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use std::fs::{self, File};
use std::io::{Read, Write};
use std::os::unix::fs::OpenOptionsExt;
use std::os::unix::fs::PermissionsExt;
use std::process::Command;
use libc::{EACCES, EROFS};
use nix::mount::{mount, umount, MsFlags};
use nix::sys::stat::{self, Mode};
use crate::*;
static SCRIPT_CONTENTS: &[u8] = b"#!/bin/sh
exit 23";
const EXPECTED_STATUS: i32 = 23;
const NONE: Option<&'static [u8]> = None;
#[test]
fn test_mount_tmpfs_without_flags_allows_rwx() {
require_capability!(
"test_mount_tmpfs_without_flags_allows_rwx",
CAP_SYS_ADMIN
);
let tempdir = tempfile::tempdir().unwrap();
mount(
NONE,
tempdir.path(),
Some(b"tmpfs".as_ref()),
MsFlags::empty(),
NONE,
)
.unwrap_or_else(|e| panic!("mount failed: {e}"));
let test_path = tempdir.path().join("test");
// Verify write.
fs::OpenOptions::new()
.create(true)
.write(true)
.mode((Mode::S_IRWXU | Mode::S_IRWXG | Mode::S_IRWXO).bits())
.open(&test_path)
.and_then(|mut f| f.write(SCRIPT_CONTENTS))
.unwrap_or_else(|e| panic!("write failed: {e}"));
// Verify read.
let mut buf = Vec::new();
File::open(&test_path)
.and_then(|mut f| f.read_to_end(&mut buf))
.unwrap_or_else(|e| panic!("read failed: {e}"));
assert_eq!(buf, SCRIPT_CONTENTS);
// while forking and unmounting prevent other child processes
let _m = FORK_MTX.lock();
// Verify execute.
assert_eq!(
EXPECTED_STATUS,
Command::new(&test_path)
.status()
.unwrap_or_else(|e| panic!("exec failed: {e}"))
.code()
.unwrap_or_else(|| panic!("child killed by signal"))
);
umount(tempdir.path()).unwrap_or_else(|e| panic!("umount failed: {e}"));
}
#[test]
fn test_mount_rdonly_disallows_write() {
require_capability!("test_mount_rdonly_disallows_write", CAP_SYS_ADMIN);
let tempdir = tempfile::tempdir().unwrap();
mount(
NONE,
tempdir.path(),
Some(b"tmpfs".as_ref()),
MsFlags::MS_RDONLY,
NONE,
)
.unwrap_or_else(|e| panic!("mount failed: {e}"));
// EROFS: Read-only file system
assert_eq!(
EROFS,
File::create(tempdir.path().join("test"))
.unwrap_err()
.raw_os_error()
.unwrap()
);
umount(tempdir.path()).unwrap_or_else(|e| panic!("umount failed: {e}"));
}
#[test]
fn test_mount_noexec_disallows_exec() {
require_capability!("test_mount_noexec_disallows_exec", CAP_SYS_ADMIN);
let tempdir = tempfile::tempdir().unwrap();
mount(
NONE,
tempdir.path(),
Some(b"tmpfs".as_ref()),
MsFlags::MS_NOEXEC,
NONE,
)
.unwrap_or_else(|e| panic!("mount failed: {e}"));
let test_path = tempdir.path().join("test");
fs::OpenOptions::new()
.create(true)
.write(true)
.mode((Mode::S_IRWXU | Mode::S_IRWXG | Mode::S_IRWXO).bits())
.open(&test_path)
.and_then(|mut f| f.write(SCRIPT_CONTENTS))
.unwrap_or_else(|e| panic!("write failed: {e}"));
// Verify that we cannot execute despite a+x permissions being set.
let mode = stat::Mode::from_bits_truncate(
fs::metadata(&test_path)
.map(|md| md.permissions().mode())
.unwrap_or_else(|e| panic!("metadata failed: {e}")),
);
assert!(
mode.contains(Mode::S_IXUSR | Mode::S_IXGRP | Mode::S_IXOTH),
"{:?} did not have execute permissions",
&test_path
);
// while forking and unmounting prevent other child processes
let _m = FORK_MTX.lock();
// EACCES: Permission denied
assert_eq!(
EACCES,
Command::new(&test_path)
.status()
.unwrap_err()
.raw_os_error()
.unwrap()
);
umount(tempdir.path()).unwrap_or_else(|e| panic!("umount failed: {e}"));
}
#[test]
fn test_mount_bind() {
require_capability!("test_mount_bind", CAP_SYS_ADMIN);
let tempdir = tempfile::tempdir().unwrap();
let file_name = "test";
{
let mount_point = tempfile::tempdir().unwrap();
mount(
Some(tempdir.path()),
mount_point.path(),
NONE,
MsFlags::MS_BIND,
NONE,
)
.unwrap_or_else(|e| panic!("mount failed: {e}"));
fs::OpenOptions::new()
.create(true)
.write(true)
.mode((Mode::S_IRWXU | Mode::S_IRWXG | Mode::S_IRWXO).bits())
.open(mount_point.path().join(file_name))
.and_then(|mut f| f.write(SCRIPT_CONTENTS))
.unwrap_or_else(|e| panic!("write failed: {e}"));
// wait for child processes to prevent EBUSY
let _m = FORK_MTX.lock();
umount(mount_point.path())
.unwrap_or_else(|e| panic!("umount failed: {e}"));
}
// Verify the file written in the mount shows up in source directory, even
// after unmounting.
let mut buf = Vec::new();
File::open(tempdir.path().join(file_name))
.and_then(|mut f| f.read_to_end(&mut buf))
.unwrap_or_else(|e| panic!("read failed: {e}"));
assert_eq!(buf, SCRIPT_CONTENTS);
}