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 <openssl/opensslconf.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 void OPENSSL_cpuid_setup(void);
  24
  25 extern unsigned int OPENSSL_ia32cap_P[4];
  26
  27 static int sanity_check_bytes(size_t (*rng)(unsigned char *, size_t),
  28     int rounds, int min_failures, int max_retries, int max_zero_words)
  29 {
  30     int testresult = 0;
  31     unsigned char prior[31] = {0}, buf[31] = {0}, check[7];
  32     int failures = 0, zero_words = 0;
  33
  34     int i;
  35     for (i = 0; i < rounds; i++) {
  36         size_t generated = 0;
  37
  38         int retry;
  39         for (retry = 0; retry < max_retries; retry++) {
  40             generated = rng(buf, sizeof(buf));
  41             if (generated == sizeof(buf))
  42                 break;
  43             failures++;
  44         }
  45
  46         /*-
  47          * Verify that we don't have too many unexpected runs of zeroes,
  48          * implying that we might be accidentally using the 32-bit RDRAND
  49          * instead of the 64-bit one on 64-bit systems.
  50          */
  51         size_t j;
  52         for (j = 0; j < sizeof(buf) - 1; j++) {
  53             if (buf[j] == 0 && buf[j+1] == 0) {
  54                 zero_words++;
  55             }
  56         }
  57
  58         if (!TEST_int_eq(generated, sizeof(buf)))
  59             goto end;
  60         if (!TEST_false(!memcmp(prior, buf, sizeof(buf))))
  61             goto end;
  62
  63         /* Verify that the last 7 bytes of buf aren't all the same value */
  64         unsigned char *tail = &buf[sizeof(buf) - sizeof(check)];
  65         memset(check, tail[0], 7);
  66         if (!TEST_false(!memcmp(check, tail, sizeof(check))))
  67             goto end;
  68
  69         /* Save the result and make sure it's different next time */
  70         memcpy(prior, buf, sizeof(buf));
  71     }
  72
  73     if (!TEST_int_le(zero_words, max_zero_words))
  74         goto end;
  75
  76     if (!TEST_int_ge(failures, min_failures))
  77         goto end;
  78
  79     testresult = 1;
  80 end:
  81     return testresult;
  82 }
  83
  84 static int sanity_check_rdrand_bytes(void)
  85 {
  86     return sanity_check_bytes(OPENSSL_ia32_rdrand_bytes, 1000, 0, 10, 10);
  87 }
  88
  89 static int sanity_check_rdseed_bytes(void)
  90 {
  91     /*-
  92      * RDSEED may take many retries to succeed; note that this is effectively
  93      * multiplied by the 8x retry loop in asm, and failure probabilities are
  94      * increased by the fact that we need either 4 or 8 samples depending on
  95      * the platform.
  96      */
  97     return sanity_check_bytes(OPENSSL_ia32_rdseed_bytes, 1000, 1, 10000, 10);
  98 }
  99
 100 int setup_tests(void)
 101 {
 102     OPENSSL_cpuid_setup();
 103
 104     int have_rdseed = (OPENSSL_ia32cap_P[2] & (1 << 18)) != 0;
 105     int have_rdrand = (OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0;
 106
 107     if (have_rdrand) {
 108         ADD_TEST(sanity_check_rdrand_bytes);
 109     }
 110
 111     if (have_rdseed) {
 112         ADD_TEST(sanity_check_rdseed_bytes);
 113     }
 114
 115     return 1;
 116 }
 117
 118
 119 #else
 120
 121 int setup_tests(void)
 122 {
 123     return 1;
 124 }
 125
 126 #endif