exhume_filesystem 0.5.2

This exhume module is proposing a standard abstraction layer of a FileSystem, File and Directory for any exhume filesystem modules (extfs, ...).
Documentation
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use crate::apfs_impl::ApfsFs;
use crate::filesystem::{DirectoryCommon, File, FileCommon, Filesystem};
use crate::folder_impl::FolderFS;
use exhume_apfs::APFS;
use exhume_body::{Body, BodySlice};
use exhume_exfat::ExFatFS;
use exhume_extfs::ExtFS;
use exhume_ntfs::NTFS;
use exhume_ntfs::bitlocker::BitLockerStream;
use log::info;
use serde_json::Value;
use std::error::Error;
use std::io::{self, Read, Seek, SeekFrom};

#[derive(Debug, Clone, Default)]
pub struct KeyMaterial {
    pub bitlocker_fvek: Option<Vec<u8>>,
}

pub enum ImageStream {
    Raw(BodySlice),
    BitLocker(BitLockerStream<BodySlice>),
}

impl Read for ImageStream {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        match self {
            ImageStream::Raw(slice) => slice.read(buf),
            ImageStream::BitLocker(bl) => bl.read(buf),
        }
    }
}

impl Seek for ImageStream {
    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
        match self {
            ImageStream::Raw(slice) => slice.seek(pos),
            ImageStream::BitLocker(bl) => bl.seek(pos),
        }
    }
}

#[allow(clippy::large_enum_variant)]
pub enum DetectedFs<T: Read + Seek> {
    Ext(ExtFS<T>),
    Ntfs(NTFS<T>),
    Exfat(ExFatFS<T>),
    Apfs(ApfsFs<T>),
    Folder(FolderFS),
}

pub enum DetectedFile {
    Ext(exhume_extfs::inode::Inode),
    Ntfs(exhume_ntfs::mft::MFTRecord),
    Exfat(exhume_exfat::exinode::ExInode),
    Apfs(crate::apfs_impl::ApfsFileRecord),
    Folder(crate::folder_impl::FolderFile),
}

pub enum DetectedDir {
    Ext(exhume_extfs::direntry::DirEntry),
    Ntfs(exhume_ntfs::mft::DirectoryEntry),
    Exfat(exhume_exfat::compat::CompatDirEntry),
    Apfs(crate::apfs_impl::ApfsDirectoryEntry),
    Folder(crate::folder_impl::FolderDirectory),
}

impl FileCommon for DetectedFile {
    fn id(&self) -> u64 {
        match self {
            DetectedFile::Ext(inode) => inode.id(),
            DetectedFile::Ntfs(record) => record.id(),
            DetectedFile::Exfat(inode) => inode.id(),
            DetectedFile::Apfs(inode) => inode.id(),
            DetectedFile::Folder(file) => file.id(),
        }
    }
    fn size(&self) -> u64 {
        match self {
            DetectedFile::Ext(inode) => inode.size(),
            DetectedFile::Ntfs(record) => record.size(),
            DetectedFile::Exfat(inode) => inode.size(),
            DetectedFile::Apfs(inode) => inode.size(),
            DetectedFile::Folder(file) => file.size(),
        }
    }
    fn is_dir(&self) -> bool {
        match self {
            DetectedFile::Ext(inode) => inode.is_dir(),
            DetectedFile::Ntfs(record) => record.is_dir(),
            DetectedFile::Exfat(inode) => inode.is_dir(),
            DetectedFile::Apfs(inode) => inode.is_dir(),
            DetectedFile::Folder(file) => file.is_dir(),
        }
    }
    fn to_string(&self) -> String {
        match self {
            DetectedFile::Ext(inode) => FileCommon::to_string(inode),
            DetectedFile::Ntfs(record) => FileCommon::to_string(record),
            DetectedFile::Exfat(inode) => FileCommon::to_string(inode),
            DetectedFile::Apfs(inode) => FileCommon::to_string(inode),
            DetectedFile::Folder(file) => FileCommon::to_string(file),
        }
    }
    fn to_json(&self) -> Value {
        match self {
            DetectedFile::Ext(inode) => inode.to_json(),
            DetectedFile::Ntfs(record) => record.to_json(),
            DetectedFile::Exfat(inode) => inode.to_json(),
            DetectedFile::Apfs(inode) => inode.to_json(),
            DetectedFile::Folder(file) => file.to_json(),
        }
    }
}

