/*
* Copyright 2002-2019 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 <openssl/opensslconf.h> /* To see if OPENSSL_NO_EC is defined */
#include "testutil.h"
#ifndef OPENSSL_NO_EC
# include <openssl/evp.h>
# include <openssl/bn.h>
# include <openssl/ec.h>
# include <openssl/rand.h>
# include "internal/nelem.h"
# include "ecdsatest.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 use_fake = 0;
static const char *numbers[2];
static size_t crv_len = 0;
static EC_builtin_curve *curves = NULL;
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(unsigned char *buf, int num)
{
int ret = 0;
static int fbytes_counter = 0;
BIGNUM *tmp = NULL;
if (use_fake == 0)
return old_rand->bytes(buf, num);
use_fake = 0;
if (!TEST_ptr(tmp = BN_new())
|| !TEST_int_lt(fbytes_counter, OSSL_NELEM(numbers))
|| !TEST_true(BN_hex2bn(&tmp, numbers[fbytes_counter]))
/* tmp might need leading zeros so pad it out */
|| !TEST_int_le(BN_num_bytes(tmp), num)
|| !TEST_true(BN_bn2binpad(tmp, buf, num)))
goto err;
fbytes_counter = (fbytes_counter + 1) % OSSL_NELEM(numbers);
ret = 1;
err:
BN_free(tmp);
return ret;
}
/*-
* This function hijacks the RNG to feed it the chosen ECDSA key and nonce.
* The ECDSA KATs are from:
* - the X9.62 draft (4)
* - NIST CAVP (720)
*
* It uses the low-level ECDSA_sign_setup instead of EVP to control the RNG.
* NB: This is not how applications should use ECDSA; this is only for testing.
*
* Tests the library can successfully:
* - generate public keys that matches those KATs
* - create ECDSA signatures that match those KATs
* - accept those signatures as valid
*/
static int x9_62_tests(int n)
{
int nid, md_nid, ret = 0;
const char *r_in = NULL, *s_in = NULL, *tbs = NULL;
unsigned char *pbuf = NULL, *qbuf = NULL, *message = NULL;
unsigned char digest[EVP_MAX_MD_SIZE];
unsigned int dgst_len = 0;
long q_len, msg_len = 0;
size_t p_len;
EVP_MD_CTX *mctx = NULL;
EC_KEY *key = NULL;
ECDSA_SIG *signature = NULL;
BIGNUM *r = NULL, *s = NULL;
BIGNUM *kinv = NULL, *rp = NULL;
const BIGNUM *sig_r = NULL, *sig_s = NULL;
nid = ecdsa_cavs_kats[n].nid;
md_nid = ecdsa_cavs_kats[n].md_nid;
r_in = ecdsa_cavs_kats[n].r;
s_in = ecdsa_cavs_kats[n].s;
tbs = ecdsa_cavs_kats[n].msg;
numbers[0] = ecdsa_cavs_kats[n].d;
numbers[1] = ecdsa_cavs_kats[n].k;
TEST_info("ECDSA KATs for curve %s", OBJ_nid2sn(nid));
if (!TEST_ptr(mctx = EVP_MD_CTX_new())
/* get the message digest */
|| !TEST_ptr(message = OPENSSL_hexstr2buf(tbs, &msg_len))
|| !TEST_true(EVP_DigestInit_ex(mctx, EVP_get_digestbynid(md_nid), NULL))
|| !TEST_true(EVP_DigestUpdate(mctx, message, msg_len))
|| !TEST_true(EVP_DigestFinal_ex(mctx, digest, &dgst_len))
/* create the key */
|| !TEST_ptr(key = EC_KEY_new_by_curve_name(nid))
/* load KAT variables */
|| !TEST_ptr(r = BN_new())
|| !TEST_ptr(s = BN_new())
|| !TEST_true(BN_hex2bn(&r, r_in))
|| !TEST_true(BN_hex2bn(&s, s_in))
/* swap the RNG source */
|| !TEST_true(change_rand()))
goto err;
/* public key must match KAT */
use_fake = 1;
if (!TEST_true(EC_KEY_generate_key(key))
|| !TEST_true(p_len = EC_KEY_key2buf(key, POINT_CONVERSION_UNCOMPRESSED,
&pbuf, NULL))
|| !TEST_ptr(qbuf = OPENSSL_hexstr2buf(ecdsa_cavs_kats[n].Q, &q_len))
|| !TEST_int_eq(q_len, p_len)
|| !TEST_mem_eq(qbuf, q_len, pbuf, p_len))
goto err;
/* create the signature via ECDSA_sign_setup to avoid use of ECDSA nonces */
use_fake = 1;
if (!TEST_true(ECDSA_sign_setup(key, NULL, &kinv, &rp))
|| !TEST_ptr(signature = ECDSA_do_sign_ex(digest, dgst_len,
kinv, rp, key))
/* verify the signature */
|| !TEST_int_eq(ECDSA_do_verify(digest, dgst_len, signature, key), 1))
goto err;
/* compare the created signature with the expected signature */
ECDSA_SIG_get0(signature, &sig_r, &sig_s);
if (!TEST_BN_eq(sig_r, r)
|| !TEST_BN_eq(sig_s, s))
goto err;
ret = 1;
err:
/* restore the RNG source */
if (!TEST_true(restore_rand()))
ret = 0;
OPENSSL_free(message);
OPENSSL_free(pbuf);
OPENSSL_free(qbuf);
EC_KEY_free(key);
ECDSA_SIG_free(signature);
BN_free(r);
BN_free(s);
EVP_MD_CTX_free(mctx);
BN_clear_free(kinv);
BN_clear_free(rp);
return ret;
}
/*-
* Positive and negative ECDSA testing through EVP interface:
* - EVP_DigestSign (this is the one-shot version)
* - EVP_DigestVerify
*
* Tests the library can successfully:
* - create a key
* - create a signature
