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Análise de pacotes na prática [ Parte 8 ] - "TLS" - Raw Sockets python


Guest gnoo

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Saudações,

 

O intuito de fazer este script foi para ter uma ideia muito superficial de como funciona um TLS handshake, é de fazer notar que este script apenas analisa:

TLS Record 

Handshake

          Client Hello

           Server Hello

Application data 

 

Tudo o que envolve mensagens com certificados, necessita que seja dedicado um bom tempo de estudo, alguma dedicação ao assunto e eu não tenho esse tempo para dedicar a este tipo de assunto, e a vontade também não é muita.

Dito isto  digamos que o interesse aqui é ter um primeiro contato com TLS para tentar perceber como é feita a conversação entre o cliente e o servidor...

As fontes de informação para iniciantes numa primeira abordagem não são muitas, no entanto encontrei uma página em que o jovem que escreveu o artigo tentou fazer uma explicação que numa fase inicial é interessante, talvez haja outras fontes eu é que não encontrei.

Outra ferramenta que deve ser usada para complementar é o wireshark.

Traffic Analysis of an SSL/TLS Session

Pode ser encontrado aqui:

http://blog.fourthbit.com/2014/12/23/traffic-analysis-of-an-ssl-slash-tls-session

A informação que segue foi a que eu usei para criar o script, no link do site tem informação sobre outro tipo de mensagens.

2019-07-10_22-19.png.da3aa1be7a237f0d1eee0118769864cb.png

2019-07-10_22-21.png.e9d69aa9eef9915cef6701398785b5a1.png

 

2019-07-10_22-21_1.thumb.png.6a932e92e9e6d482d9d01e08f57b094b.png

 

2019-07-10_22-22.png.8f816e9f7a0f042fc011a47529442efb.png

2019-07-10_22-22_1.png.947fd49472215393a7021557845c33ce.png

 

 

2019-07-10_22-23.thumb.png.4c4fc7f1429f27e60cfaa7cfb4f5230d.png

 

 

2019-07-10_22-24.png.171ad529776b3c7ed15c5fc4e220be31.png

 

2019-07-10_22-27.png.bce3b9befac6e454e4b5648fea7f899b.png

NOTA Outros Links que podem ajudar:

https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/TLS_Cipher_String_Cheat_Sheet.md

https://www.ntu.edu.sg/home/ehchua/programming/webprogramming/http_ssl.html

https://www.cisco.com/c/en/us/support/docs/security-vpn/secure-socket-layer-ssl/116181-technote-product-00.html

 

OUTRA NOTA:

As cipher suites que estão no script que são usadas na negociação do Cliente Hello e Server Hello, algumas não são usadas mas qualquer das formas eu deixei lá, antes a mais do que a menos.

 

SCRIPT PYTHON

 

#coding:utf-8  
#!/usr/bin/env python3

from socket import *
import struct
import binascii

TIPO_RECORD = {22: "Handshake (22, 0x16)",
                 20: "Change Cipher Spec (20, 0x14)",
                 21: "Alert (21, 0x15)",
                 23: "Application Data (23, 0x17)"}

TLS_VERSAO = {768: "SSL 3.0 (0x0300)",
              769: "TLS 1.0 (0x0301)",
              770: "TLS 1.1 (0x0302)",
              771: "TLS 1.2 (0x0303)"}

TIPO_HANDSHAKE = {0: "HELLO_REQUEST (0) 0x00",
                   1: "CLIENT_HELLO  (1) 0x01",
                   2: "SERVER_HELLO  (2) 0x02",
                  11: "CERTIFICATE  (11) 0x0b",
                  12: "SERVER_KEY_EXCHANGE  (12) 0x0c",
                  13: "CERTIFICATE_REQUEST  (13) 0x0d",
                  14: "SERVER_DONE  (14) 0x0e",
                  15: "CERTIFICATE_VERIFY  (15) 0x0f",
                  16: "CLIENT_KEY_EXCHANGE (16) 0x10",
                  20: "FINISHED  (20) 0x14"}

# https://tools.ietf.org/html/rfc5246#page-75
 
# The following CipherSuite definitions require that the server provide
# an RSA certificate that can be used for key exchange.  The server may
# request any signature-capable certificate in the certificate request
# message.

