test/drbgtest.c

   1 /*
   2  * Copyright 2011-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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  * RAND_DRBG_set is deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <string.h>
  17 #include "internal/nelem.h"
  18 #include <openssl/crypto.h>
  19 #include <openssl/err.h>
  20 #include <openssl/rand.h>
  21 #include <openssl/obj_mac.h>
  22 #include <openssl/evp.h>
  23 #include <openssl/aes.h>
  24 #include "../crypto/rand/rand_local.h"
  25 #include "../include/crypto/rand.h"
  26 #include "../providers/implementations/rands/drbg_local.h"
  27 #include "../crypto/evp/evp_local.h"
  28
  29 #if defined(_WIN32)
  30 # include <windows.h>
  31 #endif
  32
  33
  34 #if defined(OPENSSL_SYS_UNIX)
  35 # include <sys/types.h>
  36 # include <sys/wait.h>
  37 # include <unistd.h>
  38 #endif
  39
  40 #include "testutil.h"
  41 #include "drbgtest.h"
  42
  43 /*
  44  * DRBG generate wrappers
  45  */
  46 static int gen_bytes(EVP_RAND_CTX *drbg, unsigned char *buf, int num)
  47 {
  48     const RAND_METHOD *meth = RAND_get_rand_method();
  49
  50     if (meth != NULL && meth != RAND_OpenSSL()) {
  51         if (meth->bytes != NULL)
  52             return meth->bytes(buf, num);
  53         return -1;
  54     }
  55
  56     if (drbg != NULL)
  57         return EVP_RAND_generate(drbg, buf, num, 0, 0, NULL, 0);
  58     return 0;
  59 }
  60
  61 static int rand_bytes(unsigned char *buf, int num)
  62 {
  63     return gen_bytes(RAND_get0_public(NULL), buf, num);
  64 }
  65
  66 static int rand_priv_bytes(unsigned char *buf, int num)
  67 {
  68     return gen_bytes(RAND_get0_private(NULL), buf, num);
  69 }
  70
  71 /*
  72  * DRBG query functions
  73  */
  74 static int state(EVP_RAND_CTX *drbg)
  75 {
  76     return EVP_RAND_state(drbg);
  77 }
  78
  79 static unsigned int query_rand_uint(EVP_RAND_CTX *drbg, const char *name)
  80 {
  81     OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
  82     unsigned int n;
  83
  84     *params = OSSL_PARAM_construct_uint(name, &n);
  85     if (EVP_RAND_get_ctx_params(drbg, params))
  86         return n;
  87     return 0;
  88 }
  89
  90 #define DRBG_UINT(name)                                 \
  91     static unsigned int name(EVP_RAND_CTX *drbg)        \
  92     {                                                   \
  93         return query_rand_uint(drbg, #name);            \
  94     }
  95 DRBG_UINT(reseed_counter)
  96
  97 static PROV_DRBG *prov_rand(EVP_RAND_CTX *drbg)
  98 {
  99     return (PROV_DRBG *)drbg->data;
 100 }
 101
 102 static void set_reseed_counter(EVP_RAND_CTX *drbg, unsigned int n)
 103 {
 104     PROV_DRBG *p = prov_rand(drbg);
 105
 106     p->reseed_counter = n;
 107 }
 108
 109 static void inc_reseed_counter(EVP_RAND_CTX *drbg)
 110 {
 111     set_reseed_counter(drbg, reseed_counter(drbg) + 1);
 112 }
 113
 114 static time_t reseed_time(EVP_RAND_CTX *drbg)
 115 {
 116     OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
 117     time_t t;
 118
 119     *params = OSSL_PARAM_construct_time_t(OSSL_DRBG_PARAM_RESEED_TIME, &t);
 120     if (EVP_RAND_get_ctx_params(drbg, params))
 121         return t;
 122     return 0;
 123 }
 124
 125 /*
 126  * When building the FIPS module, it isn't possible to disable the continuous
 127  * RNG tests.  Tests that require this are skipped.
