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 /*
  12  * Low level APIs are deprecated for public use, but still ok for internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_EC is defined */
  17 #include "testutil.h"
  18
  19 #ifndef OPENSSL_NO_EC
  20
  21 # include <openssl/evp.h>
  22 # include <openssl/bn.h>
  23 # include <openssl/ec.h>
  24 # include <openssl/rand.h>
  25 # include "internal/nelem.h"
  26 # include "ecdsatest.h"
  27
  28 /* functions to change the RAND_METHOD */
  29 static int fbytes(unsigned char *buf, int num);
  30
  31 static RAND_METHOD fake_rand;
  32 static const RAND_METHOD *old_rand;
  33 static int use_fake = 0;
  34 static const char *numbers[2];
  35 static size_t crv_len = 0;
  36 static EC_builtin_curve *curves = NULL;
  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(unsigned char *buf, int num)
  61 {
  62     int ret = 0;
  63     static int fbytes_counter = 0;
  64     BIGNUM *tmp = NULL;
  65
  66     if (use_fake == 0)
  67         return old_rand->bytes(buf, num);
  68
  69     use_fake = 0;
  70
  71     if (!TEST_ptr(tmp = BN_new())
  72         || !TEST_int_lt(fbytes_counter, OSSL_NELEM(numbers))
  73         || !TEST_true(BN_hex2bn(&tmp, numbers[fbytes_counter]))
  74         /* tmp might need leading zeros so pad it out */
  75         || !TEST_int_le(BN_num_bytes(tmp), num)
  76         || !TEST_true(BN_bn2binpad(tmp, buf, num)))
  77         goto err;
  78
  79     fbytes_counter = (fbytes_counter + 1) % OSSL_NELEM(numbers);
  80     ret = 1;
  81  err:
  82     BN_free(tmp);
  83     return ret;
  84 }
  85
  86 /*-
  87  * This function hijacks the RNG to feed it the chosen ECDSA key and nonce.
  88  * The ECDSA KATs are from:
  89  * - the X9.62 draft (4)
  90  * - NIST CAVP (720)
  91  *
  92  * It uses the low-level ECDSA_sign_setup instead of EVP to control the RNG.
  93  * NB: This is not how applications should use ECDSA; this is only for testing.
  94  *
  95  * Tests the library can successfully:
  96  * - generate public keys that matches those KATs
  97  * - create ECDSA signatures that match those KATs
  98  * - accept those signatures as valid
  99  */
 100 static int x9_62_tests(int n)
 101 {
 102     int nid, md_nid, ret = 0;
 103     const char *r_in = NULL, *s_in = NULL, *tbs = NULL;
 104     unsigned char *pbuf = NULL, *qbuf = NULL, *message = NULL;
 105     unsigned char digest[EVP_MAX_MD_SIZE];
 106     unsigned int dgst_len = 0;
 107     long q_len, msg_len = 0;
 108     size_t p_len;
 109     EVP_MD_CTX *mctx = NULL;
 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 = NULL, *sig_s = NULL;
 115
 116     nid = ecdsa_cavs_kats[n].nid;
 117     md_nid = ecdsa_cavs_kats[n].md_nid;
 118     r_in = ecdsa_cavs_kats[n].r;
 119     s_in = ecdsa_cavs_kats[n].s;
 120     tbs = ecdsa_cavs_kats[n].msg;
 121     numbers[0] = ecdsa_cavs_kats[n].d;
 122     numbers[1] = ecdsa_cavs_kats[n].k;
 123
 124     TEST_info("ECDSA KATs for curve %s", OBJ_nid2sn(nid));
 125
 126 #ifdef FIPS_MODE
 127     if (EC_curve_nid2nist(nid) == NULL)
 128         return TEST_skip("skip non approved curves");
 129 #endif /* FIPS_MODE */
 130
 131     if (!TEST_ptr(mctx = EVP_MD_CTX_new())
 132         /* get the message digest */
 133         || !TEST_ptr(message = OPENSSL_hexstr2buf(tbs, &msg_len))
 134         || !TEST_true(EVP_DigestInit_ex(mctx, EVP_get_digestbynid(md_nid), NULL))
 135         || !TEST_true(EVP_DigestUpdate(mctx, message, msg_len))
 136         || !TEST_true(EVP_DigestFinal_ex(mctx, digest, &dgst_len))
 137         /* create the key */
 138         || !TEST_ptr(key = EC_KEY_new_by_curve_name(nid))
 139         /* load KAT variables */
 140         || !TEST_ptr(r = BN_new())
 141         || !TEST_ptr(s = BN_new())