TIPO_CIPHER_SUITE = {1: 'CipherSuite: TLS_RSA_WITH_NULL_MD5 (0x0001)',
                2: 'CipherSuite: TLS_RSA_WITH_NULL_SHA (0x0002)',
               59: 'CipherSuite: TLS_RSA_WITH_NULL_SHA256 (0x003B)',
                4: 'CipherSuite: TLS_RSA_WITH_RC4_128_MD5 (0x0004)',
                5: 'CipherSuite: TLS_RSA_WITH_RC4_128_SHA (0x0005)',
               10: 'CipherSuite: TLS_RSA_WITH_3DES_EDE_CBC_SHA (0x000A)',
               47: 'CipherSuite: TLS_RSA_WITH_AES_128_CBC_SHA (0x002F)',
               53: 'CipherSuite: TLS_RSA_WITH_AES_256_CBC_SHA (0x0035)',
               60: 'CipherSuite: TLS_RSA_WITH_AES_128_CBC_SHA256 (0x003C)',
               61: 'CipherSuite: TLS_RSA_WITH_AES_256_CBC_SHA256 (0x003D)',

# https://tools.ietf.org/html/rfc5246#page-75

# The following cipher suite definitions are used for server-
# authenticated (and optionally client-authenticated) Diffie-Hellman.
# DH denotes cipher suites in which the server's certificate contains
# the Diffie-Hellman parameters signed by the certificate authority
# (CA).  DHE denotes ephemeral Diffie-Hellman, where the Diffie-Hellman
# parameters are signed by a signature-capable certificate, which has
# been signed by the CA.  The signing algorithm used by the server is
# specified after the DHE component of the CipherSuite name.  The
# server can request any signature-capable certificate from the client
# for client authentication, or it may request a Diffie-Hellman
# certificate.  Any Diffie-Hellman certificate provided by the client
# must use the parameters (group and generator) described by the
# server.


               13: 'CipherSuite: TLS_DH_DSS_WITH_3DES_EDE_CBC_SHA (0x000D)',
               16: 'CipherSuite: TLS_DH_RSA_WITH_3DES_EDE_CBC_SHA (0x0010)',
               19: 'CipherSuite: TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA (0x0013)',
               22: 'CipherSuite: TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA (0x0016)',
               48: 'CipherSuite: TLS_DH_RSA_WITH_AES_128_CBC_SHA (0x0031)',
               50: 'CipherSuite: TLS_DHE_DSS_WITH_AES_128_CBC_SHA (0x0032)',
               51: 'CipherSuite: TLS_DHE_RSA_WITH_AES_128_CBC_SHA (0x0033)',
               54: 'CipherSuite: TLS_DH_DSS_WITH_AES_256_CBC_SHA (0x0036)',
               55: 'CipherSuite: TLS_DH_RSA_WITH_AES_256_CBC_SHA (0x0037)',
               56: 'CipherSuite: TLS_DHE_DSS_WITH_AES_256_CBC_SHA (0x0038)',
               57: 'CipherSuite:TLS_DHE_RSA_WITH_AES_256_CBC_SHA (0x0039)',
               62: 'CipherSuite: TLS_DH_DSS_WITH_AES_128_CBC_SHA256 (0x003E)',
               63: 'CipherSuite: TLS_DH_RSA_WITH_AES_128_CBC_SHA256 (0x003F)',
               64: 'CipherSuite: TLS_DHE_DSS_WITH_AES_128_CBC_SHA256 (0x0040)',
              103: 'CipherSuite: TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (0x0067)',
              104: 'CipherSuite: TLS_DH_DSS_WITH_AES_256_CBC_SHA256 (0x0068)',
              105: 'CipherSuite: TLS_DH_RSA_WITH_AES_256_CBC_SHA256 (0x0069)',
              106: 'CipherSuite: TLS_DHE_DSS_WITH_AES_256_CBC_SHA256 (0x006A)',
              107: 'CipherSuite: TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (0x006B)',

# https://tools.ietf.org/html/rfc5246#page-75  

# The following cipher suites are used for completely anonymous
# Diffie-Hellman communications in which neither party is
# authenticated.  Note that this mode is vulnerable to man-in-the-
# middle attacks.  Using this mode therefore is of limited use: These
# cipher suites MUST NOT be used by TLS 1.2 implementations unless the
# application layer has specifically requested to allow anonymous key
# exchange.  (Anonymous key exchange may sometimes be acceptable, for
# example, to support opportunistic encryption when no set-up for
# authentication is in place, or when TLS is used as part of more
# complex security protocols that have other means to ensure
# authentication.)
              
