/* * Copyright 2002-2024 The OpenSSL Project Authors. All Rights Reserved. * Copyright (c) 2002, Oracle and/or its affiliates. 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 */ /* * EC_KEY low level APIs are deprecated for public use, but still ok for * internal use. */ #include "internal/deprecated.h" #include "internal/cryptlib.h" #include #include "ec_local.h" #include "internal/refcount.h" #include #ifndef FIPS_MODULE # include #endif #include #include "prov/providercommon.h" #include "prov/ecx.h" #include "crypto/bn.h" static int ecdsa_keygen_pairwise_test(EC_KEY *eckey, OSSL_CALLBACK *cb, void *cbarg); #ifndef FIPS_MODULE EC_KEY *EC_KEY_new(void) { return ossl_ec_key_new_method_int(NULL, NULL, NULL); } #endif EC_KEY *EC_KEY_new_ex(OSSL_LIB_CTX *ctx, const char *propq) { return ossl_ec_key_new_method_int(ctx, propq, NULL); } EC_KEY *EC_KEY_new_by_curve_name_ex(OSSL_LIB_CTX *ctx, const char *propq, int nid) { EC_KEY *ret = EC_KEY_new_ex(ctx, propq); if (ret == NULL) return NULL; ret->group = EC_GROUP_new_by_curve_name_ex(ctx, propq, nid); if (ret->group == NULL) { EC_KEY_free(ret); return NULL; } if (ret->meth->set_group != NULL && ret->meth->set_group(ret, ret->group) == 0) { EC_KEY_free(ret); return NULL; } return ret; } #ifndef FIPS_MODULE EC_KEY *EC_KEY_new_by_curve_name(int nid) { return EC_KEY_new_by_curve_name_ex(NULL, NULL, nid); } #endif void EC_KEY_free(EC_KEY *r) { int i; if (r == NULL) return; CRYPTO_DOWN_REF(&r->references, &i); REF_PRINT_COUNT("EC_KEY", r); if (i > 0) return; REF_ASSERT_ISNT(i < 0); if (r->meth != NULL && r->meth->finish != NULL) r->meth->finish(r); #if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE) ENGINE_finish(r->engine); #endif if (r->group && r->group->meth->keyfinish) r->group->meth->keyfinish(r); #ifndef FIPS_MODULE CRYPTO_free_ex_data(CRYPTO_EX_INDEX_EC_KEY, r, &r->ex_data); #endif CRYPTO_FREE_REF(&r->references); EC_GROUP_free(r->group); EC_POINT_free(r->pub_key); BN_clear_free(r->priv_key); OPENSSL_free(r->propq); OPENSSL_clear_free((void *)r, sizeof(EC_KEY)); } EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src) { if (dest == NULL || src == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return NULL; } if (src->meth != dest->meth) { if (dest->meth->finish != NULL) dest->meth->finish(dest); if (dest->group && dest->group->meth->keyfinish) dest->group->meth->keyfinish(dest); #if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE) if (ENGINE_finish(dest->engine) == 0) return 0; dest->engine = NULL; #endif } dest->libctx = src->libctx; /* copy the parameters */ if (src->group != NULL) { /* clear the old group */ EC_GROUP_free(dest->group); dest->group = ossl_ec_group_new_ex(src->libctx, src->propq, src->group->meth); if (dest->group == NULL) return NULL; if (!EC_GROUP_copy(dest->group, src->group)) return NULL; /* copy the public key */ if (src->pub_key != NULL) { EC_POINT_free(dest->pub_key); dest->pub_key = EC_POINT_new(src->group); if (dest->pub_key == NULL) return NULL; if (!EC_POINT_copy(dest->pub_key, src->pub_key)) return NULL; } /* copy the private key */ if (src->priv_key != NULL) { if (dest->priv_key == NULL) { dest->priv_key = BN_new(); if (dest->priv_key == NULL) return NULL; } if (!BN_copy(dest->priv_key, src->priv_key)) return NULL; if (src->group->meth->keycopy && src->group->meth->keycopy(dest, src) == 0) return NULL; } } /* copy the rest */ dest->enc_flag = src->enc_flag; dest->conv_form = src->conv_form; dest->version = src->version; dest->flags = src->flags; #ifndef FIPS_MODULE if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_EC_KEY, &dest->ex_data, &src->ex_data)) return