def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
if not head:
raise error.PyAsn1Error('Empty substrate')
trailingBits = oct2int(head[0])
if trailingBits > 7:
raise error.PyAsn1Error('Trailing bits overflow %s' %
trailingBits)
head = head[1:]
lsb = p = 0
l = len(head) - 1
b = []
while p <= l:
if p == l:
lsb = trailingBits
j = 7
o = oct2int(head[p])
while j >= lsb:
b.append((o >> j) & 0x01)
j -= 1
p += 1
return self._createComponent(asn1Spec, tagSet, b), tail
r = self._createComponent(asn1Spec, tagSet, ())
if substrateFun:
return substrateFun(r, substrate, length)
while head:
component, head = decodeFun(head, self.protoComponent)
r = r + component
return r, tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if not substrate:
raise error.PyAsn1Error('Empty substrate')
oid = (); index = 0
# Get the first subid
subId = oct2int(substrate[index])
oid = oid + divmod(subId, 40)
index = index + 1
substrateLen = len(substrate)
while index < substrateLen:
subId = oct2int(substrate[index])
if subId < 128:
oid = oid + (subId,)
index = index + 1
else:
# Construct subid from a number of octets
nextSubId = subId
subId = 0
while nextSubId >= 128 and index < substrateLen:
subId = (subId << 7) + (nextSubId & 0x7F)
index = index + 1
nextSubId = oct2int(substrate[index])
if index == substrateLen:
raise error.SubstrateUnderrunError(
'Short substrate for OID %s' % oid
)
subId = (subId << 7) + nextSubId
oid = oid + (subId,)
index = index + 1
return self._createComponent(asn1Spec, tagSet, oid), substrate[index:]
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
if not head:
raise error.PyAsn1Error('Empty substrate')
trailingBits = oct2int(head[0])
if trailingBits > 7:
raise error.PyAsn1Error(
'Trailing bits overflow %s' % trailingBits
)
head = head[1:]
lsb = p = 0; l = len(head)-1; b = []
while p <= l:
if p == l:
lsb = trailingBits
j = 7
o = oct2int(head[p])
while j >= lsb:
b.append((o>>j)&0x01)
j -= 1
p += 1
return self._createComponent(asn1Spec, tagSet, b), tail
r = self._createComponent(asn1Spec, tagSet, ())
if substrateFun:
return substrateFun(r, substrate, length)
while head:
component, head = decodeFun(head, self.protoComponent)
r = r + component
return r, tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
return self._createComponent(asn1Spec, tagSet, 0.0), tail
fo = oct2int(head[0])
head = head[1:]
if fo & 0x80: # binary encoding
if not head:
raise error.PyAsn1Error("Incomplete floating-point value")
n = (fo & 0x03) + 1
if n == 4:
n = oct2int(head[0])
head = head[1:]
eo, head = head[:n], head[n:]
if not eo or not head:
raise error.PyAsn1Error('Real exponent screwed')
e = oct2int(eo[0]) & 0x80 and -1 or 0
while eo: # exponent
e <<= 8
e |= oct2int(eo[0])
eo = eo[1:]
b = fo >> 4 & 0x03 # base bits
if b > 2:
raise error.PyAsn1Error('Illegal Real base')
if b == 1: # encbase = 8
e *= 3
elif b == 2: # encbase = 16
e *= 4
p = 0
while head: # value
p <<= 8
p |= oct2int(head[0])
head = head[1:]
if fo & 0x40: # sign bit
p = -p
sf = fo >> 2 & 0x03 # scale bits
p *= 2**sf
value = (p, 2, e)
elif fo & 0x40: # infinite value
value = fo & 0x01 and '-inf' or 'inf'
elif fo & 0xc0 == 0: # character encoding
if not head:
raise error.PyAsn1Error("Incomplete floating-point value")
try:
if fo & 0x3 == 0x1: # NR1
value = (int(head), 10, 0)
elif fo & 0x3 == 0x2: # NR2
value = float(head)
elif fo & 0x3 == 0x3: # NR3
value = float(head)
else:
raise error.SubstrateUnderrunError('Unknown NR (tag %s)' %
fo)
except ValueError:
raise error.SubstrateUnderrunError('Bad character Real syntax')
else:
raise error.SubstrateUnderrunError('Unknown encoding (tag %s)' %
fo)
return self._createComponent(asn1Spec, tagSet, value), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if not substrate:
raise error.PyAsn1Error('Empty substrate')
oid = (); index = 0
# Get the first subid
subId = oct2int(substrate[index])
oid = oid + divmod(subId, 40)
index = index + 1
substrateLen = len(substrate)
while index < substrateLen:
subId = oct2int(substrate[index])
if subId < 128:
oid = oid + (subId,)
index = index + 1
else:
# Construct subid from a number of octets
nextSubId = subId
subId = 0
while nextSubId >= 128 and index < substrateLen:
subId = (subId << 7) + (nextSubId & 0x7F)
index = index + 1
nextSubId = oct2int(substrate[index])
if index == substrateLen:
raise error.SubstrateUnderrunError(
'Short substrate for OID %s' % oid
)
subId = (subId << 7) + nextSubId
oid = oid + (subId,)
index = index + 1
return self._createComponent(asn1Spec, tagSet, oid), substrate[index:]
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
if not substrate:
raise error.PyAsn1Error('Missing initial octet')
trailingBits = oct2int(substrate[0])
if trailingBits > 7:
raise error.PyAsn1Error(
'Trailing bits overflow %s' % trailingBits
)
substrate = substrate[1:]
lsb = p = 0; l = len(substrate)-1; b = ()
while p <= l:
if p == l:
lsb = trailingBits
j = 7
o = oct2int(substrate[p])
while j >= lsb:
b = b + ((o>>j)&0x01,)
j = j - 1
p = p + 1
return self._createComponent(asn1Spec, tagSet, b), ''
r = self._createComponent(asn1Spec, tagSet, ())
if not decodeFun:
return r, substrate
while substrate:
component, substrate = decodeFun(substrate)
r = r + component
return r, substrate
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
raise error.PyAsn1Error('Empty substrate')
# Get the first subid
subId = oct2int(head[0])
oid = divmod(subId, 40)
index = 1
substrateLen = len(head)
while index < substrateLen:
subId = oct2int(head[index])
index = index + 1
if subId == 128:
# ASN.1 spec forbids leading zeros (0x80) in sub-ID OID
# encoding, tolerating it opens a vulnerability.
# See http://www.cosic.esat.kuleuven.be/publications/article-1432.pdf page 7
raise error.PyAsn1Error('Invalid leading 0x80 in sub-OID')
elif subId > 128:
# Construct subid from a number of octets
nextSubId = subId
subId = 0
while nextSubId >= 128:
subId = (subId << 7) + (nextSubId & 0x7F)
if index >= substrateLen:
raise error.SubstrateUnderrunError(
'Short substrate for sub-OID past %s' % (oid,)
)
nextSubId = oct2int(head[index])
index = index + 1
subId = (subId << 7) + nextSubId
oid = oid + (subId,)
return self._createComponent(asn1Spec, tagSet, oid), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
if not substrate:
raise error.PyAsn1Error('Missing initial octet')
trailingBits = oct2int(substrate[0])
if trailingBits > 7:
raise error.PyAsn1Error(
'Trailing bits overflow %s' % trailingBits
)
substrate = substrate[1:]
lsb = p = 0; l = len(substrate)-1; b = ()
while p <= l:
if p == l:
lsb = trailingBits
j = 7
o = oct2int(substrate[p])
while j >= lsb:
b = b + ((o>>j)&0x01,)
j = j - 1
p = p + 1
return self._createComponent(asn1Spec, tagSet, b), ''
r = self._createComponent(asn1Spec, tagSet, ())
if not decodeFun:
return r, substrate
while substrate:
component, substrate = decodeFun(substrate)
r = r + component
return r, substrate
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
raise error.PyAsn1Error('Empty substrate')
# Get the first subid
subId = oct2int(head[0])
oid = divmod(subId, 40)
index = 1
substrateLen = len(head)
while index < substrateLen:
subId = oct2int(head[index])
index = index + 1
if subId == 128:
# ASN.1 spec forbids leading zeros (0x80) in sub-ID OID
# encoding, tolerating it opens a vulnerability.
# See http://www.cosic.esat.kuleuven.be/publications/article-1432.pdf page 7
raise error.PyAsn1Error('Invalid leading 0x80 in sub-OID')
elif subId > 128:
# Construct subid from a number of octets
nextSubId = subId
subId = 0
while nextSubId >= 128:
subId = (subId << 7) + (nextSubId & 0x7F)
if index >= substrateLen:
raise error.SubstrateUnderrunError(
'Short substrate for sub-OID past %s' % (oid,)
)
nextSubId = oct2int(head[index])
index = index + 1
subId = (subId << 7) + nextSubId
oid = oid + (subId,)
return self._createComponent(asn1Spec, tagSet, oid), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
length, state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
return self._createComponent(asn1Spec, tagSet, 0.0), tail
fo = oct2int(head[0]); head = head[1:]
if fo & 0x80: # binary enoding
n = (fo & 0x03) + 1
if n == 4:
n = oct2int(head[0])
head = head[1:]
eo, head = head[:n], head[n:]
if not eo or not head:
raise error.PyAsn1Error('Real exponent screwed')
e = oct2int(eo[0]) & 0x80 and -1 or 0
while eo: # exponent
e <<= 8
e |= oct2int(eo[0])
eo = eo[1:]
b = fo >> 4 & 0x03 # base bits
if b > 2:
raise error.PyAsn1Error('Illegal Real base')
if b == 1: # encbase = 8
e *= 3
elif b == 2: # encbase = 16
e *= 4
p = 0
while head: # value
p <<= 8
p |= oct2int(head[0])
head = head[1:]
if fo & 0x40: # sign bit
p = -p
sf = fo >> 2 & 0x03 # scale bits
p *= 2**sf
value = (p, 2, e)
elif fo & 0x40: # infinite value
value = fo & 0x01 and '-inf' or 'inf'
elif fo & 0xc0 == 0: # character encoding
try:
if fo & 0x3 == 0x1: # NR1
value = (int(head), 10, 0)
elif fo & 0x3 == 0x2: # NR2
value = Decimal(head)
elif fo & 0x3 == 0x3: # NR3
value = Decimal(head)
else:
raise error.SubstrateUnderrunError(
'Unknown NR (tag %s)' % fo
)
except ValueError:
raise error.SubstrateUnderrunError(
'Bad character Real syntax'
)
else:
raise error.SubstrateUnderrunError(
