Make encryption work with zip files (#196)

- Fix encryption in combination with zip files.
- Fix bug in decrypter where an error was thrown on success.

acquire/crypt.py

@@ -113,7 +113,7 @@ def tell(self):
         return self.fh.tell()
 
     def seek(self, pos, whence=io.SEEK_CUR):
-        raise TypeError("seeking is not allowed")
+        raise io.UnsupportedOperation("seeking is not allowed")
 
     def close(self):
         self.finalize()

acquire/outputs/zip.py

@@ -48,7 +48,7 @@ def __init__(
 
         if encrypt:
             self._fh = EncryptedStream(self.path.open("wb"), public_key)
-            self.archive = zipfile.ZipFile(fileobj=self._fh, mode="w", compression=self.compression, allowZip64=True)
+            self.archive = zipfile.ZipFile(self._fh, mode="w", compression=self.compression, allowZip64=True)
         else:
             self.archive = zipfile.ZipFile(self.path, mode="w", compression=self.compression, allowZip64=True)
 

acquire/tools/decrypter.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import argparse
 import base64
 import contextlib
@@ -14,6 +16,9 @@
 from datetime import datetime, timezone
 from pathlib import Path
 from queue import Empty as QueueEmptyError
+from queue import Queue
+from threading import Event
+from typing import BinaryIO, Iterator
 from urllib import request
 from urllib.error import HTTPError
 from urllib.parse import urljoin
@@ -73,7 +78,7 @@ class VerifyError(Exception):
 
 
 class EncryptedFile(AlignedStream):
-    def __init__(self, fh, key_file=None, key_server=None):
+    def __init__(self, fh: BinaryIO, key_file: Path | None = None, key_server: str | None = None) -> None:
         self.fh = fh
         self.key_file = key_file
         self.key_server = key_server
@@ -116,10 +121,10 @@ def __init__(self, fh, key_file=None, key_server=None):
     def seekable(self):
         return False
 
-    def seek(self, pos, whence=io.SEEK_CUR):
+    def seek(self, pos: int, whence: int = io.SEEK_CUR) -> int:
         raise io.UnsupportedOperation("seeking is not allowed")
 
-    def _read(self, offset, length):
+    def _read(self, offset: int, length: int) -> bytes:
         if not self.size:
             result = []
 
@@ -162,25 +167,25 @@ def _read(self, offset, length):
             read_size = max(0, min(length, self.size - offset))
             return self.cipher.decrypt(self.fh.read(read_size))
 
-    def chunks(self, chunk_size=CHUNK_SIZE):
+    def chunks(self, chunk_size: int = CHUNK_SIZE) -> Iterator[bytes]:
         while True:
             chunk = self.read(chunk_size)
             if not chunk:
                 break
             yield chunk
 
-    def verify(self):
+    def verify(self) -> None:
         try:
             self.cipher.verify(self.digest)
         except ValueError:
             raise VerifyError("Digest check failed")
 
     @property
-    def file_header(self):
+    def file_header(self) -> c_acquire.file:
         return self._file_header
 
     @file_header.setter
-    def file_header(self, file_header):
+    def file_header(self, file_header: c_acquire.file) -> None:
         if file_header.magic != FILE_MAGIC:
             raise ValueError(f"Invalid file magic: {file_header.magic}")
 
@@ -193,31 +198,31 @@ def file_header(self, file_header):
         self._file_header = file_header
 
     @property
-    def header(self):
+    def header(self) -> c_acquire.header:
         return self._header
 
     @header.setter
-    def header(self, header):
+    def header(self, header: c_acquire.header) -> None:
         if header.magic != HEADER_MAGIC:
             raise ValueError(f"Invalid header magic: {header.magic}")
         self._header = header
 
     @property
-    def footer(self):
+    def footer(self) -> c_acquire.footer:
         return self._footer
 
