1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/random.h>
34#include <errno.h>
35
36#include <atf-c.h>
37
38#include <zstd.h>
39
40static const unsigned valid_flags[] = { 0, GRND_NONBLOCK, GRND_RANDOM,
41    GRND_NONBLOCK | GRND_RANDOM };
42
43ATF_TC_WITHOUT_HEAD(getrandom_randomness);
44ATF_TC_BODY(getrandom_randomness, tc)
45{
46	char randomb[4096], compressed[5000];
47	ssize_t ret;
48	size_t i, j, c;
49	unsigned mode;
50
51	for (i = 0; i < nitems(valid_flags); i++) {
52		mode = valid_flags[i];
53
54		/* Get new random data, filling randomb. */
55
56		memset(randomb, 0, sizeof(randomb));
57
58		for (j = 0; j < sizeof(randomb);) {
59			ret = getrandom(&randomb[j], sizeof(randomb) - j, mode);
60			if (ret < 0 && (mode & GRND_NONBLOCK) != 0 &&
61			    errno == EAGAIN)
62				continue;
63
64			ATF_REQUIRE_MSG(ret >= 0, "other error: %d", errno);
65			ATF_REQUIRE_MSG(ret > 0, "bogus zero return");
66
67			j += (size_t)ret;
68		}
69
70		/* Perform compressibility test */
71		c = ZSTD_compress(compressed, sizeof(compressed), randomb,
72		    sizeof(randomb), ZSTD_maxCLevel());
73		ATF_REQUIRE_MSG(!ZSTD_isError(c), "zstd compress: %s",
74		    ZSTD_getErrorName(c));
75
76		/*
77		 * If the output is very compressible, it's probably not random
78		 */
79		ATF_REQUIRE_MSG(c > (sizeof(randomb) * 4 / 5),
80		    "purportedly random data was compressible: %zu/%zu or %f%%",
81		    c, sizeof(randomb), (double)c / (double)sizeof(randomb));
82	}
83}
84
85ATF_TC_WITHOUT_HEAD(getrandom_fault);
86ATF_TC_BODY(getrandom_fault, tc)
87{
88	ssize_t ret;
89
90	ret = getrandom(NULL, 1, 0);
91	ATF_REQUIRE_EQ(ret, -1);
92	ATF_REQUIRE_EQ(errno, EFAULT);
93}
94
95ATF_TC_WITHOUT_HEAD(getrandom_count);
96ATF_TC_BODY(getrandom_count, tc)
97{
98	char buf[4096], reference[4096];
99	ssize_t ret;
100
101	/* getrandom(2) does not modify buf past the requested length */
102	_Static_assert(sizeof(reference) == sizeof(buf), "must match");
103	memset(reference, 0x7C, sizeof(reference));
104
105	memset(buf, 0x7C, sizeof(buf));
106	ret = getrandom(buf, 1, 0);
107	ATF_REQUIRE_EQ(ret, 1);
108	ATF_REQUIRE_EQ(memcmp(&buf[1], reference, sizeof(reference) - 1), 0);
109
110	memset(buf, 0x7C, sizeof(buf));
111	ATF_REQUIRE_EQ(getrandom(buf, 15, 0), 15);
112	ATF_REQUIRE_EQ(memcmp(&buf[15], reference, sizeof(reference) - 15), 0);
113
114	memset(buf, 0x7C, sizeof(buf));
115	ATF_REQUIRE_EQ(getrandom(buf, 255, 0), 255);
116	ATF_REQUIRE_EQ(memcmp(&buf[255], reference, sizeof(reference) - 255), 0);
117
118	memset(buf, 0x7C, sizeof(buf));
119	ATF_REQUIRE_EQ(getrandom(buf, 4095, 0), 4095);
120	ATF_REQUIRE_EQ(memcmp(&buf[4095], reference, sizeof(reference) - 4095), 0);
121}
122
123ATF_TP_ADD_TCS(tp)
124{
125
126	ATF_TP_ADD_TC(tp, getrandom_count);
127	ATF_TP_ADD_TC(tp, getrandom_fault);
128	ATF_TP_ADD_TC(tp, getrandom_randomness);
129	return (atf_no_error());
130}
131