mft 0.9.1

A Fast (and safe) parser for the Windows Master File Table (MFT) format
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212

use crate::Utf16LeStr;
use crate::attribute::FileAttributeFlags;
use crate::err::{Error, Result};
use crate::utils::{read_u64, windows_filetime_to_timestamp};
use log::trace;

use byteorder::{LittleEndian, ReadBytesExt};
use jiff::Timestamp;
use num_traits::FromPrimitive;
use serde::Serialize;
use std::io::Cursor;

use winstructs::ntfs::mft_reference::MftReference;

#[derive(FromPrimitive, Serialize, Clone, Copy, Debug, PartialOrd, PartialEq)]
#[repr(u8)]
pub enum FileNamespace {
    POSIX = 0,
    Win32 = 1,
    DOS = 2,
    Win32AndDos = 3,
}

impl FileNamespace {
    /// Whether a name in this namespace is more than an 8.3 short name.
    pub(crate) fn is_long(self) -> bool {
        self != FileNamespace::DOS
    }
}

#[derive(Serialize, Clone, Debug, PartialEq)]
pub struct FileNameAttr<'a> {
    pub parent: MftReference,
    #[serde(serialize_with = "crate::utils::serialize_timestamp")]
    pub created: Timestamp,
    #[serde(serialize_with = "crate::utils::serialize_timestamp")]
    pub modified: Timestamp,
    #[serde(serialize_with = "crate::utils::serialize_timestamp")]
    pub mft_modified: Timestamp,
    #[serde(serialize_with = "crate::utils::serialize_timestamp")]
    pub accessed: Timestamp,
    /// The file's real (logical) size, as of the last time this name was updated.
    pub logical_size: u64,
    /// The size allocated on disk, as of the last time this name was updated.
    pub physical_size: u64,
    pub flags: FileAttributeFlags,
    pub reparse_value: u32,
    pub name_length: u8,
    pub namespace: FileNamespace,
    pub name: Utf16LeStr<'a>,
}

impl<'a> FileNameAttr<'a> {
    /// Parse a Filename attrbiute buffer.
    ///
    /// # Example
    ///
    /// Parse a raw buffer.
    ///
    /// ```
    /// use mft::attribute::x30::{FileNameAttr, FileNamespace};
    /// # use std::io::Cursor;
    /// let attribute_buffer: &[u8] = &[
    ///     0x05,0x00,0x00,0x00,0x00,0x00,0x05,0x00,0xD5,0x2D,0x48,0x58,0x43,0x5F,0xCE,0x01,
    ///     0xD5,0x2D,0x48,0x58,0x43,0x5F,0xCE,0x01,0xD5,0x2D,0x48,0x58,0x43,0x5F,0xCE,0x01,
    ///     0xD5,0x2D,0x48,0x58,0x43,0x5F,0xCE,0x01,0x00,0x00,0x00,0x04,0x00,0x00,0x00,0x00,
    ///     0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x00,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    ///     0x08,0x03,0x24,0x00,0x4C,0x00,0x6F,0x00,0x67,0x00,0x46,0x00,0x69,0x00,0x6C,0x00,
    ///     0x65,0x00,0x00,0x00,0x00,0x00,0x00,0x00
    /// ];
    ///
    /// let attribute = FileNameAttr::from_slice(attribute_buffer).unwrap();
    ///
    /// assert_eq!(attribute.parent.entry, 5);
    /// assert_eq!(attribute.created.as_second(), 1370144608);
    /// assert_eq!(attribute.modified.as_second(), 1370144608);
    /// assert_eq!(attribute.mft_modified.as_second(), 1370144608);
    /// assert_eq!(attribute.accessed.as_second(), 1370144608);
    /// // Allocated size (0x28) and real size (0x30) differ, so a swap would be caught here.
    /// assert_eq!(attribute.logical_size, 50331648);
    /// assert_eq!(attribute.physical_size, 67108864);
    /// assert_eq!(attribute.flags.bits(), 6);
    /// assert_eq!(attribute.reparse_value, 0);
    /// assert_eq!(attribute.name_length, 8);
    /// assert_eq!(attribute.namespace, FileNamespace::Win32AndDos);
    /// assert_eq!(attribute.name.to_utf8_string(), "$LogFile");
    /// ```
    pub fn from_slice(value: &'a [u8]) -> Result<FileNameAttr<'a>> {
        let mut stream = Cursor::new(value);
        trace!("Offset {}: FilenameAttr", stream.position());

        let parent =
            MftReference::from_reader(&mut stream).map_err(Error::failed_to_read_mft_reference)?;
        // Timestamps are stored as Windows FILETIME (100ns since 1601-01-01 UTC).
        let created =
            crate::utils::windows_filetime_to_timestamp(stream.read_u64::<LittleEndian>()?)?;
        let modified =
            crate::utils::windows_filetime_to_timestamp(stream.read_u64::<LittleEndian>()?)?;
        let mft_modified =
            crate::utils::windows_filetime_to_timestamp(stream.read_u64::<LittleEndian>()?)?;
        let accessed =
            crate::utils::windows_filetime_to_timestamp(stream.read_u64::<LittleEndian>()?)?;

