1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/param.h>
30#include <sys/random.h>
31#include <errno.h>
32
33#include <atf-c.h>
34
35#include <zstd.h>
36
37static const unsigned valid_flags[] = { 0, GRND_NONBLOCK, GRND_RANDOM,
38    GRND_NONBLOCK | GRND_RANDOM };
39
40ATF_TC_WITHOUT_HEAD(getrandom_randomness);
41ATF_TC_BODY(getrandom_randomness, tc)
42{
43	char randomb[4096], compressed[5000];
44	ssize_t ret;
45	size_t i, j, c;
46	unsigned mode;
47
48	for (i = 0; i < nitems(valid_flags); i++) {
49		mode = valid_flags[i];
50
51		/* Get new random data, filling randomb. */
52
53		memset(randomb, 0, sizeof(randomb));
54
55		for (j = 0; j < sizeof(randomb);) {
56			ret = getrandom(&randomb[j], sizeof(randomb) - j, mode);
57			if (ret < 0 && (mode & GRND_NONBLOCK) != 0 &&
58			    errno == EAGAIN)
59				continue;
60
61			ATF_REQUIRE_MSG(ret >= 0, "other error: %d", errno);
62			ATF_REQUIRE_MSG(ret > 0, "bogus zero return");
63
64			j += (size_t)ret;
65		}
66
67		/* Perform compressibility test */
68		c = ZSTD_compress(compressed, sizeof(compressed), randomb,
69		    sizeof(randomb), ZSTD_maxCLevel());
70		ATF_REQUIRE_MSG(!ZSTD_isError(c), "zstd compress: %s",
71		    ZSTD_getErrorName(c));
72
73		/*
74		 * If the output is very compressible, it's probably not random
75		 */
76		ATF_REQUIRE_MSG(c > (sizeof(randomb) * 4 / 5),
77		    "purportedly random data was compressible: %zu/%zu or %f%%",
78		    c, sizeof(randomb), (double)c / (double)sizeof(randomb));
79	}
80}
81
82ATF_TC_WITHOUT_HEAD(getrandom_fault);
83ATF_TC_BODY(getrandom_fault, tc)
84{
85	ssize_t ret;
86
87	ret = getrandom(NULL, 1, 0);
88	ATF_REQUIRE_EQ(ret, -1);
89	ATF_REQUIRE_EQ(errno, EFAULT);
90}
91
92ATF_TC_WITHOUT_HEAD(getrandom_count);
93ATF_TC_BODY(getrandom_count, tc)
94{
95	char buf[4096], reference[4096];
96	ssize_t ret;
97
98	/* getrandom(2) does not modify buf past the requested length */
99	_Static_assert(sizeof(reference) == sizeof(buf), "must match");
100	memset(reference, 0x7C, sizeof(reference));
101
102	memset(buf, 0x7C, sizeof(buf));
103	ret = getrandom(buf, 1, 0);
104	ATF_REQUIRE_EQ(ret, 1);
105	ATF_REQUIRE_EQ(memcmp(&buf[1], reference, sizeof(reference) - 1), 0);
106
107	memset(buf, 0x7C, sizeof(buf));
108	ATF_REQUIRE_EQ(getrandom(buf, 15, 0), 15);
109	ATF_REQUIRE_EQ(memcmp(&buf[15], reference, sizeof(reference) - 15), 0);
110
111	memset(buf, 0x7C, sizeof(buf));
112	ATF_REQUIRE_EQ(getrandom(buf, 255, 0), 255);
113	ATF_REQUIRE_EQ(memcmp(&buf[255], reference, sizeof(reference) - 255), 0);
114
115	memset(buf, 0x7C, sizeof(buf));
116	ATF_REQUIRE_EQ(getrandom(buf, 4095, 0), 4095);
117	ATF_REQUIRE_EQ(memcmp(&buf[4095], reference, sizeof(reference) - 4095), 0);
118}
119
120ATF_TP_ADD_TCS(tp)
121{
122
123	ATF_TP_ADD_TC(tp, getrandom_count);
124	ATF_TP_ADD_TC(tp, getrandom_fault);
125	ATF_TP_ADD_TC(tp, getrandom_randomness);
126	return (atf_no_error());
127}
128