'Unknown encoding (tag %s)' % fo
)
return self._createComponent(asn1Spec, tagSet, value), tail
def __asSocketAddress(self):
if not hasattr(self, '__tuple_value'):
v = self.asOctets()
self.__tuple_value = (
inet_ntop(socket.AF_INET, v[:4]),
oct2int(v[4]) << 8 | oct2int(v[5]),
)
return self.__tuple_value
def __asSocketAddress(self):
if not hasattr(self, '__tuple_value'):
v = self.asOctets()
self.__tuple_value = (
inet_ntop(AF_INET, v[:4]),
oct2int(v[4]) << 8 | oct2int(v[5])
)
return self.__tuple_value
def __getitem__(self, i):
if not hasattr(self, '__tuple_value'):
v = self.asOctets()
self.__tuple_value = (
inet_ntop(AF_INET, v[:4]),
oct2int(v[4]) << 8 | oct2int(v[5])
)
return self.__tuple_value[i]
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
length, state, decodeFun):
substrate = substrate[:length]
if not length:
raise error.SubstrateUnderrunError('Short substrate for Real')
fo = oct2int(substrate[0]); substrate = substrate[1:]
if fo & 0x40: # infinite value
value = fo & 0x01 and '-inf' or 'inf'
elif fo & 0x80: # binary enoding
if fo & 0x11 == 0:
n = 1
elif fo & 0x01:
n = 2
elif fo & 0x02:
n = 3
else:
n = oct2int(substrate[0])
eo, substrate = substrate[:n], substrate[n:]
if not eo or not substrate:
raise error.PyAsn1Error('Real exponent screwed')
e = 0
while eo: # exponent
e <<= 8
e |= oct2int(eo[0])
eo = eo[1:]
p = 0
while substrate: # value
p <<= 8
p |= oct2int(substrate[0])
substrate = substrate[1:]
if fo & 0x40: # sign bit
p = -p
value = (p, 2, e)
elif fo & 0xc0 == 0: # character encoding
try:
if fo & 0x3 == 0x1: # NR1
value = (int(substrate), 10, 0)
elif fo & 0x3 == 0x2: # NR2
value = float(substrate)
elif fo & 0x3 == 0x3: # NR3
value = float(substrate)
else:
raise error.SubstrateUnderrunError(
'Unknown NR (tag %s)' % fo
)
except ValueError:
raise error.SubstrateUnderrunError(
'Bad character Real syntax'
)
elif fo & 0xc0 == 0x40: # special real value
pass
else:
raise error.SubstrateUnderrunError(
'Unknown encoding (tag %s)' % fo
)
return self._createComponent(asn1Spec, tagSet, value), substrate
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
length, state, decodeFun):
substrate = substrate[:length]
if not length:
raise error.SubstrateUnderrunError('Short substrate for Real')
fo = oct2int(substrate[0]); substrate = substrate[1:]
if fo & 0x40: # infinite value
value = fo & 0x01 and '-inf' or 'inf'
elif fo & 0x80: # binary enoding
if fo & 0x11 == 0:
n = 1
elif fo & 0x01:
n = 2
elif fo & 0x02:
n = 3
else:
n = oct2int(substrate[0])
eo, substrate = substrate[:n], substrate[n:]
if not eo or not substrate:
raise error.PyAsn1Error('Real exponent screwed')
e = 0
while eo: # exponent
e <<= 8
e |= oct2int(eo[0])
eo = eo[1:]
p = 0
while substrate: # value
p <<= 8
p |= oct2int(substrate[0])
substrate = substrate[1:]
if fo & 0x40: # sign bit
p = -p
value = (p, 2, e)
elif fo & 0xc0 == 0: # character encoding
try:
if fo & 0x3 == 0x1: # NR1
value = (int(substrate), 10, 0)
elif fo & 0x3 == 0x2: # NR2
value = float(substrate)
elif fo & 0x3 == 0x3: # NR3
value = float(substrate)
else:
raise error.SubstrateUnderrunError(
'Unknown NR (tag %s)' % fo
)
except ValueError:
raise error.SubstrateUnderrunError(
'Bad character Real syntax'
)
elif fo & 0xc0 == 0x40: # special real value
pass
else:
raise error.SubstrateUnderrunError(
'Unknown encoding (tag %s)' % fo
)
return self._createComponent(asn1Spec, tagSet, value), substrate
def __getitem__(self, i):
if not hasattr(self, '__tuple_value'):
if not has_ipv6:
raise error.PySnmpError('IPv6 not supported by platform')
v = self.asOctets()
self.__tuple_value = (
inet_ntop(socket.AF_INET6, v[:16]),
oct2int(v[16]) << 8 | oct2int(v[17]),
0, # flowinfo
0) # scopeid
return self.__tuple_value[i]
def __getitem__(self, i):
if not hasattr(self, '__tuple_value'):
if AF_INET6 is None:
raise error.PySnmpError('IPv6 not supported by platform')
v = self.asOctets()
self.__tuple_value = (
inet_ntop(AF_INET6, v[:16]),
oct2int(v[16]) << 8 | oct2int(v[17]),
0,
0)
return self.__tuple_value[i]
def __asSocketAddress(self):
if not hasattr(self, '__tuple_value'):
if not has_ipv6:
raise error.PySnmpError('IPv6 not supported by platform')
v = self.asOctets()
self.__tuple_value = (
inet_ntop(socket.AF_INET6, v[:16]),
oct2int(v[16]) << 8 | oct2int(v[17]),
0, # flowinfo
0) # scopeid
return self.__tuple_value
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
length, state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
raise error.SubstrateUnderrunError('Short substrate for Real')
fo = oct2int(head[0]); head = head[1:]
if fo & 0x40: # infinite value
value = fo & 0x01 and '-inf' or 'inf'
elif fo & 0x80: # binary enoding
n = (fo & 0x03) + 1
if n == 4:
n = oct2int(head[0])
eo, head = head[:n], head[n:]
if not eo or not head:
raise error.PyAsn1Error('Real exponent screwed')
e = oct2int(eo[0]) & 0x80 and -1 or 0
while eo: # exponent
e <<= 8
e |= oct2int(eo[0])
eo = eo[1:]
p = 0
while head: # value
p <<= 8
p |= oct2int(head[0])
head = head[1:]
if fo & 0x40: # sign bit
p = -p
value = (p, 2, e)
elif fo & 0xc0 == 0: # character encoding
try:
if fo & 0x3 == 0x1: # NR1
value = (int(head), 10, 0)
elif fo & 0x3 == 0x2: # NR2
value = float(head)
elif fo & 0x3 == 0x3: # NR3
value = float(head)
else:
raise error.SubstrateUnderrunError(
'Unknown NR (tag %s)' % fo
)
except ValueError:
raise error.SubstrateUnderrunError(
'Bad character Real syntax'
)
elif fo & 0xc0 == 0x40: # special real value
pass
else:
raise error.SubstrateUnderrunError(
'Unknown encoding (tag %s)' % fo
)
return self._createComponent(asn1Spec, tagSet, value), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
length, state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
return self._createComponent(asn1Spec, tagSet, 0.0), tail
fo = oct2int(head[0]); head = head[1:]
if fo & 0x80: # binary enoding
n = (fo & 0x03) + 1
if n == 4:
n = oct2int(head[0])
eo, head = head[:n], head[n:]
if not eo or not head:
raise error.PyAsn1Error('Real exponent screwed')
e = oct2int(eo[0]) & 0x80 and -1 or 0
while eo: # exponent
e <<= 8
e |= oct2int(eo[0])
eo = eo[1:]
p = 0
while head: # value
p <<= 8
p |= oct2int(head[0])
head = head[1:]
if fo & 0x40: # sign bit
p = -p
value = (p, 2, e)
elif fo & 0x40: # infinite value
value = fo & 0x01 and '-inf' or 'inf'
elif fo & 0xc0 == 0: # character encoding
try:
if fo & 0x3 == 0x1: # NR1
value = (int(head), 10, 0)
elif fo & 0x3 == 0x2: # NR2
value = float(head)
elif fo & 0x3 == 0x3: # NR3
value = float(head)
else:
raise error.SubstrateUnderrunError(
'Unknown NR (tag %s)' % fo
)
except ValueError:
raise error.SubstrateUnderrunError(
'Bad character Real syntax'
)
else:
raise error.SubstrateUnderrunError(
'Unknown encoding (tag %s)' % fo
)
return self._createComponent(asn1Spec, tagSet, value), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
if not head:
raise error.PyAsn1Error('Empty substrate')
trailingBits = oct2int(head[0])
if trailingBits > 7:
raise error.PyAsn1Error('Trailing bits overflow %s' %
trailingBits)
head = head[1:]
value = self.protoComponent.fromOctetString(head, trailingBits)
return self._createComponent(asn1Spec, tagSet, value), tail
if not self.supportConstructedForm:
raise error.PyAsn1Error(
'Constructed encoding form prohibited at %s' %
self.__class__.__name__)
bitString = self._createComponent(asn1Spec, tagSet)
if substrateFun:
return substrateFun(bitString, substrate, length)
while head:
component, head = decodeFun(head, self.protoComponent)
bitString += component
return bitString, tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if not substrate:
raise error.PyAsn1Error('Empty substrate')
if substrate in self.precomputedValues:
value = self.precomputedValues[substrate]
else:
firstOctet = oct2int(substrate[0])
if firstOctet & 0x80:
value = -1
else:
value = 0
for octet in substrate:
value = value << 8 | oct2int(octet)
return self._createComponent(asn1Spec, tagSet, value), substrate
def from_bytes(octets, signed=False):
value = long(b2a_hex(str(octets)), 16)
if signed and oct2int(octets[0]) & 0x80:
return value - (1 << len(octets) * 8)
return value
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if not substrate:
raise error.PyAsn1Error('Empty substrate')
if substrate in self.precomputedValues:
value = self.precomputedValues[substrate]
else:
firstOctet = oct2int(substrate[0])
if firstOctet & 0x80:
value = -1
else:
value = 0
for octet in substrate:
value = value << 8 | oct2int(octet)
return self._createComponent(asn1Spec, tagSet, value), substrate
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
return self._createComponent(asn1Spec, tagSet, 0), tail
if head in self.precomputedValues:
value = self.precomputedValues[head]
else:
firstOctet = oct2int(head[0])
if firstOctet & 0x80:
value = -1
else:
value = 0
for octet in head:
value = value << 8 | oct2int(octet)
return self._createComponent(asn1Spec, tagSet, value), tail
def from_bytes(octets, signed=False):
value = long(b2a_hex(str(octets)), 16)
if signed and oct2int(octets[0]) & 0x80:
return value - (1 << len(octets) * 8)
return value
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if tagSet[0].tagFormat == tag.tagFormatSimple: # XXX what tag to check?