        // The allocated size comes first (0x28), then the real size (0x30).
        let physical_size = stream.read_u64::<LittleEndian>()?;
        let logical_size = stream.read_u64::<LittleEndian>()?;
        let flags = FileAttributeFlags::from_bits_retain(stream.read_u32::<LittleEndian>()?);
        let reparse_value = stream.read_u32::<LittleEndian>()?;
        let name_length = stream.read_u8()?;
        let namespace = stream.read_u8()?;
        let namespace =
            FileNamespace::from_u8(namespace).ok_or(Error::UnknownNamespace { namespace })?;

        let name_pos = stream.position() as usize;
        let name_len_bytes = name_length as usize * 2;
        let name_bytes = value
            .get(name_pos..name_pos + name_len_bytes)
            .ok_or(Error::InvalidFilename)?;
        let name = Utf16LeStr::from_utf16le_bytes(name_bytes);

        Ok(FileNameAttr {
            parent,
            created,
            modified,
            mft_modified,
            accessed,
            logical_size,
            physical_size,
            flags,
            reparse_value,
            name_length,
            namespace,
            name,
        })
    }
}

/// The parts of a `$FILE_NAME` that path resolution needs: the name, and the entry number of the
/// directory it is in.
#[derive(Clone, Copy, Debug)]
pub(crate) struct NameInParent<'a> {
    pub(crate) parent: u64,
    pub(crate) namespace: FileNamespace,
    pub(crate) name: Utf16LeStr<'a>,
}

impl<'a> NameInParent<'a> {
    /// Reads the name and parent of a `$FILE_NAME` value, skipping its sizes and flags. Accepts
    /// exactly the values [`FileNameAttr::from_slice`] accepts, so that paths and parsed attributes
    /// agree on an entry's best name.
    pub(crate) fn from_slice(value: &'a [u8]) -> Option<NameInParent<'a>> {
        // `FileNameAttr::from_slice` rejects a timestamp out of range.
        let timestamps_valid = (0x08..0x28).step_by(8).all(|offset| {
            read_u64(value, offset)
                .is_some_and(|filetime| windows_filetime_to_timestamp(filetime).is_ok())
        });
        if !timestamps_valid {
            return None;
        }

        // The name follows the fixed fields, the last of which are its length and namespace.
        let name_length = usize::from(*value.get(0x40)?);
        let namespace = FileNamespace::from_u8(*value.get(0x41)?)?;
        let name = value.get(0x42..0x42 + name_length * 2)?;
        Some(NameInParent {
            parent: MftReference::from(read_u64(value, 0)?).entry,
            namespace,
            name: Utf16LeStr::from_utf16le_bytes(name),
        })
    }
}

#[cfg(test)]
mod tests {
    use super::{FileNameAttr, FileNamespace, NameInParent};
    use crate::entry::tests::filename_value_bytes;

    #[test]
    fn name_in_parent_accepts_what_file_name_attr_accepts() {
        let assert_agree = |value: &[u8]| {
            let name = NameInParent::from_slice(value).map(|n| (n.parent, n.namespace, n.name));
            let full = FileNameAttr::from_slice(value)
                .ok()
                .map(|f| (f.parent.entry, f.namespace, f.name));
            assert_eq!(name, full, "value {value:02X?}");
        };

        let log_file = filename_value_bytes("$LogFile", FileNamespace::Win32AndDos);
        assert!(NameInParent::from_slice(&log_file).is_some());
        for len in 0..=log_file.len() {
            assert_agree(&log_file[..len]);
        }
        // Covers out-of-range timestamps, overlong names and unknown namespaces.
        for position in 0..log_file.len() {
            for byte in [0x00, 0x01, 0x04, 0x7F, 0x80, 0xFF] {
                let mut value = log_file.clone();
                value[position] = byte;
                assert_agree(&value);
            }
        }
    }

    #[test]
    fn flags_keep_unknown_bits() {
        let mut value = vec![0u8; 66];
        value[0x38..0x3C].copy_from_slice(&0x8000_0006u32.to_le_bytes());

        let attr = FileNameAttr::from_slice(&value).unwrap();

        assert_eq!(attr.flags.bits(), 0x8000_0006);
    }
}