              24: 'CipherSuite: TLS_DH_anon_WITH_RC4_128_MD5 (0x0018)',
              27: 'CipherSuite: TLS_DH_anon_WITH_3DES_EDE_CBC_SHA (0x001B)',
              52: 'CipherSuite: TLS_DH_anon_WITH_AES_128_CBC_SHA (0x0034)',
              58: 'CipherSuite: TLS_DH_anon_WITH_AES_256_CBC_SHA (0x003A)',
             108: 'CipherSuite: TLS_DH_anon_WITH_AES_128_CBC_SHA256 (0x006C)',
             109: 'CipherSuite: TLS_DH_anon_WITH_AES_256_CBC_SHA256 (0x006D)',

# https://tools.ietf.org/html/rfc8446#page-133

# This specification defines the following cipher suites for use with TLS 1.3
                         
            4865: 'CipherSuite: TLS_AES_128_GCM_SHA256 (0x1301)',
            4866: 'CipherSuite: TLS_AES_256_GCM_SHA384 (0x1302)',
            4867: 'CipherSuite: TLS_CHACHA20_POLY1305_SHA256 (0x1303)',
            4868: 'CipherSuite: TLS_AES_128_CCM_SHA256 (0x1304)',
            4869: 'CipherSuite: TLS_AES_128_CCM_8_SHA256 (0x1305)',

# https://wiki.mozilla.org/Security/Server_Side_TLS#Cipher_names_correspondence_table

# Cipher preference: server chooses

# 0x13,0x01  -  TLS_AES_128_GCM_SHA256         TLSv1.3  Kx=any   Au=any    Enc=AESGCM(128)             Mac=AEAD
# 0x13,0x02  -  TLS_AES_256_GCM_SHA384         TLSv1.3  Kx=any   Au=any    Enc=AESGCM(256)             Mac=AEAD
# 0x13,0x03  -  TLS_CHACHA20_POLY1305_SHA256   TLSv1.3  Kx=any   Au=any    Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0xC0,0x2B  -  ECDHE-ECDSA-AES128-GCM-SHA256  TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=AESGCM(128)             Mac=AEAD
# 0xC0,0x2F  -  ECDHE-RSA-AES128-GCM-SHA256    TLSv1.2  Kx=ECDH  Au=RSA    Enc=AESGCM(128)             Mac=AEAD
# 0xC0,0x2C  -  ECDHE-ECDSA-AES256-GCM-SHA384  TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=AESGCM(256)             Mac=AEAD
# 0xC0,0x30  -  ECDHE-RSA-AES256-GCM-SHA384    TLSv1.2  Kx=ECDH  Au=RSA    Enc=AESGCM(256)             Mac=AEAD
# 0xCC,0xA9  -  ECDHE-ECDSA-CHACHA20-POLY1305  TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0xCC,0xA8  -  ECDHE-RSA-CHACHA20-POLY1305    TLSv1.2  Kx=ECDH  Au=RSA    Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0x00,0x9E  -  DHE-RSA-AES128-GCM-SHA256      TLSv1.2  Kx=DH    Au=RSA    Enc=AESGCM(128)             Mac=AEAD
# 0x00,0x9F  -  DHE-RSA-AES256-GCM-SHA384      TLSv1.2  Kx=DH    Au=RSA    Enc=AESGCM(256)             Mac=AEAD
# 0xCC,0xAA  -  DHE-RSA-CHACHA20-POLY1305      TLSv1.2  Kx=DH    Au=RSA    Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0xC0,0x23  -  ECDHE-ECDSA-AES128-SHA256      TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=AES(128)                Mac=SHA256
# 0xC0,0x27  -  ECDHE-RSA-AES128-SHA256        TLSv1.2  Kx=ECDH  Au=RSA    Enc=AES(128)                Mac=SHA256
# 0xC0,0x09  -  ECDHE-ECDSA-AES128-SHA         TLSv1    Kx=ECDH  Au=ECDSA  Enc=AES(128)                Mac=SHA1
# 0xC0,0x13  -  ECDHE-RSA-AES128-SHA           TLSv1    Kx=ECDH  Au=RSA    Enc=AES(128)                Mac=SHA1
# 0xC0,0x24  -  ECDHE-ECDSA-AES256-SHA384      TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=AES(256)                Mac=SHA384
# 0xC0,0x28  -  ECDHE-RSA-AES256-SHA384        TLSv1.2  Kx=ECDH  Au=RSA    Enc=AES(256)                Mac=SHA384
# 0xC0,0x0A  -  ECDHE-ECDSA-AES256-SHA         TLSv1    Kx=ECDH  Au=ECDSA  Enc=AES(256)                Mac=SHA1
# 0xC0,0x14  -  ECDHE-RSA-AES256-SHA           TLSv1    Kx=ECDH  Au=RSA    Enc=AES(256)                Mac=SHA1
# 0x00,0x67  -  DHE-RSA-AES128-SHA256          TLSv1.2  Kx=DH    Au=RSA    Enc=AES(128)                Mac=SHA256
# 0x00,0x6B  -  DHE-RSA-AES256-SHA256          TLSv1.2  Kx=DH    Au=RSA    Enc=AES(256)                Mac=SHA256
# 0x00,0x9C  -  AES128-GCM-SHA256              TLSv1.2  Kx=RSA   Au=RSA    Enc=AESGCM(128)             Mac=AEAD
# 0x00,0x9D  -  AES256-GCM-SHA384              TLSv1.2  Kx=RSA   Au=RSA    Enc=AESGCM(256)             Mac=AEAD
# 0x00,0x3C  -  AES128-SHA256                  TLSv1.2  Kx=RSA   Au=RSA    Enc=AES(128)                Mac=SHA256
# 0x00,0x3D  -  AES256-SHA256                  TLSv1.2  Kx=RSA   Au=RSA    Enc=AES(256)    

