test/ecdsatest.c

   1 /*
   2  * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
   4  *
   5  * Licensed under the OpenSSL license (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
  17 #ifndef OPENSSL_NO_EC
  18
  19 # include <openssl/crypto.h>
  20 # include <openssl/bio.h>
  21 # include <openssl/evp.h>
  22 # include <openssl/bn.h>
  23 # include <openssl/ec.h>
  24 # ifndef OPENSSL_NO_ENGINE
  25 #  include <openssl/engine.h>
  26 # endif
  27 # include <openssl/err.h>
  28 # include <openssl/rand.h>
  29 # include "testutil.h"
  30
  31 static const char rnd_seed[] = "string to make the random number generator "
  32     "think it has entropy";
  33
  34
  35 /* functions to change the RAND_METHOD */
  36 static int fbytes(unsigned char *buf, int num);
  37
  38 static RAND_METHOD fake_rand;
  39 static const RAND_METHOD *old_rand;
  40
  41 static int change_rand(void)
  42 {
  43     /* save old rand method */
  44     if (!TEST_ptr(old_rand = RAND_get_rand_method()))
  45         return 0;
  46
  47     fake_rand = *old_rand;
  48     /* use own random function */
  49     fake_rand.bytes = fbytes;
  50     /* set new RAND_METHOD */
  51     if (!TEST_true(RAND_set_rand_method(&fake_rand)))
  52         return 0;
  53     return 1;
  54 }
  55
  56 static int restore_rand(void)
  57 {
  58     if (!TEST_true(RAND_set_rand_method(old_rand)))
  59         return 0;
  60     return 1;
  61 }
  62
  63 static int fbytes_counter = 0, use_fake = 0;
  64 static const char *numbers[8] = {
  65     "651056770906015076056810763456358567190100156695615665659",
  66     "6140507067065001063065065565667405560006161556565665656654",
  67     "8763001015071075675010661307616710783570106710677817767166"
  68         "71676178726717",
  69     "7000000175690566466555057817571571075705015757757057795755"
  70         "55657156756655",
  71     "1275552191113212300012030439187146164646146646466749494799",
  72     "1542725565216523985789236956265265265235675811949404040041",
  73     "1456427555219115346513212300075341203043918714616464614664"
  74         "64667494947990",
  75     "1712787255652165239672857892369562652652652356758119494040"
  76         "40041670216363"
  77 };
  78
  79 static int fbytes(unsigned char *buf, int num)
  80 {
  81     int ret = 0;
  82     BIGNUM *tmp = NULL;
  83
  84     if (use_fake == 0)
  85         return old_rand->bytes(buf, num);
  86
  87     use_fake = 0;
  88
  89     if (fbytes_counter >= 8)
  90         return 0;
  91     if (!TEST_ptr(tmp = BN_new()))
  92         return 0;
  93     if (!TEST_true(BN_dec2bn(&tmp, numbers[fbytes_counter]))) {
  94         BN_free(tmp);
  95         return 0;
  96     }
  97     fbytes_counter++;
  98     if (TEST_int_eq(BN_num_bytes(tmp), num)
  99             && TEST_true(BN_bn2bin(tmp, buf)))
 100         ret = 1;
 101     BN_free(tmp);
 102     return ret;
 103 }
 104
 105 /* some tests from the X9.62 draft */
 106 static int x9_62_test_internal(int nid, const char *r_in, const char *s_in)
 107 {
 108     int ret = 0;
 109     const char message[] = "abc";
 110     unsigned char digest[20];
 111     unsigned int dgst_len = 0;
 112     EVP_MD_CTX *md_ctx;
 113     EC_KEY *key = NULL;
 114     ECDSA_SIG *signature = NULL;
 115     BIGNUM *r = NULL, *s = NULL;
 116     BIGNUM *kinv = NULL, *rp = NULL;
 117     const BIGNUM *sig_r, *sig_s;
 118
 119     if (!TEST_ptr(md_ctx = EVP_MD_CTX_new()))
 120         goto x962_int_err;
 121
 122     /* get the message digest */
 123     if (!TEST_true(EVP_DigestInit(md_ctx, EVP_sha1()))
 124         || !TEST_true(EVP_DigestUpdate(md_ctx, (const void *)message, 3))
 125         || !TEST_true(EVP_DigestFinal(md_ctx, digest, &dgst_len)))
 126         goto x962_int_err;
 127
 128     TEST_info("testing %s", OBJ_nid2sn(nid));
 129
 130     /* create the key */
 131     if (!TEST_ptr(key = EC_KEY_new_by_curve_name(nid)))
 132         goto x962_int_err;
 133     use_fake = 1;
 134     if (!TEST_true(EC_KEY_generate_key(key)))
 135         goto x962_int_err;
 136
 137     /* create the signature */
 138     use_fake = 1;
 139     /* Use ECDSA_sign_setup to avoid use of ECDSA nonces */
 140     if (!TEST_true(ECDSA_sign_setup(key, NULL, &kinv, &rp)))
 141         goto x962_int_err;
 142     if (!TEST_ptr(signature = ECDSA_do_sign_ex(digest, 20, kinv, rp, key)))
 143         goto x962_int_err;
 144
 145     /* compare the created signature with the expected signature */
 146     if (!TEST_ptr(r = BN_new()) || !TEST_ptr(s = BN_new()))
 147         goto x962_int_err;
 148     if (!TEST_true(BN_dec2bn(&r, r_in)) || !TEST_true(BN_dec2bn(&s, s_in)))
 149         goto x962_int_err;
 150     ECDSA_SIG_get0(signature, &sig_r, &sig_s);
 151     if (!TEST_BN_eq(sig_r, r)
 152             || !TEST_BN_eq(sig_s, s))
 153         goto x962_int_err;
 154
 155     /* verify the signature */
