/* * Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ /* * ECDH and ECDSA low level APIs are deprecated for public use, but still ok * for internal use. */ #include "internal/deprecated.h" #include #include "internal/cryptlib.h" #include #include #include #include #include "crypto/asn1.h" #include "crypto/evp.h" #include "crypto/x509.h" #include #include #include "ec_local.h" static int eckey_param2type(int *pptype, void **ppval, const EC_KEY *ec_key) { const EC_GROUP *group; int nid; if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) { ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS); return 0; } if (EC_GROUP_get_asn1_flag(group) && (nid = EC_GROUP_get_curve_name(group))) /* we have a 'named curve' => just set the OID */ { ASN1_OBJECT *asn1obj = OBJ_nid2obj(nid); if (asn1obj == NULL || OBJ_length(asn1obj) == 0) { ERR_raise(ERR_LIB_EC, EC_R_MISSING_OID); return 0; } *ppval = asn1obj; *pptype = V_ASN1_OBJECT; } else { /* explicit parameters */ ASN1_STRING *pstr = NULL; pstr = ASN1_STRING_new(); if (pstr == NULL) return 0; pstr->length = i2d_ECParameters(ec_key, &pstr->data); if (pstr->length <= 0) { ASN1_STRING_free(pstr); ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); return 0; } *ppval = pstr; *pptype = V_ASN1_SEQUENCE; } return 1; } static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey) { const EC_KEY *ec_key = pkey->pkey.ec; void *pval = NULL; int ptype; unsigned char *penc = NULL, *p; int penclen; if (!eckey_param2type(&ptype, &pval, ec_key)) { ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); return 0; } penclen = i2o_ECPublicKey(ec_key, NULL); if (penclen <= 0) goto err; penc = OPENSSL_malloc(penclen); if (penc == NULL) goto err; p = penc; penclen = i2o_ECPublicKey(ec_key, &p); if (penclen <= 0) goto err; if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC), ptype, pval, penc, penclen)) return 1; err: if (ptype == V_ASN1_SEQUENCE) ASN1_STRING_free(pval); OPENSSL_free(penc); return 0; } static int eckey_pub_decode(EVP_PKEY *pkey, const X509_PUBKEY *pubkey) { const unsigned char *p = NULL; int pklen; EC_KEY *eckey = NULL; X509_ALGOR *palg; OSSL_LIB_CTX *libctx = NULL; const char *propq = NULL; if (!ossl_x509_PUBKEY_get0_libctx(&libctx, &propq, pubkey) || !X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey)) return 0; eckey = ossl_ec_key_param_from_x509_algor(palg, libctx, propq); if (!eckey) return 0; /* We have parameters now set public key */ if (!o2i_ECPublicKey(&eckey, &p, pklen)) { ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR); goto ecerr; } EVP_PKEY_assign_EC_KEY(pkey, eckey); return 1; ecerr: EC_KEY_free(eckey); return 0; } static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b) { int r; const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec); const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec), *pb = EC_KEY_get0_public_key(b->pkey.ec); if (group == NULL || pa == NULL || pb == NULL) return -2; r = EC_POINT_cmp(group, pa, pb, NULL); if (r == 0) return 1; if (r == 1) return 0; return -2; } static int eckey_priv_decode_ex(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8, OSSL_LIB_CTX *libctx, const char *propq) { int ret = 0; EC_KEY *eckey = ossl_ec_key_from_pkcs8(p8, libctx, propq); if (eckey != NULL) { ret = 1; EVP_PKEY_assign_EC_KEY(pkey, eckey); } return ret; } static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey) { EC_KEY ec_key = *(pkey->pkey.ec); unsigned char *ep = NULL; int eplen, ptype; void *pval; unsigned int old_flags; if (!eckey_param2type(&ptype, &pval, &ec_key)) { ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR); return 0; } /* set the private key */ /* * do not include the parameters in the SEC1 private key see PKCS#11 * 12.11 */ old_flags = EC_KEY_get_enc_flags(&ec_key); EC_KEY_set_enc_flags(&ec_key, old_flags | EC_PKEY_NO_PARAMETERS); eplen = i2d_ECPrivateKey(&ec_key, &ep); if (eplen <= 0) { ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); goto err; } if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0, ptype, pval, ep, eplen)) { ERR_raise(ERR_LIB_EC, ERR_R_ASN1_LIB); OPENSSL_clear_free(ep, eplen); goto err; } return 1; err: if (ptype == V_ASN1_SEQUENCE) ASN1_STRING_free(pval); return 0; } static int int_ec_size(const EVP_PKEY *pkey) { return ECDSA_size(pkey->pkey.ec); } static int ec_bits(const EVP_PKEY *pkey) { return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec)); } static int ec_security_bits(const EVP_PKEY *pkey) { int ecbits = ec_bits(pkey); if (ecbits >= 512) return 256; if (ecbits >= 384) return 192; if (ecbits >= 256) return 128; if (ecbits >= 224) return 112; if (ecbits >= 160) return 80; return ecbits / 2; } static int ec_missing_parameters(const EVP_PKEY *pkey) { if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL) return 1; return 0; } static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from) { EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec)); if (group == NULL) return 0; if (to->pkey.ec == NULL) { to->pkey.ec = EC_KEY_new(); if (to->pkey.ec == NULL) goto err; } if (EC_KEY_set_group(to->pkey.ec, group) == 0) goto err; EC_GROUP_free(group); return 1; err: EC_GROUP_free(group); return 0; } static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b) { const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec), *group_b = EC_KEY_get0_group(b->pkey.ec); if (group_a == NULL || group_b == NULL) return -2; if (EC_GROUP_cmp(group_a, group_b, NULL)) return 0; else return 1; } static void int_ec_free(EVP_PKEY *pkey) { EC_KEY_free(pkey->pkey.ec); } typedef enum { EC_KEY_PRINT_PRIVATE, EC_KEY_PRINT_PUBLIC, EC_KEY_PRINT_PARAM } ec_print_t; static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype) { const char *ecstr; unsigned char *priv = NULL, *pub = NULL; size_t privlen = 0, publen = 0; int ret = 0; const EC_GROUP *group; if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } if (ktype != EC_KEY_PRINT_PARAM && EC_KEY_get0_public_key(x) != NULL) { publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL); if (publen == 0) goto err; } if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) { privlen = EC_KEY_priv2buf(x, &priv); if (privlen == 0) goto err; } if (ktype == EC_KEY_PRINT_PRIVATE) ecstr = "Private-Key"; else if (ktype == EC_KEY_PRINT_PUBLIC) ecstr = "Public-Key"; else ecstr = "ECDSA-Parameters"; if (!BIO_indent(bp, off, 128)) goto err; if (BIO_printf(bp, "%s: (%d bit)\n", ecstr, EC_GROUP_order_bits(group)) <= 0) goto err; if (privlen != 0) { if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0) goto err; if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0) goto err; } if (publen != 0) { if (BIO_printf(bp, "%*spub:\n", off, "") <= 0) goto err; if (ASN1_buf_print(bp, pub, publen, off + 4) == 0) goto err; } if (!ECPKParameters_print(bp, group, off)) goto err; ret = 1; err: if (!ret) ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); OPENSSL_clear_free(priv, privlen); OPENSSL_free(pub); return ret; } static int eckey_param_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen) { EC_KEY *eckey; if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) return 0; EVP_PKEY_assign_EC_KEY(pkey, eckey); return 1; } static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder) { return i2d_ECParameters(pkey->pkey.ec, pder); } static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx) { return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM); } static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx) { return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC); } static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx) { return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE); } static int old_ec_priv_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen) { EC_KEY *ec; if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) return 