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 #include <sys/types.h> 29 #include <sys/mman.h> 30 #include <sys/wait.h> 31 #include <errno.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <unistd.h> 36 37 #include <atf-c.h> 38 39 /* 40 * BUFSIZE is the number of bytes of rc4 output to compare. The probability 41 * that this test fails spuriously is 2**(-BUFSIZE * 8). 42 */ 43 #define BUFSIZE 8 44 45 /* 46 * Test whether arc4random_buf() returns the same sequence of bytes in both 47 * parent and child processes. (Hint: It shouldn't.) 48 */ 49 ATF_TC_WITHOUT_HEAD(test_arc4random); 50 ATF_TC_BODY(test_arc4random, tc) 51 { 52 struct shared_page { 53 char parentbuf[BUFSIZE]; 54 char childbuf[BUFSIZE]; 55 } *page; 56 pid_t pid; 57 char c; 58 59 page = mmap(NULL, sizeof(struct shared_page), PROT_READ | PROT_WRITE, 60 MAP_ANON | MAP_SHARED, -1, 0); 61 ATF_REQUIRE_MSG(page != MAP_FAILED, "mmap failed; errno=%d", errno); 62 63 arc4random_buf(&c, 1); 64 65 pid = fork(); 66 ATF_REQUIRE(0 <= pid); 67 if (pid == 0) { 68 /* child */ 69 arc4random_buf(page->childbuf, BUFSIZE); 70 exit(0); 71 } else { 72 /* parent */ 73 int status; 74 arc4random_buf(page->parentbuf, BUFSIZE); 75 wait(&status); 76 } 77 ATF_CHECK_MSG(memcmp(page->parentbuf, page->childbuf, BUFSIZE) != 0, 78 "sequences are the same"); 79 } 80 81 ATF_TP_ADD_TCS(tp) 82 { 83 84 ATF_TP_ADD_TC(tp, test_arc4random); 85 86 return (atf_no_error()); 87 } 88