ecdsatest.c
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/*
* Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
*
* Licensed under the OpenSSL license (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
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_EC is defined */
# include "testutil.h"
#ifndef OPENSSL_NO_EC
# include <openssl/crypto.h>
# include <openssl/bio.h>
# include <openssl/evp.h>
# include <openssl/bn.h>
# include <openssl/ec.h>
# ifndef OPENSSL_NO_ENGINE
# include <openssl/engine.h>
# endif
# include <openssl/err.h>
# include <openssl/rand.h>
/* functions to change the RAND_METHOD */
static int fbytes(unsigned char *buf, int num);
static RAND_METHOD fake_rand;
static const RAND_METHOD *old_rand;
static int change_rand(void)
{
/* save old rand method */
if (!TEST_ptr(old_rand = RAND_get_rand_method()))
return 0;
fake_rand = *old_rand;
/* use own random function */
fake_rand.bytes = fbytes;
/* set new RAND_METHOD */
if (!TEST_true(RAND_set_rand_method(&fake_rand)))
return 0;
return 1;
}
static int restore_rand(void)
{
if (!TEST_true(RAND_set_rand_method(old_rand)))
return 0;
return 1;
}
static int fbytes_counter = 0, use_fake = 0;
static const char *numbers[8] = {
"651056770906015076056810763456358567190100156695615665659",
"6140507067065001063065065565667405560006161556565665656654",
"8763001015071075675010661307616710783570106710677817767166"
"71676178726717",
"7000000175690566466555057817571571075705015757757057795755"
"55657156756655",
"1275552191113212300012030439187146164646146646466749494799",
"1542725565216523985789236956265265265235675811949404040041",
"1456427555219115346513212300075341203043918714616464614664"
"64667494947990",
"1712787255652165239672857892369562652652652356758119494040"
"40041670216363"
};
static int fbytes(unsigned char *buf, int num)
{
int ret = 0;
BIGNUM *tmp = NULL;
if (use_fake == 0)
return old_rand->bytes(buf, num);
use_fake = 0;
if (fbytes_counter >= 8)
return 0;
if (!TEST_ptr(tmp = BN_new()))
return 0;
if (!TEST_true(BN_dec2bn(&tmp, numbers[fbytes_counter]))) {
BN_free(tmp);
return 0;
}
fbytes_counter++;
if (TEST_int_eq(BN_num_bytes(tmp), num)
&& TEST_true(BN_bn2bin(tmp, buf)))
ret = 1;
BN_free(tmp);
return ret;
}
/* some tests from the X9.62 draft */
static int x9_62_test_internal(int nid, const char *r_in, const char *s_in)
{
int ret = 0;
const char message[] = "abc";
unsigned char digest[20];
unsigned int dgst_len = 0;
EVP_MD_CTX *md_ctx;
EC_KEY *key = NULL;
ECDSA_SIG *signature = NULL;
BIGNUM *r = NULL, *s = NULL;
BIGNUM *kinv = NULL, *rp = NULL;
const BIGNUM *sig_r, *sig_s;
if (!TEST_ptr(md_ctx = EVP_MD_CTX_new()))
goto x962_int_err;
/* get the message digest */
if (!TEST_true(EVP_DigestInit(md_ctx, EVP_sha1()))
|| !TEST_true(EVP_DigestUpdate(md_ctx, (const void *)message, 3))
|| !TEST_true(EVP_DigestFinal(md_ctx, digest, &dgst_len)))
goto x962_int_err;
TEST_info("testing %s", OBJ_nid2sn(nid));
/* create the key */
if (!TEST_ptr(key = EC_KEY_new_by_curve_name(nid)))
goto x962_int_err;
use_fake = 1;
if (!TEST_true(EC_KEY_generate_key(key)))
goto x962_int_err;
/* create the signature */
use_fake = 1;
/* Use ECDSA_sign_setup to avoid use of ECDSA nonces */
if (!TEST_true(ECDSA_sign_setup(key, NULL, &kinv, &rp)))
goto x962_int_err;
if (!TEST_ptr(signature = ECDSA_do_sign_ex(digest, 20, kinv, rp, key)))
goto x962_int_err;
/* compare the created signature with the expected signature */
if (!TEST_ptr(r = BN_new()) || !TEST_ptr(s = BN_new()))
goto x962_int_err;
if (!TEST_true(BN_dec2bn(&r, r_in)) || !TEST_true(BN_dec2bn(&s, s_in)))
goto x962_int_err;
ECDSA_SIG_get0(signature, &sig_r, &sig_s);
if (!TEST_BN_eq(sig_r, r)
|| !TEST_BN_eq(sig_s, s))
goto x962_int_err;
/* verify the signature */
if (!TEST_int_eq(ECDSA_do_verify(digest, 20, signature, key), 1))
goto x962_int_err;
ret = 1;
x962_int_err:
EC_KEY_free(key);
ECDSA_SIG_free(signature);
BN_free(r);
BN_free(s);
EVP_MD_CTX_free(md_ctx);
BN_clear_free(kinv);
BN_clear_free(rp);
return ret;