 142         || !TEST_true(BN_hex2bn(&r, r_in))
 143         || !TEST_true(BN_hex2bn(&s, s_in))
 144         /* swap the RNG source */
 145         || !TEST_true(change_rand()))
 146         goto err;
 147
 148     /* public key must match KAT */
 149     use_fake = 1;
 150     if (!TEST_true(EC_KEY_generate_key(key))
 151         || !TEST_true(p_len = EC_KEY_key2buf(key, POINT_CONVERSION_UNCOMPRESSED,
 152                                              &pbuf, NULL))
 153         || !TEST_ptr(qbuf = OPENSSL_hexstr2buf(ecdsa_cavs_kats[n].Q, &q_len))
 154         || !TEST_int_eq(q_len, p_len)
 155         || !TEST_mem_eq(qbuf, q_len, pbuf, p_len))
 156         goto err;
 157
 158     /* create the signature via ECDSA_sign_setup to avoid use of ECDSA nonces */
 159     use_fake = 1;
 160     if (!TEST_true(ECDSA_sign_setup(key, NULL, &kinv, &rp))
 161         || !TEST_ptr(signature = ECDSA_do_sign_ex(digest, dgst_len,
 162                                                   kinv, rp, key))
 163         /* verify the signature */
 164         || !TEST_int_eq(ECDSA_do_verify(digest, dgst_len, signature, key), 1))
 165         goto err;
 166
 167     /* compare the created signature with the expected signature */
 168     ECDSA_SIG_get0(signature, &sig_r, &sig_s);
 169     if (!TEST_BN_eq(sig_r, r)
 170         || !TEST_BN_eq(sig_s, s))
 171         goto err;
 172
 173     ret = 1;
 174
 175  err:
 176     /* restore the RNG source */
 177     if (!TEST_true(restore_rand()))
 178         ret = 0;
 179
 180     OPENSSL_free(message);
 181     OPENSSL_free(pbuf);
 182     OPENSSL_free(qbuf);
 183     EC_KEY_free(key);
 184     ECDSA_SIG_free(signature);
 185     BN_free(r);
 186     BN_free(s);
 187     EVP_MD_CTX_free(mctx);
 188     BN_clear_free(kinv);
 189     BN_clear_free(rp);
 190     return ret;
 191 }
 192
 193 /*-
 194  * Positive and negative ECDSA testing through EVP interface:
 195  * - EVP_DigestSign (this is the one-shot version)
 196  * - EVP_DigestVerify
 197  *
 198  * Tests the library can successfully:
 199  * - create a key
 200  * - create a signature
 201  * - accept that signature
 202  * - reject that signature with a different public key
 203  * - reject that signature if its length is not correct
 204  * - reject that signature after modifying the message
 205  * - accept that signature after un-modifying the message
 206  * - reject that signature after modifying the signature
 207  * - accept that signature after un-modifying the signature
 208  */
 209 static int set_sm2_id(EVP_MD_CTX *mctx, EVP_PKEY *pkey)
 210 {
 211     /* With the SM2 key type, the SM2 ID is mandatory */
 212     static const char sm2_id[] = { 1, 2, 3, 4, 'l', 'e', 't', 't', 'e', 'r' };
 213     EVP_PKEY_CTX *pctx;
 214
 215     if (!TEST_ptr(pctx = EVP_MD_CTX_pkey_ctx(mctx))
 216         || !TEST_int_gt(EVP_PKEY_CTX_set1_id(pctx, sm2_id, sizeof(sm2_id)), 0))
 217         return 0;
 218     return 1;
 219 }
 220
 221 static int test_builtin(int n, int as)
 222 {
 223     EC_KEY *eckey_neg = NULL, *eckey = NULL;
 224     unsigned char dirt, offset, tbs[128];
 225     unsigned char *sig = NULL;
 226     EVP_PKEY *pkey_neg = NULL, *pkey = NULL;
 227     EVP_MD_CTX *mctx = NULL;
 228     size_t sig_len;
 229     int nid, ret = 0;
 230     int temp;
 231
 232     nid = curves[n].nid;
 233
 234     /* skip built-in curves where ord(G) is not prime */
 235     if (nid == NID_ipsec4 || nid == NID_ipsec3) {
 236         TEST_info("skipped: ECDSA unsupported for curve %s", OBJ_nid2sn(nid));
 237         return 1;
 238     }
 239
 240     TEST_info("testing ECDSA for curve %s as %s key type", OBJ_nid2sn(nid),
 241               as == EVP_PKEY_EC ? "EC" : "SM2");
 242
 243     if (!TEST_ptr(mctx = EVP_MD_CTX_new())
