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1 | /* |
2 | * Copyright (c) 2021 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 "mount -t proc -o subset=pid" hides everything but pids, | |
18 | * /proc/self and /proc/thread-self. | |
19 | */ | |
20 | #undef NDEBUG | |
21 | #include <assert.h> | |
22 | #include <errno.h> | |
23 | #include <sched.h> | |
24 | #include <stdbool.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <sys/mount.h> | |
28 | #include <sys/types.h> | |
29 | #include <sys/stat.h> | |
30 | #include <fcntl.h> | |
31 | #include <dirent.h> | |
32 | #include <unistd.h> | |
33 | #include <stdio.h> | |
34 | ||
35 | static inline bool streq(const char *a, const char *b) | |
36 | { | |
37 | return strcmp(a, b) == 0; | |
38 | } | |
39 | ||
40 | static void make_private_proc(void) | |
41 | { | |
42 | if (unshare(CLONE_NEWNS) == -1) { | |
43 | if (errno == ENOSYS || errno == EPERM) { | |
44 | exit(4); | |
45 | } | |
46 | exit(1); | |
47 | } | |
48 | if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) { | |
49 | exit(1); | |
50 | } | |
51 | if (mount(NULL, "/proc", "proc", 0, "subset=pid") == -1) { | |
52 | exit(1); | |
53 | } | |
54 | } | |
55 | ||
56 | static bool string_is_pid(const char *s) | |
57 | { | |
58 | while (1) { | |
59 | switch (*s++) { | |
60 | case '0':case '1':case '2':case '3':case '4': | |
61 | case '5':case '6':case '7':case '8':case '9': | |
62 | continue; | |
63 | ||
64 | case '\0': | |
65 | return true; | |
66 | ||
67 | default: | |
68 | return false; | |
69 | } | |
70 | } | |
71 | } | |
72 | ||
73 | int main(void) | |
74 | { | |
75 | make_private_proc(); | |
76 | ||
77 | DIR *d = opendir("/proc"); | |
78 | assert(d); | |
79 | ||
80 | struct dirent *de; | |
81 | ||
82 | bool dot = false; | |
83 | bool dot_dot = false; | |
84 | bool self = false; | |
85 | bool thread_self = false; | |
86 | ||
87 | while ((de = readdir(d))) { | |
88 | if (streq(de->d_name, ".")) { | |
89 | assert(!dot); | |
90 | dot = true; | |
91 | assert(de->d_type == DT_DIR); | |
92 | } else if (streq(de->d_name, "..")) { | |
93 | assert(!dot_dot); | |
94 | dot_dot = true; | |
95 | assert(de->d_type == DT_DIR); | |
96 | } else if (streq(de->d_name, "self")) { | |
97 | assert(!self); | |
98 | self = true; | |
99 | assert(de->d_type == DT_LNK); | |
100 | } else if (streq(de->d_name, "thread-self")) { | |
101 | assert(!thread_self); | |
102 | thread_self = true; | |
103 | assert(de->d_type == DT_LNK); | |
104 | } else { | |
105 | if (!string_is_pid(de->d_name)) { | |
106 | fprintf(stderr, "d_name '%s'\n", de->d_name); | |
107 | assert(0); | |
108 | } | |
109 | assert(de->d_type == DT_DIR); | |
110 | } | |
111 | } | |
112 | ||
113 | char c; | |
114 | int rv = readlink("/proc/cpuinfo", &c, 1); | |
115 | assert(rv == -1 && errno == ENOENT); | |
116 | ||
117 | int fd = open("/proc/cpuinfo", O_RDONLY); | |
118 | assert(fd == -1 && errno == ENOENT); | |
119 | ||
120 | return 0; | |
121 | } |