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); 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 80 ATF_TP_ADD_TCS(tp) 81 { 82 83 ATF_TP_ADD_TC(tp, test_arc4random); 84 85 return (atf_no_error()); 86 } 87