 156     if (!TEST_int_eq(ECDSA_do_verify(digest, 20, signature, key), 1))
 157         goto x962_int_err;
 158
 159     ret = 1;
 160
 161  x962_int_err:
 162     EC_KEY_free(key);
 163     ECDSA_SIG_free(signature);
 164     BN_free(r);
 165     BN_free(s);
 166     EVP_MD_CTX_free(md_ctx);
 167     BN_clear_free(kinv);
 168     BN_clear_free(rp);
 169     return ret;
 170 }
 171
 172 static int x9_62_tests()
 173 {
 174     int ret = 0;
 175
 176     /* set own rand method */
 177     if (!change_rand())
 178         goto x962_err;
 179
 180     if (!TEST_true(x9_62_test_internal(NID_X9_62_prime192v1,
 181                  "3342403536405981729393488334694600415596881826869351677613",
 182                  "5735822328888155254683894997897571951568553642892029982342")))
 183         goto x962_err;
 184     if (!TEST_true(x9_62_test_internal(NID_X9_62_prime239v1,
 185                  "3086361431751678114926225473006680188549593787585317781474"
 186                              "62058306432176",
 187                  "3238135532097973577080787768312505059318910517550078427819"
 188                              "78505179448783")))
 189         goto x962_err;
 190
 191 # ifndef OPENSSL_NO_EC2M
 192     if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb191v1,
 193                  "87194383164871543355722284926904419997237591535066528048",
 194                  "308992691965804947361541664549085895292153777025772063598")))
 195         goto x962_err;
 196     if (!TEST_true(x9_62_test_internal(NID_X9_62_c2tnb239v1,
 197                  "2159633321041961198501834003903461262881815148684178964245"
 198                              "5876922391552",
 199                  "1970303740007316867383349976549972270528498040721988191026"
 200                              "49413465737174")))
 201         goto x962_err;
 202 # endif
 203     ret = 1;
 204
 205  x962_err:
 206     if (!TEST_true(restore_rand()))
 207         ret = 0;
 208     return ret;
 209 }
 210
 211 static int test_builtin(void)
 212 {
 213     EC_builtin_curve *curves = NULL;
 214     size_t crv_len = 0, n = 0;
 215     EC_KEY *eckey = NULL, *wrong_eckey = NULL;
 216     EC_GROUP *group;
 217     ECDSA_SIG *ecdsa_sig = NULL, *modified_sig = NULL;
 218     unsigned char digest[20], wrong_digest[20];
 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, 20))
 231             || !TEST_true(RAND_bytes(wrong_digest, 20)))
 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_X25519)
 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         if (degree < 160) {
 256             /* drop the curve */
 257             EC_KEY_free(eckey);
 258             eckey = NULL;
 259             continue;
 260         }
 261         TEST_info("testing %s", OBJ_nid2sn(nid));
 262
 263         /* create key */
 264         if (!TEST_true(EC_KEY_generate_key(eckey)))
 265             goto builtin_err;
 266         /* create second key */
 267         if (!TEST_ptr(wrong_eckey = EC_KEY_new())
 268                 || !TEST_ptr(group = EC_GROUP_new_by_curve_name(nid))
 269                 || !TEST_true(EC_KEY_set_group(wrong_eckey, group)))
 270             goto builtin_err;
 271         EC_GROUP_free(group);
 272         if (!TEST_true(EC_KEY_generate_key(wrong_eckey)))
 273             goto builtin_err;
 274
 275         /* check key */
 276         if (!TEST_true(EC_KEY_check_key(eckey)))
 277             goto builtin_err;
 278
 279         /* create signature */
 280         sig_len = ECDSA_size(eckey);
 281         if (!TEST_ptr(signature = OPENSSL_malloc(sig_len))
 282                 || !TEST_true(ECDSA_sign(0, digest, 20, signature, &sig_len,
 283                                          eckey)))
 284             goto builtin_err;
 285
 286         /* verify signature */
 287         if (!TEST_int_eq(ECDSA_verify(0, digest, 20, signature, sig_len,
 288                                       eckey), 1))
 289             goto builtin_err;
 290
 291         /* verify signature with the wrong key */
 292         if (!TEST_int_ne(ECDSA_verify(0, digest, 20, signature, sig_len,
 293                                       wrong_eckey), 1))
 294             goto builtin_err;
 295
 296         /* wrong digest */
 297         if (!TEST_int_ne(ECDSA_verify(0, wrong_digest, 20, signature,
 298                                       sig_len, eckey), 1))
 299             goto builtin_err;
 300
 301         /* wrong length */
 302         if (!TEST_int_ne(ECDSA_verify(0, digest, 20, signature,
 303                                       sig_len - 1, eckey), 1))
 304             goto builtin_err;
 305
 306         /*
 307          * Modify a single byte of the signature: to ensure we don't garble
 308          * the ASN1 structure, we read the raw signature and modify a byte in
 309          * one of the bignums directly.