 244         /* get some random message data */
 245         || !TEST_true(RAND_bytes(tbs, sizeof(tbs)))
 246         /* real key */
 247         || !TEST_ptr(eckey = EC_KEY_new_by_curve_name(nid))
 248         || !TEST_true(EC_KEY_generate_key(eckey))
 249         || !TEST_ptr(pkey = EVP_PKEY_new())
 250         || !TEST_true(EVP_PKEY_assign_EC_KEY(pkey, eckey))
 251         /* fake key for negative testing */
 252         || !TEST_ptr(eckey_neg = EC_KEY_new_by_curve_name(nid))
 253         || !TEST_true(EC_KEY_generate_key(eckey_neg))
 254         || !TEST_ptr(pkey_neg = EVP_PKEY_new())
 255         || !TEST_true(EVP_PKEY_assign_EC_KEY(pkey_neg, eckey_neg)))
 256         goto err;
 257
 258     temp = ECDSA_size(eckey);
 259
 260     /*
 261      * |as| indicates how we want to treat the key, i.e. what sort of
 262      * computation we want to do with it.  The two choices are the key
 263      * types EVP_PKEY_EC and EVP_PKEY_SM2.  It's perfectly possible to
 264      * switch back and forth between those two key types, regardless of
 265      * curve, even though the default is to have EVP_PKEY_SM2 for the
 266      * SM2 curve and EVP_PKEY_EC for all other curves.
 267      */
 268     if (!TEST_true(EVP_PKEY_set_alias_type(pkey, as))
 269         || !TEST_true(EVP_PKEY_set_alias_type(pkey_neg, as)))
 270             goto err;
 271
 272     if (!TEST_int_ge(temp, 0)
 273         || !TEST_ptr(sig = OPENSSL_malloc(sig_len = (size_t)temp))
 274         /* create a signature */
 275         || !TEST_true(EVP_DigestSignInit(mctx, NULL, NULL, NULL, pkey))
 276         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 277         || !TEST_true(EVP_DigestSign(mctx, sig, &sig_len, tbs, sizeof(tbs)))
 278         || !TEST_int_le(sig_len, ECDSA_size(eckey))
 279         || !TEST_true(EVP_MD_CTX_reset(mctx))
 280         /* negative test, verify with wrong key, 0 return */
 281         || !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey_neg))
 282         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey_neg))
 283         || !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 0)
 284         || !TEST_true(EVP_MD_CTX_reset(mctx))
 285         /* negative test, verify with wrong signature length, -1 return */
 286         || !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
 287         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 288         || !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len - 1, tbs, sizeof(tbs)), -1)
 289         || !TEST_true(EVP_MD_CTX_reset(mctx))
 290         /* positive test, verify with correct key, 1 return */
 291         || !TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
 292         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 293         || !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1)
 294         || !TEST_true(EVP_MD_CTX_reset(mctx)))
 295         goto err;
 296
 297     /* muck with the message, test it fails with 0 return */
 298     tbs[0] ^= 1;
 299     if (!TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
 300         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 301         || !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 0)
 302         || !TEST_true(EVP_MD_CTX_reset(mctx)))
 303         goto err;
 304     /* un-muck and test it verifies */
 305     tbs[0] ^= 1;
 306     if (!TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
 307         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 308         || !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1)
 309         || !TEST_true(EVP_MD_CTX_reset(mctx)))
 310         goto err;
 311
 312     /*-
 313      * Muck with the ECDSA signature. The DER encoding is one of:
 314      * - 30 LL 02 ..
