Main file added

.gitignore

@@ -5,6 +5,7 @@
 
 # Data folder
 data/
+data
 
 # Byte-compiled / optimized / DLL files
 __pycache__/

README.md

@@ -4,6 +4,10 @@ Share files via a bridge server using TCP over SSL and end-to-end encryption.
 
 ## Requirements
 Python3.8+ is needed for this package.
+You may find it [here](https://www.python.org/downloads/).
+
+OpenSSL 1.1.1+ is required as well to handle SSL connection and end-to-end cryptography.
+On Windows, installing [git for Windows](https://gitforwindows.org/) will install OpenSSL as well.
 
 ## Usage
 If you need a virtual environment, create it.
@@ -29,6 +33,7 @@ python -m filebridging.client --help
     python -m filebridging.client r --host localhost --port 5000 --certificate ~/.ssh/server.crt --token 12345678 --password supersecretpasswordhere --path ~/Downloads 
     ```
 
+
 * Client-client example
     ```bash
     # 2 distinct tabs
@@ -37,6 +42,7 @@ python -m filebridging.client --help
     ```
     The receiver client may be standalone as well: just add the `--key` parameter (for SSL-secured sessions) and the `--standalone` flag. 
 
+
 * Configuration file example
     ```python
     #!/bin/python
@@ -51,3 +57,33 @@ python -m filebridging.client --help
     token = 'sessiontok'
     file_path = '.'
     ```
+
+## Generating SSL certificates
+
+You may use `filebridging.create_certificate.py` script or use openssl from the command line.
+
+### Via script
+```bash
+python -m filebridging.create_certificate --name example --domain example.com --force
+```
+
+### Via command line
+Store configuration in file `mycert.csr.cnf` and run the following command to generate a self-signed SSL certificate.
+```bash
+openssl req -newkey rsa:4096 -nodes -keyout ./mycert.key \
+ -x509 -days 365 -out ./mycert.crt \
+ -config mycert.csr.cnf
+```
+
+
+**mycert.csr.cnf**
+```text
+[ req ]
+default_bits = 4096
+prompt = no
+default_md = sha256
+distinguished_name = dn
+
+[ dn ]
+CN = yourdomain.com
+```

filebridging/__init__.py

@@ -13,6 +13,6 @@ __author__ = "Davide Testa"
 __email__ = "davide@davte.it"
 __credits__ = []
 __license__ = "GNU General Public License v3.0"
-__version__ = "0.0.1"
+__version__ = "0.0.10"
 __maintainer__ = "Davide Testa"
 __contact__ = "t.me/davte"

filebridging/__main__.py

@@ -0,0 +1,6 @@
+mode = input("Do you want to run a filebridging (S)erver or (C)lient?\t\t")
+if mode.lower().startswith('s'):
+    from .server import main
+else:
+    from .client import main
+main()

filebridging/client.py

@@ -40,26 +40,27 @@ class Client:
                  buffer_length_limit=10 ** 4,
                  file_path=None,
                  password=None,
-                 token=None):
+                 token=None,
+                 ssl_handshake_timeout=None):
         self._host = host
         self._port = port
         self._ssl_context = ssl_context
         self._action = action
         self._standalone = standalone
-        self._stopping = False
+        self._file_path = file_path
-        self._reader = None
+        self._password = password
-        self._writer = None
+        self._token = token
-        # Shared queue of bytes
+        self._ssl_handshake_timeout = ssl_handshake_timeout
-        self.buffer = collections.deque()
         # How many bytes per chunk
         self._buffer_chunk_size = buffer_chunk_size
         # How many chunks in buffer
         self._buffer_length_limit = buffer_length_limit
-        self._file_path = file_path
+        # Shared queue of bytes
+        self.buffer = collections.deque()
         self._working = False
-        self._token = token
+        self._stopping = False
-        self._password = password
+        self._reader = None
-        self._ssl_context = None
+        self._writer = None
         self._encryption_complete = False
         self._file_name = None
         self._file_size = None
@@ -139,6 +140,16 @@ class Client:
     def set_ssl_context(self, ssl_context: ssl.SSLContext):
         self._ssl_context = ssl_context
 
