Code review: 323820043: Fixed negative seeks in encrypted, encoded, a…

…nd compressed streams log2timeline#183
joachimmetz · Jun 25, 2017 · a889480 · a889480
1 parent 25ccf9c
commit a889480
Show file tree

Hide file tree

Showing 6 changed files with 159 additions and 0 deletions.
diff --git a/dfvfs/file_io/compressed_stream_io.py b/dfvfs/file_io/compressed_stream_io.py
@@ -283,10 +283,18 @@ def seek(self, offset, whence=os.SEEK_SET):
 
     if whence == os.SEEK_CUR:
       offset += self._current_offset
+
     elif whence == os.SEEK_END:
+      if self._uncompressed_stream_size is None:
+        self._uncompressed_stream_size = self._GetUncompressedStreamSize()
+        if self._uncompressed_stream_size is None:
+          raise IOError(u'Invalid uncompressed stream size.')
+
       offset += self._uncompressed_stream_size
+
     elif whence != os.SEEK_SET:
       raise IOError(u'Unsupported whence.')
+
     if offset < 0:
       raise IOError(u'Invalid offset value less than zero.')
 

diff --git a/dfvfs/file_io/encoded_stream_io.py b/dfvfs/file_io/encoded_stream_io.py
@@ -304,10 +304,18 @@ def seek(self, offset, whence=os.SEEK_SET):
 
     if whence == os.SEEK_CUR:
       offset += self._current_offset
+
     elif whence == os.SEEK_END:
+      if self._decoded_stream_size is None:
+        self._decoded_stream_size = self._GetDecodedStreamSize()
+        if self._decoded_stream_size is None:
+          raise IOError(u'Invalid decoded stream size.')
+
       offset += self._decoded_stream_size
+
     elif whence != os.SEEK_SET:
       raise IOError(u'Unsupported whence.')
+
     if offset < 0:
       raise IOError(u'Invalid offset value less than zero.')
 

diff --git a/dfvfs/file_io/encrypted_stream_io.py b/dfvfs/file_io/encrypted_stream_io.py
@@ -317,10 +317,18 @@ def seek(self, offset, whence=os.SEEK_SET):
 
     if whence == os.SEEK_CUR:
       offset += self._current_offset
+
     elif whence == os.SEEK_END:
+      if self._decrypted_stream_size is None:
+        self._decrypted_stream_size = self._GetDecryptedStreamSize()
+        if self._decrypted_stream_size is None:
+          raise IOError(u'Invalid decrypted stream size.')
+
       offset += self._decrypted_stream_size
+
     elif whence != os.SEEK_SET:
       raise IOError(u'Unsupported whence.')
+
     if offset < 0:
       raise IOError(u'Invalid offset value less than zero.')
 

diff --git a/tests/file_io/compressed_stream_io.py b/tests/file_io/compressed_stream_io.py
@@ -7,6 +7,7 @@
 except ImportError:
   lzma = None
 
+import os
 import unittest
 
 from dfvfs.file_io import compressed_stream_io
@@ -67,6 +68,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = compressed_stream_io.CompressedStream(self._resolver_context)
+    file_object.open(path_spec=self._compressed_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = compressed_stream_io.CompressedStream(self._resolver_context)
@@ -125,6 +137,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = compressed_stream_io.CompressedStream(self._resolver_context)
+    file_object.open(path_spec=self._compressed_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = compressed_stream_io.CompressedStream(self._resolver_context)
@@ -183,6 +206,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = compressed_stream_io.CompressedStream(self._resolver_context)
+    file_object.open(path_spec=self._compressed_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = compressed_stream_io.CompressedStream(self._resolver_context)
@@ -240,6 +274,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = compressed_stream_io.CompressedStream(self._resolver_context)
+    file_object.open(path_spec=self._compressed_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = compressed_stream_io.CompressedStream(self._resolver_context)

diff --git a/tests/file_io/encoded_stream_io.py b/tests/file_io/encoded_stream_io.py
@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 """Tests for the encoded stream file-like object."""
 
+import os
 import unittest
 
 from dfvfs.file_io import encoded_stream_io
@@ -62,6 +63,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encoded_stream_io.EncodedStream(self._resolver_context)
+    file_object.open(path_spec=self._encoded_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encoded_stream_io.EncodedStream(self._resolver_context)
@@ -119,6 +131,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encoded_stream_io.EncodedStream(self._resolver_context)
+    file_object.open(path_spec=self._encoded_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encoded_stream_io.EncodedStream(self._resolver_context)
@@ -176,6 +199,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encoded_stream_io.EncodedStream(self._resolver_context)
+    file_object.open(path_spec=self._encoded_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encoded_stream_io.EncodedStream(self._resolver_context)

diff --git a/tests/file_io/encrypted_stream_io.py b/tests/file_io/encrypted_stream_io.py
@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 """Tests for the encrypted stream file-like object."""
 
+import os
 import unittest
 
 from dfvfs.file_io import encrypted_stream_io
@@ -77,6 +78,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
+    file_object.open(path_spec=self._encrypted_stream_path_spec)
+
+    file_object.seek(-10 - self.padding_size, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
@@ -144,6 +156,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
+    file_object.open(path_spec=self._encrypted_stream_path_spec)
+
+    file_object.seek(-10 - self.padding_size, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
@@ -215,6 +238,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
+    file_object.open(path_spec=self._encrypted_stream_path_spec)
+
+    file_object.seek(-10 - self.padding_size, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
@@ -286,6 +320,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
+    file_object.open(path_spec=self._encrypted_stream_path_spec)
+
+    file_object.seek(-10 - self.padding_size, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
@@ -349,6 +394,17 @@ def testSeek(self):
 
     file_object.close()
 
+    # TODO: Test SEEK_CUR after open.
+
+    # Test SEEK_END after open.
+    file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)
+    file_object.open(path_spec=self._encrypted_stream_path_spec)
+
+    file_object.seek(-10, os.SEEK_END)
+    self.assertEqual(file_object.read(5), b'times')
+
+    file_object.close()
+
   def testRead(self):
     """Test the read functionality."""
     file_object = encrypted_stream_io.EncryptedStream(self._resolver_context)