impl DirectoryCommon for DetectedDir {
    fn file_id(&self) -> u64 {
        match self {
            DetectedDir::Ext(d) => d.file_id(),
            DetectedDir::Ntfs(d) => d.file_id(),
            DetectedDir::Exfat(d) => d.file_id(),
            DetectedDir::Apfs(d) => d.file_id(),
            DetectedDir::Folder(d) => d.file_id(),
        }
    }
    fn name(&self) -> &str {
        match self {
            DetectedDir::Ext(d) => d.name(),
            DetectedDir::Ntfs(d) => d.name(),
            DetectedDir::Exfat(d) => d.name(),
            DetectedDir::Apfs(d) => d.name(),
            DetectedDir::Folder(d) => d.name(),
        }
    }
    fn to_string(&self) -> String {
        match self {
            DetectedDir::Ext(d) => DirectoryCommon::to_string(d),
            DetectedDir::Ntfs(d) => DirectoryCommon::to_string(d),
            DetectedDir::Exfat(d) => DirectoryCommon::to_string(d),
            DetectedDir::Apfs(d) => DirectoryCommon::to_string(d),
            DetectedDir::Folder(d) => DirectoryCommon::to_string(d),
        }
    }
    fn to_json(&self) -> Value {
        match self {
            DetectedDir::Ext(d) => d.to_json(),
            DetectedDir::Ntfs(d) => d.to_json(),
            DetectedDir::Exfat(d) => d.to_json(),
            DetectedDir::Apfs(d) => d.to_json(),
            DetectedDir::Folder(d) => d.to_json(),
        }
    }
}

impl<T: Read + Seek> Filesystem for DetectedFs<T> {
    type FileType = DetectedFile;
    type DirectoryType = DetectedDir;

