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      1 /*
      2  * Copyright 2018-2019 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 
     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
    127