NULL; #endif if (src->meth != dest->meth) { #if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE) if (src->engine != NULL && ENGINE_init(src->engine) == 0) return NULL; dest->engine = src->engine; #endif dest->meth = src->meth; } if (src->meth->copy != NULL && src->meth->copy(dest, src) == 0) return NULL; dest->dirty_cnt++; return dest; } EC_KEY *EC_KEY_dup(const EC_KEY *ec_key) { return ossl_ec_key_dup(ec_key, OSSL_KEYMGMT_SELECT_ALL); } int EC_KEY_up_ref(EC_KEY *r) { int i; if (CRYPTO_UP_REF(&r->references, &i) <= 0) return 0; REF_PRINT_COUNT("EC_KEY", r); REF_ASSERT_ISNT(i < 2); return ((i > 1) ? 1 : 0); } ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey) { return eckey->engine; } int EC_KEY_generate_key(EC_KEY *eckey) { if (eckey == NULL || eckey->group == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } if (eckey->meth->keygen != NULL) { int ret; ret = eckey->meth->keygen(eckey); if (ret == 1) eckey->dirty_cnt++; return ret; } ERR_raise(ERR_LIB_EC, EC_R_OPERATION_NOT_SUPPORTED); return 0; } int ossl_ec_key_gen(EC_KEY *eckey) { int ret; ret = eckey->group->meth->keygen(eckey); if (ret == 1) eckey->dirty_cnt++; return ret; } /* * Refer: FIPS 140-3 IG 10.3.A Additional Comment 1 * Perform a KAT by duplicating the public key generation. * * NOTE: This issue requires a background understanding, provided in a separate * document; the current IG 10.3.A AC1 is insufficient regarding the PCT for * the key agreement scenario. * * Currently IG 10.3.A requires PCT in the mode of use prior to use of the * key pair, citing the PCT defined in the associated standard. For key * agreement, the only PCT defined in SP 800-56A is that of Section 5.6.2.4: * the comparison of the original public key to a newly calculated public key. */ static int ecdsa_keygen_knownanswer_test(EC_KEY *eckey, BN_CTX *ctx, OSSL_CALLBACK *cb, void *cbarg) { int len, ret = 0; OSSL_SELF_TEST *st = NULL; unsigned char bytes[512] = {0}; EC_POINT *pub_key2 = EC_POINT_new(eckey->group); if (pub_key2 == NULL) return 0; st = OSSL_SELF_TEST_new(cb, cbarg); if (st == NULL) return 0; OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT_KAT, OSSL_SELF_TEST_DESC_PCT_ECDSA); /* pub_key = priv_key * G (where G is a point on the curve) */ if (!EC_POINT_mul(eckey->group, pub_key2, eckey->priv_key, NULL, NULL, ctx)) goto err; if (BN_num_bytes(pub_key2->X) > (int)sizeof(bytes)) goto err; len = BN_bn2bin(pub_key2->X, bytes); if (OSSL_SELF_TEST_oncorrupt_byte(st, bytes) && BN_bin2bn(bytes, len, pub_key2->X) == NULL) goto err; ret = !EC_POINT_cmp(eckey->group, eckey->pub_key, pub_key2, ctx); err: OSSL_SELF_TEST_onend(st, ret); OSSL_SELF_TEST_free(st); EC_POINT_free(pub_key2); return ret; } /* * ECC Key generation. * See SP800-56AR3 5.6.1.2.2 "Key Pair Generation by Testing Candidates" * * Params: * libctx A context containing an optional self test callback. * eckey An EC key object that contains domain params. The generated keypair * is stored in this object. * pairwise_test Set to non zero to perform a pairwise test. If the test * fails then the keypair is not generated, * Returns 1 if the keypair was generated or 0 otherwise. */ static int ec_generate_key(EC_KEY *eckey, int pairwise_test) { int ok = 0; BIGNUM *priv_key = NULL; const BIGNUM *tmp = NULL; BIGNUM *order = NULL; EC_POINT *pub_key = NULL; const EC_GROUP *group = eckey->group; BN_CTX *ctx = BN_CTX_secure_new_ex(eckey->libctx); int sm2 = EC_KEY_get_flags(eckey) & EC_FLAG_SM2_RANGE ? 