test/ecdsatest.c

   1 /*
   2  * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /* ====================================================================
  11  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  12  *
  13  * Portions of the attached software ("Contribution") are developed by
  14  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
  15  *
  16  * The Contribution is licensed pursuant to the OpenSSL open source
  17  * license provided above.
  18  *
  19  * The elliptic curve binary polynomial software is originally written by
  20  * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems Laboratories.
  21  *
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_EC is defined */
  29
  30 #ifdef OPENSSL_NO_EC
  31 int main(int argc, char *argv[])
  32 {
  33     puts("Elliptic curves are disabled.");
  34     return 0;
  35 }
  36 #else
  37
  38 # include <openssl/crypto.h>
  39 # include <openssl/bio.h>
  40 # include <openssl/evp.h>
  41 # include <openssl/bn.h>
  42 # include <openssl/ec.h>
  43 # ifndef OPENSSL_NO_ENGINE
  44 #  include <openssl/engine.h>
  45 # endif
  46 # include <openssl/err.h>
  47 # include <openssl/rand.h>
  48 # include "testutil.h"
  49
  50 static const char rnd_seed[] = "string to make the random number generator "
  51     "think it has entropy";
  52
  53
  54 /* functions to change the RAND_METHOD */
  55 static int fbytes(unsigned char *buf, int num);
  56
  57 static RAND_METHOD fake_rand;
  58 static const RAND_METHOD *old_rand;
  59
  60 static int change_rand(void)
  61 {
  62     /* save old rand method */
  63     if (!TEST_ptr(old_rand = RAND_get_rand_method()))
  64         return 0;
  65
  66     fake_rand = *old_rand;
  67     /* use own random function */
  68     fake_rand.bytes = fbytes;
  69     /* set new RAND_METHOD */
  70     if (!TEST_true(RAND_set_rand_method(&fake_rand)))
  71         return 0;
  72     return 1;
  73 }
  74
  75 static int restore_rand(void)
  76 {
  77     if (!TEST_true(RAND_set_rand_method(old_rand)))
  78         return 0;
  79     return 1;
  80 }
  81
  82 static int fbytes_counter = 0, use_fake = 0;
  83 static const char *numbers[8] = {
  84     "651056770906015076056810763456358567190100156695615665659",
  85     "6140507067065001063065065565667405560006161556565665656654",
  86     "8763001015071075675010661307616710783570106710677817767166"
  87         "71676178726717",
  88     "7000000175690566466555057817571571075705015757757057795755"
  89         "55657156756655",
  90     "1275552191113212300012030439187146164646146646466749494799",
  91     "1542725565216523985789236956265265265235675811949404040041",
  92     "1456427555219115346513212300075341203043918714616464614664"
  93         "64667494947990",
  94     "1712787255652165239672857892369562652652652356758119494040"
  95         "40041670216363"
  96 };
  97
  98 static int fbytes(unsigned char *buf, int num)
  99 {
 100     int ret = 0;
 101     BIGNUM *tmp = NULL;
 102
 103     if (use_fake == 0)
 104         return old_rand->bytes(buf, num);
 105
 106     use_fake = 0;
 107
 108     if (fbytes_counter >= 8)
 109         return 0;
 110     if (!TEST_ptr(tmp = BN_new()))
 111         return 0;
 112     if (!TEST_true(BN_dec2bn(&tmp, numbers[fbytes_counter]))) {
 113         BN_free(tmp);
 114         return 0;
 115     }
 116     fbytes_counter++;
 117     if (TEST_int_eq(BN_num_bytes(tmp), num)
 118             && TEST_true(BN_bn2bin(tmp, buf)))
 119         ret = 1;
 120     BN_free(tmp);
 121     return ret;
 122 }
 123
 124 /* some tests from the X9.62 draft */
 125 static int x9_62_test_internal(int nid, const char *r_in, const char *s_in)
 126 {
 127     int ret = 0;
 128     const char message[] = "abc";
 129     unsigned char digest[20];
 130     unsigned int dgst_len = 0;
 131     EVP_MD_CTX *md_ctx;
 132     EC_KEY *key = NULL;
 133     ECDSA_SIG *signature = NULL;