#Cipher preference: client chooses

# 0x13,0x01  -  TLS_AES_128_GCM_SHA256         TLSv1.3  Kx=any   Au=any    Enc=AESGCM(128)             Mac=AEAD
# 0x13,0x02  -  TLS_AES_256_GCM_SHA384         TLSv1.3  Kx=any   Au=any    Enc=AESGCM(256)             Mac=AEAD
# 0x13,0x03  -  TLS_CHACHA20_POLY1305_SHA256   TLSv1.3  Kx=any   Au=any    Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0xC0,0x2B  -  ECDHE-ECDSA-AES128-GCM-SHA256  TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=AESGCM(128)             Mac=AEAD
# 0xC0,0x2F  -  ECDHE-RSA-AES128-GCM-SHA256    TLSv1.2  Kx=ECDH  Au=RSA    Enc=AESGCM(128)             Mac=AEAD
# 0xC0,0x2C  -  ECDHE-ECDSA-AES256-GCM-SHA384  TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=AESGCM(256)             Mac=AEAD
# 0xC0,0x30  -  ECDHE-RSA-AES256-GCM-SHA384    TLSv1.2  Kx=ECDH  Au=RSA    Enc=AESGCM(256)             Mac=AEAD
# 0xCC,0xA9  -  ECDHE-ECDSA-CHACHA20-POLY1305  TLSv1.2  Kx=ECDH  Au=ECDSA  Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0xCC,0xA8  -  ECDHE-RSA-CHACHA20-POLY1305    TLSv1.2  Kx=ECDH  Au=RSA    Enc=CHACHA20/POLY1305(256)  Mac=AEAD
# 0x00,0x9E  -  DHE-RSA-AES128-GCM-SHA256      TLSv1.2  Kx=DH    Au=RSA    Enc=AESGCM(128)             Mac=AEAD
# 0x00,0x9F  -  DHE-RSA-AES256-GCM-SHA384      TLSv1.2  Kx=DH    Au=RSA    Enc=AESGCM(256)             Mac=AEAD

