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