if not head:
raise error.PyAsn1Error('Empty substrate')
trailingBits = oct2int(head[0])
if trailingBits > 7:
raise error.PyAsn1Error(
'Trailing bits overflow %s' % trailingBits
)
head = head[1:]
value = self.protoComponent.fromOctetString(head, trailingBits)
return self._createComponent(asn1Spec, tagSet, value), tail
if not self.supportConstructedForm:
raise error.PyAsn1Error('Constructed encoding form prohibited at %s' % self.__class__.__name__)
bitString = self._createComponent(asn1Spec, tagSet)
if substrateFun:
return substrateFun(bitString, substrate, length)
while head:
component, head = decodeFun(head, self.protoComponent)
bitString += component
return bitString, tail
def valueDecoder(self,
substrate,
asn1Spec,
tagSet=None,
length=None,
state=None,
decodeFun=None,
substrateFun=None,
**options):
if length != 1:
raise error.PyAsn1Error('Not single-octet Boolean payload')
for chunk in readFromStream(substrate, length, options):
if isinstance(chunk, SubstrateUnderrunError):
yield chunk
byte = oct2int(chunk[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 https://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)
yield self._createComponent(asn1Spec, tagSet, value, **options)
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
return self._createComponent(asn1Spec, tagSet, 0), tail
if head in self.precomputedValues:
value = self.precomputedValues[head]
else:
firstOctet = oct2int(head[0])
if firstOctet & 0x80:
value = -1
else:
value = 0
for octet in head:
value = value << 8 | oct2int(octet)
return self._createComponent(asn1Spec, tagSet, value), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
raise error.PyAsn1Error('Empty substrate')
oid = ()
index = 0
substrateLen = len(head)
while index < substrateLen:
subId = oct2int(head[index])
index += 1
if subId < 128:
oid = oid + (subId,)
elif subId > 128:
# Construct subid from a number of octets
nextSubId = subId
subId = 0
while nextSubId >= 128:
subId = (subId << 7) + (nextSubId & 0x7F)
if index >= substrateLen:
raise error.SubstrateUnderrunError(
'Short substrate for sub-OID past %s' % (oid,)
)
nextSubId = oct2int(head[index])
index += 1
oid = oid + ((subId << 7) + nextSubId,)
elif subId == 128:
# ASN.1 spec forbids leading zeros (0x80) in OID
# encoding, tolerating it opens a vulnerability. See
# http://www.cosic.esat.kuleuven.be/publications/article-1432.pdf
# page 7
raise error.PyAsn1Error('Invalid octet 0x80 in OID encoding')
# Decode two leading arcs
if 0 <= oid[0] <= 39:
oid = (0,) + oid
elif 40 <= oid[0] <= 79:
oid = (1, oid[0]-40) + oid[1:]
elif oid[0] >= 80:
oid = (2, oid[0]-80) + oid[1:]
else:
raise error.PyAsn1Error('Malformed first OID octet: %s' % head[0])
return self._createComponent(asn1Spec, tagSet, oid), tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if not head:
raise error.PyAsn1Error('Empty substrate')
oid = ()
index = 0
substrateLen = len(head)
while index < substrateLen:
subId = oct2int(head[index])
index += 1
if subId < 128:
oid = oid + (subId,)
elif subId > 128:
# Construct subid from a number of octets
nextSubId = subId
subId = 0
while nextSubId >= 128:
subId = (subId << 7) + (nextSubId & 0x7F)
if index >= substrateLen:
raise error.SubstrateUnderrunError(
'Short substrate for sub-OID past %s' % (oid,)
)
nextSubId = oct2int(head[index])
index += 1
oid = oid + ((subId << 7) + nextSubId,)
elif subId == 128:
# ASN.1 spec forbids leading zeros (0x80) in OID
# encoding, tolerating it opens a vulnerability. See
# http://www.cosic.esat.kuleuven.be/publications/article-1432.pdf
# page 7
raise error.PyAsn1Error('Invalid octet 0x80 in OID encoding')
# Decode two leading arcs
if 0 <= oid[0] <= 39:
oid = (0,) + oid
elif 40 <= oid[0] <= 79:
oid = (1, oid[0] - 40) + oid[1:]
elif oid[0] >= 80:
oid = (2, oid[0] - 80) + oid[1:]
else:
raise error.PyAsn1Error('Malformed first OID octet: %s' % head[0])
return self._createComponent(asn1Spec, tagSet, oid), tail
def from_bytes(octets, signed=False):
if not octets:
return 0
value = long(b2a_hex(ensureString(octets)), 16)
if signed and oct2int(octets[0]) & 0x80:
return value - (1 << len(octets) * 8)
return value
def from_bytes(octets, signed=False):
if not octets:
return 0
value = long(b2a_hex(ensureString(octets)), 16)
if signed and oct2int(octets[0]) & 0x80:
return value - (1 << len(octets) * 8)
return value
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if not substrate:
raise error.PyAsn1Error('Empty substrate')
byte = oct2int(substrate[0])
if byte == 0xff:
value = 1
elif byte == 0x00:
value = 0
else:
raise error.PyAsn1Error('Boolean CER violation: %s' % byte)
return self._createComponent(asn1Spec, tagSet, value), substrate[1:]
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun, substrateFun):
head, tail = substrate[:length], substrate[length:]
if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
if not head:
raise error.PyAsn1Error('Empty substrate')
trailingBits = oct2int(head[0])
if trailingBits > 7:
raise error.PyAsn1Error(
'Trailing bits overflow %s' % trailingBits
)
head = head[1:]
if BITPATTERN:
# Use faster method with lookup table
p = 0; l = len(head)-1; b = []
while p < l:
b.extend(BITPATTERN[oct2int(head[p])])
p += 1
b.extend(BITPATTERN[oct2int(head[p])][0:8-trailingBits])
else:
# Use original, slower method
lsb = p = 0; l = len(head)-1; b = ()
while p <= l:
if p == l:
lsb = trailingBits
j = 7
o = oct2int(head[p])
while j >= lsb:
b = b + ((o>>j)&0x01,)
j = j - 1
p = p + 1
return self._createComponent(asn1Spec, tagSet, b), tail
r = self._createComponent(asn1Spec, tagSet, ())
if substrateFun:
return substrateFun(r, substrate, length)
while head:
component, head = decodeFun(head)
r = r + component
return r, tail
def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
state, decodeFun):
substrate = substrate[:length]
if not substrate:
raise error.PyAsn1Error('Empty substrate')
byte = oct2int(substrate[0])
if byte == 0xff:
value = 1
elif byte == 0x00:
value = 0
else:
raise error.PyAsn1Error('Boolean CER violation: %s' % byte)
return self._createComponent(asn1Spec, tagSet, value), substrate[1:]
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
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
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
if value.isPlusInfinity():
return int2oct(0x40), 0
if value.isMinusInfinity():
return int2oct(0x41), 0
m, b, e = value
if not m:
return null, 0
if b == 10:
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), 0
elif b == 2:
fo = 0x80 # binary enoding
if m < 0:
fo = fo | 0x40 # sign bit
m = -m
while int(m) != m: # drop floating point
m *= 2
e -= 1
while m & 0x1 == 0: # mantissa normalization
m >>= 1
e += 1
eo = null
while e not in (0, -1):
eo = int2oct(e & 0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n // 0xff + 1) + eo
po = null
while m:
po = int2oct(m & 0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, 0
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
if value.isPlusInfinity():
return int2oct(0x40), 0
if value.isMinusInfinity():
return int2oct(0x41), 0
m, b, e = value
if not m:
return null, 0
if b == 10:
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), 0
elif b == 2:
fo = 0x80 # binary enoding
if m < 0:
fo = fo | 0x40 # sign bit
m = -m
while int(m) != m: # drop floating point
m *= 2
e -= 1
while m & 0x1 == 0: # mantissa normalization
m >>= 1
e += 1
eo = null
while e not in (0, -1):
eo = int2oct(e&0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n//0xff+1) + eo
po = null
while m:
po = int2oct(m&0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, 0
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
def prettyOut(self, value): # override asn1 type method
"""Implements DISPLAY-HINT evaluation"""
if self.displayHint and (self.__integer.isSuperTypeOf(self)
or self.__unsigned32.isSuperTypeOf(self)
or self.__timeticks.isSuperTypeOf(self)
or self.__counter32.isSuperTypeOf(self)
or self.__counter64.isSuperTypeOf(self)):
_ = lambda t, f=0: (t, f)
t, f = _(*self.displayHint.split('-'))
if t == 'x':
return '0x%x' % value
elif t == 'd':
try:
return '%.*f' % (int(f), float(value) / pow(10, int(f)))
except Exception:
raise SmiError('float num evaluation error: %s' %
sys.exc_info()[1])
elif t == 'o':
return '0%o' % value
elif t == 'b':
v = value
r = ['B']
while v:
r.insert(0, '%d' % (v & 0x01))
v >>= 1
return ''.join(r)
else:
raise SmiError('Unsupported numeric type spec: %s' % t)
elif self.displayHint and self.__octetString.isSuperTypeOf(self):
r = ''
v = self.__class__(value).asOctets()
d = self.displayHint
while v and d:
# 1
if d[0] == '*':
repeatIndicator = repeatCount = octets.oct2int(v[0])
d = d[1:]
v = v[1:]
else:
repeatCount = 1
repeatIndicator = None
# 2
octetLength = ''
while d and d[0] in '0123456789':
octetLength += d[0]
d = d[1:]
try:
octetLength = int(octetLength)
except Exception:
raise SmiError('Bad octet length: %s' % octetLength)
if not d:
raise SmiError('Short octet length: %s' % self.displayHint)
# 3
displayFormat = d[0]
d = d[1:]
# 4
if d and d[0] not in '0123456789' and d[0] != '*':
displaySep = d[0]
d = d[1:]
else:
displaySep = ''
# 5
if d and displaySep and repeatIndicator is not None:
repeatTerminator = d[0]
displaySep = ''
d = d[1:]
else:
repeatTerminator = None
while repeatCount:
repeatCount -= 1
if displayFormat == 'a':
r += v[:octetLength].decode('ascii', 'ignore')
elif displayFormat == 't':
r += v[:octetLength].decode('utf-8', 'ignore')
elif displayFormat in ('x', 'd', 'o'):
n = 0
vv = v[:octetLength]
while vv:
n <<= 8
try:
n |= octets.oct2int(vv[0])
vv = vv[1:]
except Exception:
raise SmiError(
'Display format eval failure: %s: %s' %
(vv, sys.exc_info()[1]))
if displayFormat == 'x':
r += '%02x' % n
elif displayFormat == 'o':
r += '%03o' % n
else:
r += '%d' % n
else:
raise SmiError('Unsupported display format char: %s' %
displayFormat)
if v and repeatTerminator:
r += repeatTerminator
v = v[octetLength:]
if v and displaySep:
r += displaySep
if not d:
d = self.displayHint
# if d:
# raise SmiError(
# 'Unparsed display hint left: %s' % d
# )
return r
elif self.__objectIdentifier.isSuperTypeOf(self):
return self.__objectIdentifier.prettyOut(value)
elif self.__octetString.isSuperTypeOf(self):
return self.__octetString.prettyOut(value)
else:
return str(value)
def __call__(self, substrate, asn1Spec=None, tagSet=None,
length=None, state=stDecodeTag, recursiveFlag=1):
fullSubstrate = substrate
while state != stStop:
if state == stDecodeTag:
# Decode tag
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on tag decoding'
)
firstOctet = substrate[0]
substrate = substrate[1:]
if firstOctet in self.__tagCache:
lastTag = self.__tagCache[firstOctet]
else:
t = oct2int(firstOctet)
tagClass = t&0xC0
tagFormat = t&0x20
tagId = t&0x1F
if tagId == 0x1F:
tagId = 0
while 1:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on long tag decoding'
)
t = oct2int(substrate[0])
tagId = tagId << 7 | (t&0x7F)
substrate = substrate[1:]
if not t&0x80:
break
lastTag = tag.Tag(
tagClass=tagClass, tagFormat=tagFormat, tagId=tagId
)
if tagId < 31:
# cache short tags
self.__tagCache[firstOctet] = lastTag
if tagSet is None:
if firstOctet in self.__tagSetCache:
tagSet = self.__tagSetCache[firstOctet]
else:
# base tag not recovered
tagSet = tag.TagSet((), lastTag)
if firstOctet in self.__tagCache:
self.__tagSetCache[firstOctet] = tagSet
else:
tagSet = lastTag + tagSet
state = stDecodeLength
if state == stDecodeLength:
# Decode length
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on length decoding'
)
firstOctet = oct2int(substrate[0])
if firstOctet == 128:
size = 1
length = -1
elif firstOctet < 128:
length, size = firstOctet, 1
else:
size = firstOctet & 0x7F
# encoded in size bytes
length = 0
lengthString = substrate[1:size+1]
# missing check on maximum size, which shouldn't be a
# problem, we can handle more than is possible
if len(lengthString) != size:
raise error.SubstrateUnderrunError(
'%s<%s at %s' %
(size, len(lengthString), tagSet)
)
for char in lengthString:
length = (length << 8) | oct2int(char)
size = size + 1
state = stGetValueDecoder
substrate = substrate[size:]
if length != -1 and len(substrate) < length:
raise error.SubstrateUnderrunError(
'%d-octet short' % (length - len(substrate))
)
if state == stGetValueDecoder:
if asn1Spec is None:
state = stGetValueDecoderByTag
else:
