rdrand_sanitytest.c 3.4 KB

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  1. /*
  2. * Copyright 2018 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. #include <stdio.h>
  10. #include <stdlib.h>
  11. #include <string.h>
  12. #include "testutil.h"
  13. #include <openssl/opensslconf.h>
  14. #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
  15. defined(__x86_64) || defined(__x86_64__) || \
  16. defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
  17. size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
  18. size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
  19. void OPENSSL_cpuid_setup();
  20. extern unsigned int OPENSSL_ia32cap_P[4];
  21. static int sanity_check_bytes(size_t (*rng)(unsigned char *, size_t),
  22. int rounds, int min_failures, int max_retries, int max_zero_words)
  23. {
  24. int testresult = 0;
  25. unsigned char prior[31] = {0}, buf[31] = {0}, check[7];
  26. int failures = 0, zero_words = 0;
  27. int i;
  28. for (i = 0; i < rounds; i++) {
  29. size_t generated = 0;
  30. int retry;
  31. for (retry = 0; retry < max_retries; retry++) {
  32. generated = rng(buf, sizeof(buf));
  33. if (generated == sizeof(buf))
  34. break;
  35. failures++;
  36. }
  37. /*-
  38. * Verify that we don't have too many unexpected runs of zeroes,
  39. * implying that we might be accidentally using the 32-bit RDRAND
  40. * instead of the 64-bit one on 64-bit systems.
  41. */
  42. size_t j;
  43. for (j = 0; j < sizeof(buf) - 1; j++) {
  44. if (buf[j] == 0 && buf[j+1] == 0) {
  45. zero_words++;
  46. }
  47. }
  48. if (!TEST_int_eq(generated, sizeof(buf)))
  49. goto end;
  50. if (!TEST_false(!memcmp(prior, buf, sizeof(buf))))
  51. goto end;
  52. /* Verify that the last 7 bytes of buf aren't all the same value */
  53. unsigned char *tail = &buf[sizeof(buf) - sizeof(check)];
  54. memset(check, tail[0], 7);
  55. if (!TEST_false(!memcmp(check, tail, sizeof(check))))
  56. goto end;
  57. /* Save the result and make sure it's different next time */
  58. memcpy(prior, buf, sizeof(buf));
  59. }
  60. if (!TEST_int_le(zero_words, max_zero_words))
  61. goto end;
  62. if (!TEST_int_ge(failures, min_failures))
  63. goto end;
  64. testresult = 1;
  65. end:
  66. return testresult;
  67. }
  68. static int sanity_check_rdrand_bytes()
  69. {
  70. return sanity_check_bytes(OPENSSL_ia32_rdrand_bytes, 1000, 0, 10, 10);
  71. }
  72. static int sanity_check_rdseed_bytes()
  73. {
  74. /*-
  75. * RDSEED may take many retries to succeed; note that this is effectively
  76. * multiplied by the 8x retry loop in asm, and failure probabilities are
  77. * increased by the fact that we need either 4 or 8 samples depending on
  78. * the platform.
  79. */
  80. return sanity_check_bytes(OPENSSL_ia32_rdseed_bytes, 1000, 1, 10000, 10);
  81. }
  82. int setup_tests() {
  83. OPENSSL_cpuid_setup();
  84. int have_rdseed = (OPENSSL_ia32cap_P[2] & (1 << 18)) != 0;
  85. int have_rdrand = (OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0;
  86. if (have_rdrand) {
  87. ADD_TEST(sanity_check_rdrand_bytes);
  88. }
  89. if (have_rdseed) {
  90. ADD_TEST(sanity_check_rdseed_bytes);
  91. }
  92. return 1;
  93. }
  94. #else
  95. int setup_tests()
  96. {
  97. return 1;
  98. }
  99. #endif