+    @property
+    def ssl_handshake_timeout(self) -> Union[int, None]:
+        """Return SSL handshake timeout.
+
+        If SSL context is not set, return None.
+        Otherwise, return seconds to wait before considering handshake failed.
+        """
+        if self.ssl_context:
+            return self._ssl_handshake_timeout
+
     @property
     def token(self):
         """Session token.
@@ -199,11 +210,16 @@ class Client:
                 reader, writer = await asyncio.open_connection(
                     host=self.host,
                     port=self.port,
-                    ssl=self.ssl_context
+                    ssl=self.ssl_context,
+                    ssl_handshake_timeout=self.ssl_handshake_timeout
                 )
-            except (ConnectionRefusedError, ConnectionResetError) as exception:
+            except (ConnectionRefusedError, ConnectionResetError,
+                    ConnectionAbortedError) as exception:
                 logging.error(f"Connection error: {exception}")
                 return
+            except ssl.SSLError as exception:
+                logging.error(f"SSL error: {exception}")
+                return
             await self.connect(reader=reader, writer=writer)
 
     async def _connect(self, reader: asyncio.StreamReader,
@@ -272,7 +288,7 @@ class Client:
         while 1:
             server_hello = await self.reader.readline()
             if not server_hello:
-                logging.error("Server disconnected.")
+                logging.error("Server refused connection.")
                 return
             server_hello = server_hello.decode('utf-8').strip('\n').split('|')
             if self.action == 'receive' and server_hello[0] == 's':
@@ -383,6 +399,7 @@ class Client:
                 self.print_progress_bar(
                     progress=new_progress,
                     bytes_=bytes_sent,
+                    force=(new_progress == 100)
                 )
         print()  # New line after progress_bar
         writer.close()
@@ -415,7 +432,8 @@ class Client:
                 )
                 self.print_progress_bar(
                     progress=new_progress,
-                    bytes_=bytes_received
+                    bytes_=bytes_received,
+                    force=(new_progress == 100)
                 )
                 if not input_data:
                     break

filebridging/create_certificate.py

@@ -0,0 +1,126 @@
+"""Create a SSL certificate.
+
+Requirements: OpenSSL.
+"""
+
+import argparse
+import logging
+import os
+import subprocess
+
+
+def get_paths(path):
+    """"""
+    return [
+        os.path.abspath(path) + string
+        for string in (".crt", ".key", "csr.cnf")
+    ]
+
+
+def main():
+    # noinspection SpellCheckingInspection
+    log_formatter = logging.Formatter(
+        "%(asctime)s [%(module)-15s %(levelname)-8s]     %(message)s",
+        style='%'
+    )
+    root_logger = logging.getLogger()
+    root_logger.setLevel(logging.DEBUG)
+
+    console_handler = logging.StreamHandler()
+    console_handler.setFormatter(log_formatter)
+    console_handler.setLevel(logging.DEBUG)
+    root_logger.addHandler(console_handler)
+
+    cli_parser = argparse.ArgumentParser(description='Create SSL certificate',
+                                         allow_abbrev=False)
+    cli_parser.add_argument('-n', '--name',
+                            type=str,
+                            default=None,
+                            required=False,
+                            help='Certificate, key and configuration file name')
+    cli_parser.add_argument('-d', '--domain',
+                            type=str,
+                            default=None,
+                            required=False,
+                            help='Server domain (e.g. example.com)')
+    cli_parser.add_argument('-f', '--force', '--overwrite',
+                            action='store_true',
+                            help='Overwrite certificate and key if they exist')
+    arguments = vars(cli_parser.parse_args())
+    name = arguments['name']
+    if name is None:
+        try:
+            from config import name
+        except ImportError:
+            name = None
+    while not name or not os.access(os.path.dirname(os.path.abspath(name)),
+                                    os.W_OK):
+        try:
+            name = input(
+                "Enter a valid file name for certificate, key and "
+                "configuration file. Directory must be writeable.\n"
+                "\t\t"
+            )
+        except KeyboardInterrupt:
+            print()
+            logging.error("Aborting...")
+            return
+    certificate_path, key_path, configuration_path = get_paths(
+        name
+    )
+    if not os.access(os.path.dirname(certificate_path), os.W_OK):
+        logging.error(f"Invalid path `{certificate_path}`!")
+        return
+    if any(
+            os.path.isfile(path)
+            for path in (certificate_path, key_path, configuration_path)
+    ) and not arguments['force'] and not input(
+        "Do you want to overwrite existing certificate, key and "
+        "configuration file?"
+        "\n[Y]es or [N]o\t\t\t\t"
+    ).lower().startswith('y'):
+        logging.error("Interrupted. Provide a different --name.")
+        return
+    domain = arguments['domain']
+    if domain is None:
+        try:
+            from config import domain
+        except ImportError:
+            domain = None
+    while not domain:
+        domain = input("Enter server domain (e.g. example.com)\n\t\t")
+    with open(configuration_path, 'w') as configuration_file:
+        logging.info("Writing configuration file...")
+        configuration_file.write(
+            "[req]\n"
+            "default_bits = 4096\n"
+            "prompt = no\n"
+            "default_md = sha256\n"
+            "distinguished_name = dn\n"
+            "\n"
+            "[dn]\n"
+            f"CN = {domain}\n"
+        )
+    logging.info("Generating certificate and key...")
+    subprocess.run(
+        [
+            f"openssl req -newkey rsa:4096 -nodes "
+            f"-keyout \"{key_path}\" -x509 -days 365 "
+            f"-out \"{certificate_path}\" "
+            f"-config \"{configuration_path}\""
+        ],
+        capture_output=True,
+        text=True,
+        shell=True
+    )
+    with open(certificate_path, 'r') as certificate_file:
+        logging.info(
+            "Certificate:\n\n{certificate}".format(
+                certificate=''.join(certificate_file.readlines())
+            ),
+        )
+    logging.info("Done!")
+
+
+if __name__ == '__main__':
+    main()

