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The coccinelle report ./tools/testing/selftests/mount/unprivileged-remount-test.c:285:54-59: WARNING: conversion to bool not needed here ./tools/testing/selftests/mount/unprivileged-remount-test.c:207:54-59: WARNING: conversion to bool not needed here Relational and logical operators evaluate to bool, explicit conversion is overly verbose and unneeded. Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Yang Guang <yang.guang5@zte.com.cn> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
372 lines
8.2 KiB
C
372 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <sched.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/mount.h>
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#include <sys/wait.h>
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#include <sys/vfs.h>
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#include <sys/statvfs.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <grp.h>
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#include <stdbool.h>
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#include <stdarg.h>
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#ifndef CLONE_NEWNS
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# define CLONE_NEWNS 0x00020000
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#endif
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#ifndef CLONE_NEWUTS
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# define CLONE_NEWUTS 0x04000000
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#endif
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#ifndef CLONE_NEWIPC
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# define CLONE_NEWIPC 0x08000000
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#endif
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#ifndef CLONE_NEWNET
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# define CLONE_NEWNET 0x40000000
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#endif
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#ifndef CLONE_NEWUSER
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# define CLONE_NEWUSER 0x10000000
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#endif
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#ifndef CLONE_NEWPID
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# define CLONE_NEWPID 0x20000000
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#endif
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#ifndef MS_REC
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# define MS_REC 16384
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#endif
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#ifndef MS_RELATIME
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# define MS_RELATIME (1 << 21)
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#endif
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#ifndef MS_STRICTATIME
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# define MS_STRICTATIME (1 << 24)
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#endif
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static void die(char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vfprintf(stderr, fmt, ap);
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va_end(ap);
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exit(EXIT_FAILURE);
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}
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static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)
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{
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char buf[4096];
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int fd;
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ssize_t written;
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int buf_len;
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buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
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if (buf_len < 0) {
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die("vsnprintf failed: %s\n",
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strerror(errno));
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}
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if (buf_len >= sizeof(buf)) {
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die("vsnprintf output truncated\n");
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}
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fd = open(filename, O_WRONLY);
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if (fd < 0) {
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if ((errno == ENOENT) && enoent_ok)
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return;
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die("open of %s failed: %s\n",
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filename, strerror(errno));
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}
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written = write(fd, buf, buf_len);
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if (written != buf_len) {
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if (written >= 0) {
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die("short write to %s\n", filename);
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} else {
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die("write to %s failed: %s\n",
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filename, strerror(errno));
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}
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}
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if (close(fd) != 0) {
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die("close of %s failed: %s\n",
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filename, strerror(errno));
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}
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}
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static void maybe_write_file(char *filename, char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vmaybe_write_file(true, filename, fmt, ap);
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va_end(ap);
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}
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static void write_file(char *filename, char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vmaybe_write_file(false, filename, fmt, ap);
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va_end(ap);
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}
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static int read_mnt_flags(const char *path)
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{
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int ret;
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struct statvfs stat;
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int mnt_flags;
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ret = statvfs(path, &stat);
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if (ret != 0) {
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die("statvfs of %s failed: %s\n",
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path, strerror(errno));
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}
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if (stat.f_flag & ~(ST_RDONLY | ST_NOSUID | ST_NODEV | \
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ST_NOEXEC | ST_NOATIME | ST_NODIRATIME | ST_RELATIME | \
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ST_SYNCHRONOUS | ST_MANDLOCK)) {
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die("Unrecognized mount flags\n");
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}
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mnt_flags = 0;
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if (stat.f_flag & ST_RDONLY)
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mnt_flags |= MS_RDONLY;
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if (stat.f_flag & ST_NOSUID)
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mnt_flags |= MS_NOSUID;
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if (stat.f_flag & ST_NODEV)
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mnt_flags |= MS_NODEV;
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if (stat.f_flag & ST_NOEXEC)
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mnt_flags |= MS_NOEXEC;
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if (stat.f_flag & ST_NOATIME)
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mnt_flags |= MS_NOATIME;
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if (stat.f_flag & ST_NODIRATIME)
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mnt_flags |= MS_NODIRATIME;
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if (stat.f_flag & ST_RELATIME)
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mnt_flags |= MS_RELATIME;
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if (stat.f_flag & ST_SYNCHRONOUS)
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mnt_flags |= MS_SYNCHRONOUS;
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if (stat.f_flag & ST_MANDLOCK)
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mnt_flags |= ST_MANDLOCK;
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return mnt_flags;
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}
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static void create_and_enter_userns(void)
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{
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uid_t uid;
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gid_t gid;
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uid = getuid();
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gid = getgid();
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if (unshare(CLONE_NEWUSER) !=0) {
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die("unshare(CLONE_NEWUSER) failed: %s\n",
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strerror(errno));
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}
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maybe_write_file("/proc/self/setgroups", "deny");
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write_file("/proc/self/uid_map", "0 %d 1", uid);
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write_file("/proc/self/gid_map", "0 %d 1", gid);
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if (setgid(0) != 0) {
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die ("setgid(0) failed %s\n",
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strerror(errno));
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}
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if (setuid(0) != 0) {
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die("setuid(0) failed %s\n",
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strerror(errno));
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}
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}
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static
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bool test_unpriv_remount(const char *fstype, const char *mount_options,
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int mount_flags, int remount_flags, int invalid_flags)
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{
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pid_t child;
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child = fork();
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if (child == -1) {
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die("fork failed: %s\n",
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strerror(errno));
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}
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if (child != 0) { /* parent */
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pid_t pid;
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int status;
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pid = waitpid(child, &status, 0);
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if (pid == -1) {
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die("waitpid failed: %s\n",
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strerror(errno));
