test/ecdsatest.c

   1 /*
   2  * Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14
  15 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_EC is defined */
  16 #include "testutil.h"
  17
  18 #ifndef OPENSSL_NO_EC
  19
  20 # include <openssl/crypto.h>
  21 # include <openssl/bio.h>
  22 # include <openssl/evp.h>
  23 # include <openssl/bn.h>
  24 # include <openssl/ec.h>
  25 # ifndef OPENSSL_NO_ENGINE
  26 #  include <openssl/engine.h>
  27 # endif
  28 # include <openssl/sha.h>
  29 # include <openssl/err.h>
  30 # include <openssl/rand.h>
  31
  32 /* functions to change the RAND_METHOD */
  33 static int fbytes(unsigned char *buf, int num);
  34
  35 static RAND_METHOD fake_rand;
  36 static const RAND_METHOD *old_rand;
  37
  38 static int change_rand(void)
  39 {
  40     /* save old rand method */
  41     if (!TEST_ptr(old_rand = RAND_get_rand_method()))
  42         return 0;
  43
  44     fake_rand = *old_rand;
  45     /* use own random function */
  46     fake_rand.bytes = fbytes;
  47     /* set new RAND_METHOD */
  48     if (!TEST_true(RAND_set_rand_method(&fake_rand)))
  49         return 0;
  50     return 1;
  51 }
  52
  53 static int restore_rand(void)
  54 {
  55     if (!TEST_true(RAND_set_rand_method(old_rand)))
  56         return 0;
  57     return 1;
  58 }
  59
  60 static int fbytes_counter = 0, use_fake = 0;
  61 static const char *numbers[8] = {
  62     "651056770906015076056810763456358567190100156695615665659",
  63     "6140507067065001063065065565667405560006161556565665656654",
  64     "8763001015071075675010661307616710783570106710677817767166"
  65         "71676178726717",
  66     "7000000175690566466555057817571571075705015757757057795755"
  67         "55657156756655",
  68     "1275552191113212300012030439187146164646146646466749494799",
  69     "1542725565216523985789236956265265265235675811949404040041",
  70     "1456427555219115346513212300075341203043918714616464614664"
  71         "64667494947990",
  72     "1712787255652165239672857892369562652652652356758119494040"
  73         "40041670216363"
  74 };
  75
  76 static int fbytes(unsigned char *buf, int num)
  77 {
  78     int ret = 0;
  79     BIGNUM *tmp = NULL;
  80
  81     if (use_fake == 0)
  82         return old_rand->bytes(buf, num);
  83
  84     use_fake = 0;
  85
  86     if (fbytes_counter >= 8)
  87         return 0;
  88     if (!TEST_ptr(tmp = BN_new()))
  89         return 0;
  90     if (!TEST_true(BN_dec2bn(&tmp, numbers[fbytes_counter]))) {
  91         BN_free(tmp);
  92         return 0;
  93     }
  94     fbytes_counter++;
  95     if (TEST_int_eq(BN_num_bytes(tmp), num)
  96             && TEST_true(BN_bn2bin(tmp, buf)))
  97         ret = 1;
  98     BN_free(tmp);
  99     return ret;
 100 }
 101
 102 /* some tests from the X9.62 draft */
 103 static int x9_62_test_internal(int nid, const char *r_in, const char *s_in)
 104 {
 105     int ret = 0;
 106     const char message[] = "abc";
 107     unsigned char digest[SHA_DIGEST_LENGTH];
 108     unsigned int dgst_len = 0;
 109     EVP_MD_CTX *md_ctx;
 110     EC_KEY *key = NULL;
 111     ECDSA_SIG *signature = NULL;
 112     BIGNUM *r = NULL, *s = NULL;
 113     BIGNUM *kinv = NULL, *rp = NULL;
 114     const BIGNUM *sig_r, *sig_s;
 115
 116     if (!TEST_ptr(md_ctx = EVP_MD_CTX_new()))
 117         goto x962_int_err;
 118
 119     /* get the message digest */
 120     if (!TEST_true(EVP_DigestInit(md_ctx, EVP_sha1()))
 121         || !TEST_true(EVP_DigestUpdate(md_ctx, (const void *)message, 3))
 122         || !TEST_true(EVP_DigestFinal(md_ctx, digest, &dgst_len)))
 123         goto x962_int_err;
 124
 125     TEST_info("testing %s", OBJ_nid2sn(nid));
 126
 127     /* create the key */
