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