     @footer.setter
-    def footer(self, footer):
+    def footer(self, footer: c_acquire.footer) -> None:
         if footer.magic != FOOTER_MAGIC:
             raise ValueError(f"Invalid footer magic: {footer}")
         self._footer = footer
 
     @property
-    def timestamp(self):
+    def timestamp(self) -> datetime:
         return datetime.fromtimestamp(self.file_header.timestamp, timezone.utc)
 
 
-def decrypt_header(header, fingerprint, key_file=None, key_server=None):
+def decrypt_header(header, fingerprint: bytes, key_file: Path | None = None, key_server: str | None = None) -> bytes:
     if not key_file and not key_server:
         raise ValueError("Need either key file or key server")
 
@@ -264,7 +269,16 @@ def check_existing(in_path: Path, out_path: Path, status_queue: multiprocessing.
     return False
 
 
-def worker(task_id, stop_event, status_queue, in_path, out_path, key_file=None, key_server=None, clobber=False):
+def worker(
+    task_id: int,
+    stop_event: Event,
+    status_queue: Queue,
+    in_path: Path,
+    out_path: Path,
+    key_file: Path | None = None,
+    key_server: str | None = None,
+    clobber: bool = False,
+) -> None:
     success = False
     message = "An unknown error occurred"
 
@@ -325,23 +339,23 @@ def worker(task_id, stop_event, status_queue, in_path, out_path, key_file=None,
         _exit(status_queue, task_id, str(in_path), message, success)
 
 
-def _start(queue, task_id):
+def _start(queue: Queue, task_id: int) -> None:
     queue.put_nowait((STATUS_START, task_id))
 
 
-def _update(queue, task_id, *args, **kwargs):
+def _update(queue: Queue, task_id: int, *args, **kwargs) -> None:
     queue.put_nowait((STATUS_UPDATE, (task_id, args, kwargs)))
 
 
-def _info(queue, msg):
+def _info(queue: Queue, msg: str) -> None:
     queue.put_nowait((STATUS_INFO, msg))
 
 
-def _exit(queue: multiprocessing.Queue, task_id: int, in_path: str, message: str, success: bool):
+def _exit(queue: multiprocessing.Queue, task_id: int, in_path: str, message: str, success: bool) -> None:
     queue.put_nowait((STATUS_EXIT, (task_id, in_path, message, success)))
 
 
-def setup_logging(logger, verbosity):
+def setup_logging(logger: logging.Logger, verbosity: int) -> None:
     if verbosity == 1:
         level = logging.ERROR
     elif verbosity == 2:
@@ -360,7 +374,7 @@ def setup_logging(logger, verbosity):
     logger.setLevel(level)
 
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser()
     parser.add_argument("files", nargs="+", type=Path, help="paths to encrypted files")
     parser.add_argument("-o", "--output", type=Path, help="optional path to output file")
@@ -476,12 +490,12 @@ def main():
             # If no successful results, return 1
             if not any(successes):
                 exit_code = 1
-            # Else, if some results were successful return 2
+            # Else, if some results but not all were successful return 2
             elif not all(successes):
                 exit_code = 2
-            # Else, if all were successful but there were still tasks to handle, return 2
-            elif all(success) and tasks:
-                exit_code = 2
+            # Else, if all were successful but there were still tasks to handle, return 3
+            elif tasks:
+                exit_code = 3
     exit(exit_code)
 
 

tests/conftest.py

@@ -33,3 +33,9 @@ def mock_target(mock_fs: VirtualFilesystem) -> Target:
     target.filesystems.add(mock_fs)
     target.os = "mock"
     return target
+
+
+@pytest.fixture
+def public_key() -> bytes:
+    with open("tests/data/public_key.pem", "r") as f:
+        return f.read()

