src/util.rs

   1 #![allow(dead_code)]
   2
   3 use std::future::Future;
   4 use std::io;
   5 use std::pin::Pin;
   6 use std::task::{Context, Poll};
   7
   8 // from /usr/include/linux/magic.h
   9 // and from casync util.h
  10 #[rustfmt::skip]
  11 #[allow(clippy::unreadable_literal)]
  12 mod consts {
  13     pub const BINFMTFS_MAGIC      : i64 = 0x42494e4d;
  14     pub const CGROUP2_SUPER_MAGIC : i64 = 0x63677270;
  15     pub const CGROUP_SUPER_MAGIC  : i64 = 0x0027e0eb;
  16     pub const CONFIGFS_MAGIC      : i64 = 0x62656570;
  17     pub const DEBUGFS_MAGIC       : i64 = 0x64626720;
  18     pub const DEVPTS_SUPER_MAGIC  : i64 = 0x00001cd1;
  19     pub const EFIVARFS_MAGIC      : i64 = 0xde5e81e4;
  20     pub const FUSE_CTL_SUPER_MAGIC: i64 = 0x65735543;
  21     pub const HUGETLBFS_MAGIC     : i64 = 0x958458f6;
  22     pub const MQUEUE_MAGIC        : i64 = 0x19800202;
  23     pub const NFSD_MAGIC          : i64 = 0x6e667364;
  24     pub const PROC_SUPER_MAGIC    : i64 = 0x00009fa0;
  25     pub const PSTOREFS_MAGIC      : i64 = 0x6165676C;
  26     pub const RPCAUTH_GSSMAGIC    : i64 = 0x67596969;
  27     pub const SECURITYFS_MAGIC    : i64 = 0x73636673;
  28     pub const SELINUX_MAGIC       : i64 = 0xf97cff8c;
  29     pub const SMACK_MAGIC         : i64 = 0x43415d53;
  30     pub const RAMFS_MAGIC         : i64 = 0x858458f6;
  31     pub const TMPFS_MAGIC         : i64 = 0x01021994;
  32     pub const SYSFS_MAGIC         : i64 = 0x62656572;
  33     pub const MSDOS_SUPER_MAGIC   : i64 = 0x00004d44;
  34     pub const BTRFS_SUPER_MAGIC   : i64 = 0x9123683E;
  35     pub const FUSE_SUPER_MAGIC    : i64 = 0x65735546;
  36     pub const EXT4_SUPER_MAGIC    : i64 = 0x0000EF53;
  37     pub const XFS_SUPER_MAGIC     : i64 = 0x58465342;
  38     pub const ZFS_SUPER_MAGIC     : i64 = 0x2FC12FC1;
  39 }
  40
  41 pub fn is_virtual_file_system(magic: i64) -> bool {
  42     match magic {
  43         consts::BINFMTFS_MAGIC
  44         | consts::CGROUP2_SUPER_MAGIC
  45         | consts::CGROUP_SUPER_MAGIC
  46         | consts::CONFIGFS_MAGIC
  47         | consts::DEBUGFS_MAGIC
  48         | consts::DEVPTS_SUPER_MAGIC
  49         | consts::EFIVARFS_MAGIC
  50         | consts::FUSE_CTL_SUPER_MAGIC
  51         | consts::HUGETLBFS_MAGIC
  52         | consts::MQUEUE_MAGIC
  53         | consts::NFSD_MAGIC
  54         | consts::PROC_SUPER_MAGIC
  55         | consts::PSTOREFS_MAGIC
  56         | consts::RPCAUTH_GSSMAGIC
  57         | consts::SECURITYFS_MAGIC
  58         | consts::SELINUX_MAGIC
  59         | consts::SMACK_MAGIC
  60         | consts::SYSFS_MAGIC => true,
  61         _ => false,
  62     }
  63 }
  64
  65 /// Helper function to extract file names from binary archive.
  66 pub fn read_os_string(buffer: &[u8]) -> std::ffi::OsString {
  67     use std::os::unix::ffi::OsStrExt;
  68     std::ffi::OsStr::from_bytes(if buffer.ends_with(&[0]) {
  69         &buffer[..(buffer.len() - 1)]
  70     } else {
  71         buffer
  72     })
  73     .into()
  74 }
  75
  76 #[inline]
  77 pub fn vec_new(size: usize) -> Vec<u8> {
  78     let mut data = Vec::with_capacity(size);
  79     unsafe {
  80         data.set_len(size);
  81     }
  82     data
  83 }
  84
  85 pub fn io_err_other<E: std::fmt::Display>(err: E) -> io::Error {
  86     io::Error::new(io::ErrorKind::Other, err.to_string())
  87 }
  88
  89 pub fn poll_result_once<T, R>(mut fut: T) -> io::Result<R>
  90 where
  91     T: Future<Output = io::Result<R>>,
  92 {
  93     let waker = std::task::RawWaker::new(std::ptr::null(), &WAKER_VTABLE);
  94     let waker = unsafe { std::task::Waker::from_raw(waker) };
  95     let mut cx = Context::from_waker(&waker);
  96     unsafe {
  97         match Pin::new_unchecked(&mut fut).poll(&mut cx) {
  98             Poll::Pending => Err(io_err_other("got Poll::Pending synchronous context")),
  99             Poll::Ready(r) => r,
 100         }
 101     }
 102 }
 103
 104 const WAKER_VTABLE: std::task::RawWakerVTable =
 105     std::task::RawWakerVTable::new(forbid_clone, forbid_wake, forbid_wake, ignore_drop);
 106
 107 unsafe fn forbid_clone(_: *const ()) -> std::task::RawWaker {
 108     panic!("tried to clone waker for synchronous task");
 109 }
 110
 111 unsafe fn forbid_wake(_: *const ()) {
 112     panic!("tried to wake synchronous task");
 113 }
 114
 115 unsafe fn ignore_drop(_: *const ()) {}
 116
 117 pub fn validate_filename(name: &[u8]) -> io::Result<()> {
 118     if name.is_empty() {
 119         io_bail!("illegal path found (empty)");
 120     }
 121
 122     if name.contains(&b'/') {
 123         io_bail!("illegal path found (contains slashes, this is a security concern)");
 124     }
 125
 126     if name == b"." {
 127         io_bail!("illegal path found: '.'");
 128     }
 129
 130     if name == b".." {
 131         io_bail!("illegal path found: '..'");
 132     }
 133
 134     Ok(())
 135 }