1/*-
2 * Copyright (c) 2011 David Schultz
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/types.h>
31#include <sys/mman.h>
32#include <sys/wait.h>
33#include <errno.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38
39#include <atf-c.h>
40
41/*
42 * BUFSIZE is the number of bytes of rc4 output to compare.  The probability
43 * that this test fails spuriously is 2**(-BUFSIZE * 8).
44 */
45#define	BUFSIZE		8
46
47/*
48 * Test whether arc4random_buf() returns the same sequence of bytes in both
49 * parent and child processes.  (Hint: It shouldn't.)
50 */
51ATF_TC_WITHOUT_HEAD(test_arc4random);
52ATF_TC_BODY(test_arc4random, tc)
53{
54	struct shared_page {
55		char parentbuf[BUFSIZE];
56		char childbuf[BUFSIZE];
57	} *page;
58	pid_t pid;
59	char c;
60
61	page = mmap(NULL, sizeof(struct shared_page), PROT_READ | PROT_WRITE,
62		    MAP_ANON | MAP_SHARED, -1, 0);
63	ATF_REQUIRE_MSG(page != MAP_FAILED, "mmap failed; errno=%d", errno);
64
65	arc4random_buf(&c, 1);
66
67	pid = fork();
68	ATF_REQUIRE(0 <= pid);
69	if (pid == 0) {
70		/* child */
71		arc4random_buf(page->childbuf, BUFSIZE);
72		exit(0);
73	} else {
74		/* parent */
75		int status;
76		arc4random_buf(page->parentbuf, BUFSIZE);
77		wait(&status);
78	}
79	ATF_CHECK_MSG(memcmp(page->parentbuf, page->childbuf, BUFSIZE) != 0,
80	    "sequences are the same");
81}
82
83ATF_TP_ADD_TCS(tp)
84{
85
86	ATF_TP_ADD_TC(tp, test_arc4random);
87
88	return (atf_no_error());
89}
90