TLS Handshake times out ssl python

Question

So I am trying to connect to different sites on the Internet through the proxy that I am currently trying to build.

If I try to connect to a website on port 80 EVERYTHING works perfectly. But when I try to connect to any https link it does not work.

I tried using a self signed certificate but that did not work.

I am now using the certifi lib and it looks like I made so progress.

The function I use for TLS handshake:

def do_handshake():
    ca_certificates = certifi.where()
    print("ca-certificate mozilla", ca_certificates)
    
    CIPHERS = 'ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:AES256-SHA'

    conn_s = ssl.wrap_socket(conn, ssl_version=ssl.PROTOCOL_TLSv1_2, cert_reqs=ssl.CERT_OPTIONAL, ca_certs=ca_certificates, do_handshake_on_connect=False)
    
    print("Initiating Handshake!")
    conn_s.do_handshake()
    print("Handshake Completed!")

I accept connection and start a new thread to process the request.

while True:

    conn, addr = s.accept()
    request = conn.recv(4704)
    print(request)

    thread = threading.Thread(target=url_string, args=(conn, addr))
    thread.setDaemon(True)
    thread.start()

The socket server runs on port 9000.

Now If I send a curl request I get some weird text showing in the terminal and it gets stuck on conn_s.do_handshake() forever and eventually gets timed out.

The headers I send through my socket server back to client:

HTTP/1.1 200 Connection established
< Content-Type: text/plain
< Connection: close
< Set-Cookie: cookie=verified, Expires=Saturday, 8 May 2021 03:10:29

The curl request: curl https://google.com --proxy 127.0.0.1:9000 -v

If I don't to the TLS handshake I get this error (and many more AAA):

curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number

I use the requests library to first send the get or post request to the url and then return it to conn.

How do I do the handshake successfully and send the request back to conn?

UPDATE:

So the handshake problem was fixed by sending the HTTP/1.1 200 Connection Established header. I checked and the headers were not being sent before the TLS handshake was done.

But still I get the same error:

curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number

the code:

import socket, ssl
import os, sys, threading
import requests
import datetime
import calendar


HOST = "0.0.0.0"
PORT = os.environ.get("PORT") or 9000

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST, PORT))
s.listen(9)

print("Server listening on port {}".format(PORT))  

def url_string(conn, addr):
    string = request.decode("UTF-8")

    data = string.encode("UTF-8")

    print("Request String:", data)

    first_line = string.split("\n")[0]
    print(first_line)
    url = first_line.split(" ")[1]
    
    is_post_request = False

    if(first_line.split(" ") [0] == "POST"):
        is_post_request = True

    http_pos = url.find("://")
    if(http_pos == -1):
        temp = url
    else:
        temp = url[(http_pos + 3):]

    port_pos = temp.find(":")

    webserver = ""
    port = -1

    path_pos = temp.find("/")
    path = ""
    if(path_pos == -1):
        path_pos = len(temp)
    else:
        path = temp[path_pos : len(temp)]


    if(port_pos == -1 or path_pos < port_pos):
        port = 80
        webserver = temp[:path_pos]
    else:
        port = int(temp[port_pos + 1 : len(temp)])
        webserver = temp[:port_pos]

    print(webserver + path, port)

    proxy_request(webserver=webserver + path, port=port)

def proxy_request(webserver, port):
    
    headers = get_HTTP_headers()

    data_recv = ""
    try:
        print("Proxying request to ", addr[0])
        if(port == 443):
            r = requests.get("https://" + webserver)
            data_recv = r.text
            send_headers_test()
            do_handshake()
        else:
            r = requests.get("http://" + webserver)
            data_recv = r.text
    
    except Exception as e:
        print(str(e))
        data_recv = str(e).encode()

    finally:
        print("finally block entered")
        merge_HTTP_headers_and_content(headers, data_recv)

import certifi

def do_handshake():
    ca_certificates = certifi.where()
    print("ca-certificate mozilla", ca_certificates)

    CIPHERS = 'ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:AES256-SHA'

    conn_s = ssl.wrap_socket(conn, ssl_version=ssl.PROTOCOL_TLS, cert_reqs=ssl.CERT_OPTIONAL, ca_certs=ca_certificates, do_handshake_on_connect=False)
    #conn_s = context.wrap_socket(conn, do_handshake_on_connect=False)

    print("Initiating Handshake!")
    conn_s.do_handshake()
    print("Handshake Completed!")


while True:

    conn, addr = s.accept()
    request = conn.recv(4704)
    print(request)

    thread = threading.Thread(target=url_string, args=(conn, addr))
    thread.setDaemon(True)
    thread.start()