 310          */
 311         sig_ptr = signature;
 312         if (!TEST_ptr(ecdsa_sig = d2i_ECDSA_SIG(NULL, &sig_ptr, sig_len)))
 313             goto builtin_err;
 314
 315         ECDSA_SIG_get0(ecdsa_sig, &sig_r, &sig_s);
 316
 317         /* Store the two BIGNUMs in raw_buf. */
 318         r_len = BN_num_bytes(sig_r);
 319         s_len = BN_num_bytes(sig_s);
 320         bn_len = (degree + 7) / 8;
 321         if (!TEST_false(r_len > bn_len)
 322                 || !TEST_false(s_len > bn_len))
 323             goto builtin_err;
 324         buf_len = 2 * bn_len;
 325         if (!TEST_ptr(raw_buf = OPENSSL_zalloc(buf_len)))
 326             goto builtin_err;
 327         BN_bn2bin(sig_r, raw_buf + bn_len - r_len);
 328         BN_bn2bin(sig_s, raw_buf + buf_len - s_len);
 329
 330         /* Modify a single byte in the buffer. */
 331         offset = raw_buf[10] % buf_len;
 332         dirt = raw_buf[11] ? raw_buf[11] : 1;
 333         raw_buf[offset] ^= dirt;
 334
 335         /* Now read the BIGNUMs back in from raw_buf. */
 336         if (!TEST_ptr(modified_sig = ECDSA_SIG_new()))
 337             goto builtin_err;
 338         if (!TEST_ptr(modified_r = BN_bin2bn(raw_buf, bn_len, NULL))
 339                 || !TEST_ptr(modified_s = BN_bin2bn(raw_buf + bn_len,
 340                                                     bn_len, NULL))
 341                 || !TEST_true(ECDSA_SIG_set0(modified_sig,
 342                                              modified_r, modified_s))) {
 343             BN_free(modified_r);
 344             BN_free(modified_s);
 345             goto builtin_err;
 346         }
 347         sig_ptr2 = signature;
 348         sig_len = i2d_ECDSA_SIG(modified_sig, &sig_ptr2);
 349         if (!TEST_false(ECDSA_verify(0, digest, 20, 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, 20, signature, sig_len, eckey)))
 367             goto builtin_err;
 368
 369         /* cleanup */
 370         ERR_clear_error();
 371         OPENSSL_free(signature);
 372         signature = NULL;
 373         EC_KEY_free(eckey);
 374         eckey = NULL;
 375         EC_KEY_free(wrong_eckey);
 376         wrong_eckey = NULL;
 377         ECDSA_SIG_free(ecdsa_sig);
 378         ecdsa_sig = NULL;
 379         ECDSA_SIG_free(modified_sig);
 380         modified_sig = NULL;
 381         OPENSSL_free(raw_buf);
 382         raw_buf = NULL;
 383     }
 384
 385     ret = 1;
 386  builtin_err:
 387     EC_KEY_free(eckey);
 388     EC_KEY_free(wrong_eckey);
 389     ECDSA_SIG_free(ecdsa_sig);
 390     ECDSA_SIG_free(modified_sig);
 391     OPENSSL_free(signature);
 392     OPENSSL_free(raw_buf);
 393     OPENSSL_free(curves);
 394
 395     return ret;
 396 }
 397
 398 void register_tests(void)
 399 {
 400 #ifdef OPENSSL_NO_EC
 401     TEST_note("Elliptic curves are disabled.");
 402 #else
 403     /* initialize the prng */
 404     RAND_seed(rnd_seed, sizeof(rnd_seed));
 405     ADD_TEST(x9_62_tests);
 406     ADD_TEST(test_builtin);
 407 #endif
 408 }
 409 #endif