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}
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if (pid != child) {
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die("waited for %d got %d\n",
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child, pid);
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}
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if (!WIFEXITED(status)) {
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die("child did not terminate cleanly\n");
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}
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return WEXITSTATUS(status) == EXIT_SUCCESS;
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}
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create_and_enter_userns();
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if (unshare(CLONE_NEWNS) != 0) {
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die("unshare(CLONE_NEWNS) failed: %s\n",
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strerror(errno));
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}
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if (mount("testing", "/tmp", fstype, mount_flags, mount_options) != 0) {
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die("mount of %s with options '%s' on /tmp failed: %s\n",
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fstype,
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mount_options? mount_options : "",
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strerror(errno));
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}
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create_and_enter_userns();
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if (unshare(CLONE_NEWNS) != 0) {
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die("unshare(CLONE_NEWNS) failed: %s\n",
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strerror(errno));
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}
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if (mount("/tmp", "/tmp", "none",
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MS_REMOUNT | MS_BIND | remount_flags, NULL) != 0) {
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/* system("cat /proc/self/mounts"); */
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die("remount of /tmp failed: %s\n",
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strerror(errno));
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}
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if (mount("/tmp", "/tmp", "none",
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MS_REMOUNT | MS_BIND | invalid_flags, NULL) == 0) {
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/* system("cat /proc/self/mounts"); */
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die("remount of /tmp with invalid flags "
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"succeeded unexpectedly\n");
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}
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exit(EXIT_SUCCESS);
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}
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static bool test_unpriv_remount_simple(int mount_flags)
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{
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return test_unpriv_remount("ramfs", NULL, mount_flags, mount_flags, 0);
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}
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static bool test_unpriv_remount_atime(int mount_flags, int invalid_flags)
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{
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return test_unpriv_remount("ramfs", NULL, mount_flags, mount_flags,
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invalid_flags);
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}
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static bool test_priv_mount_unpriv_remount(void)
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{
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pid_t child;
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int ret;
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const char *orig_path = "/dev";
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const char *dest_path = "/tmp";
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int orig_mnt_flags, remount_mnt_flags;
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child = fork();
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if (child == -1) {
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die("fork failed: %s\n",
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strerror(errno));
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}
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if (child != 0) { /* parent */
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pid_t pid;
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int status;
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pid = waitpid(child, &status, 0);
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if (pid == -1) {
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die("waitpid failed: %s\n",
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strerror(errno));
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}
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if (pid != child) {
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die("waited for %d got %d\n",
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child, pid);
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}
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if (!WIFEXITED(status)) {
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die("child did not terminate cleanly\n");
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}
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return WEXITSTATUS(status) == EXIT_SUCCESS;
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}
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orig_mnt_flags = read_mnt_flags(orig_path);
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create_and_enter_userns();
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ret = unshare(CLONE_NEWNS);
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if (ret != 0) {
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die("unshare(CLONE_NEWNS) failed: %s\n",
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strerror(errno));
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}
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ret = mount(orig_path, dest_path, "bind", MS_BIND | MS_REC, NULL);
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if (ret != 0) {
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die("recursive bind mount of %s onto %s failed: %s\n",
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orig_path, dest_path, strerror(errno));
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}
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ret = mount(dest_path, dest_path, "none",
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MS_REMOUNT | MS_BIND | orig_mnt_flags , NULL);
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if (ret != 0) {
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/* system("cat /proc/self/mounts"); */
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die("remount of /tmp failed: %s\n",
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strerror(errno));
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}
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remount_mnt_flags = read_mnt_flags(dest_path);
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if (orig_mnt_flags != remount_mnt_flags) {
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die("Mount flags unexpectedly changed during remount of %s originally mounted on %s\n",
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dest_path, orig_path);
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}
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exit(EXIT_SUCCESS);
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}
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int main(int argc, char **argv)
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{
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if (!test_unpriv_remount_simple(MS_RDONLY)) {
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die("MS_RDONLY malfunctions\n");
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}
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if (!test_unpriv_remount("devpts", "newinstance", MS_NODEV, MS_NODEV, 0)) {
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die("MS_NODEV malfunctions\n");
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}
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if (!test_unpriv_remount_simple(MS_NOSUID)) {
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die("MS_NOSUID malfunctions\n");
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}
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if (!test_unpriv_remount_simple(MS_NOEXEC)) {
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die("MS_NOEXEC malfunctions\n");
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}
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if (!test_unpriv_remount_atime(MS_RELATIME,
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MS_NOATIME))
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{
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die("MS_RELATIME malfunctions\n");
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}
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if (!test_unpriv_remount_atime(MS_STRICTATIME,
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MS_NOATIME))
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{
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die("MS_STRICTATIME malfunctions\n");
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}
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if (!test_unpriv_remount_atime(MS_NOATIME,
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MS_STRICTATIME))
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{
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die("MS_NOATIME malfunctions\n");
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}
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if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODIRATIME,
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MS_NOATIME))
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{
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die("MS_RELATIME|MS_NODIRATIME malfunctions\n");
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}
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if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODIRATIME,
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MS_NOATIME))
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{
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die("MS_STRICTATIME|MS_NODIRATIME malfunctions\n");
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}
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if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODIRATIME,
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MS_STRICTATIME))
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{
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die("MS_NOATIME|MS_DIRATIME malfunctions\n");
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}
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if (!test_unpriv_remount("ramfs", NULL, MS_STRICTATIME, 0, MS_NOATIME))
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{
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die("Default atime malfunctions\n");
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}
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if (!test_priv_mount_unpriv_remount()) {
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die("Mount flags unexpectedly changed after remount\n");
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}
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return EXIT_SUCCESS;
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}
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