1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
/**
* Seccomp Library test program
*
* Copyright (c) 2018 Oracle and/or its affiliates. All rights reserved.
* Author: Tom Hromatka <tom.hromatka@oracle.com>
*/
/*
* This library is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser General Public License as
* published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, see <http://www.gnu.org/licenses>.
*/
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <seccomp.h>
#include "util.h"
static const unsigned int allowlist[] = {
SCMP_SYS(clone),
SCMP_SYS(exit),
SCMP_SYS(exit_group),
SCMP_SYS(futex),
SCMP_SYS(madvise),
SCMP_SYS(mmap),
SCMP_SYS(mprotect),
SCMP_SYS(munmap),
SCMP_SYS(nanosleep),
SCMP_SYS(set_robust_list),
};
/**
* Child thread created via pthread_create()
*
* This thread will call a disallowed syscall. It should
* cause the entire program to die (and not just this
* thread.)
*/
void *child_start(void *param)
{
int fd;
/* make a disallowed syscall */
fd = open("/dev/null", O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
/* we should never get here. seccomp should kill the entire
* process when open() is called. */
if (fd >= 0)
close(fd);
return NULL;
}
int main(int argc, char *argv[])
{
int rc, i;
scmp_filter_ctx ctx = NULL;
pthread_t child_thread;
ctx = seccomp_init(SCMP_ACT_KILL_PROCESS);
if (ctx == NULL)
return ENOMEM;
for (i = 0; i < sizeof(allowlist) / sizeof(allowlist[0]); i++) {
rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, allowlist[i], 0);
if (rc != 0)
goto out;
}
rc = seccomp_load(ctx);
if (rc != 0)
goto out;
rc = pthread_create(&child_thread, NULL, child_start, NULL);
if (rc != 0)
goto out;
/* sleep for a bit to ensure that the child thread has time to run */
sleep(1);
/* we should never get here! */
rc = -EACCES;
goto out;
out:
seccomp_release(ctx);
return (rc < 0 ? -rc : rc);
}
|
