| 1 | |
| 2 | * Copyright (c) 2021 Alexey Dobriyan <[email protected]>
|
| 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 | }
|