1 /*
2 * Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
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 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #ifdef HAVE_CONFIG_H
29 # include "config.h"
30 #endif
31 #include <dlfcn.h>
32 #include <fcntl.h>
33 #include <unistd.h>
34 #include <sys/mman.h>
35 #include <sys/wait.h>
36 #include <sys/sendfile.h>
37
main(void)38 int main(void)
39 {
40 const unsigned long pagesize = sysconf(_SC_PAGESIZE);
41
42 #ifdef __s390__
43 /*
44 * The si_addr field is unreliable:
45 * https://marc.info/?l=linux-s390&m=142515870124248&w=2
46 */
47 return 77;
48 #endif
49
50 /* write instruction pointer length to the log */
51 if (write(-1, NULL, 2 * sizeof(void *)) >= 0)
52 return 77;
53
54 /* just a noticeable line in the log */
55 if (munmap(&main, 0) >= 0)
56 return 77;
57
58 int pid = fork();
59 if (pid < 0)
60 return 77;
61
62 if (!pid) {
63 const unsigned long mask = ~(pagesize - 1);
64 unsigned long addr = (unsigned long) &main & mask;
65 unsigned long size = pagesize << 1;
66
67 #ifdef HAVE_DLADDR
68 Dl_info info;
69 if (dladdr(&main, &info)) {
70 const unsigned long base =
71 (unsigned long) info.dli_fbase & mask;
72 if (base < addr) {
73 size += addr - base;
74 addr = base;
75 }
76 } else
77 #endif
78 {
79 addr -= size;
80 size <<= 1;
81 }
82
83 /* SIGSEGV is expected */
84 (void) munmap((void *) addr, size);
85 (void) munmap((void *) addr, size);
86 return 77;
87 }
88
89 int status;
90 if (wait(&status) != pid ||
91 !WIFSIGNALED(status) ||
92 WTERMSIG(status) != SIGSEGV)
93 return 77;
94
95 /* dump process map for debug purposes */
96 close(0);
97 if (!open("/proc/self/maps", O_RDONLY))
98 (void) sendfile(1, 0, NULL, pagesize);
99
100 return 0;
101 }
102