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/types.h>
28 #include <sys/mman.h>
29 #include <sys/wait.h>
30 #include <errno.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35
36 #include <atf-c.h>
37
38 /*
39 * BUFSIZE is the number of bytes of rc4 output to compare. The probability
40 * that this test fails spuriously is 2**(-BUFSIZE * 8).
41 */
42 #define BUFSIZE 8
43
44 /*
45 * Test whether arc4random_buf() returns the same sequence of bytes in both
46 * parent and child processes. (Hint: It shouldn't.)
47 */
48 ATF_TC_WITHOUT_HEAD(test_arc4random);
ATF_TC_BODY(test_arc4random,tc)49 ATF_TC_BODY(test_arc4random, tc)
50 {
51 struct shared_page {
52 char parentbuf[BUFSIZE];
53 char childbuf[BUFSIZE];
54 } *page;
55 pid_t pid;
56 char c;
57
58 page = mmap(NULL, sizeof(struct shared_page), PROT_READ | PROT_WRITE,
59 MAP_ANON | MAP_SHARED, -1, 0);
60 ATF_REQUIRE_MSG(page != MAP_FAILED, "mmap failed; errno=%d", errno);
61
62 arc4random_buf(&c, 1);
63
64 pid = fork();
65 ATF_REQUIRE(0 <= pid);
66 if (pid == 0) {
67 /* child */
68 arc4random_buf(page->childbuf, BUFSIZE);
69 exit(0);
70 } else {
71 /* parent */
72 int status;
73 arc4random_buf(page->parentbuf, BUFSIZE);
74 wait(&status);
75 }
76 ATF_CHECK_MSG(memcmp(page->parentbuf, page->childbuf, BUFSIZE) != 0,
77 "sequences are the same");
78 }
79
ATF_TP_ADD_TCS(tp)80 ATF_TP_ADD_TCS(tp)
81 {
82
83 ATF_TP_ADD_TC(tp, test_arc4random);
84
85 return (atf_no_error());
86 }
87