 128  */
 129 static int crngt_skip(void)
 130 {
 131 #ifdef FIPS_MODULE
 132     return 1;
 133 #else
 134     return 0;
 135 #endif
 136 }
 137
 138  /*
 139  * Disable CRNG testing if it is enabled.
 140  * This stub remains to indicate the calling locations where it is necessary.
 141  * Once the RNG infrastructure is able to disable these tests, it should be
 142  * reconstituted.
 143  */
 144 static int disable_crngt(EVP_RAND_CTX *drbg)
 145 {
 146     return 1;
 147 }
 148
 149 /*
 150  * Generates random output using rand_bytes() and rand_priv_bytes()
 151  * and checks whether the three shared DRBGs were reseeded as
 152  * expected.
 153  *
 154  * |expect_success|: expected outcome (as reported by RAND_status())
 155  * |primary|, |public|, |private|: pointers to the three shared DRBGs
 156  * |expect_xxx_reseed| =
 157  *       1:  it is expected that the specified DRBG is reseeded
 158  *       0:  it is expected that the specified DRBG is not reseeded
 159  *      -1:  don't check whether the specified DRBG was reseeded or not
 160  * |reseed_time|: if nonzero, used instead of time(NULL) to set the
 161  *                |before_reseed| time.
 162  */
 163 static int test_drbg_reseed(int expect_success,
 164                             EVP_RAND_CTX *primary,
 165                             EVP_RAND_CTX *public,
 166                             EVP_RAND_CTX *private,
 167                             int expect_primary_reseed,
 168                             int expect_public_reseed,
 169                             int expect_private_reseed,
 170                             time_t reseed_when
 171                            )
 172 {
 173     unsigned char buf[32];
 174     time_t before_reseed, after_reseed;
 175     int expected_state = (expect_success ? DRBG_READY : DRBG_ERROR);
 176     unsigned int primary_reseed, public_reseed, private_reseed;
 177
 178     /*
 179      * step 1: check preconditions
 180      */
 181
 182     /* Test whether seed propagation is enabled */
 183     if (!TEST_int_ne(primary_reseed = reseed_counter(primary), 0)
 184         || !TEST_int_ne(public_reseed = reseed_counter(public), 0)
 185         || !TEST_int_ne(private_reseed = reseed_counter(private), 0))
 186         return 0;
 187
 188     /*
 189      * step 2: generate random output
 190      */
 191
 192     if (reseed_when == 0)
 193         reseed_when = time(NULL);
 194
 195     /* Generate random output from the public and private DRBG */
 196     before_reseed = expect_primary_reseed == 1 ? reseed_when : 0;
 197     if (!TEST_int_eq(rand_bytes(buf, sizeof(buf)), expect_success)
 198         || !TEST_int_eq(rand_priv_bytes(buf, sizeof(buf)), expect_success))
 199         return 0;
 200     after_reseed = time(NULL);
 201
 202
 203     /*
 204      * step 3: check postconditions
 205      */
 206
 207     /* Test whether reseeding succeeded as expected */
 208     if (!TEST_int_eq(state(primary), expected_state)
 209         || !TEST_int_eq(state(public), expected_state)
 210         || !TEST_int_eq(state(private), expected_state))
 211         return 0;
 212
 213     if (expect_primary_reseed >= 0) {
 214         /* Test whether primary DRBG was reseeded as expected */
 215         if (!TEST_int_ge(reseed_counter(primary), primary_reseed))
 216             return 0;
 217     }
 218
 219     if (expect_public_reseed >= 0) {
 220         /* Test whether public DRBG was reseeded as expected */
 221         if (!TEST_int_ge(reseed_counter(public), public_reseed)
 222                 || !TEST_uint_ge(reseed_counter(public),
 223                                  reseed_counter(primary)))
 224             return 0;
 225     }
 226
 227     if (expect_private_reseed >= 0) {
 228         /* Test whether public DRBG was reseeded as expected */
 229         if (!TEST_int_ge(reseed_counter(private), private_reseed)
 230                 || !TEST_uint_ge(reseed_counter(private),
 231                                  reseed_counter(primary)))
 232             return 0;
 233     }
 234
 235     if (expect_success == 1) {
 236         /* Test whether reseed time of primary DRBG is set correctly */
 237         if (!TEST_time_t_le(before_reseed, reseed_time(primary))
 238             || !TEST_time_t_le(reseed_time(primary), after_reseed))
 239             return 0;
 240
 241         /* Test whether reseed times of child DRBGs are synchronized with primary */
 242         if (!TEST_time_t_ge(reseed_time(public), reseed_time(primary))
 243             || !TEST_time_t_ge(reseed_time(private), reseed_time(primary)))
 244             return 0;
 245     } else {
 246         ERR_clear_error();
 247     }
 248
 249     return 1;
 250 }
 251
 252
 253 #if defined(OPENSSL_SYS_UNIX)
 254 /*
 255  * Test whether primary, public and private DRBG are reseeded after
 256  * forking the process.
