shell bypass 403
# CER decoder
from pyasn1.type import univ
from pyasn1.codec.ber import decoder
from pyasn1.compat.octets import oct2int
from pyasn1 import error
class BooleanDecoder(decoder.AbstractSimpleDecoder):
protoComponent = univ.Boolean(0)
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head or length != 1:
raise error.PyAsn1Error('Not single-octet Boolean payload')
byte = oct2int(head[0])
# CER/DER specifies encoding of TRUE as 0xFF and FALSE as 0x0, while
# BER allows any non-zero value as TRUE; cf. sections 8.2.2. and 11.1
# in http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
if byte == 0xff:
value = 1
elif byte == 0x00:
value = 0
else:
raise error.PyAsn1Error('Unexpected Boolean payload: %s' % byte)
return self._createComponent(asn1Spec, tagSet, value), tail
tagMap = decoder.tagMap.copy()
tagMap.update({
univ.Boolean.tagSet: BooleanDecoder()
})
typeMap = decoder.typeMap
class Decoder(decoder.Decoder): pass
decode = Decoder(tagMap, decoder.typeMap)