state = stGetValueDecoderByAsn1Spec
#
# There're two ways of creating subtypes in ASN.1 what influences
# decoder operation. These methods are:
# 1) Either base types used in or no IMPLICIT tagging has been
# applied on subtyping.
# 2) Subtype syntax drops base type information (by means of
# IMPLICIT tagging.
# The first case allows for complete tag recovery from substrate
# while the second one requires original ASN.1 type spec for
# decoding.
#
# In either case a set of tags (tagSet) is coming from substrate
# in an incremental, tag-by-tag fashion (this is the case of
# EXPLICIT tag which is most basic). Outermost tag comes first
# from the wire.
#
if state == stGetValueDecoderByTag:
if tagSet in self.__tagMap:
concreteDecoder = self.__tagMap[tagSet]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
_k = tagSet[:1]
if _k in self.__tagMap:
concreteDecoder = self.__tagMap[_k]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
state = stTryAsExplicitTag
if state == stGetValueDecoderByAsn1Spec:
if isinstance(asn1Spec, (dict, tagmap.TagMap)):
if tagSet in asn1Spec:
__chosenSpec = asn1Spec[tagSet]
else:
__chosenSpec = None
else:
__chosenSpec = asn1Spec
if __chosenSpec is not None and (
tagSet == __chosenSpec.getTagSet() or \
tagSet in __chosenSpec.getTagMap()
):
# use base type for codec lookup to recover untagged types
baseTagSet = __chosenSpec.baseTagSet
if __chosenSpec.typeId is not None and \
__chosenSpec.typeId in self.__typeMap:
# ambiguous type
concreteDecoder = self.__typeMap[__chosenSpec.typeId]
elif baseTagSet in self.__tagMap:
# base type or tagged subtype
concreteDecoder = self.__tagMap[baseTagSet]
else:
concreteDecoder = None
if concreteDecoder:
asn1Spec = __chosenSpec
state = stDecodeValue
else:
state = stTryAsExplicitTag
elif tagSet == self.__endOfOctetsTagSet:
concreteDecoder = self.__tagMap[tagSet]
state = stDecodeValue
else:
state = stTryAsExplicitTag
if state == stTryAsExplicitTag:
if tagSet and \
tagSet[0][1] == tag.tagFormatConstructed and \
tagSet[0][0] != tag.tagClassUniversal:
# Assume explicit tagging
concreteDecoder = explicitTagDecoder
state = stDecodeValue
else:
state = self.defaultErrorState
if state == stDumpRawValue:
concreteDecoder = self.defaultRawDecoder
state = stDecodeValue
if state == stDecodeValue:
if recursiveFlag:
decodeFun = self
else:
decodeFun = None
if length == -1: # indef length
value, substrate = concreteDecoder.indefLenValueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, decodeFun
)
else:
value, _substrate = concreteDecoder.valueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, decodeFun
)
if recursiveFlag:
substrate = substrate[length:]
else:
substrate = _substrate
state = stStop
if state == stErrorCondition:
raise error.PyAsn1Error(
'%s not in asn1Spec: %s' % (tagSet, repr(asn1Spec))
)
return value, substrate
def test_oct2int(self):
assert 12 == octets.oct2int(bytes([12]))[0]
def prettyOut(self, value): # override asn1 type method
"""Implements DISPLAY-HINT evaluation"""
if self.displayHint and (self.__integer.isSuperTypeOf(self, matchConstraints=False) and not self.getNamedValues() or
self.__unsigned32.isSuperTypeOf(self, matchConstraints=False) or
self.__timeticks.isSuperTypeOf(self, matchConstraints=False)):
_ = lambda t, f=0: (t, f)
displayHintType, decimalPrecision = _(*self.displayHint.split('-'))
if displayHintType == 'x':
return '0x%x' % value
elif displayHintType == 'd':
try:
return '%.*f' % (int(decimalPrecision), float(value) / pow(10, int(decimalPrecision)))
except Exception as exc:
raise SmiError(
'float evaluation error: %s' % exc
)
elif displayHintType == 'o':
return '0%o' % value
elif displayHintType == 'b':
runningValue = value
outputValue = ['B']
while runningValue:
outputValue.insert(0, '%d' % (runningValue & 0x01))
runningValue >>= 1
return ''.join(outputValue)
else:
raise SmiError(
'Unsupported numeric type spec "%s" at %s' % (displayHintType, self.__class__.__name__)
)
elif self.displayHint and self.__octetString.isSuperTypeOf(self, matchConstraints=False):
outputValue = ''
runningValue = OctetString(value).asOctets()
displayHint = self.displayHint
while runningValue and displayHint:
# 1
if displayHint[0] == '*':
repeatIndicator = repeatCount = octets.oct2int(runningValue[0])
displayHint = displayHint[1:]
runningValue = runningValue[1:]
else:
repeatCount = 1
repeatIndicator = None
# 2
octetLength = ''
while displayHint and displayHint[0] in string.digits:
octetLength += displayHint[0]
displayHint = displayHint[1:]
# length is manatory, but people ignore that
if not octetLength:
octetLength = len(runningValue)
try:
octetLength = int(octetLength)
except Exception:
raise SmiError(
'Bad octet length: %s' % octetLength
)
if not displayHint:
raise SmiError(
'Short octet length: %s' % self.displayHint
)
# 3
displayFormat = displayHint[0]
displayHint = displayHint[1:]
# 4
if displayHint and displayHint[0] not in string.digits and displayHint[0] != '*':
displaySep = displayHint[0]
displayHint = displayHint[1:]
else:
displaySep = ''
# 5
if displayHint and displaySep and repeatIndicator is not None:
repeatTerminator = displayHint[0]
displaySep = ''
displayHint = displayHint[1:]
else:
repeatTerminator = None
while repeatCount:
repeatCount -= 1
if displayFormat == 'a':
outputValue += runningValue[:octetLength].decode('ascii', 'ignore')
elif displayFormat == 't':
outputValue += runningValue[:octetLength].decode('utf-8', 'ignore')
elif displayFormat in ('x', 'd', 'o'):
number = 0
numberString = runningValue[:octetLength]
while numberString:
number <<= 8
try:
number |= octets.oct2int(numberString[0])
numberString = numberString[1:]
except Exception as exc:
raise SmiError(
'Display format eval failure: %s: %s'
% (numberString, exc)
)
if displayFormat == 'x':
outputValue += '%02x' % number
elif displayFormat == 'o':
outputValue += '%03o' % number
else:
outputValue += '%d' % number
else:
raise SmiError(
'Unsupported display format char: %s' %
displayFormat
)
if runningValue and repeatTerminator:
outputValue += repeatTerminator
runningValue = runningValue[octetLength:]
if runningValue and displaySep:
outputValue += displaySep
if not displayHint:
displayHint = self.displayHint
return outputValue
for base in inspect.getmro(self.__class__):
if not issubclass(base, TextualConvention) and issubclass(base, Asn1Item):
return base.prettyOut(self, value)
raise SmiError('TEXTUAL-CONVENTION has no underlying SNMP base type')
def __call__(self, substrate, asn1Spec=None, tagSet=None,
length=None, state=stDecodeTag, recursiveFlag=True,
substrateFun=None, allowEoo=False):
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('decoder called at scope %s with state %d, working with up to %d octets of substrate: %s' % (debug.scope, state, len(substrate), debug.hexdump(substrate)))
substrate = ensureString(substrate)
# Look for end-of-octets sentinel
if allowEoo and self.supportIndefLength:
if substrate.startswith(self.__eooSentinel):
debug.logger and debug.logger & debug.flagDecoder and debug.logger('end-of-octets sentinel found')
return eoo.endOfOctets, substrate[2:]
value = base.noValue
fullSubstrate = substrate
while state != stStop:
if state == stDecodeTag:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on tag decoding'
)
# Decode tag
isShortTag = True
firstOctet = substrate[0]
substrate = substrate[1:]
try:
lastTag = self.__tagCache[firstOctet]
except KeyError:
integerTag = oct2int(firstOctet)
tagClass = integerTag & 0xC0
tagFormat = integerTag & 0x20
tagId = integerTag & 0x1F
if tagId == 0x1F:
isShortTag = False
lengthOctetIdx = 0
tagId = 0
try:
while True:
integerTag = oct2int(substrate[lengthOctetIdx])
lengthOctetIdx += 1
tagId <<= 7
tagId |= (integerTag & 0x7F)
if not integerTag & 0x80:
break
substrate = substrate[lengthOctetIdx:]
except IndexError:
raise error.SubstrateUnderrunError(
'Short octet stream on long tag decoding'
)
lastTag = tag.Tag(
tagClass=tagClass, tagFormat=tagFormat, tagId=tagId
)
if isShortTag:
# cache short tags
self.__tagCache[firstOctet] = lastTag
if tagSet is None:
if isShortTag:
try:
tagSet = self.__tagSetCache[firstOctet]
except KeyError:
# base tag not recovered
tagSet = tag.TagSet((), lastTag)
self.__tagSetCache[firstOctet] = tagSet
else:
tagSet = tag.TagSet((), lastTag)
else:
tagSet = lastTag + tagSet
state = stDecodeLength
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'tag decoded into %s, decoding length' % tagSet)
if state == stDecodeLength:
# Decode length
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on length decoding'
)
firstOctet = oct2int(substrate[0])
if firstOctet < 128:
size = 1
length = firstOctet
elif firstOctet == 128:
size = 1
length = -1
else:
size = firstOctet & 0x7F
# encoded in size bytes
encodedLength = octs2ints(substrate[1:size + 1])
# missing check on maximum size, which shouldn't be a
# problem, we can handle more than is possible
if len(encodedLength) != size:
raise error.SubstrateUnderrunError(
'%s<%s at %s' % (size, len(encodedLength), tagSet)
)
length = 0
for lengthOctet in encodedLength:
length <<= 8
length |= lengthOctet
size += 1
substrate = substrate[size:]
if length == -1:
if not self.supportIndefLength:
raise error.PyAsn1Error('Indefinite length encoding not supported by this codec')
else:
if len(substrate) < length:
raise error.SubstrateUnderrunError('%d-octet short' % (length - len(substrate)))
state = stGetValueDecoder
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'value length decoded into %d, payload substrate is: %s' % (length, debug.hexdump(length == -1 and substrate or substrate[:length]))
)
if state == stGetValueDecoder:
if asn1Spec is None:
state = stGetValueDecoderByTag
else:
state = stGetValueDecoderByAsn1Spec
#
# There're two ways of creating subtypes in ASN.1 what influences
# decoder operation. These methods are:
# 1) Either base types used in or no IMPLICIT tagging has been
# applied on subtyping.
# 2) Subtype syntax drops base type information (by means of
# IMPLICIT tagging.
# The first case allows for complete tag recovery from substrate
# while the second one requires original ASN.1 type spec for
# decoding.
#
# In either case a set of tags (tagSet) is coming from substrate
# in an incremental, tag-by-tag fashion (this is the case of
# EXPLICIT tag which is most basic). Outermost tag comes first
# from the wire.
#
if state == stGetValueDecoderByTag:
try:
concreteDecoder = self.__tagMap[tagSet]
except KeyError:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
try:
concreteDecoder = self.__tagMap[tagSet[:1]]
except KeyError:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
state = stTryAsExplicitTag
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('codec %s chosen by a built-in type, decoding %s' % (concreteDecoder and concreteDecoder.__class__.__name__ or "<none>", state == stDecodeValue and 'value' or 'as explicit tag'))
debug.scope.push(
concreteDecoder is None and '?' or concreteDecoder.protoComponent.__class__.__name__)
if state == stGetValueDecoderByAsn1Spec:
if asn1Spec.__class__ is dict or asn1Spec.__class__ is tagmap.TagMap:
try:
chosenSpec = asn1Spec[tagSet]
except KeyError:
chosenSpec = None
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('candidate ASN.1 spec is a map of:')
for firstOctet, v in asn1Spec.presentTypes.items():
debug.logger(' %s -> %s' % (firstOctet, v.__class__.__name__))
if asn1Spec.skipTypes:
debug.logger('but neither of: ')
for firstOctet, v in asn1Spec.skipTypes.items():
debug.logger(' %s -> %s' % (firstOctet, v.__class__.__name__))
debug.logger('new candidate ASN.1 spec is %s, chosen by %s' % (chosenSpec is None and '<none>' or chosenSpec.prettyPrintType(), tagSet))
else:
if tagSet == asn1Spec.tagSet or tagSet in asn1Spec.tagMap:
chosenSpec = asn1Spec
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'candidate ASN.1 spec is %s' % asn1Spec.__class__.__name__)
else:
chosenSpec = None
if chosenSpec is not None:
try:
# ambiguous type or just faster codec lookup
concreteDecoder = self.__typeMap[chosenSpec.typeId]
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'value decoder chosen for an ambiguous type by type ID %s' % (chosenSpec.typeId,))
except KeyError:
# use base type for codec lookup to recover untagged types
baseTagSet = tag.TagSet(chosenSpec.tagSet.baseTag, chosenSpec.tagSet.baseTag)
try:
# base type or tagged subtype
concreteDecoder = self.__tagMap[baseTagSet]
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'value decoder chosen by base %s' % (baseTagSet,))
except KeyError:
concreteDecoder = None
if concreteDecoder:
asn1Spec = chosenSpec
state = stDecodeValue
else:
state = stTryAsExplicitTag
else:
concreteDecoder = None
state = stTryAsExplicitTag
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('codec %s chosen by ASN.1 spec, decoding %s' % (state == stDecodeValue and concreteDecoder.__class__.__name__ or "<none>", state == stDecodeValue and 'value' or 'as explicit tag'))
debug.scope.push(chosenSpec is None and '?' or chosenSpec.__class__.__name__)
if state == stTryAsExplicitTag:
if tagSet and tagSet[0].tagFormat == tag.tagFormatConstructed and tagSet[0].tagClass != tag.tagClassUniversal:
# Assume explicit tagging
concreteDecoder = explicitTagDecoder
state = stDecodeValue
else:
concreteDecoder = None
state = self.defaultErrorState
debug.logger and debug.logger & debug.flagDecoder and debug.logger('codec %s chosen, decoding %s' % (concreteDecoder and concreteDecoder.__class__.__name__ or "<none>", state == stDecodeValue and 'value' or 'as failure'))
if state == stDumpRawValue:
concreteDecoder = self.defaultRawDecoder
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'codec %s chosen, decoding value' % concreteDecoder.__class__.__name__)
state = stDecodeValue
if state == stDecodeValue:
if not recursiveFlag and not substrateFun: # legacy
def substrateFun(a, b, c):
return a, b[:c]
if length == -1: # indef length
value, substrate = concreteDecoder.indefLenValueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun
)
else:
value, substrate = concreteDecoder.valueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun
)
state = stStop
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'codec %s yields type %s, value:\n%s\n...remaining substrate is: %s' % (concreteDecoder.__class__.__name__, value.__class__.__name__, value.prettyPrint(), substrate and debug.hexdump(substrate) or '<none>'))
if state == stErrorCondition:
raise error.PyAsn1Error(
'%s not in asn1Spec: %s' % (tagSet, asn1Spec)
)
if debug.logger and debug.logger & debug.flagDecoder:
debug.scope.pop()
debug.logger('decoder left scope %s, call completed' % debug.scope)
return value, substrate
def __call__(self,
substrate,
asn1Spec=None,
tagSet=None,
length=None,
state=stDecodeTag,
recursiveFlag=True,
substrateFun=None,
allowEoo=False):
if debug.logger & debug.flagDecoder:
logger = debug.logger
else:
logger = None
if logger:
logger(
'decoder called at scope %s with state %d, working with up to %d octets of substrate: %s'
%
(debug.scope, state, len(substrate), debug.hexdump(substrate)))
substrate = ensureString(substrate)
# Look for end-of-octets sentinel
if allowEoo and self.supportIndefLength:
if substrate.startswith(self.__eooSentinel):
if logger:
logger('end-of-octets sentinel found')
return eoo.endOfOctets, substrate[2:]
value = base.noValue
fullSubstrate = substrate
while not state is stStop:
if state is stDecodeTag:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on tag decoding')
# Decode tag
isShortTag = True
firstOctet = substrate[0]
substrate = substrate[1:]
try:
lastTag = self.__tagCache[firstOctet]
except KeyError:
integerTag = oct2int(firstOctet)
tagClass = integerTag & 0xC0
tagFormat = integerTag & 0x20
tagId = integerTag & 0x1F
if tagId == 0x1F:
isShortTag = False
lengthOctetIdx = 0
tagId = 0
try:
while True:
integerTag = oct2int(substrate[lengthOctetIdx])
lengthOctetIdx += 1
tagId <<= 7
tagId |= (integerTag & 0x7F)
if not integerTag & 0x80:
break
substrate = substrate[lengthOctetIdx:]
except IndexError:
raise error.SubstrateUnderrunError(
'Short octet stream on long tag decoding')
lastTag = tag.Tag(tagClass=tagClass,
tagFormat=tagFormat,
tagId=tagId)
if isShortTag:
# cache short tags
self.__tagCache[firstOctet] = lastTag
if tagSet is None:
if isShortTag:
try:
tagSet = self.__tagSetCache[firstOctet]
except KeyError:
# base tag not recovered
tagSet = tag.TagSet((), lastTag)
self.__tagSetCache[firstOctet] = tagSet
else:
tagSet = tag.TagSet((), lastTag)
else:
tagSet = lastTag + tagSet
state = stDecodeLength
if logger:
logger('tag decoded into %s, decoding length' % tagSet)
if state is stDecodeLength:
# Decode length
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on length decoding')
firstOctet = oct2int(substrate[0])
if firstOctet < 128:
size = 1
length = firstOctet
elif firstOctet == 128:
size = 1
length = -1
else:
size = firstOctet & 0x7F
# encoded in size bytes
encodedLength = octs2ints(substrate[1:size + 1])
# missing check on maximum size, which shouldn't be a
# problem, we can handle more than is possible
if len(encodedLength) != size:
raise error.SubstrateUnderrunError(
'%s<%s at %s' % (size, len(encodedLength), tagSet))
length = 0
for lengthOctet in encodedLength:
length <<= 8
length |= lengthOctet
size += 1
substrate = substrate[size:]
if length == -1:
if not self.supportIndefLength:
raise error.PyAsn1Error(
'Indefinite length encoding not supported by this codec'
)
else:
if len(substrate) < length:
raise error.SubstrateUnderrunError(
'%d-octet short' % (length - len(substrate)))
state = stGetValueDecoder
if logger:
logger(
'value length decoded into %d, payload substrate is: %s'
% (length,
debug.hexdump(length == -1 and substrate
or substrate[:length])))
if state is stGetValueDecoder:
if asn1Spec is None:
state = stGetValueDecoderByTag
else:
state = stGetValueDecoderByAsn1Spec
#
# There're two ways of creating subtypes in ASN.1 what influences
# decoder operation. These methods are:
# 1) Either base types used in or no IMPLICIT tagging has been
# applied on subtyping.
# 2) Subtype syntax drops base type information (by means of
# IMPLICIT tagging.
# The first case allows for complete tag recovery from substrate
# while the second one requires original ASN.1 type spec for
# decoding.
#
# In either case a set of tags (tagSet) is coming from substrate
# in an incremental, tag-by-tag fashion (this is the case of
# EXPLICIT tag which is most basic). Outermost tag comes first
# from the wire.
#
if state is stGetValueDecoderByTag:
try:
concreteDecoder = self.__tagMap[tagSet]
except KeyError:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
try:
concreteDecoder = self.__tagMap[tagSet[:1]]
except KeyError:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
state = stTryAsExplicitTag
if logger:
logger(
'codec %s chosen by a built-in type, decoding %s' %
(concreteDecoder and concreteDecoder.__class__.__name__
or "<none>", state is stDecodeValue and 'value'
or 'as explicit tag'))
debug.scope.push(
concreteDecoder is None and '?'
or concreteDecoder.protoComponent.__class__.__name__)
if state is stGetValueDecoderByAsn1Spec:
if asn1Spec.__class__ is dict or asn1Spec.__class__ is tagmap.TagMap:
try:
chosenSpec = asn1Spec[tagSet]
except KeyError:
chosenSpec = None
if logger:
logger('candidate ASN.1 spec is a map of:')
for firstOctet, v in asn1Spec.presentTypes.items():
logger(' %s -> %s' %
(firstOctet, v.__class__.__name__))
if asn1Spec.skipTypes:
logger('but neither of: ')
for firstOctet, v in asn1Spec.skipTypes.items():
logger(' %s -> %s' %
(firstOctet, v.__class__.__name__))
logger('new candidate ASN.1 spec is %s, chosen by %s' %
(chosenSpec is None and '<none>'
or chosenSpec.prettyPrintType(), tagSet))
else:
if tagSet == asn1Spec.tagSet or tagSet in asn1Spec.tagMap:
chosenSpec = asn1Spec
if logger:
logger('candidate ASN.1 spec is %s' %
asn1Spec.__class__.__name__)
else:
chosenSpec = None
if chosenSpec is not None:
try:
# ambiguous type or just faster codec lookup
concreteDecoder = self.__typeMap[chosenSpec.typeId]
if logger:
logger(
'value decoder chosen for an ambiguous type by type ID %s'
% (chosenSpec.typeId, ))
except KeyError:
# use base type for codec lookup to recover untagged types
baseTagSet = tag.TagSet(chosenSpec.tagSet.baseTag,
chosenSpec.tagSet.baseTag)
try:
# base type or tagged subtype
concreteDecoder = self.__tagMap[baseTagSet]
if logger:
logger('value decoder chosen by base %s' %
(baseTagSet, ))
except KeyError:
concreteDecoder = None
if concreteDecoder:
asn1Spec = chosenSpec
state = stDecodeValue
else:
state = stTryAsExplicitTag
else:
concreteDecoder = None
state = stTryAsExplicitTag
if logger:
logger('codec %s chosen by ASN.1 spec, decoding %s' %
(state is stDecodeValue
and concreteDecoder.__class__.__name__
or "<none>", state is stDecodeValue and 'value'
or 'as explicit tag'))
debug.scope.push(chosenSpec is None and '?'