 257  */
 258 static int test_drbg_reseed_after_fork(EVP_RAND_CTX *primary,
 259                                        EVP_RAND_CTX *public,
 260                                        EVP_RAND_CTX *private)
 261 {
 262     pid_t pid;
 263     int status=0;
 264
 265     pid = fork();
 266     if (!TEST_int_ge(pid, 0))
 267         return 0;
 268
 269     if (pid > 0) {
 270         /* I'm the parent; wait for the child and check its exit code */
 271         return TEST_int_eq(waitpid(pid, &status, 0), pid) && TEST_int_eq(status, 0);
 272     }
 273
 274     /* I'm the child; check whether all three DRBGs reseed. */
 275     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 1, 1, 1, 0)))
 276         status = 1;
 277     exit(status);
 278 }
 279 #endif
 280
 281 /*
 282  * Test whether the default rand_method (RAND_OpenSSL()) is
 283  * setup correctly, in particular whether reseeding  works
 284  * as designed.
 285  */
 286 static int test_rand_drbg_reseed(void)
 287 {
 288     EVP_RAND_CTX *primary, *public, *private;
 289     unsigned char rand_add_buf[256];
 290     int rv = 0;
 291     time_t before_reseed;
 292
 293     if (crngt_skip())
 294         return TEST_skip("CRNGT cannot be disabled");
 295
 296     /* Check whether RAND_OpenSSL() is the default method */
 297     if (!TEST_ptr_eq(RAND_get_rand_method(), RAND_OpenSSL()))
 298         return 0;
 299
 300     /* All three DRBGs should be non-null */
 301     if (!TEST_ptr(primary = RAND_get0_primary(NULL))
 302         || !TEST_ptr(public = RAND_get0_public(NULL))
 303         || !TEST_ptr(private = RAND_get0_private(NULL)))
 304         return 0;
 305
 306     /* There should be three distinct DRBGs, two of them chained to primary */
 307     if (!TEST_ptr_ne(public, private)
 308         || !TEST_ptr_ne(public, primary)
 309         || !TEST_ptr_ne(private, primary)
 310         || !TEST_ptr_eq(prov_rand(public)->parent, prov_rand(primary))
 311         || !TEST_ptr_eq(prov_rand(private)->parent, prov_rand(primary)))
 312         return 0;
 313
 314     /* Disable CRNG testing for the primary DRBG */
 315     if (!TEST_true(disable_crngt(primary)))
 316         return 0;
 317
 318     /* uninstantiate the three global DRBGs */
 319     EVP_RAND_uninstantiate(primary);
 320     EVP_RAND_uninstantiate(private);
 321     EVP_RAND_uninstantiate(public);
 322
 323
 324     /*
 325      * Test initial seeding of shared DRBGs
 326      */
 327     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 1, 1, 1, 0)))
 328         goto error;
 329
 330
 331     /*
 332      * Test initial state of shared DRBGs
 333      */
 334     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 0, 0, 0, 0)))
 335         goto error;
 336
 337     /*
 338      * Test whether the public and private DRBG are both reseeded when their
 339      * reseed counters differ from the primary's reseed counter.