          49195: 'CipherSuite: ECDHE-ECDSA-AES128-GCM-SHA256 (0xc02B)',
          49199: 'CipherSuite: ECDHE-RSA-AES128-GCM-SHA256 (0xc02f)',
          49196: 'CipherSuite: ECDHE-ECDSA-AES256-GCM-SHA384 (0xc02c)',
          49200: 'CipherSuite: ECDHE-RSA-AES256-GCM-SHA384 (0xc030)',
          52393: 'CipherSuite: ECDHE-ECDSA-CHACHA20-POLY1305 (0xccA9)',
          52392: 'CipherSuite: ECDHE-RSA-CHACHA20-POLY1305 (0xcca8)',
            158: 'CipherSuite: DHE-RSA-AES128-GCM-SHA256 (0x009e)',
            159: 'CipherSuite: DHE-RSA-AES256-GCM-SHA384 (0x009f)',
          52394: 'CipherSuite: DHE-RSA-CHACHA20-POLY1305 (0xccaa)',
          49187: 'CipherSuite: ECDHE-ECDSA-AES128-SHA256 (0xc023)',
          49191: 'CipherSuite: ECDHE-RSA-AES128-SHA256 (0xc027)',
          49161: 'CipherSuite: ECDHE-ECDSA-AES128-SHA (0xc009)',
          49188: 'CipherSuite: ECDHE-ECDSA-AES256-SHA384 (0xc024)',
          49171: 'CipherSuite: ECDHE-RSA-AES128-SHA (0xc013)',
          49192: 'CipherSuite: ECDHE-RSA-AES256-SHA384 (0xc028)',
          49162: 'CipherSuite: ECDHE-ECDSA-AES256-SHA (0xc00a)',
          49172: 'CipherSuite: ECDHE-RSA-AES256-SHA (0xc014)',
            156: 'CipherSuite: AES128-GCM-SHA256 (0x009c)',
            157: 'CipherSuite: AES256-GCM-SHA384 (0x009d)',

# https://tools.ietf.org/html/draft-davidben-tls-grease-00

#GREASE Values

# This document reserves a number of TLS protocol values, referred to
# as GREASE values.  These values were allocated sparsely to discourage
# server implementations from conditioning on them.  For convenience,
# they were also chosen so all types share a number scheme with a
# consistent pattern while avoiding collisions with any existing
# applicable registries in TLS.

#The following values are reserved as both GREASE extension values and

#GREASE named group values:

#      2570 (0x0A0A)
#      6682 (0x1A1A)
#      10794 (0x2A2A)
#      14906 (0x3A3A)
#      19018 (0x4A4A)
#      23130 (0x5A5A)
#      27242 (0x6A6A)
#      31354 (0x7A7A)
#      35466 (0x8A8A)
#      39578 (0x9A9A)
#      43690 (0xAAAA)
#      47802 (0xBABA)
#      51914 (0xCACA)
#      56026 (0xDADA)
#      60138 (0xEAEA)
#      64250 (0xFAFA)

          23130: 'CipherSuite: Reserved (GREASE) (0x5a5a)',
           2570: 'CipherSuite: Reserved (GREASE) (0x0a0a)',
           6682: 'CipherSuite: Reserved (GREASE) (0x1a1a)',
          10794: 'CipherSuite: Reserved (GREASE) (0x2a2a)',
          14906: 'CipherSuite: Reserved (GREASE) (0x3a3a)',
          19018: 'CipherSuite: Reserved (GREASE) (0x4a4a)',
          23130: 'CipherSuite: Reserved (GREASE) (0x5a5a)',
          27242: 'CipherSuite: Reserved (GREASE) (0x6a6a)',
          31354: 'CipherSuite: Reserved (GREASE) (0x7a7a)',
          35466: 'CipherSuite: Reserved (GREASE) (0x8a8a)',
          39578: 'CipherSuite: Reserved (GREASE) (0x9a9a)',
          43690: 'CipherSuite: Reserved (GREASE) (0xaaaa)',
          47802: 'CipherSuite: Reserved (GREASE) (0xbaba)',
          51914: 'CipherSuite: Reserved (GREASE) (0xcaca)',
          56026: 'CipherSuite: Reserved (GREASE) (0xdada)',
          60138: 'CipherSuite: Reserved (GREASE) (0xeaea)',
          64250: 'CipherSuite: Reserved (GREASE) (0xfafa)'}

def ethernet_frame(raw_dados):
    mac_destino, mac_fonte, protocolo = struct.unpack('! 6s 6s H', raw_dados[:14])

