BER encoding error on Python 3

[cq674350529]

Brief description

When making up SNMP packets using scapy and call packet.build(), an ValueError occurred.

In [1]: from scapy.all import *                                                                                           

In [2]: snmp_set_packet = SNMP(version=0, community='public', PDU=SNMPset(varbindlist=[SNMPvarbind(oid=ASN1_OID("1.3.6.1.2
   ...: .1.1.4.0"), value=RandBin())]))                                                                                   

In [3]: snmp_set_packet.build() 

# ... something omitted

/usr/local/lib/python3.5/dist-packages/scapy/asn1/ber.py in enc(cls, s)
    295     @classmethod
    296     def enc(cls, s):
    297         if isinstance(s, six.string_types):
    298             return BERcodec_STRING.enc(s)
    299         else:
--> 300             return BERcodec_INTEGER.enc(int(s))
    301 
    302 

ValueError: invalid literal for int() with base 10: b'(U\x1f\xe1t\xe7\xc0\xec\x8f9\x96<\xce~\r\xe8\x8eh\xb5\x1atq\x10}Q\x8a\x9d\x96\\\xeeq\xe7\xfb*\x8b\x98\xa1]\x06\xc1\x93\x9d\x06\x1d\x87\x83)\x88\xd8\x9eOxj\x19\xdd\xce\xd5\xa1\x03my\x81\xe9\xfa\x07\x

the string_types in six module is as follows. In py3 env, the type of data is bytes instead of str. So maybe use if isinstance(s, six.binary_type) instead, or add another condition?

if PY3:
    string_types = str,
    integer_types = int,
    class_types = type,
    text_type = str
    binary_type = bytes

    MAXSIZE = sys.maxsize
else:
    string_types = basestring,
    integer_types = (int, long)
    class_types = (type, types.ClassType)
    text_type = unicode
    binary_type = str

Environment

• Scapy version: 2.4.2
• Python version: 3.5
• Operating System: Ubuntu 16.04

[gpotter2]

Thanks for the report & sorry for the delay,
Could you check that #1930 fixes it ? Thanks !

[cq674350529]

Yes, it works.
Originally, I use if isinstance(s, six.binary_type) to fix it temporarily in my machine, which is same to the condition if isinstance(s, (str, bytes)) in #1930. Also, I have tested it with condition if isinstance(s, six.string_types + (bytes,)), it works too.