 340      */
 341     inc_reseed_counter(primary);
 342     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 0, 1, 1, 0)))
 343         goto error;
 344
 345     /*
 346      * Test whether the public DRBG is reseeded when its reseed counter differs
 347      * from the primary's reseed counter.
 348      */
 349     inc_reseed_counter(primary);
 350     inc_reseed_counter(private);
 351     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 0, 1, 0, 0)))
 352         goto error;
 353
 354     /*
 355      * Test whether the private DRBG is reseeded when its reseed counter differs
 356      * from the primary's reseed counter.
 357      */
 358     inc_reseed_counter(primary);
 359     inc_reseed_counter(public);
 360     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 0, 0, 1, 0)))
 361         goto error;
 362
 363 #if defined(OPENSSL_SYS_UNIX)
 364     if (!TEST_true(test_drbg_reseed_after_fork(primary, public, private)))
 365         goto error;
 366 #endif
 367
 368     /* fill 'randomness' buffer with some arbitrary data */
 369     memset(rand_add_buf, 'r', sizeof(rand_add_buf));
 370
 371 #ifndef FIPS_MODULE
 372     /*
 373      * Test whether all three DRBGs are reseeded by RAND_add().
 374      * The before_reseed time has to be measured here and passed into the
 375      * test_drbg_reseed() test, because the primary DRBG gets already reseeded
 376      * in RAND_add(), whence the check for the condition
 377      * before_reseed <= reseed_time(primary) will fail if the time value happens
 378      * to increase between the RAND_add() and the test_drbg_reseed() call.
 379      */
 380     before_reseed = time(NULL);
 381     RAND_add(rand_add_buf, sizeof(rand_add_buf), sizeof(rand_add_buf));
 382     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 1, 1, 1,
 383                                     before_reseed)))
 384         goto error;
 385 #else /* FIPS_MODULE */
 386     /*
 387      * In FIPS mode, random data provided by the application via RAND_add()
 388      * is not considered a trusted entropy source. It is only treated as
 389      * additional_data and no reseeding is forced. This test assures that
 390      * no reseeding occurs.
 391      */
 392     before_reseed = time(NULL);
 393     RAND_add(rand_add_buf, sizeof(rand_add_buf), sizeof(rand_add_buf));
 394     if (!TEST_true(test_drbg_reseed(1, primary, public, private, 0, 0, 0,
 395                                     before_reseed)))
 396         goto error;
 397 #endif
 398
 399     rv = 1;
 400
 401 error:
 402    return rv;
 403 }
 404
 405 #if defined(OPENSSL_THREADS)
 406 static int multi_thread_rand_bytes_succeeded = 1;
 407 static int multi_thread_rand_priv_bytes_succeeded = 1;
 408
 409 static int set_reseed_time_interval(EVP_RAND_CTX *drbg, int t)
 410 {
 411     OSSL_PARAM params[2];
 412
 413     params[0] = OSSL_PARAM_construct_int(OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL,
 414                                          &t);
 415     params[1] = OSSL_PARAM_construct_end();
 416     return EVP_RAND_set_ctx_params(drbg, params);
 417 }
 418
 419 static void run_multi_thread_test(void)
 420 {
 421     unsigned char buf[256];
 422     time_t start = time(NULL);
 423     EVP_RAND_CTX *public = NULL, *private = NULL;
 424
 425     if (!TEST_ptr(public = RAND_get0_public(NULL))
 426             || !TEST_ptr(private = RAND_get0_private(NULL))
 427             || !TEST_true(set_reseed_time_interval(private, 1))
 428             || !TEST_true(set_reseed_time_interval(public, 1))) {
 429         multi_thread_rand_bytes_succeeded = 0;
 430         return;
 431     }
 432
 433     do {
 434         if (rand_bytes(buf, sizeof(buf)) <= 0)
 435             multi_thread_rand_bytes_succeeded = 0;