}
static int x9_62_tests(void)
{
int ret = 0;
/* set own rand method */
if (!change_rand())
goto x962_err;
if (!TEST_true(x9_62_test_internal(NID_X9_62_prime192v1,
"3342403536405981729393488334694600415596881826869351677613",
"5735822328888155254683894997897571951568553642892029982342")))
goto x962_err;
if (!TEST_true(x9_62_test_internal(NID_X9_62_prime239v1,
"3086361431751678114926225473006680188549593787585317781474"
"62058306432176",
"3238135532097973577080787768312505059318910517550078427819"
"78505179448783")))
goto x962_err;
# ifndef OPENSSL_NO_EC2M
if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb191v1,
"87194383164871543355722284926904419997237591535066528048",
"308992691965804947361541664549085895292153777025772063598")))
goto x962_err;
if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb239v1,
"2159633321041961198501834003903461262881815148684178964245"
"5876922391552",
"1970303740007316867383349976549972270528498040721988191026"
"49413465737174")))
goto x962_err;
# endif
ret = 1;
x962_err:
if (!TEST_true(restore_rand()))
ret = 0;
return ret;
}
static int test_builtin(void)
{
EC_builtin_curve *curves = NULL;
size_t crv_len = 0, n = 0;
EC_KEY *eckey = NULL, *wrong_eckey = NULL;
EC_GROUP *group;
ECDSA_SIG *ecdsa_sig = NULL, *modified_sig = NULL;
unsigned char digest[20], wrong_digest[20];
unsigned char *signature = NULL;
const unsigned char *sig_ptr;
unsigned char *sig_ptr2;
unsigned char *raw_buf = NULL;
const BIGNUM *sig_r, *sig_s;
BIGNUM *modified_r = NULL, *modified_s = NULL;
BIGNUM *unmodified_r = NULL, *unmodified_s = NULL;
unsigned int sig_len, degree, r_len, s_len, bn_len, buf_len;
int nid, ret = 0;
/* fill digest values with some random data */
if (!TEST_true(RAND_bytes(digest, 20))
|| !TEST_true(RAND_bytes(wrong_digest, 20)))
goto builtin_err;
/* create and verify a ecdsa signature with every available curve */
/* get a list of all internal curves */
crv_len = EC_get_builtin_curves(NULL, 0);
if (!TEST_ptr(curves = OPENSSL_malloc(sizeof(*curves) * crv_len))
|| !TEST_true(EC_get_builtin_curves(curves, crv_len)))
goto builtin_err;
/* now create and verify a signature for every curve */
for (n = 0; n < crv_len; n++) {
unsigned char dirt, offset;
nid = curves[n].nid;
if (nid == NID_ipsec4)
continue;
/* create new ecdsa key (== EC_KEY) */
if (!TEST_ptr(eckey = EC_KEY_new())
|| !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
|| !TEST_true(EC_KEY_set_group(eckey, group)))
goto builtin_err;
EC_GROUP_free(group);
degree = EC_GROUP_get_degree(EC_KEY_get0_group(eckey));
if (degree < 160) {
/* drop the curve */
EC_KEY_free(eckey);
eckey = NULL;
continue;
}
TEST_info("testing %s", OBJ_nid2sn(nid));
/* create key */
if (!TEST_true(EC_KEY_generate_key(eckey)))
goto builtin_err;
/* create second key */
if (!TEST_ptr(wrong_eckey = EC_KEY_new())
|| !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
|| !TEST_true(EC_KEY_set_group(wrong_eckey, group)))
goto builtin_err;
EC_GROUP_free(group);
if (!TEST_true(EC_KEY_generate_key(wrong_eckey)))
goto builtin_err;
/* check key */
if (!TEST_true(EC_KEY_check_key(eckey)))
goto builtin_err;
/* create signature */
sig_len = ECDSA_size(eckey);
if (!TEST_ptr(signature = OPENSSL_malloc(sig_len))
|| !TEST_true(ECDSA_sign(0, digest, 20, signature, &sig_len,
eckey)))
goto builtin_err;
/* verify signature */
if (!TEST_int_eq(ECDSA_verify(0, digest, 20, signature, sig_len,
eckey), 1))
goto builtin_err;
/* verify signature with the wrong key */
if (!TEST_int_ne(ECDSA_verify(0, digest, 20, signature, sig_len,
wrong_eckey), 1))
goto builtin_err;
/* wrong digest */
if (!TEST_int_ne(ECDSA_verify(0, wrong_digest, 20, signature,
sig_len, eckey), 1))
goto builtin_err;
/* wrong length */
if (!TEST_int_ne(ECDSA_verify(0, digest, 20, signature,
sig_len - 1, eckey), 1))
goto builtin_err;
/*
* Modify a single byte of the signature: to ensure we don't garble
* the ASN1 structure, we read the raw signature and modify a byte in
* one of the bignums directly.
