- fix dissection of stacked tlsrecords within SSL()

[tintinweb]

@alexmgr does this fix problems with stacked records for you? if so, we can also fix this by having scapy dissect our packets by implementing extract_padding on TLSRecord.

Note that packets after the change_cipher_spec are encrypted. We do not handle this at the moment thats why the packet after change_cipher_spec looks odd. Need to implement that on a TLSRecord level to fall back to Raw or a special TLSEncrypted layer in case the payload to TLSRecord carries an invalid length.

this is what I get with python2.6 on that branch, trying to process a recorded handshake tls1_0 aes128-sha (openssl s_client/s_server):

test code:

pcaps = rdpcap(r'ssl.pcap')
for p in pcaps:
    if p.haslayer(SSL):
        p[TCP].show2()

output:

WARNING: No route found for IPv6 destination :: (no default route?)
###[ TCP ]###
  sport     = 12046
  dport     = https
  seq       = 627883325
  ack       = 3436110327L
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 65535
  chksum    = 0x7caf
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0xd1
      |###[ TLS Handshake ]###
      |     type      = client_hello
      |     length    = 0xcd
      |###[ TLS Client Hello ]###
      |        version   = TLS_1_0
      |        gmt_unix_time= 4288841879L
      |        random_bytes= '|A\xa1\x084,\x98\xc2p\x04\xa0]_9\xef\xe0p\xd5\x12\xf15\x17\xb6\r\xc4\xd3\t\x85'
      |        session_id_length= 0x0
      |        session_id= ''
      |        cipher_suites_length= 0x5a
      |        cipher_suites= [49172, 49162, 57, 56, 136, 135, 49167, 49157, 53, 132, 49171, 49161, 51, 50, 154, 153, 69, 68, 49166, 49156, 47, 150, 65, 49169, 49159, 49164, 49154, 5, 4, 49170, 49160, 22, 19, 49165, 49155, 10, 21, 18, 9, 20, 17, 8, 6, 3, 255]
      |        compression_methods_length= 0x2
      |        compression_methods= [1, 0]
      |        extensions_length= 0x49
      |        \extensions\
      |         |###[ TLS Extension ]###
      |         |  type      = ec_point_formats
      |         |  length    = 0x4
      |         |###[ TLS Extension EC Points Format ]###
      |         |     length    = 0x3
      |         |     ec_point_formats= [0, 1, 2]
      |         |###[ TLS Extension ]###
      |         |  type      = elliptic_curves
      |         |  length    = 0x34
      |         |###[ TLS Extension Elliptic Curves ]###
      |         |     length    = 0x32
      |         |     elliptic_curves= [14, 13, 25, 11, 12, 24, 9, 10, 22, 23, 8, 6, 7, 20, 21, 4, 5, 18, 19, 1, 2, 3, 15, 16, 17]
      |         |###[ TLS Extension ]###
      |         |  type      = session_ticket_tls
      |         |  length    = 0x0
      |         |###[ TLS Extension ]###
      |         |  type      = heartbeat
      |         |  length    = 0x1
      |         |###[ TLS Extension HeartBeat ]###
      |         |     mode      = '\x01'
###[ TCP ]###
  sport     = https
  dport     = 12046
  seq       = 3436110327L
  ack       = 627883539
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 123
  chksum    = 0xe52e
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0x3a
      |###[ TLS Handshake ]###
      |     type      = server_hello
      |     length    = 0x36
      |###[ TLS Server Hello ]###
      |        version   = TLS_1_0
      |        gmt_unix_time= 1432147607
      |        random_bytes= '\xa3\x97\xe9\xf4\x0c\xf4V\x14\x9f\xe4$\xf9\xebI\xd4\xd1_\xfc\x12\xb4\xfdEN=\xebj\xad\xcf'
      |        session_id_length= 0x0
      |        session_id= ''
      |        cipher_suite= RSA_WITH_AES_128_CBC_SHA
      |        compression_method= DEFLATE
      |        extensions_length= 0xe
      |        \extensions\
      |         |###[ TLS Extension ]###
      |         |  type      = renegotiationg_info
      |         |  length    = 0x1
      |         |###[ Raw ]###
      |         |     load      = '\x00'
      |         |###[ TLS Extension ]###
      |         |  type      = session_ticket_tls
      |         |  length    = 0x0
      |         |###[ TLS Extension ]###
      |         |  type      = heartbeat
      |         |  length    = 0x1
