test/rdrand_sanitytest.c

   1 /*
   2  * Copyright 2018 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 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include "testutil.h"
  14 #include "internal/cryptlib.h"
  15
  16 #if (defined(__i386)   || defined(__i386__)   || defined(_M_IX86) || \
  17      defined(__x86_64) || defined(__x86_64__) || \
  18      defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
  19
  20 size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
  21 size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
  22
  23 static int sanity_check_bytes(size_t (*rng)(unsigned char *, size_t),
  24     int rounds, int min_failures, int max_retries, int max_zero_words)
  25 {
  26     int testresult = 0;
  27     unsigned char prior[31] = {0}, buf[31] = {0}, check[7];
  28     int failures = 0, zero_words = 0;
  29
  30     int i;
  31     for (i = 0; i < rounds; i++) {
  32         size_t generated = 0;
  33
  34         int retry;
  35         for (retry = 0; retry < max_retries; retry++) {
  36             generated = rng(buf, sizeof(buf));
  37             if (generated == sizeof(buf))
  38                 break;
  39             failures++;
  40         }
  41
  42         /*-
  43          * Verify that we don't have too many unexpected runs of zeroes,
  44          * implying that we might be accidentally using the 32-bit RDRAND
  45          * instead of the 64-bit one on 64-bit systems.
  46          */
  47         size_t j;
  48         for (j = 0; j < sizeof(buf) - 1; j++) {
  49             if (buf[j] == 0 && buf[j+1] == 0) {
  50                 zero_words++;
  51             }
  52         }
  53
  54         if (!TEST_int_eq(generated, sizeof(buf)))
  55             goto end;
  56         if (!TEST_false(!memcmp(prior, buf, sizeof(buf))))
  57             goto end;
  58
  59         /* Verify that the last 7 bytes of buf aren't all the same value */
  60         unsigned char *tail = &buf[sizeof(buf) - sizeof(check)];
  61         memset(check, tail[0], 7);
  62         if (!TEST_false(!memcmp(check, tail, sizeof(check))))
  63             goto end;
  64
  65         /* Save the result and make sure it's different next time */
  66         memcpy(prior, buf, sizeof(buf));
  67     }
  68
  69     if (!TEST_int_le(zero_words, max_zero_words))
  70         goto end;
  71
  72     if (!TEST_int_ge(failures, min_failures))
  73         goto end;
  74
  75     testresult = 1;
  76 end:
  77     return testresult;
  78 }
  79
  80 static int sanity_check_rdrand_bytes(void)
  81 {
  82     return sanity_check_bytes(OPENSSL_ia32_rdrand_bytes, 1000, 0, 10, 10);
  83 }
  84
  85 static int sanity_check_rdseed_bytes(void)
  86 {
  87     /*-
  88      * RDSEED may take many retries to succeed; note that this is effectively
  89      * multiplied by the 8x retry loop in asm, and failure probabilities are
  90      * increased by the fact that we need either 4 or 8 samples depending on
  91      * the platform.
  92      */
  93     return sanity_check_bytes(OPENSSL_ia32_rdseed_bytes, 1000, 1, 10000, 10);
  94 }
  95
  96 int setup_tests(void)
  97 {
  98     OPENSSL_cpuid_setup();
  99
 100     int have_rdseed = (OPENSSL_ia32cap_P[2] & (1 << 18)) != 0;
 101     int have_rdrand = (OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0;
 102
 103     if (have_rdrand) {
 104         ADD_TEST(sanity_check_rdrand_bytes);
 105     }
 106
 107     if (have_rdseed) {
 108         ADD_TEST(sanity_check_rdseed_bytes);
 109     }
 110
 111     return 1;
 112 }
 113
 114
 115 #else
 116
 117 int setup_tests(void)
 118 {
 119     return 1;
 120 }
 121
 122 #endif