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_NEWIPC) points to new /proc/sysvipc content even |
18 | * if old one is in dcache. |
19 | */ |
20 | #undef NDEBUG |
21 | #include <assert.h> |
22 | #include <errno.h> |
23 | #include <stdio.h> |
24 | #include <sched.h> |
25 | #include <signal.h> |
26 | #include <stdlib.h> |
27 | #include <string.h> |
28 | #include <unistd.h> |
29 | #include <sys/types.h> |
30 | #include <sys/stat.h> |
31 | #include <fcntl.h> |
32 | #include <sys/ipc.h> |
33 | #include <sys/shm.h> |
34 | |
35 | static pid_t pid = -1; |
36 | |
37 | static void f(void) |
38 | { |
39 | if (pid > 0) { |
40 | kill(pid, SIGTERM); |
41 | } |
42 | } |
43 | |
44 | int main(void) |
45 | { |
46 | int fd[2]; |
47 | char _ = 0; |
48 | int nsfd; |
49 | |
50 | atexit(f); |
51 | |
52 | /* Check for priviledges and syscall availability straight away. */ |
53 | if (unshare(CLONE_NEWIPC) == -1) { |
54 | if (errno == ENOSYS || errno == EPERM) { |
55 | return 4; |
56 | } |
57 | return 1; |
58 | } |
59 | /* Distinguisher between two otherwise empty IPC namespaces. */ |
60 | if (shmget(IPC_PRIVATE, 1, IPC_CREAT) == -1) { |
61 | return 1; |
62 | } |
63 | |
64 | if (pipe(fd) == -1) { |
65 | return 1; |
66 | } |
67 | |
68 | pid = fork(); |
69 | if (pid == -1) { |
70 | return 1; |
71 | } |
72 | |
73 | if (pid == 0) { |
74 | if (unshare(CLONE_NEWIPC) == -1) { |
75 | return 1; |
76 | } |
77 | |
78 | if (write(fd[1], &_, 1) != 1) { |
79 | return 1; |
80 | } |
81 | |
82 | pause(); |
83 | |
84 | return 0; |
85 | } |
86 | |
87 | if (read(fd[0], &_, 1) != 1) { |
88 | return 1; |
89 | } |
90 | |
91 | { |
92 | char buf[64]; |
93 | snprintf(buf, sizeof(buf), "/proc/%u/ns/ipc" , pid); |
94 | nsfd = open(buf, O_RDONLY); |
95 | if (nsfd == -1) { |
96 | return 1; |
97 | } |
98 | } |
99 | |
100 | /* Reliably pin dentry into dcache. */ |
101 | (void)open("/proc/sysvipc/shm" , O_RDONLY); |
102 | |
103 | if (setns(nsfd, CLONE_NEWIPC) == -1) { |
104 | return 1; |
105 | } |
106 | |
107 | kill(pid, SIGTERM); |
108 | pid = 0; |
109 | |
110 | { |
111 | char buf[4096]; |
112 | ssize_t rv; |
113 | int fd; |
114 | |
115 | fd = open("/proc/sysvipc/shm" , O_RDONLY); |
116 | if (fd == -1) { |
117 | return 1; |
118 | } |
119 | |
120 | #define S32 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n" |
121 | #define S64 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n" |
122 | rv = read(fd, buf, sizeof(buf)); |
123 | if (rv == strlen(S32)) { |
124 | assert(memcmp(buf, S32, strlen(S32)) == 0); |
125 | } else if (rv == strlen(S64)) { |
126 | assert(memcmp(buf, S64, strlen(S64)) == 0); |
127 | } else { |
128 | assert(0); |
129 | } |
130 | } |
131 | |
132 | return 0; |
133 | } |
134 | |