0; EVP_PKEY_assign_EC_KEY(pkey, ec); return 1; } static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder) { return i2d_ECPrivateKey(pkey->pkey.ec, pder); } static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2) { switch (op) { case ASN1_PKEY_CTRL_DEFAULT_MD_NID: if (EVP_PKEY_get_id(pkey) == EVP_PKEY_SM2) { /* For SM2, the only valid digest-alg is SM3 */ *(int *)arg2 = NID_sm3; return 2; /* Make it mandatory */ } *(int *)arg2 = NID_sha256; return 1; case ASN1_PKEY_CTRL_SET1_TLS_ENCPT: /* We should only be here if we have a legacy key */ if (!ossl_assert(evp_pkey_is_legacy(pkey))) return 0; return EC_KEY_oct2key(evp_pkey_get0_EC_KEY_int(pkey), arg2, arg1, NULL); case ASN1_PKEY_CTRL_GET1_TLS_ENCPT: return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey), POINT_CONVERSION_UNCOMPRESSED, arg2, NULL); default: return -2; } } static int ec_pkey_check(const EVP_PKEY *pkey) { EC_KEY *eckey = pkey->pkey.ec; /* stay consistent to what EVP_PKEY_check demands */ if (eckey->priv_key == NULL) { ERR_raise(ERR_LIB_EC, EC_R_MISSING_PRIVATE_KEY); return 0; } return EC_KEY_check_key(eckey); } static int ec_pkey_public_check(const EVP_PKEY *pkey) { EC_KEY *eckey = pkey->pkey.ec; /* * Note: it unnecessary to check eckey->pub_key here since * it will be checked in EC_KEY_check_key(). In fact, the * EC_KEY_check_key() mainly checks the public key, and checks * the private key optionally (only if there is one). So if * someone passes a whole EC key (public + private), this * will also work... */ return EC_KEY_check_key(eckey); } static int ec_pkey_param_check(const EVP_PKEY *pkey) { EC_KEY *eckey = pkey->pkey.ec; /* stay consistent to what EVP_PKEY_check demands */ if (eckey->group == NULL) { ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS); return 0; } return EC_GROUP_check(eckey->group, NULL); } static size_t ec_pkey_dirty_cnt(const EVP_PKEY *pkey) { return pkey->pkey.ec->dirty_cnt; } static int ec_pkey_export_to(const EVP_PKEY *from, void *to_keydata, OSSL_FUNC_keymgmt_import_fn *importer, OSSL_LIB_CTX *libctx, const char *propq) { const EC_KEY *eckey = NULL; const EC_GROUP *ecg = NULL; unsigned char *pub_key_buf = NULL, *gen_buf = NULL; size_t pub_key_buflen; OSSL_PARAM_BLD *tmpl; OSSL_PARAM *params = NULL; const BIGNUM *priv_key = NULL; const EC_POINT *pub_point = NULL; int selection = 0; int rv = 0; BN_CTX *bnctx = NULL; if (from == NULL || (eckey = from->pkey.ec) == NULL || (ecg = EC_KEY_get0_group(eckey)) == NULL) return 0; tmpl = OSSL_PARAM_BLD_new(); if (tmpl == NULL) return 0; /* * EC_POINT_point2buf() can generate random numbers in some * implementations so we need to ensure we use the correct libctx. */ bnctx = BN_CTX_new_ex(libctx); if (bnctx == NULL) goto err; BN_CTX_start(bnctx); /* export the domain parameters */ if (!ossl_ec_group_todata(ecg, tmpl, NULL, libctx, propq, bnctx, &gen_buf)) goto err; selection |= OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS; priv_key = EC_KEY_get0_private_key(eckey); pub_point = EC_KEY_get0_public_key(eckey); if (pub_point != NULL) { /* convert pub_point to a octet string according to the SECG standard */ point_conversion_form_t format = EC_KEY_get_conv_form(eckey); if ((pub_key_buflen = EC_POINT_point2buf(ecg, pub_point, format, &pub_key_buf, bnctx)) == 0 || !OSSL_PARAM_BLD_push_octet_string(tmpl, OSSL_PKEY_PARAM_PUB_KEY, pub_key_buf, pub_key_buflen)) goto err; selection |= OSSL_KEYMGMT_SELECT_PUBLIC_KEY; } if (priv_key != NULL) { size_t sz; int ecbits; int ecdh_cofactor_mode; /* * Key import/export should never leak the bit length of the secret * scalar in the key. * * For this reason, on export we use padded BIGNUMs with fixed length. * * When importing we also should make sure that, even if short lived, * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as * soon as possible, so that any processing of this BIGNUM might opt for * constant time implementations in the