1 : 0; if (ctx == NULL) goto err; if (eckey->priv_key == NULL) { priv_key = BN_secure_new(); if (priv_key == NULL) goto err; } else priv_key = eckey->priv_key; /* * Steps (1-2): Check domain parameters and security strength. * These steps must be done by the user. This would need to be * stated in the security policy. */ tmp = EC_GROUP_get0_order(group); if (tmp == NULL) goto err; /* * Steps (3-7): priv_key = DRBG_RAND(order_n_bits) (range [1, n-1]). * Although this is slightly different from the standard, it is effectively * equivalent as it gives an unbiased result ranging from 1..n-1. It is also * faster as the standard needs to retry more often. Also doing * 1 + rand[0..n-2] would effect the way that tests feed dummy entropy into * rand so the simpler backward compatible method has been used here. */ /* range of SM2 private key is [1, n-1) */ if (sm2) { order = BN_new(); if (order == NULL || !BN_sub(order, tmp, BN_value_one())) goto err; } else { order = BN_dup(tmp); if (order == NULL) goto err; } do if (!BN_priv_rand_range_ex(priv_key, order, 0, ctx)) goto err; while (BN_is_zero(priv_key)) ; if (eckey->pub_key == NULL) { pub_key = EC_POINT_new(group); if (pub_key == NULL) goto err; } else pub_key = eckey->pub_key; /* Step (8) : pub_key = priv_key * G (where G is a point on the curve) */ if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx)) goto err; eckey->priv_key = priv_key; eckey->pub_key = pub_key; priv_key = NULL; pub_key = NULL; eckey->dirty_cnt++; #ifdef FIPS_MODULE pairwise_test = 1; #endif /* FIPS_MODULE */ ok = 1; if (pairwise_test) { OSSL_CALLBACK *cb = NULL; void *cbarg = NULL; OSSL_SELF_TEST_get_callback(eckey->libctx, &cb, &cbarg); ok = ecdsa_keygen_pairwise_test(eckey, cb, cbarg) && ecdsa_keygen_knownanswer_test(eckey, ctx, cb, cbarg); } err: /* Step (9): If there is an error return an invalid keypair. */ if (!ok) { ossl_set_error_state(OSSL_SELF_TEST_TYPE_PCT); BN_clear(eckey->priv_key); if (eckey->pub_key != NULL) EC_POINT_set_to_infinity(group, eckey->pub_key); } EC_POINT_free(pub_key); BN_clear_free(priv_key); BN_CTX_free(ctx); BN_free(order); return ok; } #ifndef FIPS_MODULE /* * This is similar to ec_generate_key(), except it uses an ikm to * derive the private key. */ int ossl_ec_generate_key_dhkem(EC_KEY *eckey, const unsigned char *ikm, size_t ikmlen) { int ok = 0; if (eckey->priv_key == NULL) { eckey->priv_key = BN_secure_new(); if (eckey->priv_key == NULL) goto err; } if (ossl_ec_dhkem_derive_private(eckey, eckey->priv_key, ikm, ikmlen) <= 0) goto err; if (eckey->pub_key == NULL) { eckey->pub_key = EC_POINT_new(eckey->group); if (eckey->pub_key == NULL) goto err; } if (!ossl_ec_key_simple_generate_public_key(eckey)) goto err; ok = 1; err: if (!ok) { BN_clear_free(eckey->priv_key); eckey->priv_key = NULL; if (eckey->pub_key != NULL) EC_POINT_set_to_infinity(eckey->group, eckey->pub_key); } return ok; } #endif int ossl_ec_key_simple_generate_key(EC_KEY *eckey) { return ec_generate_key(eckey, 0); } int ossl_ec_key_simple_generate_public_key(EC_KEY *eckey) { int ret; BN_CTX *ctx = BN_CTX_new_ex(eckey->libctx); if (ctx == NULL) return 0; /* * See SP800-56AR3 5.6.1.2.2: Step (8) * pub_key = priv_key * G (where G is a point on the curve) */ ret = EC_POINT_mul(eckey->group, eckey->pub_key, eckey->priv_key, NULL, NULL, ctx); BN_CTX_free(ctx); if (ret == 1) eckey->dirty_cnt++; return ret; } int EC_KEY_check_key(const EC_KEY *eckey) { if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } if (eckey->group->meth->keycheck == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } return eckey->group->meth->keycheck(eckey); } /* * Check the range of the EC public key. * See SP800-56A R3 Section 5.6.2.3.3 (Part 2) * i.e. * - If q = odd prime p: Verify that xQ and yQ are integers in the * interval[0, p - 1], OR * - If q = 2m: Verify that xQ and yQ are bit strings of length m bits. * Returns 1 if the public key has a valid range, otherwise it returns 0. */ static int ec_key_public_range_check(BN_CTX *ctx, const EC_KEY *key) { int ret = 0; BIGNUM *x, *y; BN_CTX_start(ctx); x = BN_CTX_get(ctx); y = BN_CTX_get(ctx); if (y == NULL) goto err; if (!EC_POINT_get_affine_coordinates(key->group, key->pub_key, x, y, ctx)) goto err; if (EC_GROUP_get_field_type(key->group) == NID_X9_62_prime_field) { if (BN_is_negative(x) || BN_cmp(x, key->group->field) >= 0 || BN_is_negative(y) || BN_cmp(y, key->group->field) >= 0) { goto err; } } else { int m = EC_GROUP_get_degree(key->group); if (BN_num_bits(x) > m || BN_num_bits(y) > m) { goto err; } } ret = 1; err: BN_CTX_end(ctx); return ret; } /* * ECC Partial Public-Key Validation as specified in SP800-56A R3 * Section 5.6.2.3.4 ECC Partial Public-Key Validation Routine. */ int ossl_ec_key_public_check_quick(const EC_KEY *eckey, BN_CTX *ctx) { if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } /* 5.6.2.3.3 (Step 1): Q != infinity */ if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) { ERR_raise(ERR_LIB_EC, EC_R_POINT_AT_INFINITY); return 0; } /* 5.6.2.3.3 (Step 2) Test if the public key is in range */ if (!ec_key_public_range_check(ctx, eckey)) { ERR_raise(ERR_LIB_EC, EC_R_COORDINATES_OUT_OF_RANGE); return 0; } /* 5.6.2.3.3 (Step 3) is the pub_key on the elliptic curve */ if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) { ERR_raise(ERR_LIB_EC, EC_R_POINT_IS_NOT_ON_CURVE); return 0; } return 1; } /* * ECC Key validation as specified in SP800-56A R3. * Section 5.6.2.3.3 ECC Full Public-Key Validation Routine. */ int ossl_ec_key_public_check(const EC_KEY *eckey, BN_CTX *ctx) { int ret = 0; EC_POINT *point = NULL; const BIGNUM *order = NULL; const BIGNUM *cofactor = EC_GROUP_get0_cofactor(eckey->group); if (!ossl_ec_key_public_check_quick(eckey, ctx)) return 0; if (cofactor != NULL && BN_is_one(cofactor)) { /* Skip the unnecessary expensive computation for curves with cofactor of 1. */ return 1; } point = EC_POINT_new(eckey->group); if (point == NULL) return 0; order = eckey->group->order; if (BN_is_zero(order)) { ERR_raise(ERR_LIB_EC, EC_R_INVALID_GROUP_ORDER); goto err; } /* 5.6.2.3.3 (Step 4) : pub_key * order is the point at infinity. */ if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) { ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); goto err; } if (!EC_POINT_is_at_infinity(eckey->group, point)) { ERR_raise(ERR_LIB_EC, EC_R_WRONG_ORDER); goto err; } ret = 1; err: EC_POINT_free(point); return ret; } /* * ECC Key validation as specified in SP800-56A R3. * Section 5.6.2.1.2 Owner Assurance of Private-Key Validity * The private key is in the range [1, order-1] */ int ossl_ec_key_private_check(const EC_KEY *eckey) { if (eckey == NULL || eckey->group == NULL || eckey->priv_key == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } if (BN_cmp(eckey->priv_key, BN_value_one()) < 0 || BN_cmp(eckey->priv_key, eckey->group->order) >= 0) { ERR_raise(ERR_LIB_EC, EC_R_INVALID_PRIVATE_KEY); return 0; } return 1; } /* * ECC Key validation as specified in SP800-56A R3. * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency (b) * Check if generator * priv_key = pub_key */ int ossl_ec_key_pairwise_check(const EC_KEY *eckey, BN_CTX *ctx) { int ret = 0; EC_POINT *point = NULL; if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL || eckey->priv_key == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } point = EC_POINT_new(eckey->group); if (point == NULL) goto err; if (!EC_POINT_mul(eckey->group, point, eckey->priv_key, NULL, NULL, ctx)) { ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB); goto err; } if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) { ERR_raise(ERR_LIB_EC, EC_R_INVALID_PRIVATE_KEY); goto err; } ret = 1; err: EC_POINT_free(point); return ret; } /* * ECC Key validation as specified in SP800-56A R3. * Section 5.6.2.3.3 ECC Full Public-Key Validation * Section 5.6.2.1.2 Owner Assurance of Private-Key Validity * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency * NOTES: * Before calling this method in fips mode, there should be an assurance that * an approved elliptic-curve group is used. * Returns 1 if the key is valid, otherwise it returns 0. */ int ossl_ec_key_simple_check_key(const EC_KEY *eckey) { int ok = 0; BN_CTX *ctx = NULL; if (eckey == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL) return 0; if (!ossl_ec_key_public_check(eckey, ctx)) goto err; if (eckey->priv_key != NULL) { if (!ossl_ec_key_private_check(eckey) || !ossl_ec_key_pairwise_check(eckey, ctx)) goto err; } ok = 1; err: BN_CTX_free(ctx); return ok; } int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x, BIGNUM *y) { BN_CTX *ctx = NULL; BIGNUM *tx, *ty; EC_POINT *point = NULL; int ok = 0; if (key == NULL || key->group == NULL || x == NULL || y == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER); return 0; } ctx = BN_CTX_new_ex(key->libctx); if (ctx == NULL) return 0; BN_CTX_start(ctx); point = EC_POINT_new(key->group); if (point == NULL) goto err; tx = BN_CTX_get(ctx); ty = BN_CTX_get(ctx); if (ty == NULL) goto err; if (!EC_POINT_set_affine_coordinates(key->group, point, x, y, ctx)) goto err; if (!EC_POINT_get_affine_coordinates(key->group, point, tx, ty, ctx)) goto err; /* * Check if retrieved coordinates match originals. The range check is done * inside EC_KEY_check_key(). */ if (BN_cmp(x, tx) || BN_cmp(y, ty)) { ERR_raise(ERR_LIB_EC, EC_R_COORDINATES_OUT_OF_RANGE); goto err; } /* EC_KEY_set_public_key updates dirty_cnt */ if (!EC_KEY_set_public_key(key, point)) goto err; if (EC_KEY_check_key(key) == 0) goto err; ok = 1; err: BN_CTX_end(ctx); BN_CTX_free(ctx); EC_POINT_free(point); return ok; } OSSL_LIB_CTX *ossl_ec_key_get_libctx(const EC_KEY *key) { return key->libctx; } const char *ossl_ec_key_get0_propq(const EC_KEY *key) { return key->propq; } void ossl_ec_key_set0_libctx(EC_KEY *key, OSSL_LIB_CTX *libctx) { key->libctx = libctx; /* Do we need to propagate this to the group? */ } const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; } int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) { if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0) return 0; EC_GROUP_free(key->group); key->group = EC_GROUP_dup(group); if (key->group != NULL && EC_GROUP_get_curve_name(key->group) == NID_sm2) EC_KEY_set_flags(key, EC_FLAG_SM2_RANGE); key->dirty_cnt++; return (key->group == NULL) ? 0 : 1; } const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) { return key->priv_key; } int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) { int fixed_top; const BIGNUM *order = NULL; BIGNUM *tmp_key = NULL; if (key->group == NULL || key->group->meth == NULL) return 0; /* * Not only should key->group be set, but it should also be in a valid * fully initialized state. * * Specifically, to operate in constant time, we need that the group order * is set, as we use its length as the fixed public size of any scalar used * as an EC private key. */ order = EC_GROUP_get0_order(key->group); if (order == NULL || BN_is_zero(order)) return 