get_optional_asn1(¶ms, &cofactor, &has_cofactor, CBS_ASN1_INTEGER) || CBS_len(¶ms) != 0) { OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR); return 0; } if (has_cofactor) { // We only support prime-order curves so the cofactor must be one. if (CBS_len(&cofactor) != 1 || CBS_data(&cofactor)[0] != 1) { OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP); return 0; } } // 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->param_len; // |curve->params| 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->params, param_len) && integers_equal(&a, curve->params + param_len, param_len) && integers_equal(&b, curve->params + param_len * 2, param_len) && integers_equal(&base_x, curve->params + param_len * 3, param_len) && integers_equal(&base_y, curve->params + param_len * 4, param_len) && integers_equal(&order, curve->params + 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; }