    return byte_to_hex_mac(mac_destino), byte_to_hex_mac(mac_fonte), htons(protocolo), raw_dados[14:]




def byte_to_hex_mac(mac_em_bytes):
    endereco = binascii.hexlify(mac_em_bytes).decode("ascii")
    return ":".join([endereco[i:i+2] for i in range(0,12,2)])


def dados_pacote_ipv4(payload_frame):
    tupla_dados_ipv4 = struct.unpack("!BBHHHBBH4s4s", payload_frame[:20])
    versao_e_HLEN = tupla_dados_ipv4[0]
    tamanho_header = (versao_e_HLEN & 15) * 4
    versao = versao_e_HLEN >> 4
    tipo_servico = tupla_dados_ipv4[1]
    tamanho_total = tupla_dados_ipv4[2]
    identificacao = tupla_dados_ipv4[3]
    offset_fragmento = tupla_dados_ipv4[4]
    tempo_vida_ttl = tupla_dados_ipv4[5]
    protocolos = tupla_dados_ipv4[6]
    checksum_cabecalho = tupla_dados_ipv4[7]
    ip_origem = inet_ntoa(tupla_dados_ipv4[8])
    ip_destino = inet_ntoa(tupla_dados_ipv4[9])
  

    dados_ipv4_header = {'IPv4 Orivgem':ip_origem, 'IPv4 Destino':ip_destino, 'Protocolo': protocolos, 'Payload_ipv4': payload_frame[20:]}  
    
    return dados_ipv4_header

def dados_pacote_tcp(payload_ipv4):
    tupla_dados_tcp = struct.unpack('! HHLLBBHHH', payload_ipv4[:20])
    porta_fonte = tupla_dados_tcp[0]
    porta_destino = tupla_dados_tcp[1]
    numero_sequencia = tupla_dados_tcp[2]
    numero_confirmacao = tupla_dados_tcp[3]

    # recebe dois campos do cabeçalho ( HLEN & RESERVADO )
    hlen_e_reservado = tupla_dados_tcp[4]

    # recebe campo HLEN 
    header_len = (hlen_e_reservado >> 4) * 4
    
    flags = tupla_dados_tcp[5]
    flag_FIN = flags & 1
    flag_SYN = (flags >> 1) & 1
    flag_RST = (flags >> 2) & 1
    flag_PSH = (flags >> 3) & 1
    flag_ACK = (flags >> 4) & 1
    flag_URG = (flags >> 5) & 1
    flag_ECE = (flags >> 6) & 1
    flag_CWR = (flags >> 7) & 1

    window_size = tupla_dados_tcp[6]
    checksum = tupla_dados_tcp[7]
    urgent_pointer = tupla_dados_tcp[8]

    dados_tcp_header = {'Porta_Fonte':porta_fonte, 'Porta_Destino':porta_destino, 
                        'checksum':checksum,'Payload_TCP': payload_ipv4[20:]}

    return dados_tcp_header

def formato_tls_record(dados_tcp_payload):
    """
    http://blog.fourthbit.com/2014/12/23/traffic-analysis-of-an-ssl-slash-tls-session
    """
    TLS_RECORD_TYPE, TLS_VERSION, TLS_LENGTH, TESTE_HANDSHAKE_TYPE = struct.unpack('!BHHB', dados_tcp_payload[:6])
 
    return TLS_RECORD_TYPE, TLS_VERSION, TLS_LENGTH, TESTE_HANDSHAKE_TYPE

def formato_tls_hello_client(dados_tcp_payload):
    """
        int.from_bytes(LENGTH_OBJ_BYTES, byteorder='big'), faz type casting ( conversão do tipo de dados), byte object para decimal,
        é necessário usar este método uma vez que o tamanho do campo Length são 3 bytes e o unpack não consegue desempacotar 
        esse tamanho.
        Ver documentação:
        https://docs.python.org/3/library/stdtypes.htmler
    """
    lista_cipher_suites = []