* - accept that signature
* - reject that signature with a different public key
* - reject that signature if its length is not correct
* - reject that signature after modifying the message
* - accept that signature after un-modifying the message
* - reject that signature after modifying the signature
* - accept that signature after un-modifying the signature
*/
static int test_builtin(int n)
{
EC_KEY *eckey_neg = NULL, *eckey = NULL;
unsigned char dirt, offset, tbs[128];
unsigned char *sig = NULL;
EVP_PKEY *pkey_neg = NULL, *pkey = NULL;
EVP_MD_CTX *mctx = NULL;
size_t sig_len;
int nid, ret = 0;
nid = curves[n].nid;
/* skip built-in curves where ord(G) is not prime */
if (nid == NID_ipsec4 || nid == NID_ipsec3) {
TEST_info("skipped: ECDSA unsupported for curve %s", OBJ_nid2sn(nid));
return 1;
}
TEST_info("testing ECDSA for curve %s", OBJ_nid2sn(nid));
if (!TEST_ptr(mctx = EVP_MD_CTX_new())
/* get some random message data */
|| !TEST_true(RAND_bytes(tbs, sizeof(tbs)))
/* real key */
|| !TEST_ptr(eckey = EC_KEY_new_by_curve_name(nid))
|| !TEST_true(EC_KEY_generate_key(eckey))
|| !TEST_ptr(pkey = EVP_PKEY_new())
|| !TEST_true(EVP_PKEY_assign_EC_KEY(pkey, eckey))
/* fake key for negative testing */
|| !TEST_ptr(eckey_neg = EC_KEY_new_by_curve_name(nid))
|| !TEST_true(EC_KEY_generate_key(eckey_neg))
|| !TEST_ptr(pkey_neg = EVP_PKEY_new())
|| !TEST_true(EVP_PKEY_assign_EC_KEY(pkey_neg, eckey_neg)))
goto err;
sig_len = ECDSA_size(eckey);
if (!TEST_ptr(sig = OPENSSL_malloc(sig_len))
/* create a signature */
|| !TEST_true(EVP_DigestSignInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_true(EVP_DigestSign(mctx, sig, &sig_len, tbs, sizeof(tbs)))
|| !TEST_int_le(sig_len, ECDSA_size(eckey))
/* negative test, verify with wrong key, 0 return */
|| !TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey_neg))
|| !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 0)
/* negative test, verify with wrong signature length, -1 return */
|| !TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len - 1, tbs, sizeof(tbs)), -1)
/* positive test, verify with correct key, 1 return */
|| !TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1))
goto err;
/* muck with the message, test it fails with 0 return */
tbs[0] ^= 1;
if (!TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 0))
goto err;
/* un-muck and test it verifies */
tbs[0] ^= 1;
if (!TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1))
goto err;
/*-
* Muck with the ECDSA signature. The DER encoding is one of:
* - 30 LL 02 ..
* - 30 81 LL 02 ..
*
* - Sometimes this mucks with the high level DER sequence wrapper:
* in that case, DER-parsing of the whole signature should fail.
*
* - Sometimes this mucks with the DER-encoding of ECDSA.r:
* in that case, DER-parsing of ECDSA.r should fail.
*
* - Sometimes this mucks with the DER-encoding of ECDSA.s:
* in that case, DER-parsing of ECDSA.s should fail.
*
* - Sometimes this mucks with ECDSA.r:
* in that case, the signature verification should fail.
*
* - Sometimes this mucks with ECDSA.s:
* in that case, the signature verification should fail.
*
* The usual case is changing the integer value of ECDSA.r or ECDSA.s.
* Because the ratio of DER overhead to signature bytes is small.
* So most of the time it will be one of the last two cases.
*
* In any case, EVP_PKEY_verify should not return 1 for valid.
*/
offset = tbs[0] % sig_len;
dirt = tbs[1] ? tbs[1] : 1;
sig[offset] ^= dirt;
if (!TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_int_ne(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1))
goto err;
/* un-muck and test it verifies */
sig[offset] ^= dirt;
if (!TEST_true(EVP_MD_CTX_reset(mctx))
|| !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
|| !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1))
goto err;
ret = 1;
err:
EVP_PKEY_free(pkey);
EVP_PKEY_free(pkey_neg);
EVP_MD_CTX_free(mctx);
OPENSSL_free(sig);
return ret;
}
#endif
int setup_tests(void)
{
#ifdef OPENSSL_NO_EC
TEST_note("Elliptic curves are disabled.");
#else
/* 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)))
return 0;
ADD_ALL_TESTS(test_builtin, crv_len);
ADD_ALL_TESTS(x9_62_tests, OSSL_NELEM(ecdsa_cavs_kats));
#endif
return 1;
}
void cleanup_tests(void)
{
#ifndef OPENSSL_NO_EC
OPENSSL_free(curves);
#endif
}