SSH HTTPS Port forwarding python3 asyncio selectors security

gistfile1.txt

# 2024-03-24 Gerben Aaltink
# Application for hosting both HTTPS and SSH on port 443
# Benefits:
#  - port 443 is allowed in any network 
#  - port hiding for hackers  
import asyncio


LISTEN_PORT = 443
LISTEN_HOST = '0.0.0.0'
SSH_FORWARD_TO_HOST = '127.0.0.1'
SSH_FORWARD_TO_PORT = 22 
HTTPS_FORWARD_TO_HOST = '127.0.0.1'
HTTPS_FORWARD_TO_PORT = 4430


async def forward(reader, writer, direction):
    while True:
        data = await reader.read(4096)
        if not data:
            writer.transport.close()
            break 
        writer.write(data)


async def handle_client(reader, writer):
    addr = writer.get_extra_info('peername')
    data = await reader.read(3)
    if data[0:3] == b'SSH':
        reader_up, writer_up = await asyncio.open_connection(
            SSH_FORWARD_TO_HOST, SSH_FORWARD_TO_PORT
        )
    else:
        reader_up, writer_up = await asyncio.open_connection(
            HTTPS_FORWARD_TO_HOST, HTTPS_FORWARD_TO_PORT
        )

    writer_up.write(data)
    await writer_up.drain()

    await asyncio.gather(
        forward(reader_up, writer),
        forward(reader, writer_up)
    )

    print(addr, "closed")
    

async def main():
    server = await asyncio.start_server(
        handle_client, LISTEN_HOST, LISTEN_PORT
    )

    addrs = ', '.join(str(sock.getsockname()) for sock in server.sockets)
    print(f'Serving on {addrs}')

    async with server:
        await server.serve_forever()

asyncio.run(main())