0; /* This should never happen */ if (key->group->meth->set_private != NULL && key->group->meth->set_private(key, priv_key) == 0) return 0; if (key->meth->set_private != NULL && key->meth->set_private(key, priv_key) == 0) return 0; /* * Return `0` to comply with legacy behavior for this function, see * https://github.com/openssl/openssl/issues/18744#issuecomment-1195175696 */ if (priv_key == NULL) { BN_clear_free(key->priv_key); key->priv_key = NULL; return 0; /* intentional for legacy compatibility */ } /* * We should never leak the bit length of the secret scalar in the key, * so we always set the `BN_FLG_CONSTTIME` flag on the internal `BIGNUM` * holding the secret scalar. * * This is important also because `BN_dup()` (and `BN_copy()`) do not * propagate the `BN_FLG_CONSTTIME` flag from the source `BIGNUM`, and * this brings an extra risk of inadvertently losing the flag, even when * the caller specifically set it. * * The propagation has been turned on and off a few times in the past * years because in some conditions has shown unintended consequences in * some code paths, so at the moment we can't fix this in the BN layer. * * In `EC_KEY_set_private_key()` we can work around the propagation by * manually setting the flag after `BN_dup()` as we know for sure that * inside the EC module the `BN_FLG_CONSTTIME` is always treated * correctly and should not generate unintended consequences. * * 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 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. */ tmp_key = BN_dup(priv_key); if (tmp_key == NULL) return 0; BN_set_flags(tmp_key, BN_FLG_CONSTTIME); fixed_top = bn_get_top(order) + 2; if (bn_wexpand(tmp_key, fixed_top) == NULL) { BN_clear_free(tmp_key); return 0; } BN_clear_free(key->priv_key); key->priv_key = tmp_key; key->dirty_cnt++; return 1; } const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) { return key->pub_key; } int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) { if (key->meth->set_public != NULL && key->meth->set_public(key, pub_key) == 0) return 0; EC_POINT_free(key->pub_key); key->pub_key = EC_POINT_dup(pub_key, key->group); key->dirty_cnt++; return (key->pub_key == NULL) ? 0 : 1; } unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; } void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) { key->enc_flag = flags; } point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) { return key->conv_form; } void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) { key->conv_form = cform; if (key->group != NULL) EC_GROUP_set_point_conversion_form(key->group, cform); } void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) { if (key->group != NULL) EC_GROUP_set_asn1_flag(key->group, flag); } #ifndef OPENSSL_NO_DEPRECATED_3_0 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx) { if (key->group == NULL) return 0; return EC_GROUP_precompute_mult(key->group, ctx); } #endif int EC_KEY_get_flags(const EC_KEY *key) { return key->flags; } void EC_KEY_set_flags(EC_KEY *key, int flags) { key->flags |= flags; key->dirty_cnt++; } void EC_KEY_clear_flags(EC_KEY *key, int flags) { key->flags &= ~flags; key->dirty_cnt++; } int EC_KEY_decoded_from_explicit_params(const EC_KEY *key) { if (key == NULL || key->group == NULL) return -1; return key->group->decoded_from_explicit_params; } size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form, unsigned char **pbuf, BN_CTX *ctx) { if (key == NULL || key->pub_key == NULL || key->group == NULL) return 0; return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx); } int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len, BN_CTX *ctx) { if (key == NULL || key->group == NULL) return 0; if (key->pub_key == NULL) key->pub_key = EC_POINT_new(key->group); if (key->pub_key == NULL) return 0; if (EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx) == 0) return 0; key->dirty_cnt++; /* * Save the point conversion form. * For non-custom curves the first octet of the buffer (excluding * the last significant bit) contains the point conversion form. * EC_POINT_oct2point() has already performed sanity checking of * the buffer so we know it is valid. */ if ((key->group->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) key->conv_form = (point_conversion_form_t)(buf[0] & ~0x01); return 1; } size_t EC_KEY_priv2oct(const EC_KEY *eckey, unsigned char *buf, size_t len) { if (eckey->group == NULL || eckey->group->meth == NULL) return 0; if (eckey->group->meth->priv2oct == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } return eckey->group->meth->priv2oct(eckey, buf, len); } size_t ossl_ec_key_simple_priv2oct(const EC_KEY *eckey, unsigned char *buf, size_t len) { size_t buf_len; buf_len = (EC_GROUP_order_bits(eckey->group) + 7) / 8; if (eckey->priv_key == NULL) return 0; if (buf == NULL) return buf_len; else if (len < buf_len) return 0; /* Octetstring may need leading zeros if BN is to short */ if (BN_bn2binpad(eckey->priv_key, buf, buf_len) == -1) { ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL); return 0; } return buf_len; } int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len) { int ret; if (eckey->group == NULL || eckey->group->meth == NULL) return 0; if (eckey->group->meth->oct2priv == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } ret = eckey->group->meth->oct2priv(eckey, buf, len); if (ret == 1) eckey->dirty_cnt++; return ret; } int ossl_ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len) { if (eckey->priv_key == NULL) eckey->priv_key = BN_secure_new(); if (eckey->priv_key == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB); return 0; } if (BN_bin2bn(buf, len, eckey->priv_key) == NULL) { ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB); return 0; } eckey->dirty_cnt++; return 1; } size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf) { size_t len; unsigned char *buf; len = EC_KEY_priv2oct(eckey, NULL, 0); if (len == 0) return 0; if ((buf = OPENSSL_malloc(len)) == NULL) return 0; len = EC_KEY_priv2oct(eckey, buf, len); if (len == 0) { OPENSSL_free(buf); return 0; } *pbuf = buf; return len; } int EC_KEY_can_sign(const EC_KEY *eckey) { if (eckey->group == NULL || eckey->group->meth == NULL || (eckey->group->meth->flags & EC_FLAGS_NO_SIGN)) return 0; return 1; } /* * FIPS 140-2 IG 9.9 AS09.33 * Perform a sign/verify operation. * * NOTE: When generating keys for key-agreement schemes - FIPS 140-2 IG 9.9 * states that no additional pairwise tests are required (apart from the tests * specified in SP800-56A) when generating keys. Hence pairwise ECDH tests are * omitted here. */ static int ecdsa_keygen_pairwise_test(EC_KEY *eckey, OSSL_CALLBACK *cb, void *cbarg) { int ret = 0; unsigned char dgst[16] = {0}; int dgst_len = (int)sizeof(dgst); ECDSA_SIG *sig = NULL; OSSL_SELF_TEST *st = NULL; st = OSSL_SELF_TEST_new(cb, cbarg); if (st == NULL) return 0; OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT, OSSL_SELF_TEST_DESC_PCT_ECDSA); sig = ECDSA_do_sign(dgst, dgst_len, eckey); if (sig == NULL) goto err; OSSL_SELF_TEST_oncorrupt_byte(st, dgst); if (ECDSA_do_verify(dgst, dgst_len, sig, eckey) != 1) goto err; ret = 1; err: OSSL_SELF_TEST_onend(st, ret); OSSL_SELF_TEST_free(st); ECDSA_SIG_free(sig); return ret; }