backend. * * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have * to preallocate the BIGNUM internal buffer to a fixed public size big * enough that operations performed during the processing never trigger * a realloc which would leak the size of the scalar through memory * accesses. * * Fixed Length * ------------ * * The order of the large prime subgroup of the curve is our choice for * a fixed public size, as that is generally the upper bound for * generating a private key in EC cryptosystems and should fit all valid * secret scalars. * * For padding on export we just use the bit length of the order * converted to bytes (rounding up). * * For preallocating the BIGNUM storage we look at the number of "words" * required for the internal representation of the order, and we * preallocate 2 extra "words" in case any of the subsequent processing * might temporarily overflow the order length. */ ecbits = EC_GROUP_order_bits(ecg); if (ecbits <= 0) goto err; sz = (ecbits + 7) / 8; if (!OSSL_PARAM_BLD_push_BN_pad(tmpl, OSSL_PKEY_PARAM_PRIV_KEY, priv_key, sz)) goto err; selection |= OSSL_KEYMGMT_SELECT_PRIVATE_KEY; /* * The ECDH Cofactor Mode is defined only if the EC_KEY actually * contains a private key, so we check for the flag and export it only * in this case. */ ecdh_cofactor_mode = (EC_KEY_get_flags(eckey) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0; /* Export the ECDH_COFACTOR_MODE parameter */ if (!OSSL_PARAM_BLD_push_int(tmpl, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, ecdh_cofactor_mode)) goto err; selection |= OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS; } params = OSSL_PARAM_BLD_to_param(tmpl); /* We export, the provider imports */ rv = importer(to_keydata, selection, params); err: OSSL_PARAM_BLD_free(tmpl); OSSL_PARAM_free(params); OPENSSL_free(pub_key_buf); OPENSSL_free(gen_buf); BN_CTX_end(bnctx); BN_CTX_free(bnctx); return rv; } static int ec_pkey_import_from(const OSSL_PARAM params[], void *vpctx) { EVP_PKEY_CTX *pctx = vpctx; EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(pctx); EC_KEY *ec = EC_KEY_new_ex(pctx->libctx, pctx->propquery); if (ec == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); return 0; } if (!ossl_ec_group_fromdata(ec, params) || !ossl_ec_key_otherparams_fromdata(ec, params) || !ossl_ec_key_fromdata(ec, params, 1) || !EVP_PKEY_assign_EC_KEY(pkey, ec)) { EC_KEY_free(ec); return 0; } return 1; } static int ec_pkey_copy(EVP_PKEY *to, EVP_PKEY *from) { EC_KEY *eckey = from->pkey.ec; EC_KEY *dupkey = NULL; int ret; if (eckey != NULL) { dupkey = EC_KEY_dup(eckey); if (dupkey == NULL) return 0; } else { /* necessary to properly copy empty SM2 keys */ return EVP_PKEY_set_type(to, from->type); } ret = EVP_PKEY_assign_EC_KEY(to, dupkey); if (!ret) EC_KEY_free(dupkey); return ret; } const EVP_PKEY_ASN1_METHOD ossl_eckey_asn1_meth = { EVP_PKEY_EC, EVP_PKEY_EC, 0, "EC", "OpenSSL EC algorithm", eckey_pub_decode, eckey_pub_encode, eckey_pub_cmp, eckey_pub_print, NULL, eckey_priv_encode, eckey_priv_print, int_ec_size, ec_bits, ec_security_bits, eckey_param_decode, eckey_param_encode, ec_missing_parameters, ec_copy_parameters, ec_cmp_parameters, eckey_param_print, 0, int_ec_free, ec_pkey_ctrl, old_ec_priv_decode, old_ec_priv_encode, 0, 0, 0, ec_pkey_check, ec_pkey_public_check, ec_pkey_param_check, 0, /* set_priv_key */ 0, /* set_pub_key */ 0, /* get_priv_key */ 0, /* get_pub_key */ ec_pkey_dirty_cnt, ec_pkey_export_to, ec_pkey_import_from, ec_pkey_copy, eckey_priv_decode_ex }; #if !defined(OPENSSL_NO_SM2) const EVP_PKEY_ASN1_METHOD ossl_sm2_asn1_meth = { EVP_PKEY_SM2, EVP_PKEY_EC, ASN1_PKEY_ALIAS }; #endif int EC_KEY_print(BIO *bp, const EC_KEY *x, int off) { int private = EC_KEY_get0_private_key(x) != NULL; return do_EC_KEY_print(bp, x, off, private ? EC_KEY_PRINT_PRIVATE : EC_KEY_PRINT_PUBLIC); } int ECParameters_print(BIO *bp, const EC_KEY *x) { return do_EC_KEY_print(bp, x, 4, EC_KEY_PRINT_PARAM); }