 315      * - 30 81 LL 02 ..
 316      *
 317      * - Sometimes this mucks with the high level DER sequence wrapper:
 318      *   in that case, DER-parsing of the whole signature should fail.
 319      *
 320      * - Sometimes this mucks with the DER-encoding of ECDSA.r:
 321      *   in that case, DER-parsing of ECDSA.r should fail.
 322      *
 323      * - Sometimes this mucks with the DER-encoding of ECDSA.s:
 324      *   in that case, DER-parsing of ECDSA.s should fail.
 325      *
 326      * - Sometimes this mucks with ECDSA.r:
 327      *   in that case, the signature verification should fail.
 328      *
 329      * - Sometimes this mucks with ECDSA.s:
 330      *   in that case, the signature verification should fail.
 331      *
 332      * The usual case is changing the integer value of ECDSA.r or ECDSA.s.
 333      * Because the ratio of DER overhead to signature bytes is small.
 334      * So most of the time it will be one of the last two cases.
 335      *
 336      * In any case, EVP_PKEY_verify should not return 1 for valid.
 337      */
 338     offset = tbs[0] % sig_len;
 339     dirt = tbs[1] ? tbs[1] : 1;
 340     sig[offset] ^= dirt;
 341     if (!TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
 342         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 343         || !TEST_int_ne(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1)
 344         || !TEST_true(EVP_MD_CTX_reset(mctx)))
 345         goto err;
 346     /* un-muck and test it verifies */
 347     sig[offset] ^= dirt;
 348     if (!TEST_true(EVP_DigestVerifyInit(mctx, NULL, NULL, NULL, pkey))
 349         || (as == EVP_PKEY_SM2 && !set_sm2_id(mctx, pkey))
 350         || !TEST_int_eq(EVP_DigestVerify(mctx, sig, sig_len, tbs, sizeof(tbs)), 1)
 351         || !TEST_true(EVP_MD_CTX_reset(mctx)))
 352         goto err;
 353
 354     ret = 1;
 355  err:
 356     EVP_PKEY_free(pkey);
 357     EVP_PKEY_free(pkey_neg);
 358     EVP_MD_CTX_free(mctx);
 359     OPENSSL_free(sig);
 360     return ret;
 361 }
 362
 363 static int test_builtin_as_ec(int n)
 364 {
 365     return test_builtin(n, EVP_PKEY_EC);
 366 }
 367
 368 # ifndef OPENSSL_NO_SM2
 369 static int test_builtin_as_sm2(int n)
 370 {
 371     return test_builtin(n, EVP_PKEY_SM2);
 372 }
 373 # endif
 374 #endif /* OPENSSL_NO_EC */
 375
 376 int setup_tests(void)
 377 {
 378 #ifdef OPENSSL_NO_EC
 379     TEST_note("Elliptic curves are disabled.");
 380 #else
 381     /* get a list of all internal curves */
 382     crv_len = EC_get_builtin_curves(NULL, 0);
 383     if (!TEST_ptr(curves = OPENSSL_malloc(sizeof(*curves) * crv_len))
 384         || !TEST_true(EC_get_builtin_curves(curves, crv_len)))
 385         return 0;
 386     ADD_ALL_TESTS(test_builtin_as_ec, crv_len);
 387 # ifndef OPENSSL_NO_SM2
 388     ADD_ALL_TESTS(test_builtin_as_sm2, crv_len);
 389 # endif
 390     ADD_ALL_TESTS(x9_62_tests, OSSL_NELEM(ecdsa_cavs_kats));
 391 #endif
 392     return 1;
 393 }
 394
 395 void cleanup_tests(void)
 396 {
 397 #ifndef OPENSSL_NO_EC
 398     OPENSSL_free(curves);
 399 #endif
 400 }