122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
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/*
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* Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Test that "mount -t proc -o subset=pid" hides everything but pids,
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* /proc/self and /proc/thread-self.
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*/
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#undef NDEBUG
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#include <assert.h>
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#include <errno.h>
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#include <sched.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mount.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <stdio.h>
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static inline bool streq(const char *a, const char *b)
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{
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return strcmp(a, b) == 0;
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}
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static void make_private_proc(void)
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{
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if (unshare(CLONE_NEWNS) == -1) {
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if (errno == ENOSYS || errno == EPERM) {
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exit(4);
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}
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exit(1);
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}
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if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
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exit(1);
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}
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if (mount(NULL, "/proc", "proc", 0, "subset=pid") == -1) {
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exit(1);
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}
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}
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static bool string_is_pid(const char *s)
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{
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while (1) {
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switch (*s++) {
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case '0':case '1':case '2':case '3':case '4':
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case '5':case '6':case '7':case '8':case '9':
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continue;
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case '\0':
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return true;
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default:
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return false;
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}
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}
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}
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int main(void)
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{
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make_private_proc();
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DIR *d = opendir("/proc");
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assert(d);
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struct dirent *de;
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bool dot = false;
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bool dot_dot = false;
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bool self = false;
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bool thread_self = false;
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while ((de = readdir(d))) {
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if (streq(de->d_name, ".")) {
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assert(!dot);
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dot = true;
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assert(de->d_type == DT_DIR);
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} else if (streq(de->d_name, "..")) {
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assert(!dot_dot);
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dot_dot = true;
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assert(de->d_type == DT_DIR);
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} else if (streq(de->d_name, "self")) {
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assert(!self);
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self = true;
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assert(de->d_type == DT_LNK);
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} else if (streq(de->d_name, "thread-self")) {
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assert(!thread_self);
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thread_self = true;
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assert(de->d_type == DT_LNK);
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} else {
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if (!string_is_pid(de->d_name)) {
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fprintf(stderr, "d_name '%s'\n", de->d_name);
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assert(0);
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}
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assert(de->d_type == DT_DIR);
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}
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}
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char c;
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int rv = readlink("/proc/cpuinfo", &c, 1);
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assert(rv == -1 && errno == ENOENT);
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int fd = open("/proc/cpuinfo", O_RDONLY);
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assert(fd == -1 && errno == ENOENT);
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return 0;
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}
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