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
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
/*
* Copyright © 2019 Alexey Dobriyan <adobriyan@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Test that setns(CLONE_NEWNET) points to new /proc/net content even
* if old one is in dcache.
*
* FIXME /proc/net/unix is under CONFIG_UNIX which can be disabled.
*/
#undef NDEBUG
#include <assert.h>
#include <errno.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/socket.h>
static pid_t pid = -1;
static void f(void)
{
if (pid > 0) {
kill(pid, SIGTERM);
}
}
int main(void)
{
int fd[2];
char _ = 0;
int nsfd;
atexit(f);
/* Check for priviledges and syscall availability straight away. */
if (unshare(CLONE_NEWNET) == -1) {
if (errno == ENOSYS || errno == EPERM) {
return 4;
}
return 1;
}
/* Distinguisher between two otherwise empty net namespaces. */
if (socket(AF_UNIX, SOCK_STREAM, 0) == -1) {
return 1;
}
if (pipe(fd) == -1) {
return 1;
}
pid = fork();
if (pid == -1) {
return 1;
}
if (pid == 0) {
if (unshare(CLONE_NEWNET) == -1) {
return 1;
}
if (write(fd[1], &_, 1) != 1) {
return 1;
}
pause();
return 0;
}
if (read(fd[0], &_, 1) != 1) {
return 1;
}
{
char buf[64];
snprintf(buf, sizeof(buf), "/proc/%u/ns/net", pid);
nsfd = open(buf, O_RDONLY);
if (nsfd == -1) {
return 1;
}
}
/* Reliably pin dentry into dcache. */
(void)open("/proc/net/unix", O_RDONLY);
if (setns(nsfd, CLONE_NEWNET) == -1) {
return 1;
}
kill(pid, SIGTERM);
pid = 0;
{
char buf[4096];
ssize_t rv;
int fd;
fd = open("/proc/net/unix", O_RDONLY);
if (fd == -1) {
return 1;
}
#define S "Num RefCount Protocol Flags Type St Inode Path\n"
rv = read(fd, buf, sizeof(buf));
assert(rv == strlen(S));
assert(memcmp(buf, S, strlen(S)) == 0);
}
return 0;
}
|