filebridging/server.py

@@ -33,7 +33,6 @@ class Server:
         self._buffer_length_limit = buffer_length_limit
         self._working = False
         self._server = None
-        self._ssl_context = None
 
     @property
     def host(self) -> str:
@@ -74,7 +73,7 @@ class Server:
     def set_ssl_context(self, ssl_context: ssl.SSLContext):
         self._ssl_context = ssl_context
 
-    async def run_reader(self, reader, connection_token):
+    async def run_reader(self, reader: asyncio.StreamReader, connection_token):
         while 1:
             try:
                 # Wait one second if buffer is full
@@ -91,7 +90,7 @@ class Server:
             except Exception as e:
                 logging.error(f"Unexpected exception:\n{e}", exc_info=True)
 
-    async def run_writer(self, writer, connection_token):
+    async def run_writer(self, writer: asyncio.StreamWriter, connection_token):
         consecutive_interruptions = 0
         errors = 0
         while connection_token in self.buffers:
@@ -101,6 +100,7 @@ class Server:
                 # Slow down if buffer is empty; after 1.5 s of silence, break
                 consecutive_interruptions += 1
                 if consecutive_interruptions > 3:
+                    logging.error("Too many interruptions...")
                     break
                 await asyncio.sleep(.5)
                 continue
@@ -130,7 +130,11 @@ class Server:
         Decide whether client is sender or receiver and start transmission.
         """
         client_hello = await reader.readline()
+        try:
             client_hello = client_hello.decode('utf-8').strip('\n').split('|')
+        except UnicodeDecodeError:
+            logging.error("Invalid client hello.")
+            return
         if len(client_hello) != 4:
             await self.refuse_connection(writer=writer,
                                          message="Invalid client_hello!")
@@ -163,6 +167,7 @@ class Server:
             else:
                 return 0  # On success, return 0
             # On exception, disconnect and return 1
+            logging.error("Disconnecting...")
             self.disconnect(connection_token=connection_token)
             return 1
 
@@ -234,7 +239,9 @@ class Server:
             return
 
     def disconnect(self, connection_token: str) -> None:
+        if connection_token in self.buffers:
             del self.buffers[connection_token]
+        if connection_token in self.connections:
             del self.connections[connection_token]
 
     def run(self):

filebridging/utilities.py

@@ -4,6 +4,8 @@ import logging
 import shutil
 import signal
 import sys
+import time
+
 from typing import Union
 
 units_of_measurements = {
@@ -75,9 +77,9 @@ def timed_action(interval: Union[int, float, datetime.timedelta] = None):
         timedelta = interval
 
     def timer(function_to_time):
-        def timed_function(*args, **kwargs):
+        def timed_function(*args, force: bool = False, **kwargs):
             nonlocal last_call
-            if now() > last_call + timedelta:
+            if force or now() > last_call + timedelta:
                 last_call = now()
                 return function_to_time(*args, **kwargs)
             return
@@ -86,11 +88,17 @@ def timed_action(interval: Union[int, float, datetime.timedelta] = None):
     return timer
 
 
-def timed_input(message: str = None,
+def unix_timed_input(message: str = None,
                      timeout: int = 5):
+    """Print `message` and return input within `timeout` seconds.
+
+    If nothing was entered in time, return None.
+    This works only on unix systems, since `signal.alarm` is needed.
+    """
     class TimeoutExpired(Exception):
         pass
 
+    # noinspection PyUnusedLocal
     def interrupted(signal_number, stack_frame):
         """Called when read times out."""
         raise TimeoutExpired
@@ -108,3 +116,27 @@ def timed_input(message: str = None,
         logging.info("Timeout!")
     signal.alarm(0)
     return given_input
+
+
+def non_unix_timed_input(message: str = None,
+                         timeout: int = 5):
+    """Print message and wait `timeout` seconds before reading standard input.
+
+    This works on all systems, but cannot last less then `timeout` even if
+    user presses enter.
+    """
+    print(message, end='')
+    time.sleep(timeout)
+    input_ = sys.stdin.readline()
+    if not input_.endswith("\n"):
+        print()  # Print end of line
+    if input_:
+        return input_
+    return
+
+
+timed_input = (
+    unix_timed_input
+    if sys.platform.startswith('linux')
+    else non_unix_timed_input()
+)