    HandshakeType = dados_tcp_payload[5:]
    HANDSHAKE_TYPE, = struct.unpack("!B", HandshakeType[:1])
    LENGTH_OBJ_BYTES = HandshakeType[1:4]
    LENGHT_DECIMAL = int.from_bytes(LENGTH_OBJ_BYTES, byteorder='big')
    VERSION, = struct.unpack('!H', HandshakeType[4:6])
    RANDOM_32BITS = HandshakeType[6:38]
    HEX_RANDOM_32BITS = binascii.hexlify(RANDOM_32BITS).decode()
    SESSION_ID_LENGTH, = struct.unpack("!B",HandshakeType[38:39])
    SESSION_ID = HandshakeType[39: 39 + SESSION_ID_LENGTH]
    HEX_SESSION_ID = binascii.hexlify(SESSION_ID).decode()
    CIPHER_SUITES_LENGTH, = struct.unpack("!H", HandshakeType[39 + SESSION_ID_LENGTH : 39 + SESSION_ID_LENGTH + 2])
    ARRAY_OBJETO_BYTES_CIPHER_SUITES = HandshakeType[39 + SESSION_ID_LENGTH + 2 : 39 + SESSION_ID_LENGTH + 2 + CIPHER_SUITES_LENGTH]
    
    index = 2
    while len(ARRAY_OBJETO_BYTES_CIPHER_SUITES) != 0:
        cipher_suite, = struct.unpack('!H', ARRAY_OBJETO_BYTES_CIPHER_SUITES[:index])
        lista_cipher_suites.append(cipher_suite)
        ARRAY_OBJETO_BYTES_CIPHER_SUITES = ARRAY_OBJETO_BYTES_CIPHER_SUITES[index:]
    
    return HANDSHAKE_TYPE, LENGHT_DECIMAL, VERSION, HEX_RANDOM_32BITS, SESSION_ID_LENGTH, HEX_SESSION_ID, + \
           CIPHER_SUITES_LENGTH, ARRAY_OBJETO_BYTES_CIPHER_SUITES, lista_cipher_suites

def formato_tls_hello_server(dados_tcp_payload):
    """
        int.from_bytes(LENGTH_OBJ_BYTES, byteorder='big'), faz type casting ( conversão do tipo de dados), byte object para decimal,
        é necessário usar este método uma vez que o tamanho do campo Length são 3 bytes e o unpack não consegue desempacotar 
        esse tamanho.
        Ver documentação:
        https://docs.python.org/3/library/stdtypes.htmler
    """
    
    HandshakeType = dados_tcp_payload[5:]
    HANDSHAKE_TYPE, = struct.unpack("!B", HandshakeType[:1])
    LENGTH_OBJ_BYTES = HandshakeType[1:4]
    LENGHT_DECIMAL = int.from_bytes(LENGTH_OBJ_BYTES, byteorder='big')
    VERSION, = struct.unpack('!H', HandshakeType[4:6])
    RANDOM_32BITS = HandshakeType[6:38]
    HEX_RANDOM_32BITS = binascii.hexlify(RANDOM_32BITS).decode()
    SESSION_ID_LENGTH, = struct.unpack("!B",HandshakeType[38:39])
    
    if SESSION_ID_LENGTH > 0:
        SESSION_ID = HandshakeType[39: 39 + SESSION_ID_LENGTH]
        HEX_SESSION_ID = binascii.hexlify(SESSION_ID).decode()
        # Cipher suites só contém apenas uma ( analisar 2 bytes)
        #OBJETO_BYTES_CIPHER_SUITES = HandshakeType[39 + SESSION_ID_LENGTH : 39 + SESSION_ID_LENGTH + 2]
        CIPHER_SUITE, = struct.unpack('!H', HandshakeType[39 + SESSION_ID_LENGTH : 39 + SESSION_ID_LENGTH + 2])
        
        return HANDSHAKE_TYPE, LENGHT_DECIMAL, VERSION, HEX_RANDOM_32BITS, SESSION_ID_LENGTH, HEX_SESSION_ID, CIPHER_SUITE
    else:
        pass

def formato_application_data(dados_tcp_payload):
    TYPE, VERSION, LENGTH = struct.unpack('!BHH', dados_tcp_payload[:5])
    BYTES_OBJ_ENCRYPTED_APPLICATION_DATA = dados_tcp_payload [5: 5 + LENGTH]
    HEX_ENCRYPTED_APPLICATION_DATA = binascii.hexlify(BYTES_OBJ_ENCRYPTED_APPLICATION_DATA)
    
    return TYPE, VERSION, LENGTH, HEX_ENCRYPTED_APPLICATION_DATA



sock = socket(AF_PACKET, SOCK_RAW, ntohs(0x0003))    

while True:
    raw_dados, addr = sock.recvfrom(65536)
    mac_destino, mac_fonte, ethernet_type, payload = ethernet_frame(raw_dados)