or chosenSpec.__class__.__name__)
if state is stTryAsExplicitTag:
if tagSet and tagSet[
0].tagFormat == tag.tagFormatConstructed and tagSet[
0].tagClass != tag.tagClassUniversal:
# Assume explicit tagging
concreteDecoder = explicitTagDecoder
state = stDecodeValue
else:
concreteDecoder = None
state = self.defaultErrorState
if logger:
logger(
'codec %s chosen, decoding %s' %
(concreteDecoder and concreteDecoder.__class__.__name__
or "<none>", state is stDecodeValue and 'value'
or 'as failure'))
if state is stDumpRawValue:
concreteDecoder = self.defaultRawDecoder
if logger:
logger('codec %s chosen, decoding value' %
concreteDecoder.__class__.__name__)
state = stDecodeValue
if state is stDecodeValue:
if not recursiveFlag and not substrateFun: # legacy
def substrateFun(a, b, c):
return a, b[:c]
if length == -1: # indef length
value, substrate = concreteDecoder.indefLenValueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun)
else:
value, substrate = concreteDecoder.valueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun)
state = stStop
if logger:
logger(
'codec %s yields type %s, value:\n%s\n...remaining substrate is: %s'
% (concreteDecoder.__class__.__name__,
value.__class__.__name__, value.prettyPrint(),
substrate and debug.hexdump(substrate) or '<none>'))
if state is stErrorCondition:
raise error.PyAsn1Error('%s not in asn1Spec: %r' %
(tagSet, asn1Spec))
if logger:
debug.scope.pop()
logger('decoder left scope %s, call completed' % debug.scope)
return value, substrate
def __call__(self, substrate, asn1Spec=None, tagSet=None,
length=None, state=stDecodeTag, recursiveFlag=1,
substrateFun=None, allowEoo=False):
if debug.logger & debug.flagDecoder:
debug.logger('decoder called at scope %s with state %d, working with up to %d octets of substrate: %s' % (debug.scope, state, len(substrate), debug.hexdump(substrate)))
if asn1Spec is not None and not isinstance(asn1Spec, (base.Asn1Item, tagmap.TagMap)):
raise error.PyAsn1Error('asn1Spec is not valid (should be an instance of an ASN.1 Item, not %s)' % asn1Spec.__class__.__name__)
fullSubstrate = substrate
while state != stStop:
if state == stDecodeTag:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on tag decoding'
)
if not isOctetsType(substrate) and \
not isinstance(substrate, univ.OctetString):
raise error.PyAsn1Error('Bad octet stream type')
# Decode tag
firstOctet = substrate[0]
substrate = substrate[1:]
if firstOctet in self.__tagCache:
lastTag = self.__tagCache[firstOctet]
else:
t = oct2int(firstOctet)
# Look for end-of-octets sentinel
if t == 0:
if substrate and oct2int(substrate[0]) == 0:
if allowEoo and self.supportIndefLength:
debug.logger and debug.logger & debug.flagDecoder and debug.logger('end-of-octets sentinel found')
value, substrate = eoo.endOfOctets, substrate[1:]
state = stStop
continue
else:
raise error.PyAsn1Error('Unexpected end-of-contents sentinel')
else:
raise error.PyAsn1Error('Zero tag encountered')
tagClass = t&0xC0
tagFormat = t&0x20
tagId = t&0x1F
if tagId == 0x1F:
tagId = 0
while 1:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on long tag decoding'
)
t = oct2int(substrate[0])
tagId = tagId << 7 | (t&0x7F)
substrate = substrate[1:]
if not t&0x80:
break
lastTag = tag.Tag(
tagClass=tagClass, tagFormat=tagFormat, tagId=tagId
)
if tagId < 31:
# cache short tags
self.__tagCache[firstOctet] = lastTag
if tagSet is None:
if firstOctet in self.__tagSetCache:
tagSet = self.__tagSetCache[firstOctet]
else:
# base tag not recovered
tagSet = tag.TagSet((), lastTag)
if firstOctet in self.__tagCache:
self.__tagSetCache[firstOctet] = tagSet
else:
tagSet = lastTag + tagSet
state = stDecodeLength
debug.logger and debug.logger & debug.flagDecoder and debug.logger('tag decoded into %s, decoding length' % tagSet)
if state == stDecodeLength:
# Decode length
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on length decoding'
)
firstOctet = oct2int(substrate[0])
if firstOctet == 128:
size = 1
length = -1
elif firstOctet < 128:
length, size = firstOctet, 1
else:
size = firstOctet & 0x7F
# encoded in size bytes
length = 0
lengthString = substrate[1:size+1]
# missing check on maximum size, which shouldn't be a
# problem, we can handle more than is possible
if len(lengthString) != size:
raise error.SubstrateUnderrunError(
'%s<%s at %s' %
(size, len(lengthString), tagSet)
)
for char in lengthString:
length = (length << 8) | oct2int(char)
size += 1
substrate = substrate[size:]
if length != -1 and len(substrate) < length:
raise error.SubstrateUnderrunError(
'%d-octet short' % (length - len(substrate))
)
if length == -1 and not self.supportIndefLength:
error.PyAsn1Error('Indefinite length encoding not supported by this codec')
state = stGetValueDecoder
debug.logger and debug.logger & debug.flagDecoder and debug.logger('value length decoded into %d, payload substrate is: %s' % (length, debug.hexdump(length == -1 and substrate or substrate[:length])))
if state == stGetValueDecoder:
if asn1Spec is None:
state = stGetValueDecoderByTag
else:
state = stGetValueDecoderByAsn1Spec
#
# There're two ways of creating subtypes in ASN.1 what influences
# decoder operation. These methods are:
# 1) Either base types used in or no IMPLICIT tagging has been
# applied on subtyping.
# 2) Subtype syntax drops base type information (by means of
# IMPLICIT tagging.
# The first case allows for complete tag recovery from substrate
# while the second one requires original ASN.1 type spec for
# decoding.
#
# In either case a set of tags (tagSet) is coming from substrate
# in an incremental, tag-by-tag fashion (this is the case of
# EXPLICIT tag which is most basic). Outermost tag comes first
# from the wire.
#
if state == stGetValueDecoderByTag:
if tagSet in self.__tagMap:
concreteDecoder = self.__tagMap[tagSet]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
_k = tagSet[:1]
if _k in self.__tagMap:
concreteDecoder = self.__tagMap[_k]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
state = stTryAsExplicitTag
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('codec %s chosen by a built-in type, decoding %s' % (concreteDecoder and concreteDecoder.__class__.__name__ or "<none>", state == stDecodeValue and 'value' or 'as explicit tag'))
debug.scope.push(concreteDecoder is None and '?' or concreteDecoder.protoComponent.__class__.__name__)
if state == stGetValueDecoderByAsn1Spec:
if isinstance(asn1Spec, (dict, tagmap.TagMap)):
if tagSet in asn1Spec:
__chosenSpec = asn1Spec[tagSet]
else:
__chosenSpec = None
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('candidate ASN.1 spec is a map of:')
for t, v in asn1Spec.getPosMap().items():
debug.logger(' %s -> %s' % (t, v.__class__.__name__))
if asn1Spec.getNegMap():
debug.logger('but neither of: ')
for t, v in asn1Spec.getNegMap().items():
debug.logger(' %s -> %s' % (t, v.__class__.__name__))
debug.logger('new candidate ASN.1 spec is %s, chosen by %s' % (__chosenSpec is None and '<none>' or __chosenSpec.prettyPrintType(), tagSet))
else:
__chosenSpec = asn1Spec
debug.logger and debug.logger & debug.flagDecoder and debug.logger('candidate ASN.1 spec is %s' % asn1Spec.__class__.__name__)
if __chosenSpec is not None and (
tagSet == __chosenSpec.getTagSet() or \
tagSet in __chosenSpec.getTagMap()
):
# use base type for codec lookup to recover untagged types
baseTagSet = __chosenSpec.baseTagSet
if __chosenSpec.typeId is not None and \
__chosenSpec.typeId in self.__typeMap:
# ambiguous type
concreteDecoder = self.__typeMap[__chosenSpec.typeId]
debug.logger and debug.logger & debug.flagDecoder and debug.logger('value decoder chosen for an ambiguous type by type ID %s' % (__chosenSpec.typeId,))
elif baseTagSet in self.__tagMap:
# base type or tagged subtype
concreteDecoder = self.__tagMap[baseTagSet]
debug.logger and debug.logger & debug.flagDecoder and debug.logger('value decoder chosen by base %s' % (baseTagSet,))
else:
concreteDecoder = None
if concreteDecoder:
asn1Spec = __chosenSpec
state = stDecodeValue
else:
state = stTryAsExplicitTag
else:
concreteDecoder = None
state = stTryAsExplicitTag
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('codec %s chosen by ASN.1 spec, decoding %s' % (state == stDecodeValue and concreteDecoder.__class__.__name__ or "<none>", state == stDecodeValue and 'value' or 'as explicit tag'))
debug.scope.push(__chosenSpec is None and '?' or __chosenSpec.__class__.__name__)
if state == stTryAsExplicitTag:
if tagSet and \
tagSet[0][1] == tag.tagFormatConstructed and \
tagSet[0][0] != tag.tagClassUniversal:
# Assume explicit tagging
concreteDecoder = explicitTagDecoder
state = stDecodeValue
else:
concreteDecoder = None
state = self.defaultErrorState
debug.logger and debug.logger & debug.flagDecoder and debug.logger('codec %s chosen, decoding %s' % (concreteDecoder and concreteDecoder.__class__.__name__ or "<none>", state == stDecodeValue and 'value' or 'as failure'))
if state == stDumpRawValue:
concreteDecoder = self.defaultRawDecoder
debug.logger and debug.logger & debug.flagDecoder and debug.logger('codec %s chosen, decoding value' % concreteDecoder.__class__.__name__)
state = stDecodeValue
if state == stDecodeValue:
if recursiveFlag == 0 and not substrateFun: # legacy
substrateFun = lambda a,b,c: (a,b[:c])
if length == -1: # indef length
value, substrate = concreteDecoder.indefLenValueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun
)
else:
value, substrate = concreteDecoder.valueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun
)
state = stStop
debug.logger and debug.logger & debug.flagDecoder and debug.logger('codec %s yields type %s, value:\n%s\n...remaining substrate is: %s' % (concreteDecoder.__class__.__name__, value.__class__.__name__, value.prettyPrint(), substrate and debug.hexdump(substrate) or '<none>'))
if state == stErrorCondition:
raise error.PyAsn1Error(
'%s not in asn1Spec: %s' % (tagSet, asn1Spec)
)
if debug.logger and debug.logger & debug.flagDecoder:
debug.scope.pop()
debug.logger('decoder left scope %s, call completed' % debug.scope)
return value, substrate
def test_oct2int(self):
assert 12 == octets.oct2int('\x0c')
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
if value.isPlusInfinity():
return int2oct(0x40), 0
if value.isMinusInfinity():
return int2oct(0x41), 0
m, b, e = value
if not m:
return null, 0
if b == 10:
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), 0
elif b == 2:
fo = 0x80 # binary encoding
ms, m, encbase, e = self._chooseEncBase(value)
if ms < 0: # mantissa sign
fo = fo | 0x40 # sign bit
# exponenta & mantissa normalization
if encbase == 2:
while m & 0x1 == 0:
m >>= 1
e += 1
elif encbase == 8:
while m & 0x7 == 0:
m >>= 3
e += 1
fo |= 0x10
else: # encbase = 16
while m & 0xf == 0:
m >>= 4
e += 1
fo |= 0x20
sf = 0 # scale factor
while m & 0x1 == 0:
m >>= 1
sf += 1
if sf > 3:
raise error.PyAsn1Error('Scale factor overflow') # bug if raised
fo |= sf << 2
eo = null
if e == 0 or e == -1:
eo = int2oct(e&0xff)
else:
while e not in (0, -1):
eo = int2oct(e&0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
if e == -1 and eo and not (oct2int(eo[0]) & 0x80):
eo = int2oct(0xff) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n&0xff) + eo
po = null
while m:
po = int2oct(m&0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, 0
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
def test_oct2int(self):
assert 12 == octets.oct2int('\x0c')
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
if value.isPlusInfinity():
return int2oct(0x40), 0
if value.isMinusInfinity():
return int2oct(0x41), 0
m, b, e = value
if not m:
return null, 0
if b == 10:
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), 0
elif b == 2:
fo = 0x80 # binary encoding