    fn filesystem_type(&self) -> String {
        match self {
            DetectedFs::Ext(fs) => fs.filesystem_type(),
            DetectedFs::Ntfs(fs) => fs.filesystem_type(),
            DetectedFs::Exfat(fs) => fs.filesystem_type(),
            DetectedFs::Apfs(fs) => fs.filesystem_type(),
            DetectedFs::Folder(fs) => fs.filesystem_type(),
        }
    }
    fn path_separator(&self) -> String {
        match self {
            DetectedFs::Ext(fs) => fs.path_separator(),
            DetectedFs::Ntfs(fs) => fs.path_separator(),
            DetectedFs::Exfat(fs) => fs.path_separator(),
            DetectedFs::Apfs(fs) => fs.path_separator(),
            DetectedFs::Folder(fs) => fs.path_separator(),
        }
    }
    fn record_count(&mut self) -> u64 {
        match self {
            DetectedFs::Ext(fs) => fs.record_count(),
            DetectedFs::Ntfs(fs) => fs.record_count(),
            DetectedFs::Exfat(fs) => fs.record_count(),
            DetectedFs::Apfs(fs) => fs.record_count(),
            DetectedFs::Folder(fs) => fs.record_count(),
        }
    }
    fn block_size(&self) -> u64 {
        match self {
            DetectedFs::Ext(fs) => fs.block_size(),
            DetectedFs::Ntfs(fs) => fs.block_size(),
            DetectedFs::Exfat(fs) => fs.block_size(),
            DetectedFs::Apfs(fs) => fs.block_size(),
            DetectedFs::Folder(fs) => fs.block_size(),
        }
    }
    fn get_metadata(&self) -> Result<Value, Box<dyn Error>> {
        match self {
            DetectedFs::Ext(fs) => fs.get_metadata(),
            DetectedFs::Ntfs(fs) => fs.get_metadata(),
            DetectedFs::Exfat(fs) => fs.get_metadata(),
            DetectedFs::Apfs(fs) => fs.get_metadata(),
            DetectedFs::Folder(fs) => fs.get_metadata(),
        }
    }
    fn get_metadata_pretty(&self) -> Result<String, Box<dyn Error>> {
        match self {
            DetectedFs::Ext(fs) => fs.get_metadata_pretty(),
            DetectedFs::Ntfs(fs) => fs.get_metadata_pretty(),
            DetectedFs::Exfat(fs) => fs.get_metadata_pretty(),
            DetectedFs::Apfs(fs) => fs.get_metadata_pretty(),
            DetectedFs::Folder(fs) => fs.get_metadata_pretty(),
        }
    }
    fn get_file(&mut self, file_id: u64) -> Result<Self::FileType, Box<dyn Error>> {
        match self {
            DetectedFs::Ext(fs) => fs.get_file(file_id).map(DetectedFile::Ext),
            DetectedFs::Ntfs(fs) => fs.get_file(file_id).map(DetectedFile::Ntfs),
            DetectedFs::Exfat(fs) => fs.get_file(file_id).map(DetectedFile::Exfat),
            DetectedFs::Apfs(fs) => fs.get_file(file_id).map(DetectedFile::Apfs),
            DetectedFs::Folder(fs) => fs.get_file(file_id).map(DetectedFile::Folder),
        }
    }
    fn get_file_by_path(
        &mut self,
        path: &str,
        file_id: u64,
    ) -> Result<Self::FileType, Box<dyn Error>> {
        match self {
            DetectedFs::Ext(fs) => fs.get_file_by_path(path, file_id).map(DetectedFile::Ext),
            DetectedFs::Ntfs(fs) => fs.get_file_by_path(path, file_id).map(DetectedFile::Ntfs),
            DetectedFs::Exfat(fs) => fs.get_file_by_path(path, file_id).map(DetectedFile::Exfat),
            DetectedFs::Apfs(fs) => fs.get_file_by_path(path, file_id).map(DetectedFile::Apfs),
            DetectedFs::Folder(fs) => fs.get_file_by_path(path, file_id).map(DetectedFile::Folder),
        }
    }
    fn read_file_content(&mut self, record: &Self::FileType) -> Result<Vec<u8>, Box<dyn Error>> {
        match (self, record) {
            (DetectedFs::Ext(fs), DetectedFile::Ext(inode)) => fs.read_file_content(inode),
            (DetectedFs::Ntfs(fs), DetectedFile::Ntfs(rec)) => fs.read_file_content(rec),
            (DetectedFs::Exfat(fs), DetectedFile::Exfat(inode)) => fs.read_file_content(inode),
            (DetectedFs::Apfs(fs), DetectedFile::Apfs(inode)) => fs.read_file_content(inode),
            (DetectedFs::Folder(fs), DetectedFile::Folder(file)) => fs.read_file_content(file),
            _ => Err("filesystem / record variant mismatch".into()),
        }
    }
    fn read_file_prefix(
        &mut self,
        record: &Self::FileType,
        length: usize,
    ) -> Result<Vec<u8>, Box<dyn Error>> {
        match (self, record) {
            (DetectedFs::Ext(fs), DetectedFile::Ext(inode)) => fs.read_file_prefix(inode, length),
            (DetectedFs::Ntfs(fs), DetectedFile::Ntfs(rec)) => fs.read_file_prefix(rec, length),
            (DetectedFs::Exfat(fs), DetectedFile::Exfat(inode)) => {
                fs.read_file_prefix(inode, length)
            }