 128     if (!TEST_ptr(key = EC_KEY_new_by_curve_name(nid)))
 129         goto x962_int_err;
 130     use_fake = 1;
 131     if (!TEST_true(EC_KEY_generate_key(key)))
 132         goto x962_int_err;
 133
 134     /* create the signature */
 135     use_fake = 1;
 136     /* Use ECDSA_sign_setup to avoid use of ECDSA nonces */
 137     if (!TEST_true(ECDSA_sign_setup(key, NULL, &kinv, &rp)))
 138         goto x962_int_err;
 139     if (!TEST_ptr(signature =
 140                   ECDSA_do_sign_ex(digest, SHA_DIGEST_LENGTH, kinv, rp, key)))
 141         goto x962_int_err;
 142
 143     /* compare the created signature with the expected signature */
 144     if (!TEST_ptr(r = BN_new()) || !TEST_ptr(s = BN_new()))
 145         goto x962_int_err;
 146     if (!TEST_true(BN_dec2bn(&r, r_in)) || !TEST_true(BN_dec2bn(&s, s_in)))
 147         goto x962_int_err;
 148     ECDSA_SIG_get0(signature, &sig_r, &sig_s);
 149     if (!TEST_BN_eq(sig_r, r)
 150             || !TEST_BN_eq(sig_s, s))
 151         goto x962_int_err;
 152
 153     /* verify the signature */
 154     if (!TEST_int_eq(ECDSA_do_verify(digest, SHA_DIGEST_LENGTH,
 155                                      signature, key), 1))
 156         goto x962_int_err;
 157
 158     ret = 1;
 159
 160  x962_int_err:
 161     EC_KEY_free(key);
 162     ECDSA_SIG_free(signature);
 163     BN_free(r);
 164     BN_free(s);
 165     EVP_MD_CTX_free(md_ctx);
 166     BN_clear_free(kinv);
 167     BN_clear_free(rp);
 168     return ret;
 169 }
 170
 171 static int x9_62_tests(void)
 172 {
 173     int ret = 0;
 174
 175     /* set own rand method */
 176     if (!change_rand())
 177         goto x962_err;
 178
 179     if (!TEST_true(x9_62_test_internal(NID_X9_62_prime192v1,
 180                  "3342403536405981729393488334694600415596881826869351677613",
 181                  "5735822328888155254683894997897571951568553642892029982342")))
 182         goto x962_err;
 183     if (!TEST_true(x9_62_test_internal(NID_X9_62_prime239v1,
 184                  "3086361431751678114926225473006680188549593787585317781474"
 185                              "62058306432176",
 186                  "3238135532097973577080787768312505059318910517550078427819"
 187                              "78505179448783")))
 188         goto x962_err;
 189
 190 # ifndef OPENSSL_NO_EC2M
 191     if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb191v1,
 192                  "87194383164871543355722284926904419997237591535066528048",
 193                  "308992691965804947361541664549085895292153777025772063598")))
 194         goto x962_err;
 195     if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb239v1,
 196                  "2159633321041961198501834003903461262881815148684178964245"
 197                              "5876922391552",
 198                  "1970303740007316867383349976549972270528498040721988191026"
 199                              "49413465737174")))
 200         goto x962_err;
 201 # endif
 202     ret = 1;
 203
 204  x962_err:
 205     if (!TEST_true(restore_rand()))
 206         ret = 0;
 207     return ret;
 208 }
 209
 210 static int test_builtin(void)
 211 {
 212     EC_builtin_curve *curves = NULL;
 213     size_t crv_len = 0, n = 0;
 214     EC_KEY *eckey = NULL, *wrong_eckey = NULL;
 215     EC_GROUP *group;
 216     ECDSA_SIG *ecdsa_sig = NULL, *modified_sig = NULL;
 217     unsigned char digest[SHA512_DIGEST_LENGTH];
 218     unsigned char wrong_digest[SHA512_DIGEST_LENGTH];
 219     unsigned char *signature = NULL;
 220     const unsigned char *sig_ptr;
 221     unsigned char *sig_ptr2;
 222     unsigned char *raw_buf = NULL;
 223     const BIGNUM *sig_r, *sig_s;
 224     BIGNUM *modified_r = NULL, *modified_s = NULL;