ms, m, encbase, e = self._chooseEncBase(value)
if ms < 0: # mantissa sign
fo = fo | 0x40 # sign bit
# exponenta & mantissa normalization
if encbase == 2:
while m & 0x1 == 0:
m >>= 1
e += 1
elif encbase == 8:
while m & 0x7 == 0:
m >>= 3
e += 1
fo |= 0x10
else: # encbase = 16
while m & 0xf == 0:
m >>= 4
e += 1
fo |= 0x20
sf = 0 # scale factor
while m & 0x1 == 0:
m >>= 1
sf += 1
if sf > 3:
raise error.PyAsn1Error(
'Scale factor overflow') # bug if raised
fo |= sf << 2
eo = null
if e == 0 or e == -1:
eo = int2oct(e & 0xff)
else:
while e not in (0, -1):
eo = int2oct(e & 0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
if e == -1 and eo and not (oct2int(eo[0]) & 0x80):
eo = int2oct(0xff) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n & 0xff) + eo
po = null
while m:
po = int2oct(m & 0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, 0
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
def encodeValue(self, value, asn1Spec, encodeFun, **options):
if asn1Spec is not None:
value = asn1Spec.clone(value)
if value.isPlusInf:
return (0x40, ), False, False
if value.isMinusInf:
return (0x41, ), False, False
m, b, e = value
if not m:
return null, False, True
if b == 10:
if LOG:
LOG('encoding REAL into character form')
return str2octs('\x03%dE%s%d' %
(m, e == 0 and '+' or '', e)), False, True
elif b == 2:
fo = 0x80 # binary encoding
ms, m, encbase, e = self._chooseEncBase(value)
if ms < 0: # mantissa sign
fo |= 0x40 # sign bit
# exponent & mantissa normalization
if encbase == 2:
while m & 0x1 == 0:
m >>= 1
e += 1
elif encbase == 8:
while m & 0x7 == 0:
m >>= 3
e += 1
fo |= 0x10
else: # encbase = 16
while m & 0xf == 0:
m >>= 4
e += 1
fo |= 0x20
sf = 0 # scale factor
while m & 0x1 == 0:
m >>= 1
sf += 1
if sf > 3:
raise error.PyAsn1Error(
'Scale factor overflow') # bug if raised
fo |= sf << 2
eo = null
if e == 0 or e == -1:
eo = int2oct(e & 0xff)
else:
while e not in (0, -1):
eo = int2oct(e & 0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
if e == -1 and eo and not (oct2int(eo[0]) & 0x80):
eo = int2oct(0xff) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n & 0xff) + eo
po = null
while m:
po = int2oct(m & 0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, False, True
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
def prettyOut(self, value): # override asn1 type method
"""Implements DISPLAY-HINT evaluation"""
if self.displayHint and (self.__integer.isSuperTypeOf(self) or
self.__unsigned32.isSuperTypeOf(self) or
self.__timeticks.isSuperTypeOf(self) or
self.__counter32.isSuperTypeOf(self) or
self.__counter64.isSuperTypeOf(self)):
_ = lambda t, f=0: (t, f)
t, f = _(*self.displayHint.split('-'))
if t == 'x':
return '0x%x' % value
elif t == 'd':
try:
return '%.*f' % (int(f), float(value) / pow(10, int(f)))
except Exception:
raise SmiError(
'float num evaluation error: %s' % sys.exc_info()[1]
)
elif t == 'o':
return '0%o' % value
elif t == 'b':
v = value
r = ['B']
while v:
r.insert(0, '%d' % (v & 0x01))
v >>= 1
return ''.join(r)
else:
raise SmiError(
'Unsupported numeric type spec: %s' % t
)
elif self.displayHint and self.__octetString.isSuperTypeOf(self):
r = ''
v = self.__class__(value).asOctets()
d = self.displayHint
while v and d:
# 1
if d[0] == '*':
repeatIndicator = repeatCount = octets.oct2int(v[0])
d = d[1:]
v = v[1:]
else:
repeatCount = 1
repeatIndicator = None
# 2
octetLength = ''
while d and d[0] in '0123456789':
octetLength += d[0]
d = d[1:]
try:
octetLength = int(octetLength)
except Exception:
raise SmiError(
'Bad octet length: %s' % octetLength
)
if not d:
raise SmiError(
'Short octet length: %s' % self.displayHint
)
# 3
displayFormat = d[0]
d = d[1:]
# 4
if d and d[0] not in '0123456789' and d[0] != '*':
displaySep = d[0]
d = d[1:]
else:
displaySep = ''
# 5
if d and displaySep and repeatIndicator is not None:
repeatTerminator = d[0]
displaySep = ''
d = d[1:]
else:
repeatTerminator = None
while repeatCount:
repeatCount -= 1
if displayFormat == 'a':
r += v[:octetLength].decode('ascii', 'ignore')
elif displayFormat == 't':
r += v[:octetLength].decode('utf-8', 'ignore')
elif displayFormat in ('x', 'd', 'o'):
n = 0
vv = v[:octetLength]
while vv:
n <<= 8
try:
n |= octets.oct2int(vv[0])
vv = vv[1:]
except Exception:
raise SmiError(
'Display format eval failure: %s: %s'
% (vv, sys.exc_info()[1])
)
if displayFormat == 'x':
r += '%02x' % n
elif displayFormat == 'o':
r += '%03o' % n
else:
r += '%d' % n
else:
raise SmiError(
'Unsupported display format char: %s' %
displayFormat
)
if v and repeatTerminator:
r += repeatTerminator
v = v[octetLength:]
if v and displaySep:
r += displaySep
if not d:
d = self.displayHint
# if d:
# raise SmiError(
# 'Unparsed display hint left: %s' % d
# )
return r
elif self.__objectIdentifier.isSuperTypeOf(self):
return self.__objectIdentifier.prettyOut(value)
elif self.__octetString.isSuperTypeOf(self):
return self.__octetString.prettyOut(value)
else:
return str(value)
def __call__(self, substrate, asn1Spec=None, tagSet=None,
length=None, state=stDecodeTag, recursiveFlag=1):
fullSubstrate = substrate
while state != stStop:
if state == stDecodeTag:
# Decode tag
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on tag decoding'
)
firstOctet = substrate[0]
substrate = substrate[1:]
if firstOctet in self.__tagCache:
lastTag = self.__tagCache[firstOctet]
else:
t = oct2int(firstOctet)
tagClass = t&0xC0
tagFormat = t&0x20
tagId = t&0x1F
if tagId == 0x1F:
tagId = 0
while 1:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on long tag decoding'
)
t = oct2int(substrate[0])
tagId = tagId << 7 | (t&0x7F)
substrate = substrate[1:]
if not t&0x80:
break
lastTag = tag.Tag(
tagClass=tagClass, tagFormat=tagFormat, tagId=tagId
)
if tagId < 31:
# cache short tags
self.__tagCache[firstOctet] = lastTag
if tagSet is None:
if firstOctet in self.__tagSetCache:
tagSet = self.__tagSetCache[firstOctet]
else:
# base tag not recovered
tagSet = tag.TagSet((), lastTag)
if firstOctet in self.__tagCache:
self.__tagSetCache[firstOctet] = tagSet
else:
tagSet = lastTag + tagSet
state = stDecodeLength
if state == stDecodeLength:
# Decode length
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on length decoding'
)
firstOctet = oct2int(substrate[0])
if firstOctet == 128:
size = 1
length = -1
elif firstOctet < 128:
length, size = firstOctet, 1
else:
size = firstOctet & 0x7F
# encoded in size bytes
length = 0
lengthString = substrate[1:size+1]
# missing check on maximum size, which shouldn't be a
# problem, we can handle more than is possible
if len(lengthString) != size:
raise error.SubstrateUnderrunError(
'%s<%s at %s' %
(size, len(lengthString), tagSet)
)
for char in lengthString:
length = (length << 8) | oct2int(char)
size = size + 1
state = stGetValueDecoder
substrate = substrate[size:]
if length != -1 and len(substrate) < length:
raise error.SubstrateUnderrunError(
'%d-octet short' % (length - len(substrate))
)
if state == stGetValueDecoder:
if asn1Spec is None:
state = stGetValueDecoderByTag
else:
state = stGetValueDecoderByAsn1Spec
#
# There're two ways of creating subtypes in ASN.1 what influences
# decoder operation. These methods are:
# 1) Either base types used in or no IMPLICIT tagging has been
# applied on subtyping.
# 2) Subtype syntax drops base type information (by means of
# IMPLICIT tagging.
# The first case allows for complete tag recovery from substrate
# while the second one requires original ASN.1 type spec for
# decoding.
#
# In either case a set of tags (tagSet) is coming from substrate
# in an incremental, tag-by-tag fashion (this is the case of
# EXPLICIT tag which is most basic). Outermost tag comes first
# from the wire.
#
if state == stGetValueDecoderByTag:
if tagSet in self.__tagMap:
concreteDecoder = self.__tagMap[tagSet]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
_k = tagSet[:1]
if _k in self.__tagMap:
concreteDecoder = self.__tagMap[_k]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
state = stTryAsExplicitTag
if state == stGetValueDecoderByAsn1Spec:
if isinstance(asn1Spec, (dict, tagmap.TagMap)):
if tagSet in asn1Spec:
__chosenSpec = asn1Spec[tagSet]
else:
__chosenSpec = None
else:
__chosenSpec = asn1Spec
if __chosenSpec is not None and (
tagSet == __chosenSpec.getTagSet() or \
tagSet in __chosenSpec.getTagMap()
):
# use base type for codec lookup to recover untagged types
baseTagSet = __chosenSpec.baseTagSet
if __chosenSpec.typeId is not None and \
__chosenSpec.typeId in self.__typeMap:
# ambiguous type
concreteDecoder = self.__typeMap[__chosenSpec.typeId]
elif baseTagSet in self.__tagMap:
# base type or tagged subtype
concreteDecoder = self.__tagMap[baseTagSet]
else:
concreteDecoder = None
if concreteDecoder:
asn1Spec = __chosenSpec
state = stDecodeValue
else:
state = stTryAsExplicitTag
elif tagSet == self.__endOfOctetsTagSet:
concreteDecoder = self.__tagMap[tagSet]
state = stDecodeValue
else:
state = stTryAsExplicitTag
if state == stTryAsExplicitTag:
if tagSet and \
tagSet[0][1] == tag.tagFormatConstructed and \
tagSet[0][0] != tag.tagClassUniversal:
# Assume explicit tagging
concreteDecoder = explicitTagDecoder
state = stDecodeValue
else:
state = self.defaultErrorState
if state == stDumpRawValue:
concreteDecoder = self.defaultRawDecoder
state = stDecodeValue
if state == stDecodeValue:
if recursiveFlag:
decodeFun = self
else:
decodeFun = None
if length == -1: # indef length
value, substrate = concreteDecoder.indefLenValueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, decodeFun
)
else:
value, _substrate = concreteDecoder.valueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, decodeFun
)
if recursiveFlag:
substrate = substrate[length:]
else:
substrate = _substrate
state = stStop
if state == stErrorCondition:
raise error.PyAsn1Error(
'%s not in asn1Spec: %s' % (tagSet, repr(asn1Spec))
)
return value, substrate
def prettyOut(self, value): # override asn1 type method
"""Implements DISPLAY-HINT evaluation"""
if self.displayHint and (self.__integer.isSuperTypeOf(
self, matchConstraints=False) and not self.getNamedValues()
or self.__unsigned32.isSuperTypeOf(
self, matchConstraints=False)
or self.__timeticks.isSuperTypeOf(
self, matchConstraints=False)):
_ = lambda t, f=0: (t, f)
displayHintType, decimalPrecision = _(*self.displayHint.split('-'))
if displayHintType == 'x':
return '0x%x' % value
elif displayHintType == 'd':
try:
return '%.*f' % (int(decimalPrecision), float(value) /
pow(10, int(decimalPrecision)))
except Exception:
raise SmiError('float evaluation error: %s' %
sys.exc_info()[1])
elif displayHintType == 'o':
return '0%o' % value
elif displayHintType == 'b':
runningValue = value
outputValue = ['B']
while runningValue:
outputValue.insert(0, '%d' % (runningValue & 0x01))
runningValue >>= 1
return ''.join(outputValue)
else:
raise SmiError('Unsupported numeric type spec "%s" at %s' %
(displayHintType, self.__class__.__name__))
elif self.displayHint and self.__octetString.isSuperTypeOf(
self, matchConstraints=False):
outputValue = ''
runningValue = OctetString(value).asOctets()
displayHint = self.displayHint
while runningValue and displayHint:
# 1
if displayHint[0] == '*':
repeatIndicator = repeatCount = octets.oct2int(
runningValue[0])
displayHint = displayHint[1:]
runningValue = runningValue[1:]
else:
repeatCount = 1
repeatIndicator = None
# 2
octetLength = ''
while displayHint and displayHint[0] in string.digits:
octetLength += displayHint[0]
displayHint = displayHint[1:]
# length is manatory, but people ignore that
if not octetLength:
octetLength = len(runningValue)
try:
octetLength = int(octetLength)
except Exception:
raise SmiError('Bad octet length: %s' % octetLength)
if not displayHint:
raise SmiError('Short octet length: %s' % self.displayHint)