            (DetectedFs::Apfs(fs), DetectedFile::Apfs(inode)) => fs.read_file_prefix(inode, length),
            (DetectedFs::Folder(fs), DetectedFile::Folder(file)) => {
                fs.read_file_prefix(file, length)
            }
            _ => Err("filesystem / record variant mismatch".into()),
        }
    }
    fn read_file_slice(
        &mut self,
        record: &Self::FileType,
        offset: u64,
        length: usize,
    ) -> Result<Vec<u8>, Box<dyn Error>> {
        match (self, record) {
            (DetectedFs::Ext(fs), DetectedFile::Ext(inode)) => {
                fs.read_file_slice(inode, offset, length)
            }
            (DetectedFs::Ntfs(fs), DetectedFile::Ntfs(rec)) => {
                fs.read_file_slice(rec, offset, length)
            }
            (DetectedFs::Exfat(fs), DetectedFile::Exfat(inode)) => {
                fs.read_file_slice(inode, offset, length)
            }
            (DetectedFs::Apfs(fs), DetectedFile::Apfs(inode)) => {
                fs.read_file_slice(inode, offset, length)
            }
            (DetectedFs::Folder(fs), DetectedFile::Folder(file)) => {
                fs.read_file_slice(file, offset, length)
            }
            _ => Err("filesystem / record variant mismatch".into()),
        }
    }
    fn list_dir(
        &mut self,
        file: &Self::FileType,
    ) -> Result<Vec<Self::DirectoryType>, Box<dyn Error>> {
        match (self, file) {
            (DetectedFs::Ext(fs), DetectedFile::Ext(inode)) => fs
                .list_dir(inode)
                .map(|v| v.into_iter().map(DetectedDir::Ext).collect()),
            (DetectedFs::Ntfs(fs), DetectedFile::Ntfs(rec)) => fs
                .list_dir(rec.id())
                .map(|v| v.into_iter().map(DetectedDir::Ntfs).collect()),
            (DetectedFs::Exfat(fs), DetectedFile::Exfat(inode)) => Filesystem::list_dir(fs, inode)
                .map(|v| v.into_iter().map(DetectedDir::Exfat).collect()),
            (DetectedFs::Apfs(fs), DetectedFile::Apfs(inode)) => Filesystem::list_dir(fs, inode)
                .map(|v| v.into_iter().map(DetectedDir::Apfs).collect()),
            (DetectedFs::Folder(fs), DetectedFile::Folder(file)) => Filesystem::list_dir(fs, file)
                .map(|v| v.into_iter().map(DetectedDir::Folder).collect()),
            _ => Err("filesystem / record variant mismatch".into()),
        }
    }

    fn get_root_file_id(&self) -> u64 {
        match self {
            DetectedFs::Ext(fs) => fs.get_root_file_id(),
            DetectedFs::Ntfs(fs) => fs.get_root_file_id(),
            DetectedFs::Exfat(fs) => fs.get_root_file_id(),
            DetectedFs::Apfs(fs) => fs.get_root_file_id(),
            DetectedFs::Folder(fs) => fs.get_root_file_id(),
        }
    }
    fn walk_fs(
        &mut self,
        callback: &mut dyn FnMut(crate::filesystem::WalkEvent),
    ) -> Result<(), Box<dyn Error>> {
        match self {
            DetectedFs::Ext(fs) => fs.walk_fs(callback),
            DetectedFs::Ntfs(fs) => fs.walk_fs(callback),
            DetectedFs::Exfat(fs) => fs.walk_fs(callback),
            DetectedFs::Apfs(fs) => fs.walk_fs(callback),
            DetectedFs::Folder(fs) => fs.walk_fs(callback),
        }
    }
    fn record_to_file(&self, record: &Self::FileType, inode_num: u64, absolute_path: &str) -> File {
        match (self, record) {
            (DetectedFs::Ext(fs), DetectedFile::Ext(inode)) => {
                fs.record_to_file(inode, inode_num, absolute_path)
            }
            (DetectedFs::Ntfs(fs), DetectedFile::Ntfs(rec)) => {
                fs.record_to_file(rec, inode_num, absolute_path)
            }
            (DetectedFs::Exfat(fs), DetectedFile::Exfat(inode)) => {
                fs.record_to_file(inode, inode_num, absolute_path)
            }
            (DetectedFs::Apfs(fs), DetectedFile::Apfs(inode)) => {
                fs.record_to_file(inode, inode_num, absolute_path)
            }
            (DetectedFs::Folder(fs), DetectedFile::Folder(file)) => {
                fs.record_to_file(file, inode_num, absolute_path)
            }
            _ => unreachable!("filesystem / record variant mismatch"),
        }
    }
}

