Merge tests and tweaks with existing EAPOL_KEY class

Added EAPOL-Key layer according to IEEE 802.11-2016 standard. Layer
includes helper function for guessing 4-way handshake key number.

scapy/layers/eap.py

@@ -438,6 +438,10 @@ class LEAP(EAP):
 
 class EAPOL_KEY(Packet):
     name = "EAPOL_KEY"
+    deprecated_fields = {
+        "key": ("key_data", "2.6.0"),
+        "len": ("key_length", "2.6.0"),
+    }
     fields_desc = [
         ByteEnumField("key_descriptor_type", 1, {1: "RC4", 2: "RSN"}),
         # Key Information
@@ -458,20 +462,20 @@ class EAPOL_KEY(Packet):
             3: "AES-128-CMAC+AES-128",
         }),
         #
-        LenField("len", None, "H"),
+        LenField("key_length", None, "H"),
         LongField("key_replay_counter", 0),
         XStrFixedLenField("key_nonce", "", 32),
         XStrFixedLenField("key_iv", "", 16),
         XStrFixedLenField("key_rsc", "", 8),
         XStrFixedLenField("key_id", "", 8),
         XStrFixedLenField("key_mic", "", 16),  # XXX size can be 24
-        LenField("key_length", None, "H"),
-        XStrLenField("key", "",
-                     length_from=lambda pkt: pkt.key_length)
+        FieldLenField("key_data_length", None, length_of="key_data"),
+        XStrLenField("key_data", "",
+                     length_from=lambda pkt: pkt.key_data_length)
     ]
 
     def extract_padding(self, s):
-        return s[:self.len], s[self.len:]
+        return s[:self.key_length], s[self.key_length:]
 
     def hashret(self):
         return struct.pack("!B", self.type) + self.payload.hashret()
@@ -482,6 +486,24 @@ def answers(self, other):
             return 1
         return 0
 
+    def guess_key_number(self):
+        """
+        Determines 4-way handshake key number
+
+        :return: key number (1-4), or 0 if it cannot be determined
+        """
+        if self.key_type == 1:
+            if self.key_ack == 1:
+                if self.key_mic == 0:
+                    return 1
+                if self.install == 1:
+                    return 3
+            else:
+                if self.secure == 0:
+                    return 2
+                return 4
+        return 0
+
 
 #############################################################################
 # IEEE 802.1X-2010 - MACsec Key Agreement (MKA) protocol

