1 /*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source. A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12 /*
13 * Copyright (c) 2015, Joyent, Inc.
14 */
15
16 /*
17 * Tests to make sure that a parent and child do not get the same arc4random
18 * state across a fork from a signal handler. This source file is used to make
19 * two tests. One which initializes the data in advance, one of which does not.
20 */
21
22 #include <stdlib.h>
23 #include <sys/mman.h>
24 #include <assert.h>
25 #include <errno.h>
26 #include <sys/types.h>
27 #include <unistd.h>
28 #include <sys/wait.h>
29 #include <signal.h>
30 #include <strings.h>
31
32 typedef struct arc4_fork {
33 uint32_t af_parent;
34 uint32_t af_child;
35 uint8_t af_pbuf[4096];
36 uint8_t af_cbuf[4096];
37 } arc4_fork_t;
38
39 arc4_fork_t *fork_data;
40 static pid_t pid;
41
42 /*ARGSUSED*/
43 static void
siguser_fork(int sig,siginfo_t * sip,void * ucp)44 siguser_fork(int sig, siginfo_t *sip, void *ucp)
45 {
46 pid = fork();
47 }
48
49 int
main(void)50 main(void)
51 {
52 int e, i, ret;
53 pid_t child;
54 struct sigaction sact;
55
56 bzero(&sact, sizeof (struct sigaction));
57 sact.sa_flags = SA_SIGINFO;
58 sact.sa_sigaction = siguser_fork;
59
60 (void) sigemptyset(&sact.sa_mask);
61 ret = sigaction(SIGUSR1, &sact, NULL);
62 assert(ret == 0);
63
64 #ifdef ARC4_PREINIT
65 (void) arc4random();
66 #endif
67
68 fork_data = (arc4_fork_t *)mmap(NULL, sizeof (arc4_fork_t),
69 PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
70 assert(fork_data != MAP_FAILED);
71
72 ret = raise(SIGUSR1);
73 assert(ret == 0);
74 assert(pid != -1);
75 if (pid == 0) {
76 fork_data->af_child = arc4random();
77 arc4random_buf(fork_data->af_cbuf, sizeof (fork_data->af_cbuf));
78 exit(0);
79 }
80
81 fork_data->af_parent = arc4random();
82 arc4random_buf(fork_data->af_pbuf, sizeof (fork_data->af_pbuf));
83 do {
84 child = wait(&e);
85 } while (child == -1 && errno == EINTR);
86 assert(child == pid);
87
88 /* Now verify our data doesn't match */
89 assert(fork_data->af_parent != fork_data->af_child);
90
91 /*
92 * For the buffer here, we're mostly concerned that they aren't somehow
93 * getting the same stream.
94 */
95 for (i = 0; i < sizeof (fork_data->af_pbuf); i++) {
96 if (fork_data->af_pbuf[i] != fork_data->af_cbuf[i])
97 break;
98 }
99 assert(i != sizeof (fork_data->af_pbuf));
100
101 return (0);
102 }
103