1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * Copyright © 2019 Alexey Dobriyan <adobriyan@gmail.com>
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Permission to use, copy, modify, and distribute this software for any
5*4882a593Smuzhiyun * purpose with or without fee is hereby granted, provided that the above
6*4882a593Smuzhiyun * copyright notice and this permission notice appear in all copies.
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9*4882a593Smuzhiyun * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10*4882a593Smuzhiyun * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11*4882a593Smuzhiyun * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12*4882a593Smuzhiyun * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13*4882a593Smuzhiyun * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14*4882a593Smuzhiyun * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15*4882a593Smuzhiyun */
16*4882a593Smuzhiyun /*
17*4882a593Smuzhiyun * Test that setns(CLONE_NEWNET) points to new /proc/net content even
18*4882a593Smuzhiyun * if old one is in dcache.
19*4882a593Smuzhiyun *
20*4882a593Smuzhiyun * FIXME /proc/net/unix is under CONFIG_UNIX which can be disabled.
21*4882a593Smuzhiyun */
22*4882a593Smuzhiyun #undef NDEBUG
23*4882a593Smuzhiyun #include <assert.h>
24*4882a593Smuzhiyun #include <errno.h>
25*4882a593Smuzhiyun #include <sched.h>
26*4882a593Smuzhiyun #include <signal.h>
27*4882a593Smuzhiyun #include <stdio.h>
28*4882a593Smuzhiyun #include <stdlib.h>
29*4882a593Smuzhiyun #include <string.h>
30*4882a593Smuzhiyun #include <unistd.h>
31*4882a593Smuzhiyun #include <sys/types.h>
32*4882a593Smuzhiyun #include <sys/stat.h>
33*4882a593Smuzhiyun #include <fcntl.h>
34*4882a593Smuzhiyun #include <sys/socket.h>
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun static pid_t pid = -1;
37*4882a593Smuzhiyun
f(void)38*4882a593Smuzhiyun static void f(void)
39*4882a593Smuzhiyun {
40*4882a593Smuzhiyun if (pid > 0) {
41*4882a593Smuzhiyun kill(pid, SIGTERM);
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
main(void)45*4882a593Smuzhiyun int main(void)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun int fd[2];
48*4882a593Smuzhiyun char _ = 0;
49*4882a593Smuzhiyun int nsfd;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun atexit(f);
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun /* Check for priviledges and syscall availability straight away. */
54*4882a593Smuzhiyun if (unshare(CLONE_NEWNET) == -1) {
55*4882a593Smuzhiyun if (errno == ENOSYS || errno == EPERM) {
56*4882a593Smuzhiyun return 4;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun return 1;
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun /* Distinguisher between two otherwise empty net namespaces. */
61*4882a593Smuzhiyun if (socket(AF_UNIX, SOCK_STREAM, 0) == -1) {
62*4882a593Smuzhiyun return 1;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun if (pipe(fd) == -1) {
66*4882a593Smuzhiyun return 1;
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun pid = fork();
70*4882a593Smuzhiyun if (pid == -1) {
71*4882a593Smuzhiyun return 1;
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun if (pid == 0) {
75*4882a593Smuzhiyun if (unshare(CLONE_NEWNET) == -1) {
76*4882a593Smuzhiyun return 1;
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun if (write(fd[1], &_, 1) != 1) {
80*4882a593Smuzhiyun return 1;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun pause();
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun return 0;
86*4882a593Smuzhiyun }
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun if (read(fd[0], &_, 1) != 1) {
89*4882a593Smuzhiyun return 1;
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun {
93*4882a593Smuzhiyun char buf[64];
94*4882a593Smuzhiyun snprintf(buf, sizeof(buf), "/proc/%u/ns/net", pid);
95*4882a593Smuzhiyun nsfd = open(buf, O_RDONLY);
96*4882a593Smuzhiyun if (nsfd == -1) {
97*4882a593Smuzhiyun return 1;
98*4882a593Smuzhiyun }
99*4882a593Smuzhiyun }
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun /* Reliably pin dentry into dcache. */
102*4882a593Smuzhiyun (void)open("/proc/net/unix", O_RDONLY);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun if (setns(nsfd, CLONE_NEWNET) == -1) {
105*4882a593Smuzhiyun return 1;
106*4882a593Smuzhiyun }
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun kill(pid, SIGTERM);
109*4882a593Smuzhiyun pid = 0;
110*4882a593Smuzhiyun
111*4882a593Smuzhiyun {
112*4882a593Smuzhiyun char buf[4096];
113*4882a593Smuzhiyun ssize_t rv;
114*4882a593Smuzhiyun int fd;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun fd = open("/proc/net/unix", O_RDONLY);
117*4882a593Smuzhiyun if (fd == -1) {
118*4882a593Smuzhiyun return 1;
119*4882a593Smuzhiyun }
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun #define S "Num RefCount Protocol Flags Type St Inode Path\n"
122*4882a593Smuzhiyun rv = read(fd, buf, sizeof(buf));
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun assert(rv == strlen(S));
125*4882a593Smuzhiyun assert(memcmp(buf, S, strlen(S)) == 0);
126*4882a593Smuzhiyun }
127*4882a593Smuzhiyun
128*4882a593Smuzhiyun return 0;
129*4882a593Smuzhiyun }
130