Infinite recurision in ans1/ber decoding #1639
Description
Brief description
Decoding some invalid ans/ber input results in infinite recursion instead of appropriate exception
Environment
- Scapy version: 6d41839
- Python version: 2.7.15rc1
- Operating System: Ubuntu 18.04.1 LTS
How to reproduce
SNMP('0a\x02\x01\x00\x04\x06public\xa3T\x02\x02D\xd0\x02\x01\x00\x02\x01\x000H0F\x06\x08+\x06\x01\x02\x01\x01\x05\x00\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D\x00\x03\x01\x02D')(This is test case 00017616 from the req-enc segment of the PROTOS SNMPv1 test suite https://www.ee.oulu.fi/roles/ouspg/PROTOS_Test-Suite_c06-snmpv1 ) There are other cases in that suite that trigger what appears to be the same bug.
Actual result
Traceback (most recent call last):
File "", line 1, in
File "scapy/base_classes.py", line 252, in call
i.init(*args, **kargs)
File "scapy/packet.py", line 138, in init
self.dissect(_pkt)
File "scapy/packet.py", line 806, in dissect
s = self.do_dissect(s)
File "scapy/asn1packet.py", line 33, in do_dissect
return self.ASN1_root.dissect(self, x)
File "scapy/asn1fields.py", line 378, in dissect
_, x = self.m2i(pkt, s)
File "scapy/asn1fields.py", line 370, in m2i
s = obj.dissect(pkt, s)
File "scapy/asn1fields.py", line 138, in dissect
v, s = self.m2i(pkt, s)
File "scapy/asn1fields.py", line 549, in m2i
return self.extract_packet(choice, s)
File "scapy/asn1fields.py", line 122, in extract_packet
c = cls(s)
File "scapy/base_classes.py", line 252, in call
i.init(*args, **kargs)
File "scapy/packet.py", line 138, in init
self.dissect(_pkt)
File "scapy/packet.py", line 806, in dissect
s = self.do_dissect(s)
File "scapy/asn1packet.py", line 33, in do_dissect
return self.ASN1_root.dissect(self, x)
File "scapy/asn1fields.py", line 378, in dissect
_, x = self.m2i(pkt, s)
File "scapy/asn1fields.py", line 370, in m2i
s = obj.dissect(pkt, s)
File "scapy/asn1fields.py", line 138, in dissect
v, s = self.m2i(pkt, s)
File "scapy/asn1fields.py", line 419, in m2i
c, s = self.extract_packet(self.cls, s)
File "scapy/asn1fields.py", line 122, in extract_packet
c = cls(s)
File "scapy/base_classes.py", line 252, in call
i.init(*args, **kargs)
File "scapy/packet.py", line 138, in init
self.dissect(_pkt)
File "scapy/packet.py", line 806, in dissect
s = self.do_dissect(s)
File "scapy/asn1packet.py", line 33, in do_dissect
return self.ASN1_root.dissect(self, x)
File "scapy/asn1fields.py", line 378, in dissect
_, x = self.m2i(pkt, s)
File "scapy/asn1fields.py", line 370, in m2i
s = obj.dissect(pkt, s)
File "scapy/asn1fields.py", line 138, in dissect
v, s = self.m2i(pkt, s)
File "scapy/asn1fields.py", line 101, in m2i
return codec.dec(s, context=self.context)
File "scapy/asn1/ber.py", line 266, in dec
return cls.do_dec(s, context, safe)
File "scapy/asn1/ber.py", line 261, in do_dec
return codec.dec(s, context, safe)
...
File "scapy/asn1/ber.py", line 261, in do_dec
return codec.dec(s, context, safe)
File "scapy/asn1/ber.py", line 266, in dec
return cls.do_dec(s, context, safe)
File "scapy/asn1/ber.py", line 261, in do_dec
return codec.dec(s, context, safe)
File "scapy/asn1/ber.py", line 266, in dec
return cls.do_dec(s, context, safe)
File "scapy/asn1/ber.py", line 255, in do_dec
if p not in context:
File "scapy/utils.py", line 734, in contains
return val in self.rdict
File "scapy/utils.py", line 711, in eq
return self._value == int(other)
RuntimeError: maximum recursion depth exceeded while calling a Python object
Expected result
Domain specific exception