# 3
displayFormat = displayHint[0]
displayHint = displayHint[1:]
# 4
if displayHint and displayHint[
0] not in string.digits and displayHint[0] != '*':
displaySep = displayHint[0]
displayHint = displayHint[1:]
else:
displaySep = ''
# 5
if displayHint and displaySep and repeatIndicator is not None:
repeatTerminator = displayHint[0]
displaySep = ''
displayHint = displayHint[1:]
else:
repeatTerminator = None
while repeatCount:
repeatCount -= 1
if displayFormat == 'a':
outputValue += runningValue[:octetLength].decode(
'ascii', 'ignore')
elif displayFormat == 't':
outputValue += runningValue[:octetLength].decode(
'utf-8', 'ignore')
elif displayFormat in ('x', 'd', 'o'):
number = 0
numberString = runningValue[:octetLength]
while numberString:
number <<= 8
try:
number |= octets.oct2int(numberString[0])
numberString = numberString[1:]
except Exception:
raise SmiError(
'Display format eval failure: %s: %s' %
(numberString, sys.exc_info()[1]))
if displayFormat == 'x':
outputValue += '%02x' % number
elif displayFormat == 'o':
outputValue += '%03o' % number
else:
outputValue += '%d' % number
else:
raise SmiError('Unsupported display format char: %s' %
displayFormat)
if runningValue and repeatTerminator:
outputValue += repeatTerminator
runningValue = runningValue[octetLength:]
if runningValue and displaySep:
outputValue += displaySep
if not displayHint:
displayHint = self.displayHint
return outputValue
for base in inspect.getmro(self.__class__):
if not issubclass(base, TextualConvention) and issubclass(
base, Asn1Item):
return base.prettyOut(self, value)
raise SmiError('TEXTUAL-CONVENTION has no underlying SNMP base type')
def __call__(self,
substrate,
asn1Spec=None,
tagSet=None,
length=None,
state=stDecodeTag,
recursiveFlag=1,
substrateFun=None,
allowEoo=False):
if debug.logger & debug.flagDecoder:
debug.logger(
'decoder called at scope %s with state %d, working with up to %d octets of substrate: %s'
%
(debug.scope, state, len(substrate), debug.hexdump(substrate)))
if asn1Spec is not None and not isinstance(
asn1Spec, (base.Asn1Item, tagmap.TagMap)):
raise error.PyAsn1Error(
'asn1Spec is not valid (should be an instance of an ASN.1 Item, not %s)'
% asn1Spec.__class__.__name__)
value = base.noValue
fullSubstrate = substrate
while state != stStop:
if state == stDecodeTag:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on tag decoding')
if not isOctetsType(substrate) and \
not isinstance(substrate, univ.OctetString):
raise error.PyAsn1Error('Bad octet stream type')
# Decode tag
firstOctet = substrate[0]
substrate = substrate[1:]
if firstOctet in self.__tagCache:
lastTag = self.__tagCache[firstOctet]
else:
t = oct2int(firstOctet)
# Look for end-of-octets sentinel
if t == 0:
if substrate and oct2int(substrate[0]) == 0:
if allowEoo and self.supportIndefLength:
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'end-of-octets sentinel found')
value, substrate = eoo.endOfOctets, substrate[
1:]
state = stStop
continue
else:
raise error.PyAsn1Error(
'Unexpected end-of-contents sentinel')
else:
raise error.PyAsn1Error('Zero tag encountered')
tagClass = t & 0xC0
tagFormat = t & 0x20
tagId = t & 0x1F
short = True
if tagId == 0x1F:
short = False
tagId = 0
while True:
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on long tag decoding')
t = oct2int(substrate[0])
tagId = tagId << 7 | (t & 0x7F)
substrate = substrate[1:]
if not t & 0x80:
break
lastTag = tag.Tag(tagClass=tagClass,
tagFormat=tagFormat,
tagId=tagId)
if short:
# cache short tags
self.__tagCache[firstOctet] = lastTag
if tagSet is None:
if firstOctet in self.__tagSetCache:
tagSet = self.__tagSetCache[firstOctet]
else:
# base tag not recovered
tagSet = tag.TagSet((), lastTag)
if firstOctet in self.__tagCache:
self.__tagSetCache[firstOctet] = tagSet
else:
tagSet = lastTag + tagSet
state = stDecodeLength
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'tag decoded into %s, decoding length' % tagSet)
if state == stDecodeLength:
# Decode length
if not substrate:
raise error.SubstrateUnderrunError(
'Short octet stream on length decoding')
firstOctet = oct2int(substrate[0])
if firstOctet == 128:
size = 1
length = -1
elif firstOctet < 128:
length, size = firstOctet, 1
else:
size = firstOctet & 0x7F
# encoded in size bytes
length = 0
lengthString = substrate[1:size + 1]
# missing check on maximum size, which shouldn't be a
# problem, we can handle more than is possible
if len(lengthString) != size:
raise error.SubstrateUnderrunError(
'%s<%s at %s' % (size, len(lengthString), tagSet))
for char in lengthString:
length = (length << 8) | oct2int(char)
size += 1
substrate = substrate[size:]
if length != -1 and len(substrate) < length:
raise error.SubstrateUnderrunError(
'%d-octet short' % (length - len(substrate)))
if length == -1 and not self.supportIndefLength:
error.PyAsn1Error(
'Indefinite length encoding not supported by this codec'
)
state = stGetValueDecoder
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'value length decoded into %d, payload substrate is: %s' %
(length,
debug.hexdump(length == -1 and substrate
or substrate[:length])))
if state == stGetValueDecoder:
if asn1Spec is None:
state = stGetValueDecoderByTag
else:
state = stGetValueDecoderByAsn1Spec
#
# There're two ways of creating subtypes in ASN.1 what influences
# decoder operation. These methods are:
# 1) Either base types used in or no IMPLICIT tagging has been
# applied on subtyping.
# 2) Subtype syntax drops base type information (by means of
# IMPLICIT tagging.
# The first case allows for complete tag recovery from substrate
# while the second one requires original ASN.1 type spec for
# decoding.
#
# In either case a set of tags (tagSet) is coming from substrate
# in an incremental, tag-by-tag fashion (this is the case of
# EXPLICIT tag which is most basic). Outermost tag comes first
# from the wire.
#
if state == stGetValueDecoderByTag:
if tagSet in self.__tagMap:
concreteDecoder = self.__tagMap[tagSet]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
_k = tagSet[:1]
if _k in self.__tagMap:
concreteDecoder = self.__tagMap[_k]
else:
concreteDecoder = None
if concreteDecoder:
state = stDecodeValue
else:
state = stTryAsExplicitTag
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger(
'codec %s chosen by a built-in type, decoding %s' %
(concreteDecoder and concreteDecoder.__class__.__name__
or "<none>", state == stDecodeValue and 'value'
or 'as explicit tag'))
debug.scope.push(
concreteDecoder is None and '?'
or concreteDecoder.protoComponent.__class__.__name__)
if state == stGetValueDecoderByAsn1Spec:
if isinstance(asn1Spec, (dict, tagmap.TagMap)):
if tagSet in asn1Spec:
__chosenSpec = asn1Spec[tagSet]
else:
__chosenSpec = None
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger('candidate ASN.1 spec is a map of:')
for t, v in asn1Spec.getPosMap().items():
debug.logger(' %s -> %s' %
(t, v.__class__.__name__))
if asn1Spec.getNegMap():
debug.logger('but neither of: ')
for t, v in asn1Spec.getNegMap().items():
debug.logger(' %s -> %s' %
(t, v.__class__.__name__))
debug.logger(
'new candidate ASN.1 spec is %s, chosen by %s' %
(__chosenSpec is None and '<none>'
or __chosenSpec.prettyPrintType(), tagSet))
else:
__chosenSpec = asn1Spec
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'candidate ASN.1 spec is %s' %
asn1Spec.__class__.__name__)
if __chosenSpec is not None and (
tagSet == __chosenSpec.getTagSet()
or tagSet in __chosenSpec.getTagMap()):
# use base type for codec lookup to recover untagged types
baseTagSet = __chosenSpec.baseTagSet
if __chosenSpec.typeId is not None and \
__chosenSpec.typeId in self.__typeMap:
# ambiguous type
concreteDecoder = self.__typeMap[__chosenSpec.typeId]
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'value decoder chosen for an ambiguous type by type ID %s'
% (__chosenSpec.typeId, ))
elif baseTagSet in self.__tagMap:
# base type or tagged subtype
concreteDecoder = self.__tagMap[baseTagSet]
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'value decoder chosen by base %s' % (baseTagSet, ))
else:
concreteDecoder = None
if concreteDecoder:
asn1Spec = __chosenSpec
state = stDecodeValue
else:
state = stTryAsExplicitTag
else:
concreteDecoder = None
state = stTryAsExplicitTag
if debug.logger and debug.logger & debug.flagDecoder:
debug.logger(
'codec %s chosen by ASN.1 spec, decoding %s' %
(state == stDecodeValue
and concreteDecoder.__class__.__name__
or "<none>", state == stDecodeValue and 'value'
or 'as explicit tag'))
debug.scope.push(__chosenSpec is None and '?'
or __chosenSpec.__class__.__name__)
if state == stTryAsExplicitTag:
if tagSet and tagSet[0][1] == tag.tagFormatConstructed and \
tagSet[0][0] != tag.tagClassUniversal:
# Assume explicit tagging
concreteDecoder = explicitTagDecoder
state = stDecodeValue
else:
concreteDecoder = None
state = self.defaultErrorState
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'codec %s chosen, decoding %s' %
(concreteDecoder and concreteDecoder.__class__.__name__
or "<none>", state == stDecodeValue and 'value'
or 'as failure'))
if state == stDumpRawValue:
concreteDecoder = self.defaultRawDecoder
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'codec %s chosen, decoding value' %
concreteDecoder.__class__.__name__)
state = stDecodeValue
if state == stDecodeValue:
if recursiveFlag == 0 and not substrateFun: # legacy
def substrateFun(a, b, c):
return a, b[:c]
if length == -1: # indef length
value, substrate = concreteDecoder.indefLenValueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun)
else:
value, substrate = concreteDecoder.valueDecoder(
fullSubstrate, substrate, asn1Spec, tagSet, length,
stGetValueDecoder, self, substrateFun)
state = stStop
debug.logger and debug.logger & debug.flagDecoder and debug.logger(
'codec %s yields type %s, value:\n%s\n...remaining substrate is: %s'
% (concreteDecoder.__class__.__name__,
value.__class__.__name__, value.prettyPrint(),
substrate and debug.hexdump(substrate) or '<none>'))
if state == stErrorCondition:
raise error.PyAsn1Error('%s not in asn1Spec: %s' %
(tagSet, asn1Spec))
if debug.logger and debug.logger & debug.flagDecoder:
debug.scope.pop()
debug.logger('decoder left scope %s, call completed' % debug.scope)
return value, substrate
def encodeValue(self, value, asn1Spec, encodeFun, **options):
if asn1Spec is not None:
value = asn1Spec.clone(value)
if value.isPlusInf:
return (0x40,), False, False
if value.isMinusInf:
return (0x41,), False, False
m, b, e = value
if not m:
return null, False, True
if b == 10:
if LOG:
LOG('encoding REAL into character form')
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), False, True
elif b == 2:
fo = 0x80 # binary encoding
ms, m, encbase, e = self._chooseEncBase(value)
if ms < 0: # mantissa sign
fo |= 0x40 # sign bit
# exponent & mantissa normalization
if encbase == 2:
while m & 0x1 == 0:
m >>= 1
e += 1
elif encbase == 8:
while m & 0x7 == 0:
m >>= 3
e += 1
fo |= 0x10
else: # encbase = 16
while m & 0xf == 0:
m >>= 4
e += 1
fo |= 0x20
sf = 0 # scale factor
while m & 0x1 == 0:
m >>= 1
sf += 1
if sf > 3:
raise error.PyAsn1Error('Scale factor overflow') # bug if raised
fo |= sf << 2
eo = null
if e == 0 or e == -1:
eo = int2oct(e & 0xff)
else:
while e not in (0, -1):
eo = int2oct(e & 0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
if e == -1 and eo and not (oct2int(eo[0]) & 0x80):
eo = int2oct(0xff) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n & 0xff) + eo
po = null
while m:
po = int2oct(m & 0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, False, True
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
def test_oct2int(self):
assert 12 == octets.oct2int(bytes([12]))[0]