      |         |###[ TLS Extension HeartBeat ]###
      |         |     mode      = '\x01'
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0x190
      |###[ TLS Handshake ]###
      |     type      = certificate
      |     length    = 0x18c
      |###[ TLS Certificate List ]###
      |        length    = 0x189
      |        \certificates\
      |         |###[ TLS Certificate ]###
      |         |  length    = 0x186
      |         |  \data      \
      |         |   |###[ X509Cert ]###
      |         |   |  version   = None
      |         |   |  sn        = <ASN1_INTEGER[4L]>
      |         |   |  sign_algo = <ASN1_OID['.1.2.840.113549.1.1.4']>
      |         |   |  sa_value  = <ASN1_NULL[0L]>
      |         |   |  \issuer    \
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.6']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['AU']>
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.8']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['QLD']>
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.3']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['SSLeay/rsa test CA']>
      |         |   |  not_before= <ASN1_UTC_TIME['951009233205Z']>
      |         |   |  not_after = <ASN1_UTC_TIME['980705233205Z']>
      |         |   |  \subject   \
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.6']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['AU']>
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.8']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['QLD']>
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.10']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['Mincom Pty. Ltd.']>
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.11']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['CS']>
      |         |   |   |###[ X509RDN ]###
      |         |   |   |  oid       = <ASN1_OID['.2.5.4.3']>
      |         |   |   |  value     = <ASN1_PRINTABLE_STRING['SSLeay demo server']>
      |         |   |  pubkey_algo= <ASN1_OID['.1.2.840.113549.1.1.1']>
      |         |   |  pk_value  = <ASN1_NULL[0L]>
      |         |   |  pubkey    = <ASN1_BIT_STRING['\x000H\x02A\x00\xb7,%\xdcI\xc5\xaekC\xc5.A\xc1.m\x95z:\xa9\x03QxE\x0f*\xd1X\xd1\x88\xf6\x9f\x8f\x1f\xd9\xfd\xa5\x87\xde*]1[\xee$f\xbf\xc0U\xdb\xfep\xc5,9_Z\x9f\xa8\x08\xfc!\x06\xd5O\x02\x03\x01\x00\x01']>
      |         |   |  x509v3ext = []
      |         |   |  sign_algo2= <ASN1_OID['.1.2.840.113549.1.1.4']>
      |         |   |  sa2_value = <ASN1_NULL[0L]>
      |         |   |  signature = <ASN1_BIT_STRING['\x00+4["\x85b#\x076\xf4\x0c+\x14\xd0\x1b\xcb\xd9\xbb\xd2\xc0\x9a\xcf\x12\xa1e\x90:\xb7\x17\x83:\x10k\xad/\xd6\xb1\x11\xc0\rZ\x06\xdb\x11\xd0/4\x90\xf5va&\xa1i\xf2\xdb\xb3\xe7 \xcb:d\xe6A']>
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0x4
      |###[ TLS Handshake ]###
      |     type      = server_hello_done
      |     length    = 0x0
###[ TCP ]###
  sport     = 12046
  dport     = https
  seq       = 627883539
  ack       = 3436110804L
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 65058
  chksum    = 0xac08
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0x46
      |###[ TLS Handshake ]###
      |     type      = client_key_exchange
      |     length    = 0x42
      |###[ TLS Client Key Exchange ]###
      |        length    = 0x40
      |###[ Raw ]###
      |           load      = '\x9es\xdf\xe0\xf2\xd0@2D\x9a4\x7fW\x86\x10\xea=\xc5\xe2\xf9\xa5iC\xc9\x0b\x00~\x911W\xfc\xc5e\x18\rD\xfdQ\xf8\xda\x8az\xab\x16\x03\xeb\xac#n\x8d\xdd\xbb\xf4u\xe7\xb7\xa3\xce\xdbgk}0*'
      |###[ TLS Record ]###
      |  content_type= change_cipher_spec
      |  version   = TLS_1_0
      |  length    = 0x1
      |###[ TLS ChangeCipherSpec ]###
      |     message   = '\x01'
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0x30
      |###[ TLS Handshake ]###
      |     type      = certificate_url
      |     length    = 0xcb7a5b
      |###[ Raw ]###
      |        load      = "-\xc0'\t(b\x95D\x9f\xa1\x1eNj\xfbI\x9dj$D\xc6\x8e&\xbc\xc1(\x8c'\xcc\xa2\xba\xec8cnd\xd8R\x94\x17\x96a\xfd\x9cT"
###[ TCP ]###
  sport     = https
  dport     = 12046
  seq       = 3436110804L
  ack       = 627883673