    # Se for 8 vem ai pacote IP \0/
    if ethernet_type == 8:
        dados_ipv4_header = dados_pacote_ipv4(payload)

        if dados_ipv4_header['Protocolo'] == 6:
            dados_tcp_header = dados_pacote_tcp(dados_ipv4_header['Payload_ipv4'])
            if dados_tcp_header['Porta_Fonte'] == 443 or dados_tcp_header['Porta_Destino'] == 443:
                if dados_tcp_header['Payload_TCP']:
                    tls_record_type, tls_version, tls_length, teste_handshake_type = formato_tls_record(dados_tcp_header['Payload_TCP'])
                    if tls_record_type in TIPO_RECORD.keys() and tls_version in TLS_VERSAO.keys():
                        if tls_record_type == 22:
                            print("##### TCP PAYLOAD (TLS) #####\n")
                            print("TCP Checksum: {}".format(dados_tcp_header['checksum']))
                            print("TIPO: {}".format(TIPO_RECORD[tls_record_type]))
                            print("VERSÃO: {}".format(TLS_VERSAO[tls_version]))
                            print("LENGTH: {}".format(tls_length))
                            if teste_handshake_type == 1:
                                (HShake_type, HShake_length, HShake_version, HShake_random_32bit, HShake_session_id_length,
                                 HShake_session_id, HShake_cipher_suites_length, HShake_array_ob_bytes_cipher_suites, 
                                 HShake_lista_cipher_suites) = formato_tls_hello_client(dados_tcp_header['Payload_TCP'])
        
                                print("#####(TLS) HANDSHAKE PROTOCOL #####")
                                print("TIPO: {}".format(TIPO_HANDSHAKE[HShake_type]))
                                print("LENGTH: {}".format(HShake_length))
                                print("VERSÃO: {}".format(TLS_VERSAO[HShake_version]))
                                print("32-bit Random: {}".format((HShake_random_32bit)))
                                print("Session id length: {}".format(HShake_session_id_length))
                                print("session id: {}".format(HShake_session_id))
                                print("Cipher suites length: {}".format(HShake_cipher_suites_length))
                                print("Cipher Suites({})".format(len(HShake_lista_cipher_suites)))
                                for C_Suite in HShake_lista_cipher_suites:
                                    if C_Suite in TIPO_CIPHER_SUITE.keys():
                                        print(TIPO_CIPHER_SUITE[C_Suite])
                                    else: 
                                        print(C_Suite)
                            
                            elif teste_handshake_type == 2:
                                (HShake_type, HShake_length, HShake_version, HShake_random_32bit, HShake_session_id_length,
                                 HShake_session_id, HShake_cipher_suite) = formato_tls_hello_server(dados_tcp_header['Payload_TCP'])
                                print("#####(TLS) HANDSHAKE PROTOCOL #####")
                                print("TIPO: {}".format(TIPO_HANDSHAKE[HShake_type]))
                                print("LENGTH: {}".format(HShake_length))
                                print("VERSÃO: {}".format(TLS_VERSAO[HShake_version]))
                                print("32-bit Random: {}".format((HShake_random_32bit)))
                                print("Session id length: {}".format(HShake_session_id_length))
                                print("session id: {}".format(HShake_session_id))
                                print("{}".format(TIPO_CIPHER_SUITE[HShake_cipher_suite]))
                        
                        elif tls_record_type == 23:
                            print("#### APPLICATION DATA ####")
                            (application_data_type, application_data_version,
                             application_data_length, hex_application_data_encripted)=formato_application_data(dados_tcp_header['Payload_TCP'])
                            
                            print("Type: {}".format(application_data_type))
                            print("Version: {}".format(TLS_VERSAO[application_data_version]))
                            print("Length: {}".format(application_data_length))
                            print("Encrypted Application Data: {}".format(hex_application_data_encripted))


                    

 

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