 436         if (rand_priv_bytes(buf, sizeof(buf)) <= 0)
 437             multi_thread_rand_priv_bytes_succeeded = 0;
 438     }
 439     while (time(NULL) - start < 5);
 440 }
 441
 442 # if defined(OPENSSL_SYS_WINDOWS)
 443
 444 typedef HANDLE thread_t;
 445
 446 static DWORD WINAPI thread_run(LPVOID arg)
 447 {
 448     run_multi_thread_test();
 449     /*
 450      * Because we're linking with a static library, we must stop each
 451      * thread explicitly, or so says OPENSSL_thread_stop(3)
 452      */
 453     OPENSSL_thread_stop();
 454     return 0;
 455 }
 456
 457 static int run_thread(thread_t *t)
 458 {
 459     *t = CreateThread(NULL, 0, thread_run, NULL, 0, NULL);
 460     return *t != NULL;
 461 }
 462
 463 static int wait_for_thread(thread_t thread)
 464 {
 465     return WaitForSingleObject(thread, INFINITE) == 0;
 466 }
 467
 468 # else
 469
 470 typedef pthread_t thread_t;
 471
 472 static void *thread_run(void *arg)
 473 {
 474     run_multi_thread_test();
 475     /*
 476      * Because we're linking with a static library, we must stop each
 477      * thread explicitly, or so says OPENSSL_thread_stop(3)
 478      */
 479     OPENSSL_thread_stop();
 480     return NULL;
 481 }
 482
 483 static int run_thread(thread_t *t)
 484 {
 485     return pthread_create(t, NULL, thread_run, NULL) == 0;
 486 }
 487
 488 static int wait_for_thread(thread_t thread)
 489 {
 490     return pthread_join(thread, NULL) == 0;
 491 }
 492
 493 # endif
 494
 495 /*
 496  * The main thread will also run the test, so we'll have THREADS+1 parallel
 497  * tests running
 498  */
 499 # define THREADS 3
 500
 501 static int test_multi_thread(void)
 502 {
 503     thread_t t[THREADS];
 504     int i;
 505
 506     for (i = 0; i < THREADS; i++)
 507         run_thread(&t[i]);
 508     run_multi_thread_test();
 509     for (i = 0; i < THREADS; i++)
 510         wait_for_thread(t[i]);
 511
 512     if (!TEST_true(multi_thread_rand_bytes_succeeded))
 513         return 0;
 514     if (!TEST_true(multi_thread_rand_priv_bytes_succeeded))
 515         return 0;
 516
 517     return 1;
 518 }
 519 #endif
 520
 521 static EVP_RAND_CTX *new_drbg(EVP_RAND_CTX *parent)
 522 {
 523     OSSL_PARAM params[2];
 524     EVP_RAND *rand = NULL;
 525     EVP_RAND_CTX *drbg = NULL;
 526
 527     params[0] = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER,
 528                                                  "AES-256-CTR", 0);
 529     params[1] = OSSL_PARAM_construct_end();
 530
 531     if (!TEST_ptr(rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL))
 532             || !TEST_ptr(drbg = EVP_RAND_CTX_new(rand, parent))
 533             || !TEST_true(EVP_RAND_set_ctx_params(drbg, params))) {
 534         EVP_RAND_CTX_free(drbg);
 535         drbg = NULL;
 536     }
 537     EVP_RAND_free(rand);
 538     return drbg;
 539 }
 540
 541 static int test_rand_drbg_prediction_resistance(void)
 542 {
 543     EVP_RAND_CTX *x = NULL, *y = NULL, *z = NULL;
 544     unsigned char buf1[51], buf2[sizeof(buf1)];
 545     int ret = 0, xreseed, yreseed, zreseed;
 546
 547     if (crngt_skip())
 548         return TEST_skip("CRNGT cannot be disabled");
 549
 550     /* Initialise a three long DRBG chain */
 551     if (!TEST_ptr(x = new_drbg(NULL))
 552         || !TEST_true(disable_crngt(x))
 553         || !TEST_true(EVP_RAND_instantiate(x, 0, 0, NULL, 0))
 554         || !TEST_ptr(y = new_drbg(x))
 555         || !TEST_true(EVP_RAND_instantiate(y, 0, 0, NULL, 0))
 556         || !TEST_ptr(z = new_drbg(y))
 557         || !TEST_true(EVP_RAND_instantiate(z, 0, 0, NULL, 0)))
 558         goto err;
 559
 560     /*
 561      * During a normal reseed, only the last DRBG in the chain should
 562      * be reseeded.