 134     BIGNUM *r = NULL, *s = NULL;
 135     BIGNUM *kinv = NULL, *rp = NULL;
 136     const BIGNUM *sig_r, *sig_s;
 137
 138     if (!TEST_ptr(md_ctx = EVP_MD_CTX_new()))
 139         goto x962_int_err;
 140
 141     /* get the message digest */
 142     if (!TEST_true(EVP_DigestInit(md_ctx, EVP_sha1()))
 143         || !TEST_true(EVP_DigestUpdate(md_ctx, (const void *)message, 3))
 144         || !TEST_true(EVP_DigestFinal(md_ctx, digest, &dgst_len)))
 145         goto x962_int_err;
 146
 147     TEST_info("testing %s", OBJ_nid2sn(nid));
 148
 149     /* create the key */
 150     if (!TEST_ptr(key = EC_KEY_new_by_curve_name(nid)))
 151         goto x962_int_err;
 152     use_fake = 1;
 153     if (!TEST_true(EC_KEY_generate_key(key)))
 154         goto x962_int_err;
 155
 156     /* create the signature */
 157     use_fake = 1;
 158     /* Use ECDSA_sign_setup to avoid use of ECDSA nonces */
 159     if (!TEST_true(ECDSA_sign_setup(key, NULL, &kinv, &rp)))
 160         goto x962_int_err;
 161     if (!TEST_ptr(signature = ECDSA_do_sign_ex(digest, 20, kinv, rp, key)))
 162         goto x962_int_err;
 163
 164     /* compare the created signature with the expected signature */
 165     if (!TEST_ptr(r = BN_new()) || !TEST_ptr(s = BN_new()))
 166         goto x962_int_err;
 167     if (!TEST_true(BN_dec2bn(&r, r_in)) || !TEST_true(BN_dec2bn(&s, s_in)))
 168         goto x962_int_err;
 169     ECDSA_SIG_get0(signature, &sig_r, &sig_s);
 170     if (!TEST_int_eq(BN_cmp(sig_r, r), 0)
 171             || !TEST_int_eq(BN_cmp(sig_s, s), 0))
 172         goto x962_int_err;
 173
 174     /* verify the signature */
 175     if (!TEST_int_eq(ECDSA_do_verify(digest, 20, signature, key), 1))
 176         goto x962_int_err;
 177
 178     ret = 1;
 179
 180  x962_int_err:
 181     EC_KEY_free(key);
 182     ECDSA_SIG_free(signature);
 183     BN_free(r);
 184     BN_free(s);
 185     EVP_MD_CTX_free(md_ctx);
 186     BN_clear_free(kinv);
 187     BN_clear_free(rp);
 188     return ret;
 189 }
 190
 191 static int x9_62_tests()
 192 {
 193     int ret = 0;
 194
 195     /* set own rand method */
 196     if (!change_rand())
 197         goto x962_err;
 198
 199     if (!TEST_true(x9_62_test_internal(NID_X9_62_prime192v1,
 200                  "3342403536405981729393488334694600415596881826869351677613",
 201                  "5735822328888155254683894997897571951568553642892029982342")))
 202         goto x962_err;
 203     if (!TEST_true(x9_62_test_internal(NID_X9_62_prime239v1,
 204                  "3086361431751678114926225473006680188549593787585317781474"
 205                              "62058306432176",
 206                  "3238135532097973577080787768312505059318910517550078427819"
 207                              "78505179448783")))
 208         goto x962_err;
 209
 210 # ifndef OPENSSL_NO_EC2M
 211     if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb191v1,
 212                  "87194383164871543355722284926904419997237591535066528048",
 213                  "308992691965804947361541664549085895292153777025772063598")))
 214         goto x962_err;
 215     if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb239v1,
 216                  "2159633321041961198501834003903461262881815148684178964245"
 217                              "5876922391552",
 218                  "1970303740007316867383349976549972270528498040721988191026"
 219                              "49413465737174")))
 220         goto x962_err;
 221 # endif
 222     ret = 1;
 223
 224  x962_err:
 225     if (!TEST_true(restore_rand()))
 226         ret = 0;
 227     return ret;
 228 }
 229
 230 static int test_builtin(void)
 231 {
 232     EC_builtin_curve *curves = NULL;
 233     size_t crv_len = 0, n = 0;
 234     EC_KEY *eckey = NULL, *wrong_eckey = NULL;
 235     EC_GROUP *group;
 236     ECDSA_SIG *ecdsa_sig = NULL, *modified_sig = NULL;
 237     unsigned char digest[20], wrong_digest[20];