tests/data/private_key.pem

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----

tests/data/public_key.pem

@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAw3e6lxHu3EeG9AxZrM0J
+uTDRT5H/7iXeYumOMmtKa7bPbOJg3UvdKA1Le27y5eNov3gfktX8PVKZiq/DgVed
+VaBT7MC1UsB4aOy42xrwUoCglt9bJGpYDpggIgpegaqoyO3iKsScd1dvhrVtfb9B
+L2zyTbOIFpSyM59FmSeuR1jWcU6A/TXDNrmXiBcc4lBb0GL9Tc5Iofx1gPBcPEna
+6tyTd0RvY4pCUh/zIrFNuSD+XoT+YOumpDwrnwQhHOmNjhOMAEO7GwTKX/+jy2Rx
+glTJxPE1xgVJe5vVFcHcob3yBQTYRopaarUkIZaspq5KO0e7meseYECM/2M1Fvx6
+PQIDAQAB
+-----END PUBLIC KEY-----

tests/test_outputs_tar.py

@@ -5,6 +5,7 @@
 from dissect.target.filesystem import VirtualFilesystem
 
 from acquire.outputs import TarOutput
+from acquire.tools.decrypter import EncryptedFile
 
 
 @pytest.fixture(params=[(True, "gzip"), (True, "bzip2"), (True, "xz"), (False, None)])
@@ -41,3 +42,20 @@ def test_tar_output_write_entry(mock_fs: VirtualFilesystem, tar_output: TarOutpu
         assert file.issym()
     elif entry.is_file():
         assert file.isfile()
+
+
+def test_tar_output_encrypt(mock_fs: VirtualFilesystem, public_key: bytes, tmp_path: Path) -> None:
+    entry_name = "/foo/bar/some-file"
+    entry = mock_fs.get(entry_name)
+    tar_output = TarOutput(tmp_path, compress=True, compression_method="gzip", encrypt=True, public_key=public_key)
+    tar_output.write_entry(entry_name, entry)
+    tar_output.close()
+
+    encrypted_stream = EncryptedFile(tar_output.path.open("rb"), Path("tests/data/private_key.pem"))
+    decrypted_path = tmp_path / "decrypted.tar"
+    # Direct streaming is not an option because tarfile needs seek when reading from encrypted files directly
+    with open(decrypted_path, "wb") as f:
+        f.write(encrypted_stream.read())
+
+    tar_file = tarfile.open(name=decrypted_path, mode="r")
+    assert entry.open().read() == tar_file.extractfile(entry_name).read()

tests/test_outputs_zip.py

@@ -6,6 +6,7 @@
 from dissect.target.filesystem import VirtualFilesystem
 
 from acquire.outputs import ZipOutput
+from acquire.tools.decrypter import EncryptedFile
 
 
 @pytest.fixture(params=[(True, "deflate"), (True, "bzip2"), (True, "lzma"), (False, None)])
@@ -45,3 +46,20 @@ def test_zip_output_write_entry(mock_fs: VirtualFilesystem, zip_output: ZipOutpu
         assert stat.S_ISLNK(file_type)
     elif entry.is_file():
         assert stat.S_ISREG(file_type)
+
+
+def test_zip_output_encrypt(mock_fs: VirtualFilesystem, public_key: bytes, tmp_path: Path) -> None:
+    entry_name = "/foo/bar/some-file"
+    entry = mock_fs.get(entry_name)
+    zip_output = ZipOutput(tmp_path, compress=True, compression_method="bzip2", encrypt=True, public_key=public_key)
+    zip_output.write_entry(entry_name, entry)
+    zip_output.close()
+
+    encrypted_stream = EncryptedFile(zip_output.path.open("rb"), Path("tests/data/private_key.pem"))
+    decrypted_path = tmp_path / "decrypted.zip"
+    # Direct streaming is not an option because zipfile needs seek when reading from encrypted files directly
+    with open(decrypted_path, "wb") as f:
+        f.write(encrypted_stream.read())
+
+    zip_file = zipfile.ZipFile(decrypted_path, mode="r")
+    assert entry.open().read() == zip_file.open(entry_name).read()