 225     BIGNUM *unmodified_r = NULL, *unmodified_s = NULL;
 226     unsigned int sig_len, degree, r_len, s_len, bn_len, buf_len;
 227     int nid, ret = 0;
 228
 229     /* fill digest values with some random data */
 230     if (!TEST_true(RAND_bytes(digest, SHA512_DIGEST_LENGTH))
 231             || !TEST_true(RAND_bytes(wrong_digest, SHA512_DIGEST_LENGTH)))
 232         goto builtin_err;
 233
 234     /* create and verify a ecdsa signature with every available curve */
 235     /* get a list of all internal curves */
 236     crv_len = EC_get_builtin_curves(NULL, 0);
 237     if (!TEST_ptr(curves = OPENSSL_malloc(sizeof(*curves) * crv_len))
 238             || !TEST_true(EC_get_builtin_curves(curves, crv_len)))
 239         goto builtin_err;
 240
 241     /* now create and verify a signature for every curve */
 242     for (n = 0; n < crv_len; n++) {
 243         unsigned char dirt, offset;
 244
 245         nid = curves[n].nid;
 246         if (nid == NID_ipsec4 || nid == NID_ipsec3)
 247             continue;
 248         /* create new ecdsa key (== EC_KEY) */
 249         if (!TEST_ptr(eckey = EC_KEY_new())
 250                 || !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
 251                 || !TEST_true(EC_KEY_set_group(eckey, group)))
 252             goto builtin_err;
 253         EC_GROUP_free(group);
 254         degree = EC_GROUP_get_degree(EC_KEY_get0_group(eckey));
 255
 256         TEST_info("testing %s", OBJ_nid2sn(nid));
 257
 258         /* create key */
 259         if (!TEST_true(EC_KEY_generate_key(eckey)))
 260             goto builtin_err;
 261         /* create second key */
 262         if (!TEST_ptr(wrong_eckey = EC_KEY_new())
 263                 || !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
 264                 || !TEST_true(EC_KEY_set_group(wrong_eckey, group)))
 265             goto builtin_err;
 266         EC_GROUP_free(group);
 267         if (!TEST_true(EC_KEY_generate_key(wrong_eckey)))
 268             goto builtin_err;
 269
 270         /* check key */
 271         if (!TEST_true(EC_KEY_check_key(eckey)))
 272             goto builtin_err;
 273
 274         /* create signature */
 275         sig_len = ECDSA_size(eckey);
 276         if (!TEST_ptr(signature = OPENSSL_malloc(sig_len))
 277                 || !TEST_true(ECDSA_sign(0, digest, SHA512_DIGEST_LENGTH,
 278                                          signature, &sig_len, eckey)))
 279             goto builtin_err;
 280
 281         /* verify signature */
 282         if (!TEST_int_eq(ECDSA_verify(0, digest, SHA512_DIGEST_LENGTH,
 283                                       signature, sig_len, eckey),
 284                          1))
 285             goto builtin_err;
 286
 287         /* verify signature with the wrong key */
 288         if (!TEST_int_ne(ECDSA_verify(0, digest, SHA512_DIGEST_LENGTH,
 289                                       signature, sig_len, wrong_eckey),
 290                          1))
 291             goto builtin_err;
 292
 293         /* wrong digest */
 294         if (!TEST_int_ne(ECDSA_verify(0, wrong_digest, SHA512_DIGEST_LENGTH,
 295                                       signature, sig_len, eckey),
 296                          1))
 297             goto builtin_err;
 298
 299         /* wrong length */
 300         if (!TEST_int_ne(ECDSA_verify(0, digest, SHA512_DIGEST_LENGTH,
 301                                       signature, sig_len - 1, eckey),
 302                          1))
 303             goto builtin_err;
 304
 305         /*
 306          * Modify a single byte of the signature: to ensure we don't garble
 307          * the ASN1 structure, we read the raw signature and modify a byte in
 308          * one of the bignums directly.