 238     unsigned char *signature = NULL;
 239     const unsigned char *sig_ptr;
 240     unsigned char *sig_ptr2;
 241     unsigned char *raw_buf = NULL;
 242     const BIGNUM *sig_r, *sig_s;
 243     BIGNUM *modified_r = NULL, *modified_s = NULL;
 244     BIGNUM *unmodified_r = NULL, *unmodified_s = NULL;
 245     unsigned int sig_len, degree, r_len, s_len, bn_len, buf_len;
 246     int nid, ret = 0;
 247
 248     /* fill digest values with some random data */
 249     if (!TEST_true(RAND_bytes(digest, 20))
 250             || !TEST_true(RAND_bytes(wrong_digest, 20)))
 251         goto builtin_err;
 252
 253     /* create and verify a ecdsa signature with every available curve */
 254     /* get a list of all internal curves */
 255     crv_len = EC_get_builtin_curves(NULL, 0);
 256     if (!TEST_ptr(curves = OPENSSL_malloc(sizeof(*curves) * crv_len))
 257             || !TEST_true(EC_get_builtin_curves(curves, crv_len)))
 258         goto builtin_err;
 259
 260     /* now create and verify a signature for every curve */
 261     for (n = 0; n < crv_len; n++) {
 262         unsigned char dirt, offset;
 263
 264         nid = curves[n].nid;
 265         if (nid == NID_ipsec4 || nid == NID_X25519)
 266             continue;
 267         /* create new ecdsa key (== EC_KEY) */
 268         if (!TEST_ptr(eckey = EC_KEY_new())
 269                 || !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
 270                 || !TEST_true(EC_KEY_set_group(eckey, group)))
 271             goto builtin_err;
 272         EC_GROUP_free(group);
 273         degree = EC_GROUP_get_degree(EC_KEY_get0_group(eckey));
 274         if (degree < 160) {
 275             /* drop the curve */
 276             EC_KEY_free(eckey);
 277             eckey = NULL;
 278             continue;
 279         }
 280         TEST_info("testing %s", OBJ_nid2sn(nid));
 281
 282         /* create key */
 283         if (!TEST_true(EC_KEY_generate_key(eckey)))
 284             goto builtin_err;
 285         /* create second key */
 286         if (!TEST_ptr(wrong_eckey = EC_KEY_new())
 287                 || !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
 288                 || !TEST_true(EC_KEY_set_group(wrong_eckey, group)))
 289             goto builtin_err;
 290         EC_GROUP_free(group);
 291         if (!TEST_true(EC_KEY_generate_key(wrong_eckey)))
 292             goto builtin_err;
 293
 294         /* check key */
 295         if (!TEST_true(EC_KEY_check_key(eckey)))
 296             goto builtin_err;
 297
 298         /* create signature */
 299         sig_len = ECDSA_size(eckey);
 300         if (!TEST_ptr(signature = OPENSSL_malloc(sig_len))
 301                 || !TEST_true(ECDSA_sign(0, digest, 20, signature, &sig_len,
 302                                          eckey)))
 303             goto builtin_err;
 304
 305         /* verify signature */
 306         if (!TEST_int_eq(ECDSA_verify(0, digest, 20, signature, sig_len,
 307                                       eckey), 1))
 308             goto builtin_err;
 309
 310         /* verify signature with the wrong key */
 311         if (!TEST_int_ne(ECDSA_verify(0, digest, 20, signature, sig_len,
 312                                       wrong_eckey), 1))
 313             goto builtin_err;
 314
 315         /* wrong digest */
 316         if (!TEST_int_ne(ECDSA_verify(0, wrong_digest, 20, signature,
 317                                       sig_len, eckey), 1))
 318             goto builtin_err;
 319
 320         /* wrong length */
 321         if (!TEST_int_ne(ECDSA_verify(0, digest, 20, signature,
 322                                       sig_len - 1, eckey), 1))
 323             goto builtin_err;
 324
 325         /*
 326          * Modify a single byte of the signature: to ensure we don't garble
 327          * the ASN1 structure, we read the raw signature and modify a byte in
 328          * one of the bignums directly.
