Merge branch '24-drivers-net'
[keystone-linux/linux.git] / samples / seccomp / bpf-fancy.c
1 /*
2  * Seccomp BPF example using a macro-based generator.
3  *
4  * Copyright (c) 2012 The Chromium OS Authors <chromium-os-dev@chromium.org>
5  * Author: Will Drewry <wad@chromium.org>
6  *
7  * The code may be used by anyone for any purpose,
8  * and can serve as a starting point for developing
9  * applications using prctl(PR_ATTACH_SECCOMP_FILTER).
10  */
12 #include <linux/filter.h>
13 #include <linux/seccomp.h>
14 #include <linux/unistd.h>
15 #include <stdio.h>
16 #include <string.h>
17 #include <sys/prctl.h>
18 #include <unistd.h>
20 #include "bpf-helper.h"
22 #ifndef PR_SET_NO_NEW_PRIVS
23 #define PR_SET_NO_NEW_PRIVS 38
24 #endif
26 int main(int argc, char **argv)
27 {
28         struct bpf_labels l;
29         static const char msg1[] = "Please type something: ";
30         static const char msg2[] = "You typed: ";
31         char buf[256];
32         struct sock_filter filter[] = {
33                 /* TODO: LOAD_SYSCALL_NR(arch) and enforce an arch */
34                 LOAD_SYSCALL_NR,
35                 SYSCALL(__NR_exit, ALLOW),
36                 SYSCALL(__NR_exit_group, ALLOW),
37                 SYSCALL(__NR_write, JUMP(&l, write_fd)),
38                 SYSCALL(__NR_read, JUMP(&l, read)),
39                 DENY,  /* Don't passthrough into a label */
41                 LABEL(&l, read),
42                 ARG(0),
43                 JNE(STDIN_FILENO, DENY),
44                 ARG(1),
45                 JNE((unsigned long)buf, DENY),
46                 ARG(2),
47                 JGE(sizeof(buf), DENY),
48                 ALLOW,
50                 LABEL(&l, write_fd),
51                 ARG(0),
52                 JEQ(STDOUT_FILENO, JUMP(&l, write_buf)),
53                 JEQ(STDERR_FILENO, JUMP(&l, write_buf)),
54                 DENY,
56                 LABEL(&l, write_buf),
57                 ARG(1),
58                 JEQ((unsigned long)msg1, JUMP(&l, msg1_len)),
59                 JEQ((unsigned long)msg2, JUMP(&l, msg2_len)),
60                 JEQ((unsigned long)buf, JUMP(&l, buf_len)),
61                 DENY,
63                 LABEL(&l, msg1_len),
64                 ARG(2),
65                 JLT(sizeof(msg1), ALLOW),
66                 DENY,
68                 LABEL(&l, msg2_len),
69                 ARG(2),
70                 JLT(sizeof(msg2), ALLOW),
71                 DENY,
73                 LABEL(&l, buf_len),
74                 ARG(2),
75                 JLT(sizeof(buf), ALLOW),
76                 DENY,
77         };
78         struct sock_fprog prog = {
79                 .filter = filter,
80                 .len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
81         };
82         ssize_t bytes;
83         bpf_resolve_jumps(&l, filter, sizeof(filter)/sizeof(*filter));
85         if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
86                 perror("prctl(NO_NEW_PRIVS)");
87                 return 1;
88         }
90         if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog)) {
91                 perror("prctl(SECCOMP)");
92                 return 1;
93         }
94         syscall(__NR_write, STDOUT_FILENO, msg1, strlen(msg1));
95         bytes = syscall(__NR_read, STDIN_FILENO, buf, sizeof(buf)-1);
96         bytes = (bytes > 0 ? bytes : 0);
97         syscall(__NR_write, STDERR_FILENO, msg2, strlen(msg2));
98         syscall(__NR_write, STDERR_FILENO, buf, bytes);
99         /* Now get killed */
100         syscall(__NR_write, STDERR_FILENO, msg2, strlen(msg2)+2);
101         return 0;