 563      */
 564     inc_reseed_counter(y);
 565     xreseed = reseed_counter(x);
 566     yreseed = reseed_counter(y);
 567     zreseed = reseed_counter(z);
 568     if (!TEST_true(EVP_RAND_reseed(z, 0, NULL, 0, NULL, 0))
 569         || !TEST_int_eq(reseed_counter(x), xreseed)
 570         || !TEST_int_eq(reseed_counter(y), yreseed)
 571         || !TEST_int_gt(reseed_counter(z), zreseed))
 572         goto err;
 573
 574     /*
 575      * When prediction resistance is requested, the request should be
 576      * propagated to the primary, so that the entire DRBG chain reseeds.
 577      */
 578     zreseed = reseed_counter(z);
 579     if (!TEST_true(EVP_RAND_reseed(z, 1, NULL, 0, NULL, 0))
 580         || !TEST_int_gt(reseed_counter(x), xreseed)
 581         || !TEST_int_gt(reseed_counter(y), yreseed)
 582         || !TEST_int_gt(reseed_counter(z), zreseed))
 583         goto err;
 584
 585     /*
 586      * During a normal generate, only the last DRBG should be reseed */
 587     inc_reseed_counter(y);
 588     xreseed = reseed_counter(x);
 589     yreseed = reseed_counter(y);
 590     zreseed = reseed_counter(z);
 591     if (!TEST_true(EVP_RAND_generate(z, buf1, sizeof(buf1), 0, 0, NULL, 0))
 592         || !TEST_int_eq(reseed_counter(x), xreseed)
 593         || !TEST_int_eq(reseed_counter(y), yreseed)
 594         || !TEST_int_gt(reseed_counter(z), zreseed))
 595         goto err;
 596
 597     /*
 598      * When a prediction resistant generate is requested, the request
 599      * should be propagated to the primary, reseeding the entire DRBG chain.
 600      */
 601     zreseed = reseed_counter(z);
 602     if (!TEST_true(EVP_RAND_generate(z, buf2, sizeof(buf2), 0, 1, NULL, 0))
 603         || !TEST_int_gt(reseed_counter(x), xreseed)
 604         || !TEST_int_gt(reseed_counter(y), yreseed)
 605         || !TEST_int_gt(reseed_counter(z), zreseed)
 606         || !TEST_mem_ne(buf1, sizeof(buf1), buf2, sizeof(buf2)))
 607         goto err;
 608
 609     /* Verify that a normal reseed still only reseeds the last DRBG */
 610     inc_reseed_counter(y);
 611     xreseed = reseed_counter(x);
 612     yreseed = reseed_counter(y);
 613     zreseed = reseed_counter(z);
 614     if (!TEST_true(EVP_RAND_reseed(z, 0, NULL, 0, NULL, 0))
 615         || !TEST_int_eq(reseed_counter(x), xreseed)
 616         || !TEST_int_eq(reseed_counter(y), yreseed)
 617         || !TEST_int_gt(reseed_counter(z), zreseed))
 618         goto err;
 619
 620     ret = 1;
 621 err:
 622     EVP_RAND_CTX_free(z);
 623     EVP_RAND_CTX_free(y);
 624     EVP_RAND_CTX_free(x);
 625     return ret;
 626 }
 627
 628 int setup_tests(void)
 629 {
 630     ADD_TEST(test_rand_drbg_reseed);
 631     ADD_TEST(test_rand_drbg_prediction_resistance);
 632 #if defined(OPENSSL_THREADS)
 633     ADD_TEST(test_multi_thread);
 634 #endif
 635     return 1;
 636 }