 329          */
 330         sig_ptr = signature;
 331         if (!TEST_ptr(ecdsa_sig = d2i_ECDSA_SIG(NULL, &sig_ptr, sig_len)))
 332             goto builtin_err;
 333
 334         ECDSA_SIG_get0(ecdsa_sig, &sig_r, &sig_s);
 335
 336         /* Store the two BIGNUMs in raw_buf. */
 337         r_len = BN_num_bytes(sig_r);
 338         s_len = BN_num_bytes(sig_s);
 339         bn_len = (degree + 7) / 8;
 340         if (!TEST_false(r_len > bn_len)
 341                 || !TEST_false(s_len > bn_len))
 342             goto builtin_err;
 343         buf_len = 2 * bn_len;
 344         if (!TEST_ptr(raw_buf = OPENSSL_zalloc(buf_len)))
 345             goto builtin_err;
 346         BN_bn2bin(sig_r, raw_buf + bn_len - r_len);
 347         BN_bn2bin(sig_s, raw_buf + buf_len - s_len);
 348
 349         /* Modify a single byte in the buffer. */
 350         offset = raw_buf[10] % buf_len;
 351         dirt = raw_buf[11] ? raw_buf[11] : 1;
 352         raw_buf[offset] ^= dirt;
 353
 354         /* Now read the BIGNUMs back in from raw_buf. */
 355         if (!TEST_ptr(modified_sig = ECDSA_SIG_new()))
 356             goto builtin_err;
 357         if (!TEST_ptr(modified_r = BN_bin2bn(raw_buf, bn_len, NULL))
 358                 || !TEST_ptr(modified_s = BN_bin2bn(raw_buf + bn_len,
 359                                                     bn_len, NULL))
 360                 || !TEST_true(ECDSA_SIG_set0(modified_sig,
 361                                              modified_r, modified_s))) {
 362             BN_free(modified_r);
 363             BN_free(modified_s);
 364             goto builtin_err;
 365         }
 366         sig_ptr2 = signature;
 367         sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
 368         if (!TEST_false(ECDSA_verify(0, digest, 20, signature, sig_len, eckey)))
 369             goto builtin_err;
 370
 371         /* Sanity check: undo the modification and verify signature. */
 372         raw_buf[offset] ^= dirt;
 373         if (!TEST_ptr(unmodified_r = BN_bin2bn(raw_buf, bn_len, NULL))
 374                 || !TEST_ptr(unmodified_s = BN_bin2bn(raw_buf + bn_len,
 375                                                        bn_len, NULL))
 376                 || !TEST_true(ECDSA_SIG_set0(modified_sig, unmodified_r,
 377                                              unmodified_s))) {
 378             BN_free(unmodified_r);
 379             BN_free(unmodified_s);
 380             goto builtin_err;
 381         }
 382
 383         sig_ptr2 = signature;
 384         sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
 385         if (!TEST_true(ECDSA_verify(0, digest, 20, signature, sig_len, eckey)))
 386             goto builtin_err;
 387
 388         /* cleanup */
 389         ERR_clear_error();
 390         OPENSSL_free(signature);
 391         signature = NULL;
 392         EC_KEY_free(eckey);
 393         eckey = NULL;
 394         EC_KEY_free(wrong_eckey);
 395         wrong_eckey = NULL;
 396         ECDSA_SIG_free(ecdsa_sig);
 397         ecdsa_sig = NULL;
 398         ECDSA_SIG_free(modified_sig);
 399         modified_sig = NULL;
 400         OPENSSL_free(raw_buf);
 401         raw_buf = NULL;
 402     }
 403
 404     ret = 1;
 405  builtin_err:
 406     EC_KEY_free(eckey);
 407     EC_KEY_free(wrong_eckey);
 408     ECDSA_SIG_free(ecdsa_sig);
 409     ECDSA_SIG_free(modified_sig);
 410     OPENSSL_free(signature);
 411     OPENSSL_free(raw_buf);
 412     OPENSSL_free(curves);
 413
 414     return ret;
 415 }
 416
 417 void register_tests(void)
 418 {
 419     /* initialize the prng */
 420     RAND_seed(rnd_seed, sizeof(rnd_seed));
 421     ADD_TEST(x9_62_tests);
 422     ADD_TEST(test_builtin);
 423 }
 424 #endif