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
sanity_check_bytes(size_t (* rng)(unsigned char *,size_t),int rounds,int min_failures,int max_retries,int max_zero_words)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
sanity_check_rdrand_bytes(void)80 static int sanity_check_rdrand_bytes(void)
81 {
82 return sanity_check_bytes(OPENSSL_ia32_rdrand_bytes, 1000, 0, 10, 10);
83 }
84
sanity_check_rdseed_bytes(void)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
setup_tests(void)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
setup_tests(void)117 int setup_tests(void)
118 {
119 return 1;
120 }
121
122 #endif
123