test/scapy/layers/eap.uts

@@ -65,9 +65,87 @@ assert wifi[EAPOL].key_ack == 1
 assert wifi[EAPOL].key_type == 1
 assert wifi[EAPOL].key_descriptor_type_version == 2
 assert wifi[EAPOL].key_replay_counter == 4
-assert wifi[EAPOL].key_mic == b"\x00" * 16
-assert wifi[EAPOL].key_length == 22
-assert len(wifi[EAPOL].key) == 22
+assert wifi[EAPOL].has_key_mic == 0
+assert wifi[EAPOL].key_data_length == 22
+assert len(wifi[EAPOL].key_data) == 22
+
+= EAPOL-Key - Key 1 - Dissection (1)
+s = b'\x02\x03\x00\x75\x02\x00\x8a\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x12\x6a\xce\x64\xc1\xa6\x44\xd2\x7b\x84\xe0\x39\x26\x3b\x63\x3b\xc3\x74\xe3\x29\x9d\x7d\x45\xe1\xc4\x25\x44\x05\x48\x05\xbf\xe5\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x16\xdd\x14\x00\x0f\xac\x04\x05\xb1\xb6\x8b\x5a\x91\xfc\x04\x06\x83\x84\x06\xe8\xd1\x5f\xdb'
+eapol = EAPOL(s)
+assert(eapol.version == 2)
+assert(eapol.type == 3)
+assert(eapol.len == 117)
+assert(eapol.haslayer(EAPOL_KEY))
+eapol_key = eapol[EAPOL_KEY]
+assert(eapol_key.key_descriptor_type == 2)
+assert(eapol_key.key_descriptor_type_version == 2)
+assert(eapol_key.key_type == 1)
+assert(eapol_key.key_length == 16)
+assert(eapol_key.install == 0)
+assert(eapol_key.key_ack == 1)
+assert(eapol_key.key_mic == b"\x00" * 16)
+assert(eapol_key.secure == 0)
+assert(eapol_key.key_data_length == 22)
+assert(eapol_key.guess_key_number() == 0)
+
+= EAPOL_KEY - Key 2 - Dissection (2)
+s = b'\x02\x03\x00\x75\x02\x01\x0a\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x60\x5e\x85\xa7\x9c\xfa\xfd\xb0\xea\xa0\x50\x68\x3f\x97\xbe\x1b\x66\xde\xf7\xbc\x65\x20\x57\x31\x68\x71\xc2\x73\xc5\xae\x47\x7f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x91\x89\xcd\xf1\x88\x54\x8e\x73\xcd\x37\xd5\x78\x52\x66\x05\x88\x00\x16\x30\x14\x01\x00\x00\x0f\xac\x04\x01\x00\x00\x0f\xac\x04\x01\x00\x00\x0f\xac\x02\x28\x00'
+eapol = EAPOL(s)
+assert(eapol.version == 2)
+assert(eapol.type == 3)
+assert(eapol.len == 117)
+assert(eapol.haslayer(EAPOL_KEY))
+eapol_key = eapol[EAPOL_KEY]
+assert(eapol_key.key_descriptor_type == 2)
+assert(eapol_key.key_descriptor_type_version == 2)
+assert(eapol_key.key_type == 1)
+assert(eapol_key.key_length == 16)
+assert(eapol_key.install == 0)
+assert(eapol_key.key_ack == 0)
+assert(eapol_key.has_key_mic == 1)
+assert(eapol_key.secure == 0)
+assert(eapol_key.key_data_length == 22)
+assert(eapol_key.guess_key_number() == 2)
+
+= EAPOL_KEY - Key 3 - Dissection (3)
+s = b'\x02\x03\x00\x97\x02\x13\xca\x00\x10\x00\x00\x00\x00\x00\x00\x00\x01\x12\x6a\xce\x64\xc1\xa6\x44\xd2\x7b\x84\xe0\x39\x26\x3b\x63\x3b\xc3\x74\xe3\x29\x9d\x7d\x45\xe1\xc4\x25\x44\x05\x48\x05\xbf\xe5\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xce\x1f\x1e\x80\xe7\x6c\xbf\x4a\x5c\xe9\xce\x84\x6d\x20\x7f\x7d\x00\x38\x10\xcc\x53\x66\x65\x5f\x7f\xf5\xd5\x5a\xf8\xc3\x87\x69\x85\xde\x7d\x96\xaa\xfd\x2b\x93\x48\x9f\x6c\xdf\x5f\x9c\x26\x2b\xe1\xad\x21\xeb\xce\x62\xc9\x4d\x88\x97\x1f\xd7\x5e\x23\xf6\x96\xf6\xc0\xe0\x1e\xf3\x52\x85\xe2\xf2\xcc'
+eapol = EAPOL(s)
+assert(eapol.version == 2)
+assert(eapol.type == 3)
+assert(eapol.len == 151)
+assert(eapol.haslayer(EAPOL_KEY))
+eapol_key = eapol[EAPOL_KEY]
+assert(eapol_key.key_descriptor_type == 2)
+assert(eapol_key.key_descriptor_type_version == 2)
+assert(eapol_key.key_type == 1)
+assert(eapol_key.key_length == 16)
+assert(eapol_key.install == 1)
+assert(eapol_key.key_ack == 1)
+assert(eapol_key.has_key_mic == 1)
+assert(eapol_key.secure == 1)
+assert(eapol_key.key_data_length == 56)
+assert(eapol_key.guess_key_number() == 3)
+
+= EAPOL_KEY - Key 4 - Dissection (4)
+s = b'\x02\x03\x00\x5f\x02\x03\x0a\x00\x10\x00\x00\x00\x00\x00\x00\x00\x01\x60\x5e\x85\xa7\x9c\xfa\xfd\xb0\xea\xa0\x50\x68\x3f\x97\xbe\x1b\x66\xde\xf7\xbc\x65\x20\x57\x31\x68\x71\xc2\x73\xc5\xae\x47\x7f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x27\x95\xe1\x76\xeb\x6b\xba\xc1\x6e\x06\x16\xb4\x14\x94\xd6\x0a\x00\x00'
+eapol = EAPOL(s)
+assert(eapol.version == 2)
+assert(eapol.type == 3)
+assert(eapol.len == 95)
+assert(eapol.haslayer(EAPOL_KEY))
+eapol_key = eapol[EAPOL_KEY]
+assert(eapol_key.key_descriptor_type == 2)
+assert(eapol_key.key_descriptor_type_version == 2)
+assert(eapol_key.key_type == 1)
+assert(eapol_key.key_length == 16)
+assert(eapol_key.install == 0)
+assert(eapol_key.key_ack == 0)
+assert(eapol_key.has_key_mic == 1)
+assert(eapol_key.secure == 1)
+assert(eapol_key.key_data_length == 0)
+assert(eapol_key.key_data == b'')
+assert(eapol_key.guess_key_number() == 4)
+
 
 ############
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