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 131
  chksum    = 0xc77f
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0xaa
      |###[ TLS Handshake ]###
      |     type      = 4
      |     length    = 0xa6
      |###[ Raw ]###
      |        load      = '\x00\x00\x1c \x00\xa0\xd4\xee\xb0\x9b\xb5\xa2\xd3\x00W\x84Y\xec\r\xbf\x05\x0c\xd5\xb9\xe2\xf82\xb5\xec\xce\xe2\x9c%%\xd9>J\x94[\xca\x18+\x0f_\xf6s8b\xcd\xcc\xf129\xe4^0\xf3\x94\xf5\xc5\x94:\x8c\x8e\xe5\x12J\x1e\xd81\xb5\x17\t\xa6Li\xca\xae\xfb\x04\x17dT\x9e\xc2\xfa\xf3m\xe9\xa5\xed\xa6e\xfe/\xf3\xc6\xcex@\xf7e\xe0\x13\xd3w\xc7\xc5y\x16VL0\x94\xcf\xb0<\x00\x91\xbd\x86\x08\x9f/\x05g\x03o\xa7;\xb96\xf2\x80O`]L\xc4B]\x02D\xba1\x8f9\x8e\x0c\x1e\xa8&O>\x01\x96\xb3o\xc6%\xe40\x03\xd6:}'
      |###[ TLS Record ]###
      |  content_type= change_cipher_spec
      |  version   = TLS_1_0
      |  length    = 0x1
      |###[ TLS ChangeCipherSpec ]###
      |     message   = '\x01'
      |###[ TLS Record ]###
      |  content_type= handshake
      |  version   = TLS_1_0
      |  length    = 0x30
      |###[ TLS Handshake ]###
      |     type      = 37
      |     length    = 0xb858c1
      |###[ Raw ]###
      |        load      = '\xa6?\xf8\xbd\xe6\xae\xbd\x98\xd4u\xa5E\x1b\xd8jpy\x86)NOd\xba\xe7\x1f\xcaK\x96\x9b\xf7\x0bP\xf5O\xfd\xda\xda\xcd\xcdK\x12.\xdf\xd5'
###[ TCP ]###
  sport     = 12046
  dport     = https
  seq       = 627883673
  ack       = 3436111038L
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 64824
  chksum    = 0xf6a8
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= application_data
      |  version   = TLS_1_0
      |  length    = 0x20
      |###[ Raw ]###
      |     load      = 'j=\xd7c\x08\x89\xd2g\t\xc6\xe7\xfdT0\xd1\xbbg\xb4 \xd0<}}</\xb7\x1a\t\xcbve$'
      |###[ TLS Record ]###
      |  content_type= application_data
      |  version   = TLS_1_0
      |  length    = 0x20
      |###[ Raw ]###
      |     load      = '-\xaa\xf59\xd02\xea\x88\x99&F\xdar\xafAk\x83M\x84\xe7\xe7\xa6\xde\xdd\xbdz\xa3\x98\xbe\x11D\xa7'
###[ TCP ]###
  sport     = 12046
  dport     = https
  seq       = 627883747
  ack       = 3436111038L
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 64824
  chksum    = 0x67f8
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= application_data
      |  version   = TLS_1_0
      |  length    = 0x20
      |###[ Raw ]###
      |     load      = 'w:\x94}\xb4GJ\x1d\xd4lZit\x03\x932\xcaT^\xa5\x81\x99jsf\xbf\x06\xa0\xdcj\x9c\xb1'
      |###[ TLS Record ]###
      |  content_type= application_data
      |  version   = TLS_1_0
      |  length    = 0x20
      |###[ Raw ]###
      |     load      = 'Dd\xc8\xc2Z\xfcJ\x82\xddSm0\x82M5"\xf1_;\x96fya\x9fQ\x93\x1b\xbfS;\xf8&'
###[ TCP ]###
  sport     = 12046
  dport     = https
  seq       = 627883821
  ack       = 3436111038L
  dataofs   = 5L
  reserved  = 0L
  flags     = PA
  window    = 64824
  chksum    = 0x5a0b
  urgptr    = 0
  options   = []
###[ SSL/TLS ]###
     \records   \
      |###[ TLS Record ]###
      |  content_type= application_data
      |  version   = TLS_1_0
      |  length    = 0x20
      |###[ Raw ]###
      |     load      = '\x89\xa0\x89`Hp\x03W\xd0?x^~CxNtBM\x15\x02\xe0\x0eom[\x11\x08\x96\xd3z\xe6'
      |###[ TLS Record ]###
      |  content_type= application_data
      |  version   = TLS_1_0
      |  length    = 0x30
      |###[ Raw ]###
      |     load      = '-d\xb0#\x1a\xa8\x10\\c\xec\xd3Mh\xe3\xdaS\xe60@\xf4\xc2\xffw\xd8+\xf6,x\xf7?+\xa5\x1c\xb32\xd8w\xdd\xb1{\x91u\xf0\xae\x14\xa8\xef\x1b'

[alexmgr]

I'll give it a shot, but I doubt it will fix it, because that was one of the first fixes I tried on that code branch. Also this will not fix the optional extensions problem. we can also fix this by having scapy dissect our packets by implementing extract_padding on TLSRecord. => This is roughly what I did in PR#16, but it also deals with optional extensions and removes the dead code in do_dissect() I'll check it out and let you know.

[tintinweb]

Oh, you're right, seems like extensions are optional to hello packets! Totally skipped that part while going through the RFC.

will close this one. please go ahead and merge #17, thanks!