1 files changed, 114 insertions, 0 deletions
diff --git a/foreign/client_handling/lazagne/softwares/memory/libkeepass/hbio.py b/foreign/client_handling/lazagne/softwares/memory/libkeepass/hbio.py
new file mode 100644
index 0000000..ade6e96
--- /dev/null
+++ b/foreign/client_handling/lazagne/softwares/memory/libkeepass/hbio.py
@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+import hashlib
+import io
+import struct
+
+# default from KeePass2 source
+BLOCK_LENGTH = 1024 * 1024
+
+try:
+    file_types = (file, io.IOBase)
+except NameError:
+    file_types = (io.IOBase,)
+
+# HEADER_LENGTH = 4+32+4
+
+def read_int(stream, length):
+    try:
+        return struct.unpack('<I', stream.read(length))[0]
+    except Exception:
+        return None
+
+
+class HashedBlockIO(io.BytesIO):
+    """
+    The data is stored in hashed blocks. Each block consists of a block index (4
+    bytes), the hash (32 bytes) and the block length (4 bytes), followed by the
+    block data. The block index starts counting at 0. The block hash is a
+    SHA-256 hash of the block data. A block has a maximum length of
+    BLOCK_LENGTH, but can be shorter.
+    
+    Provide a I/O stream containing the hashed block data as the `block_stream`
+    argument when creating a HashedBlockReader. Alternatively the `bytes`
+    argument can be used to hand over data as a string/bytearray/etc. The data
+    is verified upon initialization and an IOError is raised when a hash does
+    not match.
+    
+    HashedBlockReader is a subclass of io.BytesIO. The inherited read, seek, ...
+    functions shall be used to access the verified data.
+    """
+
+    def __init__(self, block_stream=None, bytes=None):
+        io.BytesIO.__init__(self)
+        input_stream = None
+        if block_stream is not None:
+            if not (isinstance(block_stream, io.IOBase) or isinstance(block_stream, file_types)):
+                raise TypeError('Stream does not have the buffer interface.')
+            input_stream = block_stream
+        elif bytes is not None:
+            input_stream = io.BytesIO(bytes)
+        if input_stream is not None:
+            self.read_block_stream(input_stream)
+
+    def read_block_stream(self, block_stream):
+        """
+        Read the whole block stream into the self-BytesIO.
+        """
+        if not (isinstance(block_stream, io.IOBase) or isinstance(block_stream, file_types)):
+            raise TypeError('Stream does not have the buffer interface.')
+        while True:
+            data = self._next_block(block_stream)
+            if not self.write(data):
+                break
+        self.seek(0)
+
+    def _next_block(self, block_stream):
+        """
+        Read the next block and verify the data.
+        Raises an IOError if the hash does not match.
+        """
+        index = read_int(block_stream, 4)
+        bhash = block_stream.read(32)
+        length = read_int(block_stream, 4)
+
+        if length > 0:
+            data = block_stream.read(length)
+            if hashlib.sha256(data).digest() == bhash:
+                return data
+            else:
+                raise IOError('Block hash mismatch error.')
+        return bytes()
+
+    def write_block_stream(self, stream, block_length=BLOCK_LENGTH):
+        """
+        Write all data in this buffer, starting at stream position 0, formatted
+        in hashed blocks to the given `stream`.
+        
+        For example, writing data from one file into another as hashed blocks::
+            
+            # create new hashed block io without input stream or data
+            hb = HashedBlockIO()
+            # read from a file, write into the empty hb
+            with open('sample.dat', 'rb') as infile:
+                hb.write(infile.read())
+                # write from the hb into a new file
+                with open('hb_sample.dat', 'w') as outfile:
+                    hb.write_block_stream(outfile)
+        """
+        if not (isinstance(stream, io.IOBase) or isinstance(stream, file_types)):
+            raise TypeError('Stream does not have the buffer interface.')
+        index = 0
+        self.seek(0)
+        while True:
+            data = self.read(block_length)
+            if data:
+                stream.write(struct.pack('<I', index))
+                stream.write(hashlib.sha256(data).digest())
+                stream.write(struct.pack('<I', len(data)))
+                stream.write(data)
+                index += 1
+            else:
+                stream.write(struct.pack('<I', index))
+                stream.write('\x00' * 32)
+                stream.write(struct.pack('<I', 0))
+                break