pub fn detect_filesystem(
    body: &Body,
    offset: u64,
    partition_size: u64,
    keys: Option<KeyMaterial>,
) -> Result<DetectedFs<ImageStream>, Box<dyn std::error::Error>> {
    let partition = BodySlice::new(body, offset, partition_size)
        .map_err(|e| format!("Could not create BodySlice: {e}"))?;
    if let Ok(ext_fs) = ExtFS::new(ImageStream::Raw(partition)) {
        info!("Detected an Extended filesystem.");
        return Ok(DetectedFs::Ext(ext_fs));
    }

    let partition = BodySlice::new(body, offset, partition_size)
        .map_err(|e| format!("Could not create BodySlice: {e}"))?;
    if let Ok(apfs) = APFS::new(ImageStream::Raw(partition))
        && let Ok(apfs_fs) = ApfsFs::new(apfs)
    {
        info!("Detected an APFS filesystem/container.");
        return Ok(DetectedFs::Apfs(apfs_fs));
    }

    let partition = BodySlice::new(body, offset, partition_size)
        .map_err(|e| format!("Could not create BodySlice: {e}"))?;
    if let Ok(exfat) = ExFatFS::new(ImageStream::Raw(partition)) {
        info!("Detected an exFAT filesystem.");
        return Ok(DetectedFs::Exfat(exfat));
    }

    let partition = BodySlice::new(body, offset, partition_size)
        .map_err(|e| format!("Could not create BodySlice: {e}"))?;
    match NTFS::new(ImageStream::Raw(partition)) {
        Ok(ntfs) => {
            info!("Detected an NT filesystem.");
            return Ok(DetectedFs::Ntfs(ntfs));
        }
        Err(e) if e.to_string().contains("-FVE-FS-") => {
            if let Some(mut km) = keys {
                if let Some(fvek) = km.bitlocker_fvek.take() {
                    info!("BitLocker detected. Attempting to decrypt with provided FVEK...");
                    let partition_for_bl = BodySlice::new(body, offset, partition_size)
                        .map_err(|e| format!("Could not create BodySlice for BL: {e}"))?;

                    match BitLockerStream::new(partition_for_bl, &fvek, 512) {
                        Ok(bl_stream) => match NTFS::new(ImageStream::BitLocker(bl_stream)) {
                            Ok(ntfs) => {
                                info!("Successfully detected BitLocker-decrypted NT filesystem.");
                                return Ok(DetectedFs::Ntfs(ntfs));
                            }
                            Err(err) => {
                                return Err(format!(
                                    "Failed to parse NTFS over BitLocker: {}",
                                    err
                                )
                                .into());
                            }
                        },
                        Err(err) => {
                            return Err(
                                format!("Failed to initialize BitLocker stream: {}", err).into()
                            );
                        }
                    }
                } else {
                    return Err(
                        "Partition is BitLocker-encrypted (-FVE-FS-) but no FVEK was provided."
                            .into(),
                    );
                }
            } else {
                return Err(
                    "Partition is BitLocker-encrypted (-FVE-FS-) but no keys were provided.".into(),
                );
            }
        }
        Err(_) => {}
    }

    Err(format!("No supported filesystem detected at offset {offset}").into())
}

pub fn detect_filesystem_from_path(
    path: &str,
) -> Result<DetectedFs<ImageStream>, Box<dyn std::error::Error>> {
    let folder_fs = FolderFS::new(std::path::PathBuf::from(path));
    Ok(DetectedFs::Folder(folder_fs))
}