*/
sig_ptr = signature;
if (!TEST_ptr(ecdsa_sig = d2i_ECDSA_SIG(NULL, &sig_ptr, sig_len)))
goto builtin_err;
ECDSA_SIG_get0(ecdsa_sig, &sig_r, &sig_s);
/* Store the two BIGNUMs in raw_buf. */
r_len = BN_num_bytes(sig_r);
s_len = BN_num_bytes(sig_s);
bn_len = (degree + 7) / 8;
if (!TEST_false(r_len > bn_len)
|| !TEST_false(s_len > bn_len))
goto builtin_err;
buf_len = 2 * bn_len;
if (!TEST_ptr(raw_buf = OPENSSL_zalloc(buf_len)))
goto builtin_err;
BN_bn2bin(sig_r, raw_buf + bn_len - r_len);
BN_bn2bin(sig_s, raw_buf + buf_len - s_len);
/* Modify a single byte in the buffer. */
offset = raw_buf[10] % buf_len;
dirt = raw_buf[11] ? raw_buf[11] : 1;
raw_buf[offset] ^= dirt;
/* Now read the BIGNUMs back in from raw_buf. */
if (!TEST_ptr(modified_sig = ECDSA_SIG_new()))
goto builtin_err;
if (!TEST_ptr(modified_r = BN_bin2bn(raw_buf, bn_len, NULL))
|| !TEST_ptr(modified_s = BN_bin2bn(raw_buf + bn_len,
bn_len, NULL))
|| !TEST_true(ECDSA_SIG_set0(modified_sig,
modified_r, modified_s))) {
BN_free(modified_r);
BN_free(modified_s);
goto builtin_err;
}
sig_ptr2 = signature;
sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
if (!TEST_false(ECDSA_verify(0, digest, 20, signature, sig_len, eckey)))
goto builtin_err;
/* Sanity check: undo the modification and verify signature. */
raw_buf[offset] ^= dirt;
if (!TEST_ptr(unmodified_r = BN_bin2bn(raw_buf, bn_len, NULL))
|| !TEST_ptr(unmodified_s = BN_bin2bn(raw_buf + bn_len,
bn_len, NULL))
|| !TEST_true(ECDSA_SIG_set0(modified_sig, unmodified_r,
unmodified_s))) {
BN_free(unmodified_r);
BN_free(unmodified_s);
goto builtin_err;
}
sig_ptr2 = signature;
sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
if (!TEST_true(ECDSA_verify(0, digest, 20, signature, sig_len, eckey)))
goto builtin_err;
/* cleanup */
ERR_clear_error();
OPENSSL_free(signature);
signature = NULL;
EC_KEY_free(eckey);
eckey = NULL;
EC_KEY_free(wrong_eckey);
wrong_eckey = NULL;
ECDSA_SIG_free(ecdsa_sig);
ecdsa_sig = NULL;
ECDSA_SIG_free(modified_sig);
modified_sig = NULL;
OPENSSL_free(raw_buf);
raw_buf = NULL;
}
ret = 1;
builtin_err:
EC_KEY_free(eckey);
EC_KEY_free(wrong_eckey);
ECDSA_SIG_free(ecdsa_sig);
ECDSA_SIG_free(modified_sig);
OPENSSL_free(signature);
OPENSSL_free(raw_buf);
OPENSSL_free(curves);
return ret;
}
#endif
int setup_tests(void)
{
#ifdef OPENSSL_NO_EC
TEST_note("Elliptic curves are disabled.");
#else
ADD_TEST(x9_62_tests);
ADD_TEST(test_builtin);
#endif
return 1;
}