 309          */
 310         sig_ptr = signature;
 311         if (!TEST_ptr(ecdsa_sig = d2i_ECDSA_SIG(NULL, &sig_ptr, sig_len)))
 312             goto builtin_err;
 313
 314         ECDSA_SIG_get0(ecdsa_sig, &sig_r, &sig_s);
 315
 316         /* Store the two BIGNUMs in raw_buf. */
 317         r_len = BN_num_bytes(sig_r);
 318         s_len = BN_num_bytes(sig_s);
 319         bn_len = (degree + 7) / 8;
 320         if (!TEST_false(r_len > bn_len)
 321                 || !TEST_false(s_len > bn_len))
 322             goto builtin_err;
 323         buf_len = 2 * bn_len;
 324         if (!TEST_ptr(raw_buf = OPENSSL_zalloc(buf_len)))
 325             goto builtin_err;
 326         BN_bn2bin(sig_r, raw_buf + bn_len - r_len);
 327         BN_bn2bin(sig_s, raw_buf + buf_len - s_len);
 328
 329         /* Modify a single byte in the buffer. */
 330         offset = raw_buf[10] % buf_len;
 331         dirt = raw_buf[11] ? raw_buf[11] : 1;
 332         raw_buf[offset] ^= dirt;
 333
 334         /* Now read the BIGNUMs back in from raw_buf. */
 335         if (!TEST_ptr(modified_sig = ECDSA_SIG_new()))
 336             goto builtin_err;
 337         if (!TEST_ptr(modified_r = BN_bin2bn(raw_buf, bn_len, NULL))
 338                 || !TEST_ptr(modified_s = BN_bin2bn(raw_buf + bn_len,
 339                                                     bn_len, NULL))
 340                 || !TEST_true(ECDSA_SIG_set0(modified_sig,
 341                                              modified_r, modified_s))) {
 342             BN_free(modified_r);
 343             BN_free(modified_s);
 344             goto builtin_err;
 345         }
 346         sig_ptr2 = signature;
 347         sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
 348         if (!TEST_false(ECDSA_verify(0, digest, SHA512_DIGEST_LENGTH,
 349                                      signature, sig_len, eckey)))
 350             goto builtin_err;
 351
 352         /* Sanity check: undo the modification and verify signature. */
 353         raw_buf[offset] ^= dirt;
 354         if (!TEST_ptr(unmodified_r = BN_bin2bn(raw_buf, bn_len, NULL))
 355                 || !TEST_ptr(unmodified_s = BN_bin2bn(raw_buf + bn_len,
 356                                                       bn_len, NULL))
 357                 || !TEST_true(ECDSA_SIG_set0(modified_sig, unmodified_r,
 358                                              unmodified_s))) {
 359             BN_free(unmodified_r);
 360             BN_free(unmodified_s);
 361             goto builtin_err;
 362         }
 363
 364         sig_ptr2 = signature;
 365         sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
 366         if (!TEST_true(ECDSA_verify(0, digest, SHA512_DIGEST_LENGTH,
 367                                     signature, sig_len, eckey)))
 368             goto builtin_err;
 369
 370         /* cleanup */
 371         ERR_clear_error();
 372         OPENSSL_free(signature);
 373         signature = NULL;
 374         EC_KEY_free(eckey);
 375         eckey = NULL;
 376         EC_KEY_free(wrong_eckey);
 377         wrong_eckey = NULL;
 378         ECDSA_SIG_free(ecdsa_sig);
 379         ecdsa_sig = NULL;
 380         ECDSA_SIG_free(modified_sig);
 381         modified_sig = NULL;
 382         OPENSSL_free(raw_buf);
 383         raw_buf = NULL;
 384     }
 385
 386     ret = 1;
 387  builtin_err:
 388     EC_KEY_free(eckey);
 389     EC_KEY_free(wrong_eckey);
 390     ECDSA_SIG_free(ecdsa_sig);
 391     ECDSA_SIG_free(modified_sig);
 392     OPENSSL_free(signature);
 393     OPENSSL_free(raw_buf);
 394     OPENSSL_free(curves);
 395
 396     return ret;
 397 }
 398 #endif
 399
 400 int setup_tests(void)
 401 {
 402 #ifdef OPENSSL_NO_EC
 403     TEST_note("Elliptic curves are disabled.");
 404 #else
 405     ADD_TEST(x9_62_tests);
 406     ADD